Newbie's garage - a cautionary tale

hi, I’m a newbie to this group. But I do have kind of a PM challenge on my hands. Kind of a cautionary tale, too. And at the outset, I’m glad to have found the “Chemicals” section on this site; I’m applying the advice there immediately. For this info. my family and neighbors are (unknowingly) grateful, as well.

In general, I’m looking for ways of dealing w/ the 500 lbs. or so of crushed ore in my garage, hopefully in ways that are more efficient than what I’ve already tried. I should mention, too, that living as I do in a large urban area, that it’s hard to do ANYTHING unnoticed. Also, FTB, moving to another more congenial location is unlikely.

Background: A year or two ago I made myself a ball mill that’s been cranking out several hundred pounds of fine mesh (<100) of crushed electronics boards. (Unfortunately I’ve had to stop it for the time being. Just too much of the nasty black stuff collecting in the garage). The daunting challenge now is to try to attempt PM recovery. I’ve already made a few dangerous mistakes—pouring acid directly onto fine mesh powder is just one example of something I’ll do more cautiously in the future. Even my high-school age kid told me, “dad, be sure to WAFT, not SNIFF”, as I used to stand over buckets of fizzing glop. And I should thank Lou B, for a recent private email, stressing that probably CN extraction is probably beyond a reasonable threshold of common-sense safety for me, working as I do in a residential neighborhood.

Attempts so far:
1st batch (goof #1-abandoned) pouring a quart or two of HNO3 50% directly onto mesh powder outside in a 5-gal bucket. Copious billows of acrid red smoke. Result: a frothing glopping mass. Values unrecoverable, because of oxides of Pb and Sn started forming in the bucket almost immediately, thus contaminating the ore.

2nd attempt, new batch (in process): starting w/ HCl to remove Sn, Al, and Zn, at the very least. More manageable fumes. I’ve rinsed the batch w/ rainwater and let it dry. I suppose that now I might treat it w/ HNO3, and later AR. Still, lots of acids just for a single 5-gal (50lb) batch

3rd attempt (in process): taking ore already treated w/ HCl (w/ Sn, Al, and Zn removed, in theory), and attempting poor-man’s Parkes’ Process: melting 15 lbs of tire weights, and dunking the ore in a bath, a few pounds at a time. Kind of acrid smelling, no doubt from the remaining trace HCl at 600F. Also, in Parkes’, I’m looking for tips for separating the Zn-PM alloy from the molten Pb; there must be a trick to stirring it in and then floating it off. One problem is that this method would work much better, say, w/ 10 times the molten Pb than I can reasonably manage.

4th attempt (no way): CN. Lou B has already advised me out of this one.

Frankly, between methods 2 and 3, maybe I can get sumpn’ going, but it’s a long haul.

Look forward to following posts, and (hopefully) posting soon,
SamW

I think at this point (after ballmilling everything) you will have to incinerate.

But I would not want to be around to smell, breath, that.

To do it right, you would at least need some type of reburner....and possibly a scubber of some sort.

Also, have you thought of tabling? To separate a metalic portion.
Randy

tabling? is that the same as classifying? I made a shaker to sift out 30 mesh, 50, and 100s. Unfortunately my high values are sitting in the bottom of my first ruined batch.

Well, tabling is a way to classify by density.
Randy

hi there
my self am a newby to refining pm's but not to collecting karat gold and plated stuff . just from reading what you have posted so far im my opinion you are shooting into the dark and should stop right away until you know more about what is going on and perhaps do small test batches . such as one ounce test batches to see what pm's are present etc . i am not saying you dont know what you are doin but i would be wondering if i seen a red cloud over my neibours house . as for my advice read more and do way smaller batches to fine tune your skills and study the msds of everything you use as well as perhaps do a little bit of safty practise such as excape routes, chemical hazards and recovery,containment of spills and neutralization etc. take an inventory of the safty gear you have , do you need some or do you have everything. thats just a few things i can think of at this time and i hope this helps you as im sure you will get more comments etc from others more knowledgeable than i .
thanks
ian

ps: do more research as well !

I'm glad you joined up here so quickly Sam. There are many very knowledgeable people on this board.


More and more I have been thinking of your problem from a cupola perspective...I feel like something could be done with it. Also, since they run at such a high heat, with both oxidizing and reducing zones, vaporisation of the nasties to a safe(r) form would be a benefit. An electrically expensive way, but nonetheless commercial method is to use copper as a collector, then do electrolysis. Your anode anode slimes would contain the values, and your refined copper would be reused in the cupola. It is a technically challenging project and really is only suitable if you a.) have a shop where you can get high amperage supply, b.) know thy electrolysis well, c.) have a steady supply of scrap and money, d.) build and know how to operate a cupola. There are a lot of things to surmount, and unless you have tons of the stuff, the profit might be lost in the tooling up.

Mainly though, I think you are trying to reclaim too many of the values. I would settle for the gold and not pursue the PGMs and silver present in the electronics scrap.

Sam,

Small scale testing is the best route until you are sure of a sound process.

You may be able to use HCl-Cl to leach the batches once the base metals are removed with HCl.

Something like a large bucket or barrel with an ultra fine mesh in place of a bottom to stop the flow of the ore yet allow the flow of the liquids thru the heap. This run off would be slow by design. The run off is collected and further filtered and the PMs recovered from it. You may start with a clean water leach or two to remove any remaining base metals that were dissolved by the HCl, but not removed by the rain water rinse. This would also serve to get the liquid phase evenly distributed thru the heap.

The reaction bucket or barrel would only be filled halfway up with ore and the remaining volume would be filled with fresh HCl. When the HCl finally made it to the bottom and began dripping is when you would begin the introduction of the clorox. The heap would be like a thick porridge.

The real trick would be the introduction of the clorox into the heap. I could see several PVC, or better yet Teflon, tubes pushed down into the heap which contained the ore and HCl. Introduce your bleach in small doses into the tubing which extends to the bottom of the heap and let the chlorine produced seep into the heap.

Alternately you could leave the bottom intact and place several PVC well points into the reaction barrel and introduce the clorox under pressure into the well points. The clorox would be forced into the heap and react with the HCl producing chlorine which would extract your PMs. The added feature of the well points is that you could remove the liquids once pregnant thru the well points also. Clogging may be an issue.

Just some quick brain storms I've come up with.

I also have around a thousand pounds of boards that I need to process one day, but I don't have a ball mill yet.

Let us know what you come up with and welcome to the forum.

Steve

Halide leaching: In the summer months it works here. In the meantime, I’ll try an experimental batch, adding HCl and bleach to less-than-a-bucket-load. Maybe I can find a heating pad.

In the past I tried a bucket of smashed catalytic converters, soaked in a solution of brine, HCl, and bleach. And as I remember, the fumes (outside) weren’t bad; at least they weren’t clouds. I poured off the liquor, rinsed the ore, and reduced to slime w/ NaOH. Dried. Fired. Ended up w/ some kind of nugget. (Little did I suspect how different my first experience w/ nitric would be.)

One or more of the following might be a niftier way to reduce the values from the halide liquor than NaOH, and producing less volume in the way of slime. Elsewhere on this site I saw info posted about a sodium complex that reduces pure metal out of liquor, if only it weren’t so expensive.

1. plate out w/ Zn or Cu, or a mixture (here being careful to make sure the pH isn’t too low, or I’ll make another storm cloud of Zn in HCl)
2. invest in some of those ‘Premion’ metalics sold by Alpha-Aeser, and others
3. invest in ‘catalytic fibers’, also by Alpha-Aeser and others
4. other?

what do you mean ruined/

just process the mess. with what ever method you want to.

the values will still go into solution. just a few other items to get rid of but the gold etc is still there. or just ship me all of it and i will dispose of that mess for you at a reasonable cost.