Kinetic modeling of the decomposition of beudantite in NaOH medium

This piece of work presents a study on the reaction of beudantite in NaOH medium under a wide range of experimental conditions. The partial decomposition of solids indicates the presence of an unreacted beudantite core, a reaction front and a halo of amorphous decomposition gel made of iron hydroxides and lead, through which sulfate and arsenate ions diffuse from the beudantite into the medium, while hydroxide ions from the medium diffuse through the gel onto the core of spherical particles of beudantite. We studied the dependence of the reaction rate on (OH −1 ) concentration, temperature and particle size in order to determine the reaction order and activation energy of the decomposition process of beudantite. A comparative study on the experimental rate constants of the alkaline decomposition of beudantite and other arsenic jarosites was conducted.