Preparation of sintered brick from thermal desorption residue of oily sludge and analysis of environmental performance

Oily sludge is a hazardous solid waste generated during the exploitation of oil and gas. After recovering oil, the residue can be utilized for sintered bricks. A Central Composite Design (CCD) was used to optimize the formulation of sintered bricks. The result showed that the compressive strength (CS) of the sintered brick reached the maximum (12.43 MPa) at the sintering temperature 976.8 degrees C, the holding time 100 min, and OSTDR incorporation 23.8 %. X-ray fluorescence spectroscopy, X-ray diffraction, synchronous thermal analysis and scanning electron microscopy analysis showed that the mosaic structure of mullite and glass phase increased the CS of sintered brick. The nonuniform pores created by excess organic matter in OSTDR will have a negative effect on the CS of sintered bricks. In addition, the TCLP leaching test was carried out for the heavy metal pollutants of sintered bricks, and the environmental risks of sintered bricks were evaluated by the Nemerow index method. The environmental risk of sintered bricks is "clean". Therefore, preparing sintered bricks is a promising and feasible resource utilization direction of OSTDR.