Reduction of iron ore grinding stages through the use of fine screening in a closed cycle

Abstract

The possibility of application of a two-stage grinding scheme with the use of fine screening in a closed cycle of the second stage instead of a three-stage scheme with hydrocyclones was studied. Under laboratory conditions, an assessment of the effect of the sieve openings size of the screens used in the second grinding stage on the performance of the production of titanomagnetite concentrate for agglomeration was made. The sizes of sieves are considered: 0.63; 0.315; 0.16 and 0.1 mm. Reduction of the sieve opening size from 0.63 to 0.1 mm leads to an increase in the iron content in the concentrate from 56.32 to 62.71 %. At the same time, the yield of the concentrate decreases from 19.75 to 16.65 % and the extraction of iron into the concentrate from 71.07 to 66.72 %. It is shown that the concentrate for agglomeration with iron content of 61% can be obtained using two stages of grinding. The size of the sieve openings of the screens of the second stage should not exceed 0.2 mm. The results obtained in laboratory and industrial conditions, when using 0.15 and 0.1 mm sieves, do not fundamentally differ. Before industrial testing of the new enrichment scheme, it is necessary to perform experimental simulation of the schemes in the laboratory. The two-stage grinding scheme using fine screening in the second stage can be used in the enrichment of titanomagnetite ore. This will reduce the cost of grinding ore. Reduction of the grinding stages leads to an increase in the size of the concentrate, so the scheme is applicable for the production of concentrate for agglomeration.