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Impurity removing method in process of preparing alumina from fly ash by utilizing acid method

A technology for alumina and fly ash, applied in the field of impurity removal, can solve the problems of difficult separation of impurity iron, complicated alumina process, etc., and achieve the effects of large slag particles and easy removal, remarkable iron removal effect and fast precipitation speed.

Inactive Publication Date: 2013-12-18
XIAN AEROSPACE PROPULSION TESTING TECHN INST
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Problems solved by technology

[0008] In order to solve the technical problems that the existing acid method for preparing alumina is complex and the impurity iron is difficult to separate, the present invention provides a method for removing impurities in the process of preparing alumina from fly ash by using an acid method. Sodium carbamate or potassium dimethyl dithiocarbamate is used as a precipitant to remove iron ions in the acidic aqueous solution of aluminum salts in the process of producing aluminum oxide from fly ash. The iron removal effect is remarkable, the process is simple, easy to operate, and The precipitant can be processed and reused, and the process cost is low

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  • Impurity removing method in process of preparing alumina from fly ash by utilizing acid method

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Embodiment 1

[0048] 1) At room temperature, the precipitant (sodium dimethyldithiocarbamate) is pressed by Fe 3+ :Na + The molar ratio is 1:2, and it is added to the acidic aqueous solution of aluminum salt in the process of producing alumina from acid-process fly ash under stirring. The reaction produces black precipitate (ferric dimethyl dithiocarbamate), which is separated by filtration to obtain iron-removed Aluminum salt solution.

[0049] 2) The aluminum salt solution after iron removal is crystallized and separated by filtration to obtain aluminum salt crystals.

[0050] 3) Roasting crystalline aluminum salt to produce alumina.

[0051] 4) Add the black precipitate iron dimethyl dithiocarbamate obtained in step 1) to the solution after the aluminum salt crystallization in step 2), add sodium hydroxide, adjust the pH value to 10, and generate a red precipitate (hydrogen iron oxide), separated by filtration to obtain a filtrate containing sodium dimethyldithiocarbamate, which is us...

Embodiment 2

[0053] 1) At room temperature, the precipitant (potassium dimethyldithiocarbamate) was 3+ : K + The molar mass ratio is 1:4, and it is added to the acidic aqueous solution of aluminum salt in the process of producing alumina from acid-process fly ash under stirring. The reaction produces black precipitate (ferric dimethyl dithiocarbamate), which is separated by filtration to obtain iron removal After aluminum salt solution.

[0054] 2) The aluminum salt solution after iron removal is crystallized and separated by filtration to obtain aluminum salt crystals.

[0055] 3) Roasting crystalline aluminum salt to produce alumina.

[0056] 4) Add the black precipitate (ferric dimethyl dithiocarbamate) obtained in step 1) to the solution after the aluminum salt crystallization and precipitation in step 2, and add potassium hydroxide to adjust the pH value to 13, and generate a red precipitate (hydrogen iron oxide), separated by filtration to obtain a filtrate containing potassium di...

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Abstract

The invention relates to an impurity removing method in a process of preparing alumina from fly ash by utilizing an acid method. The method comprises following steps: by utilizing the characteristic that iron (III) dimethyldithiocarbamate does not precipitate in an alkaline environment condition, adjusting the pH value of the system to the alkaline range by adding ammonia water, ammonia gas, or sodium hydroxide to precipitate iron in the form of iron hydroxide, then subjecting the reaction liquid to a filtration separation treatment so as to obtain an aluminium salt solution without iron, crystallizing the aluminium salt solution without iron to precipitate, filtrating to separate so as to obtain aluminium salt crystals and filtration liquid, burning the aluminium salt crystals so as to obtain purified alumina. The method solves the technical problems of complicated technologies and difficult separation of impurities in the conventional acid method, and has the advantages of prominent iron-removing effect, simple technology, easy operation, and low technology cost.

Description

technical field [0001] The invention relates to a method for removing impurities in the process of preparing alumina from fly ash by adopting an acid method. Background technique [0002] Thermal power generation occupies a dominant position in my country's power generation structure, and coal-fired thermal power generation occupies an absolute proportion in thermal power generation. Fly ash is a solid waste discharged from coal-fired power plants. [0003] In recent years, with the development of the power industry, the emission of fly ash has increased sharply. According to the report of China Coal Industry Association in January 2009, the total coal production in my country in 2008 was 2.716 billion tons, most of which were used for power generation , the annual discharge of fly ash in my country has exceeded 200 million tons, and the cumulative stockpiles have exceeded 2.5 billion tons, occupying a large amount of arable land and polluting the environment on a large scale...

Claims

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Application Information

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IPC IPC(8): C01F7/02B09B3/00
Inventor 杨超李宁吴金梁兴国兰海平郭新峰黄兴曾伟高旋张建宁张文郑攀峰
Owner XIAN AEROSPACE PROPULSION TESTING TECHN INST
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