System and process for decomposing crystal seed of aluminum hydroxide

Abstract

The invention relates to a system and a process for decomposing a crystal seed of aluminum hydroxide during the production of aluminum oxide. The crystal seed decomposing system comprises a decomposing tank, a vertical disc filtering machine, a spiral slurry-decomposing machine and a sliding chute, wherein the vertical disc filtering machine is arranged at a position close to the first tank of the decomposing tank and can filter feed slurry from the last tank of the decomposing tank; a filter cake is mixed with supersaturated solution of sodium aluminate to form the feed slurry of the crystal seed by using the spiral slurry-decomposing machine arranged between the vertical disc filtering machine and the first tank of the decomposing tank; the feed slurry of the crystal seed enters the first tank of the decomposing tank by the sliding chute and then orderly enters all decomposing tanks till the last tank of the decomposing tank for step-to-step crystallation and growth; and the feed slurry in the last tank of the decomposing tank is pumped in the vertical disc filtering machine by a feeding pump of the vertical disc filtering machine and filtered. By using the process, a crystal seed tank and a stirring step thereof, a crystal seed pump and pipes thereof, an overflow tank and a stirring step thereof and an overflow pump are saved, the problem of the scab of the crystal seed is solved, and equipment cost and power consumption are reduced.

Description

technical field [0001] The invention relates to an alumina production process, in particular to an aluminum hydroxide seed decomposition process and system. Background technique [0002] In the traditional process of producing alumina by the Bayer process, the decomposition of sodium aluminate solution is one of the important processes, generally known as the seed crystal decomposition process, which is to add a large number of crystal seeds to the decomposition tank to induce crystallization and crystallization of aluminum hydroxide crystals. Grow up to decompose the supersaturated sodium aluminate solution. The grown aluminum hydroxide product is separated by a classifier and sent to the sintering process to prepare alumina; the slurry at the end of the decomposition tank is filtered, and the filter cake is used as a crystal seed. [0003] In the traditional seed crystal decomposition process, most of the process layout is to place the vertical disc filter near the end of...

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Problems solved by technology

[0006] In order to overcome the above-mentioned shortcomings, the present invention proposes a seed crystal decomposition process used in alumina production, which eliminates the input of seed crystal tanks, seed crystal pipelines, and small circulating pumps, and completely eradicates the scarring of the seed crystal tank and the The aging problem of pipeline flanges not only reduces the initial investment, but also achieves the purpose of energy saving and consumption reduction

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