What do you use for a stock pot?

What kind of a vessal do you guys use for a stock pot? What have you found to work the best?
I just want some opinions.
So far I have only used Hcl, Sulfuric Acid, hydrogen peroxide, Clorox, SMB and Oxalic acid. (Not all at once of course )
Would a 5 gal plastic bucket work?

That's what I use and have used for years. I have read that some people use much smaller containers but I like a 5 gallon pail.

aj

I use plastic the plastic bucket, and canning jars (with peanut butter plastic lids) for small lots.

Sometimes I have several stock pots, the general for large batches of solution with trace values, small higher value stock pot (PGM), silver stock pot...

Sometimes even one recovery/refine (like when working with a batch of dental gold) will have its own small stock pot, for holding undissolved values and traces, or solutions gathered later in the process, this stock pots solutions after cementing and cleaning up... will be put into the larger more general stock pot, the metal and powdered remains are saved to be treated later in another process or added to another process later.

I have 2 crock pots. I so far only do gold so it starts in 1 crock with copper in. The 2nd pot has steel in. I let sit for as long as I can and then on to the 5 gal. bucket for PH adjustment.

I've read 2 different views on dropping copper.
1. just put steel in and let sit... This has worked for PC steel like from floppy drive holders. but I have steel shavings from brake rotors...They resurface them to put new brakes on for older cars... but doesn't seem to drop much copper.
2. Raise PH and then put steel in.

Then onto bucket to raise PH high enough to drop steel.

My question would be raise PH and put steel in or steel and them move to raise PH?

B.S.
...It's really tough keeping things straight in my scrambled brain sometimes...

I use steel turnings from the scrapyard to drop the silver from nitric acid after i run my gold filled. Did you incinerate the turnings to eliminate any oil residues? I use to have problems before i started incinerating the shavings.

When I precipitate copper from solution with iron or steel, I do not raise pH before hand, iron can form hydroxide easily and leave rust with the copper metal powder, other metals precipitate as hydroxides as pH is raised, the iron will use up free acid as copper metal precipitates out of solution the iron will form Iron salts (FeCl3 for example) salts of metals are less acidic than the acids used to form them, although many of these metal salts can be acidic or very corrosive themselves.

After all of the metals that will come out of solution that can, while iron goes into solution, I will remove settled copper (and other metals) then adjust pH of solution, if I have Hydroxide waste saved from another process I can use this, I can use a variety of chemicals, NaOH is one of the strongest, But I will also use others even hard wood ashes, to bring the pH up to about 9.5 this is where most metals will precipitate as oxides/hydroxides. Let sludge settle decant salt water from sludge, lower the pH of solution back down to pH7 with acid, if the solution was chlorides this leaves a salt water solution, I have a septic tank so I evaporate the solution to salt.

The sludge is very slow to dry, and with it raining or snowing all winter, this is a summer long project for me, putting rag in a 5 gal. Bucket on end to the inside of the bucket to the bottom, the other end of the rag hags outside the bucket, the bucket is tilted and braced at an angle, the end of the rag hangs over a catch bowl or bucket, where the capillary action pulling moisture drips salt water from the rag into the catch bowl, when sludge becomes closer to dry its damp mud is shoveled to one side of the bucket attempting to give air exposure to the mud in the bottom of the bucket where possible, as it dries more shoveled around more, when dry enough but not completely dry the bucket is poured out into a large fiberglass tub, cut with a shovel to separate as much as possible, and allowed to sun dry, as it dried it is broken apart and crushed to powders, after dry it is returned to a bucket with a lid, in winter this dry metal hydroxide powder is roasted in pans over coals from slash fires to change the soluble hydroxide powder to a less soluble metal oxide powders, after cooling are bagged and packed for disposal.

Read dealing with waste, situations to avoid, and the elephant in the room, found in the safety section, these do an excellent job of explaining how to deal with waste, you can carry the study further finding charts of at what pH each metal precipitates as hydroxide, and how industry deals with waste solutions and sludge...

That's what I thought through my pots as they are.
And thanks, I propably need to incinerate the turnnings beforehand. Being a mechanic for too many years, I should have known they are to dirty as they are.

My first round waste was less then a gal. which was trippled in size with wash water. I went through a 2.5lb. pool PH stabilizer Baking Soda, same as food brand but larger bag look in pool dept. at local stores, and the PH was still low.
I have since gotten a nice "Chimnea", pottery fireplace, that will work great for pyrolizing and incineration so there's plenty of ashes to go with. I had a nice 4 foot flame shooting out of the top of it which is good for off gasses. Pics and details when I get the details figured out.

I also found a really nice stainless steel container from an 'esspresso machine. It has a lid that bolts down, 3 holes which 2 need to be sealed and the 3rd has stainless tubing for gassing.

In my brainpan I can see chips evolving nicely. I'm also thinking of trying a few keyboard mylars to see how they pyrolyze.

B.S.
...2AM ramblings are usually the best thoughts visualized...

ttutone1 said:

What kind of a vessal do you guys use for a stock pot? What have you found to work the best?
I just want some opinions.
So far I have only used Hcl, Sulfuric Acid, hydrogen peroxide, Clorox, SMB and Oxalic acid. (Not all at once of course )
Would a 5 gal plastic bucket work?

Click to expand...

I'm of the opinion that many, here, don't have a clear understanding of the purpose of a stock pot.

For starters, a stock pot is not where you discard all solutions. Only solutions that may contain traces of values go to the stock pot. Otherwise you keep recycling unwanted materials, which serves no good purpose. If this isn't clear, you should go back to Hoke's book and read until it is.

There are two thoughts on the use of a stock pot. One is to recover ONLY values----so copper would be the metal of choice for cementing traces.

The other is to recover even copper, so if the waste material is later recovered via smelting, the copper becomes a scavenger, helping collect the small traces of values. If that is one's objective (as it was for me), you'd use scrap steel, but you'd send solutions to the stock pot only if they tested positive for values. All other solutions would be sent to your copper recovery bucket, which, in my case, was a five gallon plastic bucket.

My stock pot was nothing more than a five quart ice cream bucket. There was method to my madness, as when the bucket had outlived its useful life, the interior would be well coated with values. The bucket was then incinerated, for full recovery.

I kept my solutions at a conservative level by recovering values from concentrated solutions. In spite of the fact that I precipitated daily, the five quart bucket was always adequate, as I kept it well supplied with scrap steel. The more surface area you present to the solution, the faster will be the recovery. I dumped my stock pot daily as a result.

I just commented this evening on the holding of spent solutions. It's not a good idea to allow them to accumulate, as one wakes up one fine day to find one's self hip deep in solutions of unknown quality. Form the habit of testing and dealing with solutions as quickly as they accumulate to avoid that problem. It's good practice, and helps keep vapors in the lab at a lower level.

Harold

Good post as always Harold!

Personally I have two stock pots, more based on the chemistry than the metals. My first one I used for gold after precipitating. I never test the left over solution afterwards unless I see a trace of color or the solution is loaded with base metals. Anyhow all solutions goes to the stock pot and any gold in suspension have time to settle. Then I also add my washing liquids. This means I don't have to wait for fine gold to settle and dropping and washing can be done in a short time.
The other stock pot is for PGM bearing solution. I haven't used this one for so long time so I can't tell if it's working good.

Both stock pots are based on copper for cementing values.

I have harvested my gold stock pot once, recovered 1g of gold after recovered 30-40 grams out of small lots. It seems to work all right.

... oh, the container? Well for me a one liter glass jar works for me with my small volumes.

Göran

Thank you everyone for your input.
I believe I will go with a couple of one gallon plastic ice cream buckets. One for copper and one for steel.