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Removal of Cyanide from waste solutions

 

I am looking at neutralising exhausted cyanide solutions.

Anodic Cyanide cleaners.

Does any one have experience in the treatment of either using Bleach or hydrogen peroxide. Adding excess bleach is what I am using at present but am concerned about the reduction of any complexed cyanides. Also reaction times.

Also treatment of Sodium Carbonate crystal impregnated with Cadmium Cyanide.

Any help please.

Bernard Irving
- United Kingdom

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From BDH and other companies is a nice little cyanide test strip which is simple to use and found under water testing.

Use these and you can be sure you have treated the waste.

As to complex cyanides - leave the mixture for about half and hour after adding the bleach ⇦ bleach/sodium hypochlorite in bulk on eBay or Amazon [affil links] and test if you have a positive result add more bleach and wait, what happens is that the complexes break down release free cyanide which is destroyed then more complex breaks down. This goes on until you have no more bleach to break down the cyanide or all of the bleach is gone.

I find using the test strips it is better to know than to guess.

Martin Trigg-Hogarth
surface treatment shop - Stroud, Glos, England

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We have some very good success using ozone as treatment process. With the newer models of ozone units, it is becoming more efficient to use this promising technology for cyanide destruction. It requires some process treatability to determine the correct operating parameters and get good engineering data to design a system, but it can be very flexible and reliable. We were able to get cyanide concentrations to below 8 ppb with a nominal dosage.

The cadmium cyanide treatment is enhanced when you remove the cadmium first with a regenerable ion exchange resin system, that will allow the cadmium to be treated as if it was an acid cad bath, and not a cyanide. The cyanide will pass through the resin beds, and then can be treated as sodium cyanide, thus lowering the amount of dosage required in the ozone system.

Tom Baker
wastewater treatment specialist - Warminster, Pennsylvania

I need to find an adsorbent for CN waste that is generated on a ship. anyone have any suggestions? thanks

Brian Reed
- Baltimore, Maryland, USA
2006