Effect of chromium powder on physical and chemical properties of magnesia-chrome refractory

The magnesia-chrome specimens were prepared using magnesite clinker, chromite and chromium powder as raw materials, carboxymethylcellulose sodium as binder, after pressing, firing at 1 600 ℃ for 3 h to determine the effect of chromium powder on the physical and chemical properties of magnesia-chrome refractory. The effect of chromium powder (mass percent were 0 %, 0.3%, 0.5 %, 1%, 1.5% respectively) on physical and chemical properties of magnesia-chrome refractory were researched, including, porosity rate, flexural strength, compressive strength and thermal shock resistance. The results show that the porosity of samples is obviously reduced and its strength is improved with the addition of 0.3 % chromium powder. However, the properties would be worsened if the addition of chromium powder were too excessive. The strength of the specimen added 1.5 % chromium powder is obviously decreased with increased porosity. Moreover, the size of pores become larger, owing to the serious expansion of the oxidation reaction of chromium powder. To improve the properties of magnesia-chrome refractory, the addition of chromium powder should be around 0.3 %.