Preparation of CaO-MgO-ZrO2 refractory and its desulfurization effect on Ni-based alloy in vacuum induction melting (VIM)

The effect of micromonoclinic ZrO2 addition on properties of CaO-based refractories was investigated in our work. Zero, 5 wt%, 10 wt%, and 15 wt% micromonoclinic ZrO2 powders were added into CaO-MgO (CaO-based) refractories. The obtained results indicated that with the introduction of micromonoclinic ZrO2, the density increased slightly after heated at 1600 °C for 3 h. The results indicated that the density and mechanical properties of the samples were improved after introducing micromonoclinic ZrO2. The hydration resistance of the samples was improved with appropriate proportion of ZrO2. However, excessive ZrO2 damaged the hydration resistance of the samples. The influence of monoclinic ZrO2 on the samples was mainly caused by CaZrO3, the reaction product of CaO and ZrO2. The details of the CaZrO3 effects on the samples were discussed in this paper. Besides, based on the experiment results, CaO-based crucible was prepared and used in desulfurization. The desulfurization effects were compared with desulfurizer: Al. Desulfurizer reduced the content of [O] and [S] in the alloy obviously.