Ash and sulphur removal from bitumen using column flotation technique: Experimental and response surface methodology modeling

This study investigates removing ash and pyrite sulphur from bitumen by column flotation process. Central composite design (CCD) of response surface methodology (RSM) was applied for modeling and optimization of the percentage of ash and pyrite sulphur removal from bitumen. The effects of five parameters namely the amounts of collector and frother agents, particle size, wash water rate and feed rate on percentage of ash and pyrite sulphur removal from bitumen were investigated. The used bitumen sample has 26.4% ash and sulphur content of 9.6% (6.81% in the pyrite sulphur form). All the tests were carried out under aeration rate of 4L/min and pulp containing 5% of solid using pine oil and kerosene as frother and collector agents, respectively. The coefficient of determination, R2, showed that the RSM model can specify the variations with the accuracy of 0.971 and 0.975 for ash and pyrite sulphur removal from bitumen, respectively, thus ensuring a satisfactory adjustment of the model with the experimental data. The RSM was used to optimize the process conditions, which showed that initial amount of collector of 2.00 kg/t_bitumen, amount of frother of 0.2 ppm, particle size of 101.29 mesh, wash water rate of 0.5 L/min and feed rate 1.26 L/min were the best conditions. Under the optimized conditions, the maximum percentage of ash and pyrite sulphur removal from bitumen was 88.74% and 90.89%, respectively.