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Dealing with Solid Carbonates from Cadmium Cyanide Plating Bath

We operate a plating shop including Cadmium Cyanide plating.

We have recently emptied one of our plating baths and we are left with quite a substantial layer of hard carbonates in the bottom of the tank which we need to remove.

I am fully aware that this solid will contain both Cadmium and Cyanide in significant quantities, so there are obviously safety concerns in tackling his problem.

I would appreciate any advice regarding the solution to this problem.

Thank you in advance,

Jonson Brennan
Aerospace Plating and Anodising - Isle of Man, United Kingdom
2006

If you have a waste water treatment system, you may redissolve the precipitate in warm water and then treat it as you would liquid waste. The simpler alternative is to have the material removed, after being placed in the appropriate container type, by a waste hauler for destruction,disposal or recycling (I am afraid I am not cognizant of the requirements for waste hauling or disposal in the UK. In the U.S. a firm must be licensed and/or permitted to perform those functions)

Gene Packman
process supplier - Great Neck, New York
2006

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Glad to see someone still plating cadmium but it suffers from a bad press.
UK legislation makes even thinking about cadmium a nightmare. The first thing you will need will be a 'suitable and sufficient' risk assessment for the entire operation. Without that any glitch will bring HSE and ED down like a tonne of bricks. That is the simple bit. Do you have IPPC approval for cadmium? What is the size of the problem - grammes or tonnes? Why do you need to disturb it? If it is hard and not adding particles to the solution, the simplest option is to ignore it - if it is not broke, don't fix it. Refill the tank, fit a good filter pump and press on. If the tank is unusable in its present state, it may be worth considering disposing of the entire tank rather than try to dig it out - it could be the cheaper option.
Hope this helps.

Geoff Smith
Hampshire, England
2006