Kinetic Laws of the Dissolution of Alunite from Alunite Ores with an Alkali Solution

Abstract The leaching of the major mineral (potassium alunite) from alunite ores with a potassium hydroxide solution is studied. The process occurs with the retention of other minerals (dickite, hematite, quartz) in the leaching residues. The kinetics of leaching of potassium alunite from alunite raw materials is studied by the powder dissolution method in the temperature range of a potassium hydroxide solution 333–368 K at a KOH concentration of 52.96–243.8 g/L. The activation energy of the process is calculated using the experimental results obtained (Ea = 73.14 kJ/mol). The calculated energy indicates that the leaching of alunite from alunite ores is controlled by a surface chemical reaction, and the reaction order with respect to KOH is 1.02. The process under study is described by a first-order kinetic equation.