Method for extracting high-purity alumina from pulverized fuel ash of pulverized coal furnace

A high-purity alumina and fly ash technology, applied in chemical instruments and methods, inorganic chemistry, aluminum compounds, etc., can solve the problems of low alumina and white mud extraction rate, large amount of residue, complex process, etc. Equipment investment, high purity, simple activation effect

Inactive Publication Date: 2017-07-21
CHINA SHENHUA ENERGY CO LTD +1
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0006] The purpose of the present invention is to provide a simple process and low energy consumption from pulverized coal furnace powder in order to overcome the technical problems of low extraction rate of alumina and lime mud, high energy consumption, complex process and large amount of residue in the prior art. Method for extracting high-purity alumina and lime mud from coal ash

Method used

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  • Method for extracting high-purity alumina from pulverized fuel ash of pulverized coal furnace
  • Method for extracting high-purity alumina from pulverized fuel ash of pulverized coal furnace
  • Method for extracting high-purity alumina from pulverized fuel ash of pulverized coal furnace

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example 1

[0061] (1) Mix 1200:1 fly ash with polypropylene alcohol dispersant and grind to below 2μm

[0062] (2) the pulverized coal ash and 30% hydrochloric acid in the step (1) are mixed evenly by the solid-to-liquid ratio of 1:12 by the fly ash quality (g) and the hydrochloric acid volume (ml) ratio, in airtight stirring Under the conditions, leaching at 160°C for 2 hours, filtering, analyzing and testing the filtrate, the dissolution rate of alumina is 95%.

[0063] (3) feed hydrogen chloride gas to the thick aluminum chloride solution gained in step (2) to supersaturation, control the temperature to be no more than 50° C., filter to obtain thick crystallized aluminum chloride, and the crystallization rate is above 99%; The crystalline aluminum chloride is washed 3 times to obtain high-purity crystalline aluminum chloride; the filtrate and washing liquid in this process are evaporated at low temperature to prepare hydrogen chloride gas, which is reused in step (3).

[0064] (4) Ca...

example 2

[0067] (1) Grinding the fly ash below 4 μm;

[0068] (2) The pulverized coal ash of step (1) and 25% hydrochloric acid are mixed evenly at a solid-to-liquid ratio of 1:10 by the fly ash mass (g) and hydrochloric acid volume (ml) ratio, and the leaching at 140°C for 1 hour, filtered, and the filtrate was analyzed and tested, and the dissolution rate of alumina was 88%;

[0069] (3) After evaporating the crude aluminum chloride solution obtained in step (2) to supersaturation, feed hydrogen chloride gas to supersaturation, control the temperature not to exceed 50°C, and filter to obtain coarse crystalline aluminum chloride, the crystallization rate of aluminum chloride More than 99.10%; the crystalline aluminum chloride is washed twice with concentrated hydrochloric acid to obtain high-purity crystalline aluminum chloride.

[0070] (4) Roasting the high-purity crystalline aluminum chloride obtained in step (3) at a temperature of 1000°C for 2 hours to obtain the product high-pu...

example 3

[0074] (1) Grind the fly ash to 2 μm or less.

[0075] (2) The pulverized coal ash of step (1) and 30% hydrochloric acid are mixed uniformly at a solid-to-liquid ratio of 1:10 by the fly ash mass (g) and hydrochloric acid volume (ml) ratio, and the condition of airtight stirring leaching at 170°C for 2 hours, filtered, and the filtrate was analyzed and tested, and the dissolution rate of alumina was 99%.

[0076] (3) Pass into hydrogen chloride gas to the aluminum chloride solution gained in step (2), control the temperature not to exceed 50°C, control the acidity of the solution at 8mol / l, filter to obtain a part of high-purity crystalline aluminum chloride, and the crystallization rate is 65%. Continue to feed hydrogen chloride gas into the filtrate until it is supersaturated, filter the obtained crude crystalline aluminum chloride, wash the above-mentioned crude crystalline aluminum chloride 3 times with concentrated hydrochloric acid, and obtain another part of high-purity...

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Abstract

The invention discloses a method for extracting high-purity alumina and white mud from pulverized fuel ash of a pulverized coal furnace. The method comprises the process steps of fine crushing of the pulverized fuel ash of the pulverized coal furnace, acid extraction of aluminum oxide, solid-liquid separation of aluminum oxide and white mud (silicon oxide), precipitation and purification (removal of impurities such as calcium, iron and magnesium) of aluminum chloride crystals, calcination of crystallized aluminum chloride, precipitation of aluminum chloride crystal at a calcination stage and hydrochloric acid and hydrogen chloride gas recycling at a purification stage and the like. The prepared alumina and white mud are high value-added products, the alumina extracting rate of the pulverized fuel ash is 85% or above, the white mud can be used for preparing molecular sieves and plastic fillers, the pulverized fuel ash is thoroughly used up, the technological process is short, the materials are recycled, the energy consumption is low, no secondary pollution is produced, and cyclic economy is achieved.

Description

technical field [0001] The invention belongs to the technical field of solid waste recovery and utilization-circular economy, and specifically relates to a method for extracting high-purity alumina from fly ash of a pulverized coal furnace. Background technique [0002] In recent years, metal aluminum and aluminum alloys have become the second most important metals in the world after steel. The main mineral source is bauxite. The distribution of bauxite resources in the world is concentrated and uneven (including Guinea, Australia, Jamaica, etc. , Brazil accounted for 70% of the world's total reserves). my country is the world's largest consumer of primary aluminum, but my country's high-quality bauxite resources are scarce, and its dependence on imports has reached 50%, which makes my country very passive in terms of aluminum industry prices, which will affect the security of the entire national economy. Therefore, it is necessary to improve my country's bauxite mining tec...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01F7/22C01B37/00C01B39/00C04B18/04C04B28/12
CPCC01B37/00C01B39/00C01F7/22C01P2006/80C04B18/0427C04B28/12C04B18/12C04B14/06Y02W30/91
Inventor 郭昭华张小东王永旺徐靓陈东图亚白健许立军王丽萍
Owner CHINA SHENHUA ENERGY CO LTD
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