The use of high speed detectors turned X-ray diffraction (XRD) into an important tool for quality and process control in mining industries, especially in the sector of heavy mineral concentration and processing. Next to the information about the composition of a raw ore, heavy mineral concentrate or titania slag it provides useful information by the quantitative determination of the crystalline phases and the amorphous content. The analysis of the phases can help to optimize the concentration of ores and reduction of ilmenite concentrate. Traditionally quality control of heavy mineral concentrates and titania slag relies mainly on elemental, chemical, gravimetrical and magnetic analysis. Since the efficiency of concentration and reduction depends on the content of the different titanium and iron phases, such as ilmenite FeTiO3, rutile TiO2, anatase TiO2 or the various titanium oxides with different oxidation stages, a fast and direct analysis of the phases is required.The three case studies of this paper demonstrate how XRD and cluster analysis can be used for process optimization and quality control. The potential of XRD as an automatable, reliable tool, useful in the characterization of heavy mineral concentrates and titania slag will be demonstrated.