Fremgangsmåte og anordning for materialtesting ved anvendelse av differenstemperaturmålinger

A method and apparatus for timely and accurate measurement of material parameters are disclosed. A test sensor (30) measures the temperature of a sample of material as it is heated up and/or cooled down. A reference sensor (20) is used to obtain differential temperature measurements as the temperature of the test sample is varied. A differential temperature trace i s generated and analyzed in order to determine various characteristics of the material being tested. In one embodiment, the sodium fluoride to aluminum fluoride ratio (NaF:A1F3) and alumina concentration in a Hall bath aluminum smelting operation are determined in order to efficiently control smelting o f aluminum metal. In this embodiment, bath temperature and liquidus temperatur e may be measured and compared in order to determine the amount of superheat o f the bath and to prevent the operation of smelters at higher temperatures tha n necessary.