Process for producing iron ore concentrate by graded dry grinding and dry separation of low-grade magnetite

Abstract

The invention discloses a process for producing iron ore concentrate by graded dry grinding and dry separation of low-grade magnetite, and aims to solve the problems of long process flow, low concentrate grade and low recovery rate of a traditional iron ore dry fine separation process. The process comprises the steps that after low-grade iron ore is crushed by using a jaw crusher and subjected tomagnetic separation by using a roller magnetic separator, a part of large-particle waste rock is removed at first, then, the low-grade iron ore is subjected to fine crushing by adopting a crushing roller press and subjected to dry separation by adopting a spiral magnetic separator, and a part of small-particle waste rock is thrown off; and the obtained preseparated ore is subjected to coarse grinding by adopting a dry vertical grinding machine, dry separation by adopting the spiral magnetic separator, and dry separation by adopting a wind-magnetic combined separator, then a part of fine-graintailings is removed, a part of iron ore concentrate is recycled, residual materials is subjected to fine grinding by adopting the dry vertical grinding machine and magnetic separation by adopting thewind-magnetic combined separator so as to carry out iron mineral recovery. According to the process, excessive crushing and less grinding, multi-stage ore grinding and multi-stage dry separation are adopted, and the procedure energy consumption in the grinding and separation processes is reduced while the iron ore concentrate grade and the beneficiation metal recovery rate are increased.

Description

technical field [0001] The invention belongs to the technical field of beneficiation engineering, and in particular relates to a process for producing iron ore concentrate by grading and dry-grinding dry-separation of low-grade magnetite. Background technique [0002] Magnetic separation of iron ore is a widely used beneficiation method. For specific susceptibility χ>3×10 -3 cm 3 / g of iron ore can be recovered by weak magnetic separation equipment (that is, weak magnetic separation process) with a magnetic field strength of 120-279KA / m (1500-3500 Oe). Common resources containing strong magnetic substances include natural magnetite, maghemite (γ-Fe 2 o 3 ), titanium magnetite, pyrrhotite, zinc iron spinel [(Zn, Mn) Fe 2 o 4 ] and roasted magnetite (including power plant iron-containing fly ash), steelmaking converter smelting slag and other iron materials. [0003] The iron ore weak magnetic separation process is divided into wet weak magnetic separation and dry we...

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Problems solved by technology

For arid and water-scarce areas, this disadvantage is particularly prominent;

[0007] (2) The iron ore wet process will produce secondary pollution and affect the quality of groundwater; the tailings are stored in the warehouse, and the daily operation must prevent water leakage and dam breakage. In addition to increasing costs, there are also safety and environmental risks; tailings ponds Occupying a large area, it is difficult to realize reclamation after the storage is closed;

[0008] (3) The water conten

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