Re: gEDA-user: Disposing of Etch Solution
Yes, it's very easy to make H2O2 decompose. Activated carbon does it very quickly, but charcoal works too. Just don't use charcoal briquettes imbued with lighter fluid!. And if your sink is getting damaged, I would guess that the problem is too much base, not too much H2O2. Strong bases can etch stainless steel. And yes DJ is correct that the copper precipitate would be hazardous waste. When I first replied to Rob, I thought that he meant "surplus" solution, not "used" solution. On Thu, Jan 20, 2011 at 10:19 AM, Mike Bushroe wrote: > I have excess muratic acid/hydrogen per oxcide etch solution after > making a > board. What is an acceptable way to dispose of it? > > The hydrogen peroxide > is easy to neutralize; just put a piece of charcoal in the bottle > and > it should decompose. First pour water into a container, then > mix in a calculated amount of base, then slowly pour in the acid. I > don't know the relevant environmental regs, but I'm sure that at pH > 5-9 those chemicals should be safe for any sewer. > > I had not heard about using charcoal to neutralize the H2O2, I will try > that int he future. When I have dumped old muriatic (hydrochloric) > acid/hydrogen peroxide, I first sprinkle baking soda or pool soda ash > in until it stops foaming, then pour down the sink and rinse well. > However, this tarnishes the stainless steel sink, so obviously I have > not yet fully neutralized it. Next time I will start with the charcoal. > Mike > > > > ___ > geda-user mailing list > geda-user@moria.seul.org > http://www.seul.org/cgi-bin/mailman/listinfo/geda-user > > ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: Disposing of Etch Solution
I have excess muratic acid/hydrogen per oxcide etch solution after making a board. What is an acceptable way to dispose of it? The hydrogen peroxide is easy to neutralize; just put a piece of charcoal in the bottle and it should decompose. First pour water into a container, then mix in a calculated amount of base, then slowly pour in the acid. I don't know the relevant environmental regs, but I'm sure that at pH 5-9 those chemicals should be safe for any sewer. I had not heard about using charcoal to neutralize the H2O2, I will try that int he future. When I have dumped old muriatic (hydrochloric) acid/hydrogen peroxide, I first sprinkle baking soda or pool soda ash in until it stops foaming, then pour down the sink and rinse well. However, this tarnishes the stainless steel sink, so obviously I have not yet fully neutralized it. Next time I will start with the charcoal. Mike ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: Disposing of Etch Solution
> Do you mean muriatic acid and hydrogen peroxide? Those are not > hazardous chemicals, Used etchant is *always* hazardous waste, because it contains copper, which is toxic. ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: Disposing of Etch Solution
The whole point of HCl/H2O2 solution is that you *dont* have to discard it. Over time, it grows into a CuCl etchant which is air regenerated and shelf stable. Otherwise, mix NaOH slowly until the solution turns from clear green to opaque white. Let the water evaporate, bring the remaining copper salt cake to hazardous waste disposal. ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: Disposing of Etch Solution
Do you mean muriatic acid and hydrogen peroxide? Those are not hazardous chemicals, if they are neutralized. The hydrogen peroxide is easy to neutralize; just put a piece of charcoal in the bottle and it should decompose. Exposing it to sunlight will also work. Muriatic acid could be harder, depending on the concentration. You just need to react it with base. Sodium bicarbonate, ammonia, and powdered drain cleaner are all readily available bases. But if the acid is highly concentrated, you will need to mix carefully because the reaction is exothermic. First pour water into a container, then mix in a calculated amount of base, then slowly pour in the acid. I don't know the relevant environmental regs, but I'm sure that at pH 5-9 those chemicals should be safe for any sewer. Are the muriatic acid and H2O2 already mixed together? I don't think that H2O2 has an adverse reaction with most bases. NaOH will probably just catalyze its decomposition. But IANAC (I am not a chemist). On Thu, Jan 20, 2011 at 9:43 AM, Rob Butts wrote: > I have excess muratic acid/hydrogen per oxcide etch solution after > making a board. What is an acceptable way to dispose of it? > > > > Thanks > > > > ___ > geda-user mailing list > geda-user@moria.seul.org > http://www.seul.org/cgi-bin/mailman/listinfo/geda-user > > ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
gEDA-user: Disposing of Etch Solution
I have excess muratic acid/hydrogen per oxcide etch solution after making a board. What is an acceptable way to dispose of it? Thanks ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
