Research On Processing Technology Of YanQianshan Iron Ore

The YanQianshan iron ore for over40years is the one of magnetite resource base in Ansteel. However, the iron ore from Yan Qianshan is difficult to be separated due to complexity of mineral compositions、complex structure and low grade of raw ore.1the feasibility test of YanQianshan iron ore commissioned by Anstee was conducted in the paper.The analysis, such as SQR, chemical composition analysis, XRD, iron chemical phase analysis and rock-mineral determination, of the iron ore and the study of mineral processing were investigated.The analysis of process mineralogy showed that magnetite and hematite with fine grained nonuniform distribution were the main iron bearing mineral in five kinds of YanQianshan iron ore. Both magnetite and hematite as fine grains were scattered in the gangue and some gangue minerals were locked in magnetite and hematite, which showed that both iron-bearing minerals and gangue were closely associated each other. Not only that, both magnetite and hematite were closely associated too. Association of the above three components have significant impact on liberation. Thus, on the view of process mineralogy, these five iron ores were refractory ore.Experiments of coarse and fine classification-gravity concentration, stage grinding-low intensity magnetic separation-high intensity magnetic separation-stage flotation and stage grinding-low intensity magnetic separation-high intensity magnetic separation-reverse flotation were carried out to separate mixed ores from YanQianshan. Therefore, flowsheets of stage grinding-low intensity magnetic separation-high intensity magnetic separation-stage flotation were determined by systematic mineral processing tests and iron concentrate product with the grade of60.50%at the recovery of56.79%was obtained.Flotation concentrate was roasted and a great change in iron content was observed before and after roasting experiments. It was inferred that there existed minerals of high ignition loss such as siderite in the iron concentrate, which resulted in lower iron grade. It was shown under optical microscope that many monomer gangue particles and locked particles of iron and gangue minerals existed in the concentrate. The former is in that fine siderite particles were adsorbed on the both surfaces of iron and gangue minerals, causing little difference in surface properties between them and low grade of iron concentrate. And, the later is due to fine dissemination between iron and gangue minerals. So, in order to improve the iron grade, finely grinding is necessary to increase liberation of iron mineral. But overgrinding lead to the dramatic decrease in recovery and bring a lot of problems in subsequent operations.The anticipated object was obtained in this paper, which is instructive in effective utilization of refractory ore from YanQianshan.