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Method for preparing calcium sulfate from ardealite

A technology of phosphogypsum and calcium sulfate, applied in the field of solid waste resource utilization, can solve the problem that phosphogypsum cannot be effectively recycled and other problems

Active Publication Date: 2017-05-24
WUHAN INSTITUTE OF TECHNOLOGY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0003] For the above-mentioned problems in the prior art, the main purpose of the present invention is to provide a kind of method for preparing calcium sulfate by phosphogypsum, after described method handles phosphogypsum, obtained the higher calcium sulfate product of purity and added value, solved The practical problem that phosphogypsum cannot be effectively utilized as a resource

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  • Method for preparing calcium sulfate from ardealite
  • Method for preparing calcium sulfate from ardealite
  • Method for preparing calcium sulfate from ardealite

Examples

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Embodiment 1

[0038] The raw material of this embodiment is phosphogypsum provided by Hubei Xingfa Chemical Group Co., Ltd. Its main components are: CaO 28.98%, P 2 o 5 1.09%, SiO 2 6.06%, MgO 0.18%, Al 2 o 3 0.42%, SO 3 42.32%, CaSO 4 70.36%, crystal water 16.01%. X-ray diffraction analysis shows that the main component of phosphogypsum is CaSO 4 , followed by SiO 2 , and a small amount of colloidal phosphate and aluminosilicate.

[0039] The present embodiment prepares the circulation process of high-purity calcium sulfate by phosphogypsum, is characterized in that comprising the steps:

[0040] (1) Decompose phosphogypsum with NaOH solution: slowly add NaOH solution with a concentration of 2.40mol / L to the reactor containing phosphogypsum raw materials according to the dosage of 11.4mol NaOH / 1kg phosphogypsum, and stir while adding , reacted at room temperature for 10 min. Then the slurry is filtered, and the filter residue is countercurrently washed twice to obtain Na with...

Embodiment 2

[0053] The raw material of this embodiment is phosphogypsum provided by Hubei Xingfa Chemical Group Co., Ltd. Its main components are: CaO 28.98%, P 2 o 5 1.09%, SiO 2 6.06%, MgO 0.18%, Al 2 o 3 0.42%, SO 3 42.32%, CaSO 4 70.36%, crystal water 16.01%. X-ray diffraction analysis shows that the main component of phosphogypsum is CaSO 4 , followed by SiO 2 , and a small amount of colloidal phosphate and aluminosilicate.

[0054] The present embodiment prepares the circulation process of high-purity calcium sulfate by phosphogypsum, is characterized in that comprising the steps:

[0055] (1) Decompose phosphogypsum with KOH solution: slowly add KOH solution with a concentration of 1.80mol / L to the reactor containing phosphogypsum raw material according to the amount of 10mol NaOH / 1kg phosphogypsum, and stir while adding, React at room temperature for 20 min. Then the slurry is filtered, and the filter residue is countercurrently washed twice to obtain a K concentrati...

Embodiment 3

[0066] The raw material of this embodiment is phosphogypsum provided by Hubei Xingfa Chemical Group Co., Ltd. Its main components are: CaO 28.98%, P 2 o 5 1.09%, SiO 2 6.06%, MgO 0.18%, Al 2 o 3 0.42%, SO 3 42.32%, CaSO 4 70.36%, crystal water 16.01%. X-ray diffraction analysis shows that the main component of phosphogypsum is CaSO 4 , followed by SiO 2 , and a small amount of colloidal phosphate and aluminosilicate.

[0067] The present embodiment prepares the circulation process of high-purity calcium sulfate by phosphogypsum, is characterized in that comprising the steps:

[0068] (1) Decompose phosphogypsum with KOH solution: slowly add the NaOH solution with a concentration of 2.60mol / L to the reactor containing the phosphogypsum raw material according to the amount of 12mol KOH / 1kg phosphogypsum, and stir while adding, React at room temperature for 8 minutes. Then the slurry is filtered, and the filter residue is countercurrently washed twice to obtain a K ...

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Abstract

The invention provides a method for preparing calcium sulfate from ardealite. The method comprises the following steps: (1) adding a sodium hydroxide or potassium hydroxide solution into ardealite and stirring; and after room-temperature reaction, performing solid-liquid separation to obtain filter residue and a sulfate solution; and washing the filter residue to obtain calcium slag; (2) treating the sulfate solution obtained in the step (1) to obtain a sodium hydroxide or potassium hydroxide solution and a sulfuric acid solution, wherein the treatment method is electrodialysis or ion exchange; (3) adding a first acid solution into the calcium slag obtained in the step (1), and dissolving the calcium slag to obtain a solution containing calcium ions, wherein the first acid solution is hydrochloric acid or acetic acid; and (4) mixing the sulfuric acid solution obtained in the step (2) with the solution containing calcium ions obtained in the step (3) for exchange reaction to obtain a calcium sulfate precipitate. According to the method, a main product, namely calcium sulfate with relatively high purity and additional value, is obtained by a chemical reagent cycling treatment method, and high-efficiency comprehensive utilization of ardealite is realized.

Description

technical field [0001] The invention belongs to the field of resource utilization of solid waste, in particular to a method for preparing calcium sulfate from phosphogypsum. Background technique [0002] Phosphogypsum is a by-product in the production process of phosphoric acid produced by the wet method of phosphate rock, and about 4 to 5 tons of phosphogypsum will be produced for every ton of phosphoric acid produced. According to statistics from the China Phosphate Fertilizer Industry Association, the cumulative production of phosphogypsum in China has exceeded 300 million tons, and the stockpiles have exceeded 250 million tons. With the depletion of high-grade phosphate rock resources, more low-grade phosphate rocks are developed and utilized, and the production of phosphogypsum continues to increase. The main component of phosphogypsum is CaSO 4 , and its content (mass fraction on dry basis) is about 86%. As a kind of chemical gypsum, phosphogypsum is different from ...

Claims

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Application Information

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IPC IPC(8): C01F11/46C04B11/26
CPCC01F11/46C01P2006/80C04B11/26
Inventor 张泽强黄朝德孙桦林
Owner WUHAN INSTITUTE OF TECHNOLOGY