Method for producing feed grade dicalcium phosphate

Abstract

The process of producing feed grade calcium phosphate features that the calcium phosphate producing process includes the first liquid phase neutralizing reaction between dilute phosphoric acid and calcium containing compound in the reactor to produce calcium dihydrogen phosphate slurry, the subsequent adding calcium containing compound for the second liquid phase neutralizing reaction to produce mixture slurry of calcium hydrogen phosphate and calcium dihydrogen phosphate, and the spray drying of the slurry to obtain the calcium phosphate product. The production process has no produced white fertilizer and waste water, high phosphorus utilization rate, low production cost, less environmental pollution and well preservation of crystalline water resulting in high biological potency.

Description

technical field [0001] The invention relates to a method for producing monocalcium phosphate, in particular to a two-step liquid-phase neutralization reaction production of dilute phosphoric acid and calcium-containing compounds (calcium carbonate, calcium oxide, calcium hydroxide and defluorinated tricalcium phosphate). The monocalcium phosphate method. Background technique [0002] Feed grade monocalcium phosphate is between feed grade calcium dihydrogen phosphate and feed grade calcium hydrogen phosphate in performance, and its basic composition is a mineral feed additive of calcium hydrogen phosphate and calcium dihydrogen phosphate. It contains both water-soluble phosphorus and citrate-soluble phosphorus, so it is not only suitable for livestock and poultry feed, but also as a mineral feed additive for aquatic feed, especially for the digestion and utilization of phosphorus in livestock and poultry feed compared with calcium hydrogen phosphate The rate is 7%-14% higher...

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Problems solved by technology

[0007] The first method uses phosphoric acid to react with the semi-finished product of calcium hydrogen phosphate. The first step is to produce the semi-finished product of calcium hydrogen phosphate by precipitation method to make the production process longer. When preparing calcium hydrogen phosphate by precipitation method, white phosphorus fertilizer and mother liquor precipitation and Wastewater, the production cost of this process is high, the utilization rate of phosphorus is low, and the environmental impact is large

[0008] Another method uses concentrated and purified phosphoric acid to directly react with calcium carbonate. Although white phosphorus fertilizer and mother liquor precipitation are no longer produced, and the utilization rate of phosphorus is improved, due to the use of phosphoric acid concentration and defluorination technology, the phosphoric acid concentration device has a large investment and equipment maintenance costs are high; At the same time, due to the solid-phase conversion reaction between concentrated phosphoric acid and calcium carbonate, the aging time is long, the material reaction is not complete, and the product purity is not high.

The most important thing is: due to the lack of free water in the reaction system, the crystallization water of calcium hydrogen phosphate and calcium dihydrogen phosphate generated is incomplete.

According to the research of Sichuan Agricultural University Caohui (2003) and RUCKER (1968), it is found that the dissolution rate of phosphate containing crystal water in acidic environment is faster than that of phosphate without crystal water, and the phosphate containing crystal water dissolves in the small intestine Under the action of gastric acid, it can be quickly dissolved and absorbed by animals. Therefore, the absorption and utilization rate of phosphate containing crystal water by animals is higher than that of phosphate without crystal water. The biological potency is lower than that of monocalcium phosphate products containing crystal water completely

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