Kinetic study of the isothermal and non-isothermal chlorination of a scheelite–wolframite concentrate with chlorine and sulphur dioxide

• Published in: Thermochimica acta 1999-10, Vol.338 (1), p.103-112
• Main Authors: Menéndez, C.J., Tavani, E.L., Nolasco, E.J.
• Format: Article
• Language: English
• Subjects: Applied sciences; Chlorination; Exact sciences and technology; Isothermal; Kinetics; Metals. Metallurgy; Non-isothermal; Production of metals; Production of non ferrous metals. Process materials; Pyrometallurgy; Scheelite; Wolframite
• ISSN: 0040-6031; 1872-762X
• DOI: 10.1016/S0040-6031(99)00204-X

The isothermal and non-isothermal chlorination of a scheelite–wolframite concentrate with chlorine and sulphur dioxide was studied. Tests were made in a vertical reactor with a static bed and upward flow of reactive gases. The behaviour of the chlorination was analyzed from the identification of the volatile and non-volatile reaction products obtained in each case. The main identified reaction products were WO 2Cl 2, FeCl 2, FeCl 3, S 2, FeS, CaSO 4 and CaCl 2. Taking into account the most important physicochemical characteristics of the system, an empirical methodology to make chlorinations was proposed. The validity of the empirical methodology that we used was demonstrated utilizing data obtained under isothermal and non-isothermal conditions. Experimental results showed that the presence of non-volatile reaction products affects the chlorination under isothermal and non-isothermal conditions. A same kinetic dependence was found with both methods. Finally, the apparent activation energy and the rate constant of the reaction were determined through isothermal and non-isothermal methods.