Study On Floatation Performance And Mechanism Of Combined Collector In Andalusite Ore

Andalusite is a kind of aluminum silicate mineral with very stable physical and chemical properties.It is often used as refractory material and widely used in metallurgy,chemical industry and other industrial fields.The development of andalusite ore in China is relatively late,and the content of andalusite is low due to the existence of associated minerals,which requires enrichment before industrial application.Andalusite ore in Liaoning Province belongs to carbonaceous andalusite two-mica schist.Andalusite is hemihedral long columnar,and the phenocrysts contain about 25%biotite and 15%quartz,which makes it difficult to extract andalusite.Therefore,in order to achieve effective enrichment of andalusite and obtain qualified finished concentrate,this paper is mainly as follows:（1）Using sodium dodecyl sulfonate,polyamine collector and the combination of them in different proportions as flotation agents,the flotation experiments of andalusite,quartz and biotite were carried out,and the mechanism was explained by Zeta potential and transmission infrared ray test.In the single mineral flotation experiment,sodium dodecyl sulfonate can not separate andalusite and biotite.Compared with dodecylamine,polyamine collector can effectively separate andalusite and biotite,but both of them are difficult to separate quartz.In order to achieve the separation and purification of andalusite,polyamines was combined with sodium dodecyl sulfonate and flotation was carried out under the condition of mass ratio of1:4 and p H=2.The results show that the recovery rate of andalusite is 65%higher than that of biotite and quartz,and the synergic factor is greater than 1.Theoretically,the separation of andalusite from biotite and quartz can be realized,and the purpose of separating and purifying andalusite can be achieved successfully.Zeta potential test showed that the mineral surface potential increased greatly under the polyamine system.When the solution p H>2.5,the amine salt cation in the polyamine would combine with the negative charge on the surface of andalusite to form electrostatic interaction.When p H<2.5,the H atom in the amine salt cation of the polyamine will combine with the O atom on the surface of the andalusite to form a hydrogen bond.When the solution p H>2.1,polyamines are adsorbed on the quartz surface by electrostatic action.Sodium dodecyl sulfonate not only has electrostatic adsorption on andalusite surface but also forms strong chemical adsorption.Its adsorption of quartz and biotite is a physical adsorption.At p H=2,the H atom on the ammonium cation in the combined collector forms hydrogen bonds with the O atom in the andalusite,and the dodecyl sulfonate ion forms ionic bonds or donor-acceptor bonds with the Al atom in the andalusite lattice with unsaturated valence and coordination valence.The physical and chemical interactions occur at the same time,resulting in synergistic effects.However,there is only electrostatic adsorption on the quartz surface and the adsorption is unstable.In addition,the adsorption between andalusite and collector was further verified by transmission infrared ray test.（2）The quantum chemical simulation was used to further explain the binding mechanism of andalusite and collector.The andalusite crystal model was constructed and optimized by Materials Studio.The optimal construction conditions:the exchange correlation functional is GGA-WC,the truncation is 400 e V,and the k-point is 2×2×2.By CASTEP module,the adsorption energy of collector and crystal surface was calculated:sodium dodecyl sulfonate>polyamine>dodecylamine.By simulating the adsorption process,it is observed that sodium dodecyl sulfonate forms Al-O chemical bond on the surface of andalusite and produces chemical adsorption.There are obvious hydrogen bonds between polyamines and dodecylamines on the surface of andalusite.H atoms in polyamines form hydrogen bonds with O atoms,which connected with Al and Si.It indicating that the flotation between them and andalusite is carried out by physical adsorption.（3）In order to obtain qualified andalusite concentrate,the common collectors and different combinations of collectors were selected for actual mineral flotation experiments In the actual mineral flotation process,the process of one rougher flotation and four selective selection is used.By comparing the flotation results of single collectors such as sodium dodecyl sulfate,hydroxamic acid,sodium dodecyl sulfonate,polyamine and other single collectors and combined collectors,the closed-circuit experiment is finally determined to use the combined collector with the mass ratio of polyamine to sodium dodecyl sulfonate 1:4.The qualified andalusite concentrate with Al₂O₃taste of 56.22%,Al₂O₃recovery of 17.96%and Fe₂O₃content of 0.86%was obtained by adding 150 mg/g composite collector in rough selection and 60 mg/g composite collector in the first selection.