Method for full resource utilization of red mud

Abstract

The invention relates to a method for full resource utilization of red mud. The method for full resource utilization of the red mud specifically comprises the following steps of 1) washing the red mudto recover sodium hydroxide; 2) stirring and leaching out red mud washing residues in a concentrated acid rotary kiln; 3) using the leaching residues obtained in the step 2) for producing sodium silicate and building ceramsite; 4) adjusting the pH value of a leaching solution by using liquid ammonia or ammonia water to precipitate aluminum ammonium sulfate; 5), precipitating an aluminum ammoniumsulfate solution to produce iron oxide red; 6) enriching scandium, vanadium, titanium and gallium through ion exchange; and 7) carrying out MVR evaporative crystallization of ammonium sulfate. The method for full resource utilization of the red mud has the advantages that the pigment-grade iron oxide red with bright color can be obtained without calcining the produced iron oxide red, large-particle smelting-grade aluminum oxide and artificial cryolite can be produced, industrial-grade pure oxides of titanium, scandium, vanadium, gallium, rhenium and rare earth can be produced, full resource recovery of the red mud can be truly realized, the process is simple, the cost is low, and large-scale production is easy.

Description

technical field [0001] The invention relates to a method for recovering high-purity alumina, iron oxide, scandium, vanadium, titanium, gallium and rare earth elements from red mud. Background technique [0002] Red mud is a very fine-grained strong alkaline solid waste produced during the production of alumina from bauxite. For every ton of alumina produced, about 0.8-1.5 tons of red mud are produced. my country is a big producer of alumina. In 2009, it produced 23.78 million tons of alumina, accounting for about 30% of the world's total output, and produced nearly 30 million tons of red mud. At present, the comprehensive utilization rate of red mud in my country is only 4%, and the cumulative stockpiles have reached 200 million tons. With the annual increase of alumina production in my country and the gradual decrease of bauxite grade, the annual production of red mud will continue to increase. It is estimated that by 2015, the cumulative stockpiling of red mud will reach ...

AI Technical Summary

Problems solved by technology

[0003] The main problems in the current comprehensive utilization of red mud: (1) Lack of key technologies for large-scale consumption of red mud and industrial competitiveness

Red mud has the characteristics of strong alkalinity, large specific surface area, and interwrapping and intercalation of various components, making it difficult for its comprehensive utilization to learn from some mature processes, technologies and equipment in other fields. Technical support system for large-scale promotion

(2) Lack of corresponding standards and low product market acceptance

Currently, some red mud comprehensive utilization products that have been developed lack the support of national standards or industry standards, such as red mud used as building materials, only by referring to the standards of other similar products, and the market acceptance is low, resulting in limited product applications and difficult to scale up. Scale promotion

(3) Lack of targeted support policies

In my country's current preferential fiscal and taxation policies, the difficulty of comprehensive utilization of red mud caused by strong alkalinity is far greater than that of other industrial waste residues. There is a lack of targeted support policies, and enterprises are not motivated to use red mud.

(4) The degree of attention to the comprehensive utilization of red mud needs to be improved

The environmental risks and safety hazards of red mud stockpiling are long-term and hidden, which leads to insufficient attention of enterprises and relevant departments

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