Non-Chemical Pic of my Cell

[jmdlcar]

Here what I found so far.

First time electrolyzer de-plating

The following comments are not meant to detract from what you are doing, I'm merely trying to give you a better understanding of what factors are important when using the cell verses which ones are more trivial. Please accept them in this light.

I admire your attention to detail as far as the temperature and electrical parameters of the stripping cell reaction is concerned, but frankly a few degrees Celsius or Fahrenheit and/or minor dc volts or amps variations of your cell will not go to drastically affect the final outcome. If it makes you feel better about getting the reaction 'just right', you can continuously monitor your cell temperature, amps, and volts parameters, but all of it will vary with each and every unique type of scrap you are running.

Think of the gold plated part(s) you are stripping as another unknown (perhaps the biggest) and you will see where I'm coming from. In your quote above you mentioned a particular weight of 'board edge pins, DB sockets, cable connectors, etc...', but you do not specify the manufacturer, year of manufacture, application, base metal, etc. These factors all will affect the yields as well as the results of the observations you are charting, maybe even more so than the temperature, voltage, and amperage. In fact the physical characteristics of the gold plated part may be the biggest contributing factor to the variations you measure and for this reason your values will always be different for each and every unique type of scrap.

In short the generic terms like cold, hot, and 12 v 10 A battery charger are more than accurate enough to get a cell operational and producing gold. If you need a more accurate assessment of the temperatures, then let me suggest these operating conditions for the hobbyist cell set up:

1. Wear goggles, protective gloves, and a good acid resistant apron. Start with your sulfuric acid at room temperature (20C). The sulfuric acid should be of 95% concentration or higher.

2. Use a standard 'manual' automotive charger with a built in analog amp meter (one with a moving needle) that is capable of delivering 12v DC @ 10 amps on a continuous basis. The automatic variety of chargers (with led bar graph amp meters) should not be used. The automatic types contain electronic circuits used to sense the battery condition and control the charging of batteries while protecting them and you from harm. These extra circuits don't 'play nice' (new technical term) with the cell set up.

3. Attach a piece of lead to the negative lead of the charger and hang it from one side of your cell set up.

4. Attach the positive lead (copper alligator clip) of the charger to the part to be stripped, or to a copper basket arranged to hold smaller items in bulk. The size of your cell and consequently the basket size will limit the mass of small items you can strip in one run. Be sure the negative lead has an uninterrupted path to the items to be stripped. Imagine a line of sight (LOS) between the part(s) to be stripped and the negative lead. If this LOS is broken by the copper metal from the front edge of the basket, the basket will act as a shield (aka: farady shield) to the pins and slow the strip time and heat the acid. Once the gold is stripped, remove the part as soon as possible.

I have noticed that the longer a stripped (ie: gold is all removed) part stays in the electrolyte with voltage applied, the more the cell will heat. The energy of the charger is no longer being used to strip gold, instead it is being conducted to the negative lead and generating heat very quickly once the gold is removed. In a perfect world we could calculate the gold yielded from a stripped part by the amount of time required to strip the part in the cell and recording the amount of amps used. In the real world the electrons are conducted along various side paths in addition to being used to strip the gold and we as humans don't remove the part at the exact moment all of the gold is stripped, so the real number of amps consumed is a sum of all of the losses, plus the amps required to strip the gold.

5. Rinse the stripped part in water (or baking soda water) over a container sized as needed for your cell set up. I like to use a spray bottle of straight water, it's quick, conserves water, and the rinse water is always clean that touches the part(s). The rinse pot eventually accumulates a layer of black gold powder on the bottom after extended use followed by a settling period. This black powder is combined with the cell yields.

6. Dab the rinsed part onto a dry paper towel. I like paper towels because they can be burnt to recover any traces of gold in them. One paper towel goes a long way if folded properly and allowed to dry between cell runs. This step is very important to the life of your copper clips and basket. Be sure your clip/basket has most of the water removed from it before placing it back in the cell.

7. Repeat steps 4 through 6 until the cell gets hot to the touch. If you are using a thermometer to determine when your cell is hot, stop when the cell reaches 90C. A cell gets hot for several reasons:

A. Normal stripping of gold.
B. Leaving stripped parts in the electrolyte with the power applied after they have been stripped.
C. Adding water to the cell. Either via air, intentionally, or unintentionally.
D. Your cell is too small for the batch sizes you are running.
E. Shorting of the positive and negative electrodes.
F. Higher amperage flowing per second in a given volume of sulfuric acid.
G. Other factors

Notes:

A. Diluted sulfuric acid, especially when 'hot' (ie > 60C) will eat copper (and many other metals) quickly. Dilution can occur via rinse water trapped on the surface of the anode lead or from absorption through the air.

B. If you rinse your copper clips or basket and do not remove the excess rinse water from the copper before adding it back into the sulfuric acid cell, you are in effect placing your copper into diluted sulfuric acid and will experience a much shorter life cycle for these items. Drying your leads/basket between 'dip and rinse' cycles will greatly extend the life of these parts.

C. Parts must be fully exposed to the sulfuric acid in order for them to strip. Sounds obvious, but a large mass of pins will mechanically shield one another from exposure to the sulfuric acid and the pins on the bottom and inside of the pile will not strip completely or at all.

D. A cell is full and should be cleaned out when the sulfuric acid is saturated with black powder to the point where the powder short circuits the negative and positive leads of the cell when in normal operation. This shorting can occur on the bottom (most common) or on top of the electrolyte as floating blobs of gold and bubbles. Try to sink any floaters with a glass rod to prevent the build up of top floaters. Proper placement of the positive and negative leads can extend the time required between clean outs. The leads should be mounted so that they do not rest directly on the bottom of the cell. Let everything settle for 24 hours before you clean out the cell. You may find the sulfuric acid clears (straw colored to green brown) after the cell settles. This upper layer of acid can be carefully siphoned off for use in the next cell without any further treatment. The black sludge is treated as described in my Black Powder from the Cell post.

You may want to clean out your cell sooner if you want to determine yield data for the scrap in question or you are out of material to process and want to store the cell.

E. The greater the flow of amps in a cell, the greater the number of gold plated parts the cell can strip in the same amount of time. This heats the cell faster as well. The larger the volume of acid in the cell the longer it takes to heat up.


I'm interested in you CCPWM results, but I'm going to predict it will take longer to strip the same parts than with pure DC. The off cycles do not supply the electrons that do the work of stripping the gold atoms off of the part(s). Less electrons in a given time equals less gold stripped in that time.

Steve

And this.

Black Powder from Cell

When your cell is full you should:
1. Let all the black powder settle
2. Pour off the bulk of the concentrated sulfuric acid. Don't worry about the small amount of residual black powder that is in the acid that is poured off as you can get it on the next batch.
3. The remaining acid with the bulk of the black powder in it should be slowly added (let it cool before adding more) to five or six times it's volume of water.
4. Stir this very well and allow to settle again.
5. Siphon off the colored solution. Repeat this process until the wash is no longer colored.
6. Test a few drops of the rinse water with a drop or two of 3% unscented clear household ammonia, if the rinse water turns blue when the ammonium hydroxide is added, copper is still present and more rinsing is required.

7. Dissolve the black powder with AR or HCl-Cl and proceed as typical for these processes.
The concentrated acid that was poured off is used in your next cell run as is. Hot concentrated acid is very dangerous, so exercise extreme caution when handling it. Never add water to concentrated sulfuric acid/powder mixture, add the acid/powder slowly to the water instead.

Steve

I don't know what next.
Jack

 

[Geo]

ok. is there something in that you don't understand? that's pretty much the end.that is the reclamation part of the cell after that comes the refining part. follow the directions above and when you have your black powder rinsed you digest the powder in hydrochloric acid and chlorine bleach. when the powder is dissolved filter the solution into a clean container and you have just made Auric Chloride. after waiting for the chlorine to evaporate you will precipitate the gold using sodium metabisulfite, not bisulfate. the black powder that collects from this process is your refined gold.

 

[Amber]

ok. is there something in that you don't understand?

I have a question about cleaning the siphon hose. Acid to water is the mantra and I understand that is really important with sulfuric. So if I siphon off the acid for re-use after the black powder has settled, how do I safely rinse the siphon hose? I can't seem to think this through so if any one can point me in the right direction I'd appreciate it

Amber

 

[philddreamer]

Hi Amber!
The hose would not contain that much acid to make a big "splash".
I use a big syringe, (from a farm feed store), & squirt some water thru the 1/4" clear hose & into ANOTHER container. Keep that water out of the main acid! I let the sediment in the main container settle for a day or 2, & then siphon; it makes it easier to filter, but one could just start filtering thru several times until the acid is free of sediment. The acid w/sediment can be slowly added to several times its volume of water, (keep track of how much acid you started with); that makes it easier to filter. After filtering the acid with extra water, you heat & evaporate the water, thus reconcentrating the acid. Sulphuric won't evaporate that easy! You'll know the water is out because the acid will start to "smoke", plus check with the original acid volume.

I have plenty of fiberglass insulation, so I use a plug as filter & then run some HCl/Cl thru it & recover the gold from the filters. Some like to use toilet paper.

I hope this helps.

Phil

 

[Amber]

Hi Amber!
The hose would not contain that much acid to make a big "splash".
I use a big syringe, (from a farm feed store), & squirt some water thru the 1/4" clear hose & into ANOTHER container. Keep that water out of the main acid!

Phil

Thanks Phil! I was hoping that was the case that if you let the hose drain for a bit while doing other stuff you could rinse it out pointing the open end into a waste container, or a drain. Then continue to flush the drain. We learned in pesticide training that the best way to dispose of product is to use as directed. So with that philosophy I think it would be correct to rinse drain opener into the drain. Especially the small amount that I'm rinsing out of my siphon hose. I am saving the bulk of it to re-use.

I let the sediment in the main container settle for a day or 2, & then siphon; it makes it easier to filter, but one could just start filtering thru several times until the acid is free of sediment. The acid w/sediment can be slowly added to several times its volume of water, (keep track of how much acid you started with); that makes it easier to filter. After filtering the acid with extra water, you heat & evaporate the water, thus reconcentrating the acid. Sulphuric won't evaporate that easy! You'll know the water is out because the acid will start to "smoke", plus check with the original acid volume.

I have plenty of fiberglass insulation, so I use a plug as filter & then run some HCl/Cl thru it & recover the gold from the filters. Some like to use toilet paper.

I hope this helps.

Phil

OK, now I'm a little confused here. I have not started running a cell yet, so maybe it will be more clear later. I like to visualize everything I can before hand. That's what made me ask about the siphon hose. In my mind, I was standing there with a hose and I didn't know what to do with it. Thanks for answering that question. Your answer gave me another question.

Help me understand what you just outlined. If I have been reading correctly, I will let the black powder settle when I am done running the cell. I siphon off the acid and save for re-use next time I want to set up and process gold plated scrap. The remaining black powder and acid mix is poured into a larger quantity of water, slowly. Then settle, decant (using a filter), and repeat as needed. That will leave me black powder to refine now and a filter paper to add to the collection for later processing. Why do you describe evaporating the water to re-claim the sulfuric acid? Are you saving the small bit that is diluted with the black powder? It can't be but a small percent of the original volume. In my mind it was waste. Or is your process a little different? Are you diluting everything that was in the cell?

 

[Palladium]

What he is talking about is letting the cell settle so all the black powder is on the bottom. Them you try to remove as much acid as you can without disturbing the powder. The acid you just removed is concentrated so it won’t have to be boiled back done like the dilute acid will be. What you can’t remove will be trapped with the black powder. You have to dilute this with several times the volume with water. You can’t pour the concentrated acid through the filter paper or it will eat the filter paper up and cause you a big mess. Once you filter the remaining diluted solution to recover your gold you can now take the diluted solution that came from this and heat it up to drive off the excess H2O2 and it will be re concentrated and ready for reuse in the cell.

 

[philddreamer]

You're welcome Amber!
Don't flush straight down the drain BEFORE filtering, in case any gold that might be in the rinse. Make sure no values are present in your rinse, then dispose.
Ok, I learned that one can let the sediment settle in the acid for a couple of days.
Or in order to speed the process, dilute in 2 or 3 times water, that way the acid is thinner & easier to filter. (I always have something else going, so I don't mind waiting).
After you have filtered the the acid & ALL the gold sediment has been recovered, the diluted acid is heated until the water starts to evaporate. When the water is gone the acid will start to "smoke". BE VERY CAREFULL...
Let the acid cool & store. Don't let sulphuric acid expose to humidity over nite, you'll have to evaporate again. Diluted sulphuric will dissolve copper.
So, if you had 1 litre of sulphuric in you cell, diluted with 3 litres of water for filtering, after filtration, evaporate the 3 litres of water & you have your 1 litre of acid, (-), for the next batch.
The black powder then process thru HCl/Cl & so on.

 

[Amber]

Thanks Paladium and Phil. You cleared up my questions. The system is no loss for both acid and gold. Gold powder unintentionally siphoned off in the top part of the concentrated acid is reused in the cell and will be recovered in the next run. You're doing the same with the diluted acid. A little heat and back to concentrate. Would you consider this step optional?

Thanks Phil for reminding me not to rinse the siphon straight into the drain. It could have picked up powder especially at the end of the siphon. So I'll rinse into a container of water and add that to what I collected and diluted from the cell. Or better yet, I'll rinse it first into the prepared container of water that I'm going to pour the black powder and acid into.

I think I am ready mentally to give it an actual run. I just need to gather a few items including a rubber apron. And I need a weekend that is free. I hope to proceed and post some photos in the show and tell area by the end of September.

Thanks again for helping me understand.

Amber

 

[Geo]

there's no real reason to concentrate and reuse the acid other than the economics and less chemicals in the environment.where i live two liters of drain cleaner is about $15.00 so if i lose 1/3 of my acid due to diluting and filtering at 1 liter per run i would only get 3 batches for $15.00 but by recycling my acid i only add about 1/2 a cup per batch and get to reclaim that at a later date, at that rate i get 8 batches per container.

 

[philddreamer]

Yes, the step its optional. A person makes the decision according to concience, finances & a good "waste handling" practice. Make a habit of the latter, in case some neighbor decides one day to call EPA on you. You show them you have everything well under control.

Before you start your first batch, write every step down so you can follow them & minimize any mistakes, like, ooops I forgot to do this, or that...
I've been there & done that... :roll:
Looking forward to hear good news! 8)

Phil

 

[Amber]

Before you start your first batch, write every step down so you can follow them & minimize any mistakes, like, ooops I forgot to do this, or that...
I've been there & done that... :roll:
Looking forward to hear good news! 8)

Phil

You and I think alike Phil. I do have notes. I visualize. Then I will set up and walk through dry. Once live, I am certain I will still find some where that I will want to improve next time. I'm used to that. I am a designer and always, when a project is done, I would do it different. I made a second copper basket today and it is better than the first.

Thanks again for the encouragement. I am confident of success.

 

[Photobacterium]

Qiuck power supply question:
I am pulling apart 100 24 port hubs.
The power supply that comes with each uses a tower wall plug which
connects to the adapter.
The adapter numbers are
1.0A max 47-63Hz
Output: +5v 2.5A

Would this be enough power to supply a gold cell?

i suggest an old AT power supply. they have an on-off switch attached.

the newer power supplies (ATX) get their on-off through the motherboard.

sources for these power supplies -

http://www.pacificgeek.com/product.asp?ID=22685&C=216&S=1242

$50 + shipping is pricey, but i just wanted to show you what i was talking about.

250 watts is typical for these. They come standard with the older computers.

Someone correct me if these are not adequate for a Cell - I have not done a Cell yet. But I use them like a cheap lab power supply, or in the old days for my computers - for that they work good.

Other sources -

http://www.alltronics.com/

[b]http://www.halted.com/[/b]

Halted is one of my favorite surplus stores, been going there for 20+ years.

 

[dtectr]

This is my 3rd edit. Read on and you will see why. Sorry.
This is in response to GEO's suggestions regarding clean up of the cell. I am forced to use my cellphone and threads are very hard to follow right now. Hope this helps someone.
i like the forced dry to discourage oxidation on the basket.
The toothbrush not so much. H2SO4 attacks organics very vigorously, leaving a goo that unless followed by Incineration creates its own set of problems. If they are still available, a fiberglass brush such as once used by typists or else a stainless one rinsed immediately would be preferable.
IMHO

 

[Geo]

This is my 3rd edit. Read on and you will see why. Sorry.
This is in response to GEO's suggestions regarding clean up of the cell. I am forced to use my cellphone and threads are very hard to follow right now. Hope this helps someone.
i like the forced dry to discourage oxidation on the basket.
The toothbrush not so much. H2SO4 attacks organics very vigorously, leaving a goo that unless followed by Incineration creates its own set of problems. If they are still available, a fiberglass brush such as once used by typists or else a stainless one rinsed immediately would be preferable.
IMHO

im sorry. sometimes i don't explain everything i say well enough. i never meant to imply anyone to use a used toothbrush. i buy the ten pack from family dollar for a buck to do things like that. there should be nothing organic on them. i understand i said old toothbrush and again i apologize as its really a matter of style of speech. im not afraid to say that im as redneck as it gets and my speech reflects that. no matter how well you can write you cant get away from lifelong habits. here we say things like upinunder, I've had people ask me exactly what it means "upinunder a car" "well" i say " you have to lay down and look up in under to see the muffler".

 

[Smack]

This is my 3rd edit. Read on and you will see why. Sorry.
This is in response to GEO's suggestions regarding clean up of the cell. I am forced to use my cellphone and threads are very hard to follow right now. Hope this helps someone.
i like the forced dry to discourage oxidation on the basket.
The toothbrush not so much. H2SO4 attacks organics very vigorously, leaving a goo that unless followed by Incineration creates its own set of problems. If they are still available, a fiberglass brush such as once used by typists or else a stainless one rinsed immediately would be preferable.
IMHO

I get my brush from a auto parts store, it's just like a toothbrush but the bristles will hold up to the chemicals, it's just a small parts cleaning brush.

 

[dtectr]

Geo
Don't apologize, my amigo. As I mentioned, I have been using my cell, so I didn't explain, either - I still consider most plastics as organic, as most cheap-os are petroleum products.
Again not necessarily accurate on my part. Maybe someone with more chemistry know-how can clarify.
Every time I used the toothbrush it was in conjunction with concentrated H2SO4 & it turned to goo immediately. The parts cleaning brush would be more chemical resistant, I imagine.

 

[spooks69]

Two questions about building this cell, and I have book marked this thread because it is absolutely the most informative.

1) has anyone made a solid copper basket like the "Mighty Mite" sold on Ebay? I have one constructed, and I think it needs some "Drain Holes" drilled into the bottom to allow the particles and acid to not pool up inside of the basket. Will this work in your opinions?

2) do you need to use a lead cathode? Can you use Stainless steel? I spent two hours fighting lead this evening, and I'm really more of a "sheet metal" guy...

Thanks!

 

[Harold_V]

Two questions about building this cell, and I have book marked this thread because it is absolutely the most informative.

1) has anyone made a solid copper basket like the "Mighty Mite" sold on Ebay? I have one constructed, and I think it needs some "Drain Holes" drilled into the bottom to allow the particles and acid to not pool up inside of the basket. Will this work in your opinions?

2) do you need to use a lead cathode? Can you use Stainless steel? I spent two hours fighting lead this evening, and I'm really more of a "sheet metal" guy...

Thanks!

The concept of a solid basket has merit. A sulfuric stripping cell works by dissolving gold, not by electron flow from the objects being stripped. The sulfuric acid is converted to persulfuric acid in the proximity of the anode, so as long as it is present, any gold within the proximity should be dissolved. The only real need for open areas is to drain the residual acid when the basket is removed. I would recommend a generous amount of open space, assuming it doesn't cause the loss of the items being stripped.

Harold

 

[spooks69]

Two questions about building this cell, and I have book marked this thread because it is absolutely the most informative.

1) has anyone made a solid copper basket like the "Mighty Mite" sold on Ebay? I have one constructed, and I think it needs some "Drain Holes" drilled into the bottom to allow the particles and acid to not pool up inside of the basket. Will this work in your opinions?

2) do you need to use a lead cathode? Can you use Stainless steel? I spent two hours fighting lead this evening, and I'm really more of a "sheet metal" guy...

Thanks!

The concept of a solid basket has merit. A sulfuric stripping cell works by dissolving gold, not by electron flow from the objects being stripped. The sulfuric acid is converted to persulfuric acid in the proximity of the anode, so as long as it is present, any gold within the proximity should be dissolved. The only real need for open areas is to drain the residual acid when the basket is removed. I would recommend a generous amount of open space, assuming it doesn't cause the loss of the items being stripped.

Harold

Awesome Thanks Harold! Any ideas on stainless or galvanized metal vs lead cathode?

 

[Harold_V]

Awesome Thanks Harold! Any ideas on stainless or galvanized metal vs lead cathode?

I'd be inclined to suggest lead, but if you keep water out of the sulfuric, GSP swears that steel will serve perfectly well. Large stripping cells are made of steel sheet or plate and apparently serve perfectly well. He also suggested that stainless was not a good choice.

The large cell I built (but never put in service) was water cooled and made of stainless. The tank itself was the cathode. Not having operated the cell, I am unable to speak from experience.

Harold