EFFICIENT METHOD FOR DECONTAMINATING WASTE GASES AND WASTE WATER CONTAINING CYANIDE IN A METHOD FOR PRODUCING ALKALI METAL CYANIDES

The invention relates to a method for producing alkali metal cyanides as solids, comprising the steps: i) an absorption step in the form of the absorption of hydrogen cyanide from a syngas containing hydrogen cyanide in an aqueous alkali metal hydroxide solution; ii) a preparation step for the waste gases containing cyanide that have accumulated in step i); iii) a crystallization step in the form of the introduction of the alkali metal cyanide solution into an evaporative crystallizer; iv) a condensation step for the vapour containing cyanide that has accumulated in step iii) to obtain a vapour condensate containing cyanide; v) a recirculation step, in which the vapour condensate containing cyanide that has been obtained in step iv) is used as an aqueous liquid in step ii).