Sample contamination by grinding

The extent of contamination resulting from the use of hardened high-carbon steel grinding plates, a chrome-steel shatterbox, a tungsten carbide shatterbox, an agate mortar and a corundum-ceramic handmill was evaluated on samples of Ottawa Sand Standard (>DVo SiO). These samples, after preparation in each of the different types of equipment, were analyzed for twenty-one major, minor and trace elements by X-ray-fluorescence methods and for five rare-earth elements by flameless atomic absorption. Semiquantitative results show that the agate mortar produced no measurable contamination. Other materials contributed the following: corundum-ceramic contaminated the samples with Al, Mg, Ba, Cu, Zn and Cr; tungsten carbide, with Co, M and W; chrome steel, with Fe, Cr and Mn; and hardened high-carbon steel, with Fe, Cr, Zn, Mn, Cu and Ni.