PRECIPITATING BASE METALS

[TOMCAT_7475]

This is my second post on the boards. The first one gave me some good advise and I have recovered some gold. Still have to do the refining, but still have gold. Fascinating how a solid can be turned into a liquid and then dropped out as powder and then melted into a pure form of the metal. I know that is not exactly what happens, but my chemistry terminology is lacking.
Anyway, here is my question. I have a chance to get a 2200 degree smelter. I dissolve the legs from the IC chips in hcl and would like to be able to precipitate the metals to pour into molds. Purity is not an issue although I would like to have the copper separate from the tin,zinc or other base metals that may be in the solution. What is the best way to "drop" these. Also, I have read the forum and have read silver will and silver will not dissolve in HCL. I have been taking samples of the different IC chips, crushing them and taking the metals and soaking in HCL to see what is left after a few weeks. There's one type that has wide copper legs, but also a metal that is completely unaffected by the HCl. Brite, shiney like polished silver. I know from the forum that it could be several different metals. How can I tell which this metal is?

Thanks!!

 

[Lou]

Woah, slow down my friend.

Unfortunately, you will only be able to affect a limited separation pyrometallurgically from such material.

Your best bet is to get good at smelting, get good at fire assaying, and then get really good at brokering.

Generally speaking, most of the metals you're working will just homogenize with each other.


I'm off to do some melting myself!

 

[upcyclist]

If you stick around and read for a while, you'll start noticing people talking about getting rid of their base metals. Some of the really annoying ones (tin) will dissolve in HCL, so if you have a lot of solder, you'll want to do that. Once you've done that, you can look into processing with copper chloride using the AP process. Or perhaps digestion in acids, then cementing out with copper. There's lots of approaches, and the experienced folk around here (not me, btw) know which processes are best for which situations.

When you're doing PM recovery/refining, you really don't want to melt anything until you have pure elemental metals, unless you like making alloys. Even then, you better know exactly how much of each metal you're combining. Are you making a 14K yellow gold alloy? Or just a lump of something that might have some gold in it, which will be harder to refine once it's in an alloyed state?

Smelting is something you probably won't be doing (or at least won't need) on a small-scale refiner level. If you want to buy a smelter (how big of a unit are we talking?), you're probably talking about processing larger quantities of metals. I don't know jack about smelting, but I'm thinking this is more for base metals, steel, or ore processing.

I would guess that two primary options are 1) become a smelter and do small-scale recovery/refining on the side, or 2) become a recovery/refining guy and sell your purified product to the big boys with the smelters

 

[TOMCAT_7475]

Please allow me to clarify my post. I am slightly dyslexic and it made me hate English classes when I was in school 30+ years ago. Therefore I have a hard time putting into words what I mean to say and leave out important details. Fortunately what I lacked in the verbal skills, I made up for in the advanced math and chemistry classes. I have been a scrapper since around the age of 14 after my dad taught me how to earn some money by walking up the river bank getting cans and copper wire along the banks. I have scrapped a many of computer not knowing the value other than the copper and aluminum content. Recently found out about the precious metals also in them.
To clarify my post-- I have gold flakes from fingers and some pins that was dissolved in HCL. Have them in an old blue mason jar almost full of water. Shake it every day or so just to watch them float around. My own little golden snow globe. I have no interest in going any farther with these at this time. It was suggested that I use reverse electroplating on the plated pins. Thanks to this forum, hoke's and you tube I have ran a small batch of plated pins and it seems to have worked correctly. I have plenty more to run, just won't mess with any of this when the grandkids are around.

Lou-- So salvaging the waste material is pretty much out of the question? Purity is no issue with this as long as it will form a solid in the end. Pretty sure I am going to get the furnace. Not that large, but will do anything I planned on doing. I have wanted to get into casting with sand molds for years, just never went through with the initial investment. I thought maybe I could put to use the dissolved waste products. Not a money thing, just a pride thing. "I molded this".

Upcyclist-- Base metals is what I am planning on smelting. As of right now I will keep my gold in flake or powder form. I am more than happy with my golden snow globe. Maybe in a few years I will decide to try my hand at refining. I found a furnace that will get hot enough to do copper. I figure don't need anything hotter than that. There's material around everywhere I can use, just thought it would be nice to do something with the waste instead of tossing


Could someone please help me with the "bright shiny like polished silver" metal left in the HCL? I do not know how to test for the metals it could be.

 

[g_axelsson]

Let me see if I can put this in an easy way...

The more noble a metal is the easier to get it back into metallic form. For base metals it gets harder and harder the less noble they are.

For example, copper we can easily get out of solution by cementing it on iron scrap.

We can even get iron and zinc out of solution by using electricity in the way of electrowinning.

But when we get to aluminum or magnesium we can't get it out of solution as water is easier to turn into oxygen and hydrogen. So in that case we need to go to extreme processes as electrolysis of molten aluminum salts and oxides and it's done in huge industrial complexes.

So to get a dirty copper back from solution, just throw in a piece of soft iron or some pieces out of a computer case and the copper will cement back from solution while the iron is used up.

For other metals do a search on electrowinning (you can get iron and zinc back that way) but it can be tricky to get it working and would include a lot of learning, research and trials.

For the leftovers I would recommend to treat it like waste. Instructions on how to properly treat it is on the forum, look in the library section.

Göran

 

[kurtak]

Could someone please help me with the "bright shiny like polished silver" metal left in the HCL? I do not know how to test for the metals it could be.

Could you provide a pic for use to see what you are talking about ?

I ask because there are only a couple metals used for the wire legs in IC chips - copper or kovar or alloy 42

Also you say you are dissolving the copper with HCl which does not make sense because HCl "alone" does not dissolve copper (or is very, VERY slow at doing so) so are you adding H2O2 (peroxide) to the HCl which then makes AP (acidic peroxide) which dissolves copper turning it to CuCl2 (copper 2 chloride) which dissolves copper

HCl (alone) will dissolve kovar &/or alloy 42 (but is slow in doing so)

HCl also does not dissolve silver - though it can have a slight effect on silver causing "some" silver chloride to be formed

Some of the copper, kovar or alloy 42 in IC chips will have silver plating on it

All of the above is why I ask if you can provide a pic as seeing a pic would help us "see" what you are talking about

Kurt

 

[TOMCAT_7475]

The more noble a metal is the easier to get it back into metallic form. For base metals it gets harder and harder the less noble they are.


Göran

Thank you g_axelsson. That was a simple answer, but exactly what I was looking for. The base metals are way to easy to get anywhere else, no point even spending the time on them. Someone please correct me if I am wrong. The company I work for has a waste disposal company pick up spent oils (a lot of which has metal shavings). I can treat my waste with baking soda to neutralize the acid and it can be poured in with the oil?

Kurtak---- My terminology sucks, I did use HCL and added peroxide to get the start. I will try to get pics up this evening.

THANKS GUYS!!

 

[butcher]

Read up on the post dealing with waste in the safety section, it will help clear up many of the questions you have. Mixing the waste solutions from your processes with waste oil would be a terrible idea.