Monocalcium phosphate production process

FIELD: industrial inorganic synthesis.

SUBSTANCE: monocalcium phosphate, widely applied in agriculture, is prepared by mixing extraction phosphoric acid with calcium-containing component followed by granulation and drying of product. During mixing of components, appropriate temperature and moisture are maintained to ensure viscosity of mixture 3-7 mPa*s, and granulation and drying are carried out simultaneously in drum-type granulator drier. Calcium-containing component is either calcium carbonate or mixture thereof with limestone, whose does not exceed 15% of total weight of calcium-containing raw material. Moisture content in worked out drying agent leaving drum-type granulator drier equals 70-80 g per 1 kg dry air.

EFFECT: simplified process flowsheet, enabled granule size control, and increased strength of granules.

3 cl, 3 ex

 

The invention relates to methods of obtaining lokalitetot, widely used in agriculture.

A method of obtaining orthopedically one-deputizing, including evaporation of phosphoric acid to the content of P2About565-67,5%, followed by neutralization of its calcium carbonate. The initial molar ratio of Cao/R2About5equal (0,95-1,0):1. The resulting mass is crushed to particle size of not more than 0.1 mm (Patent RF №2172717, CL 01 In 25/32, 2001).

However, in this method are mostly fine product, which is used in the food industry. Its use as a feed means is quite difficult due to its high piomote and segregation in a mixture with other feed additives and organic feed.

The closest to describing the technical essence and the achieved result is another well-known method of obtaining feed phosphates of calcium (namely, monocalcium phosphate), comprising a mixture of phosphoric acid with calcium-containing component in the presence of retur, granulation and drying of the product.

According to this method, as the calcium-containing component use calcium carbonate or lime. The mixing is conducted at a molar ratio of CA/P, is equal to 1.3 to 1.6. At this stage receive mainly dicalcium phosphate. N the stage of mixing serves part of retur, obtained after the stage of granulation and drying of the product that are organized separately. Granulation are in catachem the drum, and drying in the dryer. External returnest on stage granulating at least 3. Then the dried product is treated with phosphoric acid to obtain phosphate and again carry out the drying at a temperature of 145-170°C. the method can reduce the fluoride content in the product to 0.15-0.2% (A.S. USSR №1463733, CL 01 In 25/32, 1989).

Technologically, the method is quite cumbersome and time consuming as it requires the organization of two stages of mixing and two-stage drying of the product. Output of marketable fractions (pellets with a size of 0.2-2.0 mm) is small and is 55%. Furthermore, the method does not allow the production process to modify and adjust the size of the granules depending on customer requirements.

We have been tasked to create a large-tonnage production of monocalcium phosphate, greatly simplifying this process flow, as well as to obtain granules with adjustable strength and variable grain size (by customer request).

The problem is solved in the proposed method of obtaining phosphate, comprising a mixture of phosphoric acid with calcium-containing component, subsequent granulation and drying of the product. When mixing the components support the temperature and humidity, necessary to obtain a mixture with a dynamic viscosity 3-7 MPa·and granulating and drying the product lead time in the drum granulator-dryer (BGS), if returnest of 0.8-1.2. The moisture content of the drying agent, it is advisable to maintain the level of 70-80 g/kg of dry air. As a calcium-containing component is used or calcium carbonate, or a mixture of lime, which amount in the mixture does not exceed 15% of the total mass of calcium-containing raw materials.

For granulating in one stage in a drum granulator-dryer (BGS), in which the slurry is sprayed on the particles reture to obtain a homogeneous and solid granules, great importance is the viscosity of the mixture supplied to the spray. The required dynamic viscosity (3-7 MPa· (C) is achieved by varying the temperature and humidity of the pulp. The selection of these parameters was carried out on the basis of the following data. The viscosity of the suspension phosphate increases with decreasing humidity and increasing temperature, which leads to salustiano because form supersaturated solutions of phosphate with the formation of very small crystals of the solid phase, capable of holding about a significant amount of liquid. It is also possible participation in the process of thickening of small amounts of silica gel, the resulting p and neutralization. The humidity of the mixture depends on the concentration used phosphoric acid, the dispersion of the calcium-containing component, the amount of added water. The required temperature depending on the conditions of production can be achieved by temperature or the acid, or feedwater, or by heating the mixture. Water is added to the mixture to achieve the required moisture content is introduced either directly on the stage of mixing (mixer), or for an additional stage dilution is carried out after mixing the components. All this is regulated by specific production conditions (the use of certain raw materials, production capacity, availability of reaction equipment).

The dynamic viscosity of the spray mixture should be 3-7 MPa·C. Reducing it worsens the conditions of transport and dispersion, resulting in uneven on the composition and strength of the product. The viscosity increase is impractical because of the deterioration in the distribution of slurry across the surface of the granules, which, of course, violates the homogeneity of the composition. When carrying out the granulation and drying of the product at the same time in the apparatus BGS greatly reduced external returnest process. Thanks to the proposed returnest 0,8-1,2 achieved the ability to control the particle size and coloring strength is I. The moisture content of the drying agent 70-80 g/kg dry air also chosen based on the need to obtain a stable granulometric composition and durable product. The reduction in moisture content will result in reduction of yield of marketable fractions, and the increase to the increase of humidity of the material.

The method involves the use of calcium-containing raw material mixture of calcium carbonate of lime. However, the amount of lime should not exceed 15% of the total mass of calcium-containing raw materials, as due to the growth temperature of decomposition yields polyphosphates, which leads to reduction of digestible phosphorus in the product.

Using the proposed method allows to obtain the phosphate fairly simple process flow. The strength of the pellets is increased from 5 kg/cm2to 36-80 kg/cm2. Depending on customer requirements it is possible to obtain a product with different granule size and strength. Output of marketable fraction is 65-85%.

The method is illustrated by the following examples.

Example 1. 13.5 t/h wet-process phosphoric acid concentration of 25% P2O5mix in the tank neutralizer from 2.9 t/h of calcium carbonate. The temperature of the neutralization is 40°C, humidity pulp - 63%. The result is a slurry containing monocalcium ofat with a viscosity of 3 MPa· C. the Slurry fed to the granulation and drying in a drum granulator-dryer (BGS). The process is conducted at moisture content of the drying agent 80 g/kg of dry air and returnest process to 0.8. The result is to 6.43 t/h phosphate. Output of marketable fractions (pellets with a size of 0.2-2 mm) - 85%. The strength of granules - 36 kgf/cm2.

Example 2. 14.4 tons/hour wet-process phosphoric acid concentration of 26.3% of the P2About5mix in the tank neutralizer from 2.9 t/h of calcium carbonate. The temperature of the neutralization is 45°C, humidity pulp - 61%. The result is a slurry containing monocalcium phosphate with a viscosity of 5 MPa·C. the Slurry fed to the granulation and drying in a drum granulator-dryer (BGS). The process is conducted at moisture content of the drying agent and 75 g/kg of dry air and returnest process - 1. The result 7,56 t/h phosphate. Output of marketable fractions (pellets with a size of 0.2-2 mm) - 70%. The granule strength of 50 kgf/cm2.

Example 3. 14.4 tons/hour wet-process phosphoric acid concentration of 26.3% R2About5mixed with the 2.46 t/h of calcium carbonate and 0.25 t/h lime (9.2% of the total mass of calcium-containing raw materials). The temperature of the neutralization reaction is 50°C, humidity of 55.5%. The viscosity of the obtained slurry of phosphate - 7 MPa. The pulp is fed to the granulation and with whom the Cabinet in the apparatus BGS. The process is conducted at moisture content of the drying agent 70 g/kg of dry air and returnest of 1.0. The result 7,42 t/h. The granule strength of 80 kgf/see the Output of marketable fraction of 72%.

1. The method of obtaining phosphate, comprising a mixture of phosphoric acid with calcium-containing component, subsequent granulation and drying of the product, characterized in that the mixing of the components maintain the temperature and humidity needed to obtain a mixture with a viscosity 3-7 MPa·and granulating and drying the product lead time in the drum granulator-dryer (BGS) returnsthe of 0.8-1.2.

2. The method according to claim 1, characterized in that as the calcium-containing component is used or calcium carbonate, or a mixture of lime, which amount in the mixture does not exceed 15% of the total mass of calcium-containing raw materials.

3. The method according to claim 1, characterized in that the moisture content of the spent drying agent, leaving BGS, 70-80 g/kg of dry air.



 

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FIELD: industrial inorganic synthesis.

SUBSTANCE: monocalcium phosphate, widely applied in agriculture, is prepared by mixing extraction phosphoric acid with calcium-containing component followed by granulation and drying of product. During mixing of components, appropriate temperature and moisture are maintained to ensure viscosity of mixture 3-7 mPa*s, and granulation and drying are carried out simultaneously in drum-type granulator drier. Calcium-containing component is either calcium carbonate or mixture thereof with limestone, whose does not exceed 15% of total weight of calcium-containing raw material. Moisture content in worked out drying agent leaving drum-type granulator drier equals 70-80 g per 1 kg dry air.

EFFECT: simplified process flowsheet, enabled granule size control, and increased strength of granules.

3 cl, 3 ex

FIELD: inorganic chemistry, chemical technology.

SUBSTANCE: invention relates to technology for preparing fodder calcium phosphates, namely to producing monocalcium phosphate. Method involves mixing wet-process phosphoric acid with a calcium-containing component in the presence of recycle, granulation and drying the product. Mixing process is carried out for two stages. At the first stage wet-process phosphoric acid with the concentration 62-65% of P2O5 is fed and process is carried out at recycle index = 1:(0.3-0.5) up to decomposition degree of calcium-containing raw = 0.89-0.92 at this stage. The second stage is combined with granulation and carried out its in high-speed mixer in water addition to obtain moisture in mixture 9.5-13%. The rate and time for mixing are regulated to provide the decomposition degree of calcium-containing raw = 0.93-0.99, and temperature at the next drying stage is maintained in the level 105-115°C. Method provides simplifying the process, reducing energy consumption and preparing product with the high content of P2O5 in water-soluble form and low content of fluorine.

EFFECT: improved method for preparing.

2 cl, 3 ex

FIELD: production of pure phosphoric acid and calcium monohydrophosphate.

SUBSTANCE: proposed method includes decomposition of phosphate ore by first hydrochloric acid solution at concentration not exceeding 10 mass-%, separation of liquid decomposition product into insoluble solid phase containing admixtures and separate aqueous phase containing phosphate, chloride and calcium ions in form of solution, neutralization of aqueous phase separated from liquid decomposition product by adding calcium compound for obtaining insoluble settled-out calcium phosphate by means of phosphate ions, separation of neutralized aqueous phase into aqueous phase containing calcium and chloride ions in form of solution and settled solid phase on base of water-insoluble calcium phosphate and dissolving of at least part of separated settled solid phase in second aqueous hydrochloric acid solution containing hydrochloric acid in the amount exceeding its content in first hydrochloric acid solution, thus forming aqueous solution containing phosphate, chloride and calcium ions extracted by organic extracting agent at extraction in "liquid-liquid" system. Proposed method makes it possible to avoid fine grinding or roasting of ore.

EFFECT: enhanced efficiency of extraction for production of pure concentrated phosphoric acid solution with no contamination of surrounding medium.

24 cl, 2 dwg, 1 tbl, 4 ex

FIELD: paint and varnish industry.

SUBSTANCE: anticorrosive pigment comprises , in mass per cents, 3.0-4.7 of calcium chromate and waterless dicalciumphosphate as the balance.

EFFECT: improved anticorrosion capabilities.

1 tbl

FIELD: chemistry.

SUBSTANCE: method of processing of residual products containing phosphoric acid to calcium phosphates comprises its mixing with calcium-containing compounds, separation of derived slurry with filtration and drying. The limestone is used as calcium-containing compound, initially it is fed for mixing in quantity necessary for monocalcium phosphate, then derived slurry is divided to two flows in ratio 1:(1.5-4), the major flow is mixed with lime taken in quantity necessary for dicalcium phosphate formation, derived slurry is separated with filtration and minor flow of monocalcium phosphate slurry is added to separated dicalcium phosphate before drying and granulating. Preparation of monocalcium phosphate slurry is carried out in two stages, at first stage the phosphoric acid is mixed with limestone up to mixture pH =2.9-3.1, at second stage - up to mixture pH =3.5-3.7, during mixing of monocalcium phosphate slurry with lime pH is maintained in the range 5.4-5.6. Drying and granulating are carried out at the same time in drum granulator-dryer.

EFFECT: method enables to process the residual products to granulated calcium phosphates with usage the lowest-cost raw materials.

3 cl, 1 tbl, 1 ex

FIELD: chemistry.

SUBSTANCE: invention relates to technology of obtaining inorganic materials, namely to methods of obtaining nanosized highly pure hydroxylapatite (HAP) in form of colloid solution or gel, which can be used for production of medico-preventive preparations for stomatology, for application on bone implants. Method of obtaining nanosized colloid hydroxylapatite includes synthesis of hydroxylapatite in saturated solution of calcium hydroxide, decanted after 24-hour settling from sedimented aggregates Ca(OH)2, by adding at rate 1.5-2.2 ml/min per litre of alkali solution 10-20% solution of orthophosphoric acid with constant mixing until pH value of reaction mixture is not lower than 10.5±0.5. Mixture is mixed during 20-30 minutes, settled during 1-2 hours and decanted until liquid phase stops forming on the surface. Obtain product represents colloid solution of highly pure hydroxylapatite with concentration 1.5-2%. Increase of hydroxylapatite concentration within the range from 2 to 30% is carried out by evaporation at temperature not higher than 60°C, and for obtaining nanosized hydroxylapatite with concentration 40±2% initial colloid solution is subjected to complete freezing with further unfreezing at temperature not more than 60°C and liquid phase decanting.

EFFECT: obtaining stable product with set in advance concentration, possessing higher penetrating ability and biochemical activity.

3 cl, 4 ex

FIELD: chemistry.

SUBSTANCE: nano-sized highly-pure hydroxylapatite (HAP) is obtained in form of alcohol colloid solution (gel), which can be used for production of medicinal preventive preparations in stomatology, for applying bioactive coating on bone implants. Method includes hydroxylapatite synthesis by adding solution of orthophosphoric acid to calcium hydroxide solution and exposure to ultrasound impact, and ethyl or isopropyl alcohol is added to colloid of highly-pure nano-sized hydroxylapatite with concentration from 5% to 40±2% in order to obtain concentration of hydrooxylapatite in alcohol from 0.2 to 20%. After that alcohol mixture is processed with ultrasound with frequency 10-50 kHz during 1-2 hours.

EFFECT: alcohol colloid of nano-sized hydroxylapatite with high stability.

2 cl, 3 ex

FIELD: chemistry.

SUBSTANCE: method of phosphate ore processing includes one-step counterflow process of phosphate ore decomposition, characterised by P2O5 content exceeding 20% in weight, by processing it with water solution of hydrochloric acid, which has HCl concentration lower than 10% in weight, with formation of processing solution, consisting of water phase, in which calcium phosphate is in dissolved state, and of solid phase, which contains admixtures; preliminary neutralisation of processing solution, containing calcium phosphate in solution, to first pH value, which is lower than pH value, at which essential part of said dissolved calcium phosphate precipitates in form of calcium monohydrophosphate (DCP), with precipitation of admixtures; first separation of insoluble solid phase and water phase of processing solution; repeated neutralisation of water phase obtained during first separation to second pH value, exceeding said first pH value, with DCP precipitation; and second separation of repeatedly neutralised water medium, which represents water solution of calcium chloride and precipitated DCP.

EFFECT: method allows optimising ratio between dissolved P2O5 output and purity degree of final product and ensure economically profitable process, which can be realised on simple equipment.

14 cl, 3 dwg, 2 tbl, 1 ex

FIELD: medicine, pharmaceutics.

SUBSTANCE: it is described a nanopatterned calcium phosphate material on the basis of threecalciumphosphate-hydroxyapatite system for reconstruction of osteal defects. The invention concerns to the calcium phosphate ceramic materials intended for manufacturing of osteal implants and-or replacement of defects at various osteal pathologies. The material on the chemical compound is close to a natural osteal tissue (the structure corresponds to the threecalciumphosphate-hydroxyapatite system). The unique ultradisperse structure of a material is formed at the expense of use of initial calcium phosphate nanopatterned powders and the additive.

EFFECT: reception of a ceramic material with uniform structure with the average size of particles less than 100 nanometres.

1 tbl, 3 ex

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