第二鉄イオンによる黄鉄鉱の溶解速度
1987 年 103 巻 1192 号 p. 395-400
詳細
1987 年 103 巻 1192 号 p. 395-400
A Kinetic study of pyrite oxidation by ferric sulfate in absence of oxygen and bacteria is described. The effects of reactor agitation, ferric, ferrous and hydrogen ion concentration and reaction temperature on the oxidation rate were examined. All experiments were carried out isothermally in a well-stirred batch reactor. The kinetic data were used to develop kinetic rate equations. The results are summarized below.
Pyrite oxidation is decribed by following two reactions occuring in succession.(1) Ferric ions react with FeS2 to form ferrous ions and a sulfur product.(2) The elemental sulfur is oxidized to sulfate by ferric ions. Kinetic rate equations were obtained for the two reactions, (1) and (2), respectively.
The oxidation rate of the reaction (1) was found to be independent of pH. On the other hand, that of the reaction (2) increased with increasing pH. So sulfate is formed more than elemental sulfur with increasing pH.
The activation energies for reactions (1) and (2) were 47KJ/mol and 83KJ/mol, respectively. Because of the difference between the activation energies, sulfate is formed more than elemental sulfur with an increase in temperature.
