Study On Separating Titanium And Scandium From V-Ti Magnetite Tailings In Panxi Region Of China Using A New Beneficiation-Metallurgy Process

The Panxi area is the main gathering place for the development of vanadium-titanium magnetite resources in my country.After long-term development of vanadium-titanium magnetite resources,the stockpiles of vanadium-titanium magnetite tailings produced in the process of beneficiation have increased year by year,not only occupying Land resources,and also have a greater impact on the surrounding environment,so the comprehensive utilization of vanadium-titanium magnetite tailings has important practical application significance.This research takes the vanadium-titanium magnetite tailings produced by a concentrator in Panxi area as the research object,and develops a new technology and mechanism for the efficient recovery of valuable metals titanium and scandium.This research provides a suitable technical solution for the separation and extraction of titanium and scandium from vanadium-titanium magnetite in Panxi area.The study of process mineralogy shows that the main mineral components of the tailings used in the experiment are ilmenite,magnetite,pyrite,pyroxene,plagioclase,serpentine,chlorite,mica and amphibole.Titanium mainly exists in ilmenite.Most of scandium exists in pyroxene,mica,feldspar and other minerals in the form of isomorphism.High intensity magnetic separation and flotation were used to recover titanium from vanadium titanomagnetite tailings.The results show that the magnetic field strength of the tailings H=0.8 T and feed grain size of?0.15 mm accounting for 95%,which can preliminarily separate the crude titanium concentrate.The crude titanium concentrate uses ST as collector and CMC as inhibitor,titanium concentrate with Ti O₂ grade of 45.41%and titanium recovery of 63.87%was obtained through the closed-circuit flotation process of"once roughing,once scavenging,and five cleanings"under the condition of flotation pulp p H=3.After vanadium-titanium magnetite undergoes a combined process of magnetic separation and flotation to recover ilmenite,scandium is further enriched.From vanadium-titanium magnetite tailings to scandium crude concentrate,the Sc₂O₃ content increases to 44 g/t.The research shows that key technology to recover scandium is to release scandium ions from the interlayer structure of ore and make it into soluble state.In this paper,different processes of roasting-leaching for scandium extraction are proposed,the research shows that:Chlorine activated roasting-leaching process conditions are as follows Mg Cl₂ dosage is 50%of the ore weight,roasting at 900?for 2 h,roasting slag is leached by hydrochloric acid,and the scandium leaching rate is 32.51%;2)The alkali melting roasting leaching process conditions are as follows Na₂CO₃ dosage is 45%of the ore weight,roasting at 900? for 2 h,leaching acid concentration is 6 mol/L,leaching time is 2 h,leaching liquid-solid ratio is 6?1,leaching temperature is 50?,and the leaching rate of scandium is 60.94%;3)The optimum conditions for the fluoride salt enhanced dissolution leaching process the amount of Ca F₂ accounts for 30%of the weight of the ore,the leaching acid concentration is 4 mol/L,the leaching liquid-solid ratio is 8:1,the leaching time is 4 h,and the leaching temperature is 80?.Under these conditions,the leaching rate of scandium can reach 72.22%,and the content of scandium in the leaching residue is 13.72g/t.Considering comprehensively,the fluoride salt enhanced dissolution leaching process is more reasonable as the scandium extraction process,which can obtain the ideal scandium extraction technical index.The scandium-extracted raw ore and the leaching residue before and after the enhanced dissolution-leaching process of the fluoride salt were compared,and it was found that only feldspar mineral phases existed in the leaching residue.Further research found that under the action of fluoride salt,the structure of layered silicate and chain silicate were destroyed,and only the structured framework silicate remained.The mechanism of leaching scandium in this process can be explained as:fluoride salt generates hydrofluoric acid under strong acid conditions,and hydrofluoric acid reacts with the Si?O structure of layered silicate and chain silicate minerals to produce[Si F₆]^2-With[Al F₄]^-,this completely destroys the structure of pyroxene,mica,chlorite and other minerals.Scandium metal can react with acid to enter the leaching solution,while the structure-stable framework silicate mineral remains intact.