Identification and estimation of carbonate minerals at low levels by evolved CO₂ analysis

Abstract

Recent differential thermal analysis (DTA) investigations of carbonate minerals using a flowing CO₂ furnace atmosphere^1,2 have shown that amounts as low as 0.25% (2,500 p.p.m.) may be detected in natural or synthetic mixtures, a significant improvement on that possible using static air DTA or conventional X-ray diffraction techniques. We show here that carbonate minerals can be routinely detected in the hundreds of p.p.m. concentration range using a non-dispersive IR CO₂ detector linked to a DTA furnace and describe modifications to the technique which permit the detection of certain carbonates below 100 p.p.m. The method described gives both an analytical determination of CO₂ and an identification of the mineral species responsible for CO₂ generation. It should be of use in the study of trace constituents in rocks, sediments, soils and ores and as a quality control technique in industrial processes.