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Fluorite and various combinations of fluoride compounds can be made into synthetic crystals which have applications in lasers and special optics for UV and infrared. [38] Exposure tools for the semiconductor industry make use of fluorite optical elements for ultraviolet light at wavelengths of about 157 nanometers. Fluorite has a uniquely high ...
The patient receives a four-minute application of a high amount of fluoride. Varnishes, which can be more quickly applied, exist and perform a similar function. Fluoride is also often present in prescription and non-prescription mouthwashes and is a trace component of foods manufactured using fluoridated water supplies. [11]
The main uses of fluoride, in terms of volume, are in the production of cryolite, Na 3 AlF 6. It is used in aluminium smelting. Formerly, it was mined, but now it is derived from hydrogen fluoride. Fluorite is used on a large scale to separate slag in steel-making. Mined fluorite (CaF 2) is a commodity chemical used in steel-making.
Fluorite, the primary mineral source of fluorine, which gave the element its name, was first described in 1529; as it was added to metal ores to lower their melting points for smelting, the Latin verb fluo meaning ' to flow ' gave the mineral its name. Proposed as an element in 1810, fluorine proved difficult and dangerous to separate from its ...
price of food may account for some, but probably not all, of the increase in calories consumed as prices dropped. They propose a model of self-control based on hyperbolic discounting to explain why the increased availability of easy-to-consume snack foods has had a disproportionate effect on weight gain compared to other foods.
Two commercially important halide minerals are halite and fluorite. The former is a major source of sodium chloride, in parallel with sodium chloride extracted from sea water or brine wells. Fluorite is a major source of hydrogen fluoride , complementing the supply obtained as a byproduct of the production of fertilizer.
Hydrogen fluoride is typically produced by the reaction between sulfuric acid and pure grades of the mineral fluorite: [14] CaF 2 + H 2 SO 4 → 2 HF + CaSO 4. About 20% of manufactured HF is a byproduct of fertilizer production, which generates hexafluorosilicic acid. This acid can be degraded to release HF thermally and by hydrolysis: H 2 SiF ...
The fluoride minerals containing essential yttrium include tveitite-(Y) (Y,Na) 6 Ca 6 Ca 6 F 42 and gagarinite-(Y) NaCaY(F,Cl) 6. Sometimes mineral fluorite contains admixtures of yttrium. [ 1 ] [ 2 ]