Process for producing feed grade calcium dihydrogen phosphate by phosphoric acid recycling method

Abstract

The invention discloses a process of producing feed-grade calcium dihydrogen phosphate through a phosphoric acid circulation impurity removal method, wherein the method comprises following steps: (a) decomposing acid mine; (b) maintaining the temperature and performing sedimentation to obtain a slurry material; (c) feeding the slurry material to a crystallization trough, cooling the slurry material to 30-60 DEG C and performing solid-liquid separation to obtain a filtrate and a filter residue; (d) adding water to the filter residue for making material slurry of which the specific gravity is 1.30-1.60; (e) maintaining the temperature and performing sedimentation to obtain a material slurry; (f) feeding the material slurry in the step (e) to a dryer with high-temperature gas flow to dry the material slurry, and adding an alkaline substance to a dried product to obtain the feed-grade calcium dihydrogen phosphate product; and (g) mixing a filtrate in the step (c) with phosphoric acid by wet process, and removing impurities to obtain an acid liquid used for decomposing the acid mine in the step (a). The process is good in adaptability of phosphorus ore, can ensure the product in the step (f) and heavy metals to meet a standard completely, can reduce discharge load of phosphogypsum and is good in application prospect.

Description

technical field

[0001] The invention belongs to the field of phosphate preparation, and in particular relates to a process for producing feed-grade calcium dihydrogen phosphate by a phosphoric acid circulation and impurity removal method. Background technique

[0002] The world's demand for calcium phosphate began in 1940, when meat and bone meal and low-fluorine phosphate rock were initially used. At present, there are mainly three kinds of feed calcium phosphate products: calcium hydrogen phosphate (DCP); calcium dihydrogen phosphate (MCP); defluorinated calcium phosphate (DFP). There is also a large amount of intermediate components of calcium hydrogen phosphate and calcium dihydrogen phosphate, which can be produced by blending calcium hydrogen phosphate and calcium dihydrogen phosphate, or reacting according to the composition ratio during production, that is (MDCP).

[0003] According to the survey, the consumption of phosphorus in the world is roughly in the form of ...

Images