Flotation Process Of Vanadium Titanomagnetite Tailings In Northwest Liaoning And Mechanisms Of Flatation Reagents

In China,there are more than 90%of titanium resources existing in the form of ilmenite in vanadium titanomagnetite deposits,and recovering ilmenite from vanadium titanomagnetite ore has been the main way to obtain titanium resources.These years some huge ultra-low grade vanadium titanomagnetite reserves have been found in the northwest area of Liaoning,China.However,due to the particularity of the ore,the iron concentrate of conventional beneficiation for this ore contains too much titanium but less iron content than the requirement from iron-smelting industry,and the ilmenite concentrate has a low TiO2 grade.Based on the process mineralogy research and flotation solution chemistry analyses,in this paper a new flotation process was proposed and investigated to recover ilmenite from the tailings of magnetic separation for this kind of vanadium titanomagnetite ore,and a series of research results were achieved as follows.The process mineralogy studies of the products from conventional beneficiation for this kind of ultra-low grade vanadium titanomagnetite ore revealed that there were 15.02%ilmenite and 21.54%gangue minerals in the iron concentrate,and titaniferous magnetite therein contained 10.99%of TiO2,all of which were the main reasons leading to low iron grade in iron concentrate product.Magnetic separation tailings contained 14.48%of TiO2 which was valuable to be recovered and flotation would be a promising method to separate it.The grain sizes of this tailings were relatively coarse,and most of ilmenite in the tailings were interlocked with a variety of gangue minerals.In addition,there were a small amount of hematite and magnetite in this tailings,which would affect the recovery efficiency of ilmenite.The result of ion dissolution test and analyses of flotation solution chemistry indicated that the iron tailings in acidic conditions dissolved out a large number of metal ions,these metal ions and its complex would have adverse effects on flotation process.In order to decrease the effects of these ions and its complex,and considering point of zero charge of ilmenite as a critical influence factor,acidity of pulp in flotation tests was set as neutral(pH value was about 7.0).It was found in the flotation tests that ilmenite could be floated from the tailings under neutral conditions and a good separation result was obtained when NaOL-SHA compound was used as collector.The effects of particle size and collector dosage on the floatability of ilmenite were studied after the tailing sample was ground.It was found that the best results were obtained when the fineness of flotation feed reached the proportion of-74μm grains accounting for 70%by weight,and the concentration of NaOL-SHA compound collector in the pulp was 770 mg/L.High intensity magnetic separation could be used to remove the fine sludge in the tailings after ground,resulting the TiO2 grade of the magnetic separation concentrate up to 19.66%,which was beneficial to improving ilmenite flotation.Applying depressants was helpful to improve the TiO2 grade of the flotation concentrate.Experiments showed that(NaPO3)6 had the best effects on the ilmenite floatability among the three depressants tested.An open-circuit flotation process was designed as one rough separation and four cleaning concentrations to beneficiate the tailings,and the test results showed that when(NaPO3)6 was used as the depressant,the grade of TiO2 in the concentrate IV was higher,but the recovery rate was very low due to the high loss of ilmenite during cleaning separations.In order to improve the TiO2 grade of the concentrate as well as obtain a relatively high recovery,(NaPO3)6 was used as the depressant with some NaOL-SHA additionally added during the thirdstage cleaning separation of the open-circuit flotation,which led to a much better beneficiation result.Based on these investigations,it can be concluded that the process of ball milling—high intensity magnetic separation—flotation including one rough separation and three cleaning separations can be used to obtain an ilmenite concentrate product with a TiO2 grade of 47.31%and recovery of 57.71%from the tailings.The flotation solution chemistry analyses revealed that(NaPO3)6 and its hydrolyzed components adsorbed on the surface of gangue minerals,increased the hydrophilicity of gangue minerals and inhibit prevented them from floating;SHA anion was bound to the titanium and iron site on the ilmenite surface in the form of fivemember ring,and NaOL was adsorbed on the iron site in the form of oleic acid ionmolecular association in the pulp.So it can be speculated that the two components of collector interacted on the ilmenite surface in the way of intersperse and co-adsorption,so as to improve its hydrophobicity and separate from gangue.In this study,a new flotation separation process of ilmenite in neutral pulp environment was obtained,which improve the grade of TiO2 without reducing the recovery rate of ilmenite,and has a reference significance for the enrichment and recovery of ilmenite from the iron separation tailings of vanadium titanomagnetite in northwest Liaoning Province.