The Impact of Fine Sand Calcined at 450°C and 750°C on Textcoat and Emulsion Paints, Respectively

This study investigated the suitability of Nawgu clay as an alternative pigment extender in emulsion paint production. Clay collected from Ifiteora Village, Nawgu, Anambra State, Nigeria, was washed, dried, pulverized, sieved, and separately calcined at 450°C and 750°C for 2–3 hours. The raw clay was characterized using X-ray fluorescence and X-ray diffraction analyses, while the formulated paints were evaluated through physicochemical and quality-control tests. XRF analysis showed that the clay contained predominantly silica (49.79%), alumina (14.04%), and iron (III) oxide (6.21%), while XRD confirmed the presence of quartz and kaolinite. Two emulsion paint samples were produced using the calcined clays as extenders and compared with a commercial control paint. The 450°C and 750°C formulations recorded moisture contents of 61.735% and 70.862%, ash contents of 28.998% and 21.850%, viscosities of 26.256 and 8.844 centistokes, pH values of 9.55 and 10.27, and specific gravities of 1.080 and 1.226, respectively. The 450°C formulation demonstrated superior performance to the 750°C sample, particularly in viscosity and moisture retention, although the commercial control exhibited better overall properties. The findings indicate that Nawgu clay has potential as a low-cost, locally available extender, but cannot yet completely replace conventional industrial extenders without further improvement in formulation and processing.