High-pressure dissolution-out and evaporation combined energy-saving method in production of aluminium oxide

A high-pressure dissolution, medium-high pressure technology, applied in the direction of alumina/hydroxide, etc., can solve the problems of low utilization efficiency, waste of heat, high comprehensive energy consumption of alumina, etc., to reduce production energy consumption and cost, good economic benefits and Social benefits, the effect of improving technical and economic indicators

Inactive Publication Date: 2014-10-15
SHENYANG ALUMINIUM MAGNESIUM INSTITUTE
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  • Application Information

AI Technical Summary

Problems solved by technology

98% of the domestic bauxite is monohydraulic bauxite, which requires high-pressure dissolution. Under the current technology and equipment level, the secondary steam generated by high-pressure dissolution cannot be fully utilized, and the secondary steam that cannot be absorbed is produced by the final stage. It is directly discharged into the atmosphere ...

Method used

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  • High-pressure dissolution-out and evaporation combined energy-saving method in production of aluminium oxide

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Effect test

Embodiment 1

[0013] The domestic diaspore-type bauxite is processed by the high-temperature Bayer method, with a high-pressure dissolution temperature of 260°C and 280°C new steam heating. The new steam condensate generated by the new steam is flashed to 0.6MPa at the first stage, and the flash steam is sent to the mother liquor evaporation process through pipelines to partially replace the evaporated new steam. Save 16.3kg standard coal per ton of alumina.

Embodiment 2

[0015] The domestic diaspore-type bauxite is processed by the high-temperature Bayer method, with a high-pressure dissolution temperature of 280°C and 300°C new steam heating. The new steam condensate generated by the new steam is flashed to 0.4MPa in two stages, and the flash steam is sent to the mother liquor evaporation process through pipelines to partially replace the evaporated new steam. The 0.4MPa flash steam generated from the 6th stage pulp flash evaporation is sent to the mother liquor evaporation process through the pipeline to replace the new steam. Save 20.7kg standard coal per ton of alumina.

Embodiment 3

[0017] The domestic diaspore-type bauxite is treated by the high-temperature Bayer method, the high-pressure dissolution temperature is 280°C, and the molten salt is heated at 320°C. The 1MPa flash steam generated from the fifth-stage pulp flash evaporation is sent to the mother liquor evaporation process through the pipeline to replace the new steam for evaporation. Save 15.9kg standard coal per ton of alumina.

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Abstract

The invention relates to an energy-saving method in production of aluminium oxide and especially relates to a high-pressure dissolution-out and evaporation combined energy-saving method in production of the aluminium oxide. The method includes following steps: heating dissolved-out raw ore pulp with new steam employed in a high-pressure dissolution-out process to obtain new steam condensed water; performing a flash process to the new steam condensed water to form a flash steam under a pressure of 0.4-0.6 MPa; sending the flash steam through pipelines to a mother liquid evaporation process for partially replacing new steam; carrying out a multistage flash process to the dissolved-out raw ore pulp after the high-pressure dissolution-out process, wherein a flash steam, under a pressure of 0.4-1.0 MPa, is generated in first-stage flash from the fourth stage to the sixth stage in the multistage flash process with from the ninth stage to the eleventh stage being pre-heated; and sending the flash steam to the mother liquid evaporation process through pipelines for partially replacing the new steam. The method is characterized by employing a new high-pressure dissolution-out and evaporation combined energy-saving technology so that thermal energy in a system can be utilized better, thereby achieving a purpose of saving energy.

Description

technical field [0001] The invention relates to an energy-saving method for alumina production, in particular to an energy-saving method for combining high-pressure dissolution and evaporation in alumina production. Background technique [0002] In the process of producing alumina by Bayer process (or part of the Bayer process in the combined process), pressure cooking and dissolution and evaporation of mother liquor are the main energy-consuming (steam-consuming) processes. 98% of domestic bauxite is monohydraulic bauxite, which requires high-pressure dissolution. Under the current technology and equipment level, the secondary steam generated by high-pressure dissolution cannot be fully utilized, and the secondary steam that cannot be absorbed is produced by the final stage. It is directly discharged into the atmosphere from the evaporation or dilution tank, resulting in waste of heat, so that the comprehensive energy consumption of alumina produced by Bayer process in my c...

Claims

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Application Information

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IPC IPC(8): C01F7/02
Inventor 李来时刘涛涛王剑周凤禄唐时健
Owner SHENYANG ALUMINIUM MAGNESIUM INSTITUTE
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