Decomposition and filtration method during alumina production process

Abstract

A decomposition and filtration method during the alumina production process belongs to the technical field of alumina production. A vertical disc filter, a vacuum liquid receiving tank and a gas-liquid separation device are arranged over a first decomposer of a decomposer system. The method provided by the invention comprises the following steps of: allowing aluminium hydroxide slurry in a last decomposer of the decomposer system to enter into the vertical disc filter, pumping and back-flushing the vertical disc filter, separating a filter cake and decomposing a mother liquor, allowing a cold seminal fluid to enter into the vertical disc filter to dilute the unloaded filter cake, discharging the diluted filter cake into the first decomposer of the decomposer system by the utilization of potential difference, and allowing an overflow of the vertical disc filter to enter into the last decomposer. By the utilization of potential difference, the diluted filter cake is directly conveyed into the first decomposer from the vertical disc filter, thus simplifying the flow and saving land occupation, equipment investment and power consumption.

Description

technical field [0001] The invention belongs to the technical field of alumina production, in particular to a decomposition and filtration method in the alumina production process. Background technique [0002] The decomposition area configuration of a traditional alumina plant is usually a decomposition tank system plus a seed filter plant. The output of the decomposition tank flows to the seed filter plant through the overflow pipe in the middle and upper part of the final decomposition tank to separate the mother liquor and seeds. The filtered seeds After the semen is diluted, it falls into the seed crystal tank under the seed filtration plant, and after stirring and mixing, the seed crystal pump is sent to the first decomposition tank; the overflow of the filter enters the overflow tank in the plant, and is sent to the first tank by the overflow pump. Decompose the end tank of the workshop; although this layout method is adopted by most domestic alumina plants, it also h...

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Problems solved by technology

[0002] The decomposition area configuration of a traditional alumina plant is usually a decomposition tank system plus a seed filter plant. The output of the decomposition tank flows to the seed filter plant through the overflow pipe in the middle and upper part of the final decomposition tank to separate the mother liquor and seeds. The filtered seeds After the semen is diluted, it falls into the seed crystal tank under the seed filtration plant, and after stirring and mixing, the seed crystal pump is sent to the first decomposition tank; the overflow of the filter enters the overflow tank in the plant, and is sent to the first tank by the overflow pump. Decompose the end tank of the workshop; although this layout method is adopted by most domestic alumina plants, it also has the following disadvantages: (1) It occupies a large area and needs to build a separate seed filtration plant, and the general plan requires a special location for configuration; (2) The increase in cost investment requires not only the production of a larger plant frame, but also the configuration of corresponding auxiliary equipment such as: seed tanks, seed pumps, overflow tanks, overflow pumps, etc., and the cost of civil engineering and equipment increases; (3 ) The operating cost increases, and the seed tank, seed pump, overflow tank, and overflow pump increase the power load consumption and equipment maintenance work; The conversion from the pump to the first decomposition tank, and from the overflow tank to the overflow pump, and from the overflow pump to the final decomposition tank increases the workload of the on-site operators and reduces the work efficiency; (5) It is not good for the process itself, because from the general layout In general, there is a certain distance between the decomposition and seed filtration workshops. Therefore, most of the takeover of the decomposition and seed filtration workshops needs to be connected with the outdoor pipe network, and the investment of the outdoor pipe network in pipes and pipe racks will increase accordingly.

Sometimes due to configuration problems, the pipeline runs far away, and the slurry pipeline will be blocked in the middle

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