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Effluent Characteristic of Cyanide in Electroplating Industry

I want to carry out my research on biological treatment along with adsorption for cyanide discharged from electroplating industries. Which cyanide is produced in most quantities all over world I want to know to prepare my synthetic waste. What is the effluent characteristics of the plating wastewater in which cyanide is in major quantity.

Rajesh Roshan Dash
IIT Roorkee - Roorkee, Uttaranchal, India
2005

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If the waste is treated before it is mixed with other wastes (which would be ideal) it would likely come from cyanide zinc plating, cyanide silver plating, cyanide brass plating, or cyanide copper plating. So, in addition to sodium or potassium cyanide, it would have the corresponding metal dissolved in it, and these metals are also possibly toxic to your treatment biology. Zinc plating is a process where non-cyanide substitutes are enjoying good success, whereas there is simply no substitute on the horizon for cyanide in silver plating. So as time goes by you will see lower zinc concentrations and higher silver concentrations.

The original concentration of the plating baths can be found in most metal finishing texts but would be at least several ounces per gallon. The concentration in the rinse water is very variable, from as high as half the strength of the plating bath to as low as 1/1000 of that.

The law will impede your progress because diluting the waste is against the law in many countries, whereas plants or bugs hardy enough to live in undiluted untreated cyanide-based plating shop effluent is unimaginable.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
2005

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2006

Dear Sir/Madam
Thank you for providing a tools that let me ask my question
I am going to know about role of cyanide in electroplating industry. I do appreciate if you reply me
Best Regards,

Mitra Gholami
Iran University of Medical Sciences - Tehran, Iran

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2005

I don't think if would be practical for you to provide me with an exhaustive explanation of the role of aspirin in medical practice, and neither can I provide an exhaustive description of the role of cyanide in electroplating, Mitra.

But I can give some of the applications:

- Silver plating. There is no practical method of silver plating except from silver cyanide plating baths.

- Brass, white bronze, and other alloys. Different metals have different electrochemical potentials and the only way it becomes possible to plate an alloy is if a complexing agent can reduce the availability of free ions of the more noble metal drastically (by many orders of magnitude). Cyanide complexes the metal to do this, easily and more effectively than any alternatives.

- Plating more noble metals onto less noble metals. Non-adherent immersion deposits can only be avoided by again drastically reducing the concentration of free ions by complexing them, and cyanide is best at this.

- Certain cleaning operations can only be done with cyanide, the world's best cleaner

Progress has been made and is continuing to be made in the reduction or elimination of cyanide in electroplating, but major challenges remain.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey

Sir can you tell me this fact of Zinc in electroplating wastewater. Whether electroplating industries mostly have zinc cyanide or copper cyanide complexes?

rajesh roshan dash
- Roorkee, Indian
2007

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There are far more zinc electroplating installations than copper electroplating installations, and of the jobshops who offer both, most do more zinc electroplating. But there has been a huge swing against using cyanide in zinc electroplating, and it seems like it can be replaced entirely; so I think it would be best to concentrate on silver, and second best would be brass, and third would be copper.

This is a public forum where you interact with readers, Rajesh, and there is nothing more boring to readers than abstract statistics :-)

So please try hard to draw interest by phrasing your postings in terms of what you are doing and why. Thanks!

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
2007

Thank you for your replies.

Rajesh Roshan Dash
- Roorkee, UK, India
January 22, 2009

Is there any industrial biological method to remove cyanide and it's compounds from wastewater? If there is, which companies use these methods?

Amin heidary
student - Turkey
August 4, 2009

Hi, Amin. Cyanide (CN) is a naturally occurring material in such things as apple pips, lima beans, and almonds, so surely some biological agents are able to metabolize it -- presumably converting it to nitrogen and carbon dioxide as the chemical approaches do.

But cyanide is also a very powerful poison, so I think it is unlikely that any biological agents can even survive in CN in the concentrated form it is found in plating waste, let alone metabolize it. You might think therefore than the answer is dilution before biological treatment, but in many jurisdictions it is illegal to dilute plating wastes for treatment; the law of unintended consequences has inadvertently outlawed this promising approach to treatment of CN waste :-(

Regards,

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
September 2009

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Sir, I'm interested to know the concentration of heavy metals in the waste water produced from the electroplating industry and also want to know what should be the concentration of heavy metals in water which is to be discharge from electroplating industry by Indian standards.

i am pursuing M.Tech from IT-BHU and in my project I have to study on heavy metals from industries so please do a favour to help me in my project work.

garima mishra
electroplating - India(IT-BHU)
September 15, 2009

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Hi, Garima. The first half of your question was sort of answered already: Plating shops use solutions that are generally several ounces per gallon in concentration, and are detailed in texts like The Metal Finishing Guidebook and the Electroplating Engineering Handbook [on AbeBooks or eBay or Amazon affil links] . These solutions are rarely, but occasionally dumped. The larger volume is from rinsing off the ware with water, and the concentration of this waste water can range from half of the plating bath concentration to about 1000th of the original concentration. You could reasonably estimate for statistical purposes that the concentration of the waste before treatment is in the high 1 digit ppm to low 2 digit ppm (6 to 30 ppm would be a believable number for a hypothetical plating shop).

I don't know the Indian discharge standards, and there may be local standards by city or province, but they are probably in the 0.1 to 2.0 ppm range for various metals. You need to get the numbers from the regulatory body. Good luck.

Regards,

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
September 21, 2009