Method for producing aluminum oxide by means of granulating and sintering of low-grade bauxite

Abstract

The invention provides a method for producing aluminum oxide by means of granulating and sintering of low-grade bauxite.The method comprises the following steps that sodium carbonate, coke powder and alkali liquor are added to bauxite and limestone for blending, all the materials are added into a blender mixer for granulation, the finished granule products are sintered on a sintering machine, water or correction liquor is added to pulverized clinker for dissolution, obtained slag is reversely washed 5-7 times with water, and washing liquor serves as the correction liquor; a solution and sodium aluminate crystals are mixed and dissolved, desilicication is conducted, aluminum hydroxide crystal seeds are added for seed precipitation decomposition, and a seed precipitation mother solution is subjected to evaporation and salt elimination in two steps.According to the method, for the defect that low-grade bauxite is difficult to refine, the sintering technology of the smelting field is combined and utilized, the whole seed precipitation technology is provided, the technological processes of a technological process is shortened by one third or above, the seed precipitation decomposition rate is comprehensively calculated and increased to 90% or above, the total recovery rate of aluminum oxide reaches 90% or above, the operation difficulty is reduced, the equipment and personnel investment is reduced, and the energy consumption is reduced.

Description

technical field [0001] The invention belongs to the field of smelting, and in particular relates to a method for smelting bauxite by a pellet method. Background technique [0002] my country's bauxite resource grade (aluminum-silicon ratio) is low, and the production process of traditional sintering method not only makes the alumina production process complicated, but also increases the difficulty and production cost of alumina production. Therefore, at present, most enterprises in my country only use the Bayer process. For low-grade ores, if they are directly processed by the Bayer process, it will result in high alkali consumption, poor dissolution rate, and a sharp increase in cost, especially for bauxite in my country. It also contains silicon minerals such as illite, which cannot be removed by simple pre-desilication. These minerals are prone to reactions during the preheating process of the slurry, and sodium-silicon slag is precipitated on the heat exchange surface, wh...

AI Technical Summary

Problems solved by technology

At present, the only way to industrially process low-grade bauxite is traditional sintering technology. However, due to its complex process and high energy consumption, the production cost remains high. At present, the sintering production line in my country is basically in a state of shutdown.

[0004] Although according to the characteristics of my country's bauxite resources, some scientific research institutes and enterprises have developed technologies such as series and mixed methods to reduce alkali consumption and improve the recovery rate of alumina, but both methods require sintering. This has caused a series of problems such as complex and huge production system, increased infrastructure investment, high energy consumption, difficulty in control, and poor product quality. The economy is not good, so it is gradually reduced or stopped.

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