Research On Production Of High Purity Iron Concentrates By Reverse Flotation Using Anionic Collector

With the international trade price of iron ores falling constantly in recent years,huge impact has been caused to the domestic mine enterprises of iron ores.Many iron ore companies run at serious losses and have a difficult to operate normally for the high production cost.Producing high purity iron concentrates by anionic reverse flotation will be a profitable direction for iron ore companies.High purity iron concentrates are more versatile in application and have higher additional value.In this paper,on the basis of analyzing and summarizing a mass of related domestic and oversea literatures,the research on production of high purity iron concentrates by anionic reverse flotation has been carried out.Pure mineral experiments and the real ore tests were conducted to investigate the flotation performance of anionic collector OMC-2.Zeta potential test,infrared spectrum analysis and contact angle measurement methods were taken to analyze the mechanism of the reverse flotation.It was found that the pH value has an effect on the floatability of quartz.Collector OMC-2 was appropriate to float quartz in alkaline conditions.Adding a small amount of Ca2+ into the pulp contributed quartz to obtain higher flotation recovery.Starch could strongly depress magnetite and had a greater influence on the floatability of magnetite.With OMC-2 as collector in the flotation of high grade magnetite(TFe61.20%),achieved the grade was 67.89%,the recovery was 91.06%of iron concentrate.Open-circuit flotation experiment was carried out then,through a roughing,two cleaning open-circuit flotation flowsheet.An iron grade of 71.09%,the recovery was 81.69%of high purity iron concentrate was gained.(1)Zeta potential analysis showed that the electric potential of activated quartz surface and inhibited magnetite shifted negative direction.The mineral surface showed strong electro negativity after reaction with reagents.The Zeta potential of quartz moved negative degree was bigger under the condition of high pH value;with the increasing of pH value,the negative movement of Zeta potential of magnetite was decrease.(2)Infrared spectrum analysis results showed that the infrared spectrum of quartz did not appear new features reflection peak.Physical adsorption between quartz and collector happened;Infrared spectrum peak migration of magnetite showed magnetite surface might have a chemical adsorption and hydrogen bonding interaction with starch.(3)Solution chemical calculation showed that when the pH value was low than 11 and the concentration of CaOH+ was low,the activation of quartz was not obvious;With pH value increasing,CaOH+ concentration increased to 104mol/L.At this point,CaOH+ had a strong activation on the quartz surface,then the recovery rate of quartz rapidly reached to 80%,so the hydroxyl complex CaOH+ played the main role of activation when a little Ca2+ was added.(4)The initial contact angle of quartz was 26.52°,the quartz surface acting with collector after activation of the addition of Ca2+,contact angle of quartz increased to 49.78°.With the contact angle of quartz increased,the floatability and flotation recovery got enhanced;the initial contact angle of magnetite was 26.73°,after acting with starch,the contact angle was increased to 35.58°.The flotation recovery rate of magnetite declined.It might be magnetite surface was depressed after reacted with starch.Then the depressed hydrophilic surface hindered the collector adsorbed in the surface of magnetite.