抄録
The wastewater containing fluoride is usually treated by the coaguration and sedimentation method using calcium hydroxide, with the resultant sludge being dischaged as industrial waste. Because of the shortage of landfill place, the reduction of such the industrial waste sludge is now an essential issue in the wastewater treatment.
The author have recently succeeded in practical application of fluoride regeneration to calcium floride using granular calcium carbonate. So far three full-scale industrial treatment plants have been under operational.
In this technology, wastewater is fed to the reactor with granular calcium carbonate, which remove fluoride from the wastewater and converted them to granular calcium fluoride which purity can be compared to natural fluorite.
In this study, the author analyzed kinetifically the reaction rate by applying the unreacted shrinking core model. It was found that the rate of reaction is contorolled by chemical reaction on the interface between the reactant cell phase and the unreacted core. Moreover, the author carried out a simulation analysis based on a fluoride regeneration pilotplant test data, and the results were in good agreement with the actual measured values.
