Comprehensive Recycling And Mechanism Research Of Low-grade Refractory Ilmenite

As an important strategic resource,titanium resources are widely used in chemical industry,petroleum,medical treatment,aerospace and other fields.Although ilmenite resources are abundant in reserves,most of them show the characteristics of poor,fine and miscellany,and the separation efficiency of ilmenite is very low.With the increase of mining intensity,the disseminated particle size of the ore becomes fine,which makes it difficult to recover the useful minerals.Moreover,the association of ilmenite and gangue minerals is becoming more and more complex,leading to lower and lower grade of useful minerals,which is the main problem in the separation of ilmenite at present.In this paper,taking an Iran ilmenite as the research object,the process mineralogy of the ore sample was firstly studied,and the mineral processing was deeply explored through the ore properties,and the conditions of the magnetic field strength,dosage of reagents and other elements were systematically tested.Based on these results,the characteristics flotation of single mineral test was carried out for titanite and pyroxene,and the mechanism between reagent and minerals was preliminarily explored.The process mineralogy study shows that in this ore,ilmenite and magnetite are useful minerals,and gangue minerals are mainly composed of pyroxene,plagioclase,hornblende,chloridonite,plagiochlorite,albite and so on.The magnetic iron that can be recovered exist in only very small quantities in raw ore,with a metal distribution rate of only 23.66%.Other magnetic iron that can be recovered was distributed in the silicates(59.67%)and could not be used.In addition,75.17%of the titanium in the raw ore is distributed in ilmenite.Moreover,phase analysis shows that the theoretical maximum recovery of iron in ores is only about 20%and that of titanium is about 75%.In the magnetic separation process of ilmenite,the iron concentrate with Fe grade of 61.68%and recovery of 14.91%was finally obtained by weak magnetic separation,under the condition of grinding fineness of 85%in-200 mesh and magnetic field strength of 0.11T.In the iron concentrate,V2O5 was enriched to 1.57%which reaches the valuation standard of vanadium in iron concentrate and increases the added value of iron concentrate.The titanium concentrate of magnetic separation with Ti O2 grade of 24.61%and recovery of 70.5%was finally obtained by strong magnetic separation.In the flotation process,through the condition experiments of collector MOH,p H regulator H2SO4,depressant oxalate and LD-C,it is concluded that the flotation indexes is the best when the reagent dosage were 1500 g/t,1500 g/t,200 g/t and 20 g/t,respectively.The flotation titanium concentrate with a Ti O2 grade of 46.19%and a recovery of33.77%can be finally obtained by using the best reagent system after determining the flotation open-circuit experimental process of one roughing,three cleaning and one scavenging.On the basis of open-circuit flotation,closed-circuit flotation was carried out.In this process,titanium concentrate of closed-circuit flotation with Ti O2 grade of46.52%and recovery of 69.23%was obtained.Ultimately,titanium concentrates with Ti O2 grade of 46.52%and recovery of 48.81%were obtained in the whole magnetic-flotation combined process.Single mineral characteristics flotation of ilmenite and pyroxene shows that LD-C has the best effect in the separation of ilmenite and pyroxene.LD-C can strongly depress pyroxene but has little effect on the flotation of ilmenite when its dosage is2mg/L.According to the research on mineral crystal structure and flotation solution chemistry of ilmenite,a large number of Ca²⁺,Mg²⁺,Si²⁺is exposed on mineral surface after pyroxene being crushed.Then the carboxyl group and hydroxyl group in LD-C can react with these metal cations on the surface of pyroxene,so that LD-C can adsorb on the mineral surface and increase the hydrophilicity of pyroxene surface.What's more,ferrous ions on the surface of ilmenite become the main sites for collector adsorption under weak acid or base conditions.According to the infrared spectrum analysis of ilmenite and pyroxene,the depressant LD-C has weak adsorption on the surface of iron ore,but has strong chemical adsorption on the surface of pyroxene.The zeta potential of ilmenite and pyroxene shows that LD-C has little effect on the adsorption of MOH on ilmenite surface,and LD-C and MOH can co-adsorb on ilmenite surface.But for pyroxene,the adsorption of LD-C can hinder subsequent MOH adsorption on pyroxene surface,so that pyroxene can be depressed.