Heating and thermal insulation exsolution method for aluminum oxide high-pressure exsolution section

Abstract

The invention discloses a heating and insulating method for the high pressure digestion workshop section of alumina. The invention is characterized in that mineral slurry is heated by steam level by level in an autoclave (1) with a heating tube bundle inside; heat insulation and dissolution of the mineral slurry is done in a heat insulation dwelling tank (2) without heating tube bundle; eighty percent to eighty five percent of the total amount of new steam needed is added to the autoclave (1) from the first level to the fifth level; disolution reaction is done in advance to ensure that the mineral slurry reaches disolution temperature in the autoclave (1) from the first level to the fifth level before entering the heat insulation dwelling tank (2). Compared with the prior art, the heatingand insulating method for the high pressure digestion workshop section of alumina has the advantages of more reasonable distribution of the new steam quantity, more effective rinsing of the autoclavewith serious scab, good heat transfer effect, saving new steam more than twenty ton per hour, and increasing disolution rate of the mineral slurry by one percent.

Description

Technical field: [0001] The invention relates to a heating and heat preservation dissolution method of an alumina high-pressure dissolution section. Background technique: [0002] In alumina production, when diaspore is used as raw material to produce alumina, it is necessary to add aluminum ore to caustic soda to make slurry, and dissolve it at high temperature to make the alumina in the ore and caustic soda The reaction becomes sodium aluminate solution and enters the stripping pulp. During this process, steam is needed to heat the pulp step by step, so that the pulp reaches the dissolution temperature and then heats up and dissolves. The heating of the ore pulp is carried out in the autoclave with heating tube bundles inside. Usually, the heating area of ​​the autoclaves at all levels is the same. After being arranged into multiple rows with seamless steel pipes, they are vertically hung in the autoclave. The insulation dissolution was carried out in an autoclave without...

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Problems solved by technology

Using the above heating and heat preservation dissolution methods, two problems were found in the production process: (1) The temperature of the pulp in the heat preservation tank decreased, so that the dissolution reaction was not sufficient, thus affecting the dissolution rate of alumina in the pulp

Silicon and titanium scabs can be effectively cleaned by burning, but it is more difficult to clean red mud scabs with a hard surface and a soft middle. Since there are a large number of heating tube bundles in the autoclave, the space in the autoclave is already large. It is relatively narrow, and after the new steam is heated, the slurry of several stages of autoclave is thicker and occupies some space, which makes the work of cleaning the autoclave more difficult, the cleaning effect is not good, and the autoclave that is not cleaned is cleaned again. After it was put into operation, its heat transfer effect decreased significantly, and the consumption of stripping steam increased significantly.

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