Abstract: Based on sodium recovery boiler technology，the effects of different technological parameters on the sodium sulfide conversion and SO2 releasing were experimentally studied.The results showed that：1 200 ℃ reaction temperature，550~830 μm coal particle diameter，and 8~10 min resident time in the sodium sulfide recovery boiler were the better parameters，and under those conditions the sodium-sulfide conversion rate could achieve 93.67%.But continually increasing the reaction temperature and resident time had few effects on the sodium sulfide conversion rate.The mass ratio of mirabilite to coal should be controlled at 1∶（1.05~1.15） to achieve the suitable sodium sulfide conversion rate and low coal consumption.In the atmosphere with oxygen，SO2 was mainly produced by the oxidation of sodium sulfide.The SO2 from the oxidation of sodium sulfide was much higher than that from the pyrolysis and oxidation of coal.Therefore the SO2 releasing can be reduced by controlling the oxygen content in the reaction zone.As the reaction temperature increase，the SO2 releasing time largely reduced.The exorbitant reaction temperature would promote the oxidation of sodium sulfide and hence increase the SO2 releasing.

Key words: Sodium sulfide recovery boiler, technological parameter, Na2S conversion rate, SO2 releasing