We have synthesized BaFe12O19 samples by ammonium nitrate melt technique (ANMT) at temperatures from 850 to 1200 degrees C. Calcinations at 850-1000 degrees C yield single domain grains having reasonably high coercive fields up to 4500 Oe. Higher temperature calcinations decrease the coercive fields due to multi-domain grain growth. Washing the samples in HCl is effective to reduce the impurities, especially the antiferromagnetic BaFe2O4. HCl-washing increases magnetization by about 50%; the saturation magnetization increases from 36-45 to 58-62 emu/g and the residual magnetization from 21-26 to 32-34 emu/g. (c) 2005 Elsevier B.V. All rights reserved.