Sciencemadness Discussion Board

Used batteries

NEMO-Chemistry - 27-7-2016 at 04:54

From reading on here i am away that mostly discharged Zinc alkali D Cells are no longer Manganese Dioxide, i cant find the thread and cant remember what the Manganese dioxide changes into once the battery has discharged.

So what is the major Manganese component left after a battery is used, and can it be turned into a different product by mixing with something like HCl or H2SO4 (sorry i cant do sub and super script yet).

I would like to have a go at making some manganese salts as i have taken a load apart for the carbon rods. I know its messy but thats ok.

MrHomeScientist - 27-7-2016 at 05:47

I doubt the manganese is affected; it's just an electrolyte. The anode and cathode are the carbon rod and the zinc casing, so if anything the zinc would corrode. If you can find that thread I'd be interested to read it.

Also just in case you aren't aware, the black crud inside those batteries isn't entirely MnO<sub>2</sub> - there's lots of graphite mixed in and it's a pain to separate and purify. Nurdrage has a good video on that process.

NEMO-Chemistry - 27-7-2016 at 08:56

Quote: Originally posted by MrHomeScientist  
I doubt the manganese is affected; it's just an electrolyte. The anode and cathode are the carbon rod and the zinc casing, so if anything the zinc would corrode. If you can find that thread I'd be interested to read it.

Also just in case you aren't aware, the black crud inside those batteries isn't entirely MnO<sub>2</sub> - there's lots of graphite mixed in and it's a pain to separate and purify. Nurdrage has a good video on that process.


Thanks for the info.

The zinc is mostly gone, i will keep trying to find the thread! But from memory i think it was Blogfast that mentioned the Manganese wasnt Dioxide anymore, but i cant remember.

I was aware some the gunk was graphite and i have now watched the NurdRage vid.

Messy job but its fun anyway, the only bad part is when the coffee filter paper splits and you get it down your trousers :S

wg48 - 27-7-2016 at 10:16

Quote: Originally posted by MrHomeScientist  
I doubt the manganese is affected; it's just an electrolyte. The anode and cathode are the carbon rod and the zinc casing, so if anything the zinc would corrode. If you can find that thread I'd be interested to read it.

Also just in case you aren't aware, the black crud inside those batteries isn't entirely MnO<sub>2</sub> - there's lots of graphite mixed in and it's a pain to separate and purify. Nurdrage has a good video on that process.


The manganese dioxide is used as a depolarizer in a dry cell. ie an oxidizer. In a used battery part or all of the depolarizer is reduced so part or all of the manganese dioxide is reduced to a lower oxide.

MrHomeScientist - 27-7-2016 at 11:25

Huh, that's interesting. I didn't know about depolarizers. I did a little research and the depolarizer's function is to inhibit hydrogen production, which interferes with battery performance and could possibly build pressure inside the cell.

I found this site that lists the relevant reactions in a dry cell:


dry cell.jpg - 103kB

[Edited on 7-27-2016 by MrHomeScientist]

NEMO-Chemistry - 27-7-2016 at 12:09

Quote: Originally posted by MrHomeScientist  
Huh, that's interesting. I didn't know about depolarizers. I did a little research and the depolarizer's function is to inhibit hydrogen production, which interferes with battery performance and could possibly build pressure inside the cell.

I found this site that lists the relevant reactions in a dry cell:
Now thats really useful!

So if i have this right i can add say HCl and get Manganese Chloride? From there i can get other compounds.

Great site find, interesting info on stopping hydrogen. Also I noticed Ammonium Ions :D which makes me wonder........ :D

I will let you know how it goes lol. I need to start taking more pics! I dont have much room and seem to end up with the camera being left in the wrong place at the wrong time!

I am not sure how so many get great pics during experiments, i seem to be running about like a headless chicken trying to prevent things boiling over, frothing too much or running away!

By the time it enters my head to take a pic i am in cleaning mode and its all over!

I do have a gadget for recording notes, way easier to talk at ones of those small recorders and write it up later.

I have the double glazed panels for a fume hood, i have a pretty good blower and maybe even a sink.

I am now on the hunt for a lab tap that will take a vacuum aspirator, I have a vac pump but for some things i would probably prefer prefer a water powered one.

Oh and tiles! I am hunting cheap white tiles. Scored a dozen reasonable size CPU aluminium heat sinks free, so i also have a good source now for aluminium compounds.

I am aware foil is normally used but these were free :D.

I was also told today by the guy who owns the Chinese restaurant in town, that the beach i get my shells from has the seaweed used for agar all over it.

As a bonus i know it also has the one for alginate as well. Which leaves more cash for glassware!

I have been given an collection of hydrometers of different densities.



[Edited on 7-27-2016 by MrHomeScientist]

MrHomeScientist - 27-7-2016 at 12:24

What's wrong with ammonium ions? Ammonium is the ion, ammonia is the gas.

Maybe it comes with experience, but if I see something cool going on in a reaction I usually have plenty of time to step back and snap a quick photo. Most reactions don't need to be constantly monitored; maybe you're heating reactions too strongly, or mixing reagents at too high concentration? Good luck with your experimenting!

Finally, just adding HCl to MnO<sub>2</sub> won't go very well. This just produces a fair amount of chlorine gas, and not much ends up dissolving. Again, see Nurdrage's video on purifying battery paste. Here's a link: https://www.youtube.com/watch?v=2gXByJkg0iY
It's more complicated than you might expect.

NEMO-Chemistry - 27-7-2016 at 13:00

Quote: Originally posted by MrHomeScientist  
What's wrong with ammonium ions? Ammonium is the ion, ammonia is the gas.

Maybe it comes with experience, but if I see something cool going on in a reaction I usually have plenty of time to step back and snap a quick photo. Most reactions don't need to be constantly monitored; maybe you're heating reactions too strongly, or mixing reagents at too high concentration? Good luck with your experimenting!

Finally, just adding HCl to MnO<sub>2</sub> won't go very well. This just produces a fair amount of chlorine gas, and not much ends up dissolving. Again, see Nurdrage's video on purifying battery paste. Here's a link: https://www.youtube.com/watch?v=2gXByJkg0iY
It's more complicated than you might expect.


Sorry my mistake, i did get confused with the manganese, i saw the video and then got things a bit mixed up.

The ammonium ion made me wonder if i could get ammonia solution from it somehow, might not be worth it but strong ammonia is not easy OTC around here, ordering it online is a PITA with shipping costs and nothing learned buying it.

The trouble with the Nurdrage videos is you start watching them then want to copy them!

Yes i expect i am using too much and heating too strong, i also tend to watch reactions like a hawk in case i miss something interesting.

I might get more time now i dont also have to try and write neatly as well! The recorder has made note taking much better. No rushed scrawled notes.

I just leave the recorder going and describe what i see and the readings etc, then write up after i have cleaned up. Ok mostly cleaned up as i seem to have a pile of glass to wash!

I will make a big effort on the next batch of experiments and take pics with proper write ups and measurements taken.

Its getting easier now i dont seem to be in a complete panic most of the time, i have larger glassware now so i tend to use smaller amounts in larger glass! Far fewer froth overs etc, followed by frantic attempts to save the hotplate from destruction lol.

blogfast25 - 27-7-2016 at 13:21

Quote: Originally posted by NEMO-Chemistry  

The zinc is mostly gone, i will keep trying to find the thread! But from memory i think it was Blogfast that mentioned the Manganese wasnt Dioxide anymore, but i cant remember.



Nope. What I said was that battery electrolyte contains at least 30 % graphite (non-alkaline batteries). That composition, overall, will have changed little over time.

Don't characterise battery electrolyte as 'MnO2', when in reality it's a complex mixture: MnOx, graphite, ZnCl2, even NH4Cl and iron oxides have been found.

And in fully spent batteries the Mn will be predominantly present as Mn(+3) because:

2 Mn(+4) + Zn(0) === > 2 Mn(+3) + Zn(+2)

... is what drives the EMF of the battery.

Please don't misrepresent others' claims, Nemo.

[Edited on 28-7-2016 by blogfast25]

NEMO-Chemistry - 27-7-2016 at 15:05

Quote: Originally posted by blogfast25  
Quote: Originally posted by NEMO-Chemistry  

The zinc is mostly gone, i will keep trying to find the thread! But from memory i think it was Blogfast that mentioned the Manganese wasnt Dioxide anymore, but i cant remember.



Nope. What I said was that battery electrolyte contains at least 30 % graphite (non-alkaline batteries). That composition, overall, will have changed little over time.

Don't characterise battery electrolyte as 'MnO2', when in reality it's a complex mixture: MnOx, graphite, ZnCl2, even NH4Cl and iron oxides have been found.

And in fully spent batteries the Mn will be predominantly present as Mn(+3) because:

2 Mn(+4) + Zn(0) === > 2 Mn(+3) + Zn(+2)

... is what drives the EMF of the battery.

Please don't misrepresents others' claims, Nemo.


I apologise, i was going by limited memory. I did remember you mentioning Manganese other than dioxide, but i couldnt remember exactly what you had said. Hence why i tried to find the thread.

I did not intend to misrepresent what you had said, rather i knew not to expect Manganese dioxide especially from a spent battery.

I will find the thread at some point as there was some other useful information i cant remember!! Thanks for clearing it up anyway.

As luck would have it some of the larger lantern type batteries i took apart tonight, seem to have pretty much intact zinc casings in them.

So i should at least get some zinc as well, i am not a big fan of the graphite rods. I tend to find they seem to go soft or fall apart much quicker than ones you can buy, but for some things they seem fine.

I also looked at a thermite thread a couple of weeks back, i think there was a discussion on manganese in that as well.

When i finish what i am doing i will search them back out once i have some manganese to work with.

I apologize again if i unintentionally misrepresented what was said.

So much good info on here but finding it again is a nightmare! Time to organize the book marks better lol.

blogfast25 - 28-7-2016 at 08:22

Quote: Originally posted by NEMO-Chemistry  


I apologize again if i unintentionally misrepresented what was said.

So much good info on here but finding it again is a nightmare! Time to organize the book marks better lol.


Thanks.

SM is a great knowledge base but it's poorly indexed.