Sulfuric Acid Dissolution of Panzhihua Ilmenite Under Simultaneous Milling

The feasibility of rapid leaching of Panzhihua ilmenite in sulfuric acid through combined milling under industrially employed acid/ore mass ratio was investigated.The effects of the stirring speed of attritor,milling ball/ore mass ratio,reaction temperature and sulfuric acid concentration on the dissolution were examined.The results show that with the simultaneous milling and dissolution the 1 h Ti leaching rate was 64% higher than that without milling under the otherwise same conditions due to lattice deformation and noticeably refined particles resulted from the milling.Optimized leaching conditions were obtained as follows: stirring speed at 700 r/min,ball/ore ratio at 5∶ 1,acid/ore ratio at 1∶ 1.6,sulfuric acid concentration at 70% and temperature at 120 ℃.Under these conditions,a titanium leaching rate of 81% was reached in 60 min and the stability of the titanyl sulfate solution thus obtained was higher than 550 mL.Therefore,direct digestion of ilmenite in 70% of sulphuric acid solution is feasible,which can fully reuse the hydrolyzed waste sulfuric acid discharged in the sulfate pigment production.