||Chemistry of Fluoride Leaching and Associating Influential Factors in Plaster Board Waste
Sivasankar, VenkataramanOmine, Kiyoshi
56 , 2018-01 , 長崎大学大学院工学研究科
Plaster board waste generated from industries, usually contains major proportion of calcium as calcium sulfate. In addition, fluoride is remarkably one among the constituents of this waste material. Experimental studies were conducted to determine the fluoride leaching as a function of particle size, pH of leaching solvent (distilled water) and water: PBP ratio. The influence of sodium salts on the leaching of fluoride from PBP was studied. It was explored that one gram of plaster board waste contains 18.54 mg F per gram of PBP. High leaching of 3.70 mg F per liter was studied at pH 6.02 with Ca2+ and TDS contents of 1050 mg L-1 and 1640 mg L-1 respectively. The influence of fluoride leaching by sodium phosphate recorded a high value of 12.75 mg L-1 with no detectable amount of calcium ions. The leaching mechanism was predicted significantly by the exchange of Na+ and Ca2+ ions. The leaching rate as a consequence of shaking and stirring dynamics was also investigated at different conditions.