Facile recycling of cemented tungsten carbide soft scrap via mechanochemical ball milling

Abstract Sustainable recycling of cemented tungsten carbide (WC) is essential to solve supply issues and natural resource exhaustion caused by increasing demand. The recycling process should be efficient, ecofriendly, and economically viable, and the resulting product must have quality that is comparable or better than that of cemented WC prepared from virgin raw materials. Herein, we describe an efficient process for recycling cemented WC soft scrap using mechanochemical ball milling in the presence of sulfuric acid. The process is based on the synergetic effect of mechanical milling of scrap and chemical leaching of cobalt (Co). This method has the advantage that WC can be recovered without oxidation or phase change. The leached aqueous Co salts are precipitated as cobalt hydroxide (Co(OH)2) via pH titration, followed by reduction to obtain high-purity Co powder. The WC and Co purities were 98.04% and 98.07%, respectively. Consolidation of the recovered WC particles and Co powders provided recycled cemented WC having excellent mechanical properties.