Material return process and device for alumina roasting furnace

Abstract

The invention discloses a material return process for an alumina roasting furnace. Aluminum hydroxide captured by a main dust remover and discharged along with waste gas after being dried is preheatedand then separated, fine particles are discharged along with the waste gas and collected by a secondary dust remover, and coarse particles are discharged into the roasting furnace to be roasted. A device comprises the main dust remover serially connected to an exhaust port of a preheating cyclone PO1 for aluminum hydroxide raw materials in alumina roasting equipment; and a charge port of a separator PO5 is connected with a discharge port in the bottom of the main dust remover through a material pipe; the exhaust port is connected with the secondary dust remover; and the discharge port is connected with the roasting furnace PO4. The collected mixture of about 15% of alumina and aluminum hydroxide is subjected to conveying, preheating, suspension and mixed dehydration, cyclone dust collection, and cloth-bag dust collection, and then discharged into the main dust remover through a fan, wherein large particles subjected to the cyclone dust collection are fed into the lower middle part ofthe roasting furnace PO4 to continue to be roasted; and the fine particles are collected and discharged through the cloth-bag dust collection for export sales for other alumina products or other applications.

Description

technical field [0001] The invention relates to a material-returning process and device, in particular to a material-returning process and device for an alumina roasting furnace. Background technique [0002] Alumina is the main raw material for electrolytic aluminum production. [0003] According to the characteristics of ore in my country, the production process of alumina in my country mainly adopts the Bayer method, sintering method and mixed method; in the Bayer method, the roasting process is an indispensable process for alumina production, and it is the main process of the entire alumina production process. The last process of the production process, the main task of this production process is to calcinate the aluminum hydroxide substance with attached water from the decomposition or flat plate at high temperature in the roaster to remove the attached water and crystallization water, so as to form the physical and chemical properties consistent with electrolysis alumin...

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Problems solved by technology

[0006] It is precisely because the return material (15%) of alumina collected by the electrostatic precipitator is sent to CO2, so that the entire roasting production process technology has the following disadvantages: (1), the overall system of the entire multi-stage cyclone cooler The temperature drop is unstable; (2), the alumina (85%) that enters the roaster through PO2 is roasted, the energy consumption is high, and the output is low; (3), the ignition loss increases

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