The invention relates to a method for the hydrolytic precipitation of iron as jarosite from a sulphate-containing solution in connection with zinc recovery from zinc calcine. The recovey contains neutral leach, ferrite leach, zinc electrolysis and iron precipitation stages. The ferrite included in the calcine is leached with return acid of the electrolysis after which the iron present in ferrous form is neutralized and routed to an iron precipitation stage, where the iron is oxidised to the trivalent form using an oxygen-containing gas. Also present in the precipitation stage arc Na, K or NH.sub.4 ions and jarosite nuclei.