First time electrolyzer de-plating

First time user here, beginner at large!
I purchased from store and Steve basic supply's needed to deplate pins ala:LazerSteve style so to speak.
Am writing some informational notes as I proceeded to deplate some pins.
This setup is using 3cups 96% sulphuric, 2 DC power supplies one providing 12vdc power to the CCPWM circuit and the other provides whatever DC voltage I decide to choose.
First time so set at 12vdc deplating, connected a thermal couple to check temps as I go so start was a cool 51 degree, 12vdc, 60% duty cycle 4khz pulse started at 4.6amp with 110grams pins.
For some reason only 110grams pins fits into the copper liner.
Okay so a bunch of small white hydrogen bubbles were coming off the lead, so I decided to turn down to 9vdc and it brought me to 3.1amps.
Run time 20min and donetemp rose to 55degree. Rinse pins and reset for round 2.

2nd time 112grams pins same setting 9vdc start at 4.8amp and drop to nothing in just about 20minutes then poke around for minute and done temp rose to 68degree.

3rd time 113grams pins same setting 9vdc start at jump to 7.5amp relax 1 minute to 6.5amp and slowly dropping to zero amps in less than 20minutes temp rose to 82degree at finish, but this time there was some float build up in cell. Salt/metal don't know?

So I stopped here cleaned/rinsed covered everything to ask a question about the float build-up that just started.
Does this float start because the acid is starting to get saturated?
Can I still run more pins and not worry about the float?

There was more float right when I stopped and while cleaning I tried to knock it down some.

The floating stuff is probably some of your gold and maybe some copper. Looks nice. A lot of equipment you have hooked up there.
Keep
It
Simple

Don't know what the float is but at some points it has a gold tone and at other points it has a gray tone.
Either way its metallic and has to be dealt with good or bad.
So I ran nearly another 300grams pins for a total of 610grams pins in this batch.
Smaller batches ran much faster.

The only added parts in this system is a CCPWM that I use with hydrogen gas.
This one just happens to be in 2 small enclosures but its really like one part to me, looks like a few wires but its pretty much nothing. 12vdc and a negative wire that will be pulsed thats all.
I like the way this is operating and no where have I seen here anybody speaking of how the amperage works from high to low like I'm seeing.
Also there are no real posted tempuatures, all I see is warm hot and boil and that is hard to relate to when people talk of boil and really mean something else.
Whats that about? Temperature plays an important role because from what I have read at times if temps are too hot it will effect other metals than what you are trying to make a primary reaction on.
This unit turns on and 20 min later there's no current on 110grams pins. I poke around and get a little current jumping and moving for a minute at the most and its done its job.
Funny thing as to why the current goes to zero but I'm thinking it has something to do with this particular CCPWM.
Has anybody posted their current usage on the battery chargers? Whats the current when the batch is done?
Just trying to see if we can relate something here.

Its been a while since I ran my cell.When the current stops dropping it should be done.You don't want to leave it in passed that point to keep the base metals from coming into the solution.I don't remember my meter dropping to zero,I think it dropped to about 1,and you can hear the sound change when the gold is off.Hard to explain,but you will get the hang of it.
You don't want to let it get too hot,so let it cool down between batches.

Jim

I didn't really mean anything bad about yours. It is just a fact that most are going to look at your setup and not understand what you have and get confused by the wireing. A simple positive wire and negative wire from your source is all most setups need.

When your material is finished deplating your load will drop because it has finished the deplating process, your gold will deplate faster than your copper will dissolve till you reach certain conditions. Either your solution has become saturated with water and therefore starts dissolving your copper faster. your solution has been run too long under a load and has heated up and needs a cool down time, a warm solution will dissolve your base metals faster than a cool solution, it also might indicate you are possibly trying to deplate too much material at once in too small of a container.

The power source that I use is a simple old and I mean old Dayton battery charger. 120 AMP max load, 6V Hi/Low, 12V Hi/Low, Boost. The container I did use held about 3/4 of a liter or solution and I ran it on 12V Low with just a hot and ground. It has a built in amp meter and when the load drops I know the material is finished. It will deplate a pentium pro gold top in around 1 min. This container set in another container the held an ice bath. If I remember right around 75 pentiums could be done with a round of solution. Very simple setup.

I like the nature of your expierimental approach.
I would be concerned about the electronic equiptment and corrosion.
I am having trouble figuring out what ccpwm stands for?
are you making this a little more complicated than it is?

I see here at the forum most electrical setups if not all are straight DC voltage.
CCPWM stands for Current Controlled Pulse Width Modulation.

Lets start with Pulse Width Modulation , instead of a straight line DC voltage now I have a line with breaks to zero volts. _|_|_|_|_| on/off and in this case I left the on/off frequency at 4000 times per second. What this does right off the start is allow you to use less current because the current value you see is now an average of the on/off period.
Now it has a a duty cycle which means how long will it be on. When I say duty is 60% it is on 60% of that pulse. Straight DC is 100% duty no pulse.
Current Control is the amperage setting I can choose or set, for example if I want my highest amperage to be 6amps and I put my pins in and in many cases they jump to 7-8 amp at start what the current control would do is not allow it to pass over 6 amps by changing the pulse duty cycle so instead of 60% on time it would allow whatever on time it needs not to pass 6amps of current which means the duty on time could easily be 20-30% of the time.

This control can do many interesting things, thats why I'm using it to discover its use in the electrolytic cell configuration.
You have heard of people rejuvinating dead battery's before haven't you? Thats done with a pulsed DC. The effect is pulsing off (dropping off) the build-up that happens on the electrodes to expose fresh surface area.

Pulsing DC voltage and the ability to change the voltage hi/low with the control of current threshold and duty cycle will have effect on the efficiency of the process.
Thats what I see.

Here is the preliminary take on this first experience of using a cell set-up.
My low temp was 51 degree and thats unusual but its winter time so its nice having a cool temp to start with.
You speak of warm or hot which is a wide variation of actual temperature.
Whats warm? Is luke warm 70 degree's? Then warm is 75 to over 85 degree's?. Hot is just starting somewhere around 90 degree's, too hot to touch starts at 125 well you can touch it but at this temp there is slight uncomfort in the feeling.

With the CCPWM the temp is now slightly controllable and won't run away as in a straight DC voltage.
My highest temperature was 82 degree's, I bet some of you have started your equipment in excess of 82 degree's because in Southern California there are many days/months that 82 and over is constant the the ambient temp is 82 or higher.
Well if my thinking is correct 82 degree's falls somewhere in the warm zone, its not hot. Warm is good is it not?
Do you think I pulled copper into my solution at 82degree's?
I think it will take over 95-100 degree's temp on the acid to start to eat into and dissolve the copper, but I am not at that experience level to acually state that temp zone. Thats a guess and I would like to know more about temps.
What I want to find out is what is the acid temp threshold that the copper will start to dissolve into the solution? Simple is there an answer? Not hot or whatever but what is the actual stated temperature?

Here are some of your problems with changing values here at this forum.
A measurement of value done by one person is not the same as the measurement done by another. This is variation in equipment as well as technique and as well as stating hot, warm and cold.
Percentage of acid and dilution is variable.
DC chargers are not all the same, actually some of them most likely do pulse, but with the different chargers the voltages can be from 13.5 and up to many more volts.

So what I'm saying is there could be a better understanding for me at least if I control the temperatures and currents and voltages then I could make better assumptions of my yields in the process I am using and not make mistakes of for example allowing copper to get into solution because of a temperature variable.

Maybe with a CCPWM some new method will arrise, someone has to experiment don't they?

You are aware that when the harger is running it is taking your gold for a short period of time and dissolving it in the acid and as your gold migrates away from your material is becomes a solid material again. Well if your flow of electricity is only running 60% of the time then you are loosing 40% of production over that time frame the system is running. And if you are trying to control the temp of your solution and it chngeas to only running 30% ofthe time you are loosing 70% of your production. If you want to control your temp simply leran what materila you are running and lower the voltage to accomidate a slower process and not build up as much heat.

Thanks for the explanation of CCPWM, I am very familiar with pulse width modulation as I have built several electronic circuits using it, and have worked on many control circuits that used it have also used pulsed width modulated current in electrolysis experiments (unrelated to refining metals). in electrolysis where you are not trying to plate an anode but to get metal into solution it works well, but my experience is limited here. I just have never heard the abbreviation of CCPWM.

Pulsing may have benefits in your cell, but may also have draw backs and create some problems?
I do not use this cell, but my understanding is that it is generating per sulfuric Anion, which allows it to dissolve the gold, my guess is straight flat line DC current would keep that ION flowing towards the anode (gold pins you are deplating), and keep it in that vicinity.
Gold will not dissolve in sulfuric acid, but will from the per sulfuric, this per sulfuric bubbling at anode dissolves the gold but as soon as these gold Cations move a short distance from the anode and inter the sulfuric environment (on their way towards the Cathode, they fall out of solution, my concern using pulsing current is you only have per sulfuric a short period of the duty cycle and with a fast pulsing relatively high frequency maybe your gold will plate back to anode or not leave as easily.

I do not know, but looks like you will find out, I am interested in your finding on this.
I would get my equipment in a separate room (environment) from the cell or where I refined, example my power supply would be inside the shed and cell outside, and just wires to connect the two.

Butcher so you see the only difference from pwm and ccpwm is the current control limiting part.

I'm very curious on this set-up I decided to try too!
The material deplated nicely and I'm thinking there is no copper in it.
The cell contents are settling, figure this should have its 24 hour period before I siphon it off and filter.
The clean up containers both have material settling right away in them from rinse so it appears that it should be working properly.

I have much study and test to do to really learn about these processes.

Also have an idea on vacuum cleaner vapor processing hood.
Maybe you have heard of the drywall filter container used when sanding drywall to totally reduce powder from being airborne.
It works like this: vacuum cleaner on end pulling air through a sealed bucket filled with water.
What happens is the water should catch/filter the airborne particles and in the case of drywall it does.
Now if we modify the piece in the bucket to disperse the water into small streams instead or the large stream then it will wash/filter any contaminants.
This is the next thing I want try.

Look up scrubbers; it will give you some ideas, sounds like what you are talking about.
if you wanted to determine about how much copper your solution has you could take a small measured sample, dilute sample, cement any copper and dry and weigh. (just diluting may also give clue by color of solution.
concentrated H2SO4 does not attack copper easily in this type of cell, run with straight DC, and practically no water in acid and as gold is removed the way I understand the amperage drops off.
As I stated I have not used this type of cell, Laser Steve has written about it and it has been discussed by many more informed people than I.

Yes thats it home made scrubber. A vacuum scrubber in my case.

I'm not experienced yet but by the looks of the material that was unplated it appears perfectly sound less the gold plating.
Will inspect it and try to siphon it off later this evening.
I'm curious to see what 610 grams of board edge pins, DB sockets, cable connectors etc... will produce in the end.

hopefully some pretty heavy yellow metal.

Well its still coming along slowly, posting my details of this begining stage of experience.

Got to pouring off not siphoning the black acid bath.
On the bottom was the mud which was saved into another container and has a primary wash.
Looking at the acid from the bath thinking there is still much much black in it and it has not settled enough, so last night I heated it to warm and let it set overnight. Thinking that because of my cold garage in the 40's the sulphuric is so thick it won't allow the powder to drop. This did work well as I poured off one more time there was plenty black settled again in the bottom and the poured off acid although still plenty dark I was able to see through the edge from the top to the side, a nice deep amber/brown color.
I will still use this remainder to run more pins before a final filter.

Speaking of filter, wow! What a job cleaning stuff. I guess a guy can filter forever. Cleaning, lightly juggling the pins gave me a small amount of good black powder. Rinsing the copper and the lead gave more black powder, didn't want to brush the lead or copper (just rinse). After a quick wash down of the filter catchings into my main container, then saved all filter paper and residuals in a bucket.
Playing with waste water adjusting PH.

I was a little worried what Barron said about ionic exchange but the pulsing seemed to work alright.
Still having more material to work with I'll run 500grams or so with a straight 12VDC and take the informational data of the 2 runs and see if I have differences in my processing.

Things I have noticed about the acid:
While pulsing no smell or vapor is being produced. Will see if there is any difference using straight 12vdc.
While testing small acid samples and putting them in water and while cleaning the sulphuric acid for the first instant there is a brief vapor at the point its mixed with water.

Sorry about that, Iwasn't trying yo imply it wouldn't work. What you are doing is fine if it makes you comfortable. It is fine from a hobbiest stand of view. But if you were in a production setup where time is money it might cause you to devote more time to processing the material. Time can't be made up once it is gone it is gone....

This is interesting. Adam, I applaud your efforts to be precise. I'm a retired electronic engineer and I recognized PWM, but needed an explaination for the CC part. I have yet to try deplating gold in concentrated sulpheric. I have plenty of electronic equipment and know how to design circuits once I have the need to do so. Some current limiting is pretty much necessary for the standpoints of preventing damage to the power supply and possibly the operator, but is it desirable for the deplating process? One can always reduce the peak current by running smaller batches. Is that better than using more currrent limiting with larger batches? Is current limiting done by reducing voltage better than by use of PWM?

I'm staying tuned to find out.

FrugalEE

keep up the good work, it is interesting.

This appears questionable.
From a first timer is this auric chloride okay? Meaning do I see a faint tint of green in there?
Also the salts in the filter. What are they, or what could they be.
As you see the processing was pins, taken from 1970's test equipment up through 1990's computers.

As far as the CCPWM my take on it was I can run at higher voltages above the norm and keep the heating down to a minimum.
Once a current is chosen from past experience then set as a limit it will not exceed the setting which again keeps the heat down and the voltage can be high.
The controlled current will automatically adjust the duty cycle to maintain its peak setting.
From my small experience it works okay at the setting I used.
In order to gain experienced knowledge now I have to run a batch at straight DC like a charger and then another batch at excess voltage and still one more batch at very low voltage and take the data of deplate time, acid temperature and current.

Now I'm concerned whether this auric chloride appears visually correct.
I appreciate your reply's.

FrugalEE as you see at this point the data has to be collected by doing the several batch runs at the different settings. Once the information is acquired we'll be able to tell if a CCPWM is a worthy tool or not.

Barren your replys are noted, and they are all good. I'm making it a point to find out if this method can become usefull in an overall process. As you can see only one setting was used to run six small batches. The 5th batch was approximately 90grams and took 15min verses the 20 min at 110-114grams and the 6th batch took just under 10minutes at approximately 60 grams of these pins.
Pretty much we now have a single setting test batch of data, now I have something to measure against on the next run.
Also need to measure the yield from this batch of pins.

some copper in solution (not terrible), looks like maybe solder lead in filter. also looks like a hint of copper sulfate or carbonate in filter?

The gray powder is normal, not sure what it is, but it's very common.

I have a long reply prepared to this thread, but it's on another computer. I'll post it later.

Steve