State-of-the-Art on the Feasibility Assessment of Recycling of Oil Refinery Wastes in Cement Composites with Particular Emphasis on Spent FCC Catalysts

Currently, the significance of oil refinery industry is unquestionable because of the increasing demand for petrochemical products, such as fuels, monomers, and organic chemicals. Despite this, apart from high greenhouse gas emissions, numerous oil and natural gas refining processes are distinctly associated with the generation of a considerable amount of Oil Refinery Wastes (ORWs) in different forms, which need proper disposal and valorization. Nonetheless, at present, solid ORWs are mainly sent to landfills. Such a procedure, apart from high disposal costs, results in significant environmental pollution related to the release of chemical contaminants to soil and water environment. Consequently, these pollutants might poison natural flora and digestive systems of animals, thereby contributing to the general degradation of useful land and a serious health risk. To cope with that issue, ORW recycling in cement-based materials might be considered a reliable course of action, as the hardened concrete is capable to bind contaminants that ORW comprises. This article focuses on actual literature knowledge, limitations, and chances in the scope of a comprehensive approach to sustainable management of ORWs through their utilization in cementitious composites. The special emphasis was placed on presenting the impact provided by the addition of ORWs on the numerous performances of cementitious mixes and hardened concrete. The environmental and economic aspects were also discussed, particularly in the scope of CO2 emission reductions and cost savings. Finally, the proposal for future tests, including investigating the correlation between valorization of ORWs and toxicity of ORW-blended composites, were proposed.