Study On Processing Of Low-grade Iron Ore And Preparation Of Super Pure Iron Concentrate

With the development of the iron and steel industry and the increasing attention of the state to environmental protection,the preparation of iron concentrate with high grade and low impurity is the development trend of iron ore dressing,and it is also an effective way to improve the economic benefit.This subject takes a low grade iron ore in Qinghai as the research object,and carries out the study of technological mineralogy,and combines the characteristics of the ore and the local geographic climate to determine the suitable ore dressing technology for low grade iron ore.The process of making ordinary iron concentrate into ultra-pure iron concentrate has been further studied.The concrete conclusions are as follows.(1)Investigation of ore properties: The iron ore belongs to the marine sedimentary rock type ore.The main iron minerals are magnetite,and the secondary iron minerals are ilmenite.The main gangue minerals are sericite,diopside and chlorite,followed by quartz,plagioclase and epidote,and the harmful impurities,S and P are low.Along the foliation of scattered magnetite and part of magnetite inergrowns with ilmenite,a small amount of magnetite is explained by hematite.The magnetite in ore belongs to fine embedding.The hardness and compressive strength of the ore are low,and the crushing and grinding process is easy to be crushed.(2)By comparing the product characteristics of the high pressure roller mill and the twin roll crusher,combined with the climate and environmental characteristics such as drought,water shortage,the processing technology of high pressure roller mill plus and “wind-gravity-magnetic separation” was determined.out.Using this process,the iron concentrate of Fe grade of 61.83%(magnetic iron grade of 60.52%)magnetic iron recovery rate of 74.79%.(3)By using the technological process of “fine grind-magnetic separation-reverse flotation-acid leaching”,in the conditions of grinding particle size of D90=21.39?m,magnetic field 23.87 k A/m,flotation inhibitor caustic starch dosage 500g/t,collector dosage of 50g/t for twelve amine,leaching temperature 60?,the leaching time 60 min,the concentration of sulfuric acid 60g/L,super pure iron concentrate which Fe grade is 71.82%,content of Si O2 is 0.47%,and the content of Al2O3 is 0.20% have get.Further acid leaching,by the concentration of sodium fluoride 12g/L,and the concentration of the pulp 25%,super pure iron concentrate that Fe grade is 72.02%,content of Si O2 is 0.24%,and the content of Al2O3 is 0.11% is made out.