| Tellurium is widely applied in the area of metallurgy, electronics, chemicals, glass, ceramic, pharmaceutical and so on. Especially, It is not irreplaceable in the new energy and advance materials, national defense and cutting-edge technology, which is considered an important strategic resource by many countries and governments. However, output of tellurium is less than lOt/a in our country, and 30t of tellurium have been consumed every year. So, we have to import 20t tellurium from other countries.It is estimated that the tellurium prospective reserves of independent tellurium ore deposit maybe up to 2000t, but because the tellurium grade is generally lower. Besides, the poor tetradymite ore has a close associated relationship with each other and the disseminated grain size of valuable minerals heterogeneous. The components of tellurium ore are very complex with high sulphur content. Moreover, some pyrite in flotation is similarity to tetradymite, which increases the difficulty in separation from each other. These characteristics prevent the beneficiation recovery of the refractory tetradymite ore. It is of great significance to strengthen the effect of collecting tetradymite and depressing pyrite as well as improving flowsheet to exploit independent tellurium ore deposit and alleviate the tellurium supply and demand.Base on the differences in surfece properties of tetradymite and pyrite, choosing efficient collector of tetradymite and efficient depressant of pyrite is a very important way.In this paper, it has shown from massive condition tests that the selective separation of tetradymite from pyrite could be achieved with sodium diethyl dithiocarbamate and butyl xanthate as mixed collector, Calcium oxide, sodium silicate and sodium sulfite as mixed depressant. A comprehensive recovery of valuable elements such as Te and sulphur realize a concentrate with a Te grade of 18.94% and recovery of 91.40% and a S grade of 40.39% and recovery of 90.69% is obtained by the process of magnetic-flotation separation, solving the common problem of the separation of tetradymite and pyrite. The results provide important technical guidance of the resources comprehensive utilization in Sichuan.Research of action mechanism between flotation reagents and minerals showed that Calcium oxide, sodium silicate and sodium sulfite as a mixed depressant can get full play synergistic effect on pyrite. Firstly, they can produce Ca(OH)2, Fe(OH)2, Fe(OH)3, CaSO3, CaSO4, SiO(OH); and Ca[SiO(OH)3]2, which will be selective sorption on minerals surface and increase the mineral hydrophilicity; Secondly, sodium sulfite has a function of removing the collector and active metal ions adsorption on pyrite, and it also can consume the oxygen of dissolution in pulp, reducing the pulp potential and hydrophobic production, minimizing the flotability of pyrite; In addition, sodium silicate still can reduce the micro fine and slime covering on minerals, which gives remarkable reduction of agent consumption and improves the selectivity of the collector. From the test date, adsorption measurements and Zeta potential measurements, we can conclude that the collector sodium diethyl dithiocarbamate has strong collecting ability and good selectivity for the tetradymite. The interaction mechanism of sodium diethyl dithiocarbamate with tetradmite and pyrite has been studied by adsorption measurements, Zeta potential measurements and FTIR spectroscopic analysis, and the results show that sodium diethyl dithiocarbamate is chemically adsorbed on tetradymite surfaces while the adsorption of pyrite is physical adsorption. |
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