The Study Of Dashuigou Tellurium Bismuth Wet Method Metallurgy Technology

In the modern society,there is the growing demand for all kinds of rare earth elements to people with a variety of functional materials appeared.Tellurium is widely used in metallurgy,electronics,chemical and glass industry because it is a special properties of rare earth element.Currently,the tellurium is from copper refinery anode mud and acid mud,which is not only with its low production,but also with its limited sources of raw materials,and it is unable to meet the increasing demand of tellurium.Therefore,the development in tellurium bismuth ore as raw material of tellurium process is more important.The raw material is Dashuigou high-grade tellurium bismuth ore from ya’an in sichuan province.First of all,it should analysis ore mineral composition and content.The second is research ore roasting pretreatment,hydrochloric acid,sulfuric acid leaching and the process conditions of extracting tellurium.Finally,form the process of tellurium bismuth ore metallurgy.This thesis has analysised Dashuigou tellurium bismuth ore and found that it contains tellurium,bismuth,iron,calcium and sulfur.Among them,the content of tellurium is 4.61%,the content of bismuth is 3.68%,the content of iron is 21.22%.The subject takes the method of metallurgical process,the pretreatment stage is crushing the tellurium bismuth ore and roasting 4 hours at 450℃in the muffle furnace,make the elements in the ore fully oxidized.The sulfur is directly oxidized to sulfur dioxide and remove.The loss of tellurium is 5%after roasting.After roasting ore and crushing to 90%over 200 mesh.The hydrochloric acid leaching process condition is that the liquid-solid ratio is 3:1,temperature is 20℃,leaching time is 2.5h,the leaching rate of tellurium is 97%.The sulfuric acid leaching process conditions as follows:the liquid-solid ratio is 4:1,join the polyacrylamide type crystal modifier to quality 0.2%of ore in the sulfuric acid,leaching 3h under 70℃,the leaching rate of tellurium was over 85%.In this paper,extraction separation tellurium technology is from the hydrochloric acid leaching liquid,in order to solve the problem of iron and tellurium,it has used two different leaching liquid extraction system of extraction of tellurium.First of all,use the volume fraction of 60%P507 to extract the iron in tellurium bismuth ore hydrochloric acid,the experiment has investigated the tellurium bismuth ore leaching liquid c(H~+),extraction series,extraction temperature,extraction time,extraction of iron compared to the influence of extraction rate.The results is that the c(H~+)=0.5mol/L,the rate(O/A)is 1,the extraction time is 5min,extraction temperature is 20℃,4 cross-flow extraction conditions,the extraction rate of iron is above 99.9%,and tellurium is loss less than 2%.The reverse extraction process has studied the extraction temperature,reverse extraction time,the reverse extraction of(O/A),reverse extraction liquid concentration on extraction rate.The Result is that the reverse extraction temperature is 20℃,reverse extraction time is 10 min,reverse extraction rate(O/A)is 1,the reverse extraction solution c(H~+)is 2 mol/L,eventually reverse extraction rate of iron was 99%.The second is that take the volume fraction of70%TBP as the extractant to extract the leaching liquid after the separation of iron,the experiment has explored the influence of the extraction time,extraction rate(O/A)and extraction series.The experimental results is that extraction time is 2 min,extraction rate(O/A)is 0.5 and 2 levels of cross-flow extraction conditions,the tellurium extraction rate was over 99%.The reverse extraction phase is used to be extraction agent,the experiments has explored influence of the extraction temperature,extraction time and extraction rate.The result is that the extraction time was 1.5 min,reverse extraction rate(O/A)is 1.5,reverse extraction temperature is 20℃,the reverse extraction rate of more than 97%.It will get reverse extraction liquid containing tellurite after extraction with distilled water,the tellurite was dried in 100℃about 4 hours to weighing after filtering,the solid is the tellurium dioxide products.The tellurium yield of this topic development of tellurium bismuth ore metallurgy process was 88.21%,the product of tellurium dioxide purity is 99.75%.