Patent ID: 8894961
Filing Date: 2014-11-25
Classification: C01C,C01P

Abstract:
1. A process for the production of sodium cyanide crystals comprising; (a) contacting impure hydrogen cyanide and sodium hydroxide in a reactor with mixing for a maximum contact time of 5 seconds; (b) feeding the resulting mixture to a continuous evaporative crystallizer to produce a slurry of sodium cyanide crystals; (c) passing the slurry of sodium cyanide crystals from the crystallizer via a transfer line and alternating the flow of the slurry between at least two heat exchangers or at least two discrete areas of a hot surface to purposefully precipitate and remove sodium carbonate onto one heat exchanger or one area of the hot surface, while deposited sodium carbonate is cleaned from the other heat exchangers or other areas of the hot surface, and continuously recycling said heated slurry back to the crystallizer after removal of the sodium carbonate; and (c) separating the sodium cyanide crystals from the slurry.