Study on the Equilibrium Between Liquid Iron and Calcium Vapor

Abstract

The solubility of calcium in liquid iron at 1823 K and 1873 K (1550°C and 1600°C) as a function of calcium potential was studied experimentally. The measurements were performed using a closed molybdenum holder in which liquid calcium and liquid iron were held at different temperatures. The results indicate a linear relationship between the activity of calcium, relative to pure liquid calcium, and the mole fraction of dissolved calcium in liquid iron, with a negligible temperature dependency in the ranges studied. The activity coefficient of calcium in liquid iron at infinite dilution, c CaðlÞ ; was calculated as 1551.

Effect of Aluminum on the Solubility of Calcium in Liquid Iron at Low Calcium and Aluminum Contents

“…The experimental setup used has been described in detail in a previous publication by the authors 4) and only a description of the experimental procedure is given below.…”

“…The calcium contents obtained in the samples are in the lower range of what has previously been studied. [1][2][3][4] It should, however, be noted that the expected contents of dissolved calcium in iron during ironmaking and steelmaking are significantly lower. The aluminum contents cover what is normally seen in aluminum killed steels, which is the focus of the present study.…”

Partitioning of Calcium Between Liquid Silver and Liquid Iron

“…This article is an open access publication One of the common methods for performing thermodynamic studies on metallurgical systems is to equilibrate a suitable reference system, for which the thermodynamic properties are well known, with the system of interest. Due to the very low solubility of calcium in liquid iron, [1][2][3][4] iron-calcium alloys are not suitable as reference system for thermodynamic measurements on calcium containing phases at steelmaking temperatures. An alternative is the silver-calcium system.…”

“…A detailed description of the furnace setup can be found in a previously published work [1] and only a brief description is given here. A vertical resistance furnace with Kanthal Super heating elements and an alumina reaction tube was used.…”

“…Thus, by using the analyzed calcium content in the iron and data on the activity coefficient of calcium in liquid iron published previously, [1] the calcium activity could be calculated. For the following calculations of the activity of calcium, relative to pure liquid calcium, it was assumed that the activity coefficient of calcium in iron is constant in the composition range studied and has the value 1551.…”