Method for preparing metal aluminum through microwave chlorination of coal ash

A technology of fly ash and metal aluminum, applied in the direction of improving process efficiency, etc., can solve the problems of complicated production process, low cost of sintering raw materials, increased production cost, etc., achieve fast heating speed, small equipment footprint, and high heating uniform effect

Active Publication Date: 2016-10-26
NORTHEASTERN UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Such as patents CN1923695A, CN1920067A, CN101045543A, CN101397146A, etc., but in the production process, the method of acid dissolution first and then alkali dissolution complicates the production process and increases the production cost
[0007] There are many shortcomings in the existing technology of producing al

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  • Method for preparing metal aluminum through microwave chlorination of coal ash

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[0044] Example 1

[0045] A method for preparing metal aluminum by microwave chlorination of fly ash, comprising the following steps:

[0046] Step 1. Microwave heating and chlorination decomposition of fly ash:

[0047] Add carbon to the high-alumina fly ash containing 25% alumina mass fraction, mix and pulverize together, then pass chlorine gas, the pressure is normal pressure, and the microwave frequency is 2.5GHz microwave fluidized bed heating for 10min, reaching 800 ℃, constant temperature for 20min, fully decompose the fly ash to obtain a variety of chlorinated mixed gases containing aluminum chloride; wherein, by mass ratio, fly ash: carbon = 1: 2, fly ash: chlorine = 1: 4 ;

[0048] Step 2, separation and purification, sedimentation of aluminum chloride:

[0049] (1) The purification process of impurity removal is to remove impurities from various chlorinated mixed gases containing aluminum chloride through a three-stage condensation recovery device to obtain anhyd...

Example Embodiment

[0058] Example 2

[0059] A method for preparing metal aluminum by microwave chlorination of fly ash, comprising the following steps:

[0060] Step 1. Microwave heating and chlorination decomposition of fly ash:

[0061] Add carbon to the high-alumina fly ash containing 30% alumina mass fraction, mix and pulverize together, then pass chlorine gas, the pressure is normal pressure, and the microwave frequency is 2.3GHz microwave fluidized bed heating for 30min, reaching 900 ℃, constant temperature for 10min, fully decompose the fly ash to obtain a variety of chlorinated mixed gases containing aluminum chloride; wherein, by mass ratio, fly ash: carbon = 1: 1.5, fly ash: chlorine = 1: 3 ;

[0062] Step 2, separation and purification, sedimentation of aluminum chloride:

[0063] (1) The purification process of impurity removal is to remove impurities from various chlorinated mixed gases containing aluminum chloride through a three-stage condensation recovery device to obtain anh...

Example Embodiment

[0072] Example 3

[0073] A method for preparing metal aluminum by microwave chlorination of fly ash, comprising the following steps:

[0074] Step 1. Microwave heating and chlorination decomposition of fly ash:

[0075] Add carbon to the high-alumina fly ash containing 30% alumina mass fraction, mix and pulverize together, then pass chlorine gas, the pressure is normal pressure, and the microwave frequency is 2.5GHz microwave fluidized bed heating for 5min, reaching 700 ℃, constant temperature for 30min, fully decompose the fly ash to obtain a variety of chlorinated mixed gases containing aluminum chloride; wherein, by mass ratio, fly ash: carbon = 1: 3, fly ash: chlorine = 1: 5 ;

[0076] Step 2, separation and purification, sedimentation of aluminum chloride:

[0077] (1) The purification process of impurity removal is to remove impurities from various chlorinated mixed gases containing aluminum chloride through a three-stage condensation recovery device to obtain anhydr...

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Abstract

Disclosed is a method for preparing metal aluminum through microwave chlorination of coal ash. The method specifically comprises the following steps that carbon is added into the high-aluminum coal ash, the carbon and the coal ash are mixed evenly, and chlorine is led in; heating is conducted for 5-60 min through a microwave fluidized bed to 300-1200 DEG C, and constant temperature is kept for 10-60 min; the high-aluminum coal ash is fully decomposed, and various chlorinated mixed gases containing aluminum chloride are obtained; then through purification and rectification, aluminum chloride anhydrous with the purity being 99% or above is obtained; a sodium hydroxide solution is added to the aluminum chloride anhydrous to obtain an intermediate product, and through precipitation, filtration and solid-liquid separation, aluminum hydroxide precipitates and a sodium chloride solution are obtained; aluminum hydroxide is precipitated, calcination is conducted at the temperature of 800-1200 DEG C, and aluminum oxide is generated through decomposition; and the aluminum oxide is electrolyzed to obtain the metal aluminum. According to the method, the technological process is simple, and a clean technology with low energy consumption is achieved. Chlorine and sodium hydroxide generated by a system are both recycled, and effective full element separation utilization can also be achieved. No discharging of waste water or waste acid or waste alkali liquor occurs in the system, and zero discharging of three wastes is achieved basically.

Description

technical field [0001] The invention belongs to the technical field of aluminum production, in particular to a method for preparing metallic aluminum by microwave chlorination of fly ash. Background technique [0002] Fly ash is a solid waste after coal combustion. The alumina content in fly ash is equivalent to that in my country's medium and low-grade bauxite. High-alumina fly ash is a substitute for bauxite in my country's alumina industry. potential resources. Fly ash is the main source of suspended particulate matter, causing regional air pollution and endangering human health. Long-term stockpiling of fly ash will also pollute soil and water bodies, threatening human health and wasting a lot of water resources. Technically, the application research of fly ash is basically divided into three levels: low, medium and high: the low level refers to the use in road and dam construction, etc.; the middle level refers to the use as building materials; the high level refers to...

Claims

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Application Information

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IPC IPC(8): C22B7/00
CPCC22B7/002C22B7/006Y02P10/20
Inventor 张廷安吕国志王龙豆志河刘燕张子木王艳秀赵秋月
Owner NORTHEASTERN UNIV
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