1983 Volume 99 Issue 1150 Pages 1067-1073
Reducibilities of the iron oxide contained in the leach residue with CO gas, and with coke in molten state were investigated. The latter is composed of two kinds of experiments; one uses an external-heating type small electric furnace, the other uses a resistance type smelting electric furnace. Finally, a possibility to make dechromiumed iron was examined. These are summarized as follows:
(1) Reducibility of the iron resources with CO gas.
a) The reduction rate in early stage of the iron oxide with CO gas is remarkably large. It is explained by the reason of that the material has an extremely large specific surface area.
b) Since the reducibility reached to 60-70%, the reduction rate of the iron oxide noticeably slows down for some reason or other.
(2) Reducibility of the iron resources in molten state by using an external-heating type furnace.
a) The iron oxide is reduced in molten state at 1400°C and is separated from slag layer with the optimum amount of flux.
b) The recovered metal contains 2% order of chromium and its chemical composition nearly corresponds to that of Japanese Industrial Standard of “Grinding balls and cylpebs (2nd category)”.
(3) Reducibility of the iron resources in molten state by using a resistance type smelting furnace.
a) This was performed as an applied experiment and the expected results were obtained.
b) Tension test, hardness test, abrasion test and microscopic observation of three kinds (Cr: 4.1%, 1.6%, 0.8%) of test pieces prepared from the molten metal were performed. Their results were almost adequate.
(4) Possibility for making dechromiumed iron. By melting without solid reducing agent of the reduction product from CO gas reduction, the iron containing 0.06% of chromium was recovered. This chromium content is quite applicable value to make common steel.
