Method for producing calcium orthophosphate and high-purity gypsum by using hydrochloric acid and phosphate rock

Abstract

The invention belongs to the technical field of feeds and specifically relates to a method for producing calcium orthophosphate and high-purity gypsum by using hydrochloric acid and phosphate rock. The invention provides the method for producing calcium orthophosphate and high-purity gypsum by using hydrochloric acid and phosphate rock, comprising the following steps: incompletely decomposing phosphate rock with hydrochloric acid, and filtering to obtain a solid 1 and a liquid 1; A. treating the solid 1: carrying out a reaction between the solid 1 and hydrochloric acid, filtering and separating to obtain filter residue and a filtrate 2; adding sulfuric acid into the filtrate 2, filtering to obtain a filtrate 3, heating the filtrate 3 for dechlorination, defluorination and dehydration to obtain calcium dihydrogen phosphate; B. treating the liquid 1: (1) removing fluorine in the liquid 1; (2) adding calcium to prepare calcium hydrogen phosphate; (3) removing magnesium; and (4) adding sulfuric acid to prepare high-purity gypsum. The method has advantages of simple step and low cost; and the prepared calcium orthophosphate completely meets the national standard and the gypsum obtainedhas excellent quality.

Description

technical field [0001] The invention belongs to the technical field of feed and fertilizer, and in particular relates to a method for producing calcium phosphate salt and high-purity gypsum by using hydrochloric acid and phosphate rock. Background technique [0002] Calcium phosphate can be used as fertilizer grade calcium phosphate, widely used in agricultural production, mainly used as raw material for compound fertilizer, and can also be directly applied to farmland; calcium phosphate can be used as feed grade calcium phosphate, suitable for Animals such as livestock, poultry, and aquatic products are feed additives used to supplement the calcium and phosphorus nutrition of livestock, poultry, and aquatic animals. [0003] It is generally believed in the industry that P 2 o 5 24%-28% is medium-grade phosphate rock, and 18%-24% is low-grade phosphate rock. China is relatively rich in phosphate rock resources, and the total amount of proven resources is second only to Mo...

AI Technical Summary

Problems solved by technology

At the same time, most of the existing processes for producing calcium phosphate salt first convert the calcium in phosphate rock into phosphogypsum (calcium sulfate with high impurities) and remove it as industrial waste. The storage and digestion of phosphogypsum is a difficult point in this industry. It has affected the sustainable development of this industry, and in the process of subsequent production of calcium phosphate salt, it is necessary to add a large amount of calcium carbonate as a calcium source, resulting in a great waste of resources

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