Abstract:The pyrite catalyst used in direct coal liquefaction was prepared by mechanochemical reaction. The dispersing and interface action of pyrite in non-polar organic medium of heptane with or without disperants were studied. The behaviors of agglomeration and dispersion in non-polar organic medium were illuminated with DLVO theory. The results show that stearic acid and 1-octadecanol were effective to improve the dispersity of pyrite. For hydrophobic pyrite, there was no polar interaction energy in pyrite-heptane with polar dispersants. The interaction was dominated by Lifshitz-van der Waals interaction energy.