Tin metallurgy and recycling

Tin is a metal whose production dates back to antiquity. Since it is no longer used in its pure state, the general public is likely to know it only through antique dealers or art object manufacturers: some may even be surprised to learn of its presence in bronze, tinplate or solder, which together currently account for almost three-quarters of the world's tin consumption. In fact, of these three industrial applications of tin, only solder contains it at high levels: bronzes generally only contain around 10%, and the tin layers making up tinplate only represent around 2 g/m ² per side.

From a technical standpoint, extractive tin metallurgy has had to adapt to concentrates that are poorer in tin and richer in iron, such as those derived from primary ores. In addition to reductive smelting, this has involved the volatilization of tin in the form of sulfide by adding pyrite to the slag bath, and more recently, processes combining this volatilization with the smelting of concentrates.

Finally, the quality requirements imposed on refined tin, particularly with regard to lead, have also given rise to certain developments in the refining field.

Tin recycling differs from that of other non-ferrous metals in that there is no real tin scrap and it is widely dispersed. In the case of used tinplate cans, recycling is relatively easier than for its competitor aluminum, but under what conditions for the steelmaker, given the harmful effects that residual tin can have during steel rolling? The debate continues... on an increasingly specifically Asian terrain; Asia, which accounts for over half of the world's tin mine production (55%), has increased its share of global consumption of this metal to the same level as that of the United States and the European Union combined. The future of tin will depend to a large extent on the Chinese tin-can market, and therefore on the initiatives taken by European steelmakers to participate in the construction of local tin-can factories, in order to capture a share of the market currently dominated by aluminum.