Non-Chemical Tin and lead are present

[golddie]

Procedure when Tin and lead are present-Acid Method
page 72
This is from the Hoke book.
She says

cover the articles with full strength hydrochloric acid,and heat to boil until solder loosens and can be scraped off

pour off acid and throw it away

I was wondering how to remove the lead and tin from the solution and make it safe to throw away.
Thanks

 

[butcher]

lead chloride is insoluble in water,
most of the lead will settle in the acidic solution, decant liquid, sodium hydroxide will neutralize the acidic solution, a neutralized solution of HCl + NaOH --> NaCl + H2O,
here Hydrochloric acid + Sodium Hydroxide changes into sodium chloride (table salt) + water, the metals that needed the acid to stay in solution will also precipitate.

there is a good discussion on this on forum "Dealing with waste" 4metals had some good information on this,

Goldie :I am glad you are searching for proper methods to deal with your waste, It shows responsibillity.

 

[golddie]

Hi butcher
Thanks for that reply
I have always think about our eco-system

 

[hemicuda]

The part about what Hoke says in regards to the tin and lead is that it can be softened up and scraped off with acid.....the only catch to this statement is that she was working with larger jewelry grade pieces that could be handled readily, possibly?

We get the joy of having to deal with tiny tiny little pins from scrap computers and such...lol

I have read that lead acts as a type of solvent with gold,kind of in the same way that Mercury does, where it holds the gold suspended in the lead.

If i am wrong I will stand corrected.

Keith.

 

[butcher]

In a melt lead will collect gold, and small amounts of gold do dissolve when solder is used on it, you can retrieve gold from lead with nitric acid, or with the bone ash cupel,this is the technique's they use in an assay when using lead in the melt as a collector,