Cadmium: Mode of Occurrence in Illinois Coals

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Science  20 Jul 1973:
Vol. 181, Issue 4096, pp. 264-266
DOI: 10.1126/science.181.4096.264


The cadmium content of 23 Illinois coals ranges from less than 0.3 to 28 parts per million. The higher cadmium contents are found in coals that also have a relatively high zinc content. Cadmium occurs in these coals in solid solution, replacing zinc in the mineral sphalerite (ZnS). The ratios of zinc to cadmium in sphalerites are similar to the ratios of zinc to cadmium in the whole coals from which the sphalerites were separated.