Electrowinning Copper Recovery from Spent Baths
废液电解回收铜与贵金属捕集
标签：电解回收, 废液处理, 阴极铜, 硫化沉淀, 环保合规
镀铜与酸蚀废液含 Cu²⁺ 1–10 g/L，直排超标且浪费。采用不锈钢阴极 + DSA 不溶性阳极电解回收，电流密度 0.5–2 A/dm²、槽压 2.5–4 V，可将 Cu²⁺ 降至 50 mg/L 以下，阴极铜片纯度 99% 以上，直接回售或回溶补槽；尾液再投加硫化钠沉淀残余铜后达标排放。含金银的退镀洗液用锌粉置换或离子交换纤维捕集，年度回收量往往可抵消电费。回收台账须留档备环保核查，回收率计入物料平衡。
Copper plating and pickling wastes carry 1–10 g/L Cu²⁺—over discharge limits and wasteful. Electrowinning on stainless cathodes with DSA anodes at 0.5–2 A/dm² and 2.5–4 V drops Cu²⁺ below 50 mg/L; copper sheets over 99% pure are sold back or redissolved. Residual copper in tail liquor is precipitated with sodium sulfide before compliant discharge. Gold/silver stripper rinses are scavenged by zinc cementation or ion-exchange fiber—annual recovery often offsets power costs. Keep recovery ledgers for environmental audits.