2007-12-22
Various Pictures
With the addition of the comment system, I've been getting a lot of pyro-related messages. Having previously promised to write up the electrolysis experiments that I did beyond the first few documented here, I decided to actually do it at long last.
Unfortunately it has been years since I did these experiments, and some of the details now escape me. So, all I can present is some pictures and a few brief descriptions of what they represent.
Here is my first ultra-pure Potassium Chlorate batch, approximately 150 g. It was produced using graphite electrodes, running about 5 amps, with fertiliser-grade Potassium Chloride as the feedstock. Two cycles of purification were used. I was extremely proud of this batch, as it represented the first entirely homebrew oxidiser capable of use in good colour compositions.
A small amount of high-purity Potassium Nitrate. Lovingly purified from commercial fertilizer-grade Nitre, this is a small part of a huge batch that took several days of work on and off to purify to needlessly large numbers of nines. Not strictly part of the (Per)chlorate experiments, but another pyro-oxidisier purification experiment.
Making Lead Oxides in an ill-advised experiment with lead electrodes and acidified Potassium Nitrate electrolyte. The reaction was surprisingly vigorous, accompanied with loud crackling and splattering from the anode and producing deep pitting and quite rapidly destroying the electrodes.
Electrodes from a different run, clearly showing dioxide production at the anode. I can't quite recall how I did this, but I believe it involved a fairly common chemical for the electrolyte... I managed to melt the insulation on the wiring as the cell resistance dropped significantly during the run. The dioxide coating did not work in a Perchlorate cell unfortunately, it just flaked off.
Platinum plated Titanium electrode that I have just about destroyed by running Sodium Chloride all the way to Perchlorate. The run was at only 5 amps for a keg-sized cell, it took *months*. The yield was massive however, and I still have impure Perchlorate from this run that I haven't purified. In that sense partial destruction of the anode was totally worth it. :)
Sodium Perchlorate crystallising out by evaporation. Note the leaf floating in the liquor. It blew in the window. I found crystallising Sodium Perchlorate this way quite hard, the solution tends to absorb water from the air rather than evaporating.
Making Barium Chlorate from Barium Chloride. A rather dangerous experiment to do on the kitchen window sill! The anode is a graphite art pencil. It worked for quite some time, enough to complete the run.
Potassium Chlorate yield from 1 day of gross abuse of a computer PSU and commercial MMO electrodes. Passive cooling with a large tank of water (the bathtub) made this possible. It was especially hard on the electrodes and extremely inefficient as I was running the cell from the 12 volt rail through a nichrome rheostat that was getting plenty toasty.
Larger Chlorate cell with the same kind of MMO electrodes used to make the Chlorate above. This cell was run at quite modest current and was uncooled, it took several weeks. The crystalline material at the bottom of the cell is Potassium Chloride to keep the solution saturated, sparing the anode and maintaining efficiency.
Potassium Chloride crystals growing on Potassium Chlorate crystals. This is the result of pushing to get too much Chlorate out of a fairly Chlorate-poor brine. This photo was taken with my ancient DC290 camera through the eyepiece of my stereo microscope at 40x magnification.
A bag of large Potassium Chlorate crystals, grown slowly from the modest recrystallisation batches I was doing at this point. My cells were now robust and efficient enough to make much more Chlorate than I could ever use. I concentrated on Perchlorate from this point on.
My first cell to break the 50 Ampere barrier! Later relocated to the bathtub for cooling, this cell did in a day what my other cells did in weeks. By abusing the MMO electrode I got a fair Perchlorate yield from this setup in future runs. Boiling out the cell was the major limiting factor. The PSU comes from a Bay Networks switch that was being thrown out at work, it is capable of a ridiculous 75 A at 5 Volt! You could just about weld with it, if you disabled its protection circuits. The wiring is 8 GA multistrand copper and is still getting warm enough to soften the insulation. The heating of the meter shunt actually became a problem, its paint began to smoke and burn off.
I made very little crystalline Sodium Chlorate, generally leaving it in solution in intermediate steps. This was the largest amount I ever bothered to purify.
One of many filters of partially processed Potassium Perchlorate. This particular material is from two cycles of purification and is good enough for most purposes except the finest blues for which I did as many as four cycles for one batch. You'll note the crystal sizes, Perchlorate this grainy is a sign of very slow crystalisation, which is typical of the big batches I was doing towards the end of my experiments. I gave up making it at this point, because I had amassed far more than I could foreseeably purify and use in my modest pyrotechnic experiments. My pyro experimentation started to tail-off only a few weeks later too. The challenge of making Perchlorate was lost, I had become a licensed Pyrotechnician and was doing commercial displays which somewhat burnt me out on pyro altogether.
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Parent article: Making Chlorates and Perchlorates.