This study was carried out to develop a process for synthesising ultra-fine boehmite powders by precipitation from the Bayer process liquor at a temperature within the range 85 ~ 95 ^oC. The study was conducted to investigate whether boehmite produced by this technique has the same physical properties as those prepared by hydrothermal synthesis at elevated temperature and commercially available for use as fire retardant in plastic making. As with gibbsite, the precipitation of boemite requires seeding in which α-boehmite seeds were first produced by pyrolysis of a plant ultra-fine gibbsite at 420 ^oC for 60 min. The boehmite seeds of mean particle size (D₅₀) of 0.30 μm were obtained through subsequent hydrothermal synthesis.
 This process would yield a high purity well-crystalline boehmite of 1.30-1.47 μm mean particle size of low surface area (2 ~ 4 m²/g) as required for commercial fire retardants.

Keywords: Boehmite, Bayer process, Hydrolysis, Pyrolysis, Precipitation