Verfahren zur Entfärbung verfärbter Alkali- und Erdalkalicyanid-Lösungen

摘要

The invention relates to a process for the decolourisation of alkali metal and alkaline earth metal cyanide solutions for the purposes of separating polymeric hydrocyanic acid. The decolourisation is carried out by contacting the solution with an activated charcoal. Loaded activated charcoal is regenerated by washing and a thermal treatment at 250 DEG C to 500 DEG C in the presence of air or an oxidising gas.