calcium peroxide application. Method for producing calcium peroxide

The invention relates to the technology of calcium peroxide. In the method for producing calcium peroxide, calcium hydroxide is reacted with an aqueous solution of hydrogen peroxide at a molar ratio of H 2 O 2:Ca(OH) 2 equal to 1.2-7.0 to form calcium peroxide hydrate. Calcium hydroxide is introduced into the reaction in the form of an aqueous suspension of calcium oxide, a solution of hydrogen peroxide is introduced by controlled feeding at a rate of 0.006-0.060 mol H 2 O 2 per mol Ca(OH) 2 per minute. Before the thermal dehydration step, the calcium peroxide hydrate precipitate is separated from the solution by decantation. Thermal dehydration is carried out in a stream of heated air. The interaction of calcium hydroxide with an aqueous solution of hydrogen peroxide is carried out in the presence of a peroxide stabilizer with a concentration of 10 -3 -10 -5 mol/l, which is selected from the series: alkali metal phosphate, ethylenediaminetetraacetic acid, polyethylene glycol complex with phosphorus (V) oxide. The proposed method makes it possible to expand the raw material base of calcium peroxide technology, eliminate the energy-intensive stages of cooling the reaction mixture and filtering finely dispersed calcium peroxide hydrate, and simplify the process chain. 1 z.p. f-ly, 1 tab.

The invention relates to a technology for the production of calcium peroxide, the practical application of which is associated with the generation of oxygen for oxidation processes, which determines the possibility of its use as an oxygen source in the food, perfume industry, agriculture, medicine, household chemicals, etc.

The advantages of CaO 2 in comparison with other solid carriers of active oxygen are the ecological purity of the end products of its transformation or decomposition - Ca(OH) 2 , CaCO 2 , O 2 , H 2 O, as well as its increased stability under storage conditions.

A known method for producing calcium peroxide by reacting an aqueous solution of calcium chloride with ammonia 3.8-20% solution of hydrogen peroxide at 20-60°C, followed by dehydration of calcium peroxide hydrate at atmospheric pressure [and.with. USSR No. 1281507, 1987]. The disadvantage of this method is the complexity of the technology associated with the use of ammonia solution, which imposes severe restrictions on the safety of the production area.

A known method for producing calcium peroxide by reacting an aqueous solution of calcium chloride, 10% NaOH solution and 30% H 2 O 2 solution. The NaOH solution additionally contains 6.02-10 wt.% NaCl. The reaction mixture has a pH of 10-12. The resulting precipitate is filtered off, washed with water and dried at 125°C. The disadvantage of this method is the complexity of the technology associated with the need to control the content of NaCl in the solution, and increased energy consumption for its implementation.

A method is known for producing calcium peroxide by dehydration of calcium peroxide diperoxosolvate. According to one variant of this method, dehydration is carried out at a residual pressure P=10-10 -2 mm Hg. and an initial temperature of 0-10°C with an increase in temperature in the process of dehydration up to 140-160°C. According to another variant, dehydration is carried out at atmospheric pressure and at a temperature of 0-250°C in a stream of dried, carbon dioxide-free air. The diperoxo solvate of calcium peroxide is treated with a chilled anhydrous inert liquid before dehydration. Dehydration is carried out in the presence of a water vapor absorber. The disadvantage of this method is the complexity of the technology and increased energy consumption.

A known method for producing calcium peroxide by reacting dry calcium hydroxide or its 50% aqueous suspension with a 16-35% aqueous solution of hydrogen peroxide at a ratio of hydrogen peroxide to calcium hydroxide equal to 1.2-2.0. The interaction product is subjected to dehydration at 40-170°C with preliminary filtration at a residual pressure of 0.1-10.0 mm Hg. or by sublimation at a residual pressure of 10 -2 -10 -3 mm Hg. . The disadvantage of this method is the complexity of the technology at the stage of product isolation, which leads to increased energy consumption.

A known method for producing calcium peroxide by dehydration of calcium peroxide diperoxohydrate at atmospheric pressure in the presence of a water vapor absorber. Dehydration is carried out at negative temperatures down to -15°C. The disadvantage of this method is the complexity of the technology associated with the presence of an additional stage for obtaining diperoxohydrate, as well as the need for its decomposition at low temperatures.

A known method for producing calcium peroxide by reacting calcium hydroxide or salts in an alkaline environment with hydrogen peroxide. Oxygen-containing organic substances with a boiling point of not more than 300 ° C are introduced into hydrogen peroxide, for example, ethyl alcohol, acetone, dioxane [a.s. USSR No. 421621, 1974]. The disadvantage of this method is the use of organic substances that contaminate the target product and thereby limit its use or require additional purification of the product.

Closest to the claimed method is a method for producing calcium peroxide, including the interaction of dry calcium hydroxide with an aqueous solution of hydrogen peroxide with the formation of calcium peroxide hydrate and its subsequent thermal dehydration [and.with. USSR No. 1532547, SW 15/043, 1982] (prototype). A 3-35% aqueous solution of hydrogen peroxide is used at a molar ratio of H 2 O 2:Ca(OH) 2 equal to 1.2-7.0. As follows from the examples, the solution is cooled, filtered and dehydrated under vacuum. The dehydration temperature is 20-140°C.

The main disadvantage of this method is the use of dry calcium hydroxide as a raw material, an expensive product, which is subject to stringent technological safety requirements, such as protection from moisture and carbon dioxide. The use of vacuum at the stage of thermal dehydration also complicates and increases the cost of the technology. The disadvantages of the method include the presence of the stage of forced cooling of the reaction mixture and the laborious stage of filtering the fine precipitate of calcium peroxide hydrate.

The technical task is to expand the raw material base in the technology of calcium peroxide.

The invention is aimed at finding a method for producing calcium peroxide from quicklime, excluding the energy-intensive step of cooling the intermediate product while simplifying the entire technological chain.

The technical result is achieved by the fact that a method for producing calcium peroxide is proposed, including the interaction of calcium hydroxide with an aqueous solution of hydrogen peroxide at a molar ratio of H 2 O 2:Ca(OH) 2 equal to 1.2-7.0, with the formation of calcium peroxide hydrate, its thermal dehydration, while according to the invention, calcium hydroxide is introduced into the reaction in the form of an aqueous suspension of calcium oxide, a solution of hydrogen peroxide is introduced by controlled supply at a rate of 0.006-0.060 mol H 2 O 2 per mol Ca(OH) 2 per minute, before the stage of thermal dehydration, the precipitate of calcium peroxide hydrate is separated from the solution by decantation, and thermal dehydration is carried out in a stream of heated air.

Preferably, the interaction of calcium hydroxide with an aqueous solution of hydrogen peroxide is carried out in the presence of a peroxide stabilizer with a concentration of 10 -3 -10 -5 mol/l, which is selected from the series: alkali metal phosphate; ethylenediaminetetraacetic acid; complex of polyethylene glycol with phosphorus (V) oxide.

Reducing energy consumption in the claimed method is achieved by controlled supply of an aqueous solution of hydrogen peroxide to an aqueous suspension of calcium oxide. The feed rate of 0.006-0.060 mol H 2 O 2 per mol Ca(OH) 2 per minute is chosen from the condition that for all declared molar ratios of H 2 O 2 to Ca(OH) 2, the temperature in the zone of the exothermic reaction of the formation of calcium peroxide hydrate is not will exceed 40°C. Controlled supply of H 2 O 2 solution eliminates the stage of forced cooling of the reaction mixture.

The use of affordable and cheap quicklime - calcium oxide - as an initial reagent significantly expands the raw material base of calcium peroxide technology.

The simplification of the technology is achieved by eliminating the forced cooling of the reaction mixture due to the controlled supply of a hydrogen peroxide solution, as well as by replacing the filtration process with decantation at the stage of separating the fine precipitate of calcium peroxide hydrate from the mother liquor.

The presence of a hydrogen peroxide stabilizer provides a more complete yield of the intermediate product and, consequently, of calcium peroxide.

Calcium peroxide is obtained as follows.

A 3.0-37% aqueous solution of hydrogen peroxide is added to a 20-30% aqueous suspension of calcium oxide in an amount that provides a molar ratio of H 2 O 2: Ca (OH) 2 equal to 1.2-7.0, at a rate of 0.006- 0.060 mol H 2 O 2 per mol Ca(OH) 2 per minute. Precipitation of fine calcium peroxide hydrate is carried out for 2 hours, after which the precipitate is separated from the mother liquor by decantation. The precipitate is dried in a stream of heated air for 2 hours. The resulting product is analyzed for the content of active oxygen, after which its yield is determined.

Below are examples of the implementation of the claimed method.

100 ml of H 2 O are added to 30 g of CaO over 30 minutes. 42 ml of 35% H 2 O 2 are poured into the resulting suspension at a feed rate of 0.006 mol H 2 O 2 per mol Ca(OH) 2 per minute. Within ˜30 minutes, a molar ratio of H 2 O 2:Ca(OH) 2 equal to 1.2 is reached. The temperature in the reaction zone is maintained within 30-40°C. The precipitation of Ca(OH) 2 with the mother liquor is left to settle in the reaction vessel for 2 hours. The compacted precipitate is separated from the mother liquor by decantation and dehydrated in a stream of heated air for 2 hours. 26.4 g of CaO 2 are obtained with a yield of 49.8 wt.%. Analysis: found O act. - 11.1 wt.%

Examples 2-12 are implemented similarly to Example 1 and are summarized in the Table.

Table Examples of the implementation of the method for producing calcium peroxide
N	molar ratio of H 2 O 2: Ca (OH) 2	Feed rate mol H 2 O 2 per mol Ca (OH) 2 per minute	O act. , wt %	Yield of CaO 2 , wt.%	Stabilizer, mol/l
1	1,2	0,006	11,1	49,8
2	4,0	0,006	12,1	54,6
3	7,0	0,006	13,5	60,9
4	1,2	0,010	10,5	47,2
5	4,0	0,010	11,4	51,3
6	7,0	0,010	13,1	59,0
7	1,2	0,060	10,8	48,6
8	4,0	0,060	11,9	53,6
9	7,0	0,060	13,0	58,7
10	4,0	0,020	14,8	66,6	1 10 -3
11	4,0	0,020	14,6	65,8	1 10 -4
12	4,0	0,020	14,7	66,3	1 10 -5

As follows from the data obtained, calcium peroxide with a purity of up to 50 wt.% can be obtained using a hydrogen peroxide solution of 3-35% concentration and a molar ratio of H 2 O 2:Ca(OH) 2 =1.2. Increasing the molar ratio to 4-7 makes it possible to obtain high percentage calcium peroxide (60 wt.% CaO 2) even when using dilute solutions of H 2 O 2 (<8%).

In the presence of a peroxide stabilizer, the yield of calcium peroxide increases, as can be seen from Examples 10-12 of the Table.

The proposed method allows expanding the raw material base of calcium peroxide technology through the use of quicklime, eliminating the energy-intensive stages of cooling the reaction mixture and filtering finely dispersed calcium peroxide hydrate, and simplifying the process chain. Calcium peroxide is obtained with a purity of 50-65 wt.%.

CLAIM

1. A method for producing calcium peroxide, including the interaction of calcium hydroxide with an aqueous solution of hydrogen peroxide at a molar ratio of H 2 O 2: Ca (OH) 2 equal to 1.2-7.0 with the formation of calcium peroxide hydrate, its thermal dehydration, characterized in that that calcium hydroxide is introduced into the reaction in the form of an aqueous suspension of calcium oxide, a solution of hydrogen peroxide is introduced by controlled supply at a rate of 0.006-0.060 mol H 2 O 2 per mol Ca(OH) 2 per minute, before the stage of thermal dehydration, the precipitate of calcium peroxide hydrate is separated from the solution by decantation, and thermal dehydration is carried out in a stream of heated air.

2. The method according to claim 1, characterized in that the interaction of calcium hydroxide with an aqueous solution of hydrogen peroxide is carried out in the presence of a peroxide stabilizer with a concentration of 10 -3 -10 -5 mol / l, which is selected from the series: alkali metal phosphate, ethylenediaminetetraacetic acid, complex of polyethylene glycol with phosphorus (V) oxide.

From Wikipedia, the free encyclopedia

General
calcium peroxide
Systematic Name	calcium peroxide
Traditional names	calcium peroxide
Chem. formula	CaO2
Physical Properties
State	White powder
Molar mass	72.08 g/mol
Density	2.92 g/cm³
Thermal properties
T. melt.	dec. 275°C
Classification
Reg. CAS number	1305-79-9
PubChem	14779
SMILES
RTECS	EW3865000
Data is based on standard conditions (25 °C, 100 kPa) unless otherwise noted.

calcium peroxide- binary inorganic compound of calcium and oxygen with the formula CaO 2 . White powder.

Receipt

\mathsf(Ca(OH)_2 + H_2O_2 \ \xrightarrow(50^oC)\ CaO_2\downarrow + 2\ H_2O )

when carrying out the reaction in cooled aqueous solutions, a crystalline CaO 2 8H 2 O is obtained.

Physical Properties

Calcium peroxide forms white small tetragonal crystals, space group I 4/mmm, cell parameters a= 0.501 nm, c= 0.592 nm, Z = 2.

Calcium peroxide hydrate CaO 2 8H 2 O is a brilliant white powder with a density of 1.672 g / cm³ of the tetragonal system, space group P4/mcc, cell parameters a= 0.621 nm, c= 1.100 nm, Z = 2.

Chemical properties

When heated, it decomposes:

\mathsf(2\ CaO_2 \ \xrightarrow(250^oC)\ 2\ CaO + O_2 )

Decomposes slowly with hot water

\mathsf(CaO_2 + 2\ H_2O \ \xrightarrow(50^oC)\ Ca(OH)_2 + H_2O_2 )

Reacts with acids

\mathsf(CaO_2 + 2\ HCl \ \xrightarrow(\ )\ CaCl_2 + H_2O_2 )

Application

Calcium peroxide in the form of food additive E-930 is mainly used as a flour and bread improver and is included in the list of flour processing agents. Price ≈500$/t.

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Literature

Ripan R., Chetyanu I. Inorganic chemistry. Chemistry of metals. - M .: Mir, 1971. - T. 1. - 561 p.
Chemical Encyclopedia / Ed.: Knunyants I.L. and others. - M .: Soviet Encyclopedia, 1990. - T. 2. - 671 p. - ISBN 5-82270-035-5.
Handbook of a chemist / Editorial board: Nikolsky B.P. and others. - 2nd ed., corrected. - M.-L.: Chemistry, 1966. - T. 1. - 1072 p.
Handbook of a chemist / Editorial board: Nikolsky B.P. and others. - 3rd ed., corrected. - L.: Chemistry, 1971. - T. 2. - 1168 p.

This article about inorganic matter is a stub. You can help the project by adding to it.

An excerpt characterizing calcium peroxide

Three days later, the little princess was buried, and, saying goodbye to her, Prince Andrei ascended the steps of the coffin. And in the coffin was the same face, although with closed eyes. "Oh, what have you done to me?" everything said it, and Prince Andrei felt that something had come off in his soul, that he was guilty of guilt, which he could not correct and not forget. He couldn't cry. The old man also entered and kissed her wax pen, which lay high and calm on the other, and her face said to him: “Ah, what and why did you do this to me?” And the old man turned away angrily when he saw that face.

Five days later, the young Prince Nikolai Andreevich was baptized. Mammy held the diapers with her chin, while the priest smeared the boy's wrinkled red palms and steps with a goose feather.
The godfather, the grandfather, fearing to drop, shuddering, carried the baby around a crumpled tin font and handed it over to the godmother, Princess Marya. Prince Andrei, trembling with fear lest the child be drowned, sat in another room, waiting for the end of the sacrament. He joyfully looked at the child when his nanny carried him out, and nodded his head approvingly when the nanny informed him that the wax with hairs thrown into the font did not sink, but floated along the font.

Rostov's participation in the duel between Dolokhov and Bezukhov was hushed up through the efforts of the old count, and Rostov, instead of being demoted, as he expected, was appointed adjutant to the Moscow governor general. As a result, he could not go to the village with the whole family, but remained at his new position all summer in Moscow. Dolokhov recovered, and Rostov became especially friendly with him at this time of his recovery. Dolokhov lay ill with his mother, who passionately and tenderly loved him. Old Marya Ivanovna, who fell in love with Rostov for his friendship with Fedya, often spoke to him about her son.
“Yes, count, he is too noble and pure in soul,” she used to say, “for our present, corrupted world. No one likes virtue, it pricks everyone's eyes. Well, tell me, Count, is this fair, is it honestly from Bezukhov's side? And Fedya, in his nobility, loved him, and now he never says anything bad about him. In St. Petersburg, these pranks with the quarterly were joking there, because they did it together? Well, nothing to Bezukhov, but Fedya endured everything on his shoulders! After all, what did he endure! Let's say they returned it, but why not return it? I think there were not many brave men and sons of the fatherland like him. Well now - this duel! Do these people have a sense of honor! Knowing that he is the only son, challenge him to a duel and shoot so straight! It's good that God has mercy on us. And for what? Well, who in our time does not have intrigue? Well, if he is so jealous? I understand, because before he could make you feel, otherwise the year went on. And well, he challenged him to a duel, believing that Fedya would not fight, because he owed him. What meanness! That's disgusting! I know you understand Fedya, my dear Count, that's why I love you with my soul, believe me. Few people understand him. This is such a high, heavenly soul!
Dolokhov himself often, during his recovery, spoke to Rostov such words that could not be expected from him. - They consider me an evil person, I know, - he used to say, - and let them. I don't want to know anyone except those whom I love; but whom I love, I love him so that I will give my life, and I will hand over the rest to everyone if they stand on the road. I have an adored, invaluable mother, two or three friends, including you, and I pay attention to the rest only as much as they are useful or harmful. And almost all are harmful, especially women. Yes, my soul, - he continued, - I met men who were loving, noble, exalted; but women, except for corrupt creatures - countesses or cooks, all the same - I have not yet met. I have not yet met that heavenly purity, devotion, which I am looking for in a woman. If I found such a woman, I would give my life for her. And these!…” He made a contemptuous gesture. – And do you believe me, if I still value life, I value it only because I still hope to meet such a heavenly being who would revive, purify and elevate me. But you don't understand it.
“No, I understand very well,” answered Rostov, who was under the influence of his new friend.

In autumn the Rostov family returned to Moscow. At the beginning of winter, Denisov also returned and stopped at the Rostovs. This first time of the winter of 1806, spent by Nikolai Rostov in Moscow, was one of the happiest and most cheerful for him and for his entire family. Nikolai attracted many young people to his parents' house. Vera was twenty years old, a beautiful girl; Sonya is a sixteen-year-old girl in all the beauty of a freshly blossomed flower; Natasha is half young lady, half girl, sometimes childishly funny, sometimes girlishly charming.

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MINISTRY OF EDUCATION AND SCIENCE OF RUSSIA

Federal State Budgetary Educational Institution

higher professional education

“Chuvash State University named after I.N. Ulyanov"

Faculty of Chemistry and Pharmacy

Department of Chemical Technology and Environmental Protection

on educational (familiarization) practice

on the topic: Technology for the production of calcium peroxide

Completed by a student of the group: Х-31-12 signature:________26. 07. 14 Ivleva I.V.

Checked by: A.N.

Cheboksary 2014

Characteristics of the feedstock, materials and manufactured products (quantity, composition, regulatory requirements, etc.)

Conclusion

List of used literature

General information about the enterprise, organization, structural unit

JSC "Khimprom" is one of the key enterprises of the domestic chemical industry, whose activities are focused on large-tonnage chemistry. It produces more than 150 items and brands of products that are in demand in the domestic and international markets. The company's development strategy is focused on the production of products with high added value, the construction of new and modernization of existing production facilities at existing sites, the creation of new promising products.

JSC "Khimprom" is actively engaged in research work in the field of chemistry, energy efficiency and ecology. The main production complexes are inorganic, organic, organochlorine, organophosphorus, organosilicon, rubber chemicals, surfactants, as well as reagents for heat power engineering, oil production and oil refining industry.

The plant is developing the largest hydrogen peroxide production in Russia, which meets international standards and meets the needs of the textile and pulp and paper industries in environmentally friendly bleaches.

JSC "Khimprom" focuses on a high level of business culture - modern standards of corporate governance, quality control of production and finished products, service for its customers. Therefore, the company and our products have a good reputation in Russia and abroad: 20% of deliveries are exported to 28 countries of the world. The company's quality management system has been verified and found to comply with the requirements of ISO 9001:2008.

Characteristics of raw materials, materials and manufactured products

Production name - calcium peroxide (percalcite).

Percalcite production is located in building 602a. Year of commissioning - 1994. Designed production capacity - 1000 tons. Achieved production capacity - 453 tons. Production method - batch. Production is single-fired.

Percalcite is obtained by reacting calcium hydroxide with hydrogen peroxide and subsequent drying of the reaction mass. The designer of the construction part is PKO ChPO "Khimprom". The designer of the technological part is PKO ChPO "Khimprom". The technological process of percalcite was developed by the Research and Development Center of the ChPO "Khimprom"

Characteristics of manufactured products

Calcium peroxide is an environmentally friendly, non-toxic, oxygen-rich substance. It is a white to light yellow powder. Calcium peroxide has an antimicrobial effect, when added to feed, it disinfects them, increases the growth rate, safety and productivity of animals and birds.

Percalcite consists of: calcium peroxide - 60%, calcium hydroxide - 25%, calcium carbonate - 10.5%, magnesium oxide - 1%, oxides of aluminum, iron, silicon - 0.6%, water - 2.8%, t i.e. contains 95.6% calcium compounds, which in terms of CaCO3 is 50% more effective than the best grades of lime.

When interacting with soil moisture, it slowly (within 60-75 days) hydrolyzes with the formation of hydroxide, calcium salts and atomic oxygen. The drug adjusts the pH, reduces the acidity and salinity of the soil.

Percalcite is used as a plant growth regulator in pesticide-free rice cultivation. Increases yield up to 20%. It has nematicidal properties. When disinfecting closed ground from gall nematodes, it is equivalent to vidat. Provides localization and elimination of foci of infection with root-knot nematodes without steaming or soil treatment with methyl bromide, the cost of treatment with the drug is 2-4 times less than when using steaming or methyl bromide.

Structural formula

The empirical formula of CaO 2

Molecular weight - 72.08

Basic physico-chemical properties

The crystalline powder is slightly soluble in cold water, slowly hydrolyzed by it to calcium hydroxide, in hot water faster, soluble in aqueous solutions of ammonium chloride, acids.

Application

Characteristics of raw materials, materials and semi-finished products

Name of raw materials, materials and semi-finished products	GOST, OST, TU, regulations or methodology for training	Indicators to check	Regulated indicators with tolerances

Building lime (hydrated)		Active CaO + MgO, not less than CO2, not more than
Hydrogen peroxide H - O - O - H H2O	301-02 -205-99 Grade A or Grade B	1.Appearance 2. Mass fraction of hydrogen peroxide, %	Colorless transparent liquid 35-40
Percalcite	TU 6-00-04691277-110-94 with amendments. №1,2	1.Appearance 2. Mass fraction of calcium peroxide, %, not less than	White to off-white crystalline powder Grade A Grade B 57.0 50.0

Raw materials are allowed into production based on the results of incoming control, carried out in accordance with the requirements of the JSC Khimprom enterprise standard STP - 35 - 98 "Incoming control of raw materials".

General production flow diagram and brief description technological process

Ca hydroxide

hydrogen peroxide

washing loss

hot air

packing losses

finished product

Stages and chemistry of the technological process.

1. Obtaining steam condensate.

2. Preparation of calcium hydroxide suspension.

3. Synthesis of calcium peroxide Ca(OH) 2 + H 2 O 2 CaO 2 + 2H 2 O(1)

4. Drying of the calcium peroxide suspension.

5. Preparation of the final form of percalcite.

Adverse reactions.

1. H 2 O 2 H 2 O + 1\2 O 2

2. Ca 2 * 8H 2 O + 2H 2 O 2 CaO 2 * 2H 2 O 2 + 8H 2 O

3. CaO 2 * 2H 2 O 2 CaO 2 + 2H 2 O + O 2

4. CaO 2 + H 2 O Ca (OH) 2 + 1\2 O 2

Detailed description of the scheme and the technological process of one of the stages

Description of the technological process

1. Receiving condensate

Steam from the main pipeline is fed into a shell-and-tube heat exchanger cooled by recycled water. Steam condensate from the heat exchanger enters the storage tank. Apparatus made of steel, enameled, with a capacity of 3200 dm 3 , equipped with an anchor stirrer with a rotation speed of 48 rpm, a jacket for heating with steam and cooling with circulating water, and a lower descent.

2. Preparation of calcium hydroxide suspension

A suspension of calcium hydroxide is prepared in a stainless steel apparatus with a capacity of 10,000 dm3, equipped with a crusher, an impeller mixer with a rotation speed of 105 rpm, and a jacket for cooling with cold brine. Water condensate with a volume of 2559.4 dm 3 is loaded into the apparatus from the apparatus (the level in dm is controlled by a certified meter), the stirrer is turned on and calcium hydroxide weighing 1700.9 kg is loaded through the hatch of the apparatus (in terms of 100% product). To capture calcium hydroxide, air containing calcium hydroxide dust is passed through a scrubber filled with water. By supplying brine into the jacket of the apparatus, the reaction mass is cooled to a temperature of 25-30 0 C and stirred at this temperature for an hour. Yield 99.76% based on loaded calcium hydroxide.

3. Synthesis of calcium peroxide

Reaction equation 1

A solution of hydrogen peroxide weighing 779.65 kg (in terms of 100% product) is loaded from the apparatus for a suspension of calcium hydroxide into the apparatus at a temperature of 25-30 0 C within 1-3 hours. Upon completion of loading hydrogen peroxide, the percalcite suspension is cooled to a temperature of at least 15 0 C and transferred with compressed air at a pressure of not more than 0.3 MPa at the drying stage to a pressure vessel.

The volume of percalcite suspension is 5641.6 dm 3 . The output at the stage is 68%, counting on calcium hydroxide.

4. Drying the calcium peroxide slurry

Drying of percalcite is carried out in a spray dryer. Before the start of drying, water is poured into the reducing device of the scrubber and the fan is turned on.

Check the operation of the dryer on water until the air temperature at the inlet and outlet of the dryer is automatically maintained within the specified limits.

After stabilization of the temperature, the dryer is transferred to the drying mode of the suspension of percalcite.

The temperature of the gas-air mixture at the exit to the dryer is 180:210 0 С. The temperature of the flue gases at the exit of the dryer is 105:120 0 С.

The suspension of percalcite from the pressure tank is fed into the spray turbine by a monopump and sprayed in the dryer chamber in a stream of hot air.

Dried percalcite settles on the walls of the conical bottom, from which it is shaken off with the help of electromagnetic hammers on the bottom of the dryer. Through a sector feeder, percalcite enters a receiving hopper mounted on weight scales or into mobile conveyors.

Percalcite is analyzed and, according to the analysis, sent to the mixer.

Air and water vapor containing percalcite are sucked by the chute fan with a vibrator into the bunker, the other part of the percalcite with air from the cyclone enters the wet scrubber, where the air is cleaned from the recirculating device and released into the atmosphere.

During the drying process, the water from the scrubbers, as it is saturated with calcium peroxide (the mass concentration of calcium peroxide is more than 20 g / dm 3 from the recirculating device, is periodically drained into the scrubber liquid collector, and from there, as it accumulates, it is pumped by a vortex pump into a pressure tank and then for drying. Percalcite output 63.16% based on loaded calcium hydroxide.

5. Preparation of the final form of percalcite

The preparation of the final form of percalcite is carried out in a batch mixer of a tape type designed for mixing bulk materials with liquid components, averaging heterogeneous over appearance, the content of the main substance, substances with a capacity of 10,000 dm 3 with a rotational speed of the ripper rotor of 0.33 rpm, equipped with mechanized loading and unloading, a filling factor of 0.4-0.7.

Dried percalcite for averaging the quality of the product is loaded into the mixer from the receiving hopper or container with the mixer drive turned off and stirred for an hour. The weight of the loaded product should not exceed 5 tons. At the end of mixing, the mixer drive is turned off and 2-3 samples are taken from different points of the mixer with a screw feeder and unloaded into a container marked in accordance with GOST 6732-4 with the application of manipulation signs "temperature limit" and "Protect from moisture" according to GOST 14192, classified code 5113 and danger sign according to GOST 19433 and additional inscription "Protect from impact". Net weight 25-30 kg.

The place of packaging is equipped with technological platform scales, model RP - 150 - 13Ts, GOST. The product is analyzed for all indicators. Finished products are assembled into a batch.

If the result of the analysis is negative, the quality of percalcite is adjusted, additionally stirred for two hours and re-analyzed.

The yield of percalcite is 62.83% based on the loaded calcium hydroxide.

6. Material balance per 1 ton of calcium peroxide

Conversion factor from one operation per 1 ton of commercial calcium peroxide:

The yield from theoretical, counting on calcium hydroxide is: 62.68%

name of raw materials	Molar mass, kg\mol	Mass fraction,%	Quantity in-va, mole	Density	Volume, dm 3


Preparation of calcium hydroxide suspension
LOADED: 1. Calcium hydroxide, incl. 2.water condensate RECEIVED: a) calcium hydroxide b) magnesium hydroxide c) calcium carbonate d) insoluble impurities e) water 2.Losses when loading calcium hydroxide from bags
Synthesis of calcium peroxide
LOADED: 1.Suspension of calcium hydroxide, incl. a) calcium hydroxide b) magnesium hydroxide c) calcium carbonate d) insoluble impurities e) water 2. Hydrogen peroxide, incl. a) hydrogen peroxide b) acetic acid c) non-volatile residue d) water RECEIVED: 1. Reaction mass from the synthesis stage, incl. a) calcium peroxide b) calcium hydroxide c) calcium carbonate d) magnesium hydroxide e) insoluble residue f) calcium acetate g) non-volatile residue h) water 2. Abgases, incl. a) oxygen

Technological regime standards, production control

Technological regime norms

Name of operation and reagents	Name of technological indicators
	Duration, h. min	Temperature, 0 С	Pressure, vacuum, MPa	Downloadable Components	Other indicators
				Mass (volume) fraction,%	Weight (kg) volume (dm 3)

Preparation of calcium hydroxide suspension.
1. Inspection of the apparatus (according to sch. 7-3) 2. Loading condensate 3. Loading calcium hydroxide 4. Cooling 5. Stirring						Pickle through shirt
Synthesis of calcium peroxide
1. Receiving hydrogen peroxide solution into the apparatus (according to sch.7-2) 2. Analysis 3. Loading hydrogen peroxide into the apparatus (according to sch. 7-3) 4. Cooling 5. Transfer of calcium peroxide suspension to the apparatus (according to sch. 0-77a, b)		At least 15		Not less than 35%		compressed air Samote-com Pickle through shirt compressed air
Drying the calcium peroxide slurry
1. Inspection of the dryer, preparation of the ventilation system for drying and its start-up 2. Drying of the calcium peroxide suspension 3. Sampling from the receiving hopper and analysis
Preparation of the final form and unloading of calcium peroxide
1.Inspection of equipment, mixer 2.Preparation and start-up of the air purification system 3.Loading of calcium peroxide 4.Stirring 5.Analysis 6.Unloading of calcium peroxide

The duration of the main cycle of calcium peroxide production is 69.10-71.10 hours.

Production control and process control

Name of process steps, measurement or sampling locations	Controlled parameter	Frequency and method of control	Norms and technical indicators	List of MVI and APCS standards	Position of instrumentation and automation system according to the scheme	Who controls

1. Preparation of calcium hydroxide suspension, apparatus 2. Synthesis of calcium peroxide Drying of calcium peroxide suspension. Dryer Air duct at the dryer inlet Air duct at the outlet of the dryer. Preparation of the final form and unloading of calcium peroxide.	1.Temperature tour 2.Temperature tour 3.Temperature tour 4. Pressure 5. Automatic temperature control 8. Appearance 9. Mass fraction of calcium peroxide in the dried powder 10. Appearance 11. Mass fraction of calcium peroxide in the product	After cooling While loading In the process of loading hydrogen peroxide After cooling In the process of squeezing the suspension, calcium peroxide Continuously in the drying process Constantly in the drying process After drying After mixing When unloading	Not more than 0.3 MPa No more than 125 Crystalline powder from white to cream color White to off-white crystalline powder	TU 6-00-04691277-110-94 with amendments. 1.2	Pos.7 platform scales Pos7. RP-150-13Ts	Apparatus-chik Apparatus-chik Apparatus-chik Apparatus-chik Apparatus-chik Apparatus-chik Apparatus-chik Apparatus-chik laboratory assistant laboratory assistant Laborant Apparatchik

Consumption rates for raw materials, materials, energy resources. Waste production

Annual consumption rates of the main types of raw materials, materials and energy resources

Name of raw materials, materials and energy resources. Naim. physical quantity and its unit of measurement	Considered mass fraction, %	Consumption rates
		By project	Scientific justification.	Planned by years

1. Hydrogen peroxide 2. Building lime 3.Bags-liners 4. Drums Energy resources: gas, steam here g/cal E/energy МВТ-4 River water t.m 3 Recycled water thousand m 3 Brine gcal.(-10)

Waste generation rates (per 1 ton of products) of production

Name of waste, compositions, apparatus or stage of surveys, name, physical, quantity and its unit of measurement	Direction, use, cleaning or disposal method	Waste generation standards
		By project	scientifically sound

solid waste
Container from under calcium hydroxide, kg	Sent to landfill
liquid waste
1. Calcium hydroxide solution, scrubber, including: a) hydroxide b) water
Gaseous waste
1. Emissions from the calcium peroxide synthesis stage: 1. Oxygen 2. Emissions from the stage of drying the calcium peroxide slurry in the dryer after the scrubber Abgazy. Including: 1. Removed water 2. calcium peroxide 3. calcium hydroxide 4. calcium carbonate. 5. Magnesium hydroxide 6. Calcium acetate 7. Insoluble and non-volatile residue 8. Oxygen	It is thrown out in atm.

Labor protection and industrial safety

Main production hazards

In the production of calcium peroxide, the main hazards are: 1. Thermal burns by steam due to non-density of flange joints of fittings when steam condensate is produced.

2. Electric shock.

3. Mechanical injuries when opening and closing hatches and cranes.

4. The possibility of chemical burns of the skin with building lime, hydrogen peroxide, the reaction mass when crushing, sampling, measuring the level in the apparatus, loading raw materials into an open hatch.

5. The possibility of a fire due to poor tightness of process and power equipment, communications, fittings and violation of mandatory instructions.

6. The possibility of poisoning by natural gas at high concentrations in the air, carbon monoxide - a product of incomplete combustion of natural gas.

7. The possibility of an explosion due to the formation of explosive mixtures of natural gas with air.

8. Violation of safety rules by employees.

Safety requirements for a planned shutdown of production, certain types of equipment and critical communications

Shutdown of equipment and communications are carried out on the basis of a written order of the head of the shop in accordance with the schedule.

During a planned shutdown of production, the equipment must be cleaned of dirt and sludge, neutralized, washed. After that, an analysis for the content of harmful substances and explosiveness must be performed.

If the result of the analysis is positive, the equipment is stunned from all communications with standard plugs and de-energized.

Equipment for repair is prepared by operating personnel under the guidance of a shift foreman.

The date, time, place of installation of each plug, the time of removal, as well as the names of the workers who installed and removed it, the name of the person at whose direction the plug was removed or installed, are recorded in a special journal "Journal of installation and removal of plugs".

Opening the apparatus or disconnecting the pipeline must be carried out only in the presence of a representative of the workshop administration. The person responsible for taking the equipment out for repair is obliged to provide ventilation in the workshop to exclude the possibility of flammable and toxic gases appearing at the repair workplaces.

When the equipment is taken out of reserve into operation, it must be pressurized, purged with compressed air, and equipped with instrumentation.

Gas hazardous work is carried out in accordance with the "Instruction for the organization of safe gas hazardous work at JSC Khimprom" (TB - 16). When repairing equipment, the safety rules set forth in the labor protection instructions TB - 1 - 9, in the work instructions for the mechanic - repairman of workshop No. 09 (RT - 40 - 9) must be observed.

Basic rules for emergency shutdown of production, its individual stages and apparatuses and responsible communications

A specific task to stop production is given by the shift foreman. An emergency shutdown of production and its individual stages is carried out in the event of emergency situations: severe gas contamination of the premises and territory, in case of fire, according to civil defense signals. In case of fire, call 01 or call the fire detector, start extinguishing the fire using primary fire extinguishing equipment.

In case of gas pollution, open windows, doors, inform the AGSS by phone 0 - 4; 54 - 24.

Stop conducting the technological process, inform the shift foreman and follow all his instructions in the future.

Phones: ambulance 0 - 3;

dispatcher 63 - 65; 53 - 39

In the event of an explosion of a gasified facility, turn off the gas supply, stop the process, inform the shift foreman, do not turn on or turn off electrical appliances, call the emergency service, by phone 54 - 24 and AGSS by phone 0 - 4.

Basic rules for putting equipment into operation after it has been stopped for repairs

Before starting, it is necessary to carefully check all devices, open their hatches, make sure that there are no foreign objects and liquids in them, close the hatch covers hermetically;

All process equipment and communications after repair must be tested for strength in accordance with the requirements of the MO instruction - 24: “On the procedure for conducting pneumatic tests for tightness of pressure vessels”;

Make sure that the shut-off and control valves are in good condition;

Check the correct rotation of agitators, pumps;

Check the correct operation of the instrumentation;

Make sure that there is circulating water, steam, instrumentation air, brine;

Make sure that general exchange ventilation and local exhausts work;

Acceptance of equipment for repair and its delivery from repair is reflected in the journal of preparation and delivery of equipment for repair.

Safety measures in the conduct of the technological process, the performance of routine production operations

Production safety measures, excluding the possibility of fires, poisoning, injuries, burns:

a) prevent overfilling of the apparatus and the ingress of products into the production room;

b) ensure reliable tightness of the equipment;

c) ensure the proper condition of the means of protection against static electricity, grounding devices;

d) ensure the normal operation of ventilation systems;

e) comply with work and safety instructions;

e) observe personal hygiene measures;

g) correctly apply overalls, use personal protective equipment, a gas mask with a box brand "BKF";

h) it is not allowed to work on equipment with disconnected or faulty instrumentation and control equipment;

i) comply with the rules for conducting gas hazardous and hot work;

j) flange connections and pipelines with toxic and corrosive substances must have protective covers;

k) it is not allowed to carry out repair work on operating equipment and pipelines.

Safe Handling Practices for Basic Products

Do not allow overflow of hydrogen peroxide, calcium peroxide suspension when taking them into containers, spilling onto the floor. Clean up spilled food immediately.

Do not allow storage of raw materials and finished products in violation of the rules on the incompatibility of chemical products.

Wash off spilled hydrogen peroxide with water, collect spilled calcium hydroxide or building lime with a shovel.

Do not allow violations of the tightness of natural gas pipelines, if there is a smell of gas in the room, open windows and doors.

Prevention in order to exclude poisoning is provided by:

1. Sealing equipment and communications.

2. The operation of ventilation systems.

3. Compliance with work instructions and safety instructions.

4. The use of overalls, the use of personal protective equipment.

5. Compliance with personal hygiene measures (shower after the shift), regular washing of overalls and reduced working hours, as well as increased vacation.

6. Sanitary control over the state of production and air, industrial effluents and emissions.

Individual and collective protective equipment for workers

Shop workers are provided with overalls, special footwear and protective equipment in accordance with the approved norms and terms of wear.

While at the workplace, the employee must be dressed in working clothes prescribed by the norms and have the prescribed protective equipment with him: a filtering gas mask with a BKF brand box, goggles, a helmet, gloves, a respirator.

All shop personnel are required to use collective protective equipment.

Collective means of protection include: ventilation system, grounding of electrical equipment, protective devices, automatic control and alarm devices, safety signs.

ESD Protection Measures

1. All metal parts technological equipment must be grounded.

2. When loading and unloading bulk materials (in and out of plastic bags), use scoops that do not give a spark. Loading by pouring out of plastic bags is not allowed.

Measures to prevent pops and explosions in gas ovens

In order to avoid pops and explosions in gas stoves, it is necessary to use the correct methods for lighting the stove. After turning on the fans 0 - 82a,b and 0 - 81a,b, ventilate the furnace for 10 - 15 minutes, at the same time purge the gas panel of the furnace. At the end of the purge of the cut-off valve, close and switch the remote control panel of the valve to position "A" (automatic), close the valve G - 28. The oven is ready for ignition.

Do not allow natural gas leaks, eliminate leaks and ventilate the room by opening doors and windows.

Measures to prevent dust in the working room with calcium peroxide dust

In order to prevent dustiness of the working room at the stage and preparation of the final form of calcium peroxide, the units are not allowed to operate with a leaky system.

To ensure safety when working with calcium peroxide, the room must be provided with supply and exhaust ventilation with suction in places of possible dusting.

When sampling, testing and applying peroxide, measures must be taken to prevent dusting of the product. Personal protective equipment (respirator, goggles, rubber gloves, overalls) should be used to prevent calcium peroxide from getting on the skin. Mucous membranes and dust penetration into the respiratory and digestive organs, as well as observe personal hygiene measures.

Measures to prevent chemical burns

In order to avoid chemical burns with hydrogen peroxide, calcium hydroxide, calcium peroxide, reaction masses when crushing reaction masses, sampling, measuring the level in apparatuses, loading raw materials into an open hatch - all these works should be carried out in good overalls, goggles or a gas mask.

Measures to prevent thermal burns

To avoid thermal burns, all steam lines must have reliable thermal insulation.

Measures to ensure the reliability of the protection of water resources and the air basin in the event of an emergency

In case of failure of the filtrate and rinsing water collector installed at the workshop site, the leaked filtrate and rinsing water are collected in a pan and pumped to another filtrate collector by a submersible pump.

Rules for acceptance, storage, storage and transportation of raw materials and finished products

1. Raw materials are allowed into production based on the results of input control, carried out in accordance with the requirements of the JSC Khimprom standard STP 35 - 98 "Input control". Acceptance of inorganic and liquid raw materials to the workshop is set out in the technological regulations No. 162 - A "Preparation of inorganic raw materials and operation of auxiliary equipment."

2. For each batch of raw materials entering the workshop, there must be a passport where the main indicators of the product are recorded, compliance with TU or GOST for this product. In addition, before loading into production, a sample is taken from each batch and the workshop laboratory analyzes the incoming raw materials for compliance with TU or GOST.

Raw materials that do not comply with TU or GOST are not allowed into production.

3. Warehousing, storage and transportation of raw materials and the finished product is carried out in accordance with the requirements set forth in the TU or GOST for each type of raw material. Raw materials in the workshop are stored in quantities (not more than) provided for by the norms for the storage of raw materials in the workshop.

4. The product is transported by all means of transport in accordance with the rules for the carriage of goods in force for this type of transport under conditions that ensure the safety of the container and the product. During transportation, the container should not be subjected to impacts.

Conclusion

Calcium peroxide CaO 2 has been known to chemists for a long time: the first detailed study of this substance was carried out in 1810 by the French chemist J. Gay-Lussac. Calcium peroxide is one of the few peroxide compounds that finds a variety of uses. Peroxide compositions based on CaO 2 usually contain 30--70% (mass.) of the main substance, the rest - CaCO 3 and/or Ca(OH) 2 in a mixture with natural binding agents and fillers. Calcium peroxide is usually applied as a solid composition, the slow decomposition of which over a long time leads to the release of hydrogen peroxide, calcium hydroxide and active oxygen:

CaO 2 + 2H 2 O > Ca(OH) 2 + H 2 O 2 2H 2 O 2 > 2H 2 O + O 2

The presence of these decomposition products (H 2 O 2 and O 2) contributes to the development of a number of oxidative processes, on which the widespread use of CaO 2 in practice is based (bleaching, discoloration, elimination of bad odors, local disinfectant effect, etc.). In addition, the formation of calcium hydroxide helps to neutralize unwanted acids.

The increased interest in calcium peroxide is explained not so much by the specifics of its action, but by the environmental safety of the end products of its transformation (CaCO 3 , O 2 , H 2 O), namely, this aspect of the use of chemicals has recently received close attention.

The preparative method for obtaining calcium peroxide has been known since the beginning of the 19th century. Usually, CaO 2 is isolated from CaO 2 ?8H 2 O octahydrate by careful heating at a temperature of? 130 ° C. Calcium peroxide octahydrate itself is synthesized as follows: CaCl 2 ?6H 2 O is dissolved in a small amount of water and treated with a 3% solution of H 2 O 2, 25% aqueous ammonia is added to the resulting solution.

Octahydrate CaO 2 ⋅ 8H 2 O is a white shiny crystals that become opaque in air under the action of carbon dioxide with the formation of the corresponding carbonates. Hydrate CaO2?8H2O hydrolyzes in water, does not dissolve in absolute alcohol and ether.

In the anhydrous state, CaO 2 can be obtained by direct precipitation from a solution of CaCl 2 ⋅ 6H 2 O in 3% hydrogen peroxide by treatment with 25% aqueous ammonia.

Calcium peroxide CaO 2 - tetragonal white crystals, odorless, has the following basic physical and chemical characteristics: decomposes at a temperature of 275 ° C; bulk density? 600 kg/m3; solubility in water at 20 °C?1, 65 g/l; pH of a saturated solution at 20 °C 12.3; at a concentration of 75% (mass.) the content of active oxygen is about 17%.

Modern production of calcium peroxide is based mainly on methods claimed in patents. B proposes a method based on the interaction of a CaCl 2 solution with a 10% NaOH solution and a 30% H 2 O 2 solution; the NaOH solution may additionally contain 6-10 wt. % NaCl. The precipitate formed is filtered off, washed with water, and dried at 125°C. The content of CaO 2 in the resulting product 81--88%(mass.), the yield of hydrogen peroxide 76--90%(mass.).

Calcium peroxide can also be obtained in another way - by direct interaction of calcium hydroxide and a 50% hydrogen peroxide solution:

Ca (OH) 2 + H 2 O 2 > CaO 2 + 2H 2 O

The use of building lime as a feedstock significantly reduces the cost of the final product. Isolation and purification of the target product is carried out at a temperature of 50--60 °C. The product is obtained in the form of a powder (particle size no more than 0.5 microns), which can then be formed into tablets or granules of any desired shape. The content of the target product reaches 60% (usually 40-50%). The product does not contain impurities of heavy metals in environmentally unacceptable amounts. The main impurities that are included in CaO2 when it is obtained by this new method are environmentally friendly substances - calcium carbonate and calcium aluminosilicate. These impurities are present either in the original product or are the result of side processes.

Produced and widely used in European countries, calcium peroxide has the following classification and certification indices:

CAS--1305-79-9; EINECS -- 215-139-4; TSCA -- R117-7967.

Unfortunately, in Russia, calcium peroxide is not as widely used as in countries Western Europe. Therefore, the main purpose of this work is to review the most interesting applications of CaO 2 .

As noted above, the use of calcium peroxide, as well as hydrogen peroxide, is mainly associated with the environmental aspect of its action (oxygen generation, oxidizing and neutralizing abilities). Accordingly, the use of CaO 2 has an ecological and sanitary-hygienic orientation (bleaching, deodorization, disinfection, aeration, etc.). The undoubted advantage of CaO 2 is its increased stability and longer shelf life compared to other peroxide compounds. The main areas of application of calcium peroxide are shown in fig. one.

Calcium peroxide is introduced into pharmaceuticals and cosmetics. It is part of toothpastes - it helps to remove residual food particles from the oral cavity, prevents the formation of tartar, and in combination with Ca (OH) 2 provides a more effective neutralization of food acids. In particular, calcium peroxide is part of the Tooth white toothpaste, which has an intense whitening effect. In addition to CaO2, this paste contains glycerin, calcium carbonate, silicon dioxide, titanium dioxide, sodium lauryl sulfate and flavors. Clinical studies have confirmed the high whitening power of the products of this line - the teeth are lightened by 2-3 tones. Active oxygen contained in calcium peroxide eliminates bacteria that contribute to bad breath.

The composition of the drug "Sunsmile" (chewable tablets) includes calcium peroxide (together with xylitol, sorbitol, potassium bicarbonate, citric acid, silicon dioxide, hydroxypropyl cellulose, etc.). This drug has a tonic effect and freshens breath.

Another area of application of the CaO 2 preparation is associated with agricultural work in summer cottages and garden plots and with growing plants at home. The main effect of CaO 2 in this case is reduced to aeration (oxidation) of the soil, which improves root germination and accelerates the adaptation of transplanted plants. Frequent and abundant watering of plants does not particularly affect the "performance" of CaO 2 due to its low solubility in water.

CaO 2 peroxide accelerates the biological decomposition of waste products of plant and animal origin and significantly reduces the unpleasant odor when the waste rots. Therefore, the addition of CaO 2 to the so-called compost pits is effective - in the presence of CaO 2, the decay of grass and leaves is accelerated. In this case, CaO 2 is used in the form of tablets (in order to prolong the action of CaO 2 during the entire period of decay) in an amount usually not exceeding 1--2% by weight of the primary compost material. The acceleration of decay is achieved due to the almost complete exclusion of the formation of anaerobic zones, in which the process of decay is significantly slowed down. CaO2 introduced into the soil simultaneously has a disinfecting and fungicidal effect (due to hydrogen peroxide released during CaO2 transformations) on toxins formed during plant decay. The introduction of CaO2 also makes it possible to regulate pH by entering the soil with another product, Ca(OH)2.

In some countries, in particular in the USA, calcium peroxide is added to the dough when baking bread products.

The amount of this additive is usually 0.001--0.004% (mass.), Its introduction improves the texture of bread, increases the shelf life of bread, and maintains its softness for a long time.

The introduction of calcium peroxide additives into bakery products is recommended in Russia by the State Research Institute of the Baking Industry.

This drug belongs (along with benzoyl peroxide, perborates, persulfates, ascorbic acid, etc.) to improvers of oxidative action. A feature of oxidizing improvers is their ability to regulate the rheological properties of the dough by strengthening the structure of the dough, inactivating proteinase and activating proteolysis. As a result of these processes, the gas and shape-retaining ability of the dough increases, the volume of baked bread increases, the spreading of hearth products decreases, and the bread crumb becomes whiter. The doses of oxidative type improvers, depending on the specific type of these substances, vary over a wide range: from 0.0004 to 0.02% (wt.) in relation to the mass of flour. Calcium peroxide, fortified with food enzymes and vitamins, has been reported to be a natural supplement to the daily diet. Calcium peroxide is used as an additive not only in baking bakery products, but also in the manufacture of biscuits. Aspects of industrial production and use of complex baking improvers, including CaO2, are considered in the work.

The synthesized CaO2 was assessed for compliance with environmental standards in terms of the content of heavy metals and other elements by elemental and isotopic analysis with ionization in inductively coupled plasma using a VG PLASMA QUAD PQ 2-TURBO device (made in the USA).

This method makes it possible to determine the concentrations of elements and isotopes at the level of 10-9 g/ml. The results of determining the content of elemental impurities in the synthesized CaO2 are shown in Figs. 2.

The analysis showed that the content of elements does not exceed the MPC level. The only exception is aluminum (marked with an asterisk in Fig. 2), the amount of which slightly exceeds the required level. Elements such as P, Mn, Fe, Ni, Co, Cu, As, Te were not found in the sample.

In many European countries, there are no fundamental quantitative restrictions on the addition of CaO2 to food products. For example, CaO2 is added to the feed for laying hens, which leads to a cumulative effect: oxygen and calcium enter the body of the hens - components necessary for the production of eggs and for the disinfection of feed.

Another industrial application of calcium peroxide is its introduction into the composition of sealants (for example, polysulfide ones) as a vulcanization activator. The action of the peroxide introduced into the anhydrous sealant mixture, in this case, is based on the fact that it adsorbs atmospheric moisture, which initiates the vulcanization process. Typically, such sealants include 5--15 wt. including CaO2 (with the content of the main component of about 75%) per 100 wt. h. polysulfide polymer (including additives of plasticizers, etc.). Sealants containing CaO2 can be compounded and colored with other components. At normal temperature and air humidity, the sealant cures from the surface within 24 hours after application, full cure is achieved in 2-4 weeks.

Calcium peroxide is used as a source of oxygen in aluminothermic and other metallurgical processes. Additives of CaO2 make it possible to regulate the temperature regime of the process, make it easier to separate the slag from the metal, and help to reduce defects in the product.

Calcium peroxide has a wide range of applications in the field of environmental protection from pollution to solve specific engineering problems. For example, calcium peroxide can be successfully used to oxygenate drinking water and to remove mucus on filters designed for water purification. At the same time, foul-smelling substances are removed. The use of CaO2 in water treatment systems effectively removes iron, manganese and some other metal cations from water. Therefore, it is very promising to use CaO2 as part of an adsorbent (activated carbon with other additives) for direct purification of drinking water.

No less promising is the use of CaO2 tablets (or other solid forms) for saturating the lower (profundal) layers of artificial or natural reservoirs with oxygen. Aeration is usually used for this purpose, however, this often leads to unsatisfactory results due to excessive mixing, moving nutrients to the surface, which initiates the growth of algae. In contrast to this method, CaO2 tablets, sinking to the bottom of the reservoir and gradually generating oxygen, provide a more satisfactory mode of oxygen saturation of the lower layers. It is this principle of action of CaO2 that was used in due time to clean Lake Geneva from red algae, which multiply most intensively under anaerobic conditions.

The use of CaO2 for water aeration makes it possible to additionally purify water from unwanted ions, such as fluoride ions, by forming compounds that are poorly soluble in water.

It is known the use of calcium peroxide in the biological purification of soil contaminated with oil. The degree of soil purification from oil pollution with the combined action of the biosorbent "S-Verad" and CaO2 is 70--72% in three months, which in natural conditions is achieved only after 1.5 years.

It is promising to use CaO2 simultaneously as an alkaline and peroxide agent for chlorine-free bleaching of waste paper. The bleaching technology makes it possible to achieve pulp whiteness of 88-90% and significantly reduce water consumption (from 100-150 m3 to 10-20 m3 per 1 ton of pulp). The use of CaO2 makes it possible to at least partially replace the expensive NaOH used as an alkaline additive in this process.

When working with CaO2, certain precautions must be observed. The drug should be stored in a cool, dry place, preferably in airtight containers. According to the UN list (list of potentially hazardous substances), calcium peroxide belongs to hazard class 5.1 and can be allowed for transportation by road.

If fairly simple precautions are applied - storage in special containers at a temperature not exceeding room temperature, and protection from moisture and pollution, then CaO2 can be stored for two years without noticeable loss of activity. It is allowed to store calcium peroxide in the amount of 25 kg in paper or polypropylene bags with a polyethylene liner or in double polyethylene bags. In this case, the product is stored in the manufacturer's packaging in covered warehouses at a temperature not exceeding 40 °C in conditions that exclude direct sunlight. Warranty period of storage is 6 months. Under the action of water vapor, oxygen is lost and Ca (OH) 2 is formed. When mixing CaO2 with other substances, it must be ensured that these substances do not have catalytic activity towards CaO2 or reducing activity under the conditions of use. Otherwise, these operations can lead to a rapid decomposition of CaO2, an increase in pressure and a possible explosion, and, if a large amount of oxygen is formed, to ignition. Mixing CaO2 with organic products can increase the potential risk when working with calcium peroxide.

A wide range of possible applications of CaO2 and the environmental safety of its decay products create unconditional prerequisites for a wider production and use of this drug. In conclusion, we note that calcium peroxide is produced at the Cheboksary chemical plant (by order).

Bibliography

1. Guide to preparative inorganic chemistry. Ed. G. Bauer. M.: Izdatinlit, 1956, p. 440.

2. Auth. certificate USSR No. 153254 MPK S01V 15/043, 1989.

3. Auth. certificate USSR No. 421621 IPC S01V 15/04, 1971.

4. Auth. certificate USSR No. 1281507 IPC S01V 15/043, 1986.

5. Russian patent No. 2069171 m.cl. C01B 15/04, 1994.

6. Russian patent No. 2006115939, IPC S01V 15/043, 2007.

7. http://www.ark-inform.com

8. http://www.kolobok.biz

9. http://rusbiz.net

10. http://www.babyton.ru

11. Polandova R.D., Whitehest B. Problems of industrial production of complex bakery improvers...

Substance type

Until 2010, E 930 was included in the group of substances that improve the quality of flour and bread.

Calcium peroxide is an inorganic product, an active compound of oxygen and calcium. There are several ways to get the supplement. In industry, the most common method is the interaction of a 50% hydrogen peroxide solution with a suspension (slaked lime).

The reaction proceeds at a temperature of 25–30ºC; at the final stage, the resulting mass is dried by spraying.

Properties

Package

Additive E 930 is packaged in multilayer paper or polypropylene bags with an inner liner of unstabilized polyethylene. It is allowed to pack the product in tight double plastic bags.

To prevent loss of activity, the product is stored tightly packed at a temperature below 40ºC.

Application

Calcium peroxide in food production performed the technological function of a flour and bread improver. The introduction of not more than 50 mg/kg of an oxidizing additive allows:

increase the rheological properties of the dough (elasticity, viscosity and other indicators);
get a lighter and more porous crumb;
reduce the acidity of bread;
increase the volume of the finished product;
extend the shelf life.

Additions to SanPiN 2.3.2.1293-03 of 2010 excluded the product from the list of approved food products. The substance destroys vitamins, folic acid and other nutrients.

The ability of calcium peroxide to slowly decompose with the release of active oxygen, hydrogen peroxide and calcium hydroxide forms a number of useful qualities of the E 930 additive:

disinfectant action;
high whitening properties;
elimination of unpleasant odors;
providing natural aeration;
neutralization of a number of acids.

All this has found application in various fields of human activity.

Cosmetics and pharmaceutical industries

Additive E 930 as an active ingredient is included in the composition of dental products with an intense whitening effect (for example, Plus White, USA).

calcium peroxide:

neutralizes the destructive effect of food acids;
reduces the likelihood of tartar formation;
stops the reproduction of pathogenic bacteria;
freshens breath.

The disinfectant properties of the additive are used by manufacturers of shaving gels.

Calcium peroxide can be found in antibacterial creams and ointments. medical purpose.

Poultry, livestock

The food additive E 930 has been actively used in industrial poultry farming since the middle of the last century.

The additive protects feed from infection with putrefactive bacteria, prolongs the shelf life.

Numerous studies have proven the benefits of the additive in raising broiler chickens. Introduction to the diet of calcium peroxide:

favorably affects the development of young animals, accelerates growth;
increases the percentage of bird safety in cage and floor keeping;
contributes to the increase in body weight.

Additive E 930 helps to combat mass bird pecking, a behavioral disorder that causes serious economic damage.

Calcium peroxide is in demand at the stage of growing young cows and pigs as a mineral and antibacterial drug with a high antidiarrheal effect. The use of the substance allows you to save livestock, increase weight gain.

Agricultural sector

Additive E 930 is an environmentally friendly soil aerator. The substance saturates the earth with oxygen, prevents its acidification.

Application of calcium peroxide:

increases soil fertility;

strengthens the root system of plants;
increases the adaptation of crops to a new place during transplantation;
accelerates growth;

The product has a fungicidal effect. It is active against the golden potato nematode - the main reason for the decrease in potato yields.

Calcium peroxide is added to compost pits to speed up the biodegradation process. An important factor in this case is the ability of a substance to decompose toxic products of decay, to prevent the occurrence of an unpleasant odor.

Benefit and harm

Ingestion of the E 930 supplement is generally safe for health. The exclusion from the list of permitted substances is due to the property of the substance to destroy vitamins, folic acid and other useful ingredients that are part of food products.

Harm is caused by direct contact with calcium peroxide (for example, in poultry farming or agricultural work). The product is a strong allergen. In case of contact with the skin, it causes irritation, burning, itching.

Inhalation of calcium peroxide is dangerous for the development of the following complications:

dyspnea;
swelling of mucous membranes;
bronchospasm.

When working with the product, personal protective equipment is required: gloves, respirator.

Main manufacturers

The largest Russian manufacturer of the E 930 additive is UniPeK Research and Production Association (Nizhny Novgorod Region). The enterprise produces calcium peroxide under the trade name Kosoks.

Leading global manufacturers:

SOLVAY Chemicals (Belgium);
Shangyu Jiehua Chemical Co., Ltd (China).

Interesting fact! Calcium peroxide increases the shelf life of cut flowers. The substance added to the water releases active oxygen for 20 days, preventing the growth of bacteria and putrefactive microflora.

calcium peroxide- a food additive used as an improver of flour and bread. This additive is registered under the code E-930. Currently food anti-flaming E-930 calcium peroxide used as a food improver of flour mainly in the post-Soviet countries. Most other states, for example, members of the European Union, as well as the United States and Canada, have long excluded this additive from the list of approved for use in production processes. Food Industry.

Application

calcium peroxide It is mainly used in the food industry as a bread quality improver. E-930 added to flour, which subsequently does not require any special storage conditions, before the start of the kneading process calcium peroxide practically does not interact with flour. The optimal dose of the additive does not exceed 20 mg per 1 kg of flour. calcium peroxide allows you to significantly improve the gas-retaining properties of the dough, increase its physical performance, positively affects the quality, reduces the acidity of bread. The fact is that calcium peroxide can significantly improve both the taste and consumer qualities of bread and other bakery products. Often it is used as a flour bleaching agent. Besides E-930 used as a baking powder and baking powder, which is able to significantly increase the volume of the dough, as well as improve the quality of the finished bread.

Impact on the human body

Food supplement E-930 has, in addition to explosiveness and flammability, a number of contraindications and side effects. The negative qualities of calcium peroxide include its high allergenicity. Contact with E-930 often leads to severe irritation of the skin, mucous membranes, redness, peeling, itching, burning. If a suspension of calcium peroxide enters the respiratory tract, irritation of the respiratory organs, an asthmatic attack, shortness of breath, and complications during inhalation and exhalation develop. When using products containing this nutritional supplement, no complications were noted in the control group of people.

Application Precautions

Explosive in contact with flammable substances
Irritates mucous membranes
Causes respiratory irritation
Irritates the skin (hyperallergen)
Physicochemical characteristics

According to its chemical structure and distinctive parameters, food antiflaming E-930 calcium peroxide is nothing more than an inorganic and at the same time a binary compound, which is obtained as a result of the interaction of oxygen, as well as calcium. By their appearance calcium peroxide- This is a powdered compound that is absolutely insoluble in the aquatic environment. In the food industry calcium peroxide obtained by the action of hydrogen peroxide on calcium hydroxide, which, as a rule, is a suspension. E-930 organically active compound. calcium peroxide decomposes at a temperature of 250C. In addition, when interacting with hot water (the temperature should not be lower than 50C), it begins to gradually slowly decompose. Also, food antiflaming interacts with various acids. Its main feature is that the compound can ignite spontaneously under certain conditions. For example, if you mix E-930 calcium peroxide and the substance of organic origin explosion will be inevitable. However, despite such features, this additive is produced in thousands of tons annually. Plus, it is used in the food industry.

calcium peroxide application. Method for producing calcium peroxide

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