Background: Being by-products of non-ferrous metallurgy, slags contain fayalite
(Fe2SiO4) as the major component. Since hydrometallurgical methods are considered as
the most promising for processing such material to obtain valuable metals, increasing the
leachability of fayalite in sulfuric acid as a widely used leaching agent is an important task.
Objective: The present work was devoted to increasing the reactivity of fayalite by using
Method: Fayalite, synthesized with the use of powders of metallic Fe, Fe2O3, and SiO2,
was subjected to mechanical activation in the planetary ball mill at 400 rpm with a
ball/powder ratio of 5 for 45 minutes. Then, activated and non-activated fayalite samples
were subjected to sulfuric acid leaching. Before leaching, solid samples were characterized
by XRD and Dynamic Light Scattering (DLS). Quantitative analysis of Fe and Si in the
leachate was determined by Inductively Coupled Plasma-Atomic Emission Spectroscopy.
Results: Mechanical activation led to partial amorphization of the initial fayalite sample. It
was found that the leaching rate constants of the treated samples in sulfuric acid solution
(50-80 g×L-1) at 298, 338, and 368 K increased and the activation energy of the leaching
process decreased, i.e. mechanical activation enhances the reactivity of fayalite in H2SO4
Conclusion: Mechanical activation can be applied to improve fayalite leachability in sulfuric
acid solution. The results obtained can be used in the development of methods for
leaching slag of non-ferrous metallurgy, in particular, copper smelter slags, the major
component of which is fayalite.