Quantification of Magneesia Dissolution in Silicate Melts and Diffusivity Determination Using Rotating Finger Test  
[PERSON] Quantification of Magneesia Dissolution in Silicate Melts and Diffusivity Determination Using Rotating Finger Test. 2022122122  
this study, CWTD was used to take advantage of its high-resolution in-situ measurement. Although dissolution has been studied using HT-CLSM, the impacting phenomena and parameters, such as the Stefan flow and the effect of bath movement, were not considered in the evaluation [18; 24; 25; 26; 27; 31; 32; 33; 34; 35; 36; 37; 38; 39; 40; 41; 42; 43; 44; 45; 46; 47; 48; 49; 50; 51; 52; 53; 54; 55; 56; 57]. Accounting for the Stefan flow and the effect of bath movement necessitates the application of the diffusion-convection equation. The Stefan flow was considered in Ref. [58], but the effect of bath movement was not considered; however, both parameters were considered in Ref. [28].  
The literature about magnesia dissolution reveals the following: The dissolution of magnesia in different slags using HT-CLSM and the corresponding diffusivity determination were reported previously [18; 27; 34; 57]. In those studies, magnesia particles of irregular shape were used, and the diffusivity determination models were based on spherical particles; this could lead to incorrect results, especially at the beginning of the dissolution. Some researchers have used RFT to quantify continuous wear using cylindrical magnesia samples [8; 21; 38; 48]. The results obtained from RFT are expected to be more accurate than CLSM studies because the effective diffusive boundary layer thickness could be defined in RFT by the experimental parameters [28]. However, the determination of the diffusivity of magnesia from RFT has not yet been studied. [PERSON] et al. [38] and [PERSON] et al. [8] calculated the mass transfer coefficients from RFT experiments with MgO-C refractories; however, the mass flux used in their calculation includes the erosive mass flux in addition to the corrosive flux due to the limited erosion resistance of a cylindrical ordinary ceramic MgO-C material. Ordinary ceramic materials with a maximum grain size of several millimeters are widely studied. However, to the best of our knowledge, dense magnesia fine ceramics, which are necessary for diffusivity determination from solely corrosive mass flux, have not yet been investigated. This may be the primary reason for the lack of magnesia diffusivity data from RFT studies. Therefore, to obtain reliable results solely from the corrosive mass flux, RFT studies with fine magnesia ceramics are necessary.  
In this study, we investigate the dynamic corrosion of fine magnesia ceramics and determine the effective binary diffusivities of magnesia in silicate slags. Cylinders of magnesia fine ceramics were used for the RFT experiments in silicate slag with a CaO/SiO\({}_{2}\) weight ratio of 0.65 at 1450, 1500, and 1550 \({}^{\circ}\)C with 200 rotations per minute (rpm). The diffusivity calculation technique based on the Sherwood relation was adopted from Ref. [15]. The Arrhenius plot was used to test for plausibility of the diffusivities [15]. All the diffusivity values quoted in this study are effective binary diffusivities.