Fluorspar is an industrial mineral from which the element Fluorine is liberated, with two major downstream uses; the production of Hydrofluoric Acid (HF) which is used as a building block for Fluorine Chemicals, and the production of Aluminium Fluoride (AlF3) which is an important additive for the production of Aluminium by electrolysis. Fluorspar also finds application in various steel and aluminum products, glass and ceramic manufacturing and in the growing nitrogen trifluoride (NF3) sector. Examples of products containing Fluorine includes household and automotive air conditioners, Teflon products fluoxetine medicines, welding rods, glass and ceramics.
Fluorspar is the commercial name for the mineral fluorite, CaF2. In its pure form it consists of 51.1% calcium (Ca) and 48.9% fluorine (F). In nature however, small amounts of silicon, aluminum and magnesium are usually present due to impurities. Fluorspar is found in a wide range of geological environments; however, it most commonly occurs as vein fillings in rocks that have been subjected to hydrothermal activity. These veins often contain metallic ores which can include sulfides of tin, silver, zinc, copper and other metals. Commercial fluorspar is graded in accordance to its quality. The grades depend on the content of fluorspar and the associated amounts of impurities (calcite, quartz, Sulphur, arsenic and lead). The grades are:
- Acid grade – contains a minimum of 97% of fluorspar, with the remaining 3% being various impurities
- Ceramic grade – contains 85% – 96% fluorspar, with the remaining 4% – 15% being various impurities
- Metallurgical grade – contains between 60% and 84% of fluorspar, with the remaining 16% to 40% being various impurities
The grade of fluorspar determines its end-use. Almost two thirds of all fluorspar is of acid grade and is predominantly used in the production of hydrofluoric acid (HF), while approximately one third of fluorspar is of metallurgical grade and primarily used as a flux in steelmaking and in the production of aluminum. A small amount of fluorspar is of ceramic grade, where it is used in the manufacture of specialty glass, ceramics and enamelware. HF is a highly corrosive acid, capable of dissolving glass and many other materials, primarily oxides. Due to its highly corrosive characteristic, it is used in many industries, such as chemical, mining, refining, glass finishing, silicon chip manufacturing and cleaning. Approximately 60 % of global HF production is used in various fluorochemical applications, such as refrigerants, non-stick coatings, medical propellants and an aesthetics, whereas smaller amounts of HF are used in petroleum alkylation, and as a pickling agent for metal etching in the electronics industry. Furthermore, HF is also used for cleaning of silicon wafers, glass etching and in the production of polished and frosted glass.