joem
Well-known member
could you not just use an electric drill or dremel with a wire brush wheel to get the layer of gold off, and a vacuum to collect. This would minimize the amount of metal to deal with when processing.
my thought
my thought
Acid Peroxide on Teflon Fiberglass
- Thread starter FrugalEE
- Start date
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I am really enjoying this thread. It gets down to the nitty gritty of what refining is all about - setting up goals, experimenting, and then going with the best bet. I would think the goals should be such things as simplicity, speed, inexpensive set-up, small amount of waste, low chemical cost, and, most important, efficiency - you want to get essentially 100% of the gold. Also, there are questions such as what amount of fumes your setup will tolerate.
Sorry, I didn't notice that both sides had traces. Back to square one.
From your most recent figures, there are 5472 sq.in. of plated area on the 2-sided 125 sheets (100@12x21 and 25@12x12 - your figure of 24 sq.in. on one side of the 12x21 sheet comes out to about a 9.52% plated area). From all this, there are 86.5g Au, 558g Cu, and 80g Ni. The total of all three is 724.5g and the total of the Cu and Ni is 638g.
Theoretically, it would take 2.66 liters of 70% nitric to dissolve all of the Cu + Ni and it would take 3.02 liters of 4:1 AR to dissolve everything.
I still don't think that anyone knows the best way to run this stuff. We have come up with quite a few options. They would probably all work but some would work better than others.
The more I think about this, the more I think that the material is best left in sheet form and not shredded. I know that this will take more handling but, if you use nitric or HCl/H2O2 to dissolve the Cu/Ni, the loose foils would be easier to remove from the sheets than from the shredded material. If you used AR or HCl/bleach to dissolve everything, the sheets would be easier to rinse than shredded material.
It sounds like the HCl/H2O2 is sort of working for you in what you've done so far. One good thing about this solution is that it's cheap and, since it's only dissolving the Ni and Cu, you can use quite a bit of it.
How to run more than 1 sheet at a time - thinking out loud department. What if you had a 5 gallon bucket and a 3 gallon bucket (with maybe a dozen 1/2" holes drilled around the sides and 3 or 4 on the bottom), that fit inside of the 5 gal bucket? The sheets could be cut in half (into 6" x 21" pieces), a few plastic paper clips put every 3", or so, on the top, bottom, and end edges of each sheet to act as sort-of spacers, and then the sheets could be curved around the inside of the inner bucket - it shouldn't make much difference if they overlap on the ends. You could probably put quite a few sheets in there at one time. The inner bucket should have a plastic handle so it wouldn't get eaten by the acid. You could normally keep a lid on it and then, occasionally, lift the inner bucket up (slowly!) to drain and then put it back it. As you brought the bucket in and out several times, you would surely get solution flow between each sheet and agitation always improves the reaction rate. The only thing making the sheets stick together is surface tension. This would be broken easily, I would think, by the solution flow. I would imagine the plastic paper clips are PE (same as the buckets) and wouldn't be affected by the acid. It would probably take about 3 gal of acid to cover the sheets.
I would suggest trying this on a very small scale using smaller strips of material. Just use a couple of small plastic containers. I would first try HCl/H2O2. If that works, you may be home free.
This could be done with nitric or HCl/H2O2. If using nitric, I would set the outer bucket in a plastic tray in case of foamovers. I would think that nitric would be much faster.
All of this assumes that the acid will penetrate through the gold and will dissolve 100% of the Ni/Cu. If it doesn't, you will probably have to consider dissolving all of the metal with AR or HCl/bleach.
I would bet that lazersteve has some suggestions on how to best use the HCl/H2O2 in this application.
OR, maybe you could just use two gallons of AR in the outer bucket and cut the sheets in thirds (4"), the long way, using the same 2-bucket/paper clip system as above. I would think this would be the fastest way, by far. Also, you wouldn't have to screw with collecting the foils. As Oz said, use only enough nitric as necessary and you won't have to evaporate.
Sorry, I didn't notice that both sides had traces. Back to square one.
From your most recent figures, there are 5472 sq.in. of plated area on the 2-sided 125 sheets (100@12x21 and 25@12x12 - your figure of 24 sq.in. on one side of the 12x21 sheet comes out to about a 9.52% plated area). From all this, there are 86.5g Au, 558g Cu, and 80g Ni. The total of all three is 724.5g and the total of the Cu and Ni is 638g.
Theoretically, it would take 2.66 liters of 70% nitric to dissolve all of the Cu + Ni and it would take 3.02 liters of 4:1 AR to dissolve everything.
I still don't think that anyone knows the best way to run this stuff. We have come up with quite a few options. They would probably all work but some would work better than others.
The more I think about this, the more I think that the material is best left in sheet form and not shredded. I know that this will take more handling but, if you use nitric or HCl/H2O2 to dissolve the Cu/Ni, the loose foils would be easier to remove from the sheets than from the shredded material. If you used AR or HCl/bleach to dissolve everything, the sheets would be easier to rinse than shredded material.
It sounds like the HCl/H2O2 is sort of working for you in what you've done so far. One good thing about this solution is that it's cheap and, since it's only dissolving the Ni and Cu, you can use quite a bit of it.
How to run more than 1 sheet at a time - thinking out loud department. What if you had a 5 gallon bucket and a 3 gallon bucket (with maybe a dozen 1/2" holes drilled around the sides and 3 or 4 on the bottom), that fit inside of the 5 gal bucket? The sheets could be cut in half (into 6" x 21" pieces), a few plastic paper clips put every 3", or so, on the top, bottom, and end edges of each sheet to act as sort-of spacers, and then the sheets could be curved around the inside of the inner bucket - it shouldn't make much difference if they overlap on the ends. You could probably put quite a few sheets in there at one time. The inner bucket should have a plastic handle so it wouldn't get eaten by the acid. You could normally keep a lid on it and then, occasionally, lift the inner bucket up (slowly!) to drain and then put it back it. As you brought the bucket in and out several times, you would surely get solution flow between each sheet and agitation always improves the reaction rate. The only thing making the sheets stick together is surface tension. This would be broken easily, I would think, by the solution flow. I would imagine the plastic paper clips are PE (same as the buckets) and wouldn't be affected by the acid. It would probably take about 3 gal of acid to cover the sheets.
I would suggest trying this on a very small scale using smaller strips of material. Just use a couple of small plastic containers. I would first try HCl/H2O2. If that works, you may be home free.
This could be done with nitric or HCl/H2O2. If using nitric, I would set the outer bucket in a plastic tray in case of foamovers. I would think that nitric would be much faster.
All of this assumes that the acid will penetrate through the gold and will dissolve 100% of the Ni/Cu. If it doesn't, you will probably have to consider dissolving all of the metal with AR or HCl/bleach.
I would bet that lazersteve has some suggestions on how to best use the HCl/H2O2 in this application.
OR, maybe you could just use two gallons of AR in the outer bucket and cut the sheets in thirds (4"), the long way, using the same 2-bucket/paper clip system as above. I would think this would be the fastest way, by far. Also, you wouldn't have to screw with collecting the foils. As Oz said, use only enough nitric as necessary and you won't have to evaporate.
I originally thought of something similar but rejected it - using a small orbital sander with a dust bag on it. However, I have been involved with several of those catch-the-dust things and there usually are losses.joem said:
Joem,
I'm in final stage of cleaning up and I can't believe how hard it is to get all the tiny flakes coralled. I've decided that I better stop pushing around on loose pads with a stick and just use the squirt bottle to keep pieces as large as possible.
I think your abrasive technique would loose a lot of gold that you could never get out of your vac or brush. The goal is to get scattered gold(thin runs) that may be contaminated back into a large pure piece. There may be a place for abrasive techniques, but I would do it in a closed tumbler jar set up like a rock hound uses. I expect that would make some pretty fine dust that would almost have to be dissolved chemically or in an oven to avoid a torch blowing it all over.
Wire brushing my boards off sounds like an extreme amount of work and right now the chemistry sounds like a whole lot more fun.
It's time to get some drying action on my first gold pile and then respond to GSPs fine post.
FrugalEE
I'm in final stage of cleaning up and I can't believe how hard it is to get all the tiny flakes coralled. I've decided that I better stop pushing around on loose pads with a stick and just use the squirt bottle to keep pieces as large as possible.
I think your abrasive technique would loose a lot of gold that you could never get out of your vac or brush. The goal is to get scattered gold(thin runs) that may be contaminated back into a large pure piece. There may be a place for abrasive techniques, but I would do it in a closed tumbler jar set up like a rock hound uses. I expect that would make some pretty fine dust that would almost have to be dissolved chemically or in an oven to avoid a torch blowing it all over.
Wire brushing my boards off sounds like an extreme amount of work and right now the chemistry sounds like a whole lot more fun.
It's time to get some drying action on my first gold pile and then respond to GSPs fine post.
FrugalEE
GSP,
I certainly am enjoying this project as well and am glad it has peaked your interest. It's got my problem solving juices going again and I've given up TV and find it hard to shut my mind off when it's time to sleep.
As to what kind of fumes I can tolerate lets just say I have access to a pretty isolated country place.
You mentioned bending around in a circle. These thin boards probably handle best that way as it gives them ridgidity. Your description needs further study on my part, but I'm visualizing concentric circles.
The plastic paper clips sounds like an excellant idea, but they like all other spacers are going to mask out something. These boards have a .050 inch wide border all the way around them. This is less of a problem if the boards etch pretty fast as the clips can be moved or just accept the loss. This fixturing can all be worked out using only nice safe water.
I was also thinking of rigging up a rectangular card cage arrangement and that would probably work well in a plastic storage bin for the acid. The boards would have to be cut into something like 6 X 6 pieces to get any kind of ridgidity.
I noticed today that it is convienent to hang up individual sheets to dry as there are lots of bolt & contact holes to use.
My foils are nearly dry.
I too was looking forward to Lazer Steve stopping by. I plan to order his silver video and some crucibles.
FrugalEE
I certainly am enjoying this project as well and am glad it has peaked your interest. It's got my problem solving juices going again and I've given up TV and find it hard to shut my mind off when it's time to sleep.
As to what kind of fumes I can tolerate lets just say I have access to a pretty isolated country place.
You mentioned bending around in a circle. These thin boards probably handle best that way as it gives them ridgidity. Your description needs further study on my part, but I'm visualizing concentric circles.
The plastic paper clips sounds like an excellant idea, but they like all other spacers are going to mask out something. These boards have a .050 inch wide border all the way around them. This is less of a problem if the boards etch pretty fast as the clips can be moved or just accept the loss. This fixturing can all be worked out using only nice safe water.
I was also thinking of rigging up a rectangular card cage arrangement and that would probably work well in a plastic storage bin for the acid. The boards would have to be cut into something like 6 X 6 pieces to get any kind of ridgidity.
I noticed today that it is convienent to hang up individual sheets to dry as there are lots of bolt & contact holes to use.
My foils are nearly dry.
I too was looking forward to Lazer Steve stopping by. I plan to order his silver video and some crucibles.
FrugalEE
qst42know
Well-known member
If these boards bend easily could you make two parallel cuts a half inch apart and an inch or so long and bend the tab to keep them separated?
QST, Thanks. Slotting and bending should work with this stuff. This project just keeps getting better and better.
I dried my foils in our kitchen oven at warm setting which was enough to singe the edge of the filter paper.
RESULTS: I'm excited to announce that the reading I got on the collected foils is that the gold foils weigh 0.85 grams. (The scale toggles between 0.8 and 0.9.) The predicted amount based on minimum gold thickness of 50 microns was 0.76 grams.
Sources of error:
1. The scale is a $12 digital one I got at Harbor Freight & has only 0.1 gram resolution.
2. I'm doing some more drying to see if I got all the water
3. I used a different filter than the one containing the gold for tare
4. I'm sure there is gold left in the solution and also there are purplish black stains in the dishpan that don't want to come out easily.
5. I only washed the gold a little and didn't bother to treat with HCL so that is another possible way to come up on the high side.
Conclusions: The 50 micron min. spec was met and then some and this material is definitely worthwhile to process.
I've taken some pictures and I'll edit and try to post them later this evening.
FrugalEE
I dried my foils in our kitchen oven at warm setting which was enough to singe the edge of the filter paper.
RESULTS: I'm excited to announce that the reading I got on the collected foils is that the gold foils weigh 0.85 grams. (The scale toggles between 0.8 and 0.9.) The predicted amount based on minimum gold thickness of 50 microns was 0.76 grams.
Sources of error:
1. The scale is a $12 digital one I got at Harbor Freight & has only 0.1 gram resolution.
2. I'm doing some more drying to see if I got all the water
3. I used a different filter than the one containing the gold for tare
4. I'm sure there is gold left in the solution and also there are purplish black stains in the dishpan that don't want to come out easily.
5. I only washed the gold a little and didn't bother to treat with HCL so that is another possible way to come up on the high side.
Conclusions: The 50 micron min. spec was met and then some and this material is definitely worthwhile to process.
I've taken some pictures and I'll edit and try to post them later this evening.
FrugalEE
Barren Realms 007
In Remembrance
Make a dilute solution of AR and see if it takes the stain out.
FrugalEE,
If you can, please post some photos of the original material. Even a scanner would work.
Don't you love it?
Chris
If you can, please post some photos of the original material. Even a scanner would work.
Don't you love it?
Chris
This should document what I've done in the past few days. Putting photos on the forum looks easier than I thought it might be, but I just looked and saw they got truncated so I've got to limit the vertical dimension a bit more. I belive I read someone say 600 pixels max. I also see the first one submitted ends up at the bottom and I intended the reverse order.
This sort of closes this phase of the project and I've got to give it a rest now and get some other things done while we have nice fall weather. I'll be reading your responses until early tomorrow, but for the rest of the week I won't be able to read or respond. I'll definitely be back to the forum & will begin the next phase after that.
Many thanks for all the good responses so far,
FrugalEE
This sort of closes this phase of the project and I've got to give it a rest now and get some other things done while we have nice fall weather. I'll be reading your responses until early tomorrow, but for the rest of the week I won't be able to read or respond. I'll definitely be back to the forum & will begin the next phase after that.
Many thanks for all the good responses so far,
FrugalEE
Attachments
Update: Oz agreed to do a test with nitric acid so I sent him a board and I got a detailed report with status every 10 minutes. With 25% nitric all the foils were free in 2 hours and with 50% nitric it took an hour.(I suspect that every time you cut the strength in half the time to etch doubles.) With that results I went and bought a gallon nitric as soon as I could. Following up on GSP's post of Nov. 4, 2009 I went to Terrace Packaging in Kansas City, MO and bought a gallon for $16.50 plus tax.
Oz also warned me to avoid using any water that might have chlorine in it so I bought a gallon of distilled and the rest I'm using water from our dehumidifier. This way I don't have to worry if a batch is left in a long time about dissolving any gold.
Set up for Volume: In previous posts we have determined that about 1/2 gallon of acid would do a 100+ boards. In order to get enough volume for any kind of production I went ahead and mixed the 1/2 gallon of 67% nitric with 5 quarts of water. I put this in a 5 gallon pail. The boards to be etched are put in a 2 gallon pail which I have drilled holes similar to Steve's AP video set up. As of this writing I have etched 30 boards mostly 4 at a time. To prepare the 6 mil thick 12 X 21 inch board I fold it in half so that I have a piece 6 by 21 inches. I then cut it into 4 equal pieces. I then stack those pieces rotating each added piece 90 degrees. That gives me a pretty even stack with enough space for the acid to get to all surfaces. For the most part I don't aggitate at all, but sometimes rock the outer 5 gallon pail a bit if I'm in the area. It takes about 6 to 8 hours for a batch to completely etch. Sometimes I have a few pads still stuck on and I cut those out and run them in another small set up.
I'm sure the set up could be improved a bit more by having a smaller outer container so fluid would rise higher, but I'm getting the job done and accumulating a nice batch of gold spaghetti in a caserole dish.
Fumes: I'm running this in the garage near the door and open the door occassionally. I am not getting noticable brown NO2 fumes and it's only when I take the lid off to change the batch that the odor is real bad. In some earlier small scale work on my work bench I rusted a couple of tools.
FrugalEE
Oz also warned me to avoid using any water that might have chlorine in it so I bought a gallon of distilled and the rest I'm using water from our dehumidifier. This way I don't have to worry if a batch is left in a long time about dissolving any gold.
Set up for Volume: In previous posts we have determined that about 1/2 gallon of acid would do a 100+ boards. In order to get enough volume for any kind of production I went ahead and mixed the 1/2 gallon of 67% nitric with 5 quarts of water. I put this in a 5 gallon pail. The boards to be etched are put in a 2 gallon pail which I have drilled holes similar to Steve's AP video set up. As of this writing I have etched 30 boards mostly 4 at a time. To prepare the 6 mil thick 12 X 21 inch board I fold it in half so that I have a piece 6 by 21 inches. I then cut it into 4 equal pieces. I then stack those pieces rotating each added piece 90 degrees. That gives me a pretty even stack with enough space for the acid to get to all surfaces. For the most part I don't aggitate at all, but sometimes rock the outer 5 gallon pail a bit if I'm in the area. It takes about 6 to 8 hours for a batch to completely etch. Sometimes I have a few pads still stuck on and I cut those out and run them in another small set up.
I'm sure the set up could be improved a bit more by having a smaller outer container so fluid would rise higher, but I'm getting the job done and accumulating a nice batch of gold spaghetti in a caserole dish.
Fumes: I'm running this in the garage near the door and open the door occassionally. I am not getting noticable brown NO2 fumes and it's only when I take the lid off to change the batch that the odor is real bad. In some earlier small scale work on my work bench I rusted a couple of tools.
FrugalEE
Way to go....I agree with GSP this is what refining is all about working out a way to get your values in an economical and simple repeatable way. The maths by GSP I'm sure are right as your experiment proved so you will have around $4000 worth of gold or better still a nice button.....be aware this can become addictive 8)
FrugalEE,
Just remember that you won't know exactly how much gold you have until you refine the foils. Just weighing the foils might be misleading. Also, my prediction was based on the gold thickness you initially provided. 50 millionths (not 50 microns) has always seemed somewhat high to me but, who knows?
Just remember that you won't know exactly how much gold you have until you refine the foils. Just weighing the foils might be misleading. Also, my prediction was based on the gold thickness you initially provided. 50 millionths (not 50 microns) has always seemed somewhat high to me but, who knows?
FrugalEE said:
One micron is 40 millionths of an inch (40 microinches) = .000040".
It's probably long past time for an update. I have continued to process the 12 X 21 inch boards as stated above, mostly on weekends using the original 2 qts of nitric to 5 qts of water. On Nov 2 after processing about 90 boards time to etch was getting to about 4 days so I added another quart of concentrated nitric and that got me back to something like 24 hour etch time. I now have processed 131 boards have the equivalent of 37 to go, plus I have 6 in solution that are taking a long time to finish. A few days ago I added 2 more quarts of water thinking that the solution might be getting saturated with Cu and Ni, but I don't think that helped. I also added some heat and not sure that helped much either. I have to admit that I'm also taking incomplely etched boards, cutting out the portions with gold still hanging on and etching them separately in a stronger solution.
When the ones in solution are finished I will have dissolved about 677 grams of Cu and 96 grams of Ni for a total of 773 grams of base metals. GSP's numbers of 120 grams of Cu per liter of 50/50 project that my 3 qts (2.85 liters) of nitric should dissolve 684 grams of Cu. That is awfully close to my 677 grams plus I've gotten the 96 grams of Ni as a bonus.
Any suggestions/comments? It looks like it's time to retire this solution or add some more fresh nitric. I'm hesitant to do that as I wanted to save some for misc. small projects without having another whole gallon around, but I'm into this deep enough that I'll probably use another gallon.
I started a new CuCL2 etch going yesterday. It is not exactly AP precause I didn't use any Peroxide. Instead I used only HCl that I washed some corroded copper in. I'm using a bubbler and it's pretty well etched in 24 hours. I may do the rest of the boards in CuCL2 etch.
I also took another look at GSP's post on AR above in this thread plus today's post where Oz dripped in nitric to really pin down nitric needed per unit of gold. I now realize it would have been much more efficient in nitric use to go directly to AR, but would gold dropped from a solution heavy in Cu and Ni have produced fine enough gold? I don't think so from what I've learned on this forum.
Another factor. Some of the boards got a bit contaminated with rodent urine and I suppose that contains some salt and Cl ions so I may have had a bit of gold dissolved.
FrugalEE
When the ones in solution are finished I will have dissolved about 677 grams of Cu and 96 grams of Ni for a total of 773 grams of base metals. GSP's numbers of 120 grams of Cu per liter of 50/50 project that my 3 qts (2.85 liters) of nitric should dissolve 684 grams of Cu. That is awfully close to my 677 grams plus I've gotten the 96 grams of Ni as a bonus.
Any suggestions/comments? It looks like it's time to retire this solution or add some more fresh nitric. I'm hesitant to do that as I wanted to save some for misc. small projects without having another whole gallon around, but I'm into this deep enough that I'll probably use another gallon.
I started a new CuCL2 etch going yesterday. It is not exactly AP precause I didn't use any Peroxide. Instead I used only HCl that I washed some corroded copper in. I'm using a bubbler and it's pretty well etched in 24 hours. I may do the rest of the boards in CuCL2 etch.
I also took another look at GSP's post on AR above in this thread plus today's post where Oz dripped in nitric to really pin down nitric needed per unit of gold. I now realize it would have been much more efficient in nitric use to go directly to AR, but would gold dropped from a solution heavy in Cu and Ni have produced fine enough gold? I don't think so from what I've learned on this forum.
Another factor. Some of the boards got a bit contaminated with rodent urine and I suppose that contains some salt and Cl ions so I may have had a bit of gold dissolved.
FrugalEE
Attachments
Nice job.
If you think you have some gold in your solutions you can test with stannous to confirm.
If you have add some copper sheet,if the acid is spent add a touch more and that should cement out any gold which you can add to your foils.
If you don't want any more nitric and your happy using hydrochloric to strip the foils you can also use it mixed with bleach,Chlorox,to dissolve your gold foils and complete your refining.
If you think you have some gold in your solutions you can test with stannous to confirm.
If you have add some copper sheet,if the acid is spent add a touch more and that should cement out any gold which you can add to your foils.
If you don't want any more nitric and your happy using hydrochloric to strip the foils you can also use it mixed with bleach,Chlorox,to dissolve your gold foils and complete your refining.
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I expect not. So long as there's any base metal present, even if traces of gold go in to solution, they are immediately cemented by the base metal. Of course, it will no longer resemble gold as you know it, but will be found in the bottom in the way of a dark brown to black powder. I suggest you collect all solids that come from the solutions from this project and process for values.FrugalEE said:
Harold
Nickvc,
Thanks. I did poke a piece of copper into my wash water the other day to see if I would get gold or possibly something else not considered and it just got shinier. The same thing would happen if I put it in the main etch tank. See Harold's comment. I think I will be processing these foils in a variety of ways including the HCL/Clorox method to gain the experience. This is far more about the learning than trying to make money. I still haven't mixed the stannous chloride and played with it yet. I'm lookng for a decent eye dropper & bottle combination among my junk.
Harold,
You're right of course about the base metals, copper and nickel cementing out the gold. I was looking at my copy of that series yesterday, but it never dawned on me how it applied to my main etching operation.
I have to admit that I have no idea yet what the bottom of that pail looks like, but I'll sure process it just like the foils. I expect it wouldn't have quite the purity that the foils have. There may be some base metal sticking to the gold that came out, but if exposed it should redissolve when the pail is agitated.
This little fail safe makes nitric even more of a process that insures you can always see your gold in solid form.
Thanks,
FrugalEE
Thanks. I did poke a piece of copper into my wash water the other day to see if I would get gold or possibly something else not considered and it just got shinier. The same thing would happen if I put it in the main etch tank. See Harold's comment. I think I will be processing these foils in a variety of ways including the HCL/Clorox method to gain the experience. This is far more about the learning than trying to make money. I still haven't mixed the stannous chloride and played with it yet. I'm lookng for a decent eye dropper & bottle combination among my junk.
Harold,
You're right of course about the base metals, copper and nickel cementing out the gold. I was looking at my copy of that series yesterday, but it never dawned on me how it applied to my main etching operation.
I have to admit that I have no idea yet what the bottom of that pail looks like, but I'll sure process it just like the foils. I expect it wouldn't have quite the purity that the foils have. There may be some base metal sticking to the gold that came out, but if exposed it should redissolve when the pail is agitated.
This little fail safe makes nitric even more of a process that insures you can always see your gold in solid form.
Thanks,
FrugalEE
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My typical procedure with such material would be to incinerate, then screen, crushing any solids, using a mortar and pestle. I would then give the residue a wash in hot HCl, then a couple rinses with tap water. Only then would I attempt to dissolve the values. Nothing like it for yielding a gold chloride solution that is easy to filter, and free of contaminants.FrugalEE said:
Harold
