Puff501 said:
Some very experienced people in this forum may well know what the contamination is and may be able to advise.
Sorry for the delay in responding --- based on the second pic (bottom of the bar) copper - & lots of copper at that
First pic (top of bar) looks like "possible" other contamination (iron, nickel, etc. etc.) --- or could be (just) more copper as "oxides"
I say that because in the third pic you can clearly see the copper on the (upper) edge of the bar - so the very top of the bar could be just more copper as copper oxides - or combination of copper along with "some" other base metal contamination --- what ever the case - copper is the main contamination - & it looks like a lot of copper
Also on a re-refine, Should I start from the beginning with inquartation
so you used inquartation in the first place
Based on the amount of copper contamination I "assume" you used copper to do your inquarting --- or did you use silver :?:
Also - based on the amount of copper contamination I see - I "assume" you only did "one" hot nitric leach to remove the copper (&/or silver) & then "some" water washes --- is that right :?:
When doing the inquartation method/process you will almost never (if ever) get all the copper (&/or silver) out with the first nitric leach --- just like with gold dropped from a normal AR drop you need to put the gold sponge through hot water & acid washes to rid the gold sponge of contamination --- how many washes will depend on contamination left behind in the first leach (inquartation leach) or the first gold drop (from AR)
Lets stick to inquartation - with copper as the inquarting metal - you need to do hot "boiling" (as in a simmer boil) water washes (boiling forces the copper nitrate "out of" the sponge) you need to do those washes until you see NO blue in the washes (in other words it can take 3 or more hot (boiling) washes to get all the copper nitrate out
But you are not done yet because you may not of dissolved all the copper in the first leach - therefore you need to do another hot nitric (simmer boiling) leach to insure all the copper was dissolved in the first leach
If you get a blue solution in this second leach/wash you did not get all the copper the "first" time --- so you will have to do the hot water washes again - & then another hot nitric wash followed by hot water washing
In other words - you need to do the water washing (after first leach) followed by an acid washing & you need to do that how ever many times it takes until you get no blue out of the acid wash --- keep in mind that after each acid wash - you need to repeat the water washing until all the blue is gone from that acid wash
normally - it takes at least 3 acid washes to get all the copper out (& can take even more)so you do the acid washing until you get an acid wash that produces no more blue --- & like wise each of the water washes need to be done till the blue copper nitrate is washed out
Inquarting with silver --- you need to go through the same washing process - except that you need to test each wash with HCl or salt to insure you have washed all the silver out --- in other words - the HCL or salt will produce silver chloride (which will appear as a white cloud) so you need to do the washing until NO silver chloride cloud is produced when you test the washes with HCl or salt
It is possible to get all the copper (or silver) out in the first leach (thought that is "rare") so no mater what - you always have to at the very least do at least one acid wash (after first water washing) to insure all the copper/silver came out in that first leach
or would I just go to the aqua regia step over again
That is what I would do - at this point there is likely very little silver left - so I would re-melt the bar & pour it to shot/corn flake - the AR will dissolve the gold & copper (&/or other base metals) once you have dissolved the shot/corn flake in AR - there "may" also be "some" dissolved silver in the AR --- so you want to then dilute that AR by 2 - 3 times --- by diluting the AR IF (big IF) there is any silver (small amount) dissolved in the AR - it will drop out as silver chloride when you dilute the AR --- the silver chloride will be VERY fine (you may not even see it) so let it sit for a day for the silver chloride to settle out
Keep in mind that after dropping your gold from your AR solution - you still need to put your dropped gold through the water/acid washing --- if you want clean (pure) gold as your end product --- & you use HCl for the acid washing of gold dropped from AR --- instead of nitric acid to wash gold sponge from inquartation leaching
to clarify - to wash gold dropped from AR - you put the gold sponge through water/HCl washing --- gold sponge from the inquartation process goes though water/nitric washing --- if you want clean (pure) gold
Kurt
