Metal processes and applications - an overview

As background to the other chapters a short overview of each metals’ physical properties, production process, applications and recycling is given. One way of approaching the elements is through their place in the periodic table of elements, which can be used to predict physical and chemical properties and behavior. Each group in the periodic table corresponds to a section in this chapter. Still how the metals relate to each other for a particular property is not directly apparent from the periodic table. They can be ranked based on density or melting point or strength which are important for structural applications. But metals are not only used for that. Some are used because of their ability to form alloys and improve alloy properties, to catalyze reactions or to conduct electricity or heat. The application also determines the purity of the metal. Whereas for ferroalloys a purity above 90% suffices, semiconductors such as silicon or germanium require over 9N purity. Extensive refining is necessary to achieve such purity. Another way to group the metals is by the method or equipment to produce and refine them.
This chapter is also suitable for a systematic approach. The linkages and similarities between the different metals become apparent, providing valuable insights for primary production (mining), recycling, residue treatment, technology development, alloy and product design, substitution, etc.
The metal wheel (figure2) is a key tool for this. It visualizes the interconnectedness between metals, which is particularly relevant for metallurgists in the context of metal refining and the circular economy. It applies to metals from primary resources, production rejects and end-of-life products, and residues generated within (metal) production and recycling processes. The metal wheel summarizes this chapter, and is also a guidance when designing products and assessing recycling possibilities of metal-containing products.