Evaluation study for lubricant grease prepared from Iraqi bentonite

摘要

The present research is directed toward preparation of bentonite grease from Iraqi bentonite by converting the hydrophilic bentonite into organophilic in order to ensure depression into the base stock oil. Quaternary ammonium chloride and bromide with 8 carbon atoms as a minimum requirement were used. Results indicate that the chloride salt was more efficient than bromide salts, and the optimum percent of salt added was 30% which resulted in calcium ion exchange. Two types of base oil stocks were used: stock 60 and stock 150 with a viscosity of 67.25 and 414.73 cSt, respectively. Methanol (1 wt.%) was used as a dispersion agent at 40°C to yield homogeneous mixture and air bubbles free. Wax (7 wt.%) was added to prevent the isolation between base oil and thickener, 5% (by vol.) asphalt was used with the base oil stock 150 which gave a grease with a viscosity of (575 cSt) and drop point of 250°C. Different bentonite percentages were used to prepare grease, the results showed that increasing the bentonite percentage and viscosity caused in: (1) decreasing the penetration point; (2) increasing the drop point and resistance to grease washout.