24 Mar RECYN Application
Each unique project has a specific solution depending on the ore type and environmental compliance conditions. The economics will vary with plant size, free cyanide levels, and solution chemistry.
There is no simple answer, but there is an answer.
The experience of the last 30 years has shown that any project can be accommodated using the RECYN Process for cyanide recovery and tailings detox.
There are three parts to the evaluation process: free cyanide recovery, detoxification, and metal recovery:
- Cyanide recovery is simply an economical consideration, although often it will overlap with detox requirements. The two commercial applications in Indonesia are based on free cyanide recovery; but they find this also satisfies detox requirements, resulting in substantial cost savings and recovery benefits. The capital cost is easily justified and usually results in payback in less than one year. Economics are more favorable for larger projects and higher cyanide levels.
- Detox is a more complex evaluation because it involves detailed solution chemistry and compliance requirements. The same adsorption plant can be used for detox, but a metal recovery plant must be added. The evaluation generally splits into two areas, compliance for tailings dams and compliance for river discharge. Either level can be accommodated with the RECYN process. The cyanide code level of <50ppm CN WAD for discharge to tailings dams is easily achieved, usually just by free cyanide recovery. For river discharge, the levels are more country specific, but can easily be accommodated with the RECYN process, usually by including a metal recovery stage.
- Metal recovery is required for the detox of tailings, but can be assessed on a stand-alone economic basis if there is no detox requirement.
A preliminary evaluation requires a few basic details to be inputted to an evaluation model that gives capital and operating costs and cost-benefit information. The assumption is that no capital benefit is derived from existing plant equipment.
The GreenGold website has a template for a preliminary assessment.