Research On Recovery Of Iron Minerals From Oxidized Iron Tailings Of Nanfen Processing Mill

With the large-scale development and utilization of iron ore resource,the amount of iron ore resource decreases increasingly.As second resource,iron mineral recycling from iron tailings has been concerned.The amount of oxidized iron ore treated in the plant of Nanfen mill is about one million tons a year.Along with the changes of ore properties,the iron silicate content of crude ore increased,which deteriorate the result of separation.It causes the low iron recovery and immense waste of resources.In this paper,using the tailings of Nanfen mill as the research object,on the foundation of technology mineralogy research,recovery experimentals are carried out systematically and the appropriate process flowsheet was confirmed.Chemical component analysis and X-ray diffraction analysis on tailings showed that iron grade of tailing was 18.57%.The iron minerals in the tailings were mainly magnetite and hematite,while the gangue mineral was mainly quartz.Size analysis suggested that the coarse grain dominated in tailings,the single liberation degree is low.For iron minerals preconcentration from the tailings,high intensity magnetic separation was selected as enrichment process with product of iron grade 24.99%and recovery 88.74%.Subsequently,the grinding fineness test and low intensity magnetic separation condition test were carried out,which gives suitable grinding fineness-0.045mm 50%and the magnetic field strength 79.58kA/m,and product of the grade of low intensity magnetic concentrate 66.09%,and the recovery 29.39%.The tailings of low intensity magnetic separation is fed into high intensity magnetic separation,the concentrate grade is 25.05%was 25.05%with recovery of 85.71%.The high-intensity magnetic concentrate was used as direct and reverse floatation materials.The factors which have effects on flotation include grinding fineness,the pH value,and the dosage of depressant,activator and collector.In reverse flotation process,sodium oleate was as collector,the appropriate condition of roughing was obtained:the content of-0.045mm is 67.19%,pH value 10.0,starch dosage 800g/t,calcium oxide dosage 400g/t and sodium oleate dosage800g/t.In reverse flotation closed-circuit test of one-roughing and one-cleaning and one-scavenging,concentrate with grade 54.29%,recovery 69.44%was obtained.Finally,concentrate and tailings of reverse flotation were conducted characteristics analysis,and the factors which have effect on flotation concentrate grade were analyzed.The results of this paper has some guiding significance on iron minerals recycling from the tailings of Nanfen workshop.