Senior research chemist, Portland Cement Association, Skokie, Ill.
Director, Spectroscopic Laboratory of Erlin, Hime Associates, Northbrook, Ill.
A rapid and accurate atomic absorption method is described for the analysis of nine elements in portland cement and portland cement raw mix. These elements are aluminum, calcium, iron, magnesium, manganese, potassium, sodium, silicon, and strontium. Samples are fused with anhydrous lithium metaborate in a graphite crucible, and the molten melt is poured into a dilute acid solution.
Possible interferences and “matrix” effects are minimised by calibrating the instrument with standard solutions prepared from NBS standard cements.
Calcium and silicon determinations are made using a signal-averaging digital-readout device and a standard-unknown-standard bracketing technique,
The precision and accuracy for all of the elements determined is sufficient for control purposes.
The time required for the analysis of a single sample is approximately 1 1/2 h. When multiple samples are to be analyzed, time per sample is greatly reduced.
Paper ID: JTE10037J