Dealing with Waste

[g_axelsson]

So, what part of the waste stream would it go into? The bucket with lead to drop everything prior to treating with lye for disposal?

It depends on how you treat your waste and what material you dissolved. The spent acid will still contain some acid, dissolved lead and tin, iron, nickel, aluminium, zinc... and probably a bunch of other metals.

One way to remove most of the lead would be to add iron sulfate, copperas. The lead would precipitate as lead sulfate and the remaining solution would be less toxic. If you add sulfuric acid instead of copperas you could distill off hydrochloric acid.

There isn't one and only one way to treat waste. You could just simply evaporate the liquid and send the concentrate to a company dealing with waste, leave it on a city collection point with a detailed note of what it contains if you have small volumes, do the whole pH up - down and filter off hydroxides to end up with basically salt water and solid waste... and so on.
It all depends on where in the world you are and other circumstances.

The only thing I know is that I'll not flush any material, solid or liquid, down the drain at my house. My tap water is pumped up just 50 m from the septic tank. Biological toxins have a short lifespan but metals in solution stays forever. The ground below my house is quite permeable, the ground water table moves up and down about 1-2 meters over the year. The infiltrated water will probably flow away from the well but there are other houses downstream from me.

For the small amounts of waste I produce I first extract a dirty copper by cementing on iron (probably some lead and tin mixed in with the solid copper). The resulting liquid is mixed with NaOH until neutral. The hydroxides are mechanically separated and dried. The liquid is put in a plastic pan and the water evaporates over time. This way I reduce the waste to dry waste and very low volume and I leave it at the local recycling center for free.

I'm trying to be frugal in my refining (hi Dave!) so I don't produce too much waste and I cherry-pick the scrap I refine. Some I only stockpile until I find a better method that doesn't produce too much waste. One of my favorite methods is the sulfuric acid reverse plating cell for pins, then I can sell the metal as brass afterwards and doesn't have to mess with any dissolved metals.
Another method that I'm looking at is using cyanide. The same reason to keep down waste.
If I need to denox a solution then I use evaporation, less waste than other methods.
Dissolving gold powder... HCl and strong hydrogen peroxide rather than bleach, no additional solid waste is produced. Everything can be evaporated off. The same is true for aqua regia too.

Göran

 

[Rreyes097]

I've been trying to raise the pH but sodium hydroxide isn't doing anything it seems.

 

[Martijn]

At which pH did you start? Where is it now(pH)?
Where did this waste come from? Which processes, how much of which acids, and did you overshoot any of them?
I found that waste containing H2SO4 takes quite a bit more pH+ (Lye, Soda Ash, limestone powder/ chalk) to even start to get it to rise from pH1.

To raise +\- one gallon of 'normal' waste, I start with one kilo of soda ash in a bucket and filter the cemented waste solution into that bucket, watch the reaction closely, it can "boil" over. Do it in a ventilated area. I pause and filter in between, sometimes twice.
When pH goes over 9, some hydroxides will redissolve, so make sure to filter in between at around that point.


Martijn.

 

[Rreyes097]

It was used AP and ar. I dropped the pms. But now trying to raise it to drop out the iron after I put it in. pH is 0 or below.

 

[FrugalRefiner]

Add more sodium hydroxide.

Dave

 

[Rreyes097]

Ok but it seems as if I've added at least 20+ grams. Maybe way more. Because I put some in a bottle with distilled water and used that too.

 

[Rreyes097]

I just ordered some soda ash. This waste is catching up to me. Although I am letting some evaporate.

 

[FrugalRefiner]

20 grams of NaOH to how much acid??? 100 ml.? 1,000 ml.? A couple of gallons? 20 grams isn't much.

Allowing your waste to accumulate is a very common mistake. Don't let it build up. Process it on the same schedule you refine. If you're creating a liter of waste solution each week, you should be treating a liter of waste each week.

Dave

 

[Rreyes097]

Probably about that much. Plus all rinses! Ice also been doing silver with plenty of rinsing. But what I'm trying to raise the pH in is approximately half gallon? Yeah seems like I turned around and I had 10 gallons of waste looking at me. Well it's being dealt with and properly as well. So no worries. But yeah I'm hitting the brakes on all pm recovery until I'm under 5 gallon of waste. Unfortunately I have 100 grams of silver to precipitate and rinse. And rinse. And rinse rinse rinse! As well as some mylars. B but not many and just wanted to get those out the way while I was already working with silver.

 

[Rreyes097]

Also. Well it's probably pretty vain of me. But I've recovered roughly 14 grams of gold since I've been at it again and still have plenty of CPUs and good plated pins and other stuff to precess. But I was thinking I'd make a gold ring out of the recovered gold and silver. Perhaps a gold ring with an onyx rectangular stone with solid gold legs coming out of it? To look like an ice chip? Or somehow replicate gold fingers? I'm sorry it's of topic. Just wondering if we got any jewelers in the circle.

 

[Martijn]

What I did with my first 7 grams of recovered gold, is a rolling ring hand hammered from a small button.
https://youtu.be/S3Nyso3BapY.
No fancy stones or anything, this was hard enough for me, but lots of fun to do and even more to give to my wife.
Lost wax casting method will be my next try.

 

[butcher]

Nice video, Martijn, The ring looks great, that just gold seems to shine brighter on that pretty little hand you have modelling it in the video, Ill bet she just loves it.

Thanks for sharing your video, and thank you for your support on the forum and helping other members.

 

[Martijn]

Thanks Butcher, I posted it a while ago on the forum. But every now and then other members seem to have the same idea of making a nice ring from self refined gold. So i share ot again. And getting a couple more hits on the video :mrgreen: at 134 hits now... no, it's just for fun.
It makes the gold worth even more imo. And piceless for her. And it sure makes the wife appreciate the hobby a bit more :lol:
Now I'm looking for a jeweller to make wedding bands for us from my own gold and silver which I could never have done without the help of you all. Getting married next year! Finally after 22 years... yeah I know...shame on me :roll:

Love this forum and all you great guys! Sharing is caring :!:

 

[Rreyes097]

I finally got it to 2.5 pH. Let the iron disolve in it for a few hrs. Now it needs to be filtered then that's it?

 

[phoneguy16]

Martijn,

My wife and I have been married for 35 years. In that time we have had 3 "weddings". We think they are all legal, but since 2 of them were in Las Vegas we can't be sure. :lol: What we can be sure of is our commitment to each other. It does not matter what OTHERS think or feel about you, what matters is what YOU and your wife feel about each other. Your commitment of 22 years to each others speaks louder than anything.

Peace to you and your family.

 

[Topher_osAUrus]

Probably about that much. Plus all rinses! Ice also been doing silver with plenty of rinsing. But what I'm trying to raise the pH in is approximately half gallon? Yeah seems like I turned around and I had 10 gallons of waste looking at me. Well it's being dealt with and properly as well. So no worries. But yeah I'm hitting the brakes on all pm recovery until I'm under 5 gallon of waste. Unfortunately I have 100 grams of silver to precipitate and rinse. And rinse. And rinse rinse rinse! As well as some mylars. B but not many and just wanted to get those out the way while I was already working with silver.

Silver is a pretty cruel mistress.

I use an adopted method that gsp suggested at one time. The rinse water from the first rinse of the cement, can be the h20 in the next 50/50 nitric usage on silver. The second rinse, can be used as the first rinse for that next batch. And on and on. I dont go that crazy about it. But, I will reuse rinse water, and try to evaporate as much as possible in between processing of silver batches.

Every little bit of "waste" that can be reused, should be
Save money. Save waste. Save time processing the waste. Save from not having to buy ("new" instead of "used"). Be Frugal. Be Dave.

I really want to start purifying the copper that I've cemented out onto iron in my waste stream. Im sure I would end up recovering some pms from it. ...pgms that didnt cement easily onto copper or whatever reason. (Definitely not from any mistake Ive made... bahaha :shock: :lol: :lol: ) and pure copper to boot. It may not be worth it in the end. ..I think I just like the magic that is, electricity, and chemistry.. and how it all intertwines ..I've been writing a post on a silver crystal thread for a cpl days now. Its far too long.
Not unlike this.

 

[Topher_osAUrus]

Martijn,

My wife and I have been married for 35 years. In that time we have had 3 "weddings". We think they are all legal, but since 2 of them were in Las Vegas we can't be sure. :lol: What we can be sure of is our commitment to each other. It does not matter what OTHERS think or feel about you, what matters is what YOU and your wife feel about each other. Your commitment of 22 years to each others speaks louder than anything.

Peace to you and your family.

6 years, one post
...what was it that made you come out of your shell? :lol:

 

[Martijn]

I finally got it to 2.5 pH. Let the iron disolve in it for a few hrs. Now it needs to be filtered then that's it?

Look at this graph. There are others. You could filter at each lowest point of each hydroxide but at nine and eleven is fine. I do it three times, the first time around 7.

Most of the metals like copper and nickel should have cemented out before raising pH.

Martijn.

@ phoneguy16, thanks. And I agree.

 

[phoneguy16]

@Topher_osAUrus, Perhaps it is because we just celebrated the union of our daughter and I am feeling sentimental or it is just as a wise person one told me you can learn more with your ears than your mouth. I speak when I have something to add, not when I just have something to say.

Thank you.

 

[Rreyes097]

So add iron when it gets to 7? Or the iron already has dropped when it reaches 7? I finally got soda ash and it works so much better then the sodium hydroxide. I've already added the iron for a few hours before I started to raise the pH. So is it my understanding that as I've increased the pH the iron has dropped correct? The liquid looks shiny on the top. But it's otherwise clear. Till you reach the bottom where the metal collected. I want to do this correctly.