Sciencemadness Discussion Board - Lithium (Per)Chlorate cell

Lithium (Per)Chlorate cell

dann2 - 15-12-2007 at 12:56

Hello,

Though I should stick this in a new thread.

Started up a Li (Per)Chlorate cell.
Anode is Doped Tin Oxide on Ti substrate.
Current density on anode approx. 180mA per square cm.
SS cathodes (two).
Will Perchlorate form easily and in great abundance??
We shall see.
According to US 3020124 it does:

Anode assembly below.

Dann2

Xenoid - 15-12-2007 at 13:36

My gouging rod-based cell;

http://www.sciencemadness.org/talk/viewthread.php?tid=9572&a...

has now been going for 19 days.

I have been manually maintaining the current at 3 amps, it started out at 3.5 volts but now requires 3.9 volts. Not sure if this is because it is converting to a perchlorate cell or the fact that the gouging rods are almost consumed and there is corrosion on the contacts. I haven't bothered with a runtime calculation, but I can't see it lasting much longer! I can't see what's going on inside, because it's all thick, black and goopy looking!

Rosco Bodine - 15-12-2007 at 15:16

@ dann2

A couple of times you have made reference to a patent
you found where the DTO was actually being used alone as a working anode coating , but I don't know if you gave a patent number or not , or whether it was a chlorate
and/or perchlorate anode coating . Please provide that reference if you have it .

I have been looking at the various additive and doping
schemes which are used for achieving the needed oxygen overpotential to get decent cell efficiency for a baked anode , without having to resort to precious metal oxides
or an electrodeposited PbO2 working coating .

Whatever would work acceptably well for the sodium perchlorate cell would almost certainly work even better
in the lithium perchlorate cell .

jpsmith123 - 15-12-2007 at 18:17

Perhaps Dann2 was referring to the attached patent.

Attachment: 3627669.pdf (268kB)
This file has been downloaded 650 times

dann2 - 15-12-2007 at 19:36

Hello,

Thats the one. Only 'brine electolysis' afaikr

High Sb, HCl, usualy DTO anode recipe!!!

Dann2

Rosco Bodine - 15-12-2007 at 21:24

Yeah I've had that patent for quite awhile and it
never really seemed significant as being a chlorate
or perchlorate anode , just pretty much a chlorinator
anode . I have seen that patent before but didn't expect the anode to have the oxygen overvoltage needed for efficient perchlorate production . Maybe it does the job
but just doesn't have good enough efficency for the
patent to have claimed it good for perchlorate .

Perchlorate (not) by gouging rod!

Xenoid - 17-12-2007 at 20:24

@ Dann2

After your recent comments in the Co oxide anode thread, I thought it prudent to pip you to the post again, in checking for perchlorate production...

Clearly, I have misunderstood how this cell was meant to operate. I, in my ignorance was thinking that it would run for a certain length of time, until certain concentration and electrical parameters were reached and then suddenly start producing perchlorate!

I now gather the idea is that perchlorate would start to be produced as soon as chlorate became available!

My cell has been running now for 21 days - this equates to 1512 Amp hours. What the hell it has been doing with all this power I know not! I guess I should knuckle down and do a few calculations, this seems incredibly inefficient!

One thing it hasn't been doing is "producing perchlorate freely and in great abundance". In fact it hasn't produced any perchlorate whatsoever, not even the slightest hint of purple with methylene blue...

BTW anyone wanting methylene blue, I got mine from an aquarium supplies shop, it's used for fish diseases. It's a 1% solution, so you need to dilute it to about .3%.

dann2 - 17-12-2007 at 21:52

Hello,

The all thoses amps can sound like a terrible lot of power but its a low voltage. The cell is all the time warm, some goes into splitting water (O and H leaves the cell) some goes inTO the Chlorate.

Thats the way the patent says it goes. They are using Pt remember so it probably does not happen for Graphite. Keep the faith perhaps when the CHlorate gets to a certain conc...... who know. I have me doubts.
Are you getting much black mess. If you seen black mess getting worse faster it is an indication that Chlordie level is getting lowish. (as least for Na or K.)

I read somewhere that the reason that Li Perchlorate formes easily and in great abundance is because is the small radius of the Li ion. Does not make sense to me as the Li is a spectator ion, and got nothing to do with reactions.

I have just checked mine, no Perc. I THINK DTO is a hopeless Chlorate maker but good at Perk. ??????? Perhaps not.

How much LiCl did you put into cell?

Dann2

Xenoid - 17-12-2007 at 22:10

Quote:

Originally posted by dann2

How much LiCl did you put into cell?

Dann2

Not particulary concentrated, approximately 160g LiCl in a 400ml cell.

The cell has been black with gouging rod gloop since day one!

By my calculation 5.29KWh at NZ 18cents/KWh that's 95 cents, good value for entertainment and heating the garage plus a little chlorate thrown in....

Thank you

chloric1 - 18-12-2007 at 19:10

@Xenoid,dann2--Thank you both alot! You have just eliminated two possibilities for possible perchlorate production and in the process affirming the need for an actual catalyst with higher oxygen overvoltage.

Hope is not lost a solution is not far from here even if we are just reinventing the wheel. The purpose of our quest is the art of chemical manipulation. The science fascinates and inspires us but ultimately it is the thrill of performing successful synthesis. We as individuals develope a closer bond with the universe in turn. :cool:

Rosco Bodine - 18-12-2007 at 20:37

Overvoltage ??? Catalytic Selectivity ???
WTF is that ?????

Shhhhh ....hear the distant sound .....

( of old Rosco ......ROFLMAO !!!!)

Sorry ....couldn't resist :cool:

Xenoid - 20-12-2007 at 23:25

Well...! My Li (per)chlorate gouging rod cell finally died after 23 days. I am now processing the filthy, disgusting contents (three filterings, 2 boilings, 1 alum deflocc.).

Holy Grail anode, where for art thou...!

I am going to put the cleaned up contents into another small cell with a small piece of "scrap" platinum as an anode. Now we shall see if perchlorate forms "easily and in great abundance"....

dann2 - 21-12-2007 at 12:56

Hello,

Checked my Li Chloride cell yesterday and there was Perchlorate present. I had not checked it for the previous 32 hours so it may have
started to form some time previous. DTO anode used at 180mA/cm squared.
The cell contains 1.9 moles LiCl. Approx. 462 amper hours had passed into cell when I noticed Perchlorate.
This cell has a theoritical (chlorate) run time of 305 amper hours. (That's all Chloride converted to Chlorate at 100% current efficiency).
The Perchlorate appeared approx. when it would appear in an Na cell IMHO.
No 'forming with great ease and in great abundance'.
I was using the 5v (+ resistor) from a pc supply for the power supply. I noticed the current going down two days ago. The anode was close to fully pasivated today.
It appears that Li is more erosive (much more) than an Na cell on a DTO anode.
The anode I had used in the Li cell had very little work done before being used in the Li cell and it only lasted
7 days or so in the Li cell . I switched my other (trusty) DTO anode that has been running now for approx. 300+ hours into the Li cell to keep it going.

The voltage accross the Li cell was about 2 volts higher that when the anode was in the Na cell at a similar current density.
After about 1.5 hours my trusty (300+ hours and was still going OK) DTO anode had
passivated. It would appear that Li Chloride cells are erosive to DTO.

Dann2

"Perchlorate forms easily and in great abundance" my arse!!

chloric1 - 21-12-2007 at 14:59

Oh well, better luck with something else.

I wonder if the small size of the lithium ion makes the chloride more chemically active? Lithium aqueous chemistry is like a cross between groupI alkali ions and magnesium ions. I know group II have smaller ions because they give up more electrons. Lithium only gives one but it is so small that maybe it behaves half ass like magnesium because of this. Am I on to something or just stoned out my mind?

dann2 - 21-12-2007 at 16:16

Hello,

I read somewhere that the reason for the 'Perchlorate forming 'easily and in great abundance' was becasue of the small size of the Li ion. But the Li is a spectator ion?

Dann2

[Edited on 22-12-2007 by dann2]

dann2 - 22-12-2007 at 10:25

Hello,

As I stated above the Li electrolyte has 'passivated' my trusty DTO anode that had been running for some hundreds of hours in an Na cell. Funny thing is it is still going but you have to put a rather high voltage accross the cell to get current to flow. When the anode was in the Na cell about 7 volts was good for one amp.
Now it takes 12 volts for 0.3 amp. I am just going to let it run and run untill anode fails completely.
I added a quantity of KCl to a sample from the Li (Per)Chlorate cell and got the 'yogurt' type ppt of K Perchlorate. ie: There is quite a concentration of Perchlorate in the cell.
The Li seems to be somewhat easy to make Perchlorate from but not anything to write home about.
And since the Li cell does not form Perchlorate with Graphite easily (as shown by Xenoid) then it is not much addition to the home Perchlorate maker.

Dann2

Lithium perchlorate (a footnote)

Xenoid - 20-1-2008 at 20:20

With all the talk about perchlorates lately, I thought I would add a footnote to the lithium perchlorate cell thread. My final yield of LiClO4 was 324g of LiClO4.3H2O (see attached image).Somewhere along the line I must have decided not to bother trying to extract any more and disposed of the "mother liquor", unfortunately I don't remember where. I have a horrible feeling I threw it in my K+ Na+ Cl- ClO3- ClO4 "slops" container for recycling. According to my calculations there is quite a bit of "missing" Li.

Basically I started with about 224g of pottery grade Li2CO3, using HCl, I converted this into about 250g of LiCl in 800 mls of solution after filtration. I reduced this to about 600 mls by evaporation and used 400 mls in the cells, ie. two thirds.

So effectively I used 148g of Li2CO3, theoretically this converts to 165g LiCl, which converts to 351g LiClO3 in the chlorate cell which converts to 413g LiClO4 in the perchlorate cell. This is the equivalent of 621g of LiClO4.3H2O. My recovered amount is only 52% of the theoretical, there is a lot of missing Li and I dont know what happened to it!. Some was obviously lost cleaning up the chlorate cell mess! Given the length of time the two cells were running, the Li should have all been converted to LiClO4, I should have just evaporated the entire cell contents to dryness!

Depending on the mode of crystallisation, the LiClO4.3H2O formed a dense felted mat of tiny aciculate crystals a few mm long, but on one occasion I noticed a mass of needle-like crystals upto 2 to 3 cm long.

The smaller quantity 74g in the image is what I separated out first. I tried to recrystallise it by slow evaporation on the hot water heater, to try and grow some large crystals. Unfortunately it is so hygroscopic, it just sat there for 2 weeks doing nothing. I finally evaporated it down, and by mistake let it go to dryness and actually melt while I was doing something else! When I found it there were acrid fumes coming from it. I dragged it of the burner, and it set to a hard white lump, which I couldn't remove, so I redissolved it and dried it in the oven, where it was still emitting acrid fumes for a while.

Both lots were dried at 125 oC. for about 2 days, cooled in a descicator under vacuum and packed in the plastic bags.

Edit: Changed LiCO3 to Li2CO3 ...!
[Edited on 20-1-2008 by Xenoid]

[Edited on 21-1-2008 by Xenoid]

LiClO4.jpg - 10kB

hashashan - 21-1-2008 at 04:10

isnt the carbonae Li2CO3?

Xenoid - 21-1-2008 at 05:38

Quote:

Originally posted by hashashan
isnt the carbonae Li2CO3?

Whoops! Yes of course it is! I'll edit the above!

hashashan - 21-1-2008 at 06:22

Anyway, dont you think that your solution was too diluted?
I am planning to run a Li perchlorate cell with mmy PbO2 anode but with 500g of LiCl dissolved in 600ml's.
However I dont plan to precipitate the LiClO4 out of the solution, I want to make AP out of it.

Xenoid - 21-1-2008 at 10:28

Yes, I suppose in retrospect it was! Really, I was just trying out the procedure!

My Li2CO3 was a 500g bag from the potters supplies, I had already used some of it, and didn't want to use all the rest. The 224g I started with was 3 moles (allowing for impurities) to keep calculations simple. This required about 220g of HCl to react (my HCl is 290g/L, so that was about 750 mls). After filtering, and washing, this increased to about 800 mls, after evaporating it down to 600 mls, I couldn't be bothered going any further.

Also, for some reason, I was thinking the LiClO4 was very soluble, like NaClO4. When I realised it wasn't, I used a bigger cell size for the perchlorate conversion, to avoid it crystallising out in the cell. So I diluted the contents of the chlorate cell as well ...

hashashan - 21-1-2008 at 14:38

Actually If you use a saturated LiCl solution the LiClO4*3H2O should crystallize out of the solution .... actually about 75% of should crystallize out

dann2 - 22-1-2008 at 11:20

Hello,

Paper here that may be useful. Thanks to Solo.
(In reference section in Papers wanted...........)

http://www.sciencemadness.org/talk/viewthread.php?tid=9319&a...

THE SYSTEM LITHIUM CHLORATE – LITHIUM CHLORIDE – WATER AT VARIOUS TEMPERATURES.pdf

Dann2

hashashan - 28-1-2008 at 11:16

Guys, something weired is going on.
I installed my LD anode into a LiCl cell. wil average conc. about 50g/100ml, and then .... 20 minutes run and a brown cloud is appearing.. definite signs of heavy erosion. I did get some erosion in a NaCl cell also .. but nothing like that.... anyone got a smart thing to say?

Xenoid - 28-1-2008 at 13:27

@ hashashan

Are you putting to much current through your cell, what current density are you running at, have you tried lowering the current!

hashashan - 28-1-2008 at 13:44

the density is not too high
about 300ma/cm^2

Xenoid - 28-1-2008 at 14:00

Well I think that is very high!

I don't even run Pt that high, but I'm pretty conservative on this aspect!
None of my homemade "oxide" based anodes seems particularly stable above 100mA/cm^2. I would suggest you lower the current density by at least half, see what happens!

chloric1 - 28-1-2008 at 14:06

hashashan- You may have to run slightly below 100mA/cm2 given what dann2 experienced in trying his DTO anode. Apparenty the lithium chloride is more erosive towards anodes than its sodium counterpart.

hashashan - 28-1-2008 at 14:15

Well lowered it to about 150ma/cm2 ..... Ill lower it to 100 just in case and let it run for a day

I don't know ... I usually run the PbO2 at 300-500 with NaCl and there is only slight erosion ... not too much about half a gram per 350g of NaCl

But with the LiCl I got a really brown solution in only half an hour ... I never saw that dark solution with the NaCl .. not even after a week at 400ma/cm2

Anyone tried Barium Chloride?

Update:
Setting it to 150mA/cm2 helped a lot.
after 12 hours there is some erosion but not as near as it was at 300mA/cm.
I would go down to 100mA/cm2 but it will take for ever to finishe the process.
It will take 20 days only for the chlorate, supposing that the cell efficiency is 50%

[Edited on 28-1-2008 by hashashan]

[Edited on 29-1-2008 by hashashan]

hashashan - 17-2-2008 at 15:56

Well its been 20 days already
no perchlorate has yet formed ... Is it possible that a cell with a conc. solution and magnetic stirring will be less efficient then 50%???

anyone has any ideas why is it taking so long?

dann2 - 17-2-2008 at 16:26

Hello Hashashan,

I can't figure out from the posts how much LiCl you have in your cell.
50g per 100ml? How big is the cell 600ml?.

The efficiency may be below 50%.
Keep going.
At least when you do get to the Perchlorate stage things will finish up soon enough.

Dann2

Xenoid - 17-2-2008 at 16:57

Quote:

Originally posted by hashashan

no perchlorate has yet formed ...

Hashashan - have you made sure the (non)perchlorate solution from the cell was cool. If you remember, I found the Methylene Blue test doesn't work at temperatures above about 35 oC.

Methylene Blue Testing: http://www.sciencemadness.org/talk/viewthread.php?tid=9783&a...

Dann2 has also verified this. Make sure you cool your solution to, say, about 15 oC. first before doing the test!

tentacles - 17-2-2008 at 18:16

Quote:

Originally posted by hashashan
Well its been 20 days already
no perchlorate has yet formed ... Is it possible that a cell with a conc. solution and magnetic stirring will be less efficient then 50%???

anyone has any ideas why is it taking so long?

I did read somewhere that stirring the cell contents was detrimental to efficiency. One of those older JES papers. It was significant in some of their tests - as much as 30% in cases were previously high effs were achieved. In low eff tests the difference was like 10-15%.

[Edited on 17-2-2008 by tentacles]

hashashan - 17-2-2008 at 23:28

Its a 6-7 mol cell ... the 6-7 is due to the fact that I added more lithium chloride as the solution evaporated. the volume is 1 liter

hashashan - 26-2-2008 at 07:46

ARGGGGGGGGGGGG
still no perchlorate . It really starts to piss me off.
I increased the voltage and now the cell is running at about 7 amps. that is about 250ma/cm2. hopefully that will help.
As the chloride level decreased I cant see any signs of erosion even at that current density(just like with Na).

@Xenoid : my solution temp. is quite low as it is ... about 20 degrees. Also when the perchlorate levels get high then the test work even in higher temperature.

chloric1 - 26-2-2008 at 15:11

not a good sign hashhashen, it has been 30 days I believe

. The ions are conspiring against you. Did you get perchlorate when you used NaCl? I don't remember if you added a catalyst like a fluoride or a persulfate. Are you getting high chlorate? IF so then maybe your chlorate is being reduced at the cathode. Don't know but trying using a bigger cathode.

hashashan - 26-2-2008 at 21:25

I got slight signs f perch

and my cathode is twice the size of the anode