Sodium cyanide process
AssigneeE. I. Du Pont de Nemours and Company
InventorsJames David Allison, Brent Ellsworth Basham, Steven Lamar Grise
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Abstract
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 about 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 over a hot surface to precipitate onto the surface and remove sodium carbonate, and passing said slurry back to the crystallizer; and (d) separating the sodium cyanide crystals from the slurry.
Claims16
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.
Dependencies are inferred from the claim text.