Kinetics of calcite overgrowth as a function of magnesium concentrations and spersaturation in artificial seawater

Abstract EN

The effects of different magnesium: calcium concentration and the degree of saturation in artificial seawater (ASW) upon the kinetics of carbonate solid overgrowth have been investigated.

It is shown that the mechanism of calcite overgrowth ؛s a surface-controlled (interface) reaction in the presence or absence of Mg2+ in ASW.

The reaction is a second order in Mg-free ASW and a third order in the presence of magnesium ion in the tested solution.

The rates of the overgrowth reaction decrease with the in-creased Mg2 ا concentration in ASW.

The decrease of reaction confirm the involvement of magnesium ions in overgrowth by magnesian calcite.

The reaction order, in presence of Mg2 ا tend to approach a second order at high degree of supersaturation and large surface area of calcite.