Abstract:The isothermal phase diagram of SiO2-CaO-Al2O3 slag system was calculated by FactSage6.4. By fixing the agent MgO content at 8wt% and controlling Al2O3 content lower than 35wt%, a reasonable liquidus temperature and mineralogical phase of the glass slag were obtained. The effects of temperature, binary basicity wCaO/wSiO2 and Al2O3 content on viscosity of the feasible SiO2-CaO-Al2O3-MgO slag were investigated by the rotating spindle method and simulating calculation. Results show that with increasing the temperature, the slag viscosity decreases, Al2O3 content increases from 15wt% to 35wt% and binary basicity wCaO/wSiO2 increases from 0.3 to 1.0 according to the univariate investigation. It is known from the smelting experiment using iron as collector that the recovery rate of palladium increases with increasing the mass fraction of waste catalyst in material system, and it increases first and then decreases with continuously increasing the basicity and temperature. With the waste Pd/Al2O3 catalyst used in this study and using the optimized slag ingredients of about 30wt% Al2O3, 8wt% MgO and binary basicity wCaO/wSiO2=0.5, the recovery rate of palladium reaches 99% and the residual palladium in glass tailing is less than 4.50 g/t.