Application of calcium peroxide in poultry farming. Method for producing calcium peroxide. Cosmetics and pharmaceutical industries

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

Agricultural sector

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

Adding 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. Shows activity against golden potato nematode - the main cause of reduced potato yields.

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

Benefits and harms

Ingestion of the E 930 supplement is generally safe for health. Exclusion from the list of permitted substances is due to the property of the substance to destroy vitamins, folic acid and other beneficial ingredients included in food products.

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

Inhalation of calcium peroxide is dangerous due to the development of the following complications:

• dyspnea;
• swelling of the 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 the UniPeK research and production association (Nizhny Novgorod region). The company 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 preservation of cut flowers. The substance added to water releases active oxygen for 20 days, preventing the proliferation of bacteria and putrefactive microflora.

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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"

Chemical-Pharmaceutical Faculty

Department of Chemical Technology and Environmental Protection

on educational (introductory) practice

on the topic: Calcium peroxide production technology

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

Checked by: SST Specialist of Khimprom OJSC Gorbushkina A.N.

Cheboksary 2014

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

Conclusion

List of used literature

General information about the enterprise, organization, structural unit

OJSC "Khimprom" is one of the key enterprises of the domestic chemical industry, whose activities are focused on large-scale 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, and 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 thermal power engineering, oil production and oil refining industries.

The plant is developing Russia's largest production of hydrogen peroxide, which meets international standards and meets the needs of the textile and pulp and paper industries for 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, and service for its customers. Therefore, the company and our products have a good reputation in Russia and abroad: 20% of supplies are exported to 28 countries. The company's quality management system has been tested and found to comply with the requirements of the ISO 9001:2008 standard.

Characteristics of raw materials, materials and manufactured products

Name of production - calcium peroxide (percalcite).

Percalcite production is located in building 602a. Year of commissioning - 1994. Design production capacity - 1000 tons. Achieved production capacity - 453 tons. Production method - periodic. Single-fuel production.

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 Center 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 it, 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. it contains 95.6% calcium compounds, which in terms of CaCO3 is 50% more effective than the best varieties 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 technology. Increases yield up to 20%. Has nematicidal properties. When disinfecting protected soil from root-knot nematodes, it is equivalent to vidat. Provides localization and elimination of foci of root-knot nematode infection without steaming or treating the soil with methyl bromide; the cost of treatment with the drug is 2-4 times less than when using steaming or methyl bromide.

Structural formula

Empirical formula of CaO 2

Molecular weight - 72.08

Basic physical and chemical properties

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

Application

Characteristics of feedstock, materials and intermediate products

Raw materials are allowed into production based on the results of incoming inspection performed in accordance with the requirements of the Khimprom OJSC enterprise standard STP - 35 - 98 “Incoming inspection of raw materials”.

General production flow diagram and brief description of the technological process

Ca hydroxide

hydrogen peroxide

washing losses

hot air

packaging 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 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 diagram and technological process of one of the stages

Description of the technological process

1. Obtaining condensate

Steam from the main pipeline is supplied to a shell-and-tube heat exchanger, cooled by circulating water. Steam condensate from the heat exchanger enters the storage tank. The apparatus is steel, enameled, with a capacity of 3200 dm 3, equipped with an anchor mixer 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 dm 3, 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 from the apparatus is loaded into the apparatus (the level in dm is controlled by a certified meter rod), the mixer is turned on and calcium hydroxide weighing 1700.9 kg (in terms of 100% product) is loaded through the hatch of the apparatus. To capture calcium hydroxide, air containing calcium hydroxide dust is passed through a scrubber filled with water. By feeding 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 into a suspension of calcium hydroxide into the apparatus at a temperature of 25-30 0 C within 1-3 hours. After loading of hydrogen peroxide is completed, the percalcite suspension is cooled to a temperature of at least 15 0 C and transferred with compressed air at a pressure of no more than 0.3 MPa at the drying stage into a pressure tank.

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

4. Drying calcium peroxide suspension

Percalcite is dried using a spray dryer. Before drying begins, water is poured into the scrubber reducing device 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 the temperature has stabilized, the dryer is switched to the percalcite suspension drying mode.

The temperature of the gas-air mixture at the outlet of the dryer is 180:210 0 C. The temperature of the exhaust gases at the outlet of the dryer is 105:120 0 C.

A percalcite suspension from a pressure tank is supplied to the spray turbine by a monopump and sprayed into a drying chamber in a stream of hot air.

Dried percalcite settles on the walls of the conical bottom, from which it is shaken off using electromagnetic hammers on the bottom of the dryer. Through a sector feeder, percalcite enters a receiving hopper installed on a strain gauge 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 a fan with a vibrator into the hopper; the other part of the percalcite with air from the cyclone enters the wet scrubber, where the air is purified from a recirculating device and released into the atmosphere.

During the drying process, water from the scrubbers, as it becomes saturated with calcium peroxide (mass concentration of calcium peroxide more than 20 g/dm 3 from the recirculating device, is periodically drained into the collection of scrubber liquid, and from there, as it accumulates, it is pumped by a vortex pump into a pressure tank and then for drying. Output of percalcite 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 belt-type batch mixer designed for mixing bulk materials with liquid components, averaging heterogeneous in appearance, content of the main substance, substances with a capacity of 10,000 dm 3 with a ripper rotor speed of 0.33 rpm, equipped with a mechanized loading and unloading, fill factor 0.4-0.7.

To average the quality of the product, dried percalcite is loaded into the mixer from a 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 stirring, turn off the mixer drive and take 2-3 samples from different points of the mixer using a screw feeder and unload them into containers marked in accordance with GOST 6732-4 with the application of manipulation signs “temperature limit” and “Take care” from moisture" according to GOST 14192, classified code 5113 and danger sign according to GOST 19433 and an additional inscription "Protect from impact". Net weight 25-30 kg.

The packaging area is equipped with platform technological scales, model RP - 150 - 13C, GOST. The product is analyzed for all indicators. Finished products are assembled into batches.

If the analysis result is negative, the percalcite quality 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 theoretical yield, based on calcium hydroxide, is: 62.68%

Technological standards, production control

Technological standards

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

Production control and process control

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

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

Waste generation standards (per 1 ton of product) production

Occupational health and safety

Main production hazards

In the production of calcium peroxide, the main hazards are: 1. Thermal burn by steam due to loose flange connections of the fittings when producing steam condensate.

2. Electric shock.

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

4. Possibility of chemical burns to the skin due to construction lime, hydrogen peroxide, or reaction mixture during squeezing, sampling, measuring the level in the apparatus, or loading raw materials into an open hatch.

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

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

7. Possibility of explosion due to the formation of explosive mixtures of natural gas with air.

8. Violation of safety rules by workers.

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

Stopping of equipment and communications is carried out on the basis of a written order from the workshop manager in accordance with the schedule.

During a planned shutdown of production, equipment must be cleaned of dirt and sludge, rendered harmless, and washed. After which an analysis must be performed to determine the content of harmful substances and explosion hazards.

If the analysis result is positive, the equipment is deafened from all communications using standard plugs and de-energized.

The equipment is prepared for repair by operating personnel under the guidance of the shift foreman.

The date, time, place of installation of each plug, time of removal, as well as the names of the workers who installed and removed it, the name of the person on whose instructions the plug was removed or installed, are recorded in a special journal “Log of Installation and Removal of Plugs.”

Opening the device or disconnecting the pipeline should only be done in the presence of a representative of the workshop administration. The person responsible for bringing equipment out for repairs is obliged to provide ventilation in the workshop to eliminate the possibility of flammable and toxic gases appearing at repair workstations.

When bringing equipment 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 “Instructions for organizing the safe conduct of gas-hazardous work at Khimprom OJSC” (TB - 16). When repairing equipment, the safety rules set out 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 devices and critical communications

The specific task for stopping 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 the event of a fire, call 01 or call the fire detector and begin extinguishing the fire using primary fire extinguishing agents.

If there is gas pollution, open windows and doors and notify the SSIA by phone 0 - 4; 54 - 24.

Stop 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 technological process, inform the shift foreman, do not turn on or 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 launching, it is necessary to carefully check all devices, open their hatches, make sure that there are no foreign objects or liquids in them, and tightly close the hatch covers;

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

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

Check the correct rotation of mixers and pumps;

Check the proper functioning of the instrumentation and control systems;

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

Make sure that general exchange ventilation and local suction are working;

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

Safety measures when conducting the technological process and performing routine production operations

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

a) prevent equipment from overflowing and products from entering the production area;

b) ensure reliable tightness of the equipment;

c) ensure the proper condition of protective equipment against static electricity and grounding devices;

d) ensure normal operation of ventilation systems;

e) comply with work and safety instructions;

f) observe personal hygiene measures;

g) correctly use protective clothing, use personal protective equipment, a gas mask with a box of the “BKF” brand;

h) it is not permitted to work on equipment with disconnected or faulty instrumentation and automation devices;

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

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

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

Safe handling practices for essential products

Do not allow hydrogen peroxide or calcium peroxide suspension to overflow when taken in containers or spill onto the floor. Clean up any accidentally spilled food immediately.

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

Wash off spilled hydrogen peroxide with water, and scoop up spilled calcium hydroxide or building lime with a scoop.

Avoid leaking natural gas pipelines; if there is a smell of gas in the room, open windows and doors.

Prevention to prevent poisoning is provided by:

1. Sealing of equipment and communications.

2. Operation of ventilation systems.

3. Compliance with work instructions and safety instructions.

4. The use of special clothing, the use of personal protective equipment.

5. Compliance with personal hygiene measures (shower after shift), regular washing of work clothes and shortened working hours, as well as increased vacation.

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

Individual and collective means of protection for workers

Shop workers are provided with special clothing, special footwear and protective equipment in accordance with approved standards and wearing periods.

While at the workplace, the employee must be dressed in proper working clothing in accordance with the standards and have with him the required protective equipment: a filtering gas mask with a box of the BKF brand, goggles, a helmet, gloves, a respirator.

All workshop personnel are required to use collective protective equipment.

Collective protective equipment includes: ventilation system, grounding of electrical equipment, fencing devices, automatic control and alarm devices, safety signs.

Anti-static precautions

1. All metal parts of process equipment must be grounded.

2. When loading and unloading bulk materials (into and out of plastic bags), use non-sparking scoops. Loading by pouring out of plastic bags should not be allowed.

Measures to prevent pops and explosions in gas furnaces

To avoid popping noises and explosions in gas furnaces, you must use proper oven ignition techniques. After turning on fans 0 - 82a,b and 0 - 81a,b, ventilate the firebox for 10 - 15 minutes, while simultaneously purging the gas panel of the stove. At the end of the purging of the cut-off valve, close the valve remote control panel switch to position “A” (automatic), close tap G - 28. The stove is ready for ignition.

Avoid leaks of natural gas, eliminate leaks and ventilate the room by opening doors and windows.

Measures to prevent dust contamination of the working area with calcium peroxide dust

In order to prevent dust in the working area at the stage and prepare the release form of calcium peroxide, the operation of units with a leaky system is not allowed.

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

When sampling, testing and using peroxide, measures must be taken to prevent dusting of the product. Personal protective equipment (respirator, safety glasses, rubber gloves, overalls) should be used to prevent calcium peroxide from coming into contact with the skin. Mucous membranes and penetration of dust into the respiratory and digestive organs, and also observe personal hygiene measures.

Measures to prevent chemical burns

To avoid chemical burns from hydrogen peroxide, calcium hydroxide, calcium peroxide, reaction masses when squeezing reaction masses, taking samples, measuring levels in devices, loading raw materials into an open hatch - perform all this work in proper overalls, safety glasses or a gas mask.

Measures to prevent thermal burns

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

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

If the filtrate and wash water collector installed on the shop floor fails, the leaked filtrate and wash water are collected in a pan and pumped into another filtrate collector by a submersible pump.

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

1. Raw materials are allowed into production based on the results of incoming inspection performed in accordance with the requirements of the Khimprom OJSC standard STP 35 - 98 “Incoming inspection”. Acceptance of inorganic and liquid raw materials into the workshop is set out in 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, which records the main indicators of the product, compliance with technical specifications or GOST for this product. In addition, before loading into production, a sample is taken from each batch and the workshop laboratory analyzes whether the received raw materials comply with technical specifications or GOST.

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

3. Warehousing, storage and transportation of raw materials and finished products is carried out in accordance with the requirements set out in the technical specifications or GOST for each type of raw material. Raw materials in the workshop are stored in quantities (no more than) provided for by the standards for storing raw materials in the workshop.

4. The product is transported by all modes 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 product. During transportation, the container should not be subject to shock.

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 has a variety of uses. Peroxide compositions based on CaO 2 usually contain 30-70% (wt.) of the main substance, the rest is CaCO 3 and/or Ca(OH) 2 mixed with natural binding agents and fillers. Calcium peroxide is usually applied in the form of a solid composition, the slow decomposition of which over a long period of 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, which is the basis for the widespread use of CaO 2 in practice (bleaching, bleaching, elimination of bad odors, local disinfection, etc.). In addition, the formation of calcium hydroxide helps 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 final products of its transformation (CaCO 3, O 2, H 2 O), and it is this aspect of the use of chemicals that has received close attention recently.

The preparative method for producing calcium peroxide has been known since the beginning of the 19th century. Typically, CaO 2 is isolated from CaO 2 octahydrate ? 8H 2 O 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, and 25% aqueous ammonia is added to the resulting solution.

Octahydrate CaO 2 ? 8H 2 O is white shiny crystals, which in air become opaque under the influence of carbon dioxide with the formation of the corresponding carbonates. CaO2?8H2O hydrate hydrolyzes in water and is insoluble 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 when treated with 25% aqueous ammonia.

Calcium peroxide CaO 2 - tetragonal white crystals, odorless, has the following basic physicochemical 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 the saturated solution at 20 °C 12.3; at a concentration of 75% (wt.), the active oxygen content is about 17%.

Modern production of calcium peroxide is based mainly on methods stated 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 that forms is filtered off, washed with water, and dried at a temperature of 125 °C. The CaO 2 content in the resulting product is 81--88% (wt.), the yield of hydrogen peroxide is 76--90% (wt.).

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

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

The use of construction lime as a raw material 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 heavy metals in environmentally unacceptable quantities. The main impurities that are included in CaO2 when it is produced by this new method are environmentally friendly substances - calcium carbonate and calcium aluminosilicate. These impurities are either present in the original product or are a consequence of side processes.

Calcium peroxide, produced and widely used in European countries, 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 Western Europe. Therefore, the main goal of this work is to review the most interesting areas of application of CaO 2.

As noted above, the use of calcium peroxide, like 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 environmental 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 applications of calcium peroxide are presented in Fig. 1.

Calcium peroxide is added to pharmaceuticals and cosmetics. It is included in toothpastes - it helps remove residual food particles from the oral cavity, prevents the formation of tartar, and in combination with Ca(OH)2 it provides more effective neutralization of food acids. In particular, calcium peroxide is included in 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 flavoring additives. Clinical studies have confirmed the high whitening ability of the products in this line - teeth are lightened by 2-3 tones. The active oxygen contained in calcium peroxide eliminates bacteria that contribute to bad breath.

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

Another area of ​​application of the CaO 2 drug is associated with agricultural work in summer cottages and gardens 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 of plant and animal origin and significantly reduces the unpleasant odor during rotting waste. Therefore, adding CaO 2 to the so-called compost pits is effective - in the presence of CaO 2, the rotting 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. Acceleration of decay is achieved by almost completely eliminating the formation of anaerobic zones, in which the process of decay is significantly slowed down. CaO2 introduced into the soil simultaneously has a disinfectant and fungicidal effect (due to hydrogen peroxide released during CaO2 transformations) on toxins formed during plant rotting. The introduction of CaO2 also allows you to regulate pH by introducing another product into the soil - Ca(OH)2.

In some countries, particularly 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 baked goods 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 oxidative action improvers. A feature of oxidative action improvers is their ability to regulate the rheological properties of dough by strengthening the dough structure, inactivating proteinase and activating proteolysis. As a result of these processes, the gas and shape-holding 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 improvers, depending on the specific type of these substances, vary widely: from 0.0004 to 0.02% (wt.) relative to the weight of flour. According to data, calcium peroxide fortified with food enzymes and vitamins can serve as a natural supplement to the daily diet. Calcium peroxide is used as an additive not only in baking baked goods, but also in making cookies. Aspects of industrial production and use of complex baking improvers, including CaO2, are discussed in the work.

The assessment of synthesized CaO2 for compliance with environmental standards for the content of heavy metals and other elements was carried out by elemental and isotope 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 a level of 10-9 g/ml. The results of determining the content of elemental impurities in the synthesized CaO2 are shown in Fig. 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 feed for laying hens, which leads to a net effect: oxygen and calcium enter the chickens' body - components necessary for the production of eggs and for disinfection of feed.

Another industrial use of calcium peroxide is its introduction into sealants (for example, polysulfide) as a vulcanization activator. The action of peroxide introduced into the anhydrous mixture of sealant, 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. parts CaO2 (with a content of the main component of about 75%) per 100 wt. including polysulfide polymer (including plasticizer additives, etc.). Sealants containing CaO2 can be compounded and colored with other components. At normal temperature and air humidity, the surface sealant vulcanizes within 24 hours after application, complete vulcanization is achieved after 2-4 weeks.

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

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

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

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

It is known to use 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 S-Verad biosorbent and CaO2 is 70-72% after three months, which under natural conditions is achieved only after 1.5 years.

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

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

If you use fairly simple precautions - storage in special containers at a temperature not exceeding room temperature, and protection from humidity and contamination, then CaO2 can be stored for two years without a noticeable loss of activity. It is allowed to store calcium peroxide in an 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 under conditions excluding direct sunlight. Guaranteed shelf life 6 months. Under the influence of water vapor, oxygen is lost and Ca(OH)2 is formed. When mixing CaO2 with other substances, it is necessary to ensure that these substances do not have catalytic activity towards CaO2 or reducing activity under the conditions of use. Otherwise, these operations can lead to 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 may increase the potential risk when handling calcium peroxide.

The wide range of possible uses of CaO2 and the environmental safety of its decomposition products create absolute prerequisites for wider production and use of this drug. In conclusion, we note that calcium peroxide is produced at the Cheboksary Chemical Plant (on request).

Bibliography

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

2. Auto. date USSR No. 153254 MPK S01V 15/043, 1989.

3. Auto. date USSR No. 421621 MPK S01B 15/04, 1971.

4. Auto. date USSR No. 1281507 MPK S01V 15/043, 1986.

5. Russian patent No. 2069171 m.cl. С01В 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 baking technologies...

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The invention relates to calcium peroxide technology. The method for producing calcium peroxide involves 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. 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 stage, 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 following range: 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 fine calcium peroxide hydrate, and simplify the process chain. 1 salary files, 1 table.

The invention relates to a technology for producing 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 a source of oxygen in the food, perfume industry, agriculture, medicine, household chemicals, etc.

The advantages of CaO 2 compared to other solid carriers of active oxygen are the environmental purity of the final 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.

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

There is a known method for producing calcium peroxide by reacting an aqueous solution of calcium chloride, a 10% NaOH solution and a 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 NaCl content in the solution, and the increased energy consumption for its implementation.

There is a known method 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 of P = 10-10 -2 mm Hg. and an initial temperature of 0-10°C with an increase in temperature during dehydration to 140-160°C. According to another option, 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 calcium peroxide diperoxo solvate is treated with a cooled 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.

There is 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.

There is 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 the diperoxohydrate, as well as the need for its decomposition at low temperatures.

There is a known method for producing calcium peroxide by reacting calcium hydroxide or salts in an alkaline medium with hydrogen peroxide. Oxygen-containing organic substances with a boiling point of no 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 additional purification of the product is required.

The closest to the claimed method is a method for producing calcium peroxide, which includes the interaction of dry calcium hydroxide with an aqueous solution of hydrogen peroxide to form calcium peroxide hydrate and its subsequent thermal dehydration [a.s. USSR No. 1532547, С01В 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 that is subject to strict technological safety requirements, for example, 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 a stage of forced cooling of the reaction mixture and a labor-intensive stage of filtering the fine precipitate of calcium peroxide hydrate.

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

The invention is aimed at finding a method for producing calcium peroxide from quicklime, eliminating the energy-intensive stage of cooling the intermediate product while simultaneously simplifying the entire process 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 thermal stage 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.

It is preferable 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 following range: alkali metal phosphate; ethylenediaminetetraacetic acid; complex of polyethylene glycol with phosphorus (V) oxide.

Reducing energy consumption in the claimed method is achieved by adjustable 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 mole of Ca(OH) 2 per minute is selected from the condition that for all stated 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. The controlled supply of H 2 O 2 solution eliminates the stage of forced cooling of the reaction mixture.

The use of accessible and cheap quicklime - calcium oxide - as a starting reagent significantly expands the raw material base of calcium peroxide technology.

Simplification of the technology is achieved by eliminating the forced cooling of the reaction mixture due to the controlled supply of hydrogen peroxide solution, as well as 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 therefore of calcium peroxide.

Calcium peroxide is prepared 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 ensuring 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 finely dispersed 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 active oxygen content, after which its yield is determined.

Below are examples of implementation of the claimed method.

100 ml of H 2 O is poured into 30 g of CaO over 30 minutes. 42 ml of 35% H 2 O 2 are poured into the resulting suspension at a flow rate of 0.006 mol H 2 O 2 per mole of Ca(OH) 2 per minute. Within 30 minutes, a molar ratio of H 2 O 2:Ca(OH) 2 equal to 1.2 is achieved. The temperature in the reaction zone is maintained within 30-40°C. The precipitate of Ca(OH) 2 with the mother solution is left to settle in the reaction vessel for 2 hours. The compacted sediment 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.

As follows from the data obtained, calcium peroxide with a purity of up to 50 wt.% can be obtained using a solution of hydrogen peroxide 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 makes it possible to expand the raw material base of calcium peroxide technology through the use of quicklime, eliminate the energy-intensive stages of cooling the reaction mixture and filtering fine calcium peroxide hydrate, and simplify 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 feeding 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 range: alkali metal phosphate, ethylenediaminetetraacetic acid, complex of polyethylene glycol with phosphorus (V) oxide.

Other names: calcium peroxide, calcium peroxide, E930.

Receipt Calcium peroxide is prepared from calcium hydroxide and hydrogen peroxide:

• Ca(OH) 2 + H 2 O 2 = CaO 2 + 2H 2 O

Usage E930 is used as a baking improver with oxidative action. Because calcium peroxide is insoluble in water, it is usually added to flour. Treated flour can be stored under the same conditions as regular flour, since the improver does not interact with the flour before kneading. The optimal dosage of the drug depends on the type of flour and its strength, but does not exceed 20 mg/kg of flour. Calcium peroxide improves the physical properties of dough, increases gas retention capacity, increases the quality of bread, and also, unlike other oxidative action improvers (potassium bromate and iodide), reduces the calorie content of bread. The greatest effect can be achieved with a straight method of preparing the dough. When using the sponge method and using liquid semi-finished products, it is appropriate to add the drug not to the flour, but to the dough.

Bibliography

• Lastukhin Yu.A. Nutritional supplements. E-codes. Structure. Receipts. Properties. Textbook manual. - Lviv: Center of Europe, 2009. - 836 p. ISBN 978-966-7022-83-9 (p. 767 - 768)
• Matveeva I.V., Belyavskaya I.G. Food additives and baking improvers in the production of flour products. Second edition, revised and expanded. - M.: 2001. - 116 p. (p. 19)
• Resolution of January 4, 1999 N 12 Kyiv On approval of the list of food additives permitted for use in food products
• Sanitary norms and rules “Requirements for food additives, fragrances and technological aids” APPROVED. Resolution of the Ministry of Health of the Republic of Belarus December 12, 2012 No. 195
• Health Canada. List of Permitted Bleaching, Maturing or Dough Conditioning Agents (Lists of Permitted Food Additives)
• Appendix 1 to SanPiN 2.3.2.1293-03 FOOD ADDITIVES FOR FOOD PRODUCTION