Determination Of Main Components And Impurities In Lithium-boron Alloy

Lithium-boron alloy, first discovered by Frederick E. Wang, was found to be a good candidate as anode material for the thermal batteries. It has greater specific capacity, more negative potencial and greater specific power than the well-known anode materials. As the active element in the alloy, a good analytical procedure of lithium was put forward to be developed. The purpose of this study was to establish methods to dissolve LiB alloy and analyze the contents of major components and impurities.A variety of instrumental methods for accurate analysis of Li exists, like e.g. flame atomic emission spectrometry, atomic absorption spectroscopy and inductively coupled plasma-atomic emission spectrometry (ICP-AES), but they are not appropriate for samples of high content of lithium. Yet the most common methods for the determination of lithium concentration are gravimetric method and titration. Due to the chemical property study of lithium-boron alloy, an accurate analytical procedure of lithium by gravimetric method of Li2SO4has been developed and the determination range is between50%-80%. The dissolution procedures, volatilization of boron procedures and time of constant weight were discussed and the appropriate experiment conditions were established. We got the mass of impure Li2SO4after heating in the muffle furnace, and the content of lithium was calculated by minus the mass of impurities, which determinated by ICP-AES.The reliable method for analysis of high-content boron was mannitol acid-base titration. The dissolution methods, the effect of indicators, the melting time and the quantities of BaCO3were discussed and optimized. The recovery was between98%and102%and turned out to be reliable to meet the requirements of the testing for boron in Li-B alloys.To control and reduce the impurity content, it is very important to find a way to investigate the possibility of the direct and simultaneous measurement of impurity elements by ICP-AES. ICP-AES is attractive for trace analysis, owing to the satisfactory sensitivity coupled with the advantage of simultaneous determinations of several metals at several spectral lines. The effect of the matrix and acidity was examined. As lithium-boron alloy is a new production, there are not available standard referencematerials now. The recoveries of the analytes were measured at different concentrations using spiked solutions and used as an estimation of the accuracy of the method. The precision was evaluated by measuring the repeatability of the method for all analytes. The capability of the method as a routine analysis method was estimated through the determination of the detection limits of every metal studied.