The mechanical processing of cemented carbide often generates a considerable amount of grinding waste from cemented carbide (GWCC), which serves as an important secondary resource for recovering Co and W. However, efficient separation of tungsten carbide (WC) and Co from GWCC remains challenging. This study tested an efficient process for separating Co from GWCC using a mixed solution of H2SO4-Na2S2O8. Under optimum conditions of 20 g/L H2SO4, 30 g/L Na2S2O8, 60 °C, and 1 h, the leaching efficiency of Co reached 97.0 %, compared to only 58.6 % when using H2SO4 alone. The kinetics of Co leaching in H2SO4 and H2SO4-Na2S2O8 solutions were determined to be a combination of chemical reaction control and diffusion control, suggesting that Co leaching rate in H2SO4 solution is significantly enhanced by introducing Na2S2O8. Finally, complete recovery of Co was achieved, and pure Co powder with a flower-cluster morphology was prepared from the leaching solution through oxalic acid precipitation followed by vacuum pyrolysis. The regenerative WC and Co powder can be recycled for cemented carbide production.

中文翻译：

---

使用硫酸-过硫酸钠混合溶液从硬质合金磨削废料中高效分离和回收钴


硬质合金的机械加工通常会产生大量的硬质合金 （GWCC） 磨削废料，这是回收 Co 和 W 的重要次要资源。然而，从 GWCC 中有效分离碳化钨 （WC） 和 Co 仍然具有挑战性。本研究测试了使用 H2SO4-Na2S2O8 的混合溶液从 GWCC 中分离 Co 的有效工艺。在 20 g/L H2SO4、30 g/L Na2S2O8、60 °C 和 1 h 的最佳条件下，Co 的浸出效率达到 97.0 %，而单独使用 H2SO4 时仅为 58.6 %。确定 Co 在 H2SO4 和 H2SO4-Na2S2O8 溶液中的浸出动力学是化学反应控制和扩散控制的结合，表明引入 Na2S2O8 显着提高了 H2SO4 溶液中的 Co 浸出速率。最后，实现 Co 的完全回收，并通过草酸沉淀和真空热解从浸出液中制备具有花簇形态的纯 Co 粉末。再生 WC 和 Co 粉末可以回收用于硬质合金生产。