Sciencemadness Discussion Board

What caused the copper to precipitate as sheets?

Mabus - 4-2-2015 at 12:22

After etching the copper from some circuit boards with FeCl<sub>3</sub>, I decided to reduce the resulting copper(II) chloride with some steel rods from some lever door handles (I have many to spare), as I've done previous times. The copper would precipitate as a powder or short needles, but a few times it precipitated as sheets, with a sintered-like aspect and very fragile. One time however, the copper sheets were thick enough to not crumble when dry. My last reduction I did a few days ago also yielded some copper sheets.


Does anyone have any idea why the copper would sometimes precipitate as sheets?
Could it be impurities? The electronics I etched also contained solder, and given they are old ones, they must have tin-lead.

Zombie - 4-2-2015 at 14:20

I found this PDF on Spangolite. It's a copper sulfate sheet crystal...
http://www.minsocam.org/ammin/am78/am78_649.pdf

I didn't read thru the entire PDF but I believe it applies.


[Edited on 4-2-2015 by Zombie]

blogfast25 - 4-2-2015 at 15:15

He's talking copper (Cu(0)), not copper sulphate, Zomb.

Mabus - 4-2-2015 at 15:59

I didn't have any copper sulfate, so I don't think that applies.

Hawkguy - 4-2-2015 at 16:04

well shieeet thats crazy

Zombie - 4-2-2015 at 16:17

Admittedly I have a limited understanding of this.
My thought in posting the PDF is perhaps there is something that can tie Mobus;s method into the the formation of these sheeting crystals.
Obviously there is some anomaly at play to " sometimes precipitate as sheets".

I'll catch up... No doubt.

blogfast25 - 4-2-2015 at 17:17

If the "steel rods from some lever door handles" are indeed flat surfaced then the copper will deposit on them as "sheets", which will eventually flake off. This will happen if the rate of copper formation is slow (low reagent concentration, e.g.)

'Nothing to see here', as far as I'm concerned...

[Edited on 5-2-2015 by blogfast25]

Zombie - 4-2-2015 at 18:45

Nice.

42933-2.jpg - 11kB

blogfast25 - 5-2-2015 at 07:37

Caption competition:


'The blueprint for a set of 'ear speakers' that connect straight through the wearer's head. Volume adjustment knobs can be seen.'

[Edited on 5-2-2015 by blogfast25]

maleic - 5-2-2015 at 19:41

Maybe it is just dirty..... Okay, In fact, I don't know the answer


Zombie - 5-2-2015 at 19:52

The whole time I was looking right at the square stock in the Picts. I assumed it was part of the crystal structure...

Should have used Captain Obvious, rather than Competitive.

Maybe it just compacted as per BlogFast.

blogfast25 - 6-2-2015 at 03:53

Quote: Originally posted by Zombie  

Maybe it just compacted as per BlogFast.


If you run this plating business in the right conditions, the copper simply sticks to the substrate. IIRW, electrolytic chroming is done on an undercoat of copper.

[Edited on 6-2-2015 by blogfast25]

Dan Vizine - 6-2-2015 at 17:06

Many steel items are plated with various thin metals to improve durability. Is this pile of steel pieces unlike your usual reductant pieces. Delamination of such a layer may be the cause.

blogfast25 - 6-2-2015 at 19:18

Quote: Originally posted by Dan Vizine  
Many steel items are plated with various thin metals to improve durability. Is this pile of steel pieces unlike your usual reductant pieces. Delamination of such a layer may be the cause.


And if these steel bars aren't too clean that is even more likely to occur. Bits of oil or grease easily ruin adhesion of the Cu coating to the steel.