Delays, delays, delays...
Entry posted by Swede
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I would have imagined long ago that I would have made a lead dioxide plating attempt by now, but the more I read, the more useful information that I am able to gather... and the more reagents and hardware I seem to require. The print resources and other descriptions are rarely simple "home chemist" solutions. Usually, they are patents, and the patent office is not going to award a new patent to a scientist who plates a tiny MMO anode in a 1 liter beaker - they are going for the biggest, best, new methods known to mankind. The patent setups, without exception, are elaborate, and not something that is easily replicated in an amateur shop. No luck at all in finding a mythical "anode in a beaker" patent or description. The complicated setups "call" to me - I am an addict for complexity - but if the goal is a simple setup that anyone can replicate, then I need to be a bit more selective.
I realize that my setup, as it exists, is not simple. But KISS is not always the best answer in chemistry and other industrial processes. My primary initial goal is a successful anode, and my efforts tend to evolve towards complexity. The secondary goal for the future will be to simplify, and make the setup easy to replicate, without losing strength and functionality of the anode. Simplicity, and ease of replication, are useless unless the anode can withstand the rigours of a perchlorate cell and actually make perchlorate without falling apart.
A lot of the work in the last three weeks has gone into hardware. Something as simple at securing a cathode in a stable and repeatable manner requires some effort. Selection of materials. Preparation of the multiple power supplies used to plate, vibrate, heat, and rotate. Gathering the necessary reagents. To execute the plating in a manner consistent with the tons of research I've pursued (weeks worth) requires, unfortunately, a lot of gadgets. I keep finding myself making more and more stuff.
Well, I was hoping to plate today... and I ran out of time. It's Saturday, I have a spouse, and that = chores. I wanted to show you guys where I was at.
First, the plating rig overall:
I've shown portions of this beast before. It has a gear-motor driven anode spinder using a copper rod as a rotating shaft. I incorporated a vibrator motor, a fairly hefty one, and during a preliminary run with water today, I discovered something quite interesting. Even without the anode immersed in the solution, there was a powerful agitation factor as the vibrations traveled through the rig, the stand, and into the solution. With the motor at maybe 15%, the agitation was noticeable. At higher motor settings, I could literally blow the water out of the tank. If there was lead nitrate in the tank, it would have made a dangerous mess. Also at higher settings, there was a tendency for the plating tank to move relative to the rig, and this is a bad notion, as the anode may make contact with the cathode, or hit the side walls of the vessel. The last thing I want to do is turn this thing into an ultrasonic cleaner! It could end up stripping lead dioxide as fast as it could form! I made the weight on the motor adjustable, and I believe the best setting is low frequency, large amplitude, as if a researcher was literally waving the anode gently in the solution.
In this picture, I am using a 2 liter plastic tank. Check out the surface of the water!
The first runs are going to be 2 liters, rather than the 5 or 6 liters consumed by the polypropylene tank, IF the thin and cheap plastic shown here can withstand 70 degrees without weakening significantly. Note that I have a large gray "catch-pan" in case of catastrophic failure. The pan should contain any spills with no problems. Not seen behind the whole setup is a cheap HEPA air filter. If drops of the bath become aerosolized, hopefully they will bet trapped in the HEPA filter where they will dry and accumulate. I have visions of lead nitrate settling like a fine, toxic dust everywhere. Not good.
There are two things I ignored that I need to accomplish before I can plate. The first is cathode(s). I need more than one, because I will be plating anodes of different sizes, and this, of course, requires different cathode sizes as well. With my acquisition of Ti tube, anybody see any problems using Ti as a cathode? The round tube is perfectly shaped for a rotating setup. I have tubing in 3/4", 1/2", and 5/16", and am considering "squashing" the working end in a press to create an ovoid shape, again to create an even flux with the rotating anode. A hole drilled in the upper portion of the cathode will accept the cathode power wire.
When the cathodes are made, I need a way to firmly attach them mechanically to the system. They must be physically secured, considering the movement this thing generates. Spacing (anode to cathode) will be adjusted by the simple expedient of moving the tank closer or farther as needed.
I anticipate the addition of 5 grams of PbO per liter per hour to control nitric acid buildup, and to replenish the Pb ion concentration. By using some of the thousands of tiny sample bottles I have collected over the years, I prepared a number of individual 5 gram samples of PbO. These will be used to add the PbO, then capped, and disposed of with the remainder of the toxic waste.
A while back, I ordered a "teflon coated scoop from some science supply house, and the teflon peeled right off the scoop when I used it to gently stir a solution! What a POS. Anything teflon coated should be able to handle such a simpe chore without problems. A bit disgusted, I made some scoops out of solid PTFE, and these have the benefit of being easy to clean... they slide right into a test tube, and concentrated nitric (or other acid) is added. Anything clinging to the scoops is dissolved, and no harm comes to the PTFE!
http://www.5bears.com/chem1/scoops04.jpg
I will admit working with the lead salts is a bit scary, but really, it is no big deal. Lay down a big sheet of paper, wear a respirator, plenty of hand washing, and wear gloves, of course, because spills are inevitable:
Note the loose PbO on the paper. It is best to use some sort of disposable working sheet in cases like this to avoid polluting a workbench surface.
Time to clean the scoop thoroughly! I would not be doing this for 98% of the chems I use, but for lead compounds... yes.
I am currently in in the process of rebottling and relabeling ALL of my chemicals, as I had mentioned in a separate thread.. The prime reason is I like the chems to be in a poly bag, rather than loose. Secondly, if I am "raided", the hopefully professional appearance of my lab will look good in court! Third, I like the consistency. I found a source of inexpensive HDPE bottles with screw lids that STACK with plenty of stability. Since space is at a premium, that is helpful. Some of the bottles came with orange caps; the majority were white. Those with orange caps are reserved for the more dangerous chems.
I also still need to rig up my bell jar if I want to attempt to vacuum the anodes prior to plating, and I may as well do so, since it'll be no big deal, and may help the plating process.
So, hopefully, Tuesday. We'll see! 
Wish me luck!
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