The purpose of this paper is to examine the effect of reaction parameters on the preparation of SiAlON powder. The conditions to obtain maximum concentration of nitrogen in the product were also examined and discussed. SiAlON (silicon aluminum oxynitride) powders have been prepared from Huntley fly ash in a tubular laboratory high-temperature furnace through carbothermal reduction and nitridation reactions. Almost pure beta-SiAlON can be produced from fly ash at 1300 degrees C in a nitrogen atmosphere. Depending on the reaction conditions, the nitrogen content could reach as high as 30%. Nitrogen in the SiAlON products was measured by a nitrogen/oxygen analyzer. X-ray diffraction and Brunauer-Emett- Teller surface area analysis have been used to further characterize the products.