The Removal of Fluoride Ions from Wastewater Produced During Uranium Recovery in Three Groups of Uranium Conversion Factory Scraps Using Chemical Precipitation Method

In the present research work, high concentration amounts of fluoride ions in nuclear waste produced during uranium recovery from the three groups of uranium conversion factory scraps (C36, C37, 56P) were removed by the chemical precipitation method. In this method, calcium chloride due to its high solubility in water and lower sludge production in comparison with other compounds of calcium was used as a precipitant agent. The effects of different parameters such as: the type and concentration of coagulant, pH, the concentration ratio of calcium to fluoride, time and rate of stirrer, aging time and the temperature of precipitation on the removal of fluoride were optimized. The results show that the yield of fluoride removal in these samples relates to all of these parameters with the exception of temperature. In spite of the theoretical calculations, the amount of fluoride in final wastewater for C36, C37, 56P decreases to 3.6, 5.8 and 4.6 ppm, respectively, which can be released to the environment directly at a slight dilution. The results show that calcium chloride in the optimized conditions, is a suitable precipitant agent for the effective decrease of high concentration of fluoride in the real sample. Also, the performed experiment, by using the industrial grade calcium chloride product, shows the similar result which confirms the possibility of this method being used in industry.