| With the rapid development of the national economy, the contradictions between supply and demand of mineral resources are becoming increasingly acute. In order to meet the demand of steel production in China,exploitation of iron ore resources used with difficulty is extremely urgent.For exploiting xuanlong iron ore resources and providing a technical and economic feasible reference for oolitic hematite resource with similar nature,we carry out mineral processing technology research of xuanlong iron ore.The research of magnetic roasting-grain growth-magnetic separation process on fine grained surface iron ore showed that when the raw ores is ground to-0.074mm accounting for59.03%, roasted at a temperature of800"C for45min, reductant to ore ratio of8%,the percentage of roasting products with a grinding finenessof-0.045mm is65.85%and the magnetic field intensity is105.6kA/m,the high quality iron concentrate with an average grade of more than62%ang iron recovery of more than85%can be obtained.And with the roasting temperature between750℃and850℃, reductant to ore ratio between8%and14%, roasting time between30min and60min, a good separation effect also can be obtained,which indicated that magnetic roasting-grain growth-magnetic separation process on fine grained surface iron ore has a good controllability and reproducibility. Optimizing process conditions of the same process on mixed iron ore,the iron concentrate with an average grade of62.6%ang iron recovery of84.4%can be obtained,which indicated the process on xuanlong oolitic hematite ore has an universal applicability.The grain growth of magnetite was confirmed through optical microscope, SEM-EDS and XRD,which has important academic value and process value.Reverse flotation was carried on iron concentrate.which had been handled by magnetic roasting-grain growth-magnetic separation for obtaining more high grade iron concentrate. Using conventional flotation reagents,such as sodium oleate, starch, and calcium oxide, flotation effect was studied in detail. When the dosage of sodium oleate, starch and calcium oxide are500g/t,900g/t and3000g/t,pH at12, grinding fineness of-0.074mm87.9%,the iron concentrate with an average grade of64.1%and iron operation recovery of84.5%can be obtained.There is no any effect when adding dispersant sodium hexametaphosphate and sodium silicatethe. The increase on grade of iron concentrate through magnetic roasting-grain growth-magnetic separation process is limited when using conventional flotation reagents sodium oleate, starch, and calcium oxide.In order to overcome the disadvantage that sodium oleate can’t be used at low temperature flotation,the research on the choice and compound of collector was carried on. New self-developed anion collector OMC-1, OMC-2is easily soluble in water,and can be used for10-12℃low temperature flotation.When the dosage of OMC-1, starch and calcium oxide are700g/t,1000g/t and4000g/t,pH at12, reverse flotation has a good effect, the iron concentrate with an average grade of63.9%ang iron operation recovery of87.8%can be obtained. There is a synergistic effect between OMC-1and OMC-2, When the ratio OMC-1and OMC-2is4:1, the dosage of starch, calcium oxide and collector are1000g/t,4000g/t and700g/t, the iron concentrate with an average grade of64.3%ang iron operation recovery of84.45%can be obtained. The increase on grade of iron concentrate through reverse flotation is limited when using the present collector,the reagent dosage of reverse flotation is large and has a high production costThrough a comprehensive comparative analysis, magnetic roasting-grain growth-magnetic separation process is the best process when dealing with xuanlong hematite... |
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