OldMarine Posted July 6, 2016 Posted July 6, 2016 I guess I'd better not mention the chemicals!They sell equipment for water/wastewater treatment so I should have known they sold testing equipment as well.
WSM Posted July 7, 2016 Posted July 7, 2016 I guess I'd better not mention the chemicals!They sell equipment for water/wastewater treatment so I should have known they sold testing equipment as well. Wait! They got chemicals?!! Now you've GOT to take pictures. Do they mail order? Gimme, gimme, gimme!!! Hey man, help a brother out. Seriously, though; you've piqued my interest, plus I'm curious to know more. Thanks. WSM
WSM Posted July 7, 2016 Posted July 7, 2016 That wasn't what he wrote, WSM! <G>Lloyd??? Did I misunderstand him? They also sell chemicals is what I understood. I'm just curious which chemicals they carry. WSM
WSM Posted July 8, 2016 Posted July 8, 2016 (edited) I learned a valuable lesson with the sodium chlorate experiment. It's important to not replace the withdrawn samples or harvesting portions with brine (sodium chloride solution). When the removed portions are replaced with brine, the brine dilutes the mother liquor and drives it toward the liquid phase, so less chlorate can be dropped out. This problem is avoided if you add solid NaCl instead; because the solid crystals don't drive the liquor toward the liquid phase, but leave it where more solid chlorate can crystallize, but as the chloride is dissolved, it stays in solution and is consumed. This will be clearer when I can show the modified sodium chlorate chart accompanied with a detailed description. Again, more to come... WSM Edited July 8, 2016 by WSM
WSM Posted July 8, 2016 Posted July 8, 2016 (edited) I harvested another batch of "jewels" this evening. After three full days, I got a smaller crop but some are truly beautiful: And one huge imperfect crystal; the largest to date, measuring roughly 17 mm x 16 mm: I started another jar full of electrolyte and we'll see how it does in a few days. I measured the volume of the PET jars and they're one gallon (3.785 liters) and I'm filling them nearly full of electrolyte before putting them in the cooler. Still more to come... WSM Edited July 8, 2016 by WSM
Arthur Posted July 8, 2016 Posted July 8, 2016 The chlorate that you remove needs to be replaced with 0.547 x its weight with fresh chloride to maintain the chloride concentration in the cell Mol wt chloride / mol wt chlorate 58/106 = 0.547 The only other way is to get the liquor so hot that it loses water and can accept brine going in.
WSM Posted July 8, 2016 Posted July 8, 2016 (edited) The chlorate that you remove needs to be replaced with 0.547 x its weight with fresh chloride to maintain the chloride concentration in the cellMol wt chloride / mol wt chlorate 58/106 = 0.547The only other way is to get the liquor so hot that it loses water and can accept brine going in. Thanks for the numbers. I appreciate you taking the time to figure them out and write it here. I don't think my chlorate concentration has reached its maximum level at the current temperature, yet. The system is still running and I'm still adding dry NaCl crystals periodically. I haven't gotten things balanced quite yet, but I'm getting closer. It's my opinion that your numbers will work perfectly as a minimum amount of chloride crystals, and that more is okay. I believe this is true because the dry crystals won't dilute the dissolved chlorate concentration and maybe take longer to force the chlorate to the point where it can "salt out". Once the chlorate concentration reaches saturation (for its given temperature), then the minimum will be enough to maintain the concentration. WSM Edited July 8, 2016 by WSM
WSM Posted July 8, 2016 Posted July 8, 2016 (edited) I call this mineral Sodiumchloratealite Not bad. They do have that certain 'mineral' look. Some of the crystals that form on the wall of the jar (separate from the main mass on the bottom) grow to a single beautifully clear crystal, and look like a mineral sample. WSM Edited July 8, 2016 by WSM
WSM Posted July 8, 2016 Posted July 8, 2016 Before the end of the month, I hope to add a pH control system to the cell and start to get it calibrated to drive the pH as close as possible to 6.8 without "overdriving" it to below 6.1 where, I'm afraid it'll start pumping free chlorine out ! I need to set up the pH control system so I can just switch it on when it's the right time to start. We'll see... WSM 1
TomasBrod Posted July 9, 2016 Posted July 9, 2016 You mentoin the cristals, yes they are nice. I tried to grow a larger crystal on a string but got only to ~7mm.If you inspect them from one side they look cubic, but on the other side there isa beveled vertex and three beveled edges (parts of a cube) it is amazing.Some crystals have the vertex chipped so much, that no longer like cube and some don't have beveled edges.Have you found yet an official doc on the crystal structure of sodium chlorate?
WSM Posted July 9, 2016 Posted July 9, 2016 (edited) You mentoin the cristals, yes they are nice. I tried to grow a larger crystal on a string but got only to ~7mm.If you inspect them from one side they look cubic, but on the other side there isa beveled vertex and three beveled edges (parts of a cube) it is amazing.Some crystals have the vertex chipped so much, that no longer like cube and some don't have beveled edges.Have you found yet an official doc on the crystal structure of sodium chlorate? I see the same differing shapes you describe. They are simply beautiful. I think there are myriad various shapes possible, but with the sodium chlorate crystals I'm seeing that they're fundamentally cubic, even though they exhibit multiple variations (or portions) of cubes. What I'm doing to harvest the larger crystals is taking large samples (>3.5 liters), put them in a clear one gallon PET jar with a lid and place the jar of hot electrolyte in a refrigerator running at 0oC to 5oC and leave it undisturbed (don't touch the jar at all) for 48-72 hours. Next I harvest the crystals by decanting the depleted liquor and then dumping the moist crystals onto a sheet of large lab grade filter paper which is on top of folded paper towels on a glass dinner plate, to absorb the moisture clinging to the crystals. I dry them, covered with a paper towel, for several days and carefully break the clumped crystals apart as they air-dry. The best crystals I've gotten so far (the clearest) are those that grow on the side of the jar, by themselves, and not in the mass of crystals on the bottom of the jar. I've been fascinated by what they look like. WSM Edit:1) To answer the question, "Have you found yet an official doc on the crystal structure of sodium chlorate?"; No I haven't. There are clues in various reference books and articles, but I haven't found anything definitive yet. 2) Another thing I've done is use high purity starting materials. I purified the water softener salt by dissolving it in distilled water, decanting the clear brine away from sediment and larger contaminants (large chunks of rust and stones), and then treating the clear brine with a small portion of sodium carbonate solution, which dropped out magnesium and calcium ions. I vacuum filtered the brine to remove all the sediments, neutralized the alkalinity with HCl and then started my cell. It sounds like a lot of bother, but my results are a purer end product. This is my first time doing any of this and I wanted to get as pure a results as possible. Edited July 10, 2016 by WSM
taiwanluthiers Posted July 9, 2016 Posted July 9, 2016 Why not just use non iodized table salt? they would be very pure. I wonder if you could grow explosive crystals by somehow mixing a fuel into the crystal matrix...
WSM Posted July 9, 2016 Posted July 9, 2016 (edited) Why not just use non iodized table salt? they would be very pure.I wonder if you could grow explosive crystals by somehow mixing a fuel into the crystal matrix...Since the human body needs both magnesium and calcium, I doubt they'd bother removing those minerals from table salt. Also, they tend to add free-flow agents and sodium ferrocyanide to table salt. If I have to purify it anyway, I may as well start with the cheapest, plain-jane water softener salt I can find. WSM Edited July 10, 2016 by WSM
OldMarine Posted July 9, 2016 Posted July 9, 2016 Common table salt is basically Halite which has calcium and magnesium as it's secondary ingredients. The only difference usually between that and softener grade is the insoluble material content. Learned this at a water softener seminar I attended in January. Never thought it would relate to pyro in any way! Funny how that works.
Kevin Posted July 9, 2016 Posted July 9, 2016 Hi, I'm working on making my making my first titanium electrodes. I'm planning to use titanium tubing spot welded onto titanium sheet/ MMO mesh. I was just heating up and compressing the tubing (in a hydraulic press) to make a flat end for spot welding. No bubbles were formed when blowing into it by mouth into a pail of water, however I tested it with an air compressor and bubbles came through even after several heating and pressing cycles. My plan is to fill the tubing with copper wire and melt in lead free solder. Should I be concerned about the bubbles making it through or does this sound sufficient to move on to spot welding the electrodes? Kevin
Mumbles Posted July 9, 2016 Posted July 9, 2016 ...Have you found yet an official doc on the crystal structure of sodium chlorate? ...1) To answer the question, "Have you found yet an official doc on the crystal structure of sodium chlorate?"; No I haven't. There are clues in various reference books and articles, but I haven't found anything definitive yet. ... I'd be happy to provide you guys with crystal structures of sodium chlorate or whatever else you want. I'm not sure exactly what you hope to gain from that information though. ...I wonder if you could grow explosive crystals by somehow mixing a fuel into the crystal matrix... Possible, but irrelevant to the conversation.
WSM Posted July 9, 2016 Posted July 9, 2016 (edited) Hi, I'm working on making my making my first titanium electrodes. I'm planning to use titanium tubing spot welded onto titanium sheet/ MMO mesh. I was just heating up and compressing the tubing (in a hydraulic press) to make a flat end for spot welding. No bubbles were formed when blowing into it by mouth into a pail of water, however I tested it with an air compressor and bubbles came through even after several heating and pressing cycles. My plan is to fill the tubing with copper wire and melt in lead free solder. Should I be concerned about the bubbles making it through or does this sound sufficient to move on to spot welding the electrodes? Kevin Hi Kevin, If no bubbles come through with blowing, it sounds good enough. I've had very good luck by that standard so far. If you're concerned, spot weld a row of welds across the pressed end of the tube and then proceed as usual. I've had varying results depending on the wall thickness of the titanium tubing, so I have to ask what the wall thickness of your tubing is? My best results were with thicker walled tubing. Good luck with your project; it sounds like you've got a good handle on it. WSM Edited July 10, 2016 by WSM
WSM Posted July 9, 2016 Posted July 9, 2016 I'd be happy to provide you guys with crystal structures of sodium chlorate or whatever else you want. I'm not sure exactly what you hope to gain from that information though. I believe we're trying to understand the apparent difference between the written descriptions online and what we're seeing as our crystals form. From the written descriptions, I'd almost have expected a collection of salient cubes, but what we're seeing is more like parts of cubes from various angles and divisions all agglomerated together. They're not what I envisioned, but I'm not disappointed either. Thanks for the offer. I appreciate any help on the subject. WSM
Mumbles Posted July 10, 2016 Posted July 10, 2016 Finally, somewhere I can actually contribute meaningfully. There are two major crystallographic databases. There's the Crystallographic Open Database, which as it sounds is open access. http://www.crystallography.net/ Then there is the more thorough Cambridge Crystallographic Structural Database http://www.ccdc.cam.ac.uk/solutions/csd-system/components/csd/ The CSD is bigger (ca. 800,000 vs 100,000 entries), but also is difficult to access without University access. You can technically get any structure they have for free, but you need to know the CSD refcode or deposition number or the journal Digital Object Identifier (DOI). You can't search by formula, structure, etc. without a subscription. It is true that sodium chlorate crystallizes in a cubic space group. It specifically crystallizes is the P213 space group, which is a primitive cubic structure. Interestingly, despite being an achiral molecule the P213 space group is a chiral space group. If you looked at your crystals through a microscope with polarized light, you'd see distinct left and right handed crystals, and there would be about equal amounts of both. http://www.homepages.ed.ac.uk/aalexand/chlorate.html This may actually be a part of what you're seeing. More that likely what you guys are actually observing is imperfect crystal growth and a phenomenon called twinning. This is when two crystals of the same compound grow together but offset from one another. As an occasional x-ray crystallographer, it is also the bane of my existence from time to time. Sometimes it can be simple like a cube growing off of a cube. Sometimes it's more complicated, like two intertwined cubes that look more like a star. Sometimes the two crystals are mirror images of one another, or offset slightly from one another. There can be dozens of individual crystal domains all growing as one giving rise to very interesting looking structures. None of this has any influence on purity or composition, just gives rise to interesting morphologies and has an influence on some optical properties. Chiral compounds and crystals tend be more likely to twin in my experience. Crystals are selective toward one handedness based on how they pack together. If both handednesses are seeded from the same area, you can grow a co-crystal containing both pairs, but with domains comprised of essentially pure left and right handed parts. Check out some of the pictures of twinned cubic crystals, and see if anything looks familiar. https://www.google.com/search?q=twinned+cubic+crystals 1
WSM Posted July 10, 2016 Posted July 10, 2016 (edited) Finally, somewhere I can actually contribute meaningfully. There are two major crystallographic databases. There's the Crystallographic Open Database, which as it sounds is open access. http://www.crystallography.net/ Then there is the more thorough Cambridge Crystallographic Structural Database http://www.ccdc.cam.ac.uk/solutions/csd-system/components/csd/ The CSD is bigger (ca. 800,000 vs 100,000 entries), but also is difficult to access without University access. You can technically get any structure they have for free, but you need to know the CSD refcode or deposition number or the journal Digital Object Identifier (DOI). You can't search by formula, structure, etc. without a subscription.It is true that sodium chlorate crystallizes in a cubic space group. It specifically crystallizes is the P213 space group, which is a primitive cubic structure. Interestingly, despite being an achiral molecule the P213 space group is a chiral space group. If you looked at your crystals through a microscope with polarized light, you'd see distinct left and right handed crystals, and there would be about equal amounts of both. http://www.homepages.ed.ac.uk/aalexand/chlorate.html This may actually be a part of what you're seeing.More that likely what you guys are actually observing is imperfect crystal growth and a phenomenon called twinning. This is when two crystals of the same compound grow together but offset from one another. As an occasional x-ray crystallographer, it is also the bane of my existence from time to time. Sometimes it can be simple like a cube growing off of a cube. Sometimes it's more complicated, like two intertwined cubes that look more like a star. Sometimes the two crystals are mirror images of one another, or offset slightly from one another. There can be dozens of individual crystal domains all growing as one giving rise to very interesting looking structures. None of this has any influence on purity or composition, just gives rise to interesting morphologies and has an influence on some optical properties. Chiral compounds and crystals tend be more likely to twin in my experience. Crystals are selective toward one handedness based on how they pack together. If both handednesses are seeded from the same area, you can grow a co-crystal containing both pairs, but with domains comprised of essentially pure left and right handed parts. Check out some of the pictures of twinned cubic crystals, and see if anything looks familiar. https://www.google.com/search?q=twinned+cubic+crystals Very nice! Thank you, Mumbles. May I quote you? WSM Edit: I definitely see lots of twinning in my sodium chlorate crystals. Edited July 10, 2016 by WSM
Kevin Posted July 10, 2016 Posted July 10, 2016 Hi Kevin, If no bubbles come through with blowing, it sounds good enough. I've had very good luck by that standard so far. If you're concerned, spot weld a row of welds across the pressed end of the tube and then proceed as usual. I've had varying results depending on the wall thickness of the titanium tubing, so I have to ask what the wall thickness of your tubing is? My best results were with thicker walled tubing. Good luck with your project; it sounds like you've got a good handle on it. WSM The tubing's wall thickness is 0.035" thick and has an outside diameter of 1/4". Thanks, I'm looking forward to producing a clean product with no graphite dust in it! Kevin
WSM Posted July 11, 2016 Posted July 11, 2016 The tubing's wall thickness is 0.035" thick and has an outside diameter of 1/4". Thanks, I'm looking forward to producing a clean product with no graphite dust in it!Kevin What size is your proposed anode? If it's too big the tubular titanium will get extremely hot, possibly damaging the compression fittings. Our friend, pyrojig had this happen with his bucket cell a couple years ago and the fix to the problem was to use larger diameter CP titanium tubing, filled with pure, solid copper (like what I'm using in the sodium chlorate cell). His anode was 1" x 6.75" (the current demand was about 26 Amps) and we used 6mm OD x 4mm ID CP tubular titanium leads. They were filled with lead-free solder (95% tin) and the top end was threaded with a 10-32 tap and the electrical connection was a ring terminal on the power leads. The leads got so hot that the PVDF compression fittings were negatively affected. They held but were damaged by the heat. Stepping up to 3/8" OD tubing with 0.042" wall thickness, tapped with 5/16-18 threads, and filling the tube with a 1/4" solid copper rod works and has kept the heat to within tolerable limits (running up to 53 Amps). WSM
Kevin Posted July 11, 2016 Posted July 11, 2016 What size is your proposed anode? If it's too big the tubular titanium will get extremely hot, possibly damaging the compression fittings. Our friend, pyrojig had this happen with his bucket cell a couple years ago and the fix to the problem was to use larger diameter CP titanium tubing, filled with pure, solid copper (like what I'm using in the sodium chlorate cell). His anode was 1" x 6.75" (the current demand was about 26 Amps) and we used 6mm OD x 4mm ID CP tubular titanium leads. They were filled with lead-free solder (95% tin) and the top end was threaded with a 10-32 tap and the electrical connection was a ring terminal on the power leads. The leads got so hot that the PVDF compression fittings were negatively affected. They held but were damaged by the heat. Stepping up to 3/8" OD tubing with 0.042" wall thickness, tapped with 5/16-18 threads, and filling the tube with a 1/4" solid copper rod works and has kept the heat to within tolerable limits (running up to 53 Amps). WSM I'm planning to use a 1" x 5" anode with two titanium cathodes starting at approximately 18 amps and run until the current drops to about 9 amps. I really like the looks of your threaded electrodes, however I'm planning to cast/ machine small aluminum blocks into which I can drill and tap two holes for bolts. The bolts will be used to fix the unit on the titanium tubing and to squish the copper wire in the electrode to the wire from the power supply- hopefully resulting in extremely low resistance. I do have 3/8" and 1/2" tubing on hand as well which I'm hoping to save for my eventual scale-up to a larger chlorate cell and hopefully someday a perchlorate cell. Kevin
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