PROCESS FOR PRODUCTION OF AMMONIUM THIOSULPHATE

摘要

A process for continuous production of ammonium thiosul- phate, (NH4)2S2O3 (ATS) from NH3, H2S and SO2 comprising steps of: (a) partial condensation in a partial condenser 4 of a first gaseous or partial liquid feed stream comprising H2O, H2S and NH3 with a molar H2S:NH3 ratio < 0.4; (b) passing the aqueous condensate comprising NH4HS and NH3 from the partial condenser 4 to a reactor 9 in which said condensate is contacted with a third feed gas stream 7 comprising H2S and with an aqueous solution 10 comprising NH4HSO3 and (NH4)2SO3 under formation of an aqueous solution of (NH4)2S2O3; (c) passing the gas stream comprising NH3 and H2S from the partial condenser 4 to a mixing device 13 in which said gas stream is completely dissolved in the water drained off from the aerosol filter 25; (d) passing a second feed gas stream 20 comprising ap- proximately 2/3 mole SO2 per mole of NH3 contained in the first feed stream to a SO2 absorber 21 and the aerosol fil- ter 25; (e) passing the aqueous solution produced in mixing de- vice 13 to the SO2 absorber 21; (f) passing the off gas from the absorber 21 to the aerosol filter 25 and (g) adding to the aerosol filter 25 a balance amount of water required for obtaining approximately 40-65 wt% (NH4)2S2O3 in the aqueous of solution of (NH4)2S2O3 being withdrawn from the reactor 9.