In the work, single-phase β-SiAlON was prepared from a powder mixture based on aluminum ferrosilicon and aluminosilicate (kaolin) with nitrogen-containing additives (product of nitriding of the starting mixture and NH4F) by combustion synthesis followed by acid enrichment of the synthesized product. Self-propagating combustion synthesis was conducted under natural nitrogen filtration. The synthesis parameters (nitrogen pressure, sample diameter, density of the starting mixture) and the conditions of acid enrichment of the synthesized products (acid concentration, temperature of acid enrichment and dispersion of the starting powder) were determined. After acid enrichment of the synthesized product, which contained β-SiAlON and α-Fe phases, the phase content of β-SiAlON was 99.5 wt%.