Preparation of Inorganic Consolidated Body Using Aluminium Hydroxide Mechanically Activated by Dry Milling

Aluminium hydroxide (Al(OH)₃) was mechanically activated by dry milling. In order to develop an inorganic consolidated material, the structure and reactivity of milled Al(OH)₃ were investigated and consolidated bodies were prepared using the reaction between activated Al(OH)₃ and a potassium silicate solution. Milling up to 1 h apparently reduced the grain size and promoted amorphization, although milling longer than 2 h did not give a significant physical change. Milled Al(OH)₃ directly transformed to -Al₂O₃ around 270°C. The transformation temperature decreased with increasing milling time. The remarkable enhancement of the reactivity was attained. The reactivity of Al(OH)₃ milled for 2 h improved 1000 times more than that of as-received Al(OH)₃. The preforming paste, prepared with as-received Al(OH)₃, could not consolidate at room temperature without drying. On the other hand, for Al(OH)₃ milled for 2 h, the preforming paste consolidated in 10 min and the consolidated material showed much better resistance against water than that prepared with as-received Al(OH)₃. The possibility of a new inorganic consolidated material was suggested using the reaction between mechanically activated Al(OH)₃ and the potassium silicate solution.