upcyclist
Well-known member
I tend to use hydrated lime (calcium hydroxide), because it's readily available from hardware/farm stores and cheap. I suspect it creates a higher volume of sludge, though, than some of the other hydroxides.
Dealing with Waste
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Topher_osAUrus
Well-known member
upcyclist said:
I just started using slaked lime/hydrated lime too
The garden store stuff is cheap, i paid 11 dollars for 10lbs, and I like it a lot more than NaOH. The sludges settle faster, and, it also does more neutralizing work than the lye since it is Ca(OH)2.
Overall, I like it.
The slaked lime, plus the wick filter system, makes waste treatment a breeze.
I think I read somewhere on here that it had its drawbacks, but I cant find that post, and I have no negatives of my own to post on it.
So, overall it's good stuff!
Nice 
Higher volume aren't that important for me.
I'm planning to dry it to powder and hand it over dry.
What counts, is if it settles properly so I can get sufficient liquid out of it to let it air dry in decent time.
When using NaOH it seems like it settles in two fractions.
One relatively fast course and a fluffy gel like fraction that almost does not settle at all.
I have to admit I haven't used much Ph control on it yet.
BR Per-Ove
Higher volume aren't that important for me.
I'm planning to dry it to powder and hand it over dry.
What counts, is if it settles properly so I can get sufficient liquid out of it to let it air dry in decent time.
When using NaOH it seems like it settles in two fractions.
One relatively fast course and a fluffy gel like fraction that almost does not settle at all.
I have to admit I haven't used much Ph control on it yet.
BR Per-Ove
The next time you have a wick filter going on please take a few pictures and post them.
Topher_osAUrus
Well-known member
4metals said:
I kept it as simple and cheap as possible.
Instead of cloth, I use a rope. I have tried a couple different types. But, i like this one the best.
I tie a knot on one end, big enough so it wont slip through a 2inch diameter piece of pvc (about 6 inches long). The pvc acts as my "anchor" so the rope stays on the bottom of the bucket.
[Sorry, didn't get a pic of it, it was already submerged]
As far as the rest goes. The waste bucket is a 5gal thats 2/3rds full. Sitting angled in an empty bucket, with the rope hanging over into an empty bucket.
(The overhead pic was as I transfered the rope and pvc from anotger bucket, the water drips clear, thats sludge from the transfer that dropped in)
Takes a couple days to get to the bottom of the sludge, but, its about the best way to do it (short of a filter press)
The sludge is scooped into a smaller 3.5 gallon bucket and left to bake in the 105 degree sun to dry out completely.
As far as the initial waste treating steps. The blacks cemented onto copper are saved in a jar until its full.
The copper is cleaned, dried, and saved. So i can either use it to cement more metals with, or eventually melt some anodes out of it, to be ran through a copper cell.
Edit to add
Attachments
To understand this technique a little better, the nasty looking thick green black liquid sludge is acid waste after cementation with copper, that has been raised to a higher pH to drop all of the metals as hydroxides. Did you use sodium hydroxide (drain cleaner) and what pH did you stop at?
The liquid that travels through the rope comes out clear (picture please) and the sludge is dried out in the sun.
And a 5 gallon pail filled 2/3 (or 3.3 gallons) passes through the rope in about 2 days if left undisturbed.
Do you feel you could get it to filter faster if you hung more strands of rope into the same PVC pipe anchor?
For a hobby refiner, that's a darn sight cheaper than buying a filter press!
The liquid that travels through the rope comes out clear (picture please) and the sludge is dried out in the sun.
And a 5 gallon pail filled 2/3 (or 3.3 gallons) passes through the rope in about 2 days if left undisturbed.
Do you feel you could get it to filter faster if you hung more strands of rope into the same PVC pipe anchor?
For a hobby refiner, that's a darn sight cheaper than buying a filter press!
Topher_osAUrus
Well-known member
It has served me well thus far. I thought about just making it all ferric chloride and having a waste company pick it up...4metals said:To understand this technique a little better, the nasty looking thick green black liquid sludge is acid waste after cementation with copper, that has been raised to a higher pH to drop all of the metals as hydroxides. Did you use sodium hydroxide (drain cleaner) and what pH did you stop at?
On that bucket, I cemented with copper, siphoned to a new bucket, placed in iron. After that, siphoned to a new bucket,
used NaOH til pH 9, added HCl to 7 then threw in the rope (the slime is from the bucket I moved it from, see pic below)
Do you believe I should have left it on the iron for longer? In loewens book, he suggests adjusting to ph 2 or 2.5 before going to the iron stock pot. Thoughts on that? (I only ask because some of his writings are iffy at best...like saying to just dump the ferric chloride as is, down the drain..
I have just recently started using slaked lime. Do I need to do anything different as far as pH range and adjustment goes to abide by safe waste standards?
This is my sludge bucket, it has quite a bit of moisture right now, as I scoop as all I can, then use a rinse bottle to squirt the remainder into here
The liquid that travels through the rope comes out clear (picture please) and the sludge is dried out in the sun.
And a 5 gallon pail filled 2/3 (or 3.3 gallons) passes through the rope in about 2 days if left undisturbed.
That picture above isnt the best, there is maybe a couple hundred mL in there, but it's only been running for an hour at most
Do you feel you could get it to filter faster if you hung more strands of rope into the same PVC pipe anchor?
Actually, yes, it goes significantly faster (about twice,
actually :roll: ) if I double the rope up, but, I forgot I was down to my last length and need to get more to double it up, I may even live on the wild side, and try 3 strands. :shock:
For a hobby refiner, that's a darn sight cheaper than buying a filter press!
But, they are very proud of their services (expensive!!$$!!)
Edit to fix spelling.
Loewen's book was written a while ago and he did mention there was no discharge limit for iron in wastewater at the time he published the book in the state he was refining. (Which I believe was Texas)
I always preferred to raise the pH a bit before the iron was added as it made the metals come out a bit more granular than if it was raw acid. And the metal in the sludge is directly dependant on what was dissolved in there to begin with. With karat gold refiners (which Loewen was) that made a liquid with mostly copper in it so it cemented a metal high in overall copper content. But that also left zinc behind. Raising to a pH of around 10 maximized the zinc that comes out as a hydroxide. That liquid, filtered free of solids was neutralized and tested for discharge.
Filtering hydroxides is always slow and messy. A filter press makes short work of it but will also drain your wallet when you go to buy one.
With your rope method, adding a few strands of rope and fraying the clean dripping end you can likely get up towards 5 gallons a day of filtered hydroxides. For a hobby refiner 35 gallons of waste a week is a lot.
It would be helpful for you to post photo's of the dried high copper content powder you produce from adding iron and a photo of the dried metal hydroxide sludge after the wick filtration and drying as well.
I always preferred to raise the pH a bit before the iron was added as it made the metals come out a bit more granular than if it was raw acid. And the metal in the sludge is directly dependant on what was dissolved in there to begin with. With karat gold refiners (which Loewen was) that made a liquid with mostly copper in it so it cemented a metal high in overall copper content. But that also left zinc behind. Raising to a pH of around 10 maximized the zinc that comes out as a hydroxide. That liquid, filtered free of solids was neutralized and tested for discharge.
Filtering hydroxides is always slow and messy. A filter press makes short work of it but will also drain your wallet when you go to buy one.
With your rope method, adding a few strands of rope and fraying the clean dripping end you can likely get up towards 5 gallons a day of filtered hydroxides. For a hobby refiner 35 gallons of waste a week is a lot.
It would be helpful for you to post photo's of the dried high copper content powder you produce from adding iron and a photo of the dried metal hydroxide sludge after the wick filtration and drying as well.
Topher_osAUrus
Well-known member
As you wish sir, I will have a better picture of my sludge tomorrow, and the copper as well. Finishing up some gold tonight or tomorrow morning and then its all waste treatment until next mondays move. Yay!4metals said:
rewalston
Well-known member
Topher_osAUrus said:
Topher what kind of rope is that, if you don't mind my asking.
bigpagoda
Well-known member
I use a similar 11mm cord made of polyester that I bought in the sewing section at walmart 90 ft for 6$.
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Wow Polyester works?
Darn you learn something new everyday. Thanks bigpagoda.
Darn you learn something new everyday. Thanks bigpagoda.
Topher_osAUrus
Well-known member
Yep, thats what it is.
Although, I am starting to like it less and less.
After starting another bucket with the same rope/pvc setup, it began to drip some particulate in with the clean water. Could be that it got over because I transfered it poorly, but I cannot say for sure.
I will have to try to be more careful on the next one
Although, I am starting to like it less and less.
After starting another bucket with the same rope/pvc setup, it began to drip some particulate in with the clean water. Could be that it got over because I transfered it poorly, but I cannot say for sure.
I will have to try to be more careful on the next one
When I'm heating and bending PVC, I like to fill it with fine sand packed in tightly and capped. It keeps the tubing from collapsing when you bend it. Fumes can be nasty so use good ventilation.
Dave
Dave
upcyclist
Well-known member
Very slick!snoman701 said:
Heck, I know some stores are already hawking Christmas stuff (I'm looking at you, Hobby Lobby). There might be some candy-filled canes (I remember the old M&Ms candy canes) you can ::ahem:: empty and reuse. As long as everyone hasn't gotten so cheap they're using paper-thin plastic.
tinman1472
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Not to beat a dead horse or anything. But I am a new member and I have been reading through this post and many others regarding waste treatment and disposal. There seems to be some conflicting information about the disposal of the final waste products in this thread, neutral ph liquid and iron hydroxide. I have read from some people that the iron hydroxide is considered hazardous by the epa, but I couldn’t find anything from the epa that said that.
Do both the liquid waste and the iron hydroxide get sent to a non hazardous waste facility for treatment? Or is something different done with the iron hydroxide? Of course after a test to make sure they are under epa regulated concentration of metals.
Do both the liquid waste and the iron hydroxide get sent to a non hazardous waste facility for treatment? Or is something different done with the iron hydroxide? Of course after a test to make sure they are under epa regulated concentration of metals.
Martijn
Well-known member
Gents, I have a question about the waste treatment of the sulfuric cell. I am familiar with raising the ph of the wash water with soda ash or NaOH to cement on iron after cementing in the stock pot on copper.
I usually separate the hydroxides in two steps (>Ph 6 and >Ph 11) and save them to experiment later on in an electro-winning process, getting the waste to a minimum.
I usually siphon off the clean sulfuric and reuse that in a new cell, but now i have poured the whole (300ml) of 96% sulfuric containing the gold in two 2 liter beakers and further rinsing of the powder brought it up to 6 Liter. Added to this solution are some leftovers from Nitric digestions & cementing on copper. It's about 10L in total now.
Before adding the copper nitrate waste to the waste pot i got a bit AgCL out of that batch by adding HCL 30% in small steps of 2 ml at a time. Stopped when no chlorides formed anymore by adding HCL. There wasn't much free nitric left after cementing, only a little silver re-dissolved while cementing.
Now i guess this solution contains so much sulfuric that it has reached the saturation point of soda ash, since added soda ash won't dissolve anymore and the Ph is still 1 I have added a bit of NaOH to see if that will dissolve, and it does. PH remains 1, so still a long way to go?
So there is 300ml of sulfuric to which i have added about 2 kilo's of soda ash. i can't find the saturation point of soda ash in acidic water. I can imagine it's depending of whats in the mix.
How much soda ash does it take to neutralize say 100ml of sulfuric? the total amount of water makes less of a difference, i can imagine. It would still have to neutralize a certain amount of acid.
Can i continue to add NaOH to neutralize the acid or do i need to dilute the solution so i can continue with soda ash?
Hope someone can help me out with this.
I usually separate the hydroxides in two steps (>Ph 6 and >Ph 11) and save them to experiment later on in an electro-winning process, getting the waste to a minimum.
I usually siphon off the clean sulfuric and reuse that in a new cell, but now i have poured the whole (300ml) of 96% sulfuric containing the gold in two 2 liter beakers and further rinsing of the powder brought it up to 6 Liter. Added to this solution are some leftovers from Nitric digestions & cementing on copper. It's about 10L in total now.
Before adding the copper nitrate waste to the waste pot i got a bit AgCL out of that batch by adding HCL 30% in small steps of 2 ml at a time. Stopped when no chlorides formed anymore by adding HCL. There wasn't much free nitric left after cementing, only a little silver re-dissolved while cementing.
Now i guess this solution contains so much sulfuric that it has reached the saturation point of soda ash, since added soda ash won't dissolve anymore and the Ph is still 1
I have added a bit of NaOH to see if that will dissolve, and it does. PH remains 1, so still a long way to go?So there is 300ml of sulfuric to which i have added about 2 kilo's of soda ash. i can't find the saturation point of soda ash in acidic water. I can imagine it's depending of whats in the mix.
How much soda ash does it take to neutralize say 100ml of sulfuric? the total amount of water makes less of a difference, i can imagine. It would still have to neutralize a certain amount of acid.
Can i continue to add NaOH to neutralize the acid or do i need to dilute the solution so i can continue with soda ash?
Hope someone can help me out with this.
Why neutralize an acid that can be re-used to dissolve more unwanted base metals...
I try to re-use most of my waste as much as possible before treating it, many times I find other uses for my waste, or I can make something else useful out of it.
I dry all of my solid waste (iron hydroxides) and roast it to oxides before disposal, the saltwater is evaporated and the salt dried before disposal,
View attachment Neutralization-chart.pdf
I try to re-use most of my waste as much as possible before treating it, many times I find other uses for my waste, or I can make something else useful out of it.
I dry all of my solid waste (iron hydroxides) and roast it to oxides before disposal, the saltwater is evaporated and the salt dried before disposal,
View attachment Neutralization-chart.pdf
Martijn
Well-known member
Butcher, thanks for the option of reuse and the neutralization chart. It's another gem to add to my collection.
To explain: I wanted to finish my sulfuric stripping cell because the plated items are done and i wanted to get all of the gold. The acid in the cell had turned completely black and I thought it might hold gold suspended in solution, not only on the bottom. i didn't think about reusing the wash water, just "dealing with waste" responsibly.
I guess boiling the wash water down to more pure acid would have been the way to go? If i had not treated it with soda first...
And thinking about it, i could have reused it for electro-winning, dissolving the hydroxides to make the electrolyte. Can it still do that now there are metal nitrates, metal chlorides and the dissolved soda in solution? It will also hold some free nitric and HCL that would be boiled off, if i'm correct. I don't want to complicate things even more. I have enough fresh sulfuric for that.
Are there any other uses for spent sulfuric from the gold stripping cell other than digesting base metals? And is sulfuric often used for that? it would still be quite full of base metals, so only "dirty"digestions would be an option?
Another thing puzzling me; calculating the amount needed to get the Ph of the sulfuric in solution (+\-300ml in +\-10L) to at least rise from 1 would be about 0.6 kilogram of soda ash, (300 ml with a specific gravity of 1.8g/ml gives .54 kilo of acid, with the pound per pound ratio of 1.06, gives 0.57 kilo of soda) it should have done that long ago. I've added 2 kilo, and there's a couple ounces left undissolved. I decanted the solution from this soda sediment.
Any reasons why it is taking so long? Is it the mix with nitrates and chlorides? The copper nitrate should be mostly gone after cementing, does that leave any free nitric in solution or is all nitric set free by cementing reused forming iron nitrate in the cementing process?
What would you recommend how to proceed? Evaporating the waste water and store it for experimenting and other uses? It will continuously precipitate more soda while evaporating, because the saturation level is reached, right?
If reuse is not an option anymore in my case, i think calling it a loss and treating it as waste would then be the next best option. if that's the case, can I use NaOH to raise the Ph or does the level of soda in solution prohibit that? Diluting it with water would only increase the amount of wastewater. And hoping it will not take another 2 kilo of soda or more. I don't want a lot of buckets sitting in my shed.
So many questions, i know, but i can't find the answers to my specific problem.
Martijn.
To explain: I wanted to finish my sulfuric stripping cell because the plated items are done and i wanted to get all of the gold. The acid in the cell had turned completely black and I thought it might hold gold suspended in solution, not only on the bottom. i didn't think about reusing the wash water, just "dealing with waste" responsibly.
I guess boiling the wash water down to more pure acid would have been the way to go? If i had not treated it with soda first...
And thinking about it, i could have reused it for electro-winning, dissolving the hydroxides to make the electrolyte. Can it still do that now there are metal nitrates, metal chlorides and the dissolved soda in solution? It will also hold some free nitric and HCL that would be boiled off, if i'm correct. I don't want to complicate things even more. I have enough fresh sulfuric for that.
Are there any other uses for spent sulfuric from the gold stripping cell other than digesting base metals? And is sulfuric often used for that? it would still be quite full of base metals, so only "dirty"digestions would be an option?
Another thing puzzling me; calculating the amount needed to get the Ph of the sulfuric in solution (+\-300ml in +\-10L) to at least rise from 1 would be about 0.6 kilogram of soda ash, (300 ml with a specific gravity of 1.8g/ml gives .54 kilo of acid, with the pound per pound ratio of 1.06, gives 0.57 kilo of soda) it should have done that long ago. I've added 2 kilo, and there's a couple ounces left undissolved. I decanted the solution from this soda sediment.
Any reasons why it is taking so long? Is it the mix with nitrates and chlorides? The copper nitrate should be mostly gone after cementing, does that leave any free nitric in solution or is all nitric set free by cementing reused forming iron nitrate in the cementing process?
What would you recommend how to proceed? Evaporating the waste water and store it for experimenting and other uses? It will continuously precipitate more soda while evaporating, because the saturation level is reached, right?
If reuse is not an option anymore in my case, i think calling it a loss and treating it as waste would then be the next best option. if that's the case, can I use NaOH to raise the Ph or does the level of soda in solution prohibit that? Diluting it with water would only increase the amount of wastewater. And hoping it will not take another 2 kilo of soda or more. I don't want a lot of buckets sitting in my shed.
So many questions, i know, but i can't find the answers to my specific problem.
Martijn.
