The Separation of Trace Elements from Iron, and the Analysis of Iron-Rich Ores for Use as Reference Materials

摘要

Iron(III) chloride is separated from the trace elements in iron ores. After dissolution of the sample, the iron in 6M hydrochloric acid solution is separated, by liquid-liquid extraction with methyl isobutyl ketone, from the alkali metals, alkaline earth metals, lead(II), aluminium(III), titanium(IV), chromium(III), nickel(II), copper(II), cobalt(II), manganese(II), and zinc(II). After concentration of the aqueous phase by evaporation, the trace elements are measured by the use of atomic-absorption spectrophotometry or direct-reading spectrometry with excitation from an inductively coupled plasma source, or both. The separation procedure is rapid, resulting in reduction of the time required for analysis by the direct method, because only a limited number of dilutions are necessary, and the method of additions is not needed to compensate for interferences from the iron. The extractions of chromium(III), copper(II), nickel(II), strontium(II), rubidium(I), cobalt(II), manganese(II), zinc(II), barium(II), lead(II), aluminium(III), and titanium(IV) are at least 96 percent.