Preliminary Studies on the Recovery of Bitumen from Nigerian Tar Sands: I. Beneficiation and Solvent Extraction

Abstract

Abstract Solvent extraction of bitumen from Nigerian tar sands using toluene has been investigated. Pulverization of the tar sands followed by agglomeration in a mechanical shaker resulted in spherical agglomerates having higher bitumen contents than the mined tar sand. The extent of beneficiation was 4% and 19% for the high grade and low grade sands, respectively Temperature, agitation, and tar sand/solvent (S/L) ratios were found to be significant variables affecting the dissolution of bitumen from the sand. S/L ratio has the greatest effect on extraction efficiency. The rate of bitumen extraction, expressed as extractability η∗ showed great dependence on agitation. About 16- and 15-fold increases in extractability were obtained for SIL ratios of 1/20 and 1/5 respectively for a 2.8 fold increase in agitation At the initial stages of extraction, asphaltene content of the bitumen extracted at 50°C was less than that in the bitumen extracted at 25°C. This finding could have significant implications for the...