【摘要】 包头铁矿的选矿试验证明:利用细粒磁铁矿选择性团聚赤铁矿和借助水玻璃分散硅酸盐类脉石矿物,矿浆经多次脱泥即可获得满意的选铁指标。本文从微观角度分析了单个磁铁矿颗粒的磁场分布规律,指出当磁铁矿颗粒小于10微米时,其磁场梯度有显著提高,产生类似高梯度磁选机中“钢毛”介质所具有的“高梯度效应”,磁铁矿在自身团聚的过程中团聚了周围负电性低的赤铁矿;赤铁矿具有反铁磁结构,是其被微细粒磁铁矿团聚的内因。可以认为:包头铁矿选择性脱泥工艺的实质,是一种利用微细粒磁铁矿对赤铁矿产生磁力团聚的选择性脱泥过程。扫描电镜的图象分析进一步证实了上述论点。更多还原

【Abstract】 Prior to this paper’s work, it had been proved by many technique practices that Bao Tou Iron Ore’s selective desliming process was an effective new method for recovering very finely ground iron minerals (mainly hematite). With magnetite of about 20% weight in the crude ore, water glass as the key regulating reagent, pulp pH>9.5 and more than 97% passing 400 mesh, a satisfactory separation between iron minerals (hematite and magnetite) and gangue was achieved solely by desliming. The commercial test was completed in 1984, and a iron concentrate assayiug 61.87%Fe was yielded with recovery of 83.65% from the crude ore containing 32.03% Fe.This paper, through further experiments and theoretical analyses, presents a explanation for the mechanism of Bao Tou Iron Ore’s selective desliming process. That is: magnetite has some terrestrial magnetism, a magnetite particle forms a magnetic field in the out space around itself and shows high gradient effect when their particle size are reduced to minus 10 microns. High gradient effect makes it easy for the magnetite particles to act as a kind of magnetic medium to aggregate hematite in the same pulp. In principle, this aggregation process is something like that fine hematite particles in high gradient magnetic separators can be attracted to the "steel wool" with ease. Adding water glass and adjusting pH>9.5 is for the purpose of dispersing gangue particles.The magnetic aggregation mechanism, with high gradient effect as its core content, coincides with both the practices of Bao Tou Iron Ore’s selective desliming process and the experiment results obtained in this paper, and is confirmed by some specially designed experiment.更多还原