Refining of fossil resin flotation concentrate from Western coal. Third quarterly final report, July 1, 1993--September 30, 1993

Abstract

Summary of Batch Extraction Experiments: (1) Resin extraction rate is not significantly affected by agitation intensity and low agitation should be suitable for the continuous extraction process; (2) The effect of resin particle size on the extraction rate and yield is obvious. Because of the fine size of the composite resin concentrate (80% minus 200 mesh), the extraction reaction occurs in reasonable times and process design conditions can be established accordingly; (3) The effect of temperature on the rate and yield of the extraction process is found to be very significant. Higher temperatures (about 60{degree}C) should be considered for the continuous extraction circuit; (4) The effect of solids concentration on the extraction rate is moderate. As concluded from our characterization study, it is known that fossil resin is mainly composed of aliphatic components, partially aromatized multicyclic compounds with a small number of oxygen functional groups. The solvent, heptane, is also a nonpolar aliphatic compound. It is expected that no chemical reaction will occur in such an extraction process at low temperature (0--90{degree}C). The main interaction between resin and heptane is expected to be the van-der-Waals-forces of interaction associated with solvation phenomena. In this regard, the resin extraction rate should bemore » largely independent of agitation intensity at room temperature, low solids concentration and moderate agitation. The initial extraction rate was found to be inversely proportional to the initial particle diameter. The temperature has significant effect on extraction rate and the activation energy for resin extraction by heptane was found to be 15.5 kcal/mole. The resin extraction kinetics can be expressed by the equation given.« less