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How should the acids and lye used during home anodizing be disposed?

1999

Q. I am interested in anodizing some small aluminum parts and have some questions on how to deal with the acids and lye when I am finished.

I will have 3 gallons sulfuric acid (made up from 1.5 gallons of battery acid ⇦ this on eBay or Amazon [affil links] and 1.5 gallons of distilled water) and a gallon of 10% nitric acid solution. Can these be neutralized with baking soda? How should they be disposed? I will be using a lead cathode in the sulfuric acid. will the sulfuric acid become contaminated with lead?

I will also have a gallon of lye made up from 6 tablespoons of red devil lye? Since the red devil lye is sold as a drain cleaner is it safe to pour it down the drain?

[Ed. note: name and e-mail address were removed based on replies below]
Baton Rouge, Louisiana

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1999

Hi!

I've done some anodizing, and according to the plating manual that I have, it should be neutralized with baking soda [in bulk on eBay or Amazon [affil links] before dispose it. It looks okay; some time ago, I bought a drain opener at a local hardware,and it says on the label to neutralize it with baking soda after having the drain unclogged, It's 98% sulfuric acid (far more acid than we use). Questions like yours should be welcome.

I wish there was some article about acid disposal for plating as a hobby.

Just do it if you really know what you are doing, and take all the necessary precautions.

One thing comes in mind: what about the possible millions of people that use the same drain opener that I've bought? With far more acid concentration than we use for non commercial anodizing process? What about the millions of people that uses bleach as a daily cleaning solution all around the house?

I'm not saying that it's okay to dump your acid solution down the drain after every use, just put it back in a well sealed container after the use of it. I've started anodizing two years ago,and I'm still using the same solution.

One thing that I've noticed is that you have to somehow control the temperature on the acid tank,in other ways to cool it,because anodizing generates heat and you need to remove it.I'm trying to find a inexpensive way to keep the tank cool, somebody recommended to try dry ice and copper coils,I've being thinking about take apart a dehumidifier and maybe rout a copper coil in between the evaporator, well I don't know what I'm going to do yet. Maybe use an aquarium chiller -- it's about $500

Hope it helps.

[name deleted]
Bridgeport, Connecticut

Ed. note: name and e-mail address removed based on comments above and below.