Method for producing alumina through bauxite acid process

Abstract

The invention relates to a method for producing alumina through a bauxite acid process, which comprises the following steps that: (1) alumyte with the Al-Si ratio of 1.5 to 5 or the ferric oxide content of 10 to 50 percent is selected as the raw material, crushed and put into a closed container to be leached, and hydrogen chloride gas is blown in during the leaching process; (2) TBP and sulfonated kerosene are added into leachate to be extracted, and extraction phase and the raffinate phase are obtained after extraction; (3) the aluminum chloride solution is separated from the extraction phase, and then the aluminum chloride solution is heated and decomposed, the pyrolysis temperature is 400 to 900DEG C, and the pyrolysis time is 5 to 60min, and alumina and hydrogen chloride gas are obtained. The extraction phase is back extracted to obtain ferric chloride solution and pyrolysed to obtain ferric oxide. The method for producing alumina through bauxite acid process realizes the effective treatment to low-grade and high-iron bauxite ore, has high resource utilization rate, realizes the integrated utilization of aluminum, iron, silicon and other valuable elements; and that the hydrogen chloride is added in through a continuous spraying and blowing method during the leaching process can improve the ore blending and provide the production capability.

Description

technical field [0001] The invention relates to a production method of alumina, in particular to a method for producing alumina by a bauxite acid method. technical background [0002] At present, almost all enterprises using bauxite resources to produce alumina use the alkaline method, of which the Bayer method is the most important method for producing alumina. However, the production of alumina by the Bayer process requires a higher grade of bauxite. When the grade of the ore is low, the aluminum in the mineral will combine with the silicon-containing mineral to form hydrated sodium aluminosilicate, which will lead to low extraction efficiency of aluminum and redness. The emergence of problems such as large amount of mud, taking bauxite with an aluminum-silicon ratio of 5 as an example, the theoretical dissolution rate of alumina in the ore during the production of alumina by the Bayer process is only about 80%, resulting in a sharp drop in aluminum yield , The comprehens...

AI Technical Summary

Problems solved by technology

However, the production of alumina by the Bayer process requires a higher grade of bauxite. When the grade of the ore is low, the aluminum in the mineral will combine with the silicon-containing mineral to form hydrated sodium aluminosilicate, which will lead to low extraction efficiency of aluminum and redness. The emergence of problems such as large amount of mud, taking bauxite with an aluminum-silicon ratio of 5 as an example, the theoretical dissolution rate of alumina in the ore during the production of alumina by the Bayer process is only about 80%, resulting in a sharp drop in aluminum yield , the comprehensive utilization rate of resources is low

A kind of stripping method of diaspore ore (CN101289205A) invented by Aluminum Corporation of China, but can not fundamentally solve the shortcomings such as large amount of red mud of middle and low grade bauxite, resource utilization rate, and a large amount of red mud Mud cannot be applied, takes up a lot of land, and causes serious soil pollution

[0003] In my country's bauxite resources, the total reserves of minerals with high iron content (>10%) exceed 800 million tons. In the production process of Bayer process alumina using high-iron bauxite as raw material, the higher iron content in the ore (iron oxide content is 10% to 50%) will lead to problems such as large amount of dissolved red mud, high iron content in red mud and difficult separation

However, in the existing red mud iron separation process, the extraction efficiency of iron oxide is mostly about 20% to 30%, and most of the iron elements in red mud have not been effectively utilized.

Aiming at the shortcomings of the Bayer method, China Great Wall Aluminum Corporation invented a method for the separation and comprehensive utilization of aluminum and iron of high-iron bauxite (CN1806930A), and a method for extracting iron and aluminum from high-iron bauxite invented by Guiyang Aluminum and Magnesium Design Research Institute (CN1766128A) , a kind of combined production method (CN101337683A) that Lu Huimin et al. invented using high-iron bauxite as raw material to prepare multiple products, but all of the above have shortcomings such as complicated process and low comprehensive utilization rate of valuable elements

Images