Separation Mechanism And Process Of Selective Flotation Separation Of Hematite And Apatite

High phosphorus iron ore is a kind of typical complex refractory ore.China's high phosphorus iron ore reserves ore considerable with good mining condition,but because of the presence of phosphorus,its use value is limited.Phosphorus is a kind of harmful impurity in iron concentrate,and the iron ore with more phosphorus in the smelting process will lead to"cold crisp" phenomenon.It is difficult to achieve effective separation of iron and phosphorus minerals for high phosphorus iron ores.If we solve the key technical problems of ore dressing,this kind of iron ore resources will become an important iron ore resource.At the same time,with the development of metallurgical industry and new technology,the requirement for the content of phosphorus in iron concentrate is also more stringent,but domestic mining enterprises lack the key technology and method to produce high quality iron concentrate,so that the quality of China's iron ore raw materials is poor,iron ore supply gap is relatively large.Therefore,it is an important measure to realize the deep removal of phosphate minerals in iron concentrate,so that the products can meet the needs of the market to the greatest extent and relieve the pressure of iron ore imports and to ease the difficulties faced by domestic mines.In this paper,the mechanism and the process of selective flotation of hematite and apatite were studied,the surface electrical properties of apatite and hematite,the interaction between mineral surface and sodium oleate and soluble starch were studied,the flotation characteristics between apatite and hematite were determined,reveal the intrinsic law of the separation of two mineral flotation,and the effective separation of the two minerals was realized,which can provide the theoretical basis for flotation dephosphorization of high phosphorus and iron ore.Pure mineral tests show that:pH=10,sodium oleate dosage 4 ×10-4mol/L are the best apatite flotation environment,the recovery rate of 93%.Hematite in the weak acid environment flotation effect is better.The addition and dosage of starch have a certain effect on the flotation of hematite and apatite,but hematite is especially affected by starch,when the dosage of starch increased from Omg/L to 80mg/L,the hematite recovery rate decreased by nearly 30%.When the starch content was 40mg/L,the difference between the recovery rate of hematite and apatite was 70%.The dissolution characteristics of hematite and apatite in aqueous solution,the results of dissolution of ions and solution pH on the mineral surface show that:the dissolution of apatite in the deionized aqueous solution was rapid and the pH was 8.1 when the equilibrium was dissolved.The pH value of the hematite in the deionized water solution was almost unchanged.The concentration of Ca2+ dissolved on apatite surface and the concentration of Fe3+ dissolved on hematite surface decreased with the increase of pH value.PH=10.5,the content of Ca2+ was 19.4mg/L,and the content of Fe3+ was 2.21mg/L.The results of Zeta potential measurement show that:sodium oleate adsorbed on the surface of hematite and apatite.The addition of 40mg/L starch,hematite surface Zeta potential decreased,starch adsorbed on the surface of hematite;apatite surface Zeta potential overall variation of starch and apatite surface interaction degree is not obvious.The results of XPS analysis and the IR spectra of the mineral surface with the agent(sodium oleate and starch)show that:At pH = 10,the—COO-groups in the sodium oleate were chemically adsorbed on the surface of hematite and apatite,respectively,and the corresponding oleate components(iron oleate and calcium oleate)were formed respectively.So as to promote its hydrophobic floating,resulting in the difficulty of selective flotation separation;Starch and hematite have obvious chemical adsorption and physical adsorption,hinder the sodium oleate in the mineral surface of the chemical adsorption and inhibition;The effect of starch on the surface of apatite is very weak,which has little effect on the flotation characteristics.This is the root cause of the selective separation of hematite and apatite by starch.The binding energy of iron 2p electrons was 0.28eV before and after the action of sodium oleate and hematite,and the chemical state of Fe atoms on hematite surface drifted,indicating that—COO—groups in sodium acid were adsorbed on the hematite surface by chemical action,Which shows the characteristic properties of the oleate component,indicating that sodium oleate has a chemical adsorption on the surface of hematite;In the hematite and starch,the binding energy of the iron 2p electrons was 0.25eV,and the chemical state of the Fe atoms on the hematite was drifted.At the same time,the FeOOH peak appeared at the surface peak after the hematite(—OH)and the Fe on the surface of hematite were studied.The starch was chemically adsorbed on the surface of hematite.This creates favorable conditions for the selective flotation separation of hematite and apatite.Based on the previous theoretical research,the actual mineral TFe grade is 57.08%,P is 0.45%with hematite high phosphorus iron concentrate,using reverse flotation dephosphorization process,the iron concentrate with iron grade of 58.75%and phosphorus content of can be obtained by one step roughing with NaOH 800g/t,starch 1200g/t and sodium oleate 400g/t,and the dephosphorization rate is about 65%.This paper provides a theoretical basis and technical support for the reverse flotation dephosphorization of high phosphorus iron ores.