Dambrowitz, Christopher (Northern Alberta Institute of Technology)

Purpose

Fluid fine oil sands tailings (FFT) remain suspended in oil sands tailings disposal ponds for decades as a result of the low settlement or consolidation rate. This study explores a method of treating FFT with lime or with lime and carbon dioxide to improve FFT dewatering, strength and release water quality and to demonstrate benefits for non-segregating tailings technologies. Graymont Western Canada Inc., a North American leader in the supply of lime and limestone products, wishes to investigate the process performance using one of its lime products. NAIT's Centre for Oil Sands Sustainability (COSS), in collaboration with Graymont, will determine the impact of varying a) lime dosages and b) adjusting pH using CO2 on short- and long-term volume reduction as well as strength development in treated FFT. The residual bitumen removal from the treated FFT will also be recorded. This project builds a foundation for long-term collaboration as Graymont seek to position their technology into the Alberta oil sands marketplace. The technology has a strong potential to enhance economic and environmental sustainability in the oil sands industry. The objective of this project is to evaluate the suitability of adding lime, and lime plus CO2 in non-segregating and polymer-flocculated thickened tailings treatment processes. The suitability will be evaluated by investigating the impacts of iterative lime, and CO2, and polymer treatments on settling rate and final solids content, material strength, static yield stress, flow properties, rheology, and bitumen removal.