Fluoride LiF

The optimal temperature range for the fluorination process was found to be about 230-290°C. The resulting cake was leached with water. The prepared solution was separated from the precipitate by regular filtration and the separated insoluble precipitate was identified as lithium fluoride, LiF. The solution contained up to 90 g/1 Ta205. Solution acidity was relatively low, with a typical pH = 3-4, and was suitable for the precipitation of potassium heptafluorotantalate, K2TaF7, tantalum hydroxide or further purification by liquid-liquid extraction after appropriate adjustment of the solution acidity [113]. 

Using Lewis symbols, write a balanced chemical equation showing the formation of lithium fluoride, LiF, from isolated lithium and fluorine atoms. 

Polarized Raman spectra from the alkali fluorides LiF, NaF and CsF habe been observed with argon laser excitations by Evans and Fitchen 09). These spectra are of interest as an extreme test of lattice dynamics theories and polarizability models. 

Super-rate burning occurs when lithium fluoride (LiF) is incorporated into NC-NG or NC-TMETN double-base propellants. As shown in Fig. 6.27, the burning rate of a propellant catalyzed with 2.4% LiF and 0.1% C increases drastically in the pressure region between 0.3 MPa and 0.5 MPa. This super-rate burning effect diminishes gradually as the pressure is increased above 0.5 MPa. The non-cata-lyzed propellant is a conventional NC-NG double-base propellant composed of 55 % NC, 35% NG, and 10% DEP. The maximum burning rate increase is about 230% at 0.5 MPa. 

In order to avoid the use of lead compounds on environmental grounds, lithium fluoride (liF) has been chosen to obtain super-rate burning of nitramine composite propellants.P7281 Typical chemical compositions of HMX composite propellants-with and without liF are shown in Table 7.4. The non-catalyzed HMX propellant is used as a reference pyrolant to evaluate the effect of super-rate burning. The HMX particles are of finely divided, crystalline (3-HMX with a bimodal size distribution. Hydroxy-terminated polyether (HTPE) is used as a binder, the OH groups of which are cured with isophorone diisocyanate. The chemical properties of the HTPE binder are summarized in Table 7.5. 

Lithium Tantalum Fluoride, LiF.TaFg.2HaO or LiTaF6.2HaO, is obtained in colourless, prismatic crystals when a solution of tantalum pentoxide in excess of hydrofluoric acid is treated with lithium carbonate.4... 

Lithium carbonate (Li2C03), the most widely used of the compounds, is employed in the production of lithium metal and frits and enamels. Together with lithium fluoride (LiF), it serves as an additive for cryolite in the electrolytic pot line production of primary aluminum. 

Ammonium fluoride solution a white, gelatinous precipitate of lithium fluoride, LiF, is slowly formed in ammoniacal solution (distinction from sodium and potassium). 

The alkali metal fluorides, LiF, NaF, KF, CsF, and RbF are made by the action of hydroxide or carbonate on hydrofluoric acid. These are very important compounds and are produced in several hundred ton quantities. 

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