Study On Hydrometallurgical Technology Of Bismuth Telluride Ore

Tellurium, a scattered metal with special physical and chemical properties, is widelyapplied in the area of metallurgy, electronics, chemicals, glass and ceramics,pharmaceutical and so on. Especially, It is not irreplaceable in the new energy andadvance materials, national defense and cutting-edge technology, which was consideredan important strategic resource by many countries and governments. In1991, the world’sfirst independent tellurium ore was found in dashuigou of Sichuan Province, Thehigh-grade ore is extremely rare and the average content of tellurium is0.08%. The oldprocess of extraction is developed for the copper anode mud and acid mud, whichgenerally require the content of tellurium no less than4%. It is a comprehensiverecovery of gold, silver, copper, selenium and tellurium. Not only the recoveries oftellurium and the associated metal is well, but also the technology is mature. However,these processes require the equipment well and huge investment, consume lots of energyand so on, at the same time low-grade bismuth telluride ore is not applicable. It is ofgreat significance to study and develop new technology to use dashuigou low-gradebismuth telluride ore and alleviate the tellurium supply and demand. In this paper, takingthe low-grade bismuth telluride ore as the object, based on the analysis of the ore contentand forms, so that we can explore a hydrometallurgical technology in recycling oftellurium.In this paper, The bismuth telluride raw ore and bismuth telluride concentrates afterflotation were analyzed by X fluorescence spectrometry. The results showed that the oremain contains Iron, bismuth, tellurium, sulfur, Their all as the form of Sulfide. Bismuthtelluride concentrates after flotation contains22.85%of Iron,1.12%of bismuth,1.03%of tellurium.Bacteria had been used to leaching ore in the research, The bacterial was obtainedfrom acid water and soil near mining area, which subculture in the leaching medium.The mixed bacteria that used in leaching experiments was domesticated three times.Bacteria and sterile, temperature, initial pH and liquid-solid ratio were studied. Theoptimization conditions are as follows: the temperature is30℃, the initial pH is1.5, andthe liquid-solid ratio is50. Under the conditions the leaching rate of tellurium is75.8%after15days.The process of extraction and separation of Te（Ⅳ） and Fe, Bi from leachingsolution step-by-step by using isopropyl ether and TBP. First, Fe was extracted byisopropyl ether in hydrochloric acid, the acid, the proportion of organic to aqueous and the time were studied in the experiment. Comprehensive consideration of E_Fe, ETe, EBi,β_Fe/Teand β_Fe/Bi, the optimization extraction conditions are as follows: the acid is7.2mol/L, the ratio is0.75and the time is90seconds. Under the conditions of thisextraction, the E_Feis98.87%, the E_Teis1.89%, the EBiis1.07%, the βFe/Teis52.31andthe β_Fe/Biis91.55, the separation between Iron and tellurium, bismuth are effective.Different concentrations of hydrochloric acid was chosen as stripping agent, the timeand the ratio was studied in the experiment. The optimization stripping conditions are asfollows: the stripping agent is distilled water, the time is60seconds and the ratio is1.Under the conditions of this stripping, the stripping percentage of Iron, tellurium andbismuth is respectively94.18%,99.80%and99.76%. The loaded organic phase can bestripping well and the isopropyl ether that was stripping has a very good extractionperformance, cycle using isopropyl ether can save costs.Second, extract tellurium from the solution that after extraction of iron. The type ofdiluents, the concentration of extractant, the acid, the ratio and the time were studied inthe experiment. Comprehensive consideration of ETe, E_Biand β_Te/Bi, the optimizationextraction conditions are as follows:30%TBP-kerosene system, the acid is7.2mol/L, theratio is0.5and the time is120seconds. Under the conditions of this extraction, the ETeis96.82%, the E_Biis0.92%, the βTe/Biis105.2, extraction of tellurium is effective, at thesame time, the separation of tellurium and bismuth is effective. Types of stripping agent,the time and the ratio were studied, Under the conditions of this stripping: the strippingagent is distilled water, the time is3minutes, and the ratio is1, the stripping percentageof tellurium and bismuth is respectively95.70%and99.80%.High-purity tellurium products can be extracted from the solution, which has beenpurified by extraction. The recovery of tellurium is90.91%.