Crystallization Control in Metallurgical Slags Using the Single Hot Thermocouple Technique

Autor: René Hagemann, Antonio Cezar Faria Vilela, Piotr R. Scheller, Jeferson Leandro Klug, Nestor Cezar Heck, Hans P. Heller
Rok vydání: 2012
Předmět:
Zdroj: steel research international. 84:344-351
ISSN: 1611-3683
DOI: 10.1002/srin.201200093
Popis: With the single hot thermocouple technique (SHTT) the solidification behavior of metallurgical slags has been studied by in situ observation, constructing time– temperature–transformation (TTT) or continuous-cooling-transformation (CCT) diagrams. The SHTT is a unique apparatus that enables measurement of the slag sample temperature using a thermocouple while the sample is heated or cooled simultaneously. Due to the low heat capacity of the system sample/thermocouple high heating or cooling rates can be easily obtained (>30008C/min). The following findings are reported in the present paper: (i) For the CaO–Al2O3 slag – 44% CaO, 56% Al2O3 (wt%) – the CCT diagram shows large differences between liquidus and the temperature for first crystals precipitation, even at low cooling rates, for example, 1688C below the liquidus when cooling at a rate of 68Cmin � 1 . (ii) For the CaO–SiO2 slag – % CaO/% SiO2 (wt%) ¼0.7 – no crystal is observed for continuous cooling, even at low cooling rates, such as 108Cmin � 1 . During isothermal experiments crystallization was observed only at 10008C with an incubation time of 76s (average of six experiments, standard deviation 27s). However, crystallization becomes much more intense for the CaO–SiO2 slag when increasing the temperature after reaching lower temperatures (
Databáze: OpenAIRE
Externí odkaz: