Surfactant separation as a technique for physical and chemical characterization of ore processing residues

When characterizing multi-phase materials, several authors have recommended separating the material into various fractions consisting of a reduced number of minerals. However, the common separation techniques are of limited value when treating ultra-fine-grained materials. We present in this paper a separation technique using tensio-active solutions which break up any particle agglomerates which may be present and facilitates sedimentation of component particles according to grain size. These fractions have a distinctive mineralogy and chemistry. The technique has been applied to two selected samples from two mining residue sites in Germany. Results from Bielatal, a tin residue, show that a large proportion of the arsenic and heavy metals are concentrated in a suspension fraction, which consists of clay minerals and amorphous iron oxyhydroxides. Silicates such as a micas and feldspar settle out quite rapidly, whereas, other minerals, such as hematite take longer. In the case of D¨ankritz, a uranium mine waste, the same technique was applied and similar results were obtained for the heavy metals distribution. Additional study indicated that radium is with barite and other radio-isotopes were associated with the fine suspension fraction.