Summary for cyanide electrolysis Discussion
Cyanide electrolysis waste water treatment is discussed as a long-used but somewhat specialized method for destroying concentrated cyanide waste. Ajit Menon asked where to find more information on cyanide destruction by electrolysis. Parameswaran Iyer said that, in his experience, electrolytic treatment can reduce free cyanide to about 100–200 ppm, and that adding chloride ion to the waste, around 1–2 g/L, is necessary; he noted that mild steel can serve as the cathode, while the anode must be a material that can withstand the service, such as a noble-metal oxide Dimensionally Stable Anode (DSA), though graphite also works but is consumed. Tom Ted Mooney added that the technology has existed for 30–40 years since Dr. Leslie Lancy’s mid-1960s patent, but it has seen limited attention because of maintenance and electrode costs, even though electrons are chemically inexpensive and newer materials have improved practicality.
Q. Recently somebody suggested “Cyanide Electrolysis” for destruction of concentrated cyanide waste water. Would somebody help me as to where I can find some more information about Cyanide destruction using Electrolysis ?
Ajit Menon
– Rapid City, South Dakota
2000
A. In my experience, electrolytic treatment will bring “free” cyanide down to 100 – 200 ppm. It’s necessary to add some chloride ion to the waste – 1 – 2 g/l should be ample. The cathodes can be mild steel, or whatever. The anodes need to be made of some material that will stand up to this service. Those noble metal oxide electrodes often called Dimensionally Stable Anodes (DSA) are made by several companies and ought to work. Graphite I know works, but it gets eaten up in the process.
Dave Wichern
Consultant – The Bronx, New York
2000
A. The Electrolytic destruction of cyanide waste can be accomplished by adding common salt to the waste liquid at 25 g per litre and electrolizing between stainless steel cathodes and graphite anodes at about 6 volts DC.
The waste liquid must be maintained below 25 °C by use of a chiller or else the chlorine will escape before it reacts with the cyanide.A waste containing 5 g/ lit cyanide can be successfully treated in about 4 hours.The completion of the treatment can be monitored with
starch paper
[affil link] and iodide turning blue.Best of luck!
Parameswaran Iyer
– Hyderabad, AndhraPradesh, INDIA
2000
A. Ajit,
This technology has been around for a long time (30-40 yrs) since Dr. Leslie Lancy patented an electrochemical destruction system back in the mid 60’s. It hasn’t gotten as much attention, mostly because of the issues associated with maintenance costs or the electrodes. Chemically, nothing is cheaper than an electron, though, and material science (and competitive pricing) have caught up to the technology base now.
Tom
Tom Baker
wastewater treatment specialist – Warminster, Pennsylvania
2000
Q. Dear Sir,
I would like to know the best available method for destruction of low concentration of cyanide ( below 10 mg/litre) present in weak ammoniacal liquor(coke plant flushing liquor). The residual cyanide concentration should be below 0.2 mg/litre sincerely
balaram bhattacharya
– burnpur, west bengal, India
2000
Q. Greetings,
Recently I was asked to write a report about Electrolysis and how can we use it in wastewater treatment.
I have basic knowledge regarding the “Electrolysis” process. And that the negative charged ions go to the anode and the positive charged ions go to the cathode. But I can not understand the process of treating waste water with this technology.
Sultan,
Regards
Sultan Alhamdan
– Manchester, Lancashire, UK
March 16, 2013
A. Hi Sultan. It’s difficult to take a vague and sometimes misused word like “electrolysis” and then ask how any and processes described by that vague word might be used to solve undefined problems :-)
But electrical current can be used to electroplate metals out of wastewater, and electrolysis can be used to oxidize cyanide as described previously in this thread. Determining whether the generation of hydrogen, oxygen, chlorine, and/or caustic by electrolysis has any practical value in wastewater treatment would probably require starting with a scenario where one of those chemicals is perceived to be needed for the treatment. Good luck.
Regards,
Ted Mooney, P.E.
Striving to live Aloha
finishing.com – Pine Beach, New Jersey
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March 19, 2013