Process
- raw cassiterite is introduced into furnace
- the cassiterite ore is then roasted over coal in which the carbon from the coal and the oxygen in the cassiterite combine and leave Tin solid and CO2 gas
- the slag is drained off and is then cooled
- the resulting slag is still impure as the initial smelting only removes some impurities such as iron and coper
- it is then reheated until just above tin's melting point (tin has a low melting point and so it will liquify before the other compounds) and then is drained into a separate kettle
- the pure tin is then poured into 100lb ingots guarunteed to 99.99% purity
