A stripping process and desulfurization method for producing alumina by using high-sulfur bauxite

Abstract

The invention discloses a dissolution process and desulfurization method for producing aluminum oxide by using high sulfur bauxite. The method is characterized in that the sulfur content of a circulating mother liquor is controlled under the suitable conditions, bayer dissolution is performed on the high sulfur bauxite by adopting a 'low temperature and high alkali' process, sulfur in ores transferring into a sodium aluminate solution is reduced while obtaining a relatively high aluminum oxide dissolution rate, a part of sulfur is consumed through self-balancing of a system, and appropriate desulphurization is performed on a decomposition mother liquor or causticized liquid by using barium salt when the sulfur content in the system is accumulated to a certain extent so as to keep the virtuous circulation of the whole production process. The dissolution process and desulfurization method, disclosed by the invention, do not change the existing bayer-method aluminum oxide production process, are low in cost and simple and convenient in operation, and provide a good foundation for the industrialization of the high sulfur bauxite; desulfurization slag can be used as a raw material for preparing a barium salt desulfurizer so as to further reduce the production cost.

Description

technical field [0001] The invention relates to the technical field of producing alumina by the Bayer method, in particular to a dissolution process and a desulfurization method for producing alumina by using high-sulfur bauxite. Background technique [0002] At present, my country's demand for bauxite has increased significantly, and high-grade bauxite reserves are decreasing day by day. However, my country's high-sulfur bauxite reserves are abundant, accounting for about 11% of the total bauxite resources, mainly distributed in Chongqing Cave. Bay, Qingzhen and Wuchuan in Guizhou, Dahua in Guangxi, Zibo in Shandong, Caoyao Coal Mine and Yushan in Henan, and Banmao in Yunnan. Most of these high-sulfur ores have relatively high alumina grades, with an aluminum-silicon ratio of about 7.0. Accelerating the development and perfecting the industrial application of high-sulfur bauxite is an urgent problem to be solved at present. [0003] However, there are still many problems i...

AI Technical Summary

Problems solved by technology

Existing studies have shown that the use of beneficiation and sintering to remove sulfur, although the process is simple, but the recovery rate of the beneficiation method is low, the cost of wastewater treatment is increased, and the filtration and dehydration of the concentrate are difficult, so that the water needs to be removed in the evaporation section, which increases energy consumption. , the organic chemicals adsorbed on the surface of the concentrate are brought into the system, which deteriorates the production index; while the sintering method has a large amount of ore to process, and the ore needs to go through a fine grinding process, resulting in increased energy consumption and cost, and the release of SO 2 The gas will be vented into the atmosphere (increasing the cost of secondary treatment)

From the perspective of production process, economic benefits and production environment, it has its limitations

However, when high-sulfur bauxite is produced by Bayer process, the amount of sulfur in the ore is usually transferred into the solution is relatively large, and sulfides of various valences affect the species separation process and the effect of evaporation and salt removal. Some studies have shown that if you want to Reducing the dissolution rate of sulfur must be at the expense of the dissolution rate of alumina, which virtually increases the production cost