Method for preparing sheet alumina using coal series kaolin rock or flyash as raw material

A technology of flaky alumina and kaolinite, applied in chemical instruments and methods, inorganic chemistry, aluminum compounds, etc., can solve problems such as inability to achieve economical and effective iron removal, difficult control of alumina crystal form, and strict process conditions. Achieve the effects of low cost, large surface thickness ratio, and cheap and easy-to-obtain raw materials

Inactive Publication Date: 2007-10-03
ZHEJIANG UNIV
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AI Technical Summary

Problems solved by technology

[0004] The main technical difficulties in preparing flaky alumina from coal-measure kaolinite or fly ash by acid method are: 1) purification and removal of impurity ions such as iron and manganese in the leach solution, especially the removal of iron ions, common iron removal Methods such as: extraction, ion exchange, recrystallization, alkali medium iron removal and other technologie

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0017] 1) Coal series kaolinite is dried, pulverized, dry magnetically separated, then calcined at 550°C for 4 hours, mixed with sulfuric acid with a mass percentage concentration of 20%, and extracted at 250°C for 1 hour; filtered, that is get aluminum sulfate solution;

[0018] 2) adjusting the pH of the aluminum sulfate solution prepared in step 1) to 3 with sodium hydroxide, and filtering to obtain a purified aluminum sulfate solution;

[0019] 3) Evaporating and concentrating the purified aluminum sulfate solution obtained in step 2) to saturation, adding formic acid according to the ratio of aluminum: formic acid molar ratio of 1:50, cooling to room temperature, depositing aluminum sulfate, filtering to obtain refined aluminum sulfate flakes; Mother liquor recycling.

[0020] 4) Put the refined flaky aluminum sulfate obtained in step 3) into a calciner for pyrolysis, raise the temperature to 400°C at a rate of 2°C / min, and keep it warm for 1 hour; then raise the tempera...

Embodiment 2

[0022] 1) Dry the fly ash, pulverize it, dry magnetically separate it, then calcinate it at 850°C for 1 hour, mix it with nitric acid with a mass percentage concentration of 35%, and extract it at 100°C for 4 hours; centrifuge to obtain Aluminum nitrate solution;

[0023] 2) adjusting the pH of the aluminum nitrate solution prepared in step 1) to 5 with sodium bicarbonate, and centrifuging to obtain a purified aluminum nitrate solution;

[0024] 3) Evaporate and concentrate the purified aluminum nitrate solution obtained in step 2) to saturation, add acetic acid according to the ratio of aluminum:acetic acid molar ratio of 1:300, cool to room temperature, precipitate aluminum nitrate, and centrifuge to obtain refined flake aluminum nitrate ; Mother liquor recycling.

[0025] 4) Put the refined flaky aluminum nitrate obtained in step 3) into a calciner for pyrolysis, raise the temperature to 500°C at a rate of 20°C / min, and keep it warm for 2 hours; then raise the temperature ...

Embodiment 3

[0027] 1) Coal series kaolinite is dried, pulverized, dry magnetically separated, then calcined at 650°C for 3 hours, mixed with hydrochloric acid with a concentration of 30% by mass, and extracted at 125°C for 4 hours; filtered, that is Get aluminum chloride solution;

[0028] 2) adjusting the pH of the aluminum chloride solution prepared in step 1) to 5 with sodium carbonate, and centrifuging to obtain a purified aluminum chloride solution;

[0029] 3) Evaporating and concentrating the purified aluminum chloride solution obtained in step 2) to saturation, adding propionic acid in a ratio of 1:50 by the molar ratio of aluminum: propionic acid, cooling to room temperature, and separating out aluminum chloride, which is filtered or centrifuged, The refined flake aluminum chloride is obtained, and the mother liquor is recycled;

[0030] 4) Put the refined flake aluminum chloride obtained in step 3) into a calciner, raise the temperature to 500°C at a rate of 2°C / min, and keep i...

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Abstract

A process for preparing flaky aluminum oxide from coal kaolinite or powdered coal ash includes such steps as pulverizing, magnetic separation, high-temp calcining, extracting in acid to obtain Al salt, purifying, refining, crystallizing, shaping and pyrolyzing.

Description

technical field [0001] The invention relates to the field of resource deep processing and utilization of coal series kaolinite or fly ash, in particular to a method for preparing flaky alumina using coal series kaolinite or fly ash as raw materials. Background technique [0002] Coal-measure kaolinite and fly ash are traditionally used as cement, ceramic raw materials, papermaking, coatings and fillers. In view of the serious shortage of bauxite resources in domestic and foreign markets, coal-measure kaolinite and fly ash have also been used in recent years. It is used as a raw material for the production of alumina. At present, because the product positioning is mainly low value-added products with primary processing, the resources are not fully utilized and the economic benefits are not obvious. [0003] In addition to the excellent physical and chemical properties of alumina itself, flaky alumina is also nano-scale or close to nano-scale on the thickness scale, and micron...

Claims

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Application Information

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IPC IPC(8): C01F7/20
Inventor 夏枚生叶瑛邬黛黛张平萍陈雪刚张孝彬程继鹏
Owner ZHEJIANG UNIV
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