Interaction between lithium and oxygen in the liquid copper

O.V. Samoilova, G. G. Mikhailov, L. A. Makrovets, E. A. Trofimov

ABSTRACT:

The thermodynamic modeling of phase equilibria at the copper-rich corner of the Cu–Li–O system is performed in the conditions of existence of the metal melt. The Cu2O–Li2O phase diagram is plotted during of the thermodynamic modeling. The melting temperature and heat of fusion of the LiCuO compound are estimated. The activities of the (Cu2O, Li2O) oxide melt components are calculated for the temperatures 1300 and 1500°С using the theory of subregular ionic solutions. For these temperatures in the investigated interval of concentrations, the activities of the copper oxide and the lithium oxide in the oxide melt are characterized by negative deviations from Raoult’s law. The thermodynamic analysis of interaction processes in the Cu–Li–O system in the conditions of existence of the metal melt based on copper is carried out using the calculation method of the surface of component solubility in the metal melt for the temperature range by 1100 to 1300°С. The isotherms of oxygen solubility in the copper melt containing lithium are plotted. Lithium is shown as an effective deoxidant and it’s able to reduce the oxygen concentration in the copper melt up to 10–6 wt % at the temperature 1200°С. Experimental studies of the Cu–Li–O system samples were performed too. The types and compositions of non-metallic inclusions were defined using a scanning electron microscope and the X-ray microanalysis. The research results can be used for the technology analysis in the copper and the copper-based alloys production.

KEYWORDS:

 phase equilibria, copper melt, Cu–Li–O system, thermodynamic modeling