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Melting Relations of CaO‐Manganese Oxide and MgO‐Manganese Oxide Mixtures in Air
Author(s) -
RIBOUD P. V.,
MUAN ARNULF
Publication year - 1963
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.1963.tb13767.x
Subject(s) - manganese , periclase , spinel , liquidus , ternary operation , oxide , manganese oxide , solidus , solid solution , phase diagram , eutectic system , chemistry , phase (matter) , inorganic chemistry , materials science , crystallography , metallurgy , alloy , microstructure , organic chemistry , computer science , programming language
Melting relations in the systems CaO‐manganese oxide and MgO‐manganese oxide in air have been determined at temperatures up to 1705°C. In the system CaO‐manganese oxide four crystalline phases have stable existence in equilibrium with liquids: lime (approximate composition CaO‐MnO), spinel (approximate composition Mn 3 O 4 ‐CaMn 2 O 4 ), and two ternary solid solution phases in which Ca/Mn ratios as well as oxygen contents vary over considerable ranges. One of these ternary solid solution phases may for the sake of simplicity be represented approximately by the formula CaMnO 3 and the other by the formula CaMn 2 O 4 . Three isobaric invariant situations exist, with temperatures and phase assemblages as follows: At 1588°± 10°C the two crystalline phases lime and CaMnO 3 coexist in equilibrium with liquid (40 wt% CaO, 60 wt% manganese oxide) in a peritectic situation. Another peritectic at 1455°± 5°C is characterized by the equilibrium coexistence of CaMnO 3 , CaMn 2 O 4 , and liquid (25 wt% CaO, 75 wt% manganese oxide). A eutectic situation exists at 1439°± 5°C with CaMn 2 O 4 , spinel, and liquid (18 wt% CaO, 82 wt% manganese oxide) present together in equilibrium. In the system MgO‐manganese oxide in air periclase‐manganosite solid solution (approximate composition MgO‐MnO) and spinel (approximate composition Mn 3 O 4 ‐MgMn 2 O 4 ) are the only crystalline phases present in equilibrium with liquids. Liquidus and solidus temperatures increase with increasing MgO content. A peritectic situation exists at 1587°± 10°C, with the two crystalline phases coexisting in equilibrium with liquid (1 wt% MgO, 99 wt% manganese oxide).