Lithium fluoride flux

The most popular and elegant specimen preparation technique introduced by Claisse 17] is based on fusion of solid specimens with lithium tetraborate. The method was used with great success in our laboratory for the rapid quantitative X-ray fluorescence analysis of silicates, bricks, refractories, limes, iron, and manganese ores. The use of lithium tetraborate and lithium fluoride flux systems was therefore examined first. 

Aluminum fluoride Lithium fluoride flux, hard solder Potassium fluoride flux, magnesium prod. 

Uses. Lithium fluoride is used primarily in the ceramic industry to reduce firing temperatures and improve resistance to thermal shock, abrasion, and acid attack (see Ceramics). Another use of LiF is in flux compositions with other fluorides, chlorides, and borates for metal joining (17) (see Solders). 

Lithium Fluoride (Li + F —> LiF) is used to produce ceramics and rocket fuel and is used as welding and soldering flux and in hght-sensitive scientific instruments (e.g., X-ray diffraction, which is the scattering of X-rays by crystals that produce a specific pattern of that crystal s atoms, thus producing a technique for identifying different elements). 

The important uses of lithium fluoride are as flux in glasses, vitreous enamels and glazes in soldering and welding aluminum and its prisms in infrared spectrophotometers. The compound also is used for storing solar energy. 

Lithium fluoride. CAS 7789-24-4. LiF, mp 848 C, soluble in HyO tslighl I Used in enamel and glass formulations as a component of w elding and brazing fluxes in the eiectrowinning of aluminum and as an ingredient of molten salts. 

The primary use of lithium fluoride is in the ceramic industry. It reduces the firing temperature and improves the resistance to abrasion, acid attack and thermal shocks. It is essential component of the fluorine cell electrolyte. An addition of small amount (1-1.5%) to KHF2 HF electrolyte improves the wettability of the carbon anodes and lowers the tendency of the cell to polarize. Another important use of LiF is in flux compositions containing chlorides, borates and other fluorides. Lithium fluoride windows made from high purity crystals are used for X-ray monochromators, UV, visible or IR regions [18]. 

A small amount, 2.5 to 3.0 g of representative gypsum specimen, was calcined for 1 h at 1000°C in a platinum crucible, and the loss on ignition was recorded. A portion of 1.0000 g of the calcined specimen was mixed with 6.000 g of dense lithium tetraborate (Spectroflux 100 , Johnson and Matthey Co.) and 0.3000 g of lithium fluoride. Approximately 3 mg of lithium bromide was added to the mixture as a release (nonsticking) agent. Fusions were carried out on a propane flame, using a Claisse fluxer (2] equipped with crucibles and molds made from 95% platinum-5% gold alloy. The volume of molten flux was adequate to fill the 32-mm diameter mold to a sufficient height and produce a disk approximately 4 mm thick. 

The advantages of using sodium tetraborate for the fusions outweigh the loss of sodium as an analyzed element. Times required for the fusion and swirling of the flux on flame (Table 1) were quite short. The use of lithium fluoride and lithium bromide was eliminated completely. The disks prepared from sodium tetraborate release easily from the molds each time, without any sign of sticking, cracking, or crystallization. 

When lithium tetraborate and lithium fluoride are used as a flux, or when... 

Boric acid Copper oxide (ic) Lithium chloride Lithium fluoride Potassium tetraborate Tributyl borate Zirconium potassium hexafluoride welding flux, gaseous Trimethyl borate welding fluxes, special Zirconium welding gas Oxygen... 

Several complementary pairs of activators have been used, but the most effective are those consisting of cerium-samarium and europium-samarium, the samarium ions furnishing the trapping centers. Phosphors of this type are best prepared from the pure alkaline earth sulfides or selenides by introducing the activators wdth the aid of a flux such as an alkaline earth halide or lithium fluoride. 

Lithium fluoride (1944) n. LiF. A crystalline salt used in making prisms and ceramics and as a flux. 

Lithium fluoride is used as a flux when welding or soldering aluminum. How many grams of lithium are in 1.00 lb (454 g) of lithium fluoride ... 

Welding flux comprises equimolar mixtures of lithium chloride and potassium chloride with an addition of lithium fluoride, sodium fluoride, potassium fluoride or... 

Lithium Halides. Lithium haHde stabiHty decreases with increasing atomic weight of the halogen atom. Hence, the solubiHty increases from the sparingly soluble Hthium fluoride to the very soluble bromide and iodide salts. The low melting points of Hthium haHdes are advantageous for fluxes in many appHcations. 

Poetschke (1925) patented a dental silicate powder prepared by fusing zinc silicate with calcium fluoride. This is a kind of silicophosphate cement (Section 6.6). Thomsen (1931) attempted to formulate a water-setting dental cement. Heynemann (1931) included lithium salts in the flux and Brill (1935) included them in the liquid. 

SAFETY PROFILE Poison by ingestion and subcutaneous routes. When heated to decomposition it emits toxic fumes of F". Used as a flux in enamels, glasses, glazes, and welding. See also FLUORIDES and LITHIUM COMPOUNDS. 

Complete localization is, of course, possible only for an isolated system. What is remarkable, however, is the extent to which the electrons of atoms in an ionic molecule approach this limit of perfect localization, with /(fi) values in excess of 95 per cent not being uncommon. In systems, such as the fluorides and chlorides of lithium and sodium displayed in Fig. E7.2, the atomic surface of zero flux is found to minimize the fluctuation in the atomic populations and, thus, the magnitude of the correlation hole per particle is an extremum for such atoms. The properties of the number and pair densities for these... 

Fused salt solutions may be found in which the solubility of these oxides is appreciable at high temperatures and from which crystals grow as the solution is cooled. Some of the fluxes which have been used for growth of the oxides of concern here are (a) potassium nitrate-sodium nitrate, (b) lead fluoride-bismuth oxide, (c) lead oxide-bismuth oxide, and (d) lithium hydroxide-boric acid-molybdenum oxide. Temperatures frequently are in the range of 1300°C. 

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