Simple scrubber bucket design

[fishstick]

I've been refining as a hobbyist for 5+ years. I usually just do my work outside when the weather is nice but recently have wanted a small set up in my garage. So I devised my bucket scrubber!

It's a small scale scrubber for occasional use in my garage and I have been using with decent results. I'm in the process of updating the vacuum to a more potent suction source since I just used a cordless vac to start. The whole thing can be built for approximately $80-$100 and maybe even less depending on what you have on hand. The basics - I used a 5 gallon bucket, cordless vac, 100 PSI water pump, tubing and some misc PVC pipe. I took advantage of nitrogen dioxide's solubility in water by using a spray/mist nozzle to introduce to the gas being sucked into the bucket by the vacuum source. For the water, I fill the bottom of the bucket and this is used both a source and collection reservoir. Once I'm completed with the reactions - I neutralize the scrubber bucket contents to a pH of 8-10, which is safe for the material to be dumped down the drain.

Note.....I refine gold and silver in small quantities (ex. I use between 200 - 400 ml of HNO3 per batch) so this would need to be magnified for larger scale use.

 

[jeneje]

Once I'm completed with the reactions - I neutralize the scrubber bucket contents to a pH of 8-10, which is safe for the material to be dumped down the drain.

Dumping neutralized toxic solutions down the drain is not a good idea. They really need to be sent to a waste treatment place. I don't know your situation, but, if you live in a place that has city water and sewer this would not be good. Even in the country I would not want to just dump it.

Ken

 

[Westerngs]

Dumping neutralized toxic solutions down the drain is not a good idea. They really need to be sent to a waste treatment place. I don't know your situation, but, if you live in a place that has city water and sewer this would not be good. Even in the country I would not want to just dump it.

Ken

Hi Ken,

Please explain your rationale for the statement above. I may or may not agree with you depending on your rationale.

Thanks.

 

[jeneje]

Dumping neutralized toxic solutions down the drain is not a good idea. They really need to be sent to a waste treatment place. I don't know your situation, but, if you live in a place that has city water and sewer this would not be good. Even in the country I would not want to just dump it.

Ken

Hi Ken,

Please explain your rationale for the statement above. I may or may not agree with you depending on your rationale.

Thanks.

Be glad too. First, if you are on a City water system all those solution end up at your local water treatment plant for processing back into the drinking water you use. Second, if you live in the country and just pour out the solutions they will end up in the water table you and your neighbors get your water from.

Alkaline solution above Ph7 can cause damage to your plumbing the same as acidic solutions can. If pouring them outside the alkaline base can kill vegetation and animals if they come into contact with it, depending on how saturated the ground becomes.

And finally, it just not very responsible, if a person is going to pour solution down the drain or outside as so many of us do, they need to make sure they are safe to do so. 4metals has a post here in the safety section i think for waste disposal, it explains in detail how to treat your solution to make them safe for all.

So, that is my rationale for the statement I posted.

Thanks,

Ken

 

[rickbb]

He also does not state that he, (or she), checks for and/or removes any metals that may or may not be precipitating out of the waste solution.

Just adjusting the PH alone is all that is stated, and that does not in any way render it safe for disposal.

 

[jeneje]

He also does not state that he, (or she), checks for and/or removes any metals that may or may not be precipitating out of the waste solution.

Just adjusting the PH alone is all that is stated, and that does not in any way render it safe for disposal.

There is also NO mention of the hydroxides either or what he/she done with them. This is some of the stuff that the beginner's don't take into account when wanting to recover/refine precious metals. As Rick said -- just because it has a Ph of 7 does not mean it is SAFE to do with what you want. Sometimes you need make for sure to protect yourself and your environment around you.

Ken

 

[4metals]

I think you guys are confusing the waste associated with the refining acids with the waste scrubber liquids. The OP is speaking of scrubber liquid. Unless you have a problem with sucking in excessive solution from your reactions, you should have no problems with excessive heavy metals in your caustic liquors. So talk of metal hydroxides is moot in the case of a well functioning fume scrubber.

As the OP states a pH of 8-10 is required for discharge down the drain. He/she obviously lives in an area where there is water treatment because that pH is a bit on the high side for septic discharge. I would prefer to lean towards the 8 end of the specification, or even better neutral at 7.

In any event the sodium hydroxide will end up as a nitrate salt when the NOx fumes react with it and the waste will be rather tame in comparison to the waste generated by refining. My posts in the Waste Treatment thread in the safety section are aimed at refining waste acids.

 

[jeneje]

I think you guys are confusing the waste associated with the refining acids with the waste scrubber liquids.

You are right, I was . I apologize for mis reading the OP. I was thinking he was pouring out the spent reaction solution. Thank you for clearing that up.

Ken

 

[fishstick]

Indeed, I was referring to the "scrubber bucket contents" as the post was relating to scrubber design. I see lot's of questions on the board about this topic and have seem some very elaborate ones built. Just wanted to pass on the information on mine since it seems reliable (so far) for small scale. If anyone wants to see pics I can get try and get some posted after I get back from vacation.

Oh and just a tid bit since my topic kind of veered to waste treatment. I do manage my reaction wastes appropriately. While I'm not an expert, I've been refining as a hobbyist for years and also have a Doctor of Pharmacy degree and am knowledgeable of safe practice/chemistry. Also, I work with a PhD chemistry professor from my alma matter (who actually helped with my scrubber design) about safe disposal and am even looking at ways to possibly recover useful fertilizer from various reactions. But as stated I'm a hobbyist - so my volumes are quite small.

 

[kurtak]

Pictures are "always" nice so hope to see some when you get back home

Kurt