鉄鉱石中の鉄分の蛍光X線分析における結合水および鉄(II)の影響

抄録

In X-ray fluorescence analysis of total iron (T. Fe) content in iron ore by the glass bead technique, the determination value of T.Fe content is influenced by coexistent impurities in iron ore, the loss of bound water, and the gain of oxygen in glass bead preparation. In this study, the phenomena of the loss of combined water, the gain of oxygen on ignition, and the influence of these phenomena on the analysis of T.Fe content have been investigated. The results were as follows: (1) It was experimentally confirmed that the bound water escaped from the glass bead and an iron metal was converted from a lower to a higher oxidation state, Fe(II) →Fe(III), in glass bead preparation. (2) The phenomena of (1) have an influence on FeK_α intensities, that is, FeK_α intensity increased in iron ore containing combined water when the combined water escaped from glass bead. On the other hand, FeK_α intensity decreased in one containing Fe(II) when the gain of oxygen occurred. (3) The correction factor when the bound water escaped from the glass bead and one when iron ore sample gained oxygen were theoretically derived from the standard curve for Fe-O system sample. (4) In experiments, it was shown that it was effective to correct weight change of iron ore sample (glass bead) in fusing for the determination of T.Fe content of iron ores.