Abstract: Simultaneously producing base oil and de-oiled wax are the main measures to increase the economic benefits for the traditional base oil production. However, the quality of the de-oiled wax from vacuum cut 4 produced by reverse scheme is poor for its high impurity content and makes the difficulties in wax refining process to achieve the wax quality index. The study for the wax showed that by refining with selected clay followed by hydrofinishing as well as adding antioxidants and UV inhibitors could improve the color and light stability of refined wax. A process scheme for refining inferior heavy de-oiled wax was proposed.

Key words: reverse process, vacuum cut 4, de-oiled wax, clay treating, hydrofinishing, light stability