Experimental Study On Efficient Hydrometallurgy Leaching Of Tellurium Copper Slag And Recovery Of Tellurium

Tellurium,as a kind of rare metal,has important applications in electronics,metallurgy,chemical industry,and so on.Recently years,the demand for tellurium has been increasing.In this paper,the high efficiency wet leaching of copper telluride and the separation of copper and tellurium from copper anode sludge were studied.（1）The XRD analysis of the copper slag showed that the bismuth in the slag mainly existed in the form of bismuth and copper compounds.XRF analysis of copper slag showed that copper content accounted for 39.27%,bismuth accounted for 26.61%,sulphur accounted for 5.24%,and arsenic accounted for 1.15%.（2）Firstly,the thermodynamic analysis of copper leaching was carried out.According to the analysis results,the suitable hot-pressing alkaline leaching process and oxidizing acid leaching process were determined.（3）Thermodynamic analysis shows that under alkaline pressure conditions,bismuth forms the bismuth oxide into the solution,and copper forms copper oxide in the slag.The hot-pressure oxidation alkali leaching method uses oxygen as an oxidant and conducts a high-temperature press test in an autoclave.The results showed that at a temperature of 150°C,a pressure of 0.7 Mpa,a liquid-solid ratio of 5:1,a NaOH concentration of 3 mol/L,and a reaction time of 2 h,the leaching rate of bismuth was95.56%,and the copper content in the leaching solution was basically zero.（4）Thermodynamic analysis shows that copper telluride can be dissolved in acid in the presence of oxidant,bismuth is formed into bismuth,and copper forms copper ions.In the oxidative acid leaching experiment,H₂O₂ was used as the oxidant and sulfuric acid was used as the leaching agent.The leaching experiment was carried out,and various influencing factors were systematically investigated.The results show that at a temperature of 85°C,the H₂O₂ excess coefficient is 1.3,the liquid-solid ratio is 6:1,the H₂SO₄ concentration is 80g/L,and the reaction time is 2h.The leaching rate of bismuth is over 99%,and the copper leaching rate is also reached.More than 99%,the components in the leaching slag are mainly precious metals such as gold and silver.（5）The oxalate ion and the copper ion can form an insoluble matter having a low Ksp value.A copper sink experiment was carried out by adding Na₂C₂O₄ to the acid leaching solution.The results show that at a reaction temperature of 80°C,the Na₂C₂O₄excess coefficient is 1.3,and the reaction time is 2h,the precipitation rate of copper is above 99%.（6）Sodium sulfite and telluric acid can be subjected to a reduction reaction to obtain an elemental hydrazine.The copper-thickening liquid was added to a saturated solution of Na₂SO₃ to carry out an experiment of reducing hydrazine.The results show that at a reaction temperature of 80°C,the Na₂SO₃ excess coefficient is 1.6,and the reaction time is 3h.The reduction ratio of ruthenium is over 94%,the ruthenium content in the reduction slag is about 95.32%,and the ruthenium content is about 2.02%.It is about 0.58%.Compared with the hot-pressing alkali leaching process,the oxidizing acid leaching process is simple in operation and saves cost,and the acid immersion liquid can be directly reduced to obtain coarse enthalpy after being subjected to copper immersion.