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Method for decomposing phosphate rock acidolysis liquid by nitric acid to remove calcium byproduct alpha high-strength gypsum

A technology of high-strength gypsum and acid hydrolyzate, applied in chemical instruments and methods, phosphoric acid, phosphorus compounds, etc., can solve the problems of inability to produce fine phosphate and highly water-soluble phosphate fertilizer products, and achieve the effect of reducing production costs

Active Publication Date: 2020-08-14
GUIZHOU UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, its freezing decalcification rate is 70-80%, and the decalcification mother liquor cannot produce fine phosphate and highly water-soluble phosphate fertilizer products.

Method used

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  • Method for decomposing phosphate rock acidolysis liquid by nitric acid to remove calcium byproduct alpha high-strength gypsum
  • Method for decomposing phosphate rock acidolysis liquid by nitric acid to remove calcium byproduct alpha high-strength gypsum

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Experimental program
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Effect test

Embodiment 1

[0048] Embodiment 1, implement raw material: 1, phosphate concentrate powder: P 2 0 5 (31.12%); CaO (46.23%); 2, nitric acid; 3, ammonium sulfate; 4, phosphoric acid; 5, ammonia water.

[0049] A method for decomposing phosphate rock acid hydrolysis solution with nitric acid to remove calcium and by-product alpha high-strength gypsum, specifically comprising the following steps:

[0050] (1) Acid hydrolysis: carry out acid hydrolysis reaction with nitric acid after adding water to phosphate concentrate powder, the mass concentration of nitric acid is 45%, the acid ore ratio of nitric acid and phosphate concentrate is 1.25:1, and the acid excess coefficient of nitric acid is 115%, The temperature of the acidolysis reaction is 65°C, and the reaction time of the acidolysis is 3 hours to obtain a crude acidolysis solution;

[0051] (2) Filtration: the crude acid solution of step (1) is filtered to remove acid insolubles and organic matter, to obtain acid solution;

[0052] (3) ...

Embodiment 1

[0057] Implement 1 result: the decalcification rate of phosphate ore acid hydrolysis solution of the present invention is up to more than 95% (calcification rate=calcium oxide quality in the decalcification acid solution solution / calcium oxide quality in the diluted acid solution before decalcification, decalcification rate=( 0.32 / 7)*100%=95.43%); high-quality gypsum: the content of calcium sulfate in gypsum is 99.5% after testing. The initial setting time is 7min, the final setting time is 14min, the two-hour compressive strength is 6MPa, the absolute dry flexural strength is 11MPa, and the absolute dry compressive strength is 35MPa.

Embodiment 2

[0058] Embodiment 2, implement raw material: 1, phosphorus concentrate powder: P 2 0 5 (31.12%); CaO (46.23%); 2, nitric acid; 3, ammonium sulfate; 4, phosphoric acid; 5, ammonia water.

[0059] A method for decomposing phosphate rock acid hydrolysis solution with nitric acid to remove calcium and by-product alpha high-strength gypsum, specifically comprising the following steps:

[0060] (1) Acid hydrolysis: carry out acid hydrolysis reaction with nitric acid after adding water to phosphorous concentrate powder, the mass concentration of nitric acid is 60%, the acid-mineral ratio of nitric acid and phosphorous concentrate is 1.3:1, and the acid excess coefficient of nitric acid is 120%, The temperature of the acidolysis reaction is 60°C, and the reaction time of the acidolysis is 2 hours to obtain a crude acidolysis solution;

[0061] (2) Filtration: the crude acid solution of step (1) is filtered to remove acid insolubles and organic matter, to obtain acid solution;

[00...

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Abstract

The invention discloses a method for decomposing a phosphate rock acidolysis liquid by nitric acid to remove calcium byproduct alpha high-strength gypsum. The method comprises: decomposing phosphoriteby nitric acid, filtering out acid insoluble substances, partially neutralizing the acidolysis liquid, regulating and controlling the concentration of calcium ions in the acidolysis liquid, adding the acidolysis liquid into a crystallization tank containing a mixed solution of additional phosphoric acid and ammonium sulfate, controlling the reaction temperature to be 50-70 DEG C and the reactiontime to be 0.5-2 hours to firstly generate dihydrate gypsum, then, making the reaction slurry flow into a crystal transformation tank, and raising the temperature to 95 to 110 DEG C for reacting for aperiod of time so that an alpha-type high-strength gypsum product can be produced as a byproduct. According to the invention, the acidolysis liquid can be used for producing products such as fine phosphate, high-water-solubility phosphate fertilizer and the like, meanwhile, calcium resources in the acidolysis liquid are converted into an alpha high-strength gypsum product, solid waste phosphogypsum is changed into product phosphogypsum, environmental risks caused by the fact that a large amount of solid waste phosphogypsum is produced as a byproduct in the ammonium phosphate industry are eliminated, the phosphorus compound fertilizer industry is promoted to adjust the product structure, solid waste emission is reduced, and sustainable development of the phosphorus chemical industry is promoted.

Description

technical field [0001] The invention relates to a method for decalcifying phosphate rock acid hydrolysis solution to produce alpha high-strength gypsum by-product, in particular to a method for decomposing phosphate rock acid hydrolysis solution to decalcify by-product alpha high-strength gypsum. Background technique [0002] The mineral composition of α-type high-strength gypsum is α-type hemihydrate gypsum. The α-type hemihydrate gypsum with different crystal forms has different gel strength, and the strength of the needle-like α-type hemihydrate gypsum is the lowest, even worse than that of the scale-like β-type hemihydrate gypsum. Short columnar α-type hemihydrate gypsum has the characteristics of small water-to-paste ratio, short setting time and high flexural and compressive strength under standard consistency. It is widely used in gypsum ceramic molds, precision casting, building decoration materials and other fields. Therefore, the production of short columnar α-typ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01F11/46C01B25/22
CPCC01F11/46C01B25/2216C01P2006/80C01P2004/01
Inventor 曹建新杨林李玉录
Owner GUIZHOU UNIV
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