Liquid purification or separation – Processes – Ion exchange or selective sorption
Reexamination Certificate
2005-07-19
2005-07-19
Hopkins, Robert A. (Department: 1724)
Liquid purification or separation
Processes
Ion exchange or selective sorption
C210S670000, C210S684000, C210S688000, C423S024000
Reexamination Certificate
active
06919030
ABSTRACT:
A process for recovering cyanide from feed material containing cyanide and copper involves the steps of: (a) contacting the feed material with a strong base anion exchange resin whereby copper and cyanide from the feed material are adsorbed onto the resin; (b) contacting the resulting resin with an eluant solution containing free cyanide ion to elute copper and cyanide from the resin; (c) separating the eluted resin from the eluting solution or eluate from step (b); (d) acidifying the eluate from step (b) to precipitate copper; (e) separating the acidified solution from the precipitate in step (d) and alkalizing directly or after concentration the separated solution containing HCN; (f) contacting the eluted resin from step (b) with an acid to condition the resin and remove additional cyanide while leaving most of the copper in the resin phase; (g) converting the HCN solution formed in step (f) to cyanide ion, directly or after concentration of the HCN solution, by the addition of alkali; and (h) returning the conditioned resin from step (f) to step (a) above.
REFERENCES:
patent: 4708804 (1987-11-01), Coltrinari
patent: 5605563 (1997-02-01), Kidby et al.
patent: 5807421 (1998-09-01), Fleming et al.
Davis, M.R. et al., Proposed Solvent Extraction Route for the Treatment of Copper Cyanide Solutions Produced in Leaching of Gold Ores, National Symposium on Cost Effective Gold Recovery from Refractory Ores, Melbourne, Australia, Jul. 1998.
Goldblatt, E., Recovery of Cyanide from Waste Cyanide Solutions by Ion Exchange, Industrial and Engineering Chemistry, (1959), pp. 241-246, vol. 51:3.
Fleming Christopher A.
Thorpe John A.
Hannah Technologies Limited Partnership
Hopkins Robert A.
Senniger Powers
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