Mineralogical, chemical and physico-mechanical properties of fired bricks for refractory industry applications

This study aims to characterize soils for their use in the refractory industry applications. Two types of hydromorphous soil were sampled in the locality of Minkoameyos in the neighbouring city of Yaoundé-Cameroon: multicolored soil clay (A001) and grey soil clay (A002). Mineralogical, chemical and physico-mechanical properties were investigated. Bricks made from these soils were heated at 900 °C, 1100 °C and 1200 °C temperatures. Physico-chemical properties showed that these soils are light (A002), silty (A001), inorganic and acidic, with pH values of 5.45 and 4.47 for A001 and A002, respectively. Chemical analysis revealed that these soils are essentially composed of silica (40 and 46%), alumina (35.9 and 32.5%) and coloring oxides (8.5 and 6.3%) for A001 and A002 samples, respectively. Mineralogical analyses of these soils revealed the presence of quartz, kaolinite, illite and muscovite. Bricks heated at 900 °C, 1100 °C and 1200 °C showed a variation in color from orange to reddish brown for A001 sample; from light orange yellow to dull orange for A002 sample and a sound ranging from dull to slightly metallic. Residual mechanical performance showed a slight drop in strength at the heating temperature of 900 °C (8.8 and 8.3 MPa for multicolored soil clay A001 and grey soil clay A002, respectively). This temperature seems sufficient for this type of floor. Above 900 °C, the impact of carbon is significant. These results showed that Minkoameyos hydromorphous soils clay have remarkable properties and can produce refractory materials.