Pyrophury Posted February 10, 2018 Share Posted February 10, 2018 Your electrical connection will depend on the physical aspects of the setup and the current it's carrying. When in doubt, a copper, clamping connector can be used on the outer surface of the filled titanium lead tube and the power lead solidly bolted to that. I'll try to find a photo of the device, if you need one. Here in the US they can be purchased in large hardware stores or electrical supply houses. I was going to attempt to tap a hole to accept a 6mm brass stud to attach my leads. But if that's not really necessary I think I may end up opting for a simple clamp. Theoretically, yes. I haven't done that yet, but one method to use is to run the cell at the boiling point of the electrolyte, and the boiling off of the water will naturally concentrate the NaClO3 to where it will drop out as the solution cools to room temperature. This is the basis of a US patent that Arthur shared with me a few years ago. The setup is more complicated because of the added hazards of such a setup, but it's entirely possible to do it safely on a smaller scale. That does sound very complicated, I'd like to keep things a simple as possible so perhaps I'll forget the whole salt basket idea for now. Link to comment Share on other sites More sharing options...
WSM Posted February 11, 2018 Share Posted February 11, 2018 I was going to use PVC/UPVC pipe and end cap, I don't intend to run any hotter than 60oC though so it should be OK then, thanks. I did test my electrodes again and increased the temp to around 60oC, but I only got about a .5 increase, for a total of 1.5A at 5V, even with the electrodes very close together. I've also noticed places where the MMO coating has already completely worn down to the bare metal, I only tested it for less than an hour! Perhaps it's the cheap adjustable power supply I've been using? I believe the largest single factor controlling the current demand of a cell is the size of the electrodes and how they're configured. Next is balancing all the other components of the whole setup to match. I noticed that your tubular titanium leads are in line with each other. That's okay if your spacing between them is great enough, but if you're trying to minimize the spacing between the anode and cathode, I've found that offsetting the position of the leads on flat electrodes allows the spacing to be much closer without crowding the lid of the cell. This photo shows an anode and a pair of cathodes with the leads offset (rather than lined up with each other), so the leads going through the lid and their fittings don't crowd each other. It worked well and efficiently with a variable power supply to make sodium perchlorate solution from sodium chlorate electrolyte a few years ago. This style of attaching the leads can be used to greatly adjust the spacing of a single pair of electrodes if the tubes are welded to the opposite side edges of the paired electrodes, by spinning the separate electrodes in their compression fittings (while keeping the flat surfaces parallel to each other). I recall Swede really liked the idea when I shared it with him several years ago. You may want to try something like this on future electrode assemblies and see if it helps. WSM Link to comment Share on other sites More sharing options...
WSM Posted February 11, 2018 Share Posted February 11, 2018 (edited) I was going to attempt to tap a hole to accept a 6mm brass stud to attach my leads. But if that's not really necessary I think I may end up opting for a simple clamp. That does sound very complicated, I'd like to keep things a simple as possible so perhaps I'll forget the whole salt basket idea for now. Whichever method of attachment you use, be sure it's tight enough to carry the full current without overheating (which might cause excessive stress on the compression fittings in the cell lid). I usually make potassium chlorate. When I first ran my sodium chlorate cell experiment, I ran it long enough to get what we theorized to be a complete run. The product was in solution, so I placed the NaClO3 solution in large, clear PET jars in a refrigerator at about 0oC and collected the precipitated crystals a couple days later. The remaining chlorate in the "depleted" liquor is waiting for the next run of the cell after "recharging" it with more NaCl. With a hotter system, the collecting of sodium chlorate crystals should be easier due to the concentrating effect of boiling off the excess water as the cell runs between 105o and 115oC. After the run, cooling the electrolyte naturally (rather than with refrigeration) will yield a crop of chlorate crystals at room temperature, PLUS the deleted electrolyte can be recharged with sodium chloride brine instead of salt (simplifying the whole process). I need to finish my experimental hot cell and see if it performs as well as I hope it does. I may tailor down the size for a "proof of concept" cell first, before scaling up the scope of a small production cell. If I can get a steady production of high purity sodium chlorate crystals, it will make the hobbyist production of high purity potassium perchlorate a practical reality. A challenging but fun prospect. WSM Edited February 11, 2018 by WSM Link to comment Share on other sites More sharing options...
WSM Posted February 11, 2018 Share Posted February 11, 2018 (edited) That does sound very complicated, I'd like to keep things a simple as possible so perhaps I'll forget the whole salt basket idea for now. By all means, keep things simple till you get comfortable with the processes and challenges. I wouldn't give up on the salt basket idea, though. In future projects, it may be just what's needed to make your system more well-suited to your needs. I recall Swede using such a system with some of his more advanced setups. Good luck. WSM Edited February 11, 2018 by WSM Link to comment Share on other sites More sharing options...
Simoski Posted February 18, 2018 Share Posted February 18, 2018 (edited) Potential New Anode Material for making (per)chlorates... lanthinum hexaboride LaB6, any chemists out there... will it work? To my mind it will cos it's used in high temperature applications, does not oxidise and is highly conductive. used in electron microscopes/ high temp refractory applications Look herehttps//youtu.be/1xF6jlcQ_m8 Edited February 20, 2018 by Simoski Link to comment Share on other sites More sharing options...
Pyrophury Posted February 18, 2018 Share Posted February 18, 2018 Made 4 Ti brackets to hold my second cathode plate. They're 36mm long and 12mm wide, which should give me 15mm space between electrodes. This is about as close as I can go as I didn't off-set the straps. I don't want to spot weld them yet though, as I haven't got my compression fittings yet. I filled the tubes with 50:50 tin/lead solder after giving the insides of the tube a good going over with a round file, then drilled and tapped 20mm x 6mm holes by hand and sanded down the ends, before inserting the threaded rod (sharpened to a point) and tightening them up as hard as possible. I think they look pretty good with these brass thumb nuts. 16mm2 cable might be overkill. Also got my power supply and meters sorted, it's a 5v 60A. Did a quick test and it's doing better than my lab supply. I'm getting up to 5A when I bring the electrodes about 20mm apart and that's at just 19oC. I've noticed a lot of black flecks in my brine from the first test, I think my cheap lab supply must have stripped off some of the oxide layer from my anode, damage doesn't look too bad though. 1 Link to comment Share on other sites More sharing options...
memo Posted February 18, 2018 Share Posted February 18, 2018 nice Link to comment Share on other sites More sharing options...
Pyrophury Posted February 24, 2018 Share Posted February 24, 2018 Still waiting on my compression fittings, but I went ahead and spot welded the cathode plates together anyway... I'm going to make a lid out of PVC sheet for this 5mm thick glass vase, which is 300x180mm. Link to comment Share on other sites More sharing options...
WSM Posted February 25, 2018 Share Posted February 25, 2018 Made 4 Ti brackets to hold my second cathode plate. They're 36mm long and 12mm wide, which should give me 15mm space between electrodes. This is about as close as I can go as I didn't off-set the straps. I don't want to spot weld them yet though, as I haven't got my compression fittings yet.I filled the tubes with 50:50 tin/lead solder after giving the insides of the tube a good going over with a round file, then drilled and tapped 20mm x 6mm holes by hand and sanded down the ends, before inserting the threaded rod (sharpened to a point) and tightening them up as hard as possible. I think they look pretty good with these brass thumb nuts. 16mm2 cable might be overkill. Also got my power supply and meters sorted, it's a 5v 60A.Did a quick test and it's doing better than my lab supply. I'm getting up to 5A when I bring the electrodes about 20mm apart and that's at just 19oC.I've noticed a lot of black flecks in my brine from the first test, I think my cheap lab supply must have stripped off some of the oxide layer from my anode, damage doesn't look too bad though. So far, it looks like a very clean setup and if everything works well together, it should do very nicely. WSM Link to comment Share on other sites More sharing options...
WSM Posted February 25, 2018 Share Posted February 25, 2018 (edited) Still waiting on my compression fittings, but I went ahead and spot welded the cathode plates together anyway... I'm going to make a lid out of PVC sheet for this 5mm thick glass vase, which is 300x180mm. Your cell looks good. I would suggest using thicker PVC plate for the lid unless you are using a compatible polymer nut on the inside end of the threads of the compression fittings. I like to use 9mm to 13mm thick (or thicker) PVC plate for the cell lid so I can drill and tap it for the compression fittings I use. By the way, for the compression fittings, my preference is to use fluoropolymers such as PTFE (expensive) or PVDF which will withstand many chemical environments and greater temperatures than most of the common plastic materials available. The trick in drilling thick PVC plate is to not use regular HHS drills made for metal (the flutes are too aggressive for hard polymers), which will catch and bind the plastic, causing it to break or tear. I've found that Forstner bits (or even spade bits, if carefully controlled) can do an excellent job of making a clean hole in the hard PVC polymer. I've also used step drills, but a "stepless" version (if you can find one) works even better for thicker material. Be sure to back the plate up with a sacrificial wood plank so the polymer is properly supported during the drilling step, and don't use too much speed or pressure (just let the bit cut at a comfortable rate). After the hole is prepared; I use clean, sharp plumbing taps to thread the hole to accept the compression fittings that are sized to accept the outside diameter of the titanium leads. I often have to modify the compression fittings by carefully drilling out the step designed to stop the tube, thus allowing the round rod to pass through and seal when tightened by the compression nut. I like to use a minimum of three wraps of Teflon plumber's tape on the threads of the compression fittings for a good seal, preventing salt creep (a pet peeve of mine), which damages the electrical connections. Have fun. It's nice to see someone do such nice work. WSM Edited February 25, 2018 by WSM Link to comment Share on other sites More sharing options...
WSM Posted February 25, 2018 Share Posted February 25, 2018 (edited) nice Yes, very nice indeed! (Swede would be so proud! ) I especially like the prefab bus bars. They look so much cleaner than fabricating them by hand from copper bar stock. WSM Edited February 25, 2018 by WSM Link to comment Share on other sites More sharing options...
WSM Posted February 25, 2018 Share Posted February 25, 2018 (edited) The size of the cell reaction vessel (RC) will determine the speed of the total reaction, depending on the size and current draw of your electrodes. It can get a little complicated, but don't worry about that. Just run it and see how it goes... Oops! That should have read "reaction chamber (RC)". Sometimes I'm too quick with the Send button and too slow with the Edit button . WSM Edited February 26, 2018 by WSM Link to comment Share on other sites More sharing options...
Pyrophury Posted February 25, 2018 Share Posted February 25, 2018 Your cell looks good. I would suggest using thicker PVC plate for the lid unless you are using a compatible polymer nut on the inside end of the threads of the compression fittings. I like to use 9mm to 13mm thick (or thicker) PVC plate for the cell lid so I can drill and tap it for the compression fittings I use. By the way, for the compression fittings, my preference is to use fluoropolymers such as PTFE (expensive) or PVDF which will withstand many chemical environments and greater temperatures than most of the common plastic materials available. Thanks! I was thinking of cutting discs from the PVC sheet and then solvent welding them together, so that way I have a lip and can try fitting a viton O ring. I would have liked to have gone with PVDF fittings, but of the few suppliers I found that have them here, they were just way too expensive. So I'll have to settle for Polypropylene (if they ever arrive). The trick in drilling thick PVC plate is to not use regular HHS drills made for metal (the flutes are too aggressive for hard polymers), which will catch and bind the plastic, causing it to break or tear. I've found that Forstner bits (or even spade bits, if carefully controlled) can do an excellent job of making a clean hole in the hard PVC polymer. I've also used step drills, but a "stepless" version (if you can find one) works even better for thicker material. Be sure to back the plate up with a sacrificial wood plank so the polymer is properly supported during the drilling step, and don't use too much speed or pressure (just let the bit cut at a comfortable rate). After the hole is prepared; I use clean, sharp plumbing taps to thread the hole to accept the compression fittings that are sized to accept the outside diameter of the titanium leads. I often have to modify the compression fittings by carefully drilling out the step designed to stop the tube, thus allowing the round rod to pass through and seal when tightened by the compression nut. Thanks for the advice, I'm sure it'll come in very handy. Link to comment Share on other sites More sharing options...
Arthur Posted February 25, 2018 Share Posted February 25, 2018 In the UK the stepless step drill would be called a cone drill or a taper drill. In the USA who knows (Ace Hardware doesn't) Link to comment Share on other sites More sharing options...
WSM Posted February 26, 2018 Share Posted February 26, 2018 (edited) Thanks!I was thinking of cutting discs from the PVC sheet and then solvent welding them together, so that way I have a lip and can try fitting a viton O ring. I would have liked to have gone with PVDF fittings, but of the few suppliers I found that have them here, they were just way too expensive. So I'll have to settle for Polypropylene (if they ever arrive). Thanks for the advice, I'm sure it'll come in very handy. See if an ozone supplies company* exists in Europe. If so, they may handle PVDF compression fittings. The other type company to handle PVDF fittings in the US is U.S.Plastics Company in Ohio. I have no idea what is available in Europe. Good luck with your search. WSM Edit - *Ozone generators are used in the US in conjunction with short wave UV lamps to purify water (besides other techniques, i.e. filtering). Edited March 4, 2018 by WSM Link to comment Share on other sites More sharing options...
WSM Posted February 26, 2018 Share Posted February 26, 2018 (edited) In the UK the stepless step drill would be called a cone drill or a taper drill. In the USA who knows (Ace Hardware doesn't) Harbor Freight Tools does has them. I don't recall exactly what they call them, though. A search through their online catalog in the "drill bit" section may reveal the name used. WSM Edited March 4, 2018 by WSM Link to comment Share on other sites More sharing options...
Pyrophury Posted March 4, 2018 Share Posted March 4, 2018 Didn't get much done this weekend, it's been so cold... I just cut the rough shape of my RC lid from sheets of 5 and 10mm thick PVC. Link to comment Share on other sites More sharing options...
WSM Posted March 21, 2018 Share Posted March 21, 2018 (edited) Didn't get much done this weekend, it's been so cold... I just cut the rough shape of my RC lid from sheets of 5 and 10mm thick PVC. Hi Pyrophury, That's a nice looking lid. If you make another one, You may want to try making it overhang the OD of the tank so it's easier to remove when you want or need to. My 2 cents. WSM Edited March 21, 2018 by WSM Link to comment Share on other sites More sharing options...
eb666 Posted April 16, 2018 Share Posted April 16, 2018 On 12 august 2017 I posted about a platinum anode.I cannot post details here as the board will not allow me to post zip files!!! See sciencemadness.org 'thoughts on anodes' in the 'Technochemistry' section if interested. The anode works great and will give kg and kg of perc of used correctly. I subjected the Pt to abusive conditions and it held up well. About 60 dollars will get you a one gram bar. It will make around 140 grams perc from chlorate per day at 3 amps EB Link to comment Share on other sites More sharing options...
Arthur Posted April 16, 2018 Share Posted April 16, 2018 Platinum is one of the long established electrode metals, it simply works. However to get a decent surface area usually costs a lot. I've just found 10mm x 50mm x 1mm for about £350, then you need the connector wire and it's still only 10 cm2 which will not take much current for the money. The issue with platinum is that it erodes significantly if abused by over current. Someone used a platinum wire as an electrode most currents were too much because of the small surface area. The platinum eroded next to the holder til it dropped off and fell to the bottom. One reported commercial method used platinum sheet as electrodes which worked well but there was the massive investment to pay for and the cost of erosion losses measured in grammes per ton of product. Does anyone want to evaluate the cost of running a platinum electrode vs the cost of using a lead dioxide electrode or any other. Link to comment Share on other sites More sharing options...
WSM Posted April 22, 2018 Share Posted April 22, 2018 (edited) Platinum does work and work well. Cost is the main issue. Fortunately, the working portion of the electrode is the surface. This means that platinum plated electrodes work as well as solid platinum, so long as the plating lasts. Proper treatment of the platinum electrode will insure longer life and higher productivity from it. My best guess to date has been to (successfully) run my platinum plated titanium electrodes "lightly", meaning at less than maximum current carrying capacity, and only for the required amount of time. Also, I use platinized titanium (or LD) electrodes exclusively for converting sodium chlorate to sodium perchlorate, preparatory to forming potassium perchlorate (or other perchlorates). I use MMO for producing chlorates and save the more specialized and expensive electrodes for better things. I've considered using platinum bullion for electrodes, but I feel the better form would be to roll the "coin" into foil and carefully spot weld it to a CP titanium frame for support. The greater surface area would allow for more workable surface of the electrode. Those are some of my thoughts on the subject. I haven't pursued it due to the expense of platinum and my success to date with the lower cost lead dioxide electrodes I've managed to acquire. I've also gotten hold of several platinized titanium mesh electrodes, and their cost is well below that of solid platinum materials. These are my opinions; your mileage may vary... WSM Edited April 22, 2018 by WSM Link to comment Share on other sites More sharing options...
Pyrophury Posted April 29, 2018 Share Posted April 29, 2018 (edited) It's getting there, slowly... I made a Viton rubber o-ring and groove for it to sit in, and tapped the holes for the 3/8" NPT compression fittings. Edited April 29, 2018 by Pyrophury Link to comment Share on other sites More sharing options...
WSM Posted April 30, 2018 Share Posted April 30, 2018 It's getting there, slowly... I made a Viton rubber o-ring and groove for it to sit in, and tapped the holes for the 3/8" NPT compression fittings. Good work. It looks like it's coming along nicely. WSM Link to comment Share on other sites More sharing options...
WSM Posted July 1, 2018 Share Posted July 1, 2018 (edited) As I've put my high temperature sodium chlorate cell experiment on hold due to my failure to get a liquid tight seal on my fabricated cell, I've considered miniaturizing an experimental setup for a "proof of concept", before continuing on the larger cell. This was briefly mentioned in the original patent, but no results were mentioned. For this effort, I've managed to acquire a round bottomed, borosilicate 5 liter reaction flask without a lid, for a reasonable cost. The large diameter, top flange of the heavy walled container has a groove to accommodate an O-ring (which I plan to fabricate from Viton tubing) and I'll use a thick polymer plate for the cell lid (which can be modified to hold the electrodes and various fittings for vents and sensors) and seal it to prevent salt-creep. As the goal is to run the cell at approximately 110oC, so it will naturally concentrate the NaClO3 by evaporation of the water as the cell runs, I'll run the current as high as possible to the electrodes and monitor the temperature carefully. If the electrodes aren't enough alone to heat the cell that high, I have heating mantles that can be used to boost the temperature, if required. I hope to set this experiment up by September at the latest, to test the system and verify what the patent declares. WSM Edited July 2, 2018 by WSM Link to comment Share on other sites More sharing options...
WSM Posted July 5, 2018 Share Posted July 5, 2018 Happy Fourth of July to all the US readers here. Be safe tonight, as you celebrate our nation's 242nd birthday. WSM Link to comment Share on other sites More sharing options...
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