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Purification method of gypsum containing raw material

A purification method and raw material technology, applied in chemical instruments and methods, inorganic chemistry, calcium/strontium/barium compounds, etc., can solve problems such as poor economy, high energy consumption, and low gypsum value, and achieve improved purity and high product purity , The effect of thorough separation of impurities

Active Publication Date: 2018-12-07
北京中金瑞丰环保科技有限公司
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  • Abstract
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  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At present, the purification of desulfurized gypsum and phosphogypsum includes two processes: physical purification and chemical purification. The physical purification method uses hydrocyclone sorting or particle classification separation equipment to purify waste gypsum by physical means. The cost is relatively low, but the resulting purified gypsum lower quality
The chemical purification method dissolves the waste gypsum in the extraction solution, and recrystallizes the gypsum by heating, cooling or other methods to obtain gypsum with high purity. However, this method has high energy consumption, poor economic efficiency, and limited industrial application.
Therefore, there is an urgent need for a low-energy, high-efficiency waste gypsum extraction process to solve the problem of waste gypsum accumulation that cannot be treated at present
[0004] At present, waste gypsum (mainly including desulfurization gypsum and phosphogypsum) mainly relies on pickling, gravity and particle size sorting to separate impurities in gypsum. These two methods can separate part of the impurities in waste gypsum, so that the taste of gypsum can reach 90% % above, but can not achieve complete separation
For example, calcium phosphate and calcium fluoride in phosphogypsum, calcium carbonate in desulfurized gypsum, etc., are closely combined with gypsum, and physical methods cannot be completely separated. Only chemical purification methods can be used to purify through dissolution-recrystallization. Although There are some methods to achieve recrystallization and purification of gypsum, but the value of gypsum is low. The current gypsum recrystallization method is too expensive and has no industrial value. Therefore, a low-cost, efficient and environmentally friendly method is needed to separate impurities in waste gypsum , to purify the gypsum

Method used

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  • Purification method of gypsum containing raw material

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0055] 1) Configure 50L containing 1.5mol / L ethylenediamine, 0.5mol / L propylamine, 1.0mol / L histidine, 0.5mol / L ethanol, 0.5mol / L sodium sulfate, 0.8mol / L nickel sulfate, 0.5g / Add 4.3kg of phosphogypsum to an aqueous solution of L sodium lauryl sulfate at 90°C, use sodium hydroxide to maintain the pH value of the solution between 10.0-10.5, react for 3.0 hours, and filter to obtain a calcium-containing solution.

[0056] 2) Add 20% sulfuric acid solution to the calcium-containing solution obtained in step 1), so that the pH value is gradually reduced to below 7.0, during which the reaction temperature is controlled between 90-95° C., and the reaction time is 8 hours. After the reaction is completed, filter and wash , to obtain calcium sulfate and reaction mother liquor.

Embodiment 2

[0058] 1) Prepare 100L of reaction solution containing 1.5mol / L ethylenediaminetetraacetic acid, 0.2mol / L glutamic acid, 0.5mol / L sodium sulfate, 2.0mol / L copper nitrate, and 2.5mol / L sodium nitrate at 60°C Add 2.8 kg of desulfurized gypsum, use ammonia water to maintain the pH value of the solution between 9.0-9.5, react for 5.0 hours, and filter to obtain a calcium-containing solution.

[0059] 2) Transfer the calcium-containing solution obtained in step 1) to another reactor, reduce the pressure to 50kpa, volatilize the ammonia gas in the solution, and gradually reduce the pH value to below 6.0, during which the reaction temperature is controlled between 60-65°C After the reaction, filter and wash to obtain calcium sulfate and reaction mother liquor.

[0060] 3) The reaction mother liquid obtained in step 2) is adjusted to a pH value between 9.0-9.5 with ammonia water, and returned to step 1) as a reaction liquid for recycling.

Embodiment 3

[0062] 1) Configure 500L containing 1.0mol / L nitrilotriacetic acid, 0.1mol / L ethylenediamine diacetic acid, 1.0mol / L ethylenediamine, 0.2mol / L glycerol, 3.0mol / L ammonium sulfate, 0.8mol / L Add 56kg of phosphogypsum to the copper sulfate reaction solution at 80-85°C, use ammonia water to maintain the pH value of the solution between 10.4-11.0, react for 2.5 hours, and filter to obtain a calcium-containing solution.

[0063] 2) Transfer the calcium-containing solution obtained in step 1) to another reactor, and continuously feed air into it to volatilize the ammonia gas in the solution, and gradually reduce the pH value of the solution to below 8.0, during which the reaction temperature is controlled at 80-85 After the reaction is completed, filter and wash to obtain calcium sulfate and reaction mother liquor.

[0064] 3) Step 2) obtained reaction mother liquor, returns step 1) as reaction liquid and recycles.

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Abstract

The invention discloses a processing method of a gypsum containing raw material. The processing method comprises following steps: (1) preparing a reaction solution containing a complexing agent, adding a gypsum containing raw material into the reaction solution to dissolve the raw material, and after reactions, separating the reaction products to obtain calcium slag and a calcium containing solution; and (2) removing the calcium slag, adjusting the pH value of the calcium containing solution by adding an acid or evaporating the ammonia gas until calcium sulfate is precipitated out, carrying out separation to obtain calcium sulfate and a reaction mother liquor, and returning the reaction mother liquor to the step (1).

Description

technical field [0001] The invention belongs to the field of chemical preparation, and in particular relates to a processing method for raw materials containing gypsum. Background technique [0002] Gypsum is an important inorganic raw material. The chemical and construction industries consume a large amount of mineral natural gypsum every year. At the same time, gypsum is also a common industrial by-product. The desulfurization and fertilizer industries produce hundreds of millions of tons of desulfurization gypsum and phosphogypsum every year, but these desulfurization gypsum And phosphogypsum contains more impurities, and the purity of calcium sulfate is lower, so it cannot be used as a raw material in the chemical and construction industries, and has less reuse value. Currently, it is mainly stockpiled. [0003] The main component of waste gypsum is calcium sulfate, and the impurities include calcium phosphate, calcium fluoride, calcium carbonate and silicon dioxide, etc...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01F11/46
CPCC01F11/468
Inventor 张超武占月任佳楠
Owner 北京中金瑞丰环保科技有限公司
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