Process for producing aluminum oxide from alumyte

Abstract

The invention provides a method for producing alumina with bauxite and relates to a technical method for producing alumina by adopting medium and low grade high silicon bauxite. The method is characterized in that the bauxite is directly soaked in liquid caustic with high concentration for obtaining aluminosilicate minerals in the bauxite to realize chemical desiliconization; the solid after soaked out and separated is ore concentrate which enters Bayer process procedure to produce the alumina. In the method for producing alumina with bauxite of the invention, the bauxite need not to be calcined and can be directly soaked by the liquid caustic under the condition of normal pressure or pressurizing for obtaining the aluminosilicate minerals such as kaolinite, illite, and the like, in the bauxite to realize the chemical desiliconization; the principle is that the liquid caustic can decompose gangue minerals such as the kaolinite, the illite, and the like, in the high silicon bauxite at certain concentration and temperature without baking the bauxite, which leads a majority of SiO2 in the bauxite to enter the solution for separating so as to realize the aim of desiliconization.

Description

A method for producing alumina from bauxite technical field The invention relates to a method for producing alumina from bauxite, which relates to a process method for producing alumina using medium and low-grade high-silicon bauxite. Background technique Most of the bauxite in my country is of medium and low-grade high-silicon and low-iron diaspore type with A / S of 4 to 7, and the reserves of high-grade bauxite with A / S greater than 9 are very small. In recent years, with the increase of alumina With the extreme expansion of production scale, high-grade ore is almost exhausted. In order to produce alumina by the more economical Bayer process, my country has carried out a lot of research and experiments on the beneficiation of high-silicon bauxite. At present, bauxite floating The separation and desiliconization technology has been applied industrially, which has opened up an effective way for my country's high-silicon bauxite to produce alumina by Bayer process. However, t...

AI Technical Summary

Problems solved by technology

However, the flotation method is not only costly, but the total recovery rate of alumina is low, and the introduction of organic matter into the alumina production process has brought many negative effects, and the tailings are also difficult to stockpile and utilize due to high moisture content.

In addition to desiliconization by flotation, bauxite can also be desiliconized by chemical desiliconization. The main principle of the process is to roast the bauxite first to convert the silicon minerals such as kaolinite into mullite and amorphous SiO2. Then it is leached with caustic lye, but due to its complicated process flow and high energy consumption, it has not yet formed a technology that can be applied industrially.