Home >> Science & Nature >> Rocks & Minerals

Uses of Fluorite

Fluorite is a naturally occurring mineral consisting primarily of calcium fluoride, or CaF2. In its pure form, fluorite appears colorless with a glass-like texture. In most cases, however, it contains trace impurities that impart it with vivid colors ranging from yellow to red to blue. Despite its attractive appearance, jewelrysmiths avoid fluorite as a gemstone because it fractures easily. Fluorspar represents the ore form of fluorite and refiners sell fluorspar in three grades: acid grade, which contains at least 97 percent fluorite, ceramic grade, which contains 85 to 96 percent fluorite and metallurgical grade, which contains less than 85 percent fluorite.

Flux in Steel Making
- Chemically, steel is an alloy between iron and carbon. The conversion of iron ore into steel necessarily involves smelting the ore, along with coke, in a blast furnace. Refineries add a "flux" to iron ore and coke mixtures to lower the melting temperature. This lowers the operating temperature of the furnace, thereby reducing energy consumption and production costs. The flux also aids in the formation of the "slag" on the surface of the molten steel that contains most of the impurities.
Ceramics
- Fluorspar serves as an opacifying agent in the manufacture of flint glass, a special grade of glass used extensively in optics. Flint glass typically contains about 3 percent fluorite. Opaque enamels used to protect surfaces of appliances and fixtures contain between 3 and 10 percent fluorite by weight.
Hydrofluoric Acid and Its Derivatives
- Fluorite serves as one of the raw materials in the production of hydrofluoric acid and hydrofluoric acid production accounts for most of the fluorite consumed in the United States each year. Hydrofluoric acid, in turn, serves as a key component in the manufacture of numerous important compounds. The refining of aluminum from aluminum oxide, for example, involves the electrolysis of a mineral known as cryolite, which consists primarily of sodium aluminum fluoride. The world's sole source of natural cryolite was exhausted long ago, and hydrofluoric acid serves as one of the primary ingredients in the manufacture of synthetic cryolite. Hydrofluoric acid also serves as the precursor to fluorosilicic acid, the primary source of fluoride in municipal water supplies, and to sodium fluoride, the fluoride component in many toothpastes.
Specialty Applications
- Fluorspar finds a number of applications in specialty or "niche" markets that represent a small percentage of total fluorite consumption. Examples include welding rods and fluxes used in the manufacture of specialty metals, particularly certain grades of stainless steel with high chromium contents. Some sandpaper manufacturers use low-grade fluorspar as an abrasive.

Rocks & Minerals