A system (10), process and apparatus are disclosed for purifying carbon black (15) containing sulfur and metal oxide impurities by digesting (20) the impure carbon black in an acid to extract the metal oxide (25). Sulfur (45) is then removed from the acid treated carbon black (30) by solvent extraction (35) with an organic aromatic solvent which is then recovered (50). The purified carbon black (40) is then suitable for use as a toner (60) by toner black processing (55).
CROSS-REFERENCES TO RELATED APPLICATIONS
This patent application claims the benefit of U.S. Provisional Application No. 60/256,005, filed Dec. 15, 2000, of the same or similar title.
