This study concerns production of a new composition for plaster of tundish in continuous casting of steel to have less difficulties in blocking and hot corrosion. Blocking is caused by the presence of low melting oxides in plaster producing melts at high temperatures and diffusion and reaction of permanent and working layers. Due to penetration of SiO 2 rich slag into porou plaster, monticellite(CaMgSiO 4 ), merwinite(Ca 3 Mg 2 SiO 8 ), tephroite(Mn 2 SiO 4 ) and rodonite (MnSiO 3 ) with respectively the melting point of 1490?C, 1575?C, 1345?C and 1290?C are developed around MgO particles and causing corrosion. In this study 3 groups of binders, silicates, phosphates and sulphates were employed. Cold crushing strength, Apparent Porosity% and Bulk Density were measured, together with XRD and SEM studies. Different amounts of olivine were used in the plaster. Results showed that magnesium sulphate is the best binder, giving proper green strength and no melting point phase. XRD and EDX analysis of corroded samples showed that olivine reduces SiO 2 penetration into plaster. Forsterite in olivine acts as nucleation agent to lead penetrated SiO 2 to forsterite formation, which is a refractory and corrosion resistant phase. The side effect is that the melting point of olivine is less than MgO. The best amount of olivine mass found to be 10-15% in plaster to reduce SiO 2 penetration into porous plaster and not lowering refractories under load. Keywords Hot corrosion, Plaster of tundish, Binder, Blocking.
