Dry-grinding and dry-separation method of magnetite

Abstract

The invention discloses a dry-grinding and dry-separation method of magnetite, which comprises the following steps of: feeding the crude ore of magnetite into a crusher for coarse crushing, and then feeding the crushed magnetite into a vibrating sieve for sieving; controlling the sieve meshes within a range of 35-75 mm; feeding the oversize product to the crusher for intermediate crushing and then feeding the crushed oversize product into a high-pressure roller mill along with the undersize product for fine crushing; breaking and grading the fine-crushed ore by a breaking-grading machine, thereby obtaining the products of three grain grades, i.e. coarse grains, fine grains and fine powder; returning the coarse-grain grade product to the high-pressure roller mill through an elevator, and feeding the fine-grain grade product to a dry type magnetic separator for magnetic separation and discarding tailings, wherein the magnetic field intensity is controlled within a range of 1200-3000 Gs; directly dryly stacking the discarded fine-grain grade tailings, and returning the fine-grain grade concentrate to the high-pressure roller mill through a belt conveyor and the elevator to form a closed loop; and feeding the fine-powder grade product into a cyclone magnetic separator, wherein the magnetic field intensity is controlled within a range of 600-1200 Gs, thereby obtaining concentrate or semi-concentrate. The dry-grinding and dry-separation method is low in power consumption, steel consumption and water consumption, and the tailings are easy to be disposed of.

Description

technical field [0001] The invention belongs to the technical field of mineral processing, and in particular relates to a magnetite dry grinding and dry separation method. Background technique [0002] At present, the magnetite beneficiation production process is a stage grinding-stage separation process, which mainly includes four stages: crushing, ore grinding, magnetic separation, and product treatment. After the raw ore is dry crushed by a gyratory crusher or a jaw crusher, the particle size is reduced to 300-350mm, and then after being dry crushed by a standard cone crusher, the particle size is reduced to 70-100mm. The material passes through a vibrating screen, and the material under the screen enters the powder The ore bin is temporarily stored, and the material on the screen enters the short-head cone crusher for fine crushing, and the product is returned to the vibrating screen by a belt conveyor, forming a closed circuit. The material under the screen in the powd...

AI Technical Summary

Problems solved by technology

The disadvantages of this method are: (1) The power consumption of the ball mill is high, and an average of 15-20 kilowatt-hours of electricity is required to process each ton of ore; (2) The steel consumption of the ball mill is high, and steel balls and liners are required to process each ton of ore 0.8-1.5kg, (3) During production, a large amount of water is required after the ball milling section, and an average of 3 tons of water is required to process 1 ton of raw ore. (4) Tailings need to be discharged into tailings ponds, which leads to high production costs and high tailings disposal costs. The security problem of the reservoir is serious. At present, the state no longer approves the construction of tailings reservoirs for small and medium-sized mines, so it has brought big problems to the production and operation of small and medium-sized mines.

The tailings ponds of large mines are also facing huge maintenance costs due to issues such as the expiration of the service life and environmental protection

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