Refining Tin in a Reverberatory Furnace
Tin is a metal that is mainly used for corrosion resistance or to harden other metals. While traditionally tin was mined and worked by hand, today this process is much more mechanized. One of the most efficient methods to refine tin is to use a reverberatory furnace.
A reverberatory furnace is an open-top, sloping hearth furnace used to separate the impurities from certain metals. This type of furnace has a roof that is lower than the hearth and allows the hot gasses created by combustion to escape. The ore being refined is loaded into the furnace located on an inclined hearth, then heated with coal or coke. The heat source also provides a source of air for the fire.
When the tin ore is placed in the furnace it immediately reacts with some of the oxygen, producing carbon dioxide and metal vapors. This process increases the temperature of the metal, which in turn causes the remaining impurities to form oxides and slag. The slag is then removed from the top of the furnace using a scoop, while the metal is tapped at the base of the furnace.
The tapping process is essential to the refinement of tin. When the furnace reaches the correct temperature, molten tin is tapped off and then poured into molds. This molten tin is now considered matte, meaning that the most of the impurities have been removed and the metal is ready for further refining.
The matte is heated in a converter, which uses oxygen and air to complete the refining process. During this process, the metals within the matte react and form “converter slag,” which is removed. This leaves a pure tin puddle in the bottom of the converter, which can be cooled and solidified into tin ingots.
By using the reverberatory furnace and proper refining methods, tin can be removed from ore quickly and efficiently. This refining process is largely automated, meaning that large quantities of ore can be processed in a reasonable amount of time. The refined tin is then often used in a variety of applications, such as waterproofing and soldering.
