Immobilization Mechanism of fluorine in Aqueous Solution from Road Material Containing Synthetic Hot Metal Pretreatment Slag by Shaking Test

摘要

The ability of immobilization of fluorine dissolved from the fluorine containing slag with the calcium compound was evaluated by the shaking test. In the calcium compounds which have the ability of immobilization of fluorine, the 12CaO centre dot 7Al_2O_3 was found to be the largest ability. From the results of evaluating the stability of immobilization with 12CaO centre dot 7Al_2O_3, it was shown that the dissolved fluorine from slag was immobilized for 100 h in shaking time. It was confirmed from the experimental results of X-ray analysis and the equilibrium thermodynamic calculation for aqueous solution that the generation of fluorite which was hard to dissolve in aqueous solution enabled the immobilization of fluorine dissolved from slag. Moreover, the 12CaO centre dot 7Al_2O_3 of 5-15 mass percent could be used for the road construction material which consisted of fluorine containing slag and blast furnace slag and as a result the immobilization of fluorine was confirmed.