CO ガスおよび CO-CO_2 混合ガスによるマンガン鉱石の還元 : マンガン鉱石の性状および還元に関する研究 II

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Authors studied on manganese ore reduction with CO gas or CO-CO_2 gas mixture by the method of thermal balance analysis, and then discussed its reducibility with mineral composition. (1) Reducibility decreases in the next order : i. e. MnO_2 ore, burnt ore of MnCO_3 (manganese low oxide ores such as α-Mn_2O_3 or Mn_3O_4 etc.) and manganese silicate ore. It is plain enough that every ore is reduced to MnO with CO gas. (2) There is scarcely any difference in reducibility with CO gas among all MnO_2 phases i.e. cryptomelane, pyrolusite, γ-MnO_2 and birnessite. Only, MnO_2 transforms to reduced state (till Mn_3O_4) through mere thermal decomposition simultaneously with reduction by CO gas. Therefore, authors support the general reasoning that easily thermal-decomposable and incomplete crystalline γ-MnO is most reactive. (3) Under low temperature reduction, the obtained MnO is unstable in the air after cooling in CO gas flow. Meanwhile it is shown that through reduction at above 700℃, the obtained MnO is rather stable in the air after cooling. X-ray diffraction shows that this phenomenon is due to crystalline structure. (4) During manganese ore reduction with CO gas, carbon deposition is observed in certain ores ; especially in high iron-content ores this tendency is remarkable. (5) On the basis of above results, some discussions are made on refining furnace reaction and preliminary reduction.
社団法人日本鉄鋼協会の論文
1963-08-01