addition of active carbon into an ar solution

[arthur kierski]

i had a dirty ar solution with gold ,pd and base metals----it was tested with stanous and the result was pms------- To the solution i added active carbon and heated for a few minutes with stiring --then i filtrated the solution with the carbon and tested the solution for pms--the result was barren ----that meant that all the metals (base and pm)where adsorbed by the carbon----the adsorved carbon (very black) was heated at 500centigrateds in the presence of air in a small furnace with the door half open---- after 20minutes the black powder became brown,all the carbon went out as co2------now i had a brown powder with the pms and the base metals----how would one treat this powder to obtain the pms?
thanks for any ideas,sugestions-----
the barren ar solution became light green---is this the collor that should remain? i thought that it would looks like water collor,like when precipitates with zinc
thanks
Arthur

 

[butcher]

Arthur,
First I would treat it as if it had tin and lead.
(If none of these or only very small trace of lead, tin or aluminum you can go straight to nitric treatment)

You have roasted so we should be good there, if they were not brought up to red heat I would re-roast to get powders glowing red hot but not melted.

(Roasting removes last acid that formed the salts like chlorides; it also will oxidize the metals making the go into solution easier or tin to dissolve easier in hot concentrated HCl).

Boil in HCl, lower temp to medium, add a little water to dilute some, let powders settle (keeping solution very warm but not moving to disturb powder decant hot solution not disturbing powders, (this solution of base metals let settle any powder should be suspect of some very dirty value), again add water and let rinse heat decant while hot and powders are settled well, repeat hot rinse, (if these were highly colored I would repeat these steps.

(HCl will dissolve many of the base metals, including Copper oxide, and the tin oxide, it will also form lead chloride, (any aluminum will dissolve and as long as solution did not have too much aluminum, it wouldn’t gel bad), the hot water will dissolve lead chloride).

Dry on low heat crushing stirring powders before dry (salts may fuse to syrup and need more heat to dry), keep heat as high as possible without bubbling spitting or splashing.

Roast red hot to remove chlorides used in last process.

The dry powders should now be free of most tin, lead, aluminum, copper, and most of the base metals.

Now we can treat with nitric acid.

 

[arthur kierski]

thanks Butcher---i will pass the results----i suspect some pdo in the incinerated brown powder
regards
Arthur

 

[samuel-a]

i suspect some pdo in the incinerated brown powder

Me too. It will probably report in the HCl leach...