something that bothers me

[arthur kierski]

i have plenty of fantasy jewllery made with brass and plated with precious metals like gold,palladium,silver and some with rhodium------------------------------------------------------------------
what i do:i take 1kilo batches and dissolve with nitric (70%)diluted to 35%.to dissolve base metals and ag +pd in the solution-----what remains,is a greysh powder containing gold ,some pd cemented and some agcl in the form of agcl and rh if present in the plated jewellery--------------- the remains(average) 35 grams per kilo----
i take this 35grams and dissolve in ar and obtain 0,8 grams of gold +0,4grams of pd (which was cemented in the 35grams powder) and remains in the ar leached solution around 8to 10grams of powder with some agcl and rh(if present)-------what bothers me is that in my mind the powder left should be no more then 1gram of agcl and rh ------what is the 7 to 9grams left after the whole process-???-------example:in 100kilos of these jewllery ,i obtain 80grams of gold,50grams of palladium ,50grams of silver---and 700grams to 900grams of this powder------
what bothers me and is not understandable(to me) is this powder that always remains
thanks for replies
Arthur

 

[samuel-a]

Arthur

Any chance some of the items consist of bronze as base metal?

 

[4metals]

Samuel may be correct, you may be looking at tin.

 

[Palladium]

Couldn’t he incinerate and do an hcl wash to find out?

 

[4metals]

Yup, Just roast it with a torch and try to digest in in HCl

 

[arthur kierski]

although i do not think that the base metals might be bronze----i will roast (incinerate) the material and leach it with hcl-----i will see what happens and will tell you what happened.
thanks for the moment,
Arthur

 

[arthur kierski]

dear friends,i did all the recomendations given to me and the powder left did not dissolve in ar----i realized that is not bronze(no tin)-----it might be white bronze=copper +si----tomorrow i will try to dissolve the( si)?and then ar again-----
any more ideas?
thanks,
Arthur

 

[Palladium]

Maybe a run in hot Sodium Hydroxide?

 

[samuel-a]

Arthur

white bronze could also be Cu+Sn+Zn with no Si.

Try and react some of the white/gray powder hot 50% sulfuric acid solution, if partially /completely dissolved, then most likely it is H2SnO3.

 

[arthur kierski]

Samuel,i will try as you mentioned----50%h2so4 +50%h20---hot--------i hope it is not silica---if si i will have to use or hot naoh(palladium recomendation) or hf(my last hope)
regards
Arthur

 

[arthur kierski]

i did the 1to1 hot h2so4 and the powder was reduced by 5%in weight----with nacl it gave agcl and the liquid became green and with potassium ferrocianide it gave prussiam blue=fe---------------
to the powder left i used ar and the stanous test gave a little pd------- in resume :began with 70 grams of powder and i have now 64grams----a pifious result--------.
thanks and regards
Arthur

 

[glondor]

Pifious is a good word. I like it. What does it mean? Contemptuously marginal?

 

[arthur kierski]

pifious means very small results----ridiculous results---next to nothing