An Experimental Determination of the Incorporation of Trace Metals into Calcite (thesis)

Abstract

A new experimental method to synthesize calcite crystals via aqueous slow diffusion was used to examine the level of incorporation of six different trace metal (Co, Mn, Pb, Hg, As, Se) contaminants in calcite. The aqueous reagent solutions had a constant pH and calcium concentrations and varied only in the concentrations of the trace metal contaminants. The experiments resulted in euhedral rhombohedral calcite crystals in the 100 µM range and up to 500 µM across. ICP-OES analysis of the trace metal solutions before and after the calcite precipitation indicated a large decrease in cobalt and manganese abundance at all trace metal concentrations, and in lead in the part-per-million concentrations; a modest decrease in the abundance of lead at low concentrations and mercury at high concentrations; and a small decrease in the abundance of selenium at all concentrations and mercury at low concentrations.