Investigation of Nigerian Kankara and Darazo Sediments as Synergistic Fillers in Fire Retardant Formulations

Abstract

n this work, two Nigerian sedimentary deposits were characterized for material properties using x-ray diffraction analysis, thermogravimetric analysis and scanning electron microscopy in order to determine their suitability as additives in fire-retardant formulations. Results indicated that Darazo contains 88% aragonite, a calcium carbonate-based mineral, while Kankara is a layered hydrous silicate with almost equal amount of kaolinite and molybdite. Both calcium carbonate and kaolin are popularly used in the fire-retardant industries as fillers in paints and plastics for flame retardation. Thermogravimetric analysis showed Darazo to be more thermally stable, decomposing at elevated temperature between 450 ^oC to 650 ^oC to release carbon dioxide. Its flame retardation will appear therefore more active at higher temperatures. Kankara clay appeared less thermally stable, releasing surface water at around 100-200 ^oC. Kankara therefore has the potentials to delay ignition. The hybrid formulation however created a synergy, enabling a longer active cooling range. The highest temperature reduction of 20.56% compared to the control was achieved in the hybrid formulation using Bunsen burner test. All the coated boards recorded lower percent mass losses compared to the uncoated wood. Therefore, both Darazo and Kankara sedimentary deposits have potential to serve as additives in fire retardant paints.