Method of combined production of multiple phosphates and phosphate fertilizer from low grade phosphate ore

Abstract

The invention relates to a method of combined production of multiple phosphates and a phosphate fertilizer from low grade phosphate ore. The method comprises the following steps: decomposing low grade phosphate ore powder by using hydrochloric acid to obtain an extract liquid containing calcium dihydrogen phosphate and calcium chloride; neutralizing the extract liquid by using ammonia by two segments to respectively obtain fertilizer-grade potassium dihydrogen phosphate and feed-grade calcium hydrogen phosphate, carrying out reaction on the neutralization liquid from the two segments and potassium sulfate and / or potassium bisulfate, and concentrating a filtrate to prepare a great amount of element water soluble fertilizers, or adding low molecular weight ammonium polyphosphate into the filtrate to prepare a suspended water soluble fertilizer. According to the method disclosed by the invention, by utilizing the characteristic of high decomposition rate by extracting phosphate ores by hydrochloric acid, with the combination of the technical characteristics of different phosphates and phosphate fertilizer products and different product standard requirements, the process technical requirements among the products are effectively jointed with one another, and the products including the feed-grade calcium hydrogen phosphate, the fertilizer-grade potassium dihydrogen phosphate, the water soluble fertilizer and gypsum whiskers are in combined production, so that the production process technology of each product is simple and feasible, phosphorus, calcium, magnesium and fluorine in the phosphate ores are fully utilized and the production cost of each product is also lowered.

Description

technical field [0001] The invention relates to a method for decomposing low-grade phosphate rocks with hydrochloric acid to prepare various phosphates and phosphate fertilizers, specifically a method for co-producing feed-grade calcium hydrogen phosphate, fertilizer-grade potassium dihydrogen phosphate and water-soluble fertilizers with low-grade phosphate rocks. method of fertilizer. Background technique [0002] my country's low-grade phosphate rock resources are very rich, but how to use them has always puzzled people in the industry. Due to low-grade phosphate rock P 2 o 5 Low content, high impurity content, not only low decomposition rate (if hydrochloric acid is not used), but also high acid consumption and many residues. If not comprehensively utilized, the method of combining fertilizer and salt will be used to produce a variety of products with large market capacity and high added value. will have no economic value. For example, the utilization methods disclose...

AI Technical Summary

Problems solved by technology

Due to low-grade phosphate rock P 2 o 5 Low content, high impurity content, not only low decomposition rate (if hydrochloric acid is not used), but also high acid consumption and many residues. If not comprehensively utilized, the method of combining fertilizer and salt will be used to produce a variety of products with large market capacity and high added value. will have no economic value

For example, the utilization methods disclosed in patent documents CN102134063, CN102923681, and CN101293640 are not only complicated in technology, but also only extract the phosphorus therein, and do not utilize the calcium and magnesium therein.

Although the patent document CN101380062 prepares the calcium into calcium chloride, it is not feasible in terms of economy and market. In addition, magnesium is not utilized, and magnesium is still circulating and accumulating in the system. In addition, its potassium and sodium salts The limited defluorination technology, using this method, the general phosphate rock cannot produce feed grade calcium hydrogen phosphate that meets the standard

Patent document CN101219781 uses hydrochloric acid drip irrigation and leaching method not only does not consider environmental pollution, but its production process is lengthy and complicated, and the utilization cost is high, so it is difficult to realize industrial production

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