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Method for extracting alumina from coal gangue

A technology of coal gangue and alumina, which is applied to the preparation of alumina/hydroxide and alumina/hydroxide, and can solve the problems that are not conducive to the preparation of high-purity alumina

Inactive Publication Date: 2009-06-10
CHANGCHUN CHAOWEI NEW MATERIALS TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The lime milk added by this method is easy to cause the reaction to generate calcium carbonate precipitation, which is not conducive to the preparation of high-purity alumina

Method used

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  • Method for extracting alumina from coal gangue

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Effect test

Embodiment 1

[0020] Take 2500g coal gangue, mechanically crush it to ≤200 mesh, and put it into a fluidized bed furnace for calcination. The calcination temperature is 600℃, and the calcination time is 3h. Then use a magnetic separator to remove iron; weigh the gangue lime after preliminary iron removal Put 500g of the material in the reaction kettle, add 1500ml of 25% hydrochloric acid, control the heating temperature at 100°C, and keep stirring for 2h. After the acid dissolution is completed, the mixed solution is cooled to 90°C and placed in a sedimentation tank. The upper layer liquid is directly filtered by suction, the filtrate is sent to the crystallization reaction kettle, the lower layer slag mixture is washed, discarded, and the lotion is returned It is reused in the acid-dissolving reactor, and the crystalline aluminum chloride is separated after crystallization. The obtained crystalline aluminum chloride is heated to 500° C. and calcined at low temperature to obtain crude alumina. ...

Embodiment 2

[0023] Take 2500g of coal gangue, mechanically crush it to 200 mesh, and put it into a fluidized bed furnace for calcination. The calcination temperature is 600℃, and the calcination time is 3h. Then use a magnetic separator to remove iron; weigh the gangue lime material after preliminary iron removal 500g was placed in the reaction kettle, 1300ml of hydrochloric acid with a concentration of 30% was added, the heating temperature was controlled at 90°C, and the reaction was continued for 1.5h. After the acid dissolution is completed, the mixed solution is cooled to 90°C and placed in a sedimentation tank. The upper layer liquid is directly filtered by suction, the filtrate is sent to the crystallization reaction kettle, the lower layer slag mixture is washed, discarded, and the lotion is returned It is reused in the acid-dissolving reactor, and the crystalline aluminum chloride is separated after crystallization. The obtained crystalline aluminum chloride is heated to 450 DEG C, a...

Embodiment 3

[0026] Take 2500g of coal gangue, mechanically crush it to 200 mesh, and put it into a fluidized bed furnace for calcination. The calcination temperature is 600℃, and the calcination time is 3h. Then use a magnetic separator to remove iron; weigh the gangue lime material after preliminary iron removal Put 500g in the reaction kettle, add 1400ml of sulfuric acid with a concentration of 45%, control the heating temperature at 105°C, and keep stirring for 1h. After the acid dissolution is completed, the mixed solution is cooled to 90°C and placed in a sedimentation tank. The upper layer liquid is directly filtered by suction, the filtrate is sent to the crystallization reaction kettle, the lower layer slag mixture is washed, discarded, and the lotion is returned It is reused in the acid-dissolving reactor, and the crystalline aluminum sulfate is separated after crystallization. The obtained crystalline aluminum sulfate is heated to 800°C, and after low-temperature calcination, coarse...

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Abstract

The invention mainly relates to a method for extracting alumina from coal gangue. The coal gangue is ground, and then is calcined through a fluidized furnace and iron is removed through a magnetic separator, the coal gangue with the iron removal reacts with an acid to obtain an aluminum chloride solution without silicon impurities, the solution containing the aluminum is concentrated and crystallized and then is subjected to low-temperature calcination to obtain crude aluminum oxide, then the crude aluminum oxide reacts with sodium hydroxide to obtain a sodium aluminate mother solution, impurities such as iron and titanium are removed, an aluminum hydroxide crystal seed is added to the mother solution, and carbon dioxide gas is introduced for seed precipitation to obtain an aluminum hydroxide precipitate, and metallurgical grade alumina can be obtained through the calcinations. The method does not use any auxiliary agent at normal pressure, and uses hydrochloric acid and sulfuric acid to directly leach and extract alumina; the content of the alumina prepared by the method can reach more than 99 percent; and the method has the advantages of simple process flow, adequate raw material sources, less energy consumption, low cost, and high utilization value of the coal gangue.

Description

Technical field: [0001] The invention belongs to the refined and comprehensive utilization of coal gangue, and particularly relates to a method for extracting alumina from coal gangue. Background technique: [0002] Coal gangue is referred to as gangue, but it is a kind of black rock with low carbon content and relatively hard that is associated with coal seam during coal formation and becomes waste during coal production. According to incomplete statistics, my country’s coal gangue stockpiles over the years have reached 3 billion tons, occupying about 55 million hectares of land. 2 Moreover, the amount of coal mine gangue is still increasing at an annual rate of about 11.5 billion tons; coal gangue contains a large amount of aluminum resources. Under the premise that my country’s aluminum resources are severely lacking, this part of "turning costs into treasures" has become Important issues affecting economic and social benefits. [0003] The methods related to the present inven...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01F7/02C01F7/30
Inventor 魏存弟杨殿范徐少南陈智莲于德利赵以辛吴永峰孙双李晓兵
Owner CHANGCHUN CHAOWEI NEW MATERIALS TECH
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