First let me say THANKS for this forum.Wish I had found and studied it long ago.I have spent the last several days reading and learning from so much of your combined knowledge and will continue to do so.My immediate problem is this: Thinking this was a moderate to simple set of procedures,reading the ebay -shor blogs,I collected my materials ,70% nitric,36% HCL,Urea,Sodium Metabasulfite (SMB),table salt,filters,5 gal buckets,large qty of sodium bisulfate(baking soda to nutralize any spills,set up outside in a covered but open area,set up several barriers of spill protection and took my best 7 lbs of plated computer scrap consisting of pins,broken ceramic processors,micon connectors,finger bds,etc,all trimmed but I know it still has lots of contaminants like solder,nickle,brass,copper,silver,etc.Ithought the 2 gal of nitric would disolve most that except for the gold and other PGM's not soluable in nitric.After about 2 hours,lots of red fuming,I had a deep ,clear green solution.I split that into 2 -5 gal buckets of about 1 gal ea.and then added 3.5 gal of hcl to each bucket to make the aqua regia.I let it cook over night,filtered out all the solids left from the chips,conn.,and fingers.Solution was still dark green and clear.I added salt thinking the silver would precipatate like cottage cheese.Nothing really happened.I then got the bright idea to throw in a couple of 2 lb copper heat sinks,remembering how I had read that copper would help to drop silver and gold if in solution.I did this with both buckets at the same time.Nothing much happened for about a minute,then both buckets violently boiled over with a brownish foam.They wouldn't stop,so i figured i had to get the copper out.I had my gloves,mask ,and apron on,so I grabbed the bucket and poured it out into another bucket,leaving the copper heat sinks behind.I lost 1 to 2 gal of solution and whatever was in the foam.I nutralized the spill with backing soda and washed the whole area down with lots of water.The heat sinks were 1/2 gone,figuring there was still lots of copper in solution,I slowly added some pieces of alum to hopefully drop the copper and whatever had attatched to it.They boiled away quickly.I filtered the solution in coffee filters.Had about 5 with some brown percipitant caught in them,but almost no percipitant in the bottom of the bucket.I added urea slowly,in dry form.It fizzed away after about 2 lbs was added.Solution was now brown.I slowly added the sodium metabasulfite which foamed yellowish with each addition.After about a pound and a half,the reaction stopped with the yellowish foam.I let it sit over night,thinking I would get my gold drop.The next day,still brown,no drop.I now had almost 2 full buckets of solution.I took half of one bucket to work on.I figured I had silver stopping the gold from being disolved in the AR,so i thought adding more nitric would solve that problem.I added about a quart,slowly.I started getting a reaction of a bright green slime/foam that didn't disapate.I spooned it off into another container,where about a gal of it still is.After the nitric produced no more green slime-foam,solution was back to green,i added more urea to kill the nitric.Solution turned back to brown.I heated part of the solution,about 3 quarts,to boiling,added SMB ,this time disolved in water.Still no drop after several hours.Tried putting ice in it,no help.I divided that whole mix into 4 seperate cups and added HCL to one,water to one,bleach to one and heated the last one.Tested each with a few bits of urea,to make sure the nitric was nutralized,added more SMB to each.Noticed the one with the extra HCL had a little black ,what looked like mossy mold rise to top.The one with the water seemed to stratify in layers,with the bottom being darker.The one with the bleach added,turned from dark brown to very light brown/green tea color,but no percipitate in bottom of cup.The heated one seem to statify ,going more dark towards bottom,and a little percipitate in bottom.I tested all the solutions with DMG,after the bright green foam appeared.All mixes showed purples and blacks,some more yellow and brown.After the division of the 4 cups,the HCL add cup showed very black as did the heated cup.The other 2 were just kinda greenish/brown.No purple showed after the 4 way division.
I now have many buckets and cups and containers of solutions,haven't thrown anything out,hopefully have not lost too much PGM's,have used up lots of acid and chemicals and still have nothing to show for it.After my readings today,i may try adding some iron to the 4 samples and try to pull out contaminants,but other than that,I don't know which way to turn.I do know now,I have done many things wrong,need much more education on these processes,I dont want to make my mistakes worse,but really need to deal with all these buckets of acid all over the place.I want to learn the correct processes since I have several hundred pounds of material to process.and don't want to send it off to a refiner as I have in the past. Thanks in advance for any tech help you can give me in dealing with this small crisis.
I now have many buckets and cups and containers of solutions,haven't thrown anything out,hopefully have not lost too much PGM's,have used up lots of acid and chemicals and still have nothing to show for it.After my readings today,i may try adding some iron to the 4 samples and try to pull out contaminants,but other than that,I don't know which way to turn.I do know now,I have done many things wrong,need much more education on these processes,I dont want to make my mistakes worse,but really need to deal with all these buckets of acid all over the place.I want to learn the correct processes since I have several hundred pounds of material to process.and don't want to send it off to a refiner as I have in the past. Thanks in advance for any tech help you can give me in dealing with this small crisis.
