Method for graded production of wet-process phosphoric acid

A technology of wet-process phosphoric acid and phosphoric acid, applied in chemical instruments and methods, phosphorus compounds, inorganic chemistry, etc., can solve problems such as difficult removal, achieve high product quality, round appearance, and improve market competitiveness

Active Publication Date: 2021-03-02
YUNNAN YUNTIANHUA RED PHOSPHORUS CHEM CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007] The purpose of the present invention is to provide a method for the graded production of wet-process phosphoric acid to solve the problem of the difficulty in removing Al quickly and efficiently in the existing wet-process phosphoric acid production. 2 o 3 The problem

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  • Method for graded production of wet-process phosphoric acid

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0052] The wet-process phosphoric acid classification production method of the present invention comprises the following steps:

[0053] A step: the flotation concentrate pulp is secondary classified with a cyclone, dewatering is carried out by classifying the concentrate pulp with low impurities at the bottom to step B, and the top concentrate pulp with high impurities is settled and concentrated by the pulp thickener, and the thickener The bottom pulp enters the reaction tank of the 130,000-ton / year dihydrate phosphoric acid production unit, and the upper clarified water is used as the production water of the grinding unit.

[0054] Step B: the bottom concentrate pulp with low impurities in step A is dehydrated with a pressure filter, and after pressure filtration, a concentrate pulp filter cake is formed, and the water content of the filter cake is controlled at 14-16wt%. The filtrate is used for the production water of the phosphate rock grinding plant.

[0055] Step C: T...

Embodiment 2

[0065] The wet-process phosphoric acid classification production method of the present invention comprises the following steps:

[0066] A step: the flotation concentrate pulp is secondary classified with a cyclone, dewatering is carried out by classifying the concentrate pulp with low impurities at the bottom to step B, and the top concentrate pulp with high impurities is settled and concentrated by the pulp thickener, and the thickener The bottom pulp enters the reaction tank of the 130,000-ton / year dihydrate phosphoric acid production unit, and the upper clarified water is used as the production water of the grinding unit.

[0067]Step B: the bottom concentrate pulp with low impurities in step A is dewatered with a pressure filter, and a concentrate pulp filter cake is formed after the filter press, and the water content of the filter cake is controlled at 13-15wt%. The filtrate is used for the production water of the phosphate rock grinding plant.

[0068] Step C: The con...

Embodiment 3

[0074] The wet-process phosphoric acid classification production method of the present invention comprises the following steps:

[0075] A step: the flotation concentrate pulp is secondary classified with a cyclone, dewatering is carried out by classifying the concentrate pulp with low impurities at the bottom to step B, and the top concentrate pulp with high impurities is settled and concentrated by the pulp thickener, and the thickener The bottom pulp enters the reaction tank of the 130,000-ton / year dihydrate phosphoric acid production unit, and the upper clarified water is used as the production water of the grinding unit.

[0076] Step B: the bottom concentrate pulp with low impurities in step A is dewatered with a pressure filter, and after pressure filtration, a concentrate pulp filter cake is formed, and the water content of the filter cake is controlled at 12 to 14wt%. The filtrate is used for the production water of the phosphate rock grinding plant.

[0077] Step C:...

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Abstract

The invention discloses a method for graded production of wet-process phosphoric acid, belonging to the technical field of production of wet-process phosphoric acid. The method comprises the followingsteps: subjecting phosphate concentrate pulp having undergone flotation to graded dehydration to obtain a concentrate pulp filter cake; extracting concentrated phosphoric acid from the filter cake and industrial sulfuric acid by adopting a hemihydrate-dihydrate recrystallization concentrated acid process; feeding the generated concentrated phosphoric acid into a desulfurization reaction tank fora desulfurization reaction with the concentrate pulp; feeding the desulfurized concentrated phosphoric acid into a thickener for clarification; subjecting clarified clear acid to overflowing into a decolorizing reaction tank; conducting decolorizing by using activated carbon; carrying out filter pressing by using a plate-and-frame filter press to obtain high-quality fertilizer-grade phosphoric acid with a P2O5 content of greater than or equal to 40 wt%, a SO4<2-> content of less than or equal to 0.5 wt%, a solid content of less than or equal to 0.2 wt% and an MER of less than or equal to 0.10;and conveying the other part of the concentrate pulp obtained after grading, slag acid formed after sedimentation of the thickener and filter residues generated by filter pressing after decolorationto a phosphoric acid dihydrate production device. According to the method, a part of sesquioxide is reduced in a grading manner, so the concentrate pulp is subjected to graded utilization under the condition that a P2O5 recovery rate is not reduced; and high-concentration phosphoric acid is prepared by using the filter cake, and the content of impurities in phosphoric acid is further reduced.

Description

technical field [0001] The invention relates to the technical field of wet-process phosphoric acid production, in particular to a method for graded production of wet-process phosphoric acid. Background technique [0002] Wet-process phosphoric acid is an important raw material for the production of phosphate fertilizers and phosphorus-containing feeds. At present, the preparation of wet-process phosphoric acid mainly uses strong inorganic acids (sulfuric acid, nitric acid, hydrochloric acid, etc.) to extract and decompose phosphate rock pulp or phosphate rock powder to produce phosphoric acid. most. Ore powder is gradually replaced by ore pulp due to the harsh operating environment. On the other hand, due to the gradual depletion of phosphate rock resources, the grade of phosphate rock continues to decrease, and the content of iron, magnesium, aluminum and other impurities in the phosphate rock gradually increases, resulting in the need to remove phosphorus. The ore is flot...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B25/222C01B25/234
CPCC01B25/222C01B25/234
Inventor 李飞陈恩国周华波唐应生雷银贵吴兴买张猛李彦春白树彬刘洪刘文凯王思祥
Owner YUNNAN YUNTIANHUA RED PHOSPHORUS CHEM CO LTD
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