School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083, China.
School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083, China.
Waste Manag. 2018 Jun;76:234-241. doi: 10.1016/j.wasman.2018.03.018. Epub 2018 Mar 13.
Continuous growth of the shipping industry and infrastructure has consumed large amounts of zinc-rich paint (ZP) for the protection of steel structures against corrosion. Consequently, a growing amount of waste zinc-rich paint residue (ZPR) is being generated from anticorrosion spraying. ZPR is classified as hazardous waste in most industrialized countries, but it contains considerable amounts of organic compounds with high calorific value and zinc species that can potentially be recycled. Most of the ZPR generated is not properly treated, and this study presents a simple and efficient process for recycling ZPR. The zinc in ZPR was recovered via a hydrometallurgical route through oxidative alkaline leaching and electrowinning. The results show that the leaching ratio of zinc was greater than 98% at 95 °C, NaOH concentration of 250 g/L, liquid/solid ratio of 10:1, air flow rate of 0.6 L/min, and leaching time of 1.5 h. The appropriate minimum concentration of zinc for electrowinning was determined to be 10 g/L. Adding 50 mg/L of gelatin to the electrolyte significantly refined the grain and the optimum current density was determined to be 200 A/m. Fern shaped cathode zinc powders with a purity of 99.8% were obtained. A high current efficiency (92.7%) was also obtained with energy consumption of 2330.3 kWh per ton of zinc produced. The composition and thermal analysis of the leaching residue suggest that co-processing in cement kiln may be suitable for disposing the leaching residue of ZPR. The experimental results show that the proposed process is promising for ZPR recycling.
航运业和基础设施的持续增长消耗了大量富锌涂料（ZP）来保护钢结构免受腐蚀。因此，越来越多的防腐喷涂产生了废富锌涂料残渣（ZPR）。ZPR 在大多数工业化国家被归类为危险废物，但它含有相当数量的具有高热值的有机化合物和锌物种，这些物质有可能被回收利用。大多数产生的 ZPR 没有得到妥善处理，本研究提出了一种简单有效的 ZPR 回收方法。ZPR 中的锌通过湿法冶金路线通过氧化碱性浸出和电解回收。结果表明，在 95°C、NaOH 浓度为 250g/L、液固比为 10:1、空气流量为 0.6L/min 和浸出时间为 1.5h 的条件下，锌的浸出率大于 98%。确定电解适当的锌最低浓度为 10g/L。在电解液中添加 50mg/L 的明胶可显著细化晶粒，最佳电流密度确定为 200A/m。获得了纯度为 99.8%的蕨形阴极锌粉。电流效率也高达 92.7%，每吨锌的能耗为 2330.3kWh。浸出残渣的成分和热分析表明，在水泥窑中共同处理可能适合处理 ZPR 的浸出残渣。实验结果表明，该工艺有望用于 ZPR 的回收。
