Solidification method for phosphate bonded alumina cement by hydrothermal hot-pressing

The hydrothermal hot-pressing method is a very usefull technique for solidifying various inorganic materials. The authors have tried to apply some cementitious materials to this process. A commercially available alumina cement is used and the effects of addition of sodium phosphate and silica fume are examined to increase the strength of solidified alumina cement. The reaction temperature is 250 degrees C, and the reaction time is 60 min. The maximum tensile strength of the solidified bodies reached at about 23 MPa when alumina cement is replaced by 2.5 mass% of silica fume and modified with 10 mass% of sodium metaphosphate.