Hydrometallurgy: Leaching in Heap, Vat, CIL, CIP, Merrill–Crowe, SX Solvent Extraction

Hydrometallurgy: Leaching in Heap, Vat, CIL, CIP, Merrill–Crowe, SX Solvent Extraction 2017-04-04T06:57:36+00:00
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Cyanide Detoxification Methods (5 replies)

Tony Verdeschi
2 years ago
Tony Verdeschi 2 years ago

I wanted to know more about cyanide detoxification methods. Am currently using hydrogen peroxide to do my test and also read about SMBS Sodium Metabisulfite.  Are there other methods?

Bill Fraser
2 years ago
Bill Fraser 2 years ago

One place I have worked used SMBS and Copper sulfate to detox Cyanide to wad levels below 10ppm. CuSO4 as an activator/catalyst followed by SMBS.

Bob Mathias
2 years ago
Bob Mathias 2 years ago

Hydrogen Peroxide in combination with Copper sulphate as the catalyst, is typically only used for treating solutions, as peroxide consumption is high when treating slurries . The INCO Sulphur Dioxide/Air process is commonly used for treating slurries. Another alternative is Caro's Acid (H2SO5) which is produced onsite by reacting H2SO4 and H2O2, and is used on a few sites. I have also seen activated carbon used, in combination with an Aachen reactor and oxygen.

Helena Russell
2 years ago
Helena Russell 2 years ago

As pointed out Hydrogen Peroxide is only used for solutions, the presence of solids causes H2O2 to break down before it can detoxify the cyanide. Even fine precipitates produced by the detoxification process will drive up peroxide consumption. The INCO process (SO2/O2) is suitable for either solutions or slurries and can get to the lowest CNwad levels, generally with the lowest operating costs.

Batch tests are only useful for determining the minimum cyanide content that can be achieved in the effluent. Continuous tests are required to determine conditions such as residence time, reagent dosage ratios, pH, and oxygen transfer. These factors are all dependant on ore type and must be determined through lab tests.

The Gekko Global Cyanide Detox Group can provide testing services, as well as design and supply of cyanide detoxification processes and on-site performance auditing. Contact me if you would like further details

Alan Carter
2 years ago
Alan Carter 2 years ago

Sodium Metabisulfite that release SO2 and copper sulfate as a catalyst. However, if you have CN complexes including Co or Fe, you may need something else to destroy the complexes. H2O2 is expensive and decompose very easily. 

Good luck.

1 year ago
David 1 year ago


about  cyanide detoxification methods, see this PDF.

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