Title: Development of a New Furnace for the Production of Rice Husk Ash
Author(s): N. Maeda, I. Wada, M. Kawakami, T. Ueda,
and G. K. D. Pushpalal
Publication: Symposium Paper
Appears on pages(s): 835-852
Keywords: chemical reactivity; compressive strength; ignition loss;
rice husk ash; silica fume; specific surface area; stirring furnace
This paper describes the process technology of the production of rice husk ash (RHA) as a supplementary cementing material. The incinerating tests of rice husks were carried out by changing the temperature and duration of incineration using a rotary kiln. From the incineration tests, it was concluded that the incinerating temperature should be lower than 550°C to obtain RHA with specific surface area larger than 50 m2/g, and the duration of incineration should be long enough to obtain RHA with ignition loss less than 3%. Based on the incineration test results with the rotary kiln, a new stirring type furnace is introduced in the present paper for the production of RHA with large specific surface area. An applicability of the stirring furnace is examined by changing the feeding rate of rice husks and rotation speed of stirrer. The RHA having specific surface area larger than 50 m2/g and ignition loss less than 3%, can be produced using the new stirring furnace at a temperature below than 5 0 0C. Using this high specific surface RHA, strength development properties of mortar were examined and compared to the mortar incorporating a lower specific surface RHA and silica fume. The compressive strength of mortar incorporating the high specific surface RHA was increased remarkably, and was higher than that of the lower specific surface RHA and silica fume. Furthermore, unlike other pozzolanic materials, mortar incorporating the higher specific surface RHA showed excellent early strength development.