Evaluation of the Effect of Nanofibrillated Cellulose on the Drying and Dewatering Behaviour of Oil Sands Tailings

ABSTRACT: As a sustainable material, Nanofibrillated Cellulose (NFC) is increasingly used in reinforcing earth-based materials due to its unique mechanical and physical properties. It has been used in enhancing the geotechnical properties of oil sands tailings for the first time. Preliminary study has found that NFC can improve the shear strength of oil sand fluid fine tailings (FFT). However, the use of NFC would potentially change the dewatering behavior of FFT in the meantime. This current study aims to evaluate the influence of NFC addition on the geotechnical properties of FFT, including drying behavior, shear strength gain, soil-water characteristics, and dewaterability. A favorable treatment method for the optimal dose was determined using 2 different sources of FFT based on the near-surface shear strength gain subject to atmospheric drying in the lab. Capillary suction time (CST) and pressure filtration tests were carried out to evaluate the influence of NFC on the immediate dewatering and filterability of FFT. In addition, laboratory experiments using Tempe cell, Pressure plate extractor, and WP4 Dewpoint Potentiometer were conducted to assess the water retention behavior of the FFT samples, which demonstrate the influence of NFC on the desaturation of FFT. Consequently, it was noted that adding NFC would potentially affect the evaporation rate, CST, specific resistance to filtration (SRF), and the desaturation point of FFT. However, the impact on these properties varies between FFT with different sand to fine rate (SFR) or fines content.