Copper recovery from copper sulphate solution

[tawanda]

Your amperage is to be determined by the cathode area (size) or the size of how many cathodes are involved in the cell... larger cells run at higher amperages.

Depending on the metal being oxidized and reduced the range of amperage will vary.
You can look up amperage per square foot, and convert to inch for that metal or find or convert in metric...

a slight excess of amperage is ok.

Too many amps on a small cell may not only see it splitting the water but may become uncontrollably reactive,

I would not put my welder on a setting of 260 Amp on a small silver cell with a 3-square-inch cathode. I would probably not only see water bubbling as it split, but I may have a heck of an acid volcano with hydrogen gas and arcing ...Hmm could get nasty, this may or may not be a slight exaggeration of the possible danger or problem but you get the idea, we do not wish to weld the anode to the cathode or burn off the electrolyte.

several other conditions pH which can change in the cell as gases evolve or water is split normally the anode compartment gets acidic (hydrogen+ ion) and the cathode becomes more caustic alkaline or basic (OH- ions),

The temperature of the electrolyte, which also as almost everything can be related to the cell and how it is going to operate, more resistance (think electrolyte resistance ions in solution ) and the external resistance of the external circuit, bad connections, too small wire carrying current to and from electrodes, can waste current, build heat and cause grief, higher resistance, and higher current also mean you will have a higher wattage produced (we are not making an electric bathroom heater out of our cell, unnecessary wattage of wasted power...

Even the metals involved play a role, how reactive or how unreactive the metal or its ions are, where their place in the series, how they react in the cell (with each other at times), the metal ions are soluble or insoluble are they depleting the electrolyte (think insoluble lead sulfate taking the sulfate ions with it, or silver taking chloride ions from electrolyte with it out of the equation of the cell to deposit it in the mud or slimes...

Several factors are involved some more than I can't think of right now too tired of typing blindly with one finger...

Thank you, I will need to take some time to assimilate all this. I will definitely keep you updated on my progress.
Out of interest, in copper electrowinning, would it be possible to have a vertical, hollow, cylindrical anode, maybe 15cm diameter, with many little cathode rods dropping down the centre. This way I can create a system where the copper sulphate solution flows slowly upwards through the 1m high anode comes out through the top and drops to the bottom of a similar cylinder at a lower level so the electrolyte rises up the cylinder on its own. Maybe have a series of 10 such cylinders thus increasing the surface area. Idea is to keep it in constant motion shifting any inert zon

I have seen these mixers made from industrial vent fans. Laid on their side with a mixing blade replacing the fan blade. These were used in 50 gallon drums and used flotation to work the materials/ores into the next barrel. I have looked most of the day but cannot find any of the old pictures or videos I had saved. I will keep looking as it has been a few years since I have looked at them.

thanks. I still cant get the stripping process. Do I mix my copper solvent extraction concentrate with sulphuric acid then put it in the electrowinning cell. If so whats the mix ration . Im try to get literature on how they did it in the beginning before all this new technology way employed

 

[butcher]

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Tawanda, when I have questions or doubts I normally work them out, mentally along with more research understanding principles ( at least a little more than the basics) understanding how and why it works before making a plan or acting upon a notion or meaning to get something going,

Forgive me I am having a hard time picturing what your asking, it sounds something like what they use to use to recover silver =from x-ray film where electrolytes flowed through the system recovering a depositing silver cementing with steel wool before dumping the spent solutions down the drain in cast iron sewer lines on their way to the public sewer system to be treated and then dumped back into the river along with everything else the town flushed for the next town down river to pump out and treat to fill that town drinking water faucets with.

I wonder how many times the same water or sewage is treated by each town before it gets to the towns on the lower river.
safety and understanding how to treat waste and deal with the dangers involved should be on first order to research, building a small cell and running it is no big deal and you do not need all of the math, although it and the understanding goes a long way in progress or understanding what goes on sometimes invisible to you, it also helps you to understand and fix any problem or roadblock that pops up like a mole of electrons from some hole in yer garden.

if your idea is doing this industrially or on a large scale I would look into the more conventional design of the cell and the powerhouse workings...

The electrolyte normally stirs or mixes itself (more so if the cell is not salt bridged or has multiple compartments) as the Cation metal + ions migrate to the cathode(-) to be reduced (like copper ions), and the negative Anions - ions (think salt of acid) (like sulfate SO4 ions) beating their way to the anode to give the oxidized copper a pal to play in the electrolyte solution with.
I normally do not find stirring the solution necessary in a small cell.

Although for industrial-size cells that may be different, I do not know never worked around one, I would think they may possibly move electrolytes for cooling or for filtering or adding chemicals, etc again I do not have a clue. the solution somewhat for cooling???

If the cell has an impurity settled out of the solution as insoluble materials, metal flakes, oxides, or salts and not bagged I wouldn't want them to be moving around or anywhere near my cathode, I say let the ole dog lay.

 

[Shark]

if your idea is doing this industrially or on a large scale I would look into the more conventional design of the cell and the powerhouse workings...

I agree 100%.
Stick with the proven methods before venturing into the unknown. Scaling down of known methods is often easier than scaling up uncertain methods.

 

[tawanda]

Definitely understanding the workings of the system on a molecular level helps. I see the ion migration pattern and why theres little to no need to agitate. Oh, do not despair the system im working on will be enclosed to minimise envitonmental contamination.
Many thanks for your feedback

 

[tawanda]

I agree 100%.
Stick with the proven methods before venturing into the unknown. Scaling down of known methods is often easier than scaling up uncertain methods.

I shall do likewise and definitely get back to you with the results

 

[butcher]

Yes, the system may be enclosed but closed.

Then again that is no reason to believe or be lofty that there will not be any toxic or dangerous waste, and or dangers involved, safety procedures should not be overlooked, disregarded, or not looked into...

Anything we do around here, you should look into the best safety practices of our day.

What was considered safe or legal, and normal practice of how things were done yesterday, killed several of my coworkers in some horrible accidents and a terrible way to die.

My body has been suffering throughout my life from accidents, and my health is depleting fast, in my supposed to be prime years, from working with the metals, rocks, and chemicals, I have worked with throughout my working carrier, you name it years of breathing silica, asbestos and a slew of other toxic fumes and chemicals or salts take its toll on your lungs ability to breath, your eyesight, your organs basically just dying with a slow death suffering the shortened life.

Even back then, we knew there were risks involved with the different work we did.
Like if you are climbing on and erecting a 1,000-television tower into the sky.
We understood there was a risk of falling or being knocked off on that 28-degree day,

Stacking and bolting tons of steel, without being tied to anything half the time you were up there, with the winches moving those tons of iron on cables above your head.

Being run by a man you spent the prior night getting plastered with, at the bar till it closed several hours ago.

Knowing he has your life in his hand, also knowing if his hand or mind slips on safety---well you are just dead. That was a chance we knowingly took daily.


With several tons of iron under the control of the winchman on the ground, who may not be able to see you, or see if you wave your arm in a critical moment to tell him to stop, we did not have radios or cell phones to communicate back then, it was normal practice and considered as safe as we needed to practice.


Or years of rebuilding boilers and working with steam lines breathing tons of silica and asbestos used in refractory and insulation, or tonnes of other work where there are always dangers or hazards large and small.

The more you know or understand these dangers the more you can minimize them, those dangers or hazards lurking that you may not see are the ones that kill or maim you for life.

Sure a small electrolytically operated cell can be run by a ten-year-old child safely if he was taught the dangers and practiced safety.
Otherwise, you may just walk into a scene to find that 10-year-old dead on the floor, from electrical shock, where the cell leaked out or spilled its electrolyte onto the floor he was standing on, with the electrical extension cord and no ground fault circuit interrupting outlet he was getting his power from, to run his small DC power supply and his little "safely contained" copper cell...

Study, I say it again do your research.
Be aware, not flighty, it is what you do not know that is a killing potential, or will maim you for life, or damage your child's environment so he is harmed by unseen dangers. As always, the devil is in details we need to educate ourselves and constantly be aware of.

 

[stoneware]

I'm currently adding another hobby which will be using copper electrolyte with 30 liter tank.

After researching 6 volt 300/500 amp power supply's soon realized the cost is beyond my budget,

Instead I'll be using a deep cycle lead acid battery with a home made variable resistor made from ni-chrome wire. This type of resistor AKA load bank often used to test the output and stability of a generator.

For a large stripping cell you could use a 220 volt DC welder wired to 110 volts with a 2;1 step down transformer which would further reduce the input current from 110 volts down to 55 volts AC

With the DC current connected to a home made resistor you could now control the amperage.

On a cell with a large surface area, it's generally covered with ping pong balls to prevent evaporation. For optimum performance the electrolyte must me agitated and heated.

 

[GoIdman]

Just for fun or to fry the brains of those who are trying to follow this math exercise in electrochemical reactions/

Silver (Ag) atomic weight ( from periodic charts) is 107.87 grams per mole of silver

Silver electrode reduction potential of E⁰+0.80volts

Ag+ + e- --> Ag (s)

From the equation we see we need one faraday (e-) to oxidize and deposit 107.87 grams of silver metal (mole of silver) from a silver nitrate solution electrolyte

1 amp X 1 second = 1 coulomb
96485.3383 coulombs = 1 faraday
1 faraday per mole

Silver atomic weight (108 g/mol ) / (96485.3383 coulombs{one faraday}) = 0.0011193 grams of silver deposited per coulomb

Each electron carries an electrical charge of 1.6021x10^-19 coulombs

one mole of electrons 6.022 X 10²³ (Avogadro's constant)
so
6.022x10²³ (mole electrons) X 1.60x10^-19 charge on those electrons = 96485 coulombs (one faraday) able to move a mole of electrons of metal from the anode as ions to deposit at the cathode cathode


algebra equation I am taking on

coulombs / amp = seconds of time
couloumbs / seconds = amps
amps X seconds = coulombs

At this time in the morning when i`m reading this....results... ERROR 404 )

 

[Martijn]

I'm currently adding another hobby which will be using copper electrolyte with 30 liter tank.

After researching 6 volt 300/500 amp power supply's soon realized the cost is beyond my budget,

Instead I'll be using a deep cycle lead acid battery with a home made variable resistor made from ni-chrome wire. This type of resistor AKA load bank often used to test the output and stability of a generator.

For a large stripping cell you could use a 220 volt DC welder wired to 110 volts with a 2;1 step down transformer which would further reduce the input current from 110 volts down to 55 volts AC

With the DC current connected to a home made resistor you could now control the amperage.

On a cell with a large surface area, it's generally covered with ping pong balls to prevent evaporation. For optimum performance the electrolyte must me agitated and heated.

View attachment 54254

This a very wastefull and old way of controlling voltage and it will change as the cells resistance changes during operation, changing the division of voltage over the two loads in series, your cell and the resistor bank, changing the current.
How much current are you planning on running through the cell?
The resistor converts the power in heat that is lost.

 

[stoneware]

This a very wastefull and old way of controlling voltage and it will change as the cells resistance changes during operation, changing the division of voltage over the two loads in series, your cell and the resistor bank, changing the current.
How much current are you planning on running through the cell?
The resistor converts the power in heat that is lost.

Amperage will depend on how much surface area is being plated, yes the wire resister is old school but I'm assured of ripple free current.

I have an older DC welder that I could use but have no guarantee that the power output would be a clean ripple free source which for plating an object is important.

As for the op's project this would not matter in a stripping cell.