Method for producing sandy alumina through decomposing seeds in low concentration

Abstract

A process for preparing sandy alumina by decomposing low-concentration seed includes such steps as mixing the refined liquid from settling workshop with the fine seeds from plate-and-frame filter press, stage-one decomposing, stage-two decomposing, classifying by hydraulic cyclone bed, filtering part of bottom stream to obtain finished product, filtering the rest to obtain seeds, filtering overflow liquid to obtain fine seeds, adding fine seeds to the stage-one decomposing reactor, adding coarse seeds to the stage-two decomposing reactor, and heat exchange between mother liquid and refined liquid.

Description

Technical field:

[0001] The invention relates to a method for producing sandy alumina by decomposing low-concentration seeds. Background technique:

[0002] Seed decomposition is one of the important processes in the production process of Bayer process alumina. Its task is to precipitate aluminum hydroxide from the supersaturated sodium aluminate solution by controlling the seed separation conditions, and the aluminum hydroxide obtained from the decomposition can be used for subsequent Process processing.

[0003] Due to the different bauxite processed by the alumina plant, the dissolution conditions are different, and the composition of the obtained sodium aluminate solution is also different. Generally speaking, domestic alumina plants that process diaspore and gibbsite, after dissolution, The concentration of alkali and alumina in the semen obtained by leaf filtration is relatively high, generally Na 2 o K Concentration 145~172g / l, Al 2 o 3 The concentration is 160-1...

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