Dissolution kinetics of potassium from glauconitic sandstone in acid lixiviant

Laboratory studies have been conducted for dissolution of potassium from glauconitic sandstone in diluted hydrochloric acid, nitric acid and sulphuric acid at different temperatures. The dissolution of potassium was analysed with different kinetic models. The dissolution of potassium follows a mixed control model embodying chemical control model at the initial stages of dissolution and diffusion control model at the later stages of dissolution for all the three lixiviants. The activation energy for dissolution of potassium in hydrochloric acid varies from 79.03 to 99.41 kJ/mol, whereas in nitric acid and sulphuric acid, it varies from 56.93 to 95.18 and 37.43 to 56.24 kJ/mol, respectively. (C) 2000 Elsevier Science B.V. All rights reserved.