In production of clean steel or special grades of steel, calcium is injected during ladle furnace process in order to remove inclusions. However, normal Alumina-ZrO2-carbon slide gate plates suffer from calcium vapor attack leading to chemical corrosion and shortening the life of the plates. In this research, a new MgO-spinel-carbon slide gate plate was developed to overcome the drawback of Al2O3-ZrO2-C ones. The result was also compared to a commercially available MgO-C slide gate. In this regard, the chemical analysis, physical and mechanical properties as well as mineralogical composition of all the plates were investigated. The different corrosion mechanisms of each plate were discussed. The result showed that although the commercial imported MgO-C carbon plate had the best performance in practice, the domestically developed MgO-Spinel-carbon plates also showed much better performance than Alumina-Zirconia Carbon and can be used safely for flow control of Ca-Treated steel.