A bsorption and fixation of CO_2 to waste materials that contained Ca

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Fundamental research was carried out in order to develop the process in which CO_2 was absorbed and fixed to Ca containing waste materials, that is, waste torte, reduction and oxidation slag from electric arc furnace. In this study, those materials were wet and dry ground in CO_2 by a centrifugal ball mill and a vibration ball mil Effect of grinding conditions on the amount and the rate of CO_2 absorption was investigated. The main obtained results were summarized as follows;1) The wet grinding enabled Ca contained materials to more absorb CO_2 than the dry grinding.2) The amount and the initial rate of CO_2 of the reduction slag were the largest among them, and those of oxidation slag were second largest.3) The amount and the initial rate of CO_2 of those samples by the vibration ball mill were larger than those by the centrifugal ball mill.4) When the reduction slag was ground by the vibration ball mill, the absorption of CO_2 was determined by the widely defined interfacial reaction between CO_2 and the aqueous solution in the early stage of the experiment. In the latter stage of the experiment, the dissolution of the slag into water was rate controlling step. In the other experiments, the absorption of CO_2 was determined by the dissolution of the slag into water.5) The largest difference between the amount of CO_2 absorption on the reduction slag by wet grindings and that of emission of CO_2 in the grinding was 104mg(CO_2)/g(slag). This process will be able to attain one fifth of reduction target of CO_2 in iron and steel industry. Furthermore, it was revealed that the larger vibration mill and intermittent wet grinding were able to absorbed CO_2 more effectively