Study On Flotation Separation Scheme Of Rutile From Eclogite Ore And Adsorption Mechanism Of Agents On Mineral Surface

Rutile deposits in China are mainly divided into primary rutile deposits and placer deposits.It is widely known that primary rutile ore is considered as the main deposits in China due to its large reserves,accounting for 86%of the total amount.In this type of rutile deposits,the eclogite type rutile deposits is expected to become an important rutile resource development direction in China because of its abundant reserve,highly value in use of associated gangue minerals and shallowly buried body.In eclogite rutile ore,because of its fine grain size and complex associated relationship,which leads to smaller discrepancy between valuable mineral and gangue mineral in surface properties.In addition,the grinding process set before flotation is able to cause the slurry muddy,and the reagents used for flotation seem to be less effective.All of these deficiencies are considered to be the dominant factors that impair the flotation efficiency.According to above issues,we find a green chemical agent(dodecylamine polyoxyethylene ether)that can be used as the collector in rutile flotation.So we choose this type of collector as the alternative and investigate its application and accessibility in rutile flotation.In addition to flotation experiments,zeta potential measurements,FTIR and XPS analyses were conducted to investigate the adsorption mechanism.Additionally,we conducted the experiments using pure minerals and picked the styrene phosphoric acid(SPA)and sodium fluorosilicate(SF)as the collector and depressant,respectively.During this process,in order to investigate the detailed depression mechanism of SF on almandine,experiments of different reagents concentration,zeta potential measurements,contact angle measurements and XPS analysis were carried out.Furthermore,we picked the eclogite type rutile ore from Jiangsu province as the raw materials,trying to optimize the floatation scheme and on the basis of effective separation of rutile from almandine,mitigating the adverse effect caused by slimes.(1)From the results we find that,new green chemical collector dodecylamine polyoxyethylene ether performs well in collecting rutile particles instead of almandine.It is worth mentioning that with increasing EO numbers in collector,the collecting ability reduces in turn.This is because that larger steric hinder effect results in less adsorption density of agents on mineral surface.The presence of iron and aluminum ionic species in slurry could impair the recovery of rutile.Compared to iron ionic species,aluminum ionic species seem to have stronger depressing effect since Al(OH)₃ precipitate can act with Ti-OH sites to form Ti-O-Al,thereby shading the active sites for adsorption of collectors.According to the results of Gibbs free energy,it can be found that Fe(OH)₃ is less steady so it tends to coat on the rutile surface through weak physical interaction.The adsorption mechanism between collector and rutile surface is mainly due to the fact that the tertiary amine group could protonate in weak acid region because of its lone pair electrons,then protonated amine group can act with negatively charged rutile surface through electrostatic force effect.In addition to electrostatic interaction,there is a hydrogen bonding between neutral tertiary amine groups with Ti-OH sites as well.(2)Alternatively,when using SPA as the collector,the addition of depressant sodium fluorosilicate is able to achieve a well separation.The sodium fluorosilicate is believed to inhibit the almandine through Si F₆^2-species acting with the Fe active sites to form a Fe-F chemical bond.In that way,there is no extra Fe active sites for collector adsorption.(3)For real ore flotation,with increasing the slime contents in feed samples,there is an enrichment of slimes in flotation concentrates,which significantly reduce the grade and recovery of Ti O₂.A desliming pretreatment set before flotation is expected to a perfect approach for mitigating the detrimental effects caused by slimes.When using one rough and two scavenging flowsheet and setting lead nitrate,SF,SPA,water glass as 300 g/t,800 g/t,600 g/t,200 g/t,respectively,a concentrate with grade 52.56%,recovery 79.58%could be obtained.