Manufacture of Tin Metal

Enriched cassiterite ore, tin oxide concentrate, is heated with coke to about 1200°C in an electric furnace. This temperature is very high compared to the melting temperature of metallic tin, 231°C. It is used in order to obtain a fluid slag. Part of the tin will go into the slag as tin silicate and has to be reduced in a second stage. Crude tin metal is refined by different methods, finally by electrolysis and, if necessary, also with vacuum treatment and zone melting. 

Tin is to some extent recycled from tinned steel. One method is dissolution in an aqueous solution of sodium hydroxide and sodium nitrate. The tin is dissolved without attacking the steel. Tin is precipitated from the solution by electrolysis. 

The world tin metal production was 290 000 tonnes in 2001, of which 92% was primary, thus reduced from enriched tin ore. China produced the largest quantity (32% of the total). Other large producing countries were Indonesia (17%), Peru (13%), Malaysia (11%), Thailand (7%) and Brazil (5%). The United States also had a 5% share, totally based on secondary production. 

Manufacturing of bronze was once the principal use of tin. This is no longer the case. Only 10% of all tin is utilized for bronze. The use of tin in different alloys is treated in other chapters according to Table 42.2. 

Wood s metal consists of bismuth, lead, tin and cadmium. It has a melting range between 50 and 80°C. Rose s metal, an alloy of bismuth, lead and tin, melts at about 100°C. It takes its name from the German chemist and pharmacist Valentin Rose Sr. (1736-1771). Tin is used as one component in bdl metal, a type of bronze. The use of tin in ornaments and household articles has been treated above in connection with tin in history. 

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