Tin plate detinning
One of the first recycling processes
Tin plate is a relatively young material, which only came into wider use in the 19th century. Normal (tin-free) steel was refined with a tin coating, which made it resistant to corrosion or acids. The best-known examples of this were tin cans, which revolutionized food supply in expanding urban areas.
Since tin was a very rare and precious metal in the USA and Europe and, as well, an unwanted attendant material in the Siemens Martin steel production process (based on the melting down of tin waste), the separation of tin plate waste in starting metals promised to become a lucrative business.
This was recognized by the young Karl Goldschmidt, recently appointed Director of Chemische Fabrik Th. Goldschmidt, who began experimenting accordingly in 1882. Partly in collaboration with chemist Josef Weber, Karl Goldschmidt developed several pioneering, world leading processes for detinning tin plate; initially by electrolytic means, then from 1905 using chlorine and finally from 1911 also using alkali lye. All the detinning processes used internationally today are ultimately based on these developments.
The global success of detinning transformed Goldschmidt over the long-term and it became a large-scale enterprise; in 1911 it became a joint stock corporation, for the first time taking on an international orientation due to the need for a global purchasing organization for tin plate. In the decades that followed, detinning remained Goldschmidt's core business.
Profits however declined, the thickness of the tin coating continually decreasing while energy and staff costs increased. By 1974 Essen tin plate detinning had to be subsidized; final closure in 1990 was inevitable.