| 摘要 |
PURPOSE:To obtain the subject precursor giving mullite powder having low cristobalite phase content and corundum phase content by adding a specific amount of an alkali to a slurry or an aqueous solution containing Al, and Si under specific condition. CONSTITUTION:The objective precursor is produced by adding an alkali (e.g. NaOH) to a slurry or an aqueous solution having pH of <=3 and containing Al, and Si at an Al/Si weight ratio of 65/35 to 80/20 in terms of Al2O3/SiO2 (e.g. an aqueous solution produced by mixing an aqueous solution of aluminum sulfate and an aqueous solution of sodium silicate at a specific ratio). The amount of the alkali to be added to the slurry, etc., is 2.10-2.70g-equivalent per 1 g-equivalent of Al in the slurry. |
