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SGS is a world leader in cyanide technologies.


We have developed many technologies that help manage and recycle cyanide used in your gold recovery operation. Copper can also be recovered.

Rising costs and rising environmental concerns have led to an increased interest in cyanide recovery and recycling in gold processing operations. SART (sulfidization, acidification, recycling and thickening) is an industry standard process that helps you to efficiently manage and recycle the cyanide in your operation while complying with environmental regulations concerning cyanide destruction.

SART is an adaptation of the time-tested acidification, volatilization, reneutralization (AVR) treatment for gold tailings. It was developed to treat gold plant tailings solutions that contain high concentrations of copper cyanide. Cyanide recovery has a significant impact on the economics of processing high cyanide-consuming copper-gold orebodies since less cyanide is required overall in the plant.

When cyanide is destroyed in a gold recovery operation, the costs and hazards associated with the purchase, delivery and destruction of the reagent represents a substantial portion of total operating costs. This cost can be converted into a new stream of revenue when cyanide and copper are recycled from the tailings and the recovered Cu25 is sold as a by-product. At the same time, savings in the purchase and delivery of new cyanide increase your bottom line. As well, the requirement for less cyanide means less is transported to your site. Overall, SART helps you ensure compliance with environmental regulations concerning cyanide.

There are four steps in the SART process:

  1. Sulfidization – Sulfur ions are added to the gold tailings
  2. Acidification – The pH of the solution is lowered to around 4.5. Under these conditions, the copper cyanide complex breaks down completely, releasing the cyanide as HCN gas and converting the copper to the mineral chalcocite (Cu2S)
  3. Thickening – The chalcocite is thickened and filtered. The mineral is now a saleable by-product
  4. Recycling – The recycled cyanide is returned to the gold recovery segment of the operation

The SART process has been used successfully at several full-scale mining operations and more plants currently under construction. 

SGS is a leader in the SART process. We provide flowsheet development, testing, pilot plant development and ongoing support at full-sized operations using SART and other cyanide recovery processes. Contact us early in your proposal and planning stage to see if SART can improve the bottom line, ensure regulatory compliance in your gold recovery operation and improve your environmental footprint.

This service is not currently available in this country. However, we have an unrivalled global network. Please contact us to discuss the delivery of this service.