Process for producing alkali metal cyanide

Claim 1

THE PROCESS FOR PRODUCING ALKALI METAL CYANIDE WHICH COMPRISES BOILING WATER FROM A SLURRY OF ALKALI METAL CYANIDE CRYSTALS IN AN AQUEOUS SOLUTION SATURATED METAL CYANIDE CRYSTALS IN AN AQUEOUS SOLUTION SATURATE FROM THE CRYSTALLIZER TO MAINTIAN THE SOLUTION UNDER A SUFFICIENTLY LOW PRESSURE TO BOIL BELOW 80*C., ADDING CONCENTRATED AQUEOUS ALKALI METAL HYDROXIDE TO SAID SLURRY AT A RATE WHICH REPLACES WATER REMOVED AS STEAM, MIXING HYDROGEN CYANIDE VAPOR WITH SAID SLURRY TO FORM ALKALI METL CYANIDE BY REACTION WITH SAID LKALI METAL HYDROXIDE AT SUBATMOSPHERIC PRESSURE TO PREVENT THE TEMERPATURE FROM RISING ABOVE 80*C., TO THE RATE OF ADDITION BEING ADJUSTED TO MAINTAIN AN EXCESS OF 0.2% TO 3.0% OF ALKALI METAL HYDROXIDE THROUGHOUT SAID SATURATED SOLUTION, REMOVING A SLURRY OF ALKALI METAL CYANIDE CRYSTALS AND SOLUTION FROM THE CRYSTALLIZER, RECOVERING CRYSTALS FROM THE SLURRY AND RETURNING SOLUTION THE CRUSTALLIZER.