銅電解スライム塩素浸出残渣から回収した塩化銀中の不純物元素の化学的形態および選択的溶解除去

概要

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A new hydrometallurgical process has been developed of silver recovery from chlorine leaching residue of anode slime in copper electro-refining, which includes the leaching of residue with aqueous Na2SO3 solution of pH=10.5 for 1h and at 25°C, followed by recovery of crude silver chloride at pH=1.0 with addition of 70% aqueous H2SO4 solution to the leaching solution and its purification with scrubbing by using various aqueous solutions of 6 kmol m-3 HCl and 30wt% H2O2, or 0.1 kmol m-3 EDTA at the temperatures ranging from 50 to 70°C. In this process, lead, selenium and tellurium are representative impurities in the crude silver chloride. Based on some chemical condition, it is speculated that the crude silver chloride contains mainly silver selenide and silver telluride as impurities. Scrubbing the silver chloride with HCl-H2O2 aqueous solution was effective to eliminate these impurities from the silver chloride. On the other hand, it is difficult to eliminate lead with the scrubbing, indicating that lead is incorporated in the silver chloride crystal. However, EDTA solution was effective for the elimination of lead to the level of less than 10 ppm.
社団法人資源・素材学会の論文
2007-10-25