Method for magnetic separation of iron ore concentrate in red mud slurry in alumina production flow by Bayer process

Abstract

The invention relates to a method for magnetic separation of iron ore concentrate in red mud slurry in an alumina production flow by a Bayer process. The method comprises the steps of: leading the red mud slurry to flow under a secondary cleaning subsider of red mud in alumina production; removing slag by a slag screen, and removing scrap iron by a medium magnetic machine; entering a two cascade stage magnetic separator and carrying out magnetic separation; putting the magnetically extracted ore concentrate and the scrap iron removed by the medium magnetic machine into an ore concentrate slurry tank; filtering and dehydrating the ore concentrate slurry to obtain an iron ore concentrate filter cake; adding the slag removed by the slag screen, gangues obtained by magnetic separation and filtered and dehydrated filter liquor of the ore concentrate slurry in a gangue slurry tank; and returning the gangue slurry in a water mixing tank in the cleaning process of alumina production to enter a third red mud cleaning subsider. The invention has the advantages that the cleaning water of the red mud in the alumina production is used as magnetic separation process water without consuming additional fresh water. The invention has the characteristics of simple process and low cost, and is especially suitable for processing ferric red mud in the production of alumina.

Description

technical field [0001] The invention belongs to the technical field of red mud treatment technology for alumina production, and specifically relates to a process method for magnetically separating iron concentrate directly from red mud slurry, which is a material in a high-temperature Bayer process alumina production process of diaspore. Background technique [0002] In the production of diaspore Bayer process alumina, bauxite is mixed with lime and circulating lye to make qualified pulp and then dissolved. Under the action of high temperature and high pressure, the alumina in the ore enters the solution, and its insoluble matter is red mud. After the dissolution, the ore pulp is diluted and settled for solid-liquid separation, and the bottom flow red mud slurry produced is reverse washed three times, filtered to recover the attached alkali, and then discharged. The production of 1 ton of alumina will produce 1.2 to 1.5 tons of red mud. At present, a large amount of red mud...

AI Technical Summary

Problems solved by technology

At present, a lot of work has been done on the research of recycling iron in red mud at home and abroad. The main methods are magnetic separation, flotation, re-election and their combined processes, and the results are not ideal.

The recovery rate of iron can be greatly improved by mixing red mud and reducing agent, reducing roasting, and then magnetic separation, but the production cost is high, the process is complicated, and the industrial applicability is not strong

[0005] The invention patent "Method for Separating Iron Ore from Red Mud", patent number 200410023997.9, is mainly aimed at the red mud produced by the Bayer sintering combined alumina production method. The properties of the red mud produced by different ores and different alumina production methods are different. There is a big difference between the effect of iron selection and the production cost. This method is not very applicable to the production of red mud from diaspore high-temperature Bayer process alumina, and the process of the method is relatively complicated, and there is a problem of high production cost.

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