Process for efficiently utilizing secondary steam in dissolution procedure

Abstract

The invention relates to a process for efficiently utilizing secondary steam in a dissolution procedure, which comprises the following steps that a first-stage autoclave dissolution double-pipe preheater is omitted, secondary steam of a corresponding reciprocal second-stage self-evaporator is fed into a pre-desiliconization procedure, and pre-desiliconized feeds in a pre-desiliconized double-pipe heat exchanger are heated to a desiliconization temperature; dissolution feeds are heated in late several stages of autoclave dissolution double-pipe preheaters through secondary steam of the previous several stages of self-evaporators, and heated to a dissolution temperature in an autoclave dissolution new steam heating jacket through new steam; and the dissolution feeds stop in a digester, and then enter the previous several stages of self-evaporators, the reciprocal second-stage self-evaporator and the tail-stage self-evaporator to carry out self-evaporative cooling. The process disclosed by the invention has the advantages and effects that because the slurry temperature of the pre-desiliconized feeds is low, the pre-desiliconized feeds can be heated by using secondary steam with low dissolution parameters, thereby reducing the heat exchange area required by the dissolution process, and also greatly reducing the pressure of a dissolution feed pump.

Description

technical field [0001] The invention relates to a process for efficiently utilizing the secondary steam of the dissolution process. By changing the use of the low-parameter secondary steam of the dissolution process in the production of alumina, the purpose of efficiently utilizing the secondary steam of the dissolution process is achieved, which belongs to the production of alumina technology field. Background technique [0002] In the production of Bayer alumina, new steam is mainly used in the processes of pre-desilication, pressure cooking and dissolution, separation and washing of red mud, mother liquor evaporation, aluminum hydroxide filtration, etc. Among them, the major steam users are mainly pre-desilication, pressure cooking and dissolution and The mother liquor is evaporated, and the steam consumed by these three processes accounts for 80% of the total steam consumption. In the production of Bayer process alumina, the process of flashing low-parameter secondary s...

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Problems solved by technology

[0004] For the utilization of low-parameter secondary steam, it is mainly heat exchange. However, due to the low temperature of this part of secondary steam, the required heat exchange area is relatively large. In addition, the applicable working conditions are relatively limited. Must be lower temperature material heating

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