Study On Increasing Of Iron Grade And Decreasing Silicon Content In Iron Concentrate Of Poor Magnetite In Fujian

As the growth of steel production and consumption, the demand of iron ore in our country is increasing. And domestic iron ore resources are plentiful but poor, lots of which are complex to concentrate. Therefore, research on separation for complex iron ores has an important practical significance on improving comprehensive utilization of domestic iron ore resources. The reasonable use of ultra-poor magnetite has also been put on the agenda. Based on the domestic and international recent research on magnetite, In order to resolve the technical difficulty that is complicated to dispose of the silica-fine particle in magnetite, we have taken on some research about it. And a good index is achieved in our experiment.Primary concentrate of the ultra-poor magnetite in Fujian Province as the object of the study, the primary concentrate iron grade of47.35%, the main metallic minerals are magnetite, also contains a small amount of hematite, limousine and iron silicate. The main gangue minerals are quartz. Gangue minerals and magnetite are closely linked, leading to being difficult to be separated.Firstly, after a series of gravity concentration and magnetic process tests on the primary concentrate, we find it is impossible to obtain qualified iron concentrate; secondly, we find screen size of0.074mm screen-throughs yield is much more than screen tailings by screen analysis of the primary concentrate. So it must be classified. The screen-throughs is magnetic processed and the screen tailing is processed as middles. After series of experiments on screen-throughs, a circuit is determined. When the screen size is0.056mm, a good index is achieved in our experiment. Wet feebleness magnetic separation machine is adopted in first concentration (magnetic intensity of0.06T), and magnetic separator column is adopted in concentration (pulp density of40%; current of2.0A; speed of rising water is180ml/s). In such conditions, iron concentrate grade of65.46%can be got. With the purpose of recovery, middles should be processed, the circuit is similar to the font, and iron concentrate grade of65.73%can be obtained. On this basis, a small closed circuit test is shown that it can get the final concentrate grade of65.30%, recovery of96.06%; and tailing grade of6.11%, recovery of3.94%.In order to get higher quality iron ore concentrate, the laboratory takes the magnetic concentrate as raw ore for flotation. Through single factor and orthogonal experiments, the dosage of regulator, depressant, activator, and collector were confirmed. NaOH dosage is800g/t, DF dosage is500g/t, CaO dosage is200g/t, and SMO dosage is400g/t. The flotation closed circuit test is shown that it can get the flotation concentrate grade of68.97%, recovery of98.25%; and tailing grade of16.39%, recovery of1.75%.In addition, principle of magnetism process and reverse flotation is discussed. The zeta-electric potential on the surface of quartz and the mechanism of interaction between flotation regents and ore are also discussed.