Production method for extracting phosphorite cogeneration feed grade monocalcium phosphate and industrial grade monoammonium phosphate

Abstract

The invention discloses a method for extracting phosphorite cogeneration feed grade monocalcium phosphate and industrial grade monoammonium phosphate by phosphoric acid with a wet method. The method comprises the steps that a, preparation of monocalcium phosphate slurry; b. preparation of a monocalcium phosphate semi-finished product; c, preparation of industrial grade monoammonium phosphate; d, preparation of feed grade monocalcium phosphate. According to the method, phosphorite cogeneration feed grade monocalcium phosphate and industrial grade monoammonium phosphate are extracted by by phosphoric acid with the wet method, so that a calcium source in phosphorite is efficiently used, consumption of sulfuric acid in the calcium source of the phosphorite and discharge of ardealite are reduced, consumption of limestone is reduced, and the product quality of feed grade monocalcium phosphate is improved. Accordingly, the production cost of unit product can be reduced, the product quality is improved, the ecological environment is protected, and the method has excellent economic and environmental benefits.

Description

technical field [0001] The invention belongs to the technical field of chemical production, and in particular relates to a method for wet-process phosphoric acid extraction of phosphate rock to co-produce feed-grade calcium dihydrogen phosphate and industrial-grade ammonium dihydrogen phosphate. Background technique [0002] Feed-grade calcium phosphate salt is the main phosphorus and calcium supplement for animals, which has the characteristics of high digestion and absorption rate and high biological potency. Industrial monoammonium phosphate has good thermal stability and water solubility, and is widely used as ABC dry powder fire extinguishing agent, flame retardant, agricultural drip irrigation fertilizer, pharmaceutical and ruminant feed additive. [0003] At present, there are two main production methods for feed grade calcium phosphate salt: hot method phosphoric acid method and wet method phosphoric acid method. [0004] The thermal phosphoric acid method uses ther...

AI Technical Summary

Problems solved by technology

The weak point of this process production method is: (1) the acid slag that (1) wet-process phosphoric acid purification slag and primary neutralization produce all enters phosphate fertilizer system, makes P 2 o 5 The yield decreases, and the unit product P 2 o 5 The overall value is reduced; (2) The calcium in the feed grade calcium hydrogen phosphate product of this process is all derived from limestone, while all the calcium in the phosphate rock is converted into phosphogypsum and discharged, which is not fully utilized in the product and consumes a large amount of sulfuric acid Used to precipitate calcium in phosphate rock; (3) Due to the many types of impurities in phosphogypsum, the high content, and the large output, the utilization rate is low and the value is low. The current stockpiling treatment has a greater impact on the ecological environment

The deficiencies of this process technology are: (1) the P in the industrial grade ammonium dihydrogen phosphate and feed grade calcium phosphate produced by this process 2 o 5 All come from raw phosphoric acid. During the production of raw phosphoric acid, all the calcium in phosphate rock is converted into phosphogypsum, and phosphogypsum has many types of impurities, high impurity content, low utilization rate, and low value. (2) In the production process, a large amount of sulfuric acid is consumed for the precipitation and separation of calcium in phosphate rock, and the recovery rate of sulfur resources is low, and sulfuric acid is one of the main costs in the production process of wet-process phosphoric acid; (3) the Process defluorinated phosphoric acid contains about 2-3% SO 3 , without desulfurization treatment, so SO 4 2- Will enter among the product with the form of calcium sulfate, thereby reduced the purity of final product, has influenced the quality of product; (4) the calcium phosphate salt product that this technique makes is based on calcium hydrogen phosphate, and total P 2 o 5 , water soluble P 2 o 5 Low, did not meet the quality requirements of feed grade calcium dihydrogen phosphate

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