Novel process for recycling aluminum oxide and iron oxide by dissolving out red mud at low temperature

Abstract

The invention relates to a novel process for recycling aluminum oxide and iron oxide by dissolving out red mud at low temperature. The novel process comprises the following steps: 1) preparing materials; 2) high-temperature dissolution; 3) cooling the slurry; 4) performing liquid-solid separation; the low-temperature dissolved red mud treatment method comprises the following steps of (1) red mud treatment, (2) red mud washing, (3) solid content adjustment, (7) roughing, (8) tailing concentration, (9) roughing concentrate concentration and desliming, (10) concentration, (11) concentrate concentration, (12) concentrate filter pressing, (13) concentration and desliming of concentrated tailings, (14) scavenging, (15) middling concentration and (16) middling filter pressing. The low-temperature dissolved red mud treatment method has the obvious advantages of being high in aluminum oxide recovery rate and iron oxide recovery rate, good in red mud sedimentation performance and large in red mud emission reduction.

Description

technical field [0001] The invention belongs to the technical field of alumina production, and in particular relates to a new process for recovering alumina and iron oxide by leaching red mud at low temperature. Background technique [0002] my country's bauxite resources are gradually exhausted, and the amount of bauxite imported by the domestic alumina industry is increasing day by day. Among the imported bauxite, the proportion of Guinea bauxite has exceeded 50%, and its annual import volume is still showing an upward trend; Guinea bauxite belongs to low-silicon gibbsite ore, and the silicon oxide content in the ore is basically 3 % or less, the alumina content is 45% to 48%, the crystal form is mainly gibbsite, the crystal water is about 23%, and there are more than 15% aluminum goethite and a small amount of boehmite; in the ore The content of iron oxide is 20%-23%, the content of organic matter is about 0.14%, and the water attached to the ore is about 10%. [0003] ...

AI Technical Summary

Problems solved by technology

[0005] (1) The relative dissolution rate of alumina in ore is generally low, and cannot exceed 90%

This is because the low-temperature dissolution temperature is too low to cause the dissolution reaction of aluminum goethite and boehmite in the ore, so the dissolution rate of alumina in the ore is low

[0006] (2) The sedimentation performance of the dissolved red mud is poor, and the number of washings is more, generally 6 washings are used

This is because the aluminum goethite in the ore has not undergone dissolution reaction, and the crystal form has not changed. It is still aluminum goethite in the red mud, which leads to poor red mud settling performance and large flocculant consumption.

[0007] (3) Aluminum goethite is contained in low-temperature leaching red mud, which has weak magnetism and low grade, so that the grade and iron recovery rate of iron concentrate obtained from red mud iron separation are low, and the grade of iron concentrate is about 45%-48 %, the recovery rate of iron is less than 33%

Images