Tin Processing
Tin processing is one of the most important methods for beneficiation of tungsten–tin ore. Tungsten is often found as complex compounds, in association with tin ore as cassiterite, which is an important source of this metal. Tin can also be found as oxides, silicates and sulfides, and generally it is found in conjunction with a range of other elements.
Tin is a useful metal due to its high electrical and thermal conductivity, low toxicity and ability to be alloyed with other metals. These properties are exploited in the many uses of tin, such as in solder, electrical fittings and tinplate. It is also used in the manufacture of chemicals and food packaging.
Tin ore processing begins with the milling of the ore, which is then separated magnetically. This magnetic fraction is then subjected to a process known as jigging, where separating particles are passed up and down in a pulsating water stream. These particles are then graded and flotation is used to separate out the more valuable ore from the impurities.
The ore is then crushed and ground, and the tin concentrate then separated from the tailings. The concentrate is then processed in order to recover tin from the ore. This is generally done in a process known as smelting. In this process, the concentrate is firstly subjected to a temperature increase of about 900 degrees Celsius in order to fuse the metal oxides together.
This processed ore is then subjected to a variety of chemical treatments in order to separate out the valuable tin. The different treatments used vary depending on the type of ore, but generally involve either a gravity or magnetic separator, froth flotation or leaching. The process of leaching involves the dissolution of metal ions from the ore in a solution containing a chemical such as sodium chloride or hydrochloric acid.
Once the tin has been removed, it is necessary to refine the metal in order to extract the pure form of tin. This refining process, also known as electrolysis, involves the passing of an electric current through molten tin and results in the formation of pure tin metal.
The resulting tin is then either melted in a crucible and poured into molds to cool, or is used to cast into various shapes. The casting process involves filling a mold with molten tin and allowing it to cool and solidify in the desired shape. This method is usually employed for creating thin, durable objects such as tin cans and decorative items.
Tin processing is an important aspect of the global economy, being used for the production of products such as solder, tinplate, food packaging and chemicals. The processes involved in this industry have advanced and improved significantly in recent years, enabling more efficient and effective extraction and refining of tin ore.
