Aluminum fluoride is an inorganic compound that is colorless, solid, and is typically made synthetically. It is a primary component used in the production of aluminum and is abbreviated AlF3.
Aluminum Fluoride and Electrolysis
Commercially, aluminum fluoride compounds are a critical additive in the production of aluminum. When combined with cryolite, AlF3 lowers the melting point of the solution below one-thousand degrees Celsius and in turn increases conductivity. Aluminum oxide is then dissolved into the molten solution and subsequently electrolyzed to create bulk AI metal. Cryolite, an uncommon mineral primarily mined in Greenland, is an essential component of the process.
The History of Aluminum Mining
In the late 1880s, scientists all over the world were searching for new ways to turn aluminum ore into metal. At the time, aluminum’s cost was comparable to that of silver. Initial attempts to produce the metal included passing an electrical current through an aluminum fluoride solution, which failed to produce enough Al to be viable. From there, tests began using molten fluoride salts, but it was difficult to get the salts sufficiently hot enough to produce large quantities of Al.
Charles Martin Hall eventually discovered that when adding a solution of cryolite (sodium aluminum fluoride), aluminum oxide dissolved at high temperature. By passing an electrical current through the solution for several hours, small amounts of aluminum were produced. Commercial production of aluminum metal was born.
Why is Aluminum Fluoride Added?
Cryolite solutions generally melt at about 1000°C. When AlF3 is added, electrolysis can happen in the cryolite solution at a temperature 40-60°C lower, drastically reducing the amount of energy needed to produce aluminum. In some studies, efficiencies of over 92% has been obtained in bench scale electrolysis of alumina in sodium fluoride.
Because of its electrolytic properties, aluminum fluoride has become one of the most commonly used compounds for the production of aluminum through molten salt baths. It is readily available commercially in various purities.
Noah Chemicals sells aluminum fluoride in both large and small quantities to institutions and organizations around the country. Contact our team of chemists today to discuss your need for AlF3.