Solubility of Calcium in CaCl2-CaO

Abstract

The solubility of calcium in calcium chloride - calcium oxide is of interest in processes reducing metal oxides in calcium chloride based salt systems. The solubility of calcium in calcium chloride was measured as 2.7mol% at 1073K. This reduced to 0.4mol% at a calcium oxide content of 9.0mol%. Experimental data for the binary components of the calcium - calcium chloride - calcium oxide ternary system has been used to construct a model of the ternary system, against which the results reported here are compared. At high calcium oxide concentrations there is reasonable agreement between model and experiment; at low calcium oxide concentrations the model predicts lower calcium concentrations than found experimentally.

Ni/NiO Reference Electrode Potential Measurements in Molten CaCl2–CaO

“…Based on published data from Shaw and Watson, the solubility of Ca in the melt is predicted to be less than 0.16 wt% in CaCl 2 -CaO (5 wt%). 29 Thus, Ca must have been partitioned between the salt phase and a pure liquid phase. The DOR process will have excess Ca metal, so the material needs to be able to withstand contact with the liquid metal.…”

Electroanalytical Measurements of Oxide Ions in Molten CaCl2on W electrode

“…CaO is soluble to 18.5 wt% in CaCl 2 at 1123 K. 3,4,7 CaWO 4 has a solubility of 15 mol% in molten CaCl 2 at 1123 K. 46,47 The only insoluble species in Eq. 9 is W, and there is an abundant amount of W metal near the W WE surface.…”

“…1,2 The solubility and thermodynamic stability of oxide ions in these melts makes CaCl 2 an attractive flux for the reduction of oxides to metal. [3][4][5][6][7] It also has been the subject of extensive research and development as an ideal medium for the electrolytic reduction of titanium oxide, [8][9][10][11][12][13][14] scheelite (calcium tungstate), [15][16][17][18] rare earth oxides, [19][20][21][22] other metal oxides [23][24][25][26][27] and conversion of CO 2 28,29 due to its solubility for oxide ions. In some cases, the solubilization of oxide ions into CaCl 2 is desirable.…”

Thermodynamic Properties of CaCl<sub>2</sub>-CaF<sub>2</sub>-CaO System: Phase Diagram Investigation

“…Similar results were obtained by Perry et al [11] specifying that the 20 -22 mol.% CaO region may exhibit a peritectic point instead of eutectic point. However, Wenz et al [1] did not report it: they proposed a peritectic point at 18.5 mol.% melting at 835˚C and suggested the CaO(CaCl 2 ) 2 compound at 33 mol.% CaO which was considered in Shaw et al study [12],…”