Effect of Li2CO3 on the preparation and performance of lightweight building ceramsite from oil-based drilling cutting pyrolysis residues

Abstract

In order to achieve promising performance and ensure a high utilization rate of oil-based drilling cuttings pyrolysis residues (ODCPRs) for fabricating the lightweight building ceramsite, Li₂CO₃ was employed as a novel sintering additive during the sintering process in this work. The influence of Li₂CO₃ addition on the bulk density, apparent density, expansion rate, 1 h water absorption, compressive strength and pore structure of the ODCPRs-based lightweight building ceramsite under different sintering temperatures were comprehensively studied. Furthermore, the high-temperature phase evolution mechanism and pore structure analysis of the ODCPRs-based lightweight building ceramsite were deeply discussed by the means of the thermal analysis high-temperature phase analysis and Micro-CT. The research findings suggested that the incorporation of Li₂CO₃ as a sintering additive can reduce the density and foaming temperature of ceramsite, while enhance substrate strength and facilitate the formation of low-temperature liquid phase of ceramsite. Attributed to the disparity in ionic radii between Li⁺ and Al³⁺, defect reactions will occur within the celsian crystal structure, thus reducing the activation energy for solid-phase reactions and effectively promoting their occurrence. Consequently, this effect would facilitate the formation of celsian crystals in ceramsite, and the obtained ODCPRs-based lightweight building ceramsite demonstrated desirable performance characterized by a relatively lower density, enhanced mechanical properties, and increased porosity. Thus, above findings has provided valuable insights for the utilization of recycled oil-based drilling cuttings.