Study On Metallurgical Separation Method Of Tin - Rubidium - Refractory Tungsten

Shizhuyuan Polymetallic Mine is the biggest tungsten resources all over the world. However, the ores is hard to separated and utilized comprehensively because of its low grade and the complicated composition. A novel process used to treat containing rubidium from Shizhuyuan(Hunan province) by vacuum reduction、High pressure alkaline leaching process and sodium roasting-water leaching process is proposed in this paper, which overcomes the flaw that tungsten and tin cannot be extracted well from low-grade mixed W-Sn ores respectively in view of the existing techniques.(1) Vacuum reductionComparing the tin volatilization with vacuum reduction and vacuum sodium reduction, the results show that, when the content of carbon was 1% of the ores; when the content of carbon was 0.5% of the ores, and the addition of sodium carbonate was 1.2 times, meanwhile, the time of sodium reduction process was above 60 min under the temperature 1200 ℃, tin volatilization rate came up to above 98%. The separation of tungsten and tin can be achieved through the vacuum reduction process, in which tungsten cannot be reduced so that kept in the slag.(2) High pressure alkaline leaching processSodium hydroxide-sodium carbonate pressure leaching process was selected through the comparison of different leaching agent. And the experimental results show that over 98% WO3 is extracted from tungsten ores at the optimum technological conditions. The optimum technological conditions are as follows: the moral ratio of sodium carbonate is 1.5 times, liquid-solid ratio is 5:1, partial pressure of oxygen is 0.5MPa, leaching temperature is 180℃, leching time is 2h, stirring speed is 700r/min. The primary separation of tungsten and tin was achieved, which alleviated the burdan of impurity removal.Solvent extraction from the leaching liquor can be utilized in the separation of tungsten.The extraction rate of tungsten can reach about 70% at the optimum technological conditions using N235. After 3 stages of counter-current extraction,the rate came up to 99%.(3) Sodium roasting-water leaching processSodium roasting-water leaching process was used to separate tungsten and tin towards low-grade mixed W-Sn ores.Under the optimum process condition, the leaching rate of tungsten was above 98% and the leaching rate of rubidium was about 90%. The optimum technological condition of Sodium roasting-water leaching process is listed as follows. The addition of sodium carbonate was 30% of the ores, then roasted 2 hours under the temperature 850℃. The roasted product leached for 2 hours in water at 95℃, and the ratio of solid-to-liquid was 4:1.Rubidium separated and purified by solvent extraction from the liquor, under the optimum solvent extraction conditions and after 3 stages of counter-current extraction, the extraction rate of rubidium could reach above 99%. The optimum solvent extraction condition is listed as follows. The liquid was extracted 3 minutes by 30% t-BAMBP+70% sulfonated kerosene, the O/A was 1.5/1; The experimental results showed that tungsten can be absorbed by anion exchange resin, D201-W. And the adsorption ratio of W was above 98%, the loaded resin with tungsten was desorbed with 1mol/L NaOH+2mol/L NaCl under the contact time, and the desorption ratio of W was above 98%; the leach sludge was treated with 6mol/L hydrochloric acid for 2 hours at 85℃, meanwhile the liquid-solid ratio was 4:1, the results show that the leaching rate of tin was above 85%.