| The resource of titanium mainly consist of ilmenite is abundant in China.However,due to the low TiO2 grade and the high content of impurity,it can not be used directly for production of chloride and titanium sponge,and it is only used by sulfate process as raw material.Chlorination process would be trend of society and economic development,since the pollution is serious by sulfate process.Due to the high grade request of raw material by using chlorination process to produce titanium dioxide,thus,it is indispensable to transform ilmenite into high grade rich-titanium material for the development of titanium industry.In this paper,the blast furnace slag and high titanium slag as raw material from Panzhihua Steel were taken as research project,made analysis by X-ray fluorescence,scanning electron microscopy,X-ray diffraction and other modern microscopic test.According to the properties of titanium slag,the route of sodium roasting-water immersion-acid leaching-alkali leaching-roasting can be determined.In addition,the factor of sodium roasting,acid leaching and alkali leaching were systematically investigated.The main research contents and results were as follows:(1)Properties of titanium slag showed that both of blast furnace slag and high titanium slag had low grade,and the mineral phase were anosovite solid and silicate minerals.It shows the essence of improving TiO2 grade lies in removing silicate minerals and the major impurities from anosovite solid in titanium slag.The phase composition of sodium roasting showed that the higher roasting temperature,the better for destruction of magnesium-aluminum spinel and the perovskite gathered in blast furnace slag.But in the high titanium slag the highly roasting temperature is benefit for destruction of anosovite solid and perovskite.(2)The research of sodium roasting study showed that under the conditions that the dosage of Na2CO3 0.55,rosting temperature 880? and time 1h,and then the roasted producted was leached on condiction time 1h,temperature 80?by water,15%hydrochloric acid on condiction time 3h,temperature 90? and then 2mol/L alkaline,time 2h,temperature 80?,the blast furnace slag containing 80.73%TiO2,91.56%recovery was obtained.And under the conditions that the dosage of Na2CO3 0.40,rosting temperature 920? and roasting time 1h,and then the roasted producted was leached by same condition as blast furnace slag,high titanium slag containing 90.65%TiO2,93.16%recovery was obtained.(3)The study of acid leaching showed that blast furnace slag containing 88.74%TiO2,91.18%recovery was obtained under the condition was that hydrochloric acid concentration 20%,leaching time 3h,leaching temperature 90 ?,and then alkaline leaching.Besides,high titanium slag containing 94.17%%TiO2,92.90%recovery was obtained under the condition that hydrochloric acid concentration 20%,leaching time 1h,leaching temperature 90 ?,and then alkaline leaching.Acid leaching removing impurities was studied that the occurrence of Ca in blast furnace slag is different from high titanium slag.In blast furnace slag impurity Ca was mainly in form of perovskite,but it was in form of silicate minerals in high titanium slag.(4)The study of alkaline leaching showed that the best alkaline leaching condition for blast furnace slag was that NaOH concentration 3mol/L,time 1h,temperature 80?.On this condiction,Al2O3 leaching rate was 2.38%and the leaching rate of SiO2 was 94.25%.Besides,the alkaline leaching condition that NaOH concentration 2mol/L,leaching time 2.5h,leaching temperature 65 ? was best for high titanium slag.On this condiction,Al2O3 leaching rate was 21.27%and the leaching rate of SiO2 was 74.25%.The research showed that the route of sodium roasting-water immersion-acid leaching-alkali leaching-roasting can remove impurities from blast furnace slag and high titanium slag effectively,improved the grade of TiO2.So the route has presented a new way for us to make full use of the rich titanium resources in China. |
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