Experimental Study on Optimization of Pre-selection Process of a Mixed Iron Ore Abroad
The total iron grade of a foreign mixed iron ore is 36.59%,and the iron content in magnetic iron is 26.85%.In order to efficiently recover the iron resources and reduce the amount of grinding,the pre-selection process test was carried out.The results show that the concentrate with yield of 88.08%and iron grade of 38.63%can be obtained by dry magnetic separationdiscarding tailing after crushing the raw ore to-20 mm,and the concentrate grade is only increased by 2.35 percentage points.The rough concentrate was ground to-3 mm by high-pressure roller mill,and the concentrate with yield of 63.02%and iron grade of 50.37%was obtained by one roughing one cleaning lowintensity magnetic separation,and the concentrate grade was increased by 11.86 percentage points.The high-pressure roller mill product-3 mm sample was subjected to lowintensity magnetic separation.The yield of-0.15 mm fraction in the lowintensity magnetic concentrate was 39.48%,and the iron grade was as high as 64.75%.Screening dehydration can be directly used as iron concentrate.The high-pressure roller mill product-3 mm sample high-intensity magnetic con-centrate was screened,and the product under the sieve was gravity separated by chute to obtain the concen-trate with operating yield of 32.10%and iron grade of 62.60%.Based on the goal of more crushing and less grinding,energy saving and emission reduction,it is recommended that the pre-concentration principle pro-cess of mixed iron ore is the pre-concentration process of raw ore conventional crushing-high pressure roller mill(-3 mm)-wet magnetic separation + SLon high gradient highintensity magnetic separation coarse parti-cle pre-concentration and tailings discarding-screening dehydration-screening onsize coarse concentrate in-to grinding-screening undersize pulp through lowintensity magnetic separation + gravity separationobtaining concentrate directly.
mixed iron orepre-selection and discardingmetal recovery ratemore crushing and less grinding
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