Effect Of Fine Chlorite On Flotation Characteristics Of Hematite In Reverse Flotation Process

Iron ore is one of the important mineral resources in China,which is related to China’s national economic problems.Chlorite,as a gangue mineral with more content in iron ore except quartz,has a significant effect on the separation of iron ore.In this thesis,the influence of fine chlorite on reverse flotation of hematite is studied by taking chlorite,quartz and hematite as research objects.Firstly,the adsorption behavior of starch and Ca Cl₂on the surface of minerals is studied by pure mineral adsorption characteristics test,and the adsorption isotherm model is constructed.The results show that the adsorption strength of starch on the surface of three minerals is:chlorite>hematite>quartz;under strong alkaline conditions,the adsorption strength of Ca Cl₂on the mineral surface is:chlorite>quartz>hematite.The analysis results of artificial mixed ore adsorption test show that the content of fine-grained chlorite has a great influence on the surface of minerals.In order to achieve the original inhibition or activation effect of the agent,the dosage of the agent needs to be increased.The effects of pulp pH value and reagent dosage on the floatability of minerals were studied by pure mineral flotation test.Quartz and chlorite had the best floatability when p H=11.0 and Ca Cl₂dosage was 80 mg/L,while hematite had poor floatability and could achieve the purpose of mineral separation.The results of artificial mixed ore flotation test show that the best conditions for the co-floating of chlorite and quartz are p H=11.0,starch dosage 120 mg/L,Ca Cl₂dosage 160 mg/L,and sodium oleate dosage 150 mg/L.Compared with the pure mineral flotation test,the amount of Ca Cl₂increased significantly.The higher the content of fine chlorite is,the lower the grade of iron concentrate is.When the content of fine chlorite is 10%,the grade of flotation iron concentrate is 58.12%,and the recovery rate of iron concentrate is 93.24%.When 40 mg/L citric acid is added,the grade of iron concentrate is 62.33%,which increases by 4.21 percentage points,and the recovery rate is 92.20%,which only decreases by 1.04 percentage points.The contact angle of quartz and chlorite became larger after the action of sodium oleate,but the change of chlorite was relatively small.Secondly,starch adsorbs on the surface of chlorite and hematite by chemical adsorption,and mainly hydrogen bonding on the surface of quartz.The adsorption between Ca Cl₂and the three minerals is electrostatic adsorption,and the fitting results of adsorption isotherm model show that there is a certain chemical adsorption between chlorite and Ca Cl₂.The oleic acid ion produced by the hydrolysis of sodium oleate in solution interacts with Ca²⁺and Ca（OH）⁺adsorbed on the surface of quartz and chlorite to achieve the purpose of collecting quartz and chlorite.Citric acid can act on the surface of hematite and chlorite in the form of citric acid anion,and increase the electronegativity of hematite and chlorite surface,resulting in the increase of electrostatic repulsion between the two,so as to achieve the purpose of dispersing ore particles.