Study on Selenium and Tellurium Recovery from Gold-Precipitated Solution by Hydrochloric Acid-Catalyzed SO₂ Reduction AITranslate

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Chinese Library Classification Number:TF09[冶金工程]

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Using hydrochloric acid as a catalyst,selenium and tellurium were recovered from gold-precipitated solution by SO₂ reduction.The effects of concentrated hydrochloric acid dosage,reaction time and H+concentration on the recovery rates of selenium and tellurium were investigated.The phase and morphology of the reduction products were analyzed by XRD and SEM,respectively.Besides,a comparative study was conducted on the effects of sodium sulfite and hydrazine hydrate as reducing agents on the recovery rates of selenium and tellurium from gold-precipitated solution.The results show that when selenium and tellurium are recovered from the gold-precipitated solution via hydrochloric acid-catalyzed SO₂ reduction,the recovery rates of selenium and tellurium reach 99.63%and 97.14%,respectively,under the conditions of a reaction temperature of 85℃,a concentrated hydrochloric acid(36%)dosage of 6%of the volume of the goldprecipitated solution,a reaction time of 4 h,and a H+concentration of 5.1 mol/L.In the reduction products,both selenium and tellurium exist in elemental form,with a strip-like morphology interspersed with particles.When sodium sulfite is used as the reducing agent with a dosage of 7.58 times the theoretical amount,the recovery rates of selenium and tellurium are only 76.88%and 35.71%,respectively.When hydrazine hydrate(80%)is used as the reducing agent with a dosage of 2.5%of the volume of the gold-precipitated solution,the selenium recovery rate reaches 99.38%and the tellurium recovery rate is 92.86%.Comparative analysis indicates that sodium sulfite is not suitable as a reducing agent for selenium and tellurium recovery from the gold-precipitated solution.Although hydrazine hydrate as a reducing agent achieves high recovery rates,it exhibits a relatively high cost.By comparison,the hydrochloric acid-catalyzed SO₂ reduction process for selenium and tellurium recovery from the gold-precipitated solution not only delivers ideal recovery efficiency,but also offers advantages of simple operation and low cost,thus demonstrating greater development prospects.