Li Mingjing, Huang Baozhen, Chen Weinan, Huang Zexi, Wang Haijun, Huang Jianhua, Liu Chunjia, Barati Mansoor, Huang Liuqing
College of Materials of Xiamen University, Xiamen, 361005, China; Shenzhen Research Institute of Xiamen University, Shenzhen, 518055, China.
Xiamen Tungsten Co., Ltd, Xiamen 361009, China.
J Hazard Mater. 2024 Sep 15;477:135384. doi: 10.1016/j.jhazmat.2024.135384. Epub 2024 Jul 30.
The treatment of spent cemented carbides using the conventional alkali-acid leaching process results in the generation of hazardous solid waste tungsten leaching residue. This study proposed an alternative process using the alkali-treated tungsten leaching residue (AW-residue) without the acid leaching step, preserving Co in the residue. By using photovoltaic silicon kerf waste (SKW) as a reducing agent, heavy metals (Co, Ni, W, Nb, and Ta) were efficiently extracted from AW-residue and a Co-rich alloy was obtained. The silicothermic reduction process facilitated the recovery of iron group metals (Co, Ni, and Fe) and effectively captured trace refractory metals (W, Ta, and Nb). Phase separation occurred through reduction reaction and viscosity-driven processes between the Co-rich alloy and the slag. Optimal conditions were identified as 20% SKW addition, MgO crucible, and a holding time of 120 min, achieving a total recovery yield of 95.5%, with specific yields for Co (97.7%), Ni (97.0%), W (82.5%), Nb (76.3%), and Ta (70.5%). A 20 kg pilot-scale experiment confirmed the feasibility of the process, yielding 47.0% Co-rich alloy from AW-residue compared to 48.3% in lab-scale experiment, and producing a harmless slag phase. This environmentally friendly approach promotes sustainable recycling of valuable metals in the tungsten industry.
采用传统的酸碱浸出工艺处理废硬质合金会产生有害固体废弃物钨浸出渣。本研究提出了一种替代工艺，即使用经碱处理的钨浸出渣（AW渣），无需酸浸步骤，从而将钴保留在渣中。通过使用光伏硅切割废料（SKW）作为还原剂，从AW渣中高效提取了重金属（钴、镍、钨、铌和钽），并获得了富钴合金。硅热还原工艺促进了铁族金属（钴、镍和铁）的回收，并有效捕获了微量难熔金属（钨、钽和铌）。通过还原反应以及富钴合金与炉渣之间的粘度驱动过程实现了相分离。确定的最佳条件为添加20%的SKW、使用氧化镁坩埚以及保温120分钟，总回收率达到95.5%，其中钴的回收率为97.7%、镍为97.0%、钨为82.5%、铌为76.3%、钽为70.5%。一项20千克的中试规模实验证实了该工艺的可行性，从AW渣中获得了47.0%的富钴合金，而实验室规模实验中的这一比例为48.3%，同时产生了无害的炉渣相。这种环保方法促进了钨行业中贵重金属的可持续回收利用。
