| Pages:
1
2 |
dann2
International Hazard
Posts: 1523
Registered: 31-1-2007
Member Is Offline
Mood: No Mood
|
|
Lithium (Per)Chlorate cell
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
National Hazard
Posts: 775
Registered: 14-6-2007
Location: Springs Junction, New Zealand
Member Is Offline
Mood: Comfortably Numb
|
|
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
Banned
Posts: 6370
Registered: 29-9-2004
Member Is Offline
Mood: analytical
|
|
@ 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
National Hazard
Posts: 764
Registered: 24-6-2005
Member Is Offline
Mood: No Mood
|
|
Perhaps Dann2 was referring to the attached patent.
Attachment: 3627669.pdf (268kB)
This file has been downloaded 663 times
|
|
|
dann2
International Hazard
Posts: 1523
Registered: 31-1-2007
Member Is Offline
Mood: No Mood
|
|
Hello,
Thats the one. Only 'brine electolysis' afaikr
High Sb, HCl, usualy DTO anode recipe!!!
Dann2
|
|
|
Rosco Bodine
Banned
Posts: 6370
Registered: 29-9-2004
Member Is Offline
Mood: analytical
|
|
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 .
|
|
|
Xenoid
National Hazard
Posts: 775
Registered: 14-6-2007
Location: Springs Junction, New Zealand
Member Is Offline
Mood: Comfortably Numb
|
|
Perchlorate (not) by gouging rod!
@ 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
International Hazard
Posts: 1523
Registered: 31-1-2007
Member Is Offline
Mood: No Mood
|
|
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
National Hazard
Posts: 775
Registered: 14-6-2007
Location: Springs Junction, New Zealand
Member Is Offline
Mood: Comfortably Numb
|
|
| 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....
|
|
|
chloric1
International Hazard
Posts: 1075
Registered: 8-10-2003
Location: GroupVII of the periodic table
Member Is Offline
Mood: Stoichiometrically Balanced
|
|
Thank you
@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.
Fellow molecular manipulator
|
|
|
Rosco Bodine
Banned
Posts: 6370
Registered: 29-9-2004
Member Is Offline
Mood: analytical
|
|
Overvoltage ??? Catalytic Selectivity ???
WTF is that ?????
Shhhhh ....hear the distant sound .....
( of old Rosco ......ROFLMAO !!!!)  
Sorry ....couldn't resist
|
|
|
Xenoid
National Hazard
Posts: 775
Registered: 14-6-2007
Location: Springs Junction, New Zealand
Member Is Offline
Mood: Comfortably Numb
|
|
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
International Hazard
Posts: 1523
Registered: 31-1-2007
Member Is Offline
Mood: No Mood
|
|
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
International Hazard
Posts: 1075
Registered: 8-10-2003
Location: GroupVII of the periodic table
Member Is Offline
Mood: Stoichiometrically Balanced
|
|
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?
Fellow molecular manipulator
|
|
|
dann2
International Hazard
Posts: 1523
Registered: 31-1-2007
Member Is Offline
Mood: No Mood
|
|
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
International Hazard
Posts: 1523
Registered: 31-1-2007
Member Is Offline
Mood: No Mood
|
|
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
|
|
|
Xenoid
National Hazard
Posts: 775
Registered: 14-6-2007
Location: Springs Junction, New Zealand
Member Is Offline
Mood: Comfortably Numb
|
|
Lithium perchlorate (a footnote)
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]
|
|
|
hashashan
Hazard to Others
Posts: 255
Registered: 10-10-2006
Member Is Offline
Mood: No Mood
|
|
isnt the carbonae Li2CO3?
|
|
|
Xenoid
National Hazard
Posts: 775
Registered: 14-6-2007
Location: Springs Junction, New Zealand
Member Is Offline
Mood: Comfortably Numb
|
|
| Quote: | Originally posted by hashashan
isnt the carbonae Li2CO3? |
Whoops! Yes of course it is! I'll edit the above!
|
|
|
hashashan
Hazard to Others
Posts: 255
Registered: 10-10-2006
Member Is Offline
Mood: No Mood
|
|
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
National Hazard
Posts: 775
Registered: 14-6-2007
Location: Springs Junction, New Zealand
Member Is Offline
Mood: Comfortably Numb
|
|
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
Hazard to Others
Posts: 255
Registered: 10-10-2006
Member Is Offline
Mood: No Mood
|
|
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
International Hazard
Posts: 1523
Registered: 31-1-2007
Member Is Offline
Mood: No Mood
|
|
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
Hazard to Others
Posts: 255
Registered: 10-10-2006
Member Is Offline
Mood: No Mood
|
|
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
National Hazard
Posts: 775
Registered: 14-6-2007
Location: Springs Junction, New Zealand
Member Is Offline
Mood: Comfortably Numb
|
|
@ hashashan
Are you putting to much current through your cell, what current density are you running at, have you tried lowering the current!
|
|
|
| Pages:
1
2 |
![[*]](images/xpblue/default_icon.gif){kind=icon}
