Coal dressing magnetite powder magnetism strengthening method

Abstract

The invention relates to a coal dressing magnetite powder magnetism strengthening method, and solves the economic waste problem caused by technical loss in the prior art for the reason that fine-grained magnetite powder is poor in magnetism. The coal dressing magnetite powder magnetism strengthening method comprises the following steps: A. putting magnetite powder in a corundum crucible, then putting in a heating furnace, reducing the pressure until the air pressure in the heating furnace is 0.01-0.1MPa; B. heating the heating furnace to 300-700 DEG C, after 30-60min of heat preservation, stopping heating; C. naturally cooling the heating furnace in air, at the same time, applying a pulsed magnetic field with a frequency of 30-500Hz and a magnetic field strength of 5000-15000oe to the side face of the heating furnace until the heating furnace is cooled to room temperature; and D. taking the magnetite powder for packaging storage. By synergistic effect of heating and the pulsed magnetic field on processing of the coal dressing magnetite powder, the coal dressing magnetite powder material magnetism is strengthened, medium consumption in the coal dressing process can be reduced, and the coal dressing magnetite powder has the advantages of simple process, low strength and low cost.

Description

technical field [0001] The invention relates to a method for strengthening the magnetism of magnetic dense medium powder, in particular to a method for strengthening the magnetism of magnetite powder for coal preparation. Background technique [0002] At present, most countries attach great importance to coal washing, especially developed countries. At present, the average selected proportion of raw coal in the world is about 50%, and some countries even exceed 80%. Although some countries in Europe have closed almost all coal mines, there are still coal preparation plants used to process imported coal. [0003] The most commonly used coal preparation method is dense medium coal preparation. The medium powder in the dense medium coal preparation is used to increase the density of the liquid, and it can be repeatedly recovered and utilized by the magnetic separator in the process of coal preparation. [0004] However, the magnetic medium powder has a problem of medium cons...

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Problems solved by technology

[0006] In order to solve the problem of economical waste caused by technical loss due to the weak magnetism of the existing fine-grained magnetite powder, the present invention provides a method for strengthening the magnetism of magnetite powder for coal preparation

[0008] The selection of pressure, heating temperature and holding time, as well as the frequency and intensity of the pulsed magnetic field is obtained through a large number of repeated tests, which overcomes the problem of economic waste caused by the technical loss of the existing fine-grained magnetite powder.