Removal of Adsorbed Moisture on Iron Powders by Rice Husk Ash

Rice husk ash was proposed to be used for removal of adsorbed moisture on iron powders to enhance their flow characteristic. It was produced by burning of rice husk at 700 degrees C for 1 h, using a slowly increasing of heating rate (5 degrees C/min). The burning condition was determined from thermal gravitation analysis of rice husk. The obtained rice husk ash contained 99.7% amorphous silica with large specific surface area of 295 m(2)/g. Rice husk ash was effective in removal of adsorbed moisture on iron powders. Adsorption characteristic was found to be isothermal monolayer adsorption. The treated iron powders can be compacted more efficiently, obtaining green compact at a density higher than the untreated iron powders. Sintered billets of green compacts of treated iron powders showed a greater degree of particle bonding, having higher density and less fraction of pores.