Process for preparing alkali metal cyanides

摘要

The invention relates to a process for preparing solid particulate alkali metal cyanides, in particular sodium cyanide, by reaction of hydrogen cyanide with aqueous alkali metal hydroxide solutions. In this process, a hydrogen cyanide-containing gas or liquid hydrogen cyanide is continuously brought into contact with finely divided droplets of aqueous metal hydroxide solutions, water formed during the reaction and also that introduced with the droplets is at least partially evaporated and the alkali metal cyanide formed is separated from the gas phase. The molar ratio HCN to alkali metal hydroxide is preferably from 1.5 to 5, the temperature in the reactor is preferably 105-300@C. The reactants are preferably fed into the reactor by means of two-fluid nozzles with external mixing. The process is more simply carried out industrially than known neutralisation processes; a saleable alkali metal cyanide is obtained in one step.