WHITTLE RECYN CASE_2017

2 T HE R E CYN™ P ROCESS

The “ReCYN” process is the name given to a specialist technology, which is being offered for the recovery of cyanide and dissolved metals from precious metal plant process streams. The process is based on the use of a functionalised resin bead, pre-treated to allow the dual duty of recovering free and complexed cyanide ions from solution with a high degree of efficiency. The GGT Treatment Plant is custom-designed for each operation to match the various solution chemistries and throughputs. The two areas of cyanide recovery and metal detoxification are balanced to achieve the desired compliance levels. Equally applicable to slurries and solutions, the process is technically and economically superior to all others currently available for the detoxification of gold plant tailings. The ReCYN™ technology can provide a significant opportunity to reduce operating costs and at the same time improve environmental performance. The resin-based process offers a proven method for achieving virtually complete removal and efficient recovery of cyanide, dissolved base metals and precious metals from gold plant process streams. For most tailings treatment applications, significant overall net revenue will be achieved. The cost of cyanide recovered is usually less than 50% of the cost of new cyanide and there are no expensive detox processes. In addition to its applications in cyanide recovery and tailings detoxification, Green Gold Technologies Pte Ltd has also demonstrated major opportunities as an alternative to carbon in the main recovery section of precious metal plants. The ReCYN™ Process is owned by Green Gold Technologies Pte Ltd, a Singapore based company. Green Gold Technologies Pte Ltd has an exclusive engineering agreement with PT Green Gold Engineering (GGE), an Indonesian based company, for the key engineering aspects of the ReCYN™ Process. GGE has full in-house capability for both design and construction. Eluted resin is added to the CIL tails and flows co-current through a series of adsorption tanks. A counter-current system is employed if very low residual values are required such as for direct river discharge from the Tailings Storage Facility (TSF). o Loaded resin is separated from the ReCYN™ plant tails and transferred continuously to the elution section of the plant. o The loaded resin is split between the cyanide andmetal elution columns with the ratio of flows dependent on the solution values. o Metal elution and cyanide elution occur in separate continuous columns at ambient temperature. o Metal recovery typically involves either electrowinning or precipitation to remove copper and other metals. o Cyanide recovery involves volatilization and scrubbing to form a concentrated cyanide solution that can be returned directly to the leach and elution circuits. o The detoxified slurry is discharged to the tailings dam. o A separate ReCYN™ solution treatment circuit can be added to treat Tailings Storage Facility overflow for river discharge. 2.1 F LOWSHEET o

This process flow is visualised in Figure 7 overleaf:

ReCYN™ Case Study – Martabe Operations

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