Ash and Sulphur Removal from Bitumen

Flotation and leaching methods were used to remove ash and sulphur from bitumen by sulfuric acid. The bitumen samples had sulphur content of 9.6% (6.74% in the pyrite sulphur form) and 30% ash. All the experiments were done under aeration rate of 4L/min using pine oil and gasoline as frother and collector agents, respectively. The factors studied were including the amounts of collector and frother agents, pH, and the solid weight percentage in the pulp, stirrer speed, and particle size. The bitumen samples with dimensions less than 0.5 mm were crushed. The flotation experiments were performed in a 3-liter Denver laboratory flotation cell to ease the ash and sulphur removal. The optimum condistion obtaind from the results were; foaming amount of 50gr/t, collector amount of 1kg/t, impeller speed of 1200rpm, pH=7, pulp containing 5% of solid, particle size of 100mesh, and flotation time of 3 mins. In these circumstances, 52.9% of pyrite sulphur (e.g.; 36.45% of total sulphur) and 43% of ash were removed. With the approach of leaching with sulfuric acid, the organic and pyrite sulphur removal were 7% and 13%, repectively. Combination of these two methods (in optimal conditions), removed up 47% of the total sulphur and 61% of ash through bitumen sample.