The role of calcium dihydrogen phosphate
Calcium dihydrogen phosphate is a colorless triclinic flaky, granular or crystalline powder inorganic compound with a strong sour taste, does not absorb moisture when pure, contains trace impurities, and can lose crystal water at 100°C, 200 V When decomposed, soluble in dilute hydrochloric acid, dilute nitric acid and dilute acetic acid, slightly soluble in water, insoluble in ethanol.
Calcium dihydrogen phosphate is widely used as a feed additive for aquaculture animals and livestock and poultry animals. It is used as a leavening agent, dough regulator, buffer, nutritional supplement, emulsifier, stabilizer and other quality improvers. Complexing metal ions, pH value, increasing ionic strength, etc., can improve the adhesion and water holding capacity of food.
my country stipulates that it is used for bread, biscuits, and baking powder, and the maximum dosage is 4g/kg in terms of phosphoric acid; the dosage in solid drinks is 8g/kg. It can also be used as analytical reagent, refractory industry, waste water treatment, plastic fixative, etc. It can be seen that calcium dihydrogen phosphate is widely used in industry and occupies an important position in the national economy.
At present, industrial calcium dihydrogen phosphate is mainly used in feed, food additives, gypsum abrasives, plastic stabilizers and pharmaceutical additives. It is produced by neutralization method and metathesis method; among them, the neutralization method is neutralized by thermal phosphoric acid, food-grade phosphoric acid or wet-process purified phosphoric acid and calcium hydroxide (or limestone), and then washed, centrifugally dehydrated, dried, and pulverized Obtain product, its process production cost is high, energy consumption is high, pollution is big, process route is long, economic benefit is not high, is unfavorable for environmental protection; Mixed solution, then add calcium chloride solution to carry out metathesis reaction, and then neutralize until the pH of the reaction slurry is about 3.0. This method has a long process flow, and the incorporation of chloride ions in the middle makes the product quality unstable.
An optimized production method of calcium dihydrogen phosphate is to directly react urea phosphate and calcium hydroxide to produce calcium dihydrogen phosphate under the condition that the temperature is controlled at 50-70°C and the stirring reaction time is 20-50 minutes; Using high-purity urea phosphate to react with calcium hydroxide to prepare dicalcium phosphate, which breaks through the technical defects of direct production of calcium dihydrogen phosphate from phosphoric acid, shortens the production process of calcium dihydrogen phosphate, and reduces production costs; through the process conditions The accurate grasp and control of the product improves the purity of the calcium dihydrogen phosphate product, and the quality is stable, which fully meets the standards of the feed grade calcium dihydrogen phosphate.