An empirical study of factors influencing lime slaking. Part II: lime constituents and water composition

Abstract

Chloride, carbonate and sulphate ions are common constituents of many waters and are often found in high concentrations in water used for the slaking of lime. Furthermore, magnesium oxide is a common constituent of many limestones and can, after calcining, also affect the hydration rate of the lime if it is present as magnesium oxide. The purpose of this investigation was to assess quantitatively the effect of these various chemical influences, whether it be from a geological origin or present in the slaking water, on the slaking rate of lime. It was found that the presence of chloride ions in the slaking water increased the lime reactivity, while sulphate and carbonate ions in the slaking water retarded the hydration reaction. Magnesium oxide also had a detrimental effect on the slaking rate of lime.


Keywords: Lime, Slaking, Chloride, Sulphate, Carbonate


(WaterSA: 2003 29(2): 157-160)