A study was undertaken to production Of Si3N4 Powders by carbo-thermal reduction and nitridation (CTRN) of diatomite. Test samples were prepared by mixing 99% purity and mean powder size of 2.4 mum of carbon black and maximum particle size of 150 mum diatomite with C/SiO2 molar ratio 4. Prepared sample was subjected to CTRN process at temperatures of 1300, 1350, 1400, and 1450 degreesC for 4. 8, and 16 h. CTRN process was conducted in an atmosphere controlled tube furnace in nitrogen flow 5 cm(3)/min. All products were examined by XRD and SEM-EDX to determine the transformation, morphology and chemical composition. The results showed that the best Si3N4 transformation occurred at 1400 degreesC for 16 h. (C) 2003 Elsevier Science Ltd. All rights reserved.