pigment-extender effect of umunze clay on screeding paint

The surface coating potentials of indigenous nigerian clay from umunze, orumba south local government area in anambra state were assessed in screeding paints as part of the effort to provide sustainable materials for the coating industries. the clay samples were washed, sedimented, dried, grinded, and sieved to 80 μm, and analyzed using energy dispersive x-ray fluorescence, x-ray diffraction spectrometry, and scanning electron microscope. the edxrf results shows a high percentage of nibioum (nb), silica oxide (sio2), and iron (iii) oxide (fe2o3) with 16.80%, 15.58%, and 6.60% respectively. other chemical components like lead (pb), barium (ba), zinc (zn), nickel (ni), and gallium (ga) were present in very small quantities in the clay gotten from umunze, meaning that the presence of these metals is too insignificant to cause damages to humans and the environment. meanwhile, xrd shows very high percentage of aluminum (al2) and silica (sio2) in umunze clay. this indicated that the crystalline structure of the uncalcined clay obtained from umunze is kaolinite, with chemical formula given as al2si2o9. the surface morphology presented the clay particles to be clogged, thus showing that the umunze clay is desired for multiple clay purposes. the formulated screeding paint from the calcined clay of 750 °c gave a better paint than the 450 °c via these physical properties of parameters mentioned below. the 750 °c calcined screeding paint has its refractive index determined at 2.71 (pl= 1.5-9), viscosity was determined at 2039.8 (pl= 2000-3000), and durability was determined at 70% (pl=68- 98 %) and thereby, making it a better substitution as paint pigment-extender than that of 450 °c calcined screeding paint. the work revealed a better temperature performance of the sample, such that the produced sample can withstand temperature up to 320 °c before it will start deforming. hence the clay can be used for ceramics.