Abstract
Usually Gakushin method is used for rapid analysis for determination of total FeO in acid slag. But it is not fit for a rapid method, because its procedure to fuse sample in a nickel crucible is very inconvenient.
Therefore the authors made a study on the direct dissolution by acid, and this extremely simple procedure was found to give satisfactory results. In order to investigate the accuracy of this improved method, the authors compared it with other various methods. As result of this investigation, it was observed that values obtained by a Mitsubishi method are slightly higher or lower than the standard value according with kinds of slag, though the results of Gakushin and a Muroran method agree each other.
Concerning this matter, the authors again studied on all kinds of acid slag and came to the following conclusion.
(1) Gakushin and Muroran methods give total FeO value, while Mitsubishi method gives active (free) FeO value, (2) so that the total FeO value must always give the lower figures when slag containing FeIII is determined by the latter. (3) The cause of high value is due to the existence of CrII and it was known from results of this study that the percentage of CrII in chromium acid slag is about 30% of total Cr.
