(中南大學 冶金與環(huán)境學院，長沙 410083)
摘 要: 提出一種基于微電流作用下的提鎘新工藝，采取正交試驗考察各工藝參數對海綿鎘提取過程的影響，并對ZnSO4+CdSO4混合溶液中Zn2+、Cd2+的陰極行為進行電化學研究。結果表明：各因素對提鎘率的影響由大到小的順序依次為溫度、pH、極距、電流密度、陰陽極面積比；最佳工藝條件為pH=1、極距3 cm、電流密度400 A/m2、溫度90 ℃、陰陽極面積比1:2，在此條件下電置換1 h提鎘率達到79.31%；鎘先于鋅在陰極析出，當鋅開始析出時，溶液中鎘離子濃度已降到很低，最低可降至0.528 mg/L。混合溶液陰極沉積的表觀活化能為6.379 kJ/mol，在60~90 ℃時屬于擴散步驟控制。
關鍵字: 鎘；微電流；鋅板置換；電化學
（School of Metallurgy and Environment, Central South University, Changsha 410083, China）
Abstract:A new process of cadmium extraction under micro-current was proposed. In order to determine the optimum process parameters, five main effect factors were investigated by an orthogonal experiment. Electrochemical experiments of the cathodic behavior of Zn2+, Cd2+ in mixed solution of CdSO4+ZnSO4 were conducted. The results show that the influence factors on extraction rate decrease in such an order: temperature, pH, polar plate distance, current density, plate area ratio. The optimal conditions are obtained at pH of 1, polar plate distance of 3 cm, current density of 400 A/m2, temperature of 90 ℃ and plate area ratio of 1:2. The maximum extraction rate is 79.31%. Cadmium is prior to precipitate than zinc. The concentration of Cd2+ in solution decreases to the minimum of 0.528 mg/L while zinc begins to deposit. The apparent activation energy of deposition is 6.379 kJ/mol. The diffusion-controlled is the dominant process at temperature ranging in 60-90 ℃.
Key words: cadmium; micro-current; zinc plate cementation; electrochemistry
