ABSTRACT
The possibility of preparation of operating rechargeable liquid battery cells based on aluminium and its alloys is systematically checked. In all cases we started from aluminium as the negative electrode whereas as the positive electrode three different metals were tested: Pb, Bi and Sn. Two types of electrolytes were selected: Na(3)AlF(6) -AlF(3) - BaCl(2) - NaCl and Li(3)AlF(3) - BaF(2). We show that some of these combinations allowed efficient separation of individual liquid layers. The cells exhibited expected voltages, relatively high current densities and could be charged and discharged several times. The capacities were relatively low (120 mAh in the case of Al-Pb system), mostly due to unoptimised cell construction. Improvements in various directions are possible, especially by hermetically sealing the cells thus preventing salt evaporation. Similarly, solubility of aluminium in alloys can be increased by optimising the composition of positive electrode.
ABSTRACT
As the world's capacity for aluminium production increases, the amount of waste connected with this industry is also increasing. Spent potlining (SPL) from aluminium reduction cell cathodes presents a major environmental concern in the primary aluminium industry. It is concluded, after laboratory tests, that leachable cyanide and fluoride compounds present the major problem in SPL disposal. The behaviour of cyanide and fluoride under high temperature treatment has been investigated. On the basis of this laboratory investigation, the possibilities for SPL utilisation in red brick manufacturing, cement industry and thermal power stations were evaluated. SPL refractory material is already re-used in red brick manufacturing. In the cement industry, a pilot test on the utilisation of 25 t SPL carbon waste mixed with green petrol coke gave positive results. Additionally a fluoride emission forecast for a thermal power station utilising carbon waste SPL mixed with coal was elaborated.
