Sodium cyanide process
View Patent ↗A process that can be used to produce NaCN is provided. The process comprises contacting hydrogen cyanide with sodium hydroxide solution to produce a NaCN solution and crystallizing the NaCN solution wherein the process is carried out in the presence of an acid or a metal salt of the acid in which the acid has a pKa≦4.4. The NaCN crystals can be separated from the slurry and dried.
1. A process comprising contacting HCN with aqueous NaOH to produce a solution comprising NaCN and crystallizing said NaCN to produce slurry of NaCN crystals wherein said process is carried out in the presence of glycolic acid or a metal salt of said acid.
2. A process according to claim 1 wherein the molar ratio of said acid to said hydrogen cyanide is in the range of from about 0.001:1 to about 1000:1.
3. A process according to claim 2 wherein said NaCN crystal is separated from said slurry and is dried to produce a dried NaCN crystal.
4. A process according to claim 1 wherein said process is carried out in the presence of said glycolic acid.
5. A process according to claim 4 wherein said process is carried out in the presence of sodium glycolate.
6. A process according to claim 5 wherein the molar ratio of said sodium glycolate to said hydrogen cyanide is in the range of from about 0.001:1 to about 1000:1.
7. A process according to claim 6 wherein said NaCN crystal is separated from said slurry and is dried to produce a dried NaCN crystal.
8. A process according to claim 3 further comprising dissolving said NaCN crystal with water to produce a solution and contacting an ore with said solution.
9. A process according to claim 7 further comprising dissolving said NaCN crystal with water to produce a solution and contacting an ore with said solution.
10. A process comprising (1) contacting a HCN with aqueous NaOH to produce a solution comprising NaCN and (2) crystallizing said NaCN, in the presence of glycolic acid or a metal salt of said acid, to produce NaCN crystals wherein said metal is an alkali or alkaline earth metal.
11. A process according to claim 10 wherein said process is carried out in the presence of glycolic acid.
12. A process comprising (1) contacting HCN with aqueous NaOH to produce solution of NaCN; (2) crystallizing said NaCN, in the presence of glycolic acid or sodium glycolate, to produce NaCN crystals; (3) separating said crystals from said solution; and (4) drying said crystals.
13. A process according to claim 12 wherein said process is carried out in the presence of glycolic acid.
14. A process according to claim 12 wherein said process is carried out in the presence of sodium glycolate.