# AR refining issues



## Goldenrod757 (Mar 8, 2021)

I have been mostly refining jewelers polishings, often mixed with varying amounts of floor sweeps. I have used magnets to remove iron but expect that some remains. Most of my refinings have gone well however some have not. Generally I boil down the recovered aurochloric solution a few times to remove nitric content, in preparation for dropping gold with sodium metabisulphite. I am generally careful to ensure the solution are resonably dilute. Most times i have had no issues but sometimes when i am rediluting the boiled mixture i get gold precipitated but also an orange precipitate. It looks like gold mud but it is not. I generally decant it and save it but have not discovered what it is and what to do with it.If my observations are correct , this orange sludge tends to form if i had taken the drying to the state where it gets to be a solid cake (of course i add water and attempt to redissolve the solids ). Any advice would be appreciated. 

Also once I put together and concentrated several small collections of suspected gold bearing solutions and left it sitting in transparent containers. The walls of the (plastic) bottles aquired a grey silvery coating over a few days or weeks. the liquid inside appears otherwise the same. I have never had that before. Any ideas? Thanks.
.


----------



## nickvc (Mar 8, 2021)

I processed many many sweeps and if you only do one recovery the chances are you will not get all the values.
If you do the process perfectly you can get 90% of the gold on the first process, a second recovery should tell you how well you did, ie if you recover much more than 10% you did a poor job.
With polishing sweeps the chances are you are getting some rouge into your solutions even if you incinerate the sweeps, if the precipitate washes off easily with water I wouldn’t worry too much.
The silver grey could possibly be silver chloride as many gold alloys have silver included in the mix which could be what you are seeing.


----------



## Goldenrod757 (Mar 9, 2021)

Yes, I have a tendency to do a mini AR rerun on the remainder of polishings ....and except for one time when my yield was way below expectation - most likely because some of it was not well ground, the AR rerun is usually very low. Whenever the remaining liquid and even wet processed polishings are stored, ultra thin films of gold may deposit slowly, but nothing that is worth any effort without having a great accumulation of the "waste" collected. 
Still I would like some suggestions on what my orange deposit may be and if valuable in any way , how to recover or reprocess it.


----------



## butcher (Mar 9, 2021)

Could you post some pictures?
Colors can look different or be hard to explain, where a picture shows more.
Could it be iron (is it rust-colored), you can test for iron in solution (see Hoke's pg.100)?


----------



## nickvc (Mar 9, 2021)

As I said it’s a good chance it’s come from the polishing media which is very fine corundum powder.
The point I made about the recovery still stands, if you recover 100 grams first pass the chances are you have at least 10 grams left in your material, 100% recovery from sweeps using wet chemistry is almost impossible but if you think you have it all then ok.


----------

