11.15.05
Patent No. US 6,710,091 B1: Bayer AG, Leverkusen, Germany, patented a process to prepare nano-sized zinc oxide particles. The method includes carrying out basic hydrolysis of at least one zinc compound in alcohol and/or water mixture; leaving the precipitate to mature until the zinc oxide has completely flocculated; thickening the precipitate to produce a gel and separating the gel from the supernatant phase.