Regeneration of Hard Alloy Wastes by Low Energy Consumption and Environmentally Friendly Hydrothermal Technology

Abstract

Hard alloys are indispensable material for many branches of modern industry. However, even with the base composition (WC-Co) they are quite expensive due to the limited natural resources of cobalt and the complexity of their production from the minerals. Therefore, the collection and recycling of hard alloys waste have not only scientific but practical importance, taking into account that the cost of production of 1 ton of alloy from recovered waste comes to 20% cheaper than in the core technology. Existing methods of hard alloys waste treatment have several disadvantages, the main of which are high power consumption and big load on the environment. As a result of this research a high-performance, low-energy consumption, eco-friendly way for recycling of hard alloys waste has been proposed. According to this technology, in a first step the WC powder, and the solution containing cobalt salts were obtained by autoclaving at 230 °C in a mixture of HCl-H3PO4-HNO3 acids, and followed then metal cobalt recovery from hydrothermal solution at temperatures of 110 – 160 °C.