Hi-Tech PMR (Stone Removal)

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Romantic
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Hi-Tech PMR (Stone Removal)

Post by Romantic » March 10th, 2014, 4:14 pm

I have a 2-part question. I am considering Hi-Tech PMR for a stone removal refiner. I have been using another refiner and I am not sure I have been getting a fair deal. I cut away all the gold I can from around the section with the stones and only send the stone sections in. My last stone removal lot was...

224.1g 10K
174.4g 14K
I ended up with 5.613oz of pure from this lot.

The one before that was...
192.6g 10K
183.9g 14K
I ended up with 5.512oz of pure from this lot.

Does these numbers sound about right?

Any body have good or bad comments on Hi-Tech PMR for Stone Removal?

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Palladium
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Re: Hi-Tech PMR (Stone Removal)

Post by Palladium » March 10th, 2014, 5:20 pm

Figuring stone removal is tricky. So many variables come into play that an accurate accounting is not really possible, but you can start to build an average from your lot numbers and then it's possible to spot any LARGE variations in the yields. The largest place for error is wither or not your refiner is processing the lot to completion for stone removal or are they just processing it enough for the stones to fall out. Digestion time is important and can lead to yield losses from poor processing techniques. The larger the lots the more you will notice the yield variations.
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Lou
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Re: Hi-Tech PMR (Stone Removal)

Post by Lou » March 10th, 2014, 5:40 pm

+1 Palladium.
Like chemistry? Try http://sciencemadness.org/talk

All that glitters is not gold. Occasionally it's rhodium :)

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Re: Hi-Tech PMR (Stone Removal)

Post by nickvc » March 10th, 2014, 7:11 pm

There's problems with stone removal in that the customer submits a known amount of scrap which is assumed to be plum, which it isn't, they allow nothing for the weight of the stones or the dead skin, grease, soap, hand cream etc, plating if it's white metal, do you want me to keep going, platinum heads, palladium alloyed white gold.....
Be real and accept that you dont know everything when it comes to metals!

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Re: Hi-Tech PMR (Stone Removal)

Post by necromancer » March 10th, 2014, 7:38 pm

you can also send 50% to PMR & the other 50% to the other refiner.

total weights will be a bit different because of the stones but you get the idea.

have you thought about manual removal of the stones before sending them out ?
i dont see how cutting around the stones can be much more work then removing them completely.

might be a good job for a family member if you are to busy. will assume its all types of stones...
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4metals
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Re: Hi-Tech PMR (Stone Removal)

Post by 4metals » March 11th, 2014, 1:38 am

What were the weights of stones returned from each type of material? Did you calculate the karat of the metal after subtracting the weight of the stones?

Most settings are soldered on to the piece. Solder is often a lesser karat than the piece because it will melt before the piece gets hot enough to melt, it actually makes sense. Anyway by trimming down the gold from the shanks to leave just settings you are exaggerating the effect of the solder. You are also making the lot marginally profitable for the refiner. If you only got back 5 ounces the rate for a lot that size is likely 98% so the charges were $120 - $130 in that range. When you cut the shanks there is little room for a refiner to make money so don't expect him to be paying you for any platinum which is almost always remaining with the insolubles.

Please give us all of the information from the return and we can calculate what you actually got back and what it cost you. You may have gotten a fair shake and you can't tell.
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Romantic
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Re: Hi-Tech PMR (Stone Removal)

Post by Romantic » March 11th, 2014, 9:04 am

nickvc wrote:There's problems with stone removal in that the customer submits a known amount of scrap which is assumed to be plum, which it isn't, they allow nothing for the weight of the stones or the dead skin, grease, soap, hand cream etc, plating if it's white metal, do you want me to keep going, platinum heads, palladium alloyed white gold.....
Be real and accept that you dont know everything when it comes to metals!
Actually, I am fully aware of the problems you mentioned AND I never claimed that I knew "anything" much less "everything". I simply asked "Does these numbers sound about right?". Just looking to get some kind of "average range" that others get from a stone removal lot.

nickvc
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Re: Hi-Tech PMR (Stone Removal)

Post by nickvc » March 11th, 2014, 9:39 am

Sorry if I sounded harsh but the refiner isn't always wrong, many times yes but not always.
Whenever I do stone removal I put all the pieces through an ultrasonic cleaner in a sieve and let them soak in there for a good 20 minutes then rinse off and dry and weigh, the settings really can be filthy and with the price of metal a few grams can be more than the charge to do the job. Another way to see how accurate the return from your stone removal batches are is to compare them to your normal losses on your main stream scraps, here in the UK assays on hallmarked goods have to be plum but I believe there is considerable leeway in the US around 1/2 karat I think and I bet that most material will be exactly that much under assay. As 4metals mentioned have you dicounted the weight of the stones from your starting weight and then calculated the fine content based on 9.5 k and 13.5 k.

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4metals
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Re: Hi-Tech PMR (Stone Removal)

Post by 4metals » March 11th, 2014, 8:35 pm

I believe what Nick meant when he said you don't know everything when it comes to metals is that nobody does. Not Romantic specifically.

i happen to know a fair amount about metals, but if I was not there to witness a melt and take a sample, my knowledge would be limited. I could analyze the sample for all base metals ( a cost which would not be wise to incur save for an XRF result) and that could tell me something about the lot as a whole but I would not know if a lower karat solder was used. Nick used karats of 13.5 and 9.5 in his example but the karating laws allow the overall karat to be as low as 1/2 a karat low and that refers to the entire piece. When you cut off the shanks and only send in the part which likely has the solder on it you actually exaggerate the low karat solder effect and the number can dip below the 1/2 karat.

Again knowing the stone weights will fill in some blanks.
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Re: Hi-Tech PMR (Stone Removal)

Post by Dan Dement » March 12th, 2014, 9:32 pm

I am certainly no metal expert but another factor can be what stones are coming back. If most of the jewelry is CZ, you got aa 50% more weight factor with C.Z.'s being heavier. We do our stone removal and yyou probally are getting your CZ's back frosted for easy separation. LArger stones can throw your factor off. Simple snippiing off the shanks and sending all the small stones iwith the metal can save you lots of labor and perhaps raise your rate of return. I don''t use HiTech but hear they are good people. If you want to bring a small load, I will happily set you down at a bench, let you break out your stones, let you induction melt the batch, and then run both a S.G. and multi XRF readings. With this method, I have been able to keep my payouts within a $50 window at the $15,000 area.

Sometimes I get a little more and sometimes it is a little less but I know the number before I cash out. I have done this hundreds of time and nice to get a check in 15 minutes or so. Everyone thinks the refiner is nailing them and being lesss than honest. Best method is spend the time and get it ready to sell then Get it analyzed! Know what you have before you sell it and then see you pays you what. Lots of ways to get the lowest possible readings. Good XRF's are not cheap! Having to spend the time to build good Standards to check the machines does not happen overnight. Many things to consider. How much gold or money are you cashing out at a time? If it isunder a couple of thousand, it might not worth it to you to do thru all the hassle. Larger amounts might make it worth while. For about $2,000 you can buy a good S.G. scale that will get you within .015%.

Good Luck,
Dan

Romantic
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Re: Hi-Tech PMR (Stone Removal)

Post by Romantic » March 21st, 2014, 6:22 pm

You signature refers to a Gold Refining Handbook Vol 1 & Vol 2.
Is Vol 2 an updated version of Vol 1 or is it a continuation of Vol 1?

Thanks
Palladium wrote:Figuring stone removal is tricky. So many variables come into play that an accurate accounting is not really possible, but you can start to build an average from your lot numbers and then it's possible to spot any LARGE variations in the yields. The largest place for error is wither or not your refiner is processing the lot to completion for stone removal or are they just processing it enough for the stones to fall out. Digestion time is important and can lead to yield losses from poor processing techniques. The larger the lots the more you will notice the yield variations.

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Palladium
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Re: Hi-Tech PMR (Stone Removal)

Post by Palladium » March 21st, 2014, 6:24 pm

A little of both actually.
The difference between stupidity and genius is that genius has its limits. Albert Einstein
1. Refining Precious Metal Wastes C.M. Hoke http://tinyurl.com/mfnyhs
(REV) (Free Download)
2. Get the (FREE) Gold Refining Forum Handbook VOL 1 here >> http://tinyurl.com/nyutnp
3. Get the (FREE) Gold Refining Forum Handbook VOL 2 (Final) here >> http://tinyurl.com/y9w5y73
4. Silver cell setup video here (FREE) >> https://tinyurl.com/jhzadse
ALL FREE-----ALL THE TIME

guldspecialisten
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Re: Hi-Tech PMR (Stone Removal)

Post by guldspecialisten » April 18th, 2014, 3:05 pm

Hello, this is my first post as I have just been reading the forum for a long time.

I have been doing my own stone removal for some time and it works pretty well. I think the returns "romatic" is getting do not sound unrealistic taking the weight of the stones into consideration and that the carat can be more than 1/2 carat below actual carat. He is getting approx. 1/2 troy ounce less than calculated, not considering weight of stones etc.

Another important factor is how much or little gold he leaves around the stone and the size/weight of the stones.

I remove all the big stones manually and only the small stones are removed by digesting in AR. The process takes a lot of time especially because some of the material has a high silver content and does not dissolve so easily and some parts will take forever to dissolve.

The parts that did not completely dissolve (some almost do not dissolve) I always save for the next lot. But before I treat them with AR again I remove the silver chloride from the surface of these parts.

Some would probably use ammonia to dissolve the silver, which means they would have to use HCl to recover the silver as silver chloride. I have had great experience covering the parts with 10-15% Sulphuric acid and adding a few pieces of iron. I just leave the solution and just stir once in a while and within 2-3 hours all the silver chloride has been converted to metallic silver which has detached from the surface of the gold parts.

I wash the metallic silver with the gold parts, stones etc. a few times and then I can digest the metallic silver adding diluted nitric acid 1:1. Now only the undigested gold parts, stones, rhodium and some gold powder (maybe other PGMs) is left in the bottom.

I decant the silver nitrate solution, wash the residue and I can now easily remove the undigested gold parts for the next AR lot.

The stones with the gold powder, rhodium and other possible PGM's I digest in AR again. Then only the stones are left with some rhodium.

I recover the gold from the AR using SMB and the rest is sent to the stock pot for later treatment.

I would be glad if someone would give me any feedback on my stone removal process and maybe help with some improvements.

Thanks in advance :)

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Re: Hi-Tech PMR (Stone Removal)

Post by 4metals » April 19th, 2014, 9:20 pm

Your process sounds fine, you have the added luxury of owning all of the gold that comes out of your process so you do not have to get every bit possible for the customer from every lot in a timely manner. Because of the fact that you can wait for full recovery, the sulfuric iron treatment to reduce silver chlorides to metallic silver is a good choice if it fits your processing schedule.

Refiners who process material and pay on out-turn need to process material quickly and get all of the gold out in an efficient manner. That is why they use either ammonia or sodium thiosulfate. I do not like ammonia because of the fumes, although it does a decent job. I prefer to tumble the insolubles in a solution of sodium thiosulfate which polishes the gold to a nice yellow luster, and dissolves the silver chloride. The silver is recovered from the thiosulfate by passing it through steel wool canisters.

You are wise to do a preliminary digestion in nitric as 9 and 10 karat scrap will digest a good portion of the base metals and silver before the aqua regia and the silver is easily recovered by cementing with copper.

If fumes are an issue you might consider using ferrous sulfate to drop the gold, much easier on the nose.
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guldspecialisten
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Re: Hi-Tech PMR (Stone Removal)

Post by guldspecialisten » April 22nd, 2014, 5:12 am

Thanks for your comments 4Metals.
You´re right that owning all the gold gives an added luxury as I do not need to get all the gold out urgently. Its also Interesting to learn how refiners process this type of material.
The gold is mostly 14K + , but some parts can be 8 or 9K and it would certainly speed things up with a preliminary digestion in nitric. Thank you for that good advise :)

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