Magnesium Ion Inhibition of Calcium Carbonate Precipitation and its Relation to Water Quality

The effect of Mg++ ion on the solubility of calcium carbonate was determined using P. K. Weyls carbonate saturometer. The amount of calcium carbonate precipitated or dissolved was measured for five series of waters when equilibrated with solid carbonate. It was found that the effect of Mg++ ion on solubility depend upon the nature of the solid phase: surface area, coprecipitated Mg++, minerology, etc. Pure low area calcite showed an increase in solubility which could be explained by ion-pair formation, while its other carbonates departed from this behavior