Takaho Otomo

Effect of Heating Temperature for Fusion on Purification of the Raw Iron Oxide from the Zinc Leach Residue, and the Synthesis of Mn-Zn Ferrite used Resultant Purified Iron Oxide.

The purification of raw iron oxide obtained from iron precipitation of the Zinc leach residue using the recrystallization method with Na2B4O7 flux and magnetic properties of Mn0.95Zn0.05Fe2O4 synthesized from resultant iron oxide has been investigated.The main purposes of present study are to decrease the heating temperature as much as possible for reduction of the purifing energy cost, and to examine effects of decrease in heating temperature on iron oxide morphology and removal of Zn, S, As, and effect of iron oxide purity on magnetic properties of Mn0.95Zn0.05Fe2O4 synthesized from resultant iron oxide.The main results obtained as follow:(1) Morphology of purified iron oxide is returned gradually from hexagon crystals pseudoparticles of original raw material as heating temperature is decreased.(2) From removal of Zn, S and As, heating temperature is possible to decrease from 1573K to 1273K.(3) Purity and magnetic properties of iron oxide have nearly no influence on magnetic properties of synthesised Mn0.95Zn0.05Fe2O4 ferrite.

EFFECTS OF THE PRIOR WATER WASHING AND REDUCTION OF AMOUNTS OF NA2B4O7 FLUX ADDITION ON PURIFICATION OF THE RAW IRON OXIDE FROM THE ZINC LEACH RESIDUE AND THEIR MAGNETIC PROPERTIES

The purification of raw iron oxide obtained from iron precipitation of the zinc leach residue using the recrystallization method with Na2B4O7 flux and their magnetic properties has been investigated. The main purpose of present study are to examine the effect of the prior water washing and decrease of amounts of Na2B4O7 flux on the purification of raw material. As a result, it was recognized that the prior water washing of raw material are undesirable, because of decrease of desulfurization in the purification by the sub-sequent recrystallization method,and the elimination of Zn, S and As in raw material is the best, when raw material/flux ratio is 70/30 and the prior water washing is not carried out. The magnetic properties is similar to that of α-Fe2O3 single crystal. The synthesis and magnetic properties of Mn-Zn ferrite from purified iron oxide were also examined.

Activity Measurements of SnO in The Molten SnO-SiO2 System.

In the pyrometallurgical treatment of tin, it has been known that the selectionof optimum slag composition has a significant to promote a smelting efficiency.In order to decide the slag composition, it is essential to investigatethe thermodynamic characteristics of the molten slag, such as the activity of SnO in the slag.In the present study, the activity of SnO in the molten SnO-SiO2 binary systemwhich is the basic system of tin smelting slag was studied by EMF methodusing a zirconia solid electrolyte, and then the influence of addition of CaO, FeO and Al2O3 components on the activity of SnO was also examinated.The results obtained are summarized as follows:1) The activity of SnO in the molten SnO-SiO2 system shifts from positive tonegative compared with Raoults low as the molar ratio of SiO2 is raised.2) The activity of SnO raises by additing CaO to SnO-SiO2 system, and this effecttend to be remarkable with increase of SiO2 content in the slag.3) The influence of FeO addition on the activity of SnO in SnO-SiO2 system isnot observed remarkably, but the activity of SnO raises slightly only in thecase in which SiO2 content in slag is high.4) The influence of Al2O3 addition on the activity of SnO in the SnO-SiO2 systemis not so observed.