Beneficiation of Himmetoglu oil shale by flotation as a solid fuel substitute. Part 1. Materials characteristics and flotation behavior

In this study, the processing of Himmetoglu oil shale from Bolu, Turkey, by flotation techniques was investigated for the possibility of achieving a clean solid-fuel substitute. The surface characteristics and mineral content of Himmetoglu oil shale were determined using mineralogical, XRD, and FIR analysis. The flotation response of the sample was tested with several nonionizing collectors and a variety of ionizing collectors belonging to both cationic and anionic groups. The effects of collector dosage and pulp pH on the effectiveness of flotation were also determined. XRD analysis showed that majority of incombustible matter in the sample was carbonate, silicate, and sulfide minerals. FTIR spectrum exhibited significantly strong absorption bands from the organic and oxygen-rich functional groups, revealing the organic-rich and highly humic character of Himmetoglu oil shale. Flotation experiments showed that Himmetoglu oil shale had a hydropbillic nature and extremely poor flotability because of its humic character. Effective means of ash rejection with an acceptable extent of combustible recovery was achieved by reverse flotation, where mineral matter was selectively removed by amine acetates through reverse flotation. Among the amine acetates used, the most favorable cleaning was obtained in the presence of Flotigam CA at natural pulp pH, where the ash yield of Himmetoglu oil shale was reduced from 34.76 to 23.52% with a high combustible recovery of 83.57%.