A method for producing wollastonite and alumina by hydrothermal method of fly ash alkali leaching and sintering

A technology of fly ash and wollastonite, which is applied in the field of comprehensive utilization of fly ash solid waste and mineral processing, and can solve the problems of great impact and scarcity of resources and the environment

Active Publication Date: 2016-08-24
NORTHEASTERN UNIV ENG & RES INST CO LTD
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, my country's bauxite resources are quite scarce, and bauxite reserves only account for about 5% of the world's total reserves, and most of them are low-grade diaspore-type bauxite that is difficult to handle. Purchasing restriction policy, bauxite resource problem has become the biggest bottleneck for the sustainable development of my country's alumina and aluminum industry
[0005]Wollastonite produced by traditional technology is generally obtained by beneficiation of wollastonite raw ore, and it is also hydrothermally synthesized by firing limestone and silica powder from limestone. Resources and the environment are highly impacted
[0006] Existing various processes for producing aluminum hydroxide or aluminum oxide with high alumina fly ash all produce a large amount of silicon-calcium slag or silicon slag, and these silicon-calcium slag or silicon The large-scale and rational utilization of slag has become a huge bottleneck in the development of alumina production technology from various fly ash

Method used

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  • A method for producing wollastonite and alumina by hydrothermal method of fly ash alkali leaching and sintering

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0037] 1. Chemical beneficiation: Put the fly ash into the batching tank with chemical beneficiation solvent for batching. The chemical beneficiation solvent contains Na 2 O 30g / L, containing SiO 2 ≤5g / L; the proportion of ingredients is 3 according to the weight ratio of chemical beneficiation solvent and fly ash; then chemical beneficiation treatment, the reaction temperature is 70°C, and the reaction time is 600 min; the obtained chemical beneficiation slurry is continuously separated through a horizontal belt filter and washing to obtain the washing filter residue and crude sodium silicate solution; the washing filter residue is washed again to make a fly ash concentrate with a water weight content of 45%;

[0038] Na in the obtained crude sodium silicate solution 2 O concentration is 30g / L, SiO 2 The concentration is 15g / L; the crude sodium silicate solution is refined by leaf filtration to obtain a refined sodium silicate solution with solid floating matter less than 1...

Embodiment 2

[0052]Method is with embodiment 1, and difference is:

[0053] (1) The chemical beneficiation solvent contains Na 2 O 90g / L; the proportion of ingredients is 6 according to the weight ratio of chemical beneficiation solvent and fly ash; the reaction temperature of chemical beneficiation treatment is 100°C, and the reaction time is 200 min; the washed filter residue is washed again to make a powder with a water weight content of 40%. coal ash concentrate;

[0054] Na in the obtained crude sodium silicate solution 2 O concentration is 80g / L, SiO 2 The concentration is 30g / L;

[0055] (2) Na in sodium aluminate solution 2 O concentration is 210g / L, Na 2 O+K 2 O and Al 2 o 3 The molar ratio is 2.8, the mixing ratio of fly ash concentrate and sodium aluminate solution is based on the Na in all materials 2 O+K 2 O and Al 2 o 3 The molar ratio is 1.56, the leaching temperature is 265°C, and the reaction time is 60min; 2 The O concentration is controlled at 145g / L; the de...

Embodiment 3

[0065] Method is with embodiment 1, and difference is:

[0066] (1) The chemical beneficiation solvent contains Na 2 O 120g / L; the proportion of ingredients is 9 according to the weight ratio of chemical beneficiation solvent and fly ash; the reaction temperature of chemical beneficiation treatment is 120°C, and the reaction time is 30min; the washed filter residue is washed again to make pulverized coal with a water weight content of 30% ash concentrate;

[0067] Na in the obtained crude sodium silicate solution 2 O concentration is 120g / L, SiO 2 The concentration is 60g / L;

[0068] (2) Na in sodium aluminate solution 2 O concentration is 245g / L, Na 2 O+K 2 O and Al 2 o 3 The molar ratio is 3.2, the mixing ratio of fly ash concentrate and sodium aluminate solution is based on the Na in all materials 2 O+K 2 O and Al 2 o 3 The molar ratio is 1.6, the leaching temperature is 280°C, and the reaction time is 30min; 2 The O concentration is controlled at 165g / L; the d...

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Abstract

The invention relates to a method for producing wollastonite and aluminum oxide through a fly ash alkali leaching and sintering hydrothermal method. The method comprises the following steps: (1) after fly ash is mixed with a chemical mineral separation solvent, performing chemical mineral separation treatment and washing to prepare a fly ash concentrate; (2) leaching the fly ash concentrate with a sodium aluminate solution; (3) preparing raw slurry; (4) sintering and preparing a clinker; (5) dissolving, separating and washing the clinker; (6) preparing xonotlite precursor raw slurry; (7) performing hydro-thermal synthesis to prepare a xonotlite precursor; (8) performing hydro-thermal synthesis to prepare xonotlite slurry; (9) preparing wollastonite. According to the method, the problems of high consumption of limestone, high energy consumption and large amount of slag in the prior art are effectively solved; by the comprehensive utilization of the fly ash, both the wollastonite and the aluminum oxide can be produced, the substitution of both silicon mineral resources and bauxite mineral resources is realized, soil and other resources are saved, and the large-scale economic production can also be realized.

Description

technical field [0001] The invention belongs to the technical field of comprehensive utilization of fly ash solid waste and mineral processing, and in particular relates to a method for producing wollastonite and alumina by a hydrothermal method of alkali leaching and sintering of fly ash. Background technique [0002] Some coal fields in central and western Inner Mongolia and northern Shanxi are rich in high-alumina coal resources, with prospective reserves of nearly 100 billion tons, equivalent to about 15 billion tons of high-alumina fly ash, which is equivalent to the current reserves of bauxite in my country More than 8 times of that, and the alumina content in some fly ash can reach 40~50%. This kind of fly ash is generally called high aluminum fly ash. Fly ash is the main solid waste from the perspective of power generation in power plants, but the alumina content in the high-alumina fly ash produced by the combustion of high-alumina coal can reach 35-45%, some even as...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01F7/02C01B33/24C01B39/02
CPCC01B33/24C01B39/02C01F7/02
Inventor 李光柱崔德成涂赣峰于海燕潘晓林毕诗文黎娜
Owner NORTHEASTERN UNIV ENG & RES INST CO LTD
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