Method and system for producing sandy aluminum oxide through three-section seed decomposition

Abstract

The invention relates to a method for producing sandy aluminum oxide through three-section seed decomposition in a process of producing aluminum oxide with a Bayer process or in a Bayer process part of a combined process. The method for producing the sandy aluminum oxide through three-section seed decomposition comprises the steps of: mixing fine fluid with seeds; feeding into a first-section decomposition groove; discharging; performing first-stage cooling; feeding into a second-section decomposition groove; forming a necessary gravity fractionation layer in the decomposition groove by controlling proper stirring intensity; and drawing out coarse particles from the bottom of the groove and taking the coarse particles as aluminum hydroxide products; performing second-stage cooling on overflow containing fine particles at the upper part; feeding into a third-section decomposition groove; separating the underflow; performing seed filtering and washing processes; mixing the filtered seeds with the fine fluid; returning to the first-section decomposition groove; and performing an oxalate removing process on a seed washing solution after the seeds are washed. According to the method and system provided by the invention, by adoption of the three-section decomposition technology, the positions of the products to be output and the seeds are respectively arranged in the first-section and third-section decomposition grooves, so that the aims of obtaining high-quality aluminum hydroxide product, realizing high yield and flexible process control and facilitating the removal of oxalate are achieved.

Description

technical field [0001] The invention relates to a method and system for producing sandy alumina by using three-stage seed decomposition in the alumina production of the Bayer process or the Bayer process of the combined process, and belongs to the technical field of alumina production. Background technique [0002] At present, there are two popular decomposition technologies in our country. One is a one-stage decomposition technology represented by the technology of Bishine Aluminum Company, that is, the semen and seeds enter the first decomposition tank together, and after staying for a long enough time, the decomposition tank discharges After one classification, the underflow is sent to the flat plate filtration process as the finished product of aluminum hydroxide, and the overflow is filtered by the filter and returned to the first decomposition tank as seeds. The core of its technology is mainly grown by crystallization. Seed ratio, one-stage grading, one-stage seeding ...

AI Technical Summary

Problems solved by technology

The crystallization strength of alumina produced by this method is relatively good, but the decomposition process is long, both stages adopt full-flow classification, the processing capacity is quite large, the investment cost of equipment is high, and the operating cost is also high

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