ALTA_2020 - ReCYN III The New Generation of Gold Plants

concentration cyanide solution is required. The cyanide eluted resin is discharged to a resin transfer tank to be pumped back to the adsorption circuit. The resin flow rate through the elution column, and subsequently through adsorption, is determined by the cyanide level in the CIL/CIP discharge, and automatically controlled by a variable speed rotary valve at the outlet of the column. Variations to the basic ReCYN I flowsheet include simultaneous recovery of cyanide and zinc from Merrill- Crowe plant tailings. Zinc is eluted by sulphuric acid at the same time as cyanide but recovered in a separate precipitation step. The combination of co-current adsorption, continuous elution and immediate return of cyanide to the leach circuit makes for a simple and efficient cyanide recovery circuit. RECYN II The presence of sufficient WAD cyanide complexes in the tailings slurry that require a detoxification step to meet discharge compliance is accommodated with ReCYN II. For small quantities of WAD cyanides, less than 100ppm as CN, a combined cyanide and metal adsorption section is used. However, for larger quantities, two-stage adsorption is preferred as shown in Fig. 2 ReCYN II FlOWSHEET.


Slurry Flow Resin Flow Solution Flow

Carbon Safety Screen U/F Metal Eluted Resin

Resin Sizing Screen



Precipitate Thickener

Loaded Resin Screen

H 2 SO 4


Copper Elution Column

Metal Adsorption Tank

Filter Feed Tank

Copper Reactor Tank

Loaded Resin Tank


Copper Filter

Copper Concentrate

Cyanide Eluted Resin

Scrubbing Column

Resin Sizing Screen

Loaded Resin Screen



Cyanide Adsorption Tank

Cyanide Elution Column

Safety Screen

Recycle Cyanide Solution to Leach Tank

Recycle Cyanide Tank

Loaded Resin Tank

H 2 SO 4

Tailing Dam

Tailings Hopper

Fig. 2 ReCYN II Flowsheet

The metal cyanide complexes are removed before the free cyanide using a similar adsorption circuit for both duties, generally three stages of twenty minutes each, in a co-current flow. Copper elution is more efficient with a higher CN:Cu ratio on the loaded resin thus favouring the staged adsorption steps. The slurry tailings from the metal adsorption stage flows to the cyanide recovery adsorption circuit where the free cyanide is then recovered as per ReCYN I.

ALTA 2020 Gold-PM Proceedings


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