Ardibash
Well-known member
Hello,
I have a pile of gold plated boards and pins taken out from laptops and mobile phones.
I have treated them with boiling Hydrochloric acid to remove all solder.
Here are 2 questions I have and nay feedback would be much appreciated.
1: After boiling in HCL I have some very fine black powder deposited on the gold plated parts (can't see gold anymore) and mixed in the solution. When rubbing I can expose the gold, and the powder blackens my hands when scrubbing off the SMBs (I touch them only after it's treated with saturated sodium bicarbonate solution).
Is this black powder the silver from solder?
2: A friend recommended a recipe of dissolving only gold from this material. 1000 ml of concentrated Sulphuric acid (H2SO4) + 80ml of Aqua regia, this will dissolve the thin layer of gold, after the acid is saturate or neutralized, the gold can be precipitated with diluted Hydrazine hydrate. has anyone tried this method?
P.S.
Can I recover the evaporated HCL with Distillation Condenser?
I have a pile of gold plated boards and pins taken out from laptops and mobile phones.
I have treated them with boiling Hydrochloric acid to remove all solder.
Here are 2 questions I have and nay feedback would be much appreciated.
1: After boiling in HCL I have some very fine black powder deposited on the gold plated parts (can't see gold anymore) and mixed in the solution. When rubbing I can expose the gold, and the powder blackens my hands when scrubbing off the SMBs (I touch them only after it's treated with saturated sodium bicarbonate solution).
Is this black powder the silver from solder?
2: A friend recommended a recipe of dissolving only gold from this material. 1000 ml of concentrated Sulphuric acid (H2SO4) + 80ml of Aqua regia, this will dissolve the thin layer of gold, after the acid is saturate or neutralized, the gold can be precipitated with diluted Hydrazine hydrate. has anyone tried this method?
P.S.
Can I recover the evaporated HCL with Distillation Condenser?