Method for directly carbonizing calcinated mid and low grade phosphate ore ammonium salt lixivium to prepare calcium magnesium carbonate

Abstract

The invention relates to the technical field of inorganic chemical engineering, in particular to a method for directly carbonizing calcinated mid and low grade phosphate ore ammonium salt lixivium toprepare calcium magnesium carbonate. The method utilizes CO2 gas obtained through calcination of phosphate ores, NH3 gas produced in the extracting process of a phosphate ore pyrolysis product to jointly react with the calcinated mid and low grade phosphate ore ammonium salt lixivium, calcium and magnesium in the calcinated mid and low grade phosphate ore ammonium salt lixivium can form calcium magnesium carbonate sediment. The method only uses ammonium nitrate or ammonium chloride solutions to achieve circulation, no loss of ammonium nitrate is caused, and meanwhile, the situation that moisture is newly introduced into a circulation system is avoided; granularity control in the synthesis process of calcium magnesium carbonate is facilitated, and the production capability of filter pressing and washing is improved; the NH3 gas used in the method comes from the reaction of the pyrolysis product and the ammonium nitrate or ammonium chloride solution, CO2 comes from calcinations of the phosphate ores, and the pyrolysis product is obtained, the waste gas needing to be emitted in the original production process is recycled, not only is emission of the waste gas reduced, but also the cost of the raw materials is reduced.

Description

technical field [0001] The invention relates to the technical field of inorganic chemical industry, in particular to a method for preparing calcium and magnesium carbonate by direct carbonization of leaching liquid of ammonium salt of low-grade phosphate rock from calcining. Background technique [0002] Phosphate rock resources are important strategic resources of the country and the material basis of the phosphorus chemical industry. They are non-renewable. my country is rich in phosphor rock resources, but more than 80% of them are medium and low-grade phosphate rocks that are difficult to use directly. [0003] With the massive development and utilization of phosphate rock resources, the raw materials for phosphorus chemical production will have to rely on low- and medium-grade phosphate rock. The key to the utilization technology of low- and medium-grade phosphate rock lies in the enrichment of phosphorus and the removal of impurity magnesium. The low utilization rate o...

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Problems solved by technology

[0004] At present, in the existing technology, the method of leaching calcium and magnesium in ammonium salt solution (ammonium nitrate, ammonium chloride, ammonium sulfate, etc.) 2 o 5 The mass fraction can reach more than 35-38%, MgO≤1.5%). Usually, ammonium carbonate solution is added to the leaching solution to precipitate calcium and magnesium and regenerate the ammonium salt solution. However, since the ammonium carbonate solution is usually dilute Ammonia water is produced by absorbing carbon dioxide. The ammonium carbonate concentration is low and a large amount of water is brought in to cause precipitation of calcium and magnesium. The regenerated ammonium salt solution has a high water content and a low concentration, making it difficult to recycle.

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