Combined Beneficiation Process Of Low-grade Niobium-tantalum Ore

Niobium-tantalummetalischaracterizedbycorrosion resistance,superconductivity,unipolar conductivity and high strength at high temperature,which is widely used in high-tech industries.Although China is rich in niobium and tantalum resources,it is limited by small deposit size,low ore grade（almost no more than 0.02%）,fine disseminated grain size,complex mineral composition,and extremely difficult to separate.It is difficult to obtain ideal concentrate products by conventional single beneficiation method.Therefore,the joint beneficiation process test research has important theoretical and practical significance.A low-grade niobium-tantalum ore was studied by single gravity separation,magnetic separation,flotation and combined beneficiation.The research showed that the single hydraulic classification-shaking table gravity separation process,weak magnetic-high magnetic magnetic separation process and flotation process could not achieve the ideal enrichment and recovery effect for niobium and tantalum,and the suitable separation process for ore samples is"Gravity-magnetic separation-flotation"combined process.First,the sample was ground for 1 min after hydraulic classification,and the classified overflow product was magnetically separated under the condition of a strong magnetic field of 1800 KA/m;the classified underflow product was obtained under the condition of shaking table inclination angle of 7.5°to obtain mica coarse and refined with a yield of 9.79%.The heavy minerals products were subjected to magnetic separation under the conditions of a weak magnetic field strength of 50 KA/m and a strong magnetic field strength of 1500 KA/m after 15minutes of grinding.Comprehensive gravity separation-coarse concentrate obtained by magnetic separation process was subjected to the flotation open circuit test.In the experiment,the p H value of the pulp was 9,the amount of water glass was 1000 g/t,the amount of lead nitrate was 400 g/t,the amount of octyl hydroxamic acid（OHA）was 400 g/t,and the amount of methyl isobutyl methanol（MIBC）was 100 g/t.under the condition of g/t.After four selections,a flotation concentrate with Nb₂O₅grade of2.6544%and Ta₂O₅grade of 1.1682%was obtained,the recoveries were 54.31%and49.78%,respectively.The flotation concentrate was artificially panned and stripped to obtain a niobium-tantalum concentrate with a comprehensive grade of 8.8016%,and comprehensive recovery rate was 29.75%.The Nb₂O₅and Ta₂O₅grades were enriched from 0.0136%and 0.0064%of the original ore to 6.4048%and 2.3968%.The flotation test of niobium and tantalum single mineral was carried out,and the types of collectors,effects of slurry p H and chemical concentration on the flotation rate of niobium and tantalum single mineral were investigated.The results showed that OHA can have a good collection effect on niobium and tantalum single minerals,and lead ion activation can significantly reduce the dosage of OHA.Under the conditions of p H 9,lead nitrate concentration of 50 mg/L,and OHA concentration of30 mg/L,the floating rate of niobium-tantalum single mineral was 98.08%.The flotation mechanism of OHA in the flotation of niobium-tantalum ore under the activation system was discussed by means of chemical analysis of flotation solution,Zeta potential,contact angle and infrared spectroscopy.The results showed that OHA can have strong chemical adsorption on the surface of niobium-tantalum ore,when the p H was 9.OHA molecules and ions co-adsorb on the surface of niobium-tantalum ore by hydrophobic association,Lead was adsorbed on the surface of niobium-tantalum ore in the form of Pb（OH）⁺,which promoted the adsorption of OHA and increases the surface contact angle of niobium-tantalum ore,enhanced hydrophobicity.