The method of obtaining calcium orthophosphate one-deputizing

 

(57) Abstract:

The invention relates to the production of calcium phosphates, in particular calcium orthophosphate one-deputizing used in the food industry. The invention consists in the method of producing calcium orthophosphate one-deputizing, which includes evaporation of phosphoric acid to the content of P2O565-67,5%, followed by neutralization with calcium carbonate when the initial molar ratio of CaO/P2O5equal (0,95-1,0):1 and grinding the mass to obtain a particle size of not more than 0.10 mm, the Technical result of the developed method consists in reducing the duration of the process and excluding energy-intensive technological operations by ensuring conditions that reduce the viscosity and humidity the mass of calcium orthophosphate one-deputizing, as well as in increasing output and improving the quality of end product. table 1.

The invention relates to the production of calcium phosphates, in particular calcium orthophosphate one-deputizing used in the food industry as a leavening agent, acidity regulator, flour improver, bread, stabilizer texturebrush substances, otveta of one-deputizing calcium (phosphate), including the neutralization of phosphoric acid with calcium carbonate to free acidity equal 144-264 g/l followed by parcoy and crystallization upon cooling to 25oC and separation of products by centrifugation (ed. St. USSR N 1169941, IPC C 01 B 25/32, publ. 30.07.85, bull. N 28).

The disadvantage of this method is its low efficiency, due to the presence of energy-intensive crystallization and centrifugation, also on the efficiency of the process has a negative impact in that it provides chemically pure raw materials. In addition, obtained in a known manner brand monocalcium phosphate has a limited scope due to the presence of free phosphoric acid. A close analogue of the claimed invention is a method of obtaining calcium orthophosphate one-deputizing (phosphate), including the process of evaporation of phosphoric acid, followed by neutralization with calcium carbonate (ed. St. USSR N 193917, IPC C 01 B 25/32, publ. 13.03.67, bull. N 3).

The known method provides for concentrating wet-process phosphoric acid to the content of P2O545-55% in the presence of silica is added in an amount up to is about 57%2O5and up to 0.2% of fluoride.

The disadvantage of this method is its low efficiency, due to the duration and intensity of the process, as well as low quality commodity calcium orthophosphate one-deputizing.

As shown by experiments carried out under conditions known way, the deficiencies noted primarily due to the fact that the thus obtained semi-product is a viscous wet mass containing unreacted products (for example, the free acid), a drying process which is extremely difficult and prolonged (up to 1-2 days). The yield of the finished product is not more than 85%.

The claimed invention is directed to the development of a simple and economical method of obtaining calcium orthophosphate one-deputizing, allowing to obtain high-quality marketable product.

The technical result of the developed method consists in reducing the duration of the process by ensuring conditions that reduce the viscosity and moisture content of the intermediate product, as well as increasing output and improving the quality of commercial calcium orthophosphate one-deputizing.

This technical result costigliola neutralizing calcium carbonate, in which phosphoric acid is evaporated to contents P2O565-67,5%, neutralization is carried out at the initial molar ratio of CaO/P2O5equal (0,95-1,0):1, and the resulting mass is crushed to obtain particles with a size of not more than 0.10 mm

The essence of the proposed method consists in the following.

Research has established that carrying out neutralization previously one stripped off before the content of P2O565-67,5% phosphoric acid calcium carbonate in the claimed ratio of the components, with subsequent grinding of the mass to the particle size of no more than 0.10 mm provides obtaining dietary calcium orthophosphate one-deputizing high quality while significantly reducing the duration and intensity of the process.

Thus, it was determined that the preliminary evaporation of phosphoric acid to the claimed content of P2O5equal 65,0 is 67.5%, can significantly reduce the amount of water produced during the neutralization reaction mass of calcium orthophosphate one-deputizing, as well as to reduce its viscosity. The process with enough concentrated acid (65.0% and above) leads to a significant hydrolytic R is th product. Excessive (more 67,5%) concentration of phosphoric acid leads to the formation of impurities nakilat and lack crystallohydrates water in the finished product.

The claimed range of molar ratios of CaO/P2O5average (0,95-1,0): 1, was determined experimentally on the basis of optimum moisture content in the intermediate (obtained mass of calcium orthophosphate one-deputizing) and the lack of any traces of unreacted reagents.

It turned out that neutralised when the value of the ratio CaO/P2O5exceeding 1.0: 1, observed the formation of impurities of dicalcium phosphate, which leads to decrease in the content of the basic substance in the finished product, while not achieving the claimed ratio also leads to a decrease in the content of the basic substance due to the presence of excess unreacted acid.

Essential as to increase the yield of marketable product and to improve its quality, as it turned out, renders the subsequent grinding of the mass of calcium orthophosphate one-deputizing.

During the experiments it was found that in the case of grinding the aqueous product and its quality improved.

It can be assumed that the above contributes to a more complete passage of the neutralization, namely the grinding of the mass of calcium orthophosphate to the claimed particle size leads to a significant increase of the contact surface phases, resulting enters the reaction of unreacted phosphoric acid, which ultimately provides higher yield and improved quality.

Below is an example of confirming the possibility of implementing the claimed invention to obtain the above-mentioned technical result.

Example

In the reactor with a working mixer serves phosphoric acid with a density of 1.57 g/cm3in the amount of 500 liters, then it is evaporated to a concentration of 66.0% of the P2O5In the reactor add the calcium carbonate in the amount of 283 kg (ratio of CaO/P2O5is to 0.96:1).

The resulting suspension is cooled to a temperature of 20oC. the Resulting orthophosphate calcium crushed to particle size of not more than 0.1 mm, the Yield was 97% from stoichiometry, the content of the basic substance - 98,0%, the content of impurities meets the requirements of the calcium orthophosphate odnosima is.

In this table compares the performance of the proposed method (NN experiments 2, 3, 6, 7, 9 and 10), and experiments, the conditions which go beyond regulated by the formula of the invention (experiments 1, 4, 5, 8 and 11).

As can be seen from the presented data, only the totality of the claimed features enables optimal performance of the process of obtaining calcium orthophosphate one-deputizing. In violation of the proposed ratios of components a decrease in the quality and yield of the finished product (experiments 1, 4, 5, 8 and 11).

Thus, the invention successfully solves the problem of creating a simple and economical method of obtaining calcium orthophosphate one-deputizing in order to reduce energy consumption by eliminating energy-intensive operations of drying and centrifugation, to ensure optimal performance of the process and high quality product.

The method of obtaining calcium orthophosphate one-deputizing, including evaporation of phosphoric acid, followed by neutralization with calcium carbonate, characterized in that the phosphoric acid is evaporated to contents P2O565 is 67.5%, neutralization is carried out at ischaemic size of not more than 0.10 mm

 

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