387 replies to this topic

[alany]

What kind of electrodes? How big is the cell? What current are you running it at?

[Pretty green flames]

2x Graphite electrodes (Anode and cathode)

Exactly 300ml of saturated KCl solution

and i'm running it at 6volts and 1.7amps (My power supply is only capable of delivering a max of 2amps and it can work at 2amps for only 5minutes before it overheats)

[alany]

It is probably potassium chlorate, are they thin plates rather than truely cubical crystals?

25 hours at 1.7 A is 42.5 Ah. 300 ml of saturated KCl is about 1.6 Moles of KCl. Full conversion at 100% efficiency would require 258 Ah. At the usual efficiencies you'd expect more than 500 Ah, at 1.7 A that's more than 12 days.

[Pretty green flames]

They are small needle like plates.

I'll try to get a pic and post it here.

EDIT: Tried to get a picture but all of them came out very blur, basicly you couldn't see anything

Edited by Pretty green flames, 19 April 2005 - 09:41 AM.

[alany]

Like these ones?

http://www.vk2zay.ne...achment.php/228

[Pretty green flames]

no not really

They're like flat cactus needles but not so sharp.

Maybe that's just becouse of the rapid cooling that took place in the night.

I'll keep it inside the house so it won't be exposed to the sudden temperature changes, and we'll see if something comes out of the solution when it's not beeing cooled down.

[bogsulphur]

i have five hundred grams of potassium perchlorate. its for sale. if you want to buy it, make an offer. i'm pretty sure its lab grade.

[Phoenix]

Pictures of crystals: http://www.wfvisser....ml#crystalshape

[Pretty green flames]

The second picture is what i get.

[alany]

That's pretty typical of rapidly cooled KClO3 from a strong brine solution or growth by evaporation from the surface.

[sasman]

To be continued....

Edited by sasman, 29 April 2005 - 11:25 PM.

[sasman]

Well i finally got to add the 3 phase bridge rectifier to the Arc welder..So i have a fully adjustable DC power supply ..I have been having major problems with my power supplys but this welder has solved all that..

I use a 15 amp Variac to control the amperage of the welder.. this also eliminates the Dangerously high voltage spike you get with the welder when you turn off the power...
I knew it was going to work straight away as i only had to turn up the variac to 20% to get nearly 30 amps ... I am only running this test cell with 2 electrodes so am conservatively limited my self to 60 amps..(using 20 amps per square decimeter altho some patents recommend 40 amps a decimeter which equals 54 amps per Anode !?!.)

..The cell is a 32 litre bucket with 25 litres deionised water + 11Kg of Sodium Chloride.. i have used cooking salt..which on the packet said it contained Salt and an anti caking agent sodium ferrocyanide..My first test batch is just a test to see if everything works ok.. if i have any problems with the final product i will buy pure NaCl..

Cell setup

You can see some undissolved NaCl but this will dissolve as ClO3 is formed..
I am using an under water power head pump 660 litres an hour which supplies the agitation..Without it you can see in this photo that the top half of the cell is opaque due to lots of bubbles..Fizz!!!

I have made my cathodes out of titanium sheet rolled into a cylinder and drilled some holes to help circulation.

Cathodes

You can see that i have used some plastic nuts and bolts to try to help centralise the anode in the cathode..

The actual electrical connection to the anode is made with a 10 mm graphite rod
which is screwed into the GSLD anode.. i did this so that it will hopefully eliminate any wicking of the electrolyte up the graphite and thus corroding the connection..

4 AWG oxygen free copper wire was used rated at 80 amps..this was connected using gold plated connections to a steel hose clamp. i may alter this conection if it proves unreliable..

Electrode Setup


Here are a few photos showing the amperage and voltage at 30 , 40 ,50 & 60 amps..The small multimeter measures the actual curent from the Arc welder at AC current..The large multimeter is measureing actual cell voltage DC..

The small Digital meter is a 0 - 199 amp meter

30 amps 40 amps
50 amps 60 amps


The entire electrode setup was sealed to the bucket lid with silicon sealer..Using plastic nuts and bolts to secure it in place.I will be adding an automatic feed system to keep the electrolyte at a fixed level. i have not decided yet if i will bother to control Ph levels..

When i first started running the cell tonite the first few hours there was a very strong smell of chlorine enough to make me cough...but when i came to turn off the cell for the night there was virtualy no smell at all...

I did notice that one of the graphite electode connections were warmer than the other..At the moment each electrode is connected to the welder individualy..I may change this configuration..

To be continued....

[alany]

Very impressive sasman!

I'm glad you've got the PSU issues worked out.

What's the electrolyte temperature like?

[raketpeter]

Very nice indeed Sasman. Could you elaborate a little more on your electrical anode connections - just how are you avoiding the "wicking" problem?

If the plastic screws you use are made of nylon - they WILL die. I know this for a fact since my cell initially used nylon. Now it's all replaced with homemade screws teflon - it's a pain to make M3 tefon screws, but worth it - they last forever - even when in direct contact with the Pt anode.

Once again - congratulations on your good progress!

[Lil_Guppy]

Well, I have finally gotten around to gathering the equipment to make my own cell. I did a test chlorate cell the other night, just to get a feel for things. It was a short run and only produced 5g of chlorate, but the idea was just to see if it would work for me. Anyway, I was looking around for a suitable anode material, and I think I have settled on some GSLD anodes, but I was searching around on the 'net for platinum foil. I came across this page on the site alany posted about somewhere here (I think). Would something like this work for a perchlorate cell, or would there be problems with it?

Anyway, very nice work sasman What sort of yields are you expecting from your set up?