硫酸滓の塩化揮発焼結法における2, 3の問題

抄録

Some questionable problems on the chloride volatilization process of pyrite cinder were mainly discussed in terms of thermodynomic properties of the redctions and several series of experiment were also carried out in order to clarify these problems. Calcium chloride was selected as the chloridizing reagent, because the pellets obtained by this process are commonly used in the iron making blast furnace. The results obtained can be summarized as follows.
(1) To remove the metal impurities from pyrite cinder as much as possible, the sample should be rapidly heated, especially in the temperature range from 600 to 1000°C.(2) Decreasing in elimination efficiency by slow heating might mainly be due to the decomposition of calcium chloride at low temperature by the sulfur coexisted in the pyrite cinder.(3) The pyrite cinder containing comparatively low sulfur and arsenic is more suitable for this process as the raw material.(4) The existence of moisture and sulfur dioxide in the furnace gas is extremely harmful for the elimination of impurities.(5) The best results concerning the elimination of impurities were obtained at the heating temperature of 1100°C.(6) In order to obtain the pellets having enough mechanical strength and to eliminate the sulfur coexisted, the pellets are desirable to heat at about 1200°C.