Abstract
Limonite, produced in Hokkaido, contains arsenic.
As arsenic cannot be removed during the refining process in both blast furnaces and open hearth furnaces, must be removed during the ore beneficiation process.
Limonite is normally sintered after mixing with foreign ores to remove arsenic.
During the process the gangue in mixed ores are considered to have some effects on the arsenic removal. In the present investigation the gangue was divided in three groups: acidic. (SiO2, TiO2), neutral (Al2O3) and basic compound (CaO, MgO), and the effect of these groups on the arsenic removal reaction was investigated.
The following results were obtained:
(1) Acidic compounds such as SiO2 and TiO2 had only a little hindering effect on arsenic removal. Especially the effect of SiO2 at a high temperature of 1300°C was very little.
(2) Neutral compounds such as Al2O3 also had only a little hindering effect on arsenic removal.
(3) Basic compounds such as CaO and MgO had a detrimental effect on arsenic removal and even the co-existence of small content of them decreased rapidly the arsenic removal ratio. The effect of MgO was rather little as compared with that of CaO especially at a high temperature of 1300°C.
(4) The behavior of arsenic in Dungun iron ore was very similar to that in Hokkaido limonite.
