Abstract: The present invention provides a process for the production of the triple salt 2KHSO.sub.5.KHSO.sub.4.K.sub.2 SO.sub.4 from sulphuric acid, hydrogen peroxide and potassium hydroxide, wherein, for continuous production, an aqueous working solution which contains KHSO.sub.5, sulphuric acid and potassium sulphate in a molar ratio of 1.3 to 2.5/1.2 to 2.0/1, is concentrated in an evaporation plant under reduced pressure and at a temperature of maximum 40.degree. C. to a concentration which corresponds to a content of 20 to 30% by weight of KHSO.sub.5, a partial stream is removed from the concentrated solution and from this, by cooling to a temperature below 15.degree. C., the triple salt is precipitated and separated, the mother liquor obtained is combined with the remaining solution, the solution is reconstituted by the addition of 90 to 100% sulphuric acid, 30 to 90% hydrogen peroxide and concentrated aqueous potassium hydroxide solution and recycled to the evaporation plant.