Zinc chloride-ammonium chloride double salt prodn. - from waste gas, esp. flux prodn. from hot dip galvanising off-gas

摘要

Zinc chloride-ammonium chloride double salts are produced from waste gases contg. onr or more of zinc chloride, ammonia and hydrochloric acid by scrubbing the gases with a minimum amt. of water which is recirculated for further enrichment, analysing the aq. soln. obtained, adding one or more of zinc oxide, hydrochloric acid, zinc chloride or ammonia to obtain the stoichiometric compsn. of the double salt and opt. crystallising out the salt by distilling off part of the water from the soln. Method is used for treating waste gases from chemical plants or esp. hot dip galvanising plants to obtain flux solns. or dry flux for hot dip galvanising.