newby first step

[Harold_V]

Here's a trick you might try. I use plastic disposable white spoons as a spot dish alternative. When i have trouble doing a test because of the solution color i test some in a spoon. After the test sits for awhile. How long you ask? Couldn't tell you. It really depends on the gold concentration and how long you let it sit. Overnight is best for low concentrations. I'm usually in no hurry. After it sits for a couple of hours you can wash the test solution off the spoon and if you see a purple stain on the spoon then Bingo !!!

That's very good advice, even when testing with a spot plate, which I prefer, by far, over other methods.

I have tested solutions that were cross contaminated and yielded mixed results by stannous chloride. If there's gold present (in solution), there's no mistaking the purple stain left behind after allowing the test to age somewhat. The stain appears, even when the purple color isn't obvious otherwise.

Harold

 

[callicom]

i always heard there was more than one way to skin a cat, i should filter the rest of my ap today then i`ll do both ways :mrgreen: what is a spot plate :?:

 

[Palladium]

http://www.ebay.com/itm/PORCELAIN-SPOT-PLATE-6-WELL-/230261909406?pt=LH_DefaultDomain_0&hash=item359cade79e

 

[callicom]

a picture is definitely worth a thousand words in this case, thanks for the link. from what i understand the copper can be dropped out of the ap and the acid reused, how do you guys do that :?: , i`ve been reading hokes but i haven`t read of ap or acid clorox yet in there

 

[Palladium]

Once you drop the Copper from ap with steel your solution is spent. The thing to do is if your solution is saturated and the volume has increased from hcl additions or H2O2 is to pour off some of the spent solution and add steel to precipitate the copper. Then you can take the left over solution that you didn’t add steel to and add fresh hcl and bubble air through it to use it again. Or you take fresh hcl and take a cup of your old solution before steel is added and pour it into the new hcl to jump start your reaction. By doing this you don’t have to add any peroxide to jump start the process. All you have to do is add air after that to keep the reaction going. This reduces your overall volume of solution. The only reason you use peroxide in the first place is to oxidize the copper to oxide so the hcl can dissolve it. Once copper is in solution the air from your aquarium bubbler takes over and it supplies the necessary oxygen from the air to keep the reaction going. You can actually start with just hcl and air but the progress will be slow at first until the copper concentration picks up in the solution. Fresh acids don’t always mean faster rates. In this instance the more copper in solution the better because your etch rate will pick up considerably. The only thing that governs the etch rate at that point is the free hcl that exist in the solution. Most people don’t use their ap to completion because they think it is saturated to much. A gallon of hcl will hold about 3 lbs of copper. Not other metals, copper! I love mine saturated and plenty of air.

 

[callicom]

so i just drop a piece of carbon steel in there and what happens to the copper, it just drops to the bottom or does it stick to the sleel :?:

 

[callicom]

also does nitric disolve carbon steel :?:

 

[Geo]

re-use your AP solution only adding fresh hcl due to lose of taking material out and evaporation. i cant remember the name of the effect but bubbling air through a solution causes it to evaporate faster. when the solution turns brown and your batch completes take the material out and leave the bubbler in the solution bubbling and it will go from brown to a deep green. i cant tell you what happens during this time but some of the copper will come out of solution as powder in the bottom of the container, remove this before your next batch.

 

[Geo]

also does nitric disolve carbon steel :?:

nitric acid will dissolve steel. i don't think the addition of carbon to the steel as it is such a low percentage would make any difference. the copper will come out of solution as steel goes in and normally will pile up around the piece you put in. copper will not stick to steel without heat and flux.

 

[callicom]

ok, i`ll just keep some ap for my next batch and drop the rest. this batch i got all the values and burned the hcl out by putting it in a cast iron pan and drying it up, then i passed it through ntric and got the rest of the base metals out. but when i tried to burn the values with nitric in my cast iron pan it rusted right away and turned orange so i got it out of the pan and passed it through nitric again, that why i asked if nitric desolved steel , it looked like it did but i wanted to make sure.
then iput it in a crucible and burned it red hot and i could see and smell the nitric coming out, nice. the crucibles i bought were white porcelin and it fell apart after use, is there some better ones that are reusable :?:

 

[Geo]

did you heat slowly? porcelain will absorb water from the air and if you heat too fast it will cause the porcelain to crack and bust. put it in the oven and heat on low for 15 minutes then turn the heat up to high for another 20-30 minutes to remove the moisture before heating with a torch and then still heat with a torch slowly till it becomes red. this will prolong the life of you crucibles and melting dishes.

 

[callicom]

is this a one time treatment or do you recommend doing this every time

 

[Geo]

every time. but if your melting gold its worth the effort. :lol:

 

[callicom]

yea i know what you mean one of my crucible busted while i was incinerating and i lost some value on the concrete slab ho well i chalked it up to aprenticeship :mrgreen:

 

[Geo]

when i melt i use a large cast iron pot to set my mold and melting dish in. ive worked too hard to get it to that point and watch it fly everywhere.

 

[qst42know]

ok, i`ll just keep some ap for my next batch and drop the rest. this batch i got all the values and burned the hcl out by putting it in a cast iron pan and drying it up, then i passed it through ntric and got the rest of the base metals out. but when i tried to burn the values with nitric in my cast iron pan it rusted right away and turned orange so i got it out of the pan and passed it through nitric again, that why i asked if nitric desolved steel , it looked like it did but i wanted to make sure.
then iput it in a crucible and burned it red hot and i could see and smell the nitric coming out, nice. the crucibles i bought were white porcelin and it fell apart after use, is there some better ones that are reusable :?:

Something doesn't seem right here. Did you wash with water at all?

 

[callicom]

wash with water :?: yes i washed with water but what doesn`t seem right, mayby i didn`t wash enough, could you explain :!:

 

[Geo]

ok, i`ll just keep some ap for my next batch and drop the rest. this batch i got all the values and burned the hcl out by putting it in a cast iron pan and drying it up, then i passed it through ntric and got the rest of the base metals out. but when i tried to burn the values with nitric in my cast iron pan it rusted right away and turned orange so i got it out of the pan and passed it through nitric again, that why i asked if nitric desolved steel , it looked like it did but i wanted to make sure.
then iput it in a crucible and burned it red hot and i could see and smell the nitric coming out, nice. the crucibles i bought were white porcelin and it fell apart after use, is there some better ones that are reusable :?:

Something doesn't seem right here. Did you wash with water at all?

you cant wash acid out of your material with water not even with boiling water. you rinse with water to remove soluble salts not acid. you have to incinerate to remove acid.

 

[callicom]

i just picked up 177 cpu, 52 lb of boards and a couple pounds of memory stycks, i got the whole thing for 380$, i should make a good profit or did i just mess up

 

[jimdoc]

i just picked up 177 cpu, 52 lb of boards and a couple pounds of memory stycks, i got the whole thing for 380$, i should make a good profit or did i just mess up

That depends on what type CPU they are. If they are P-3 and P-4's then you probably paid too much in my opinion. You can check thriftybits.com to see what he would pay, or boardsort.com who seems to pay the best prices.

Jim