Abstract: The total amount of radioactive organic waste oil that is temporarily stored is small. And it's not easy to be solidified directly. In this paper, sulphur-aluminate cement and emulsion solidification method are used to solidify the simulated radioactive waste engine oil. Taking different oil capacity in the solidification matrix as the variable, the mechanical properties, leaching resistance and freeze-thaw properties of the solidification matrix are analyzed in accordance with the national standard GB 14569.1—2011. The results show that when the oil capacity is less than 25% (mass ratio), the properties of the solidification matrix meet the relevant requirements of national standard GB 14569.1—2011. On this basis, the thermal stability, porosity and phase composition of different oil solidification matrix were investigated by gradient temperature rise method, TG, XRD, SEM and static nitrogen adsorption instrument. The experimental results show that when the oil capacity is less than 16.67%, the thermal stability of the solidification matrix is excellent. When the oil capacity is 12.5%, the micro pores and pore diameter of the solidification matrix are the smallest, so the strength of the solidification matrix under this oil capacity is the highest. When the oil capacity is less than 25%, the addition of engine oil will not inhibit the hydration process of sulphur-aluminate cement and the differential curve of pore size distribution of cement solidification matrix.

Key words: radioactive waste oil, sulphur-aluminate cement, cement solidification, micro-structure