Lithium carbonate, formation purification

Lanthanum nitrate, analysis of anhydrous, 5 41 Lead (IV) acetate, 1 47 Lead(II) 0,0 -diethyl dithiophos-phate, 6 142 Lead (IV) oxide, 1 45 Lead(II) thiocyanate, 1 85 Lithium amide, 2 135 Lithium carbonate, formation of, from lithium hydroperoxide 1-hydrate, 5 3 purification of, 1 1 Lithium chloride, anhydrous, 6 154 Lithium hydroperoxide 1-hydrate, 5 1... 

Assuming a pK value of 2 to be the threshold for the carbonate-ion stability in molten salts in a C02-free atmosphere, it may be concluded that in halide melts consisting, even partially, of lithium salts and more acidic multivalent cations (Ca2+, Mg2+, Ln3+, etc.) carbonate ion is unstable and undergoes complete decomposition with the formation of the equivalent quantity of oxide ions in the melt. As for the other alkali metal halides studied, similar behaviour of CO2-ions can be expected only for CsCl, CsBr, and KBr melts at temperatures exceeding 800 °C. Of course, instability of carbonate ion in the melts does not mean an automatic disappearance of the oxygen admixture from the melt, since oxide ions arise instead of CO2- owing to their complete breakdown. This means that only for the melts characterized by a low pK value of the equilibrium (1.2.3), the carbohalogenation method of purification is the most suitable. 

The standard composition of an electrolyte in LlBs is a mixture of cycUc carbonates (such as ethylene carbonate (EC) and propylene carbonate (PC)) and chain carbonates (such as dimethyl carbonate (DMC), ethyl methyl carbonate (EMC abbreviated as MEC below), and diethyl carbonate (DEC)), to which about 1 mol/L of a lithium salt (such as lithium hexafluorophosphate (LiPF )) is added. Ube Industries, Ltd. discovered that if small amounts of impurities exist in the electrolyte, decomposition current generated from the impurities begins to flow, which leads to the formation of undesirable thick SET This spurred the development of a pioneering high-grade purification process for the base electrolyte in 1997 [16]. High purity is a key feature of functional electrolytes developed by Ube Industries, Ltd. and enables production of transparent and chemically stable electrolytes, in contrast to the conventional electrolytes which were less stable and brown owing to its low purity (Fig. 3.1). 

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