The unique properties and excellent wear and cutting resistance of the tungsten and its carbides made them a highly valuable commodity and strategic metals around the world. As such, tungsten scrap is also highly valued and becomes a significant source of tungsten raw materials and so is their sustainability. To be specific, cemented carbides which are utilised in producing components and tools for cutting metals, drilling rocks, and for other applications that require high resistance to wear. These tools are highly useful in the construction, manufacturing, mining, gas drilling, and petrochemical sectors. All of which containing tungsten becomes available for reuse and recycling.
When it comes to recycling cemented carbide, there are three primary methods that are used. These include direct, indirect, and semi-direct. The direct method of recycling tungsten scrap offers the benefits of the high recovery of the metal, better grain size control, and good quality of powder production. However, it requires energy-intensive and costly equipment to totally separate the metal carbide from the material that bonds it.
On the other hand, the indirect method of recycling has the ability to produce highly valuable “virgin ammonium para tungstate” or APT which is needed in producing other tungsten intermediate products. The major drawback of this method is the need to go through various conversion steps before tungsten carbide scrap can be separated. The last option is the semi-direct recycling method that requires low energy and environmental impact but employs slow process kinetics.
Reports indicate that tungsten scrap will be a significant source of raw material for the entire tungsten industry in the near future. This is why recycling efforts should focus on optimising the current methods while putting emphasis on the purity of the scrap metal, energy costs, recovery of valuable tungsten constituents, and reduced environmental impact. Any new recycling method to be developed must also consider all these factors to ensure that valuable tungsten scrap is fully recovered.