FLUIDIZED-BED ROASTING OF SPHALERITE CONCENTRATES FROM ZAWAR.

Fluidization characteristics were determined for three different size fractions of sphalerite concentrates having average particle diameters of 0. 249, 0. 106 and 0. 093 mm. Roasting studies were carried out at four different temperatures, viz. 800, 850, 900 and 950 degree C. The values of activation energy, reported in the present work, compare very well with those of Formoso and Bryukvin. These values are high enough to propose a chemically controlled mechanism for the process, i. e. , the main rate controlling step is basically a chemical reaction at the mineral surface.