Method for producing phosphoric acid by-product low-silicon phosphogypsum from high-silicon phosphate rock

Abstract

The invention discloses a method for producing a byproduct low-silicon ardealite by using high-silicon phosphorite. The method is as follows: high-silicon phosphorite powder enters more than one stage of countercurrent decomposition reaction tank for performing more than one countercurrent decomposition reaction and thickening, wherein the countercurrent decomposition reaction tank is composed of a decomposition reaction tank and a thickening classifier; one part of materials subjected to countercurrent decomposition reaction and thickening enters a sedimentation and crystallization tank and performs sedimentation and crystallization reaction with sulfuric acid to prepare phosphoric acid and low-silicon ardealite, another part of materials enters a solid-liquid separator for performing solid-liquid separation, and another part of materials returns a first-stage decomposition reaction tank and reacts with the high-silicon phosphorite powder. According to the method, the difficulty of too high silicon content in the byproduct ardealite when the phosphoric acid is produced by adopting a wet process is solved, the quality of the byproduct ardealite is improved, the content of the silicon in the ardealite is reduced, the influence factor of developing and applying the ardealite due to silicon content is eliminated, a firm resource foundation is laid for completely utilizing the ardealite, the economic benefit of a producer is increased, and the difficulty of environment protection of piling and treating the ardealite is eliminated.

Description

technical field [0001] The invention relates to a method for producing phosphogypsum by-product of wet-process phosphoric acid, in particular to a method for producing low-silicon phosphogypsum by-product of phosphoric acid from high-silicon phosphate rock. Background technique [0002] In the production of wet-process phosphoric acid, phosphoric acid solution is obtained through metathesis reaction between phosphate rock and sulfuric acid, and the calcium ions and sulfate ions in the phosphate rock crystallize and precipitate gypsum calcium sulfate. Because calcium sulfate comes from phosphorus chemical production, it is customarily called phosphogypsum . Its main production chemical reaction principle is as follows: [0003] Ca 5 F(PO 4 ) 3 +5H 2 SO 4 +10H 2 O→3H 3 PO 4 +5CaSO 4 2H 2 O↓+HF↑ (1) [0004] Some impurities such as iron, aluminum, and magnesium brought from the phosphate rock also participate in the reaction, and most of the generated phosphate rema...

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Problems solved by technology

[0021] In order to overcome the shortcoming that the silicon content in the by-product phosphogypsum produced by wet-process phosphoric acid from high-silicon phosphate rock is too high, it cannot be used as a resource or has a relatively small range of utilization. A method of producing low-silicon phosphogypsum by-product, the method of producing phosphoric acid by-product low-silicon phosphogypsum from high-silicon phosphate rock, using phosphoric acid to decompose phosphate rock, removing silicon compounds in the phosphate rock, and then using sulfuric acid to precipitate phosphoric acid to decompose phosphate rock to produce Calcium ion compound, which reduces the silicon content in phosphogypsum, does not use the high-cost high-silicon phosphate ore beneficiation method before wet-process phosphoric acid production, nor does it use chemical flotation for phosphogypsum after wet-process phosphoric acid production The method of separating and removing silicon greatly simplifies the silicon removal process, achieves the purpose of saving energy, reducing investment, reducing production costs, increasing production capacity, and increasing the economic benefits of producers, eliminating the fact that high-silicon phosphogypsum cannot be used as a resource and is environmentally friendly. problem

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