ISSN 1017-2548(Print)
ISSN 2234-8530(Online)
Volume 11, Number 3
JKCSEZ 11(3)
June 20, 1967 

The direct acid leaching of domestic Marmatite concentrate at elevated temperatures and pressures was investigated. Almost 100 percent of zinc was extracted from the concentrate liberating free sulfur in 4 hours at 100℃ when the oxygen partial pressure was 5 atm. in sulfuric acid solution. By applying the Arrhenius equation to leach reaction in the range of 60° to 100℃ at the same oxygen partial pressure, 15.7 kcal per mole of activation energy was calculated. At the initial stage of leaching, the rate of reaction increased linearly by increasing temperature and pressure. The concentration of sulfuric acid gave minor effect to leaching velocity in the range of 5 to 20 percent. The particle size should be under 270 mesh for 100 percent extraction of zinc.