The influence of chloride and sulphate ions on the slaking rate of lime derived from different limestone deposits in South Africa

Abstract

This paper describes an investigation into the influence of chloride and sulphate ions on the slaking of lime prepared from limestones of different geological origin in South Africa. It was endeavoured to assess the effects of the presence of chloride and sulphate ions on the hydration rate of lime, compared to its slaking in pure water. It was found that the rate of hydration is slightly retarded in the presence of a high concentration of chloride ions, while sulphate ions retard the slaking of lime significantly. This investigation indicated that impurities present in the original limestone, as well as those commonly found in water used for slaking purposes, may exert an influence on the hydration behaviour of lime.