Metallurgy dusts as a pigment for glazes and engobes

This study is focused on using the dust from metallurgy as a pigment. The agglomerating dust is formed during metallurgical processes. This waste product is interesting for recycling process. The main mineralogical phase of dust is hematite α-Fe2O3. Both synthetic and natural iron oxides are commonly used as pigments in ceramic industry. In this experiment the metallurgy dusts were used as a pigment for preparation of glazes and engobes. Agglomerating dusts were used both precalcined thermally at 700 °C and 900 °C and in an original state. The prepared glazes were composed of a transparent glaze base with 10 wt% agglomerating dusts as pigment. The glazes calcined at 1060 °C were finally yellow colored and glazes calcined at 900 °C were brown colored. Engobes contained a ceramic clay base with 1, 5, 10 and 50 wt% of dust as pigment. Engobes calcined at 900 °C were red and grey colored. The pigments were characterized by X-ray diffraction (XRD), chemical (XRFS) analysis, granulometry (PSD), thermogravimetric (TG) and differential thermal (DTA) analysis, scanning electron microscopy (SEM) and CIELab values.