Enhancement of bitumen recovery from the oil sand in an alkaline solution using ultrasound irradiation and carbon dioxide

Herein, we demonstrated the enhancement of bitumen recovery from the oil sand in a concentrated alkaline solution using ultrasound irradiation and carbon dioxide. The alkaline solution allowed the separation of bitumen and sand; however, it was difficult to collect bitumen via aeration. CO2 exhibited a high contact angle for bitumen even at a high pH. Therefore, we attempted to use CO2 for bitumen recovery under ultrasound irradiation, increasing the number of collisions between bitumen and the CO2 bubbles; thus, the bitumen recovery ratio exhibited a high value of approximately 70% even at a low CO2 injection rate of 20 ml min−1.