Effect of chemical additives on oil shale natural floatability

Abstract

Abstract Improving the organic content in oil shale before retorting is a substantial target. The flotation process is proven as a good separation process for hydrophobic particles from their associated impurities. In this study, the natural floatability and the flotation with different types of reagents were investigated to show how effective these reagents are in improving their organic content (kerogen). Frothers such as pine oil and kerosene and collectors such as oleic oil and amine acetate were tested. The results indicated that the addition of any used reagent negatively affects the oil shale floatability. The descending order of flotation using chemical reagents, in terms of combustible grade and recovery, is natural floatability, with frothers, then with collectors. The grade and recovery of the naturally floated fraction are 18% and 92.7%, respectively, from 8.75% in the feed sample. The low dosage from either oleic acid or pine oil effectively reduced the grade and recovery to about 15% and 86%, respectively. Chemical reagents stand as barriers to particle–bubble attachment. The presence of higher dosages of frother leads to the agglomeration of the smaller organic particles, which leads to lower grades and recovery. While collectors play a significant role in increasing the flotation of inorganic particles rather than the organics.