Sciencemadness Discussion Board

Please help a struggling student with a school project.

dale_wilson69 - 1-12-2007 at 00:46

Can you please direct my email to anyone that can help me.

Our professor gave us 1 KG of this already processed concentrated material.
It contains the following:
Cu-Copper with 8.19 %
Pb-Lead with 6.31%
Fe-Iron with 6.73%
Ag-Silver with 0.041%
Au-Gold with 0.10%

We are to extract each material to it pure form. I need some serious help. Can anyone please tell me the step by step how to do this? In very simple, basic descriptions.

Thank you so much ahead of time.

Sincerely yours

Dale Wilson
dale_wilson69@hotmail.com

[Edited on 1-12-2007 by dale_wilson69]

[Edited on 3-12-2007 by dale_wilson69]

concen_01.JPG - 38kB

12AX7 - 1-12-2007 at 01:02

0.1% gold in 1kg? Just given to you?

Just drop the course and run off with your riches! :P

Let's see...
1. Rude to ask for e-mails.
2. Rude to ask for homework. Hell, you didn't even show the slightest inkling of working this problem for yourself first! What kind of a freeloader are you?
3. If you're in a class this late and you don't even know how to get started on this problem, you deserve to fail. You should've actually gone to class instead of partying.

Tim

not_important - 1-12-2007 at 05:02

You also left out what form the metals are, and what else might be in there. Are you expected to do a full recovery on the entire kg, or can you use some up trying out different methods? Are the gold and silver in an alloy together? This makes a difference on how to proceed.

Blind Angel - 1-12-2007 at 07:42

Disolve all that in aqua regia, extract everything from there by neutralisation then reprecipitate every metal according to it's own solubility, (For that you'll have to search though) then filtrate each separately. Fun assignement i think to be honest.

BromicAcid - 1-12-2007 at 09:21

Riches 12AX7? 0.1% of 1 Kg comes out to 0.03215 Troy ounces and at the current asking rate of $783.10 / Troy ounce that brings the total gold value to $25.17, worth extracting, maybe if you had a good way to do it, but even then you are going to take a hit on your selling price unless you get the material assayed and then it will still sell for below spot. And of course there is even less silver in it.

Dave, if you wouldn't mind or if one of the mods could do it, shrinking up your picture would help make this thread more readable.

So, this is process concentrated material, like an industrial waste? Or was it concentrated toward some end purpose? Are these the only elements in the material and we are to assume that the remainder of the weight of the material comes from the anions tying them up? There are many ways to approach this, I just have to wonder if this is for school is this some kind of metallurgy class?

I would recommend using quantitative analysis techniques to get your gold and silver considering their low content. With them out of the way you can focus on your iron, lead, and copper. Those seem like they would be easy enough to remove from the solution depending on your method of attack.

[Edited on 12/1/2007 by BromicAcid]

UnintentionalChaos - 1-12-2007 at 09:27

Although I am not well read on the subject, could this be the concentrated extract from circuit board processing? The presence of silver, gold, copper, and lead all at once would make a lot of sense if it was.

roamingnome - 1-12-2007 at 09:45

quickly use a magnet to grab the iron though......

use a torch to actually distill the lead...

12AX7 - 1-12-2007 at 10:59

The percentages don't add up to 100%, so I wonder how much of it is gangue, and of what kind. Especially if it's siliceous, fusing with a flux and reducing agent would be an excellent first step. Some copper may be needed to dilute the mixture. This puts it in metallic form, which can be dissolved in nitric acid, leaving the gold as a precipitate. From there, the acid can be cooked off or neutralized and the silver cementated with copper metal, then the copper precipitated as metal or Cu2O with a reducing agent (citric acid, aldehyde, etc.). Sulfate will precipitate lead. This leaves iron in solution, which can be isolated by oxidizing to Fe(III) and neutralizing, precipitating the highly insoluble Fe(OH)3. Spectator ions (alkali from neutralization, nitrate, sulfate, etc.) remain in solution with a few ppm of leftovers, mostly lead.

Tim

Sauron - 1-12-2007 at 19:11

It does sound a lot like mix of metals extracted from PCBs, electronics waste. Heavy on Cu, Pb, Fe, traces of Ag and Au.

not_important - 1-12-2007 at 19:56

But missing tin, which you would expect from solder. It could have already been de-tinned but that's difficult with traditional solders I believe.

If there are no metal halides, carefully roast the stuff to oxidise the base metals to their oxides. Extract that with acetic acid, treat the extract with ammonium sulfate to precipitate the lead. Add H2O2 and heat, then make alkaline with ammonia; iron falls out as Fe(OH)3 while copper remains in solution as the complex.

If the silver and gold are not in an alloy, treat the solid with nitric acid to dissolve the silver, then use one of the common methods to dissolve the gold.

But without knowing what form the target elements are in, and what else is in there, this is all speculative.

Sauron - 1-12-2007 at 20:15

Yes, there really is not enough data to design an intelligent seperation sequence, really.

The percentages do not add up to anything like 100, so other metals COULD be present. I am not married to the stuff being electronics waste, but the alternative would be that the teacher made this stuff up for the assignment, and using electronics waste instead would be simpler and easier, also cheaper!

While the noble metal reactivity is markedly different the amounts of Ag and Au are trivial and that complicates their isolation.

Fe, Cu and Pb, I think these are the easier parts. There's plenty of them and seperating them from each other is not so hard.

UnintentionalChaos - 1-12-2007 at 20:16

Silver will dissolve out with the ammonia too...diamminesilver (I) cations...

dale_wilson69 - 3-12-2007 at 03:24

Hello Everyone.

Thank you so much for replying. I am sorry you feel that way Tim. I did some experiments, but it not working out so well.

1st: I used sodium 1:1 ratio with the concentrate then heat it up to 500 degree cel. for 2 hours then filter it through with water that extracted 50% of the copper. I was hoping a better way.

I should have been more clear.

Cu-Copper with 8.19 %
Pb-Lead with 6.31%
Fe-Iron with 6.73%
Ag-Silver with 0.041%
Au-Gold with 0.10%
Is from 1 tonne of concentrate. I was given only 1Kg of it.

Thank you again so much everyone.

Dale

not_important - 3-12-2007 at 04:38

From that other new thread, this appears to be concentrate of a mixed sulfide ore. Oxidation of the sulfides is pretty common, with the problem of lead ending up as the sulfate and deciding where you want the iron to go..

There are several better methods than the one you selected.

dale_wilson69 - 3-12-2007 at 05:08

This concentrate is not from circuit board processing. They are from process oxide and sulfide ore.

How much ammonia do I need to dissolve the Silver if I had 1 tonne of the concentrate?

dale_wilson69 - 3-12-2007 at 05:25

Sorry I made a mistake.

How much ammonia do I need to dissolve the Silver if I had 1 Kg of the concentrate?

dale_wilson69 - 4-12-2007 at 19:53

Hello Everyone I found out more detail on the concentrate.

Background:

This pre-processed concentrate is from a mixed of oxide and sulphide ore, from a mining processing company. The readings are % per tone of concentrate.

I used an NITON XLt XRF and got these readings.

Nb – 0.103, Zr – 0.012, Cu – 9.38, Pb – 7.28, Zn – 0.103,
Fe – 7.34, Mn – 0.070, Ti – 0.684, Ag – 0.063, Mo – 0.002,
Au – 0.020, Co – 0.062, Pt – 0.075

Other materials were below readable levels.

I experimented the following:

COPPER
1. I mixed the concentrate with sodium chloride 1:1 ratio then heated to 644 degree Fahrenheit or 340 degree Celsius, for 2 hours.
2. I then filter it through water, but I was only able to extract 50% of the copper.
Question #1: Is there a better way to extract the copper from the concentrate to get near 99% extraction?

3. I was going to direct electroplate the copper from the solution with 15% sulfuric acid, to get 99.99% pure copper.
Question #1: Would it be better to running it through an SX plant?
Question #2: Can I use reverse osmosis to clean the 15% sulfuric acid, back to clean the water and reuse the water again?

LEAD
1. After letting the concentrate dry. I was going to mix 10 – 12% coconut carbon with the dried concentrate then heat it up to 360 – 368 degree Celsius to extract 99.99% pure lead.
Question #1: How long do I heated for?
Question #2: Is that the proper mixture for the coconut carbon?


SILVER
1. After the lead process. I was going to mix Borax – sodium tetraborate - Na2B4O7, Silicon dioxide - SiO2, and Sodium fluoride – NaF and heat it up 1,000 degree Celsius to extract 99.99% pure silver
Question #1: What % mixture from each chemical is needed per tone of concentrate?
Question #1: How long do I heated for?

I would like to extract the Pt, Ti and Fe, but I do not know how.

From the reading of Mn, Co and Nb are they high enough in % per tone to try and extract it?

Thank you so much ahead of time.

Dale

not_important - 4-12-2007 at 20:49

Metallic lead will dissolve silver and gold.

dale_wilson69 - 4-12-2007 at 20:51

I just search google, but no info on getting or making metallic lead.

dapper - 5-12-2007 at 18:32

Maybe his point was that heating the mixture could cause gold and silver to dissolve in the molten lead?

not_important - 6-12-2007 at 20:47

Quote:
Originally posted by dale_wilson69
...
LEAD
1. After letting the concentrate dry. I was going to mix 10 – 12% coconut carbon with the dried concentrate then heat it up to 360 – 368 degree Celsius to extract 99.99% pure lead.
Question #1: How long do I heated for?
Question #2: Is that the proper mixture for the coconut carbon?
...


Sounds like you intended to reduce to metallic lead, which would also likely pick up silver and gold, leaving little in the residue for further processing. Once upon a time the Pattinson and Parkes processes were used to recover the silver dissolved in lead.

Magpie - 6-12-2007 at 20:55

The classic fire assay recovers silver and gold from a lead amalgam. But this is done on a very small scale and may not work in your case. How many grams of lead, mg of silver, and mg of gold would be in the lead amalgam?

[Edited on by Magpie]

not_important - 6-12-2007 at 21:58

Fire assay converts the lead back to oxides, which at the best have a high loss rate, so that's not really practical if you also want to recover the lead. Thus the Pattinson and Parkes processes, which produced desilverised lead, and silver as the metal or rich alloy.

There's no mercury involved in what they were proposing to do, thus no amalgam. By the percentages given in the starting post 63 (Pb) : 1 (Au) : 0,4 (Ag), the lead produced from the concentrate would likely have a nit lower amounts of the precious metals.

Magpie - 6-12-2007 at 22:50

I thought the word "amalgam" was just another word for alloy or solid solution. I didn't realize it only applied to solutions with mercury. Thanks for the correction.

If the final solid solution of Pb, Ag, and Au contains 63g of Pb, 0.4 g of Ag, and 1 g of Au, then I would think that the fire assay approach might indeed provide a separation. But if, as you say, the lead oxide losses are too great, then, scratch that idea.

dale_wilson69 - 6-12-2007 at 23:42

Is fire assay the only solution? Can I do separate electrowinning for each of the material?

not_important - 7-12-2007 at 00:12

Fire assay does not really work, if you reduce the lead to the metal you could electrorefine the lead to recover the precious metals it picks up. There's been several alternatives suggested. Electrowinning takes getting the metals into solution, and that's the real issue. You could just heat the stuff with HNO3 to take everything but gold into solution, but I doubt that it would be easy getting selective enough to get good separation.

dale_wilson69 - 8-12-2007 at 22:35

Anyone with more idea's that can help me. Thanks.