kadriver said:
Harold_V said:
For exceptions, such as when a customer submitted a platinum object, if they could reuse the platinum, it would be pickled until it fell apart.
Can you describe the process you used for "pickling" the platinum object?
Simple. I prolonged boil in a covered vessel in which one has AR. Platinum is very slow to dissolve, so the solder is attacked quickly by comparison.
Remelting used platinum isn't a good idea, as silver combined with platinum tends to yield a brittle alloy. The solder used for platinum contains at least traces of silver, so it's a good idea to rid the object of all solder.
You're going to be surprised at how many pieces make up a platinum article. Some items, which you will have wrongly concluded are a single piece, may well be made up of several smaller pieces, which I suspect are die struck instead of cast.
Harold_V said:
In regards to silver, most of my customers weren't all that concerned (unless they were silversmiths), but I had a policy of returning silver, based on percentage.
kadriver said:
Harold, do you remember what percentage was used? I am going to process the silver via silver chloride, lye and sugar, then offer my customer his silver back.
I think it was 7% of the total weight of gold recovered. It's been more than 20 years now, so my memory may not be correct.
There are probably about 2.5 ounces in these last two batches. This will also provide some accounting with respect to the amount of gold recovered from both batches.
We are using 20% as the refining fee, so I'll just keep 20% of the silver then offer the customer the rest.
I'm assuming your 20% fee is for silver, not gold. If you are charging and getting 20% for gold, you're most likely going to lose that customer in due time, as others present a far more attractive offer. I charged 10%, and dropped my fee to 8% if the yield was greater than five ounces. That may appear to be unreasonable to those who keep reading how gold is refined for a few cents per ounce, but keep in mind, there were NO other charges, which is conveniently overlooked when low refining fees are discussed. By the time a major refiner is finished with the charges that accompany a shipment, the 10% fee is actually very reasonable. My fee for refining silver was 20%, eventually raised from 15%, which was a losing proposition for me. Silver is rather labor intensive unless processed in large volumes.
The silver I returned to my customers was by way of crystals from the cell. I would strongly recommend you NOT return recovered silver, regardless of the method of recovery, unless it has been parted. Two good reasons why that is. One of them is that silver is the carrier of the platinum group, so you may be giving away considerably more value than intended. The second one is because the silver won't be pure, it may or may not be useful to the individual, and if used, could present problems (brittle silver, for example), which will reflect directly on you, as if you are not competent to provide pure metal. Make damned sure you don't dispense anything that is contaminated. Ever! If a customer has problems because of you, he will be lost, as well as speak poorly of you to others. Avoid that like the plague.
Harold_V said:
What makes the most sense is that you don't spend time chasing traces of values, yet when the time comes to recover, you're rewarded very handsomely.
Harold
kadriver said:
I was actually evaporating a solution with trace amounts to get at the PGMs and it dawned on me that this was a waste of energy and time.
I got out a clean 5 gallon bucket made of HDPE and dumped the solution into the bucket then added a tablespoon of iron filings.
From now on I am going for the "stock pot" retirement plan and plan to add all my gold refining wastes to catch any PMs.
I just wonder how much I have thrown away by committing it straight to waste treatment. Putting it all in the stock pot makes so much more sense!
I was alway vague about the function of the stock pot - now that I am seeing more and more trace amounts of PGMs by refining wastes that contain them, the function of the stock pot has become very clear.
kadriver
Many will most likely not agree with me, but precious few, so far, appear to grasp the importance or function of the stock pot. That, of course, depends on how one would intend to recover the values. If it is intended to be by furnace, using copper is not a good idea, as one must create a collector. I intentionally added not only copper (from the stock pot), but filters from gold refining, all incinerated for storage. Because I used tap water for all my processing, I created traces of silver chloride. That was actually part of my plan, as I knew a collector would be required, and it proved to be an excellent source, based on the results I achieved by furnace. It was also far more convenient to use tap water than be troubled by constantly distilling, or being trapped in the world of having to purchase distilled water. The only time I used distilled water was in the operation of my silver cell. YMMV.
By the way, in regards to using "a hand full of iron filings", while they work, I'd highly recommend to you that you use pieces of iron. Rebar, bits of channel or angle iron, or even pieces of scrap sheet or plate steel. That way, when there's enough accumulation in the bucket you use as a stock pot, the pieces can be removed and the values recovered. By allowing the solution to settle fully, you can then decant by siphoning, leaving only a small amount to be filtered, where the values are collected. No need to even clean the pieces, as any values that are attached will be returned to the stock pot, where they will be liberated as the material is dissolved in time. Just keep a generous amount of scrap steel (iron) in the stock pot at all times.
Tip----anything that is removed from filings in the way of iron is sent to the stock pot. That way traces of values that are removed with the steel are not lost. I gave them a second or even third rubbing in a mortar, returning any non-magnetic "dirt" to the filings. That way the customer isn't cheated, but traces are also not lost. That's one of the reasons that using steel makes more sense than using copper, although steel introduced to a copper stock pot will be consumed, producing more copper, which, in turn, will recover greater values. You just can't separate the fine bits of copper easily if the stock pot is cleaned out.
Harold
