MINERAL PROCESSING AND EXTRACTIVE METALLURGY REVIEW, vol.29, no.1, pp.42-56, 2008 (SCI-Expanded)
Experiments were performed in aqueous hydrochloric acide (HCl)
solutions over the bulk solution pH
0.01 to 0.71 and at temperatures
of 25, 40, 50, 70, and 85C. Variation of the dissolution recoveries,
temperature, and pH with the time were studied. The
logarithms of the chemical dissolution rates (r) obtained at constant
hydrodynamic conditions for various temperatures and pH were
consistent with r
¼ k1aH
ş
,bulk
, where k1 stands for the chemical rate
constant and a
H
ş
,bulk
, designates the hydrogen ion activity in the
bulk solution. The overall dissolution rate constants were obtained
by plotting the R values calculated by using the (Ca
2ş, Mg2ş) concentrations
measured against the time. The overall dissolution rate
constant obtained was inconsistent with the corresponding rate constants
in the literature reported by Letterman (1995). The apparent
activation energy obtained over the temperatures 25 to 85C was
0.13 kJ
mol