advice on processing escrap

[micronationcreation]

hi, when initially processing escrap with 50% nitric & 50% water is it normal for the silver nitrate to descend to the bottom of my beaker and mix with the gold, making it very difficult to seperate them from each other?

i am thinking the water i use from the tap may be converting silver nitrate to chloride? is this right?

my ar process is almost perfect thanks to this forum so hopefully this is the last daft question. thanx

 

[4metals]

Yes the chloride in tap water can cause the silver to come out as a chloride and mix with your gold.

You essentially need chloride free water. One way to make it cheaply is to add silver nitrate to water with chlorine in it. A hazy fog will form which is silver chloride but continued additions until no more cloud forms produces chloride free water great for nitric / water dissolves.

I know of more than a few refiners who make their water for silver cells this way, often in 55 gallon or larger tanks. Just take the time to settle out the chlorides.

 

[micronationcreation]

so what would the best way to separate my current batch of silver chloride/gold?

add more nitric or try ar and mix so it gets to all the gold?

thanks for replys. euan

 

[4metals]

If the silver chloride formed separately from the gold it should not pose any encrustation problems in refining with aqua regia.

Just dissolve the gold in aqua regia, filter and drop the gold normally. If the silver was substantial it can be reduced with caustic and sugar or if it is a small quantity reduce it by contacting it with iron.

 

[Harold_V]

I would suggest to you that not everything you think is silver chloride is silver chloride. When you dissolve e scrap in nitric, it's quite common to get a white precipitate (which may or may not be silver chloride).

While I ran very little e scrap, I ran enough to know that what you're experiencing is common. In fact, some of the material is often tin, which is very troublesome in refining. My recommendation to you is to incinerate the entire lot after the nitric digest, then give it a wash in hot HCl before you digest the values. That will help eliminate some of the problem material, but, best of all, typically improves filtration of the resulting solution from the digestion of values.

For the record, I used nothing but tap water for all of my digestion procedures (except for making electrolyte for my silver cell)---I wasn't concerned about the slight amount of silver chloride that was created, for it was eventually recovered when I ran my waste materials in a furnace. The silver chloride became the collector that was sorely needed to capture the metals of much greater value. It worked like a charm.

Harold

 

[micronationcreation]

sound advice thankyou both for replies.