making potassium (per) chlorate

[Mumbles]

For larger quantities, you can probably contact your local Culligan type place, and get some bulk water at better prices.

[Bonny]

For larger quantities, you can probably contact your local Culligan type place, and get some bulk water at better prices.

 

 

That's what I did, after buying 4l jugs a few times. Much cheaper than a grocery store, but still a lot more than tap water...

[bikemaster]

Where do you live???

Where I live, I can't have distilled water for 2$ for 5 gal. You just have to buy the bottle and they refil it for 2$ (bottle cost 10$ if you not have already some). Some poeple prefer to drink distilled water, it is why they make some at low price.

[Swede]

Let's think about what is in tap water. Again, if you are doing true lab work, and are attempting to analyze the products from a run, RO, DI, or distilled would be best. But for bulk execution of oxidizer, the contaminants delivered by even nasty tap water is going to pale by comparison to what is left behind depending upon your collection technique. You will add minute amounts of chloride, possibly hypochlorites (bleach) from tap water, but in comparison to what the cell itself produces, it is orders of magnitude less. If you feel the need to recrystallize for a really pure product, I wouldn't hesitate to use good water, but for general use, I don't think there is a problem. Remember, whatever collection method you use, it will probably be designed to leave behind highly soluble contaminants, and whether these are from the water, or from the cell itself, I don't think it makes a lot of difference. It should all, in theory, get stripped by either a good wash or especially by recrystallization.

 

My biggest cell is about 24 liters, maybe 8 gallons. By the time I've prepped the electrolyte, created acid and top off, and also created wash water, I'm usually at 12 gallons (48 liters) or more, used. I do tend to use distilled for washing if I have it on hand in bulk; I think it does help.

[tentacles]

TY Swede, I don't see why there's so much fuss about the tap water for this - most KCl is labelled as 99% pure - there's already a LOT more contamination in your salt than your tap water is likely to provide.

 

Although, an often cheaper source of decent water is local pet/aquarium shops. A lot of aquarium types need the purity for various reasons. I know we used to refill 5 gallon jugs for $1 with good clean TFC membrane RO water. Water going in to the unit was 300-400 ppm TDS and coming out, 8-30 ppm.

 

If you're really set on using clean water for it, you can get an RO unit for pretty low money these days.

[Bonny]

TY Swede, I don't see why there's so much fuss about the tap water for this - most KCl is labelled as 99% pure - there's already a LOT more contamination in your salt than your tap water is likely to provide.

 

Although, an often cheaper source of decent water is local pet/aquarium shops. A lot of aquarium types need the purity for various reasons. I know we used to refill 5 gallon jugs for $1 with good clean TFC membrane RO water. Water going in to the unit was 300-400 ppm TDS and coming out, 8-30 ppm.

 

If you're really set on using clean water for it, you can get an RO unit for pretty low money these days.

 

It's to late for me now. I think after this run I won't be needing any chlorate for a LONG time. In future though, I'll definitely save the $$ and use tap water in the cell. Maybe another option to clean the tap water would be a Brita or similar filter, one cheap easy step that would do no harm.

[Swede]

Although, an often cheaper source of decent water is local pet/aquarium shops. A lot of aquarium types need the purity for various reasons. I know we used to refill 5 gallon jugs for $1 with good clean TFC membrane RO water. Water going in to the unit was 300-400 ppm TDS and coming out, 8-30 ppm.

 

If you're really set on using clean water for it, you can get an RO unit for pretty low money these days.

 

Yeah the new RO units sold to reef aquarium keepers are not always cheap but they do work well. Or, you can buy the water at a pet store with your own jug. For a really serious amateur chemistry lab, if you don't want to mess with distillation, you can run reverse osmosis water through a disposable deionization cannister, and what comes out is as good as anything you can buy or distill.

 

But for general use, tap is fine.

[WSM]

TY Swede, I don't see why there's so much fuss about the tap water for this - most KCl is labelled as 99% pure - there's already a LOT more contamination in your salt than your tap water is likely to provide.

 

Although, an often cheaper source of decent water is local pet/aquarium shops. A lot of aquarium types need the purity for various reasons. I know we used to refill 5 gallon jugs for $1 with good clean TFC membrane RO water. Water going in to the unit was 300-400 ppm TDS and coming out, 8-30 ppm.

 

If you're really set on using clean water for it, you can get an RO unit for pretty low money these days.

 

We got an under-sink RO unit for the kitchen and it works well (according to the TDS tester). My water going in has 300-400 ppm (depending on the time of the year) and 10-20 ppm coming out (and tastes considerably better, by the way). I plan to use The RO water when I'm ready to run the 25 liter cell; why add extra contaminants when I have the cleaner water available?

 

I got the RO unit from Costco a couple years ago for around $150. If they're not in the store, look at costco.com and see.

[50AE]

I've wondered if these MMO electrodes are suitable for the electrolysis of bromides into bromates (barium, strontium)

[Arthur]

You always have to consider the cathode reactions too. Barium certainly has some adverse reactions and may precipitate out at the cathode.

With strontium you would have to check the solubilities.

 

You may likely have to go via electrolysing the sodium salt for cell conductivity then exchanging the cation for function.

[Swede]

You may likely have to go via electrolysing the sodium salt for cell conductivity then exchanging the cation for function.

 

This is the way perchlorates are made commercially, starting with the phenominally soluble sodium perchlorate and then substituting; metathesis. If the desired (per)chlorate has a much lower solubility than the sodium (which will almost always be the case) then the yields should be fine.

 

An advanced lab would have indicators and titration setups to determine the percentages of species, such as the ratio of perchlorate to chlorate during electrolysis, and the trick on the amateur level would be to be sure your perchlorate is pure; otherwise, you'll end up with a possibly dangerous mix of chlorates and perchlorates when the substitution s made. Ammonium, of course, is the kicker... you CANNOT have chlorate anywhere near ammonium. The perchlorate used to create ammonium perchlorate must have zero chlorate in it so as to avoid explosive and unstable ammonium chlorate.

 

With all that said, with the exception of ammonium, I can't see much of a reason NOT to try some of the other cations from the chloride. This is where a small test anode would rock, something 1" X 3", so if all the MMO falls off, no big loss. Obviously approach with caution, look at the solubilities, and see if it is possible. Some MMO formulations (iridium, tantalum) rather than ruthenium might do a better job. It's a wide-open field.

 

Just no ammonium chloride!

[Bonny]

I will soon have my Pt anode ready (waiting for some other parts, and for my last chlorate run to finish). I'm now wondering about the ozone produced when the cell is running. If I run a 15-18l cell, will the amount of ozone produced be a hazard if run indoors? My chlorate cell is outdoors, but the weather is quite cold and I doubt I'll be pumping enough current into the cell at this stage (chlorate to perc) to keep the temp up. I might have to wait until spring but would prefer not to... Edited December 18, 2009 by Bonny

[50AE]

I don't know how this happened.... :(

 

http://img525.imageshack.us/img525/347/pict0029d.th.jpg

 

I will tell you the story from yesterday :

 

I was disappointed why the amps at 5 volts became lower and lower. So I pumper 12V with another power supply and the amps increased at 15-16A. I put the cell in water outside. The temp outside was -5C. The cell was very warm, as the water around it. It ran for 2-3 hours, when suddenly I spot the ampermeter - there was no current. I took the cell outside and the electrodes looked okay.

 

Today, I was trying to know why there's no current flowing. The power supply was ok, so was the ampermeter, the wires and the connections. I thought that the solution was weak in chloride, so I took all the chlorate at the bottom and I put 3-4 spoons of chloride like I've done some times before. I connected everything and put the electrodes in the cell. There was still no current.

After 10 minutes of soaking in the electrolyte, the current started to increase slowly. In 30 minutes, it reached 8A and the electrolyte become hot. I took the lid out and what did I see - a milky solution of erroded titanium and the MMO falled. I couldn't believe my eyes.

 

What I suspect mainly : Is the weilding, because :

-The amps have always been dropping. I haved to increase the voltage to keep up the same amps.

-Today, when I was sinking the electrodes, there was no current flowing, until I sank them completely where the titanium strips welded to the anode and cathode touched the electrolyte. When I was tooking the electrodes half way out, the current stopped flowing again and this is not normal. When the half of the electrodes are sunk, there still must be current flowing.

 

 

My thought is : I've abused the welding during usage and trying high amps. And I think that today, it became apparent. Maybe the MMO was sinking with a very bad connection between the strip and there was no or little current flowing through it. The MMO mesh wasn't current protected and was sunk in a very hot electrolyte, which I think led to its destruction.

And another fact that makes me thinking of this - there were sparks burning from the welding part when I oppened the cell.

 

 

I'm very sorry Swede

Edited December 17, 2009 by 50AE

[Bonny]

My thought is : I've abused the welding during usage and trying high amps. And I think that today, it became apparent. Maybe the MMO was sinking with a very bad connection between the strip and there was no or little current flowing through it. The MMO mesh wasn't current protected and was sunk in a very hot electrolyte, which I think led to its destruction.

And another fact that makes me thinking of this - there were sparks burning from the welding part when I oppened the cell.

 

 

I'm very sorry Swede

 

I don't know what size of anode you have (had) or what size the Ti shank was, but I can't see it failing at only 8A. Also, in the pic it looks as if both ends of your anode are corroded, not just the end that was attached to the strap. I've run mine as high as 30A with no problems. When I noticed, though, I quickly adjusted spacing to bring the current back to 20A and not kill my power supply.

[Swede]

I'm very sorry Swede

 

YOU have nothing to be sorry about! No worries, I'll send you another. PM me you address once more if you don't mind.

 

You might have gotten one of the older anodes that used spot welder MK 1 rather than my newer unit.

 

Looking very closely at your picture, something is odd to me... the total erosion of the Ti strap above the anode. Your description of what happened makes me think this:

 

Ti normally passivates and is self-protecting, but ONLY BELOW A CERTAIN VOLTAGE. If you jam enough voltage on them, the oxide skin will break down, the protection will vanish, and even Ti will fall apart like some crappy pot metal. In all cases, try to keep the voltage well below 10, preferably a chlorate cell should never be higher than 7.

 

Assuming the electrolyte was normal, adequate chloride concentration, what might have happened is that the spot welds were weak, and they slowly failed, preventing current from flowing. You dialed up the voltage a bit to see what you'd normally expect, and it exceeded the ability of the Ti to protect itself, and since both the shank and the mesh are Ti, they died on you.

 

Don't worry, we'll get you going quickly enough. But in an odd way, congratulations! I have NEVER seen a Ti strap dissolve like that. It is a valuable lesson.

[Swede]

I will soon have my Pt anode ready (waiting for some other parts, and for my last chlorate run to finish). I'm now wondering about the ozone produced when the cell is running. If I run a 15-18l cell, will the amount of ozone produced be a hazard if run indoors? My chlorate cell is outdoors, but the weather is quite cold and I doubt I'll be pumping enough current into the cell at this stage (chlorate to perc) to keep the temp up. I might have to wait until spring but would refer not to...

 

Bonny, if you don't vent the cell to the outdoors, I am afraid you might find the ozone both very noticeable and approaching the irritating. O3 is pretty nasty and not too good for you. Even if it's nothing more than a towel blocking 99% of the bottom of a window, and a tube stuck through, I think it'd be better than nothing. But if your current is low, maybe you won't notice a thing.

 

Perchlorate is a much cleaner process than chlorate. no chlorine, much less fuming and gassing, no bleach, etc. Give it a shot, but I'd recommend you be prepared to modify it to vent appropriately.

[Bonny]

Bonny, if you don't vent the cell to the outdoors, I am afraid you might find the ozone both very noticeable and approaching the irritating. O3 is pretty nasty and not too good for you. Even if it's nothing more than a towel blocking 99% of the bottom of a window, and a tube stuck through, I think it'd be better than nothing. But if your current is low, maybe you won't notice a thing.

 

Perchlorate is a much cleaner process than chlorate. no chlorine, much less fuming and gassing, no bleach, etc. Give it a shot, but I'd recommend you be prepared to modify it to vent appropriately.

 

 

I'll keep this in mind when I get the cell assembled. I would prefer not to have a window less than 100% shut for the next few months, as Jan and Feb are usually the coldest months...sometimes as low as -40C (plus windchill). I am planning on running 8-10A in my cell (and hoping my anode lasts...I have about 20kg of chlorate to convert)

[Lithium]

@50AE What sort of water are you using. If it is drinking watet there is hardly enough Flouride in it it corrode the Ti. Flouride is supposed to corrode Ti.

Check supply Voltage with a volt meter to make sure is is putting out 12 Volts and not more.

[50AE]

My drinking water is very pure and I'm sure it's not the reason.

[Swede]

Some experiments with a drip (gravity fed) HCl system... posted also on Science Madness DB.

 

We have discussed this in some detail in the past. I previously used a peristaltic pump with a good timer to deliver the HCl based upon an electrical current rule of thumb. The problem was the coarseness of the delivery, and the fact that the tubes from the pump to the cell often filled with gas between HCl deliveries, making precision difficult.

 

I decided to attempt a drip system, and the initial results show great promise. A drip system consists of three important components:

 

1) An electrically-activated solenoid valve

2) A metering or flow valve

3) A decent timer capable of good precision

 

Obviously too, you need a vat of HCl positioned above the system.

 

All of the components must be impervious to HCl, either concentrated (near 32%) or dilute. I picked up a surplus 12VDC solenoid valve that has 100% PTFE wetted surfaces. This one was from Cole Palmer, but others would do fine. Next, an Aalborg VT-PTFE needle valve was obtained; again, all PTFE where it counts. I turned up an adapter from Teflon to connect the two, although PVDF hose barbs would do fine as well.

 

http://www.5bears.com/perc/drip001.jpg

 

The vat of "HCl" (water for now) was positioned 1/2 meter above the assembly.

 

http://www.5bears.com/perc/drip002.jpg

 

Applying 12V to the solenoid triggered it to the ON state, and the water began to flow through even the narrow tubing (1/8" or 3mm ID) rapidly. Working the excellent Aalborg needle valve allowed a very precise control, down to 1 drop every 10 seconds or so:

 

http://www.5bears.com/perc/drip003.jpg

 

The only thing that is going to alter the flow of this unit is head pressure. As the HCl vat depletes, the flow rate will drop off. But experimentation with positioning of the vat showed that the effect was very minimal. If the level of the HCl drops 10 cm, but the overall height of the vat is at 200 cm, the head pressure will vary at worst 5%, and in reality, since the flow rate is so slow, the actual delivery variation is even less.

 

The Aalborg needle valve produced a control so fine that possibly the timer itself could be skipped, and the HCl delivered on a continuous basis... but I still prefer the concept of timed delivery.

 

Overall, though, gravity feed eliminates a lot of the expense and hassle of HCl delivery. One important aspect is that it must be engineered well; otherwise, the possibility exists of a leak draining the entire vat and causing a mess or hazard, but we are only dealing with a couple of PSI or maybe 150 millibar, depending upon the height of the vat.

 

The most expensive component was the Aalborg needle valve. I bought mine new for $45 US, because I could not find one used on eBay. The solenoid was maybe $10 NIB on eBay.

 

A less fancy rig could be made up with cheaper components, and still get excellent results. How about a $2 pinch clamp on the tubing, setting the system up for a continuous IV drip?

 

Gravity-fed HCl is the way to go!

 

Cheers, & Happy new year!

[Swede]

Pt Porn

 

My long-delayed raw 3 micron Pt over Ti mesh finally arrived. I absolutely have not given up on LD and other anode attempts, but I did want some Pt mesh to experiment with.

 

http://www.5bears.com/perc/ptmesh04.jpg

 

http://www.5bears.com/perc/ptmesh03.jpg

 

Pt is expensive - in any form. A reagent-grade salt to pure Pt metal; it doesn't matter. I think in the end, it would cost as much to plate an anode with an equivalent Pt coating beginning with a Pt salt, as simply buying this material from the start. The Pt load of this mesh is 50 grams per square meter.

 

I am probably going to craft tubular Ti shanks for these, filled with Pb, to fit a 1/2" PVDF compression fitting.

 

Some of you guys may have noticed my Agora ad for MMO and Ti electrodes is down... this is temporary. I have a new work process producing a slightly larger anode as a standard item (3" X 6" vs. 3" X 5") and I can still make them to any size. I am going to rewrite the ad. The price should still be less than 1/2 of what the normal sources are, but the labor to make them is not trivial and the price will probably go up a bit from the "sale" prices on the last ad. Those promised anodes at the quoted prices will get them at those prices.

 

I am not making buckets of cash from this, it is more a matter of making these accessible to hobbyists. I've got enough MMO material for now to produce perhaps 40 more anodes at 3" X 6". If interested, keep an eye on the Agora section; I should have it up in a few days.

[TheSidewinder]

Youch... Swede, put those pictures here if you can.

 

It took almost 4 minutes to transfer just the bottom one from your site. The other one timed out the first time.

 

Use our bandwidth, not yours.

[Arthur]

With the Pt coated mesh, how do you support it and get current into it? A couple of spot welds seems a bit crude.

[Swede]

TS, do my blogs load that slowly? Every picture I have ever posted here on APC has been on my own web site. Hopefully it was nothing more than a hiccup in this case. I have generally been happy with it. Anyone else having troubles?

 

Arthur, I plan on scraping the Pt off of several of the junction portions down to the Ti substrate, and spot-welding there. I use the same method for MMO, and it does create a really solid weld. A typical interface would have 12 to 16 individual welds, and using my newer spot welder, the junctions compress to a flat disk and it's quite strong. There is no avoiding the loss of Pt in that area, sadly.

[dagabu]

TS, do my blogs load that slowly? Every picture I have ever posted here on APC has been on my own web site. Hopefully it was nothing more than a hiccup in this case. I have generally been happy with it. Anyone else having troubles?

 

Nope, they load almost instantaneously.