Crystallization and concentration device used for extracting alumina from coal ash through acid leaching method

Abstract

The invention discloses a crystallization and concentration device used for extracting alumina from coal ash through an acid leaching method, which is capable of reducing the corrosion degree of secondary steam containing a strong acidic substrate on heat exchange tubes. The crystallization and concentration device comprises a shell, wherein heat exchange tubes, which are axially arranged along the shell are densely arranged in a radial section of the shell, two steam inlets are arranged on positions on the shell, which are located in the middles of the heat exchange tubes, a jacket used for preventing steam from the steam inlets to the shell is further arranged in the shell, and the positions on the heat exchange tubes, which are located on the two steam inlets, are located on the inner side of the jacket. The crystallization and concentration device has the advantages that after the jacket is arranged on the peripheries of the heat exchange tubes on the steam inlets, so that the secondary steam containing the strong acidic substrate from the steam inlets are directly sprayed on the jacket, the speed of the secondary steam is reduced, and the erosion of the secondary steam on the heat exchange tubes at the high speed can be avoided, thus the service life of the heat exchange tubes is prolonged.

Description

technical field [0001] The invention relates to a crystallization concentration device for extracting alumina from fly ash by acid leaching. Background technique [0002] In the crystallization concentration process of extracting alumina from fly ash by acid leaching, in order to reduce production costs, secondary steam is often used to exchange heat with alumina solution. The heat exchanger life of a steam inlet is very low, because the high-speed secondary steam enters the heat exchanger from the steam inlet and directly impacts the heat exchange tube, and the strong acidic substances in the secondary steam are washed at high speed. The tube will accelerate corrosion, and the corroded heat exchange tube cannot withstand the scouring of the secondary steam. SUMMARY OF THE INVENTION [0003] The technical problem to be solved by the present invention is to provide a crystallization concentration device for extracting alumina from fly ash by acid leaching, which reduces th...

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Problems solved by technology

[0002] In the crystallization and concentration process of extracting alumina from fly ash by acid leaching, in order to reduce production costs, the secondary steam is often used to exchange heat with the alumina solution, but because the secondary steam contains strong acidic substances, only The service life of a heat exchanger with a steam inlet is very low. The reason is that the high-speed secondary steam enters the heat exchanger from the steam inlet and directly impacts the heat exchange tubes. The corrosion of the tube will be accelerated, and the corroded heat exchange tube will not be able to withstand the erosion of the secondary steam

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