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Sulfuric acid adding method for reducing degree of supersaturation of calcium sulfate in wet method phosphoric acid extraction tank

A calcium sulfate, phosphoric acid technology, applied in chemical instruments and methods, calcium/strontium/barium sulfate, phosphorus compounds, etc., to achieve the effect of improving yield, good social and economic benefits, and reducing washing losses

Active Publication Date: 2013-12-25
WENGFU (GRP) CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At present, the phosphorus yield of the wet dihydrate phosphoric acid production process is about 95%, and there is no better way to increase the phosphorus yield, but people are still looking for a technology to reduce phosphorus loss in the wet dihydrate phosphoric acid production process according to local conditions.

Method used

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  • Sulfuric acid adding method for reducing degree of supersaturation of calcium sulfate in wet method phosphoric acid extraction tank

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0021] Example 1: Mix the sulfuric acid with a mass percentage concentration of 98% and the returned phosphoric acid with a mass percentage concentration of 18% at the top of the premixing tank through the mixing tee, enter the premixing tank, and pre-react with the phosphoric acid slurry returned by the flash cooler , enter the reaction tank and then pre-react with the phosphoric acid slurry returned by the flash cooler for the second reaction, and then react with the phosphate rock entering the reaction tank. After being cooled by the flash cooler, part of it enters the phosphoric acid filter for filtration. The total phosphorus in the filtered phosphogypsum is 0.6% lower than the original one.

Embodiment 2

[0022] Embodiment 2: After the mass percent concentration is 98% and the mass percent concentration is 21% returning material phosphoric acid, enter the premix tank after mixing through the mixing tee at the top of the premix tank, and the slurry entering the premix tank is flash cooling The total amount of slurry coming out of the device is 40% (volume ratio), and the temperature of the premixing tank is controlled at 76-78°C. After pre-reacting with the phosphoric acid slurry returned from the flash cooler, it enters the reaction tank and then pre-reacts with the phosphoric acid slurry returned from the flash cooler for the second reaction. The slurry entering the reaction tank is the material from the flash cooler The total amount of slurry is 60% (volume ratio), and the temperature of the reaction tank is controlled at 76-78°C. Then react with the phosphate rock entering the reaction tank, and the temperature of the reaction tank is controlled at 76-78° C. after adding the...

Embodiment 3

[0023] Example 3: Sulfuric acid with a mass percentage concentration of 98% and a percentage concentration of 75% enters the premixing tank at a ratio of 4:1, and the returned phosphoric acid with a mass percentage concentration of 21% is mixed on the top of the premixing tank through a mixing tee before entering the premixing tank After pre-reacting with the phosphoric acid slurry returned from the flash cooler, it enters the reaction tank and then pre-reacts with the phosphoric acid slurry returned from the flash cooler for the second reaction, and then reacts with the phosphate rock entering the reaction tank. After being cooled by the flash cooler, part of it enters the phosphoric acid filter for filtration, and the total phosphorus in the filtered phosphogypsum is reduced by 0.5% compared with the original.

[0024] By adopting the methods of the above three embodiments, the total phosphorus content of phosphogypsum decreased by 0.5% on average, and the phosphorus yield ...

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Abstract

The invention discloses a sulfuric acid adding method for reducing the degree of supersaturation of calcium sulfate in a wet method phosphoric acid reaction tank, relating to calcium sulfate. The method comprises the following steps: additionally arranging a premixing tank, converging sulfuric acid and returning phosphoric acid, adding the acid mixture into the premixing tank, and removing sulfuric acid dilution heat at the same time; cooling the sulfuric acid in the premixing tank and a flash cooler, extracting a returned slurry, and returning the slurry after reaction to the reaction tank to react with an ore slurry so as to produce a mixture of calcium sulfate and calcium phosphate; cooling the mixture of calcium sulfate and calcium phosphate in the flash cooler, and filtering the cooled slurry in a phosphoric acid filter. By adopting the sulfuric acid adding method disclosed by the invention, the total phosphorus content of phosphogypsum is averagely reduced by 0.5%, so that the phosphorus yield of wet-method dihydrate method phosphoric acid is increased to 96%, and the economic benefit brought directly is 60 million RMB per year.

Description

technical field [0001] The present invention relates to phosphoric acid, also relates to calcium sulfate, further specifically, relates to a kind of method of producing calcium sulfate from the production process of wet-process phosphoric acid. Background technique [0002] As we all know, a large amount of phosphogypsum (calcium sulfate) will be produced in the production process of wet-process phosphoric acid. In the traditional production process of wet-process dihydrate phosphoric acid, sulfuric acid is directly added to the reaction tank, so that the dilution heat of sulfuric acid will cause the local temperature of the reaction tank to be too high. , the acid ore is not mixed uniformly, and there will be local supersaturation in the reaction tank, and a large amount of fine and difficult-to-filter CaSO will be produced. 4 .2H 2 O crystals. During the production of wet-process phosphoric acid, CaSO, which is difficult to filter, is generated 4 .2H 2 O crystals serio...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B25/225C01F11/46
Inventor 姚石林朱寿连赵建勇饶轶晟刘海
Owner WENGFU (GRP) CO LTD