The solubility of Ca in Mn melt and the third-element interaction effects

Abstract

Solubility experiments of Ca in Mn melt were carried out in a Mo‐wire‐heated furnace. Small CaO crucibles, charged with the Mn alloys with small amount of Ca chips on top, were placed in an iron crucible, its lid being tightly sealed under red‐hot conditions. Relation of the solubility of Ca in pure Mn with temperature was formulated between 1 250 and 1 380°C. The effects of 3rd elements upon the solubility of Ca in Mn at 1 350°C were studied. Diagram showing the relation of Ig fjCa with [%j] (j = Si, Cr, Ni, Fe, Al, C and Ca) was drawn and ejCa evaluated. With the formula of Wagner, In γCa0 and εCaCa were found by regression analysis from the experimental data. The standard free energy of solution of Ca in Mn, based on the 1 wt.% standard at 1350°C was calculated, and its relation with T estimated.

Thermodynamic study of interaction coefficients in multicomponent metallic solutions by the solubility method

“…With the assumption that the solution of Ca in Mn is a regular solution: This value holds true in the neighbourhood of 1350 °C, and agrees very well with the value previously reported elsewhere 20 ).…”

“…The method of studying the solubility of an element in metal melt in presence of a third element has been widely used to determine the interaction coefficients. So values of interaction coefficients for C in the systems Fe-C-j 1 )-7 ), Mn-C-j 8 ), Ni-C-j 8 ) and Co-C-j 8 ), for Hin the system Fe-H-j9) 10 ), for Nin the system Fe-N-j 10 )-18 ), and for Ca in the systems Fe-Ca-j 19 ) as well as Mn-Ca-j 20 ) have been reported. However, appreciable discrepancy and inconsistency between values of interaction coefficients from different sources have aroused much embarrassment among metallurgists in respect to the selection of the most reliable data for application.…”

Thermodynamic Assessment of Liquid Mn–Fe–Si–C–Ca–P System by Unified Interaction Parameter Model

“…Si-C, 34,35,[45][46][47]56,[61][62][63][64] Mn-Fe-Si-C, 35,56,57,[63][64][65] Mn-i-Ca (i = Fe, Si or C) 46,66,67) and Mn-P. [68][69][70] However, reliable thermodynamic data are still very short to calculate the activities of different components in manganese ferroalloys at present. Since experimental measurements are both time-consuming and difficult at high temperatures, it is not possible to provide thermodynamic data for slag compositions in the many metallurgical processes; hence the need for a reliable model to estimate is urgent.…”

“…The Mn-i-Ca system was treated in the following way. 6.26 66) was taken as the value of ln γ Ca 0 at 1 623 K. And the saturated solubility of Ca in Mn melt X Ca sat is 2.055 × 10 − 3 at 1 623 K. 46,66,67) Thus, the value − 35.33 of ε CaCa was obtained according to Eqs. (28) and (29) And then, parameters of ε CaFe , ε CaSi and ε CaC are obtained according to Eqs.…”

“…(28) and (29) And then, parameters of ε CaFe , ε CaSi and ε CaC are obtained according to Eqs. (28) and (29) with the known ln γ Ca 0 and ε CaCa , and the experimental data from Ma et al, 46) Cheng 66) and Wei et al 67) Treated like ε CaCa , the effects of temperature on these parameters were The validity of these parameters was checked by calculating the Ca solubility in Mn-i-Ca melts. As shown in Figs.…”