Method for highly water-soluble nitrophosphate fertilizer production through decomposition of rare earth-containing phosphate rock by nitric acid and for rare earth recovery

Abstract

The invention discloses a method for highly water-soluble nitrophosphate fertilizer production through decomposition of rare earth-containing phosphate rock by nitric acid and for rare earth recovery. Through the processes of rare earth-containing phosphate rock decomposition by nitric acid, defluorination, freezing separation of calcium nitrate, deep decalcification of ammonium sulfate, neutralization with ammonia water and deposition of rare earth and other impurities, and finally evaporation concentration and crystallization, the nitrophosphate fertilizer can be produced. The method comprises: the first step, acidolysis; the second step, defluorination; the third step, freezing crystallization of calcium nitrate; the forth step, double decomposition of ammonium sulfate for decalcification; the fifth step, neutralization and deposition of rare earth; the sixth step, evaporation concentration and crystallization; the seventh step, phosphogypsum conversion; and the eighth step, re-concentration rare earth in neutralization slag. The method of the invention can produce a highly water-soluble nitrophosphate fertilizer with water solubility of more than or equal to 99.9%, wherein, the nitrate nitrogen is easier for crops to adsorb. With a high utilization rate, the fertilizer in the invention can increase the yield of crops by 8%-25% and can improve product quality simultaneously. With less discharge of waste, the method provided in the invention recovers rare earth in phosphate rock economically and effectively, and maximizes resource utilization, thus breaking a new path for comprehensive utilization of rare earth-containing phosphate rock.

Description

technical field [0001] The invention relates to phosphate fertilizer produced by leaching phosphate rock with nitric acid, and also relates to the recovery of rare earth metals, in particular to a method for producing highly water-soluble nitrophosphate fertilizer with nitric acid and simultaneously recovering rare earth. Background technique [0002] As we all know, it is a group of new functional materials with multiple properties such as electricity, magnetism, light, and biology, and it is also a key material for many major weapon systems. In nature, rare earth resources are very precious, and some of them coexist with apatite and phosphorite ore. Therefore, when using phosphate rock to produce phosphate fertilizer, the recovery of rare earth resources must be considered. Decomposing phosphate rock with sulfuric acid and neutralizing it with ammonia to produce phosphate fertilizer has been a widely used technology, but it is still a big problem to economically and effect...

AI Technical Summary

Problems solved by technology

There are some technical solutions in the Chinese patent database, such as No. 00112697.0 "Nitrate Phosphate Fertilizer Production Method for Direct Freezing and Crystallization of Low Back Pressure Supersonic Nozzle", No. 200910009223.3 "A Process for Producing High Concentration Nitrophosphate Fertilizer", etc., but to So far, there is no nitric acid to decompose rare earth-containing phosphate rock, freeze and separate calcium nitrate, neutralize and precipitate rare earth and iron, magnesium, aluminum and other insoluble impurities and separate them, and then evaporate, concentrate and crystallize to produce highly water-soluble nitrophosphate fertilizer, and at the same time recover from neutralization slag Rare earth process reports, and no related patent applications

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