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Method for extracting aluminum oxide from coal gangue and co-producing active calcium silicate

A technology of active calcium silicate and coal gangue, which is applied in the directions of alumina/aluminum hydroxide, silicate, alkaline earth metal silicate, etc., can solve the problems of waste of resources, poor economy, cumbersome process, etc., and save production costs. , reduce energy consumption and improve economic efficiency

Active Publication Date: 2011-01-12
TONGFANG ENVIRONMENT
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Problems solved by technology

The above three technical patents are all alkali methods. Due to the high silica content in coal gangue, the direct extraction of alumina requires a lot of alkali. Although the patent application number 200710133214.6 produces silicic acid as a by-product, the process is very cumbersome and economical.
The Chinese invention patent application number is 200410062965.X "a process for producing alumina", which discloses the activation and pre-desilication of kaolinite, fly ash and other raw materials in advance, and then uses limestone self-crushing and sintering method to mix and roast, carbonic acid Sodium dilute alkali solution leaching, leaching solution complexation reaction purification, carbonization to obtain aluminum hydroxide, and then high-temperature roasting into alumina, this invention firstly carried out pre-desilication, which reduced the consumption of alkali, but did not remove the The silicon dioxide is utilized, resulting in a waste of resources. In addition, the temperature of kaolinite roasting activation and limestone self-crushing and sintering in this invention is relatively high, and the energy consumption is relatively large.

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  • Method for extracting aluminum oxide from coal gangue and co-producing active calcium silicate
  • Method for extracting aluminum oxide from coal gangue and co-producing active calcium silicate

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Embodiment Construction

[0036] Referring to accompanying drawing, production step of the present invention is:

[0037] ① Raw material selection containing Al 2 o 3 42.93%, SiO 2 51.92% coal gangue, after being ground to 200 meshes, is activated by high-temperature roasting at a roasting temperature of 950°C and a holding time of 2 hours.

[0038] ② After the roasted clinker is naturally cooled, add 15% sodium hydroxide solution according to the mass ratio of coal gangue to NaOH of 1:0.5, and carry out desiliconization reaction at 110°C for 2 hours. After the reaction is finished, filter and separate to obtain the filtrate sodium silicate solution and filter cake desiliconized coal gangue.

[0039] ③ Add lime milk to the filtrate sodium silicate solution for causticization reaction, the amount of lime milk added is based on CaO and SiO 2 The molar ratio is 1.1, and the reaction temperature is 90°C. After reacting for 1 hour, filter and separate. The filtrate is sodium hydroxide solution, which is...

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Abstract

The invention provides a method for extracting aluminum oxide from coal gangue and co-producing active calcium silicate, and relates to the technical field of producing aluminum oxide and the active calcium silicate. The method comprises the following steps of: grinding coal gangue, and roasting and activating the ground coal gangue; performing alkali soluble desilication of coal gangue clinker to obtain desilication coal gangue and solution of sodium silicate; performing causticizing reaction of the solution of sodium silicate to obtain water-containing calcium silicate and solution of sodium hydroxide, and drying the water-containing calcium silicate to obtain micro powder of active calcium silicate; adding limestone and solution of sodium carbonate into the desilication coal gangue, and ball-grinding the mixed solution to obtain raw slurry; dissolving out the clinker which is obtained by roasting the raw slurry with water to obtain crude solution of sodium aluminate and silicon and calcium residues, wherein the silicon and calcium residues can be used as cement raw materials after post-treatment; performing deep desilication of the crude solution of sodium aluminate to obtain the purified solution of sodium aluminate; feeding CO2 into the purified solution of sodium aluminate to obtain aluminum hydroxide and solution of sodium carbonate; and calcining the aluminum hydroxide to obtain the aluminum oxide products. The method has the advantages of simple process, low production cost, low energy consumption and little consumption of raw materials; in addition, by the method, two kinds of silicon-containing byproducts are simultaneously produced, and no waste is generated.

Description

technical field [0001] The invention relates to the technical field of alumina co-production active calcium silicate production, in particular to a method for extracting alumina co-production active calcium silicate from coal gangue. Background technique [0002] Coal gangue is the solid waste with the largest discharge and stacking volume in my country at present, causing great environmental pollution and waste of resources. The mineral composition of coal gangue is mainly kaolinite, in which alumina and silica are relatively high, and it is a potential mineral resource. With the country's increasing demand for metallurgical-grade alumina and the decreasing reserves of bauxite in my country, aluminum-containing mineral resources such as fly ash and coal gangue produced by industrial production are used to replace natural bauxite to produce alumina, etc. Industrial products, and the formation of a coal-electricity-metallurgy circular economy industrial chain, has increasingl...

Claims

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Application Information

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IPC IPC(8): C01F7/02C01B33/24C04B7/14
CPCY02P40/10
Inventor 孙俊民姚强张战军曹慧芳张晓云孟德润汤乐萍项光明
Owner TONGFANG ENVIRONMENT
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