Electrochemistry Ambitious Project!

[publius]

I am planning to set up a series of electrowinning cells using 12 volt batteries as the source of power. I would like to power up to six, one liter silver (nitrate) cells and three, two liter copper (sulfate) cells. I intend to use LaserSteve’s graphite cathode is both cells. The silver cells will be the classic Balbach-Thum cell whereas the copper cells are to be Moebius cells. The copper cells are intended to recover gold and the like that comes from stripping copper from AP and A/CL solutions et cetra by cementation using iron..

I know that 12 volts is too much for the silver cells but if placed in series will they not offer enough resistance to lower the voltage to about 2 to 3 volts?

Would I be pushing the voltage or even the amperage on the copper cells if I ran them in parallel?

So many questions, so little experience...

Is there any good book(s) or other resources I can find before I scale up?

Thanks in advance.

Robert Jeffery, CWI

 

[element47]

You're on the right track as far as reducing the voltage, but car batteries can supply massive current, so if you get a short, you could get some issues. Fire, smoke, sparks. I'd definitely reco a fuse somewhere in the circuit...perhaps 10 amps. How are you going to charge the batteries? And, would not whatever charger you plan to use be a more convenient (and cheaper) power supply? Kadriver had good results when he took either the 5 volt or the 3.3 volt output from a PC power supply (all of which require an external resistor to work outside of a PC) and ran 2 cells in series. So was running either 2.5 volts or 1.65 volts per cell as his voltage level. Search for some of his posts. He has great pix, too. You could also PM him to get his YouTube handle and watch some of his YouTube videos, .

 

[lazersteve]

Add a variac in line with your manual battery chargers AC power supply cord and you can control the output voltage of the charger for use with two cells in series. Make sure the variac is rated to handle the amps the battery charger needs.

Steve

 

[Barren Realms 007]

Add a variac in line with your manual battery chargers AC power supply cord and you can control the output voltage of the charger for use with two cells in series. Make sure the variac is rated to handle the amps the battery charger needs.

Steve

Steve,

Would it not be better to install the variac between the batteries and the cell's with the proper meters for measuring the voltage and amperage. This would leave the charger with constant voltage without the possability of damaging it if you ran the voltage real low on it. If you lower the voltage to the charger it will raise the amerage on the charger because the charger is still trying to bring the batteries up to full charge with the same power load. But if you install them between the cell's and the batteries you have the reseve power source of the batteries with less posability of damge to the charger.

 

[lazersteve]

Barren,

With manual battery chargers there is only a transformer and a rectifier inside (aside from the ammeter, thermal cutoff, and wiring). For this reason there is no feedback or regulation to worry about in automatic style chargers.

Steve

 

[publius]

Steve,

Would this work? http://www.amazon.com/Variac-Variab...C6HU/ref=sr_1_9?ie=UTF8&qid=1335991732&sr=8-9

 

[qst42know]

Variacs reduce AC voltage only. This must be accomplished before the rectifier.

With a Variac and a rectifier no battery charger would be necessary.

 

[butcher]

Yes that is a variac like Laser Steve was discussing, they can vary the AC voltage lower and even higher than alternating current from your wall outlet, It is a large coil transformer, with a movable dial (brush output) variable transformer (step up or step down), and this way you control the AC voltage to your battery charger (or rectified direct current power supply) which will allow you lower its DC output voltage to most any desirable range, I have an old one similar to that one used for working on electronic circuits, I also have an old fluorescent light dimmer basically the same thing.

The variac and a battery charger (sized large enough for your cell) along with a large variable resistor or the proper light bulb in series with your refining cell would make a very good power supply.

The variac will allow adjustable voltage output (installed in AC circuit before the battery charger, or AC to DC power supply).

The large varible resistor will limit current to desired value, (installed after dc supply in series with your cell)

The series light bulb can act as current regulator and short circuit protection (installed after DC power supply in series with cell).

 

[Barren Realms 007]

Steve and butcher you are both correct and I agree with your statements.

Here is my concern in this setup and the reason I made the post.

publius are all the batteries hooked together with one battery charger keeping them all charged or are you going to have a seperate battery for each cell or series of cells and move the charger from battery to battery to recharge one at a time.

The way I took the original post is that all the batteries are hooked together with one charger keeping them charged constantly and that was why I raised the question I did.

 

[butcher]

We were talking about running the cell off of the power supply directly without using batteries.

With battery’s it would be a little more difficult to control voltage to the cells, of course you can run several cells in series, but their resistance will vary somewhat and you will still need to control the voltage (the current would be the same for all the cells if run in series) you could use a voltage divider series in circuit like large variable resistors, to burn up some of the voltage, but this would be a waste of power, and unnecessary.

You would also have to worry about expense and upkeep of the battery bank.

 

[publius]

Barren,

The plan is to take one battery (12 volt, deep cycle) and connect it to 6, one liter silver cells connected in parallel. Charging the battery was to be done by swapping batteries out and charging the spent battery using a solar charger.This was to be accomplished using a simple switch.

The battery charger and variac were suggested by others as an alternative method to charge the battery or run the cells in place of the battery. Other suggestion for limiting the voltage/current were also offered.

At this point I am still in the feasibility/design phase. So any suggestions and comments are welcomed.

 

[Barren Realms 007]

butcher,

That was where the thread progressed to and I agree with the suggestions. I just wanted to have a clear picture of what publius was building so there would be no confusion in what he was trying to acomplish.

 

[lazersteve]

Barren,

I missed the part where he mentioned the use of battery power for the cell(s). Looking at the cost of what he's using I feel he would be better off using the money to buy an AC powered (if he has AC at his location) manual battery charger and a variac.

If he does not have AC at his location, then his DC source is easy enough to regulate down to the required voltage with an LT1038 three terminal adjustable voltage regulator.

Here's the datasheet for the regulator:

LT1038 Regulator Datasheet

A few external components and your regulator can be set (or adjusted) to any voltage between 1.2V - 32V DC at 10A continuous current load. For higher amperage requirements check page 6 of the above datasheet for paralleling more than one LT1038 component.

Steve

 

[butcher]

Steve,
I have worked on, and built many power supplies, and many voltage and current regulator circuits, I have also worked on the old style voltage regulators for cars and tractors.

But I never thought of using these semiconductor regulator circuits in a DC battery operated circuit, (I have always used resistors or other components to form voltage divider or current limiters in the circuit) the use of the semiconductor voltage regulator or current limiter make sense, because we always rectify the AC to DC before the regulator, and the modern vehicles use these also (but they are ran from rectified AC from the alternator).

Thanks for opening my eyes to something so simple I never say it or thought of it.

 

[Photobacterium]

If he does not have AC at his location, then his DC source is easy enough to regulate down to the required voltage with an LT1038 three terminal adjustable voltage regulator.

Here's the datasheet for the regulator:

LT1038 Regulator Datasheet

A few external components and your regulator can be set (or adjusted) to any voltage between 1.2V - 32V DC at 10A continuous current load. For higher amperage requirements check page 6 of the above datasheet for paralleling more than one LT1038 component.

Steve

for those of us who recycle computer parts - and are wondering where to get voltage regulators - computer motherboards usually have some, and so do some video cards - and so do the power supplies themselves.

same for a lot of other e-scrap - e.g. power supply for a printer. so if you need a regulator that can handle some medium high current, these are some sources -

1/ E-Scrap bin
2/ Call the manufacturer, tell them you're an engineer (probably not too far from the truth), ask for a free sample. They can be surprisingly helpful.
3/ E-tailers like Alltronics, Mouser, & Halted.


Linear Technologies is one of the biggest names in regulators. National Semiconductor used to be.