C. Arslan et G. Orhan, INVESTIGATION OF CHROME(VI) OXIDE PRODUCTION FROM CHROMITE CONCENTRATE BY ALKALI FUSION, International journal of mineral processing, 50(1-2), 1997, pp. 87-96
Citations number
9
Categorie Soggetti
Mineralogy,"Mining & Mineral Processing","Engineering, Chemical
The possibility of producing chrome(VI) oxide from domestic chromite c
oncentrates was investigated by carrying out laboratory-scale alkali f
usion and water leaching experiments. The effects of temperature, the
amount of NaOH added and the flow rate of air on chromium extraction e
fficiency in an alkali fusion step were investigated, Fusion product w
as leached with water to produce a clean Na2CrO4 solution. The paramet
ers of the water leaching experiments were the temperature and the sol
id/liquid ratio. The effect of purity of the monochromate solutions wa
s tested by producing dichromate both from impurities-containing and p
urified Na2CrO4 solutions. The purity of chrome(VI) oxides, prepared b
oth from monochromate with an impurity content and monochromate purifi
ed with CO2 were also examined. Kinetic investigations revealed that t
he fusion process can be described most adequately by a shrinking core
model for surface chemical reaction with an apparent activation energ
y of 43.5 kJ mol(-1), The results from leaching experiments, however,
suggested that the reaction rate is limited by the product layer mass-
transfer control. This analysis is supported by an apparent activation
energy of 10.5 kJ mol(-1).