The question isn't about Why; it's about Why Not? Where do all of the most trusted accounts of events in history come from? The People Who Were There. I am one of those people who learn quickest from Doing it Myself. Trying things with my own two hands. Because of this, I've been working on a STEAM project with my community college.
Here's the basics:
Deuterium is a hydrogen molecule with an extra neutron. Heavy water is water with at least one deuterium atom in it. Heavy water is used by the nuclear industry to slow down neutrons in standard uranium reactors.
My project started out as a "I wanna try THIS!" So I started collecting batteries and cutting the acid out of them.
I took apart my el-cheapo coffee maker for a handful of reasons, one being my need for standard, cheap filters, another was it didn't fit my space anymore. regardless, I dismantled it mounted it to a 2x4, and mounted that 2x4 to a piece of MDF as a base. The end result looks like this:
Then I started filtering the solutions to remove the lead and plastic particulates. The lead based sludge is primarily lead dioxide and elemental lead dust that has flaked off from the cathode and anode respectively. It took about fifteen to twenty minutes to filter each gallon. I would shake the bottle to suspend as many particles in solution so I'd spend less time cleaning out the bottles.
The spent filters are (currently) awaiting further processing, but the exposure to the concentrated acid began to break them down over a short time, the began to lose all structure after about an hour of sitting exposed to the air.
After the preliminary filtration, I would filter them again, using more than one filter in an attempt to catch all of the really small particulates captured. I'd wait till I had about 4-5 gallons before doing this so I could drop the acid right into the water cooler jug. This did collect a surprising amount of particulate.
Even with this second filtration, an off-white cloudy substance formed at the bottom of the water jug. I'm not sure what this is as of yet.
I should add here that i took a sample of this acid to school and worked on it there in a much more controlled environment. Here's the process we did for that.
We set out to extract deuterium oxide from used-car battery acid. The materials used to accomplish this were:
· 50 mL burette with Vernier flat PH sensor.
· 500mL Distillation equipment
· Willhi WH1436A Digital Temperature Controller
· ~50L used car battery acid (collected)
· ~50mL used car battery acid (neutralized)
· Dry anhydrous sodium hydroxide
· Dry powdered KHP
· Lab-grade Distilled water
We standardized our NaOH using 1.5317g of Potassium Hydrogen Phthalate (KHP), which is a common standard for titrating, in 100mL distilled water. We made five standards total, but due to the quantity of acid we are still in the process of neutralizing it.
We started out by titrating our samples using both a commercially available 0.5 M Sodium Hydroxide (NaOH) solution and a 0.491M NaOH solution that we standardized in house. We used a Vernier interface to track the pH of all of our tests. We discovered our used acid had an average Molarity of 3.7 M, and a 10 mL sample of the acid was neutralized with an average volume of 130-135 mL of our 0.451 M NaOH solution. We pre-mixed our 10 mL of acid with 10 mL of distilled water to protect our sensor.
After neutralization, we had a clear solution with a dark, cloudy, copper colored precipitate which quickly settled out of solution. We hypothesize that this precipitate is a mix of the sodium sulfate (Na₂SO₄) and lead dioxide dissolved from the battery plates prior to disassembly.
We ended up with nearly a liter of mixed distilled water. We distilled this a second time (four trials) to achieve our 6mL of deuterium oxide. We believe that we have collected a significant sample of deuterium oxide by use of a qualitative test where we froze our sample overnight, and then slowly melted it in an ice-water bath where a portion of it, presumably standard distilled water, melted and was decanted and collected. The rest of our sample stayed frozen in the bath even while the ice surrounding it continued to melt. It kept this state for well over an hour. This is the sample that we believe to have the higher concentration of heavy water.
Our results were a little difficult to see as the scale of our operation was smaller than originally planned. If scaled up to a 10 liter primary distillation apparatus, then I believe we would acquire a clearer view of the feasibility of this project.
I plan to continue neutralizing and distilling the acid I have on hand, which comes out to about 50 liters. In order to keep the cost down, I’m going to use a sodium carbonate powder and mix it in dry. The result of this reaction is slightly different in that it produces CO₂ gas as well as the salt and water from the titration.
I have built a primary distillation apparatus to give myself ample volume to discard the sodium sulfate salt that I produce. I then intend on slowly reducing the mixed water through another distillation with a setup similar to what I’ve already tried.
At the time of submission, we are searching for access to a Mass Spectrometer or NMR Spectrometer to determine the exact concentration of heavy water that we believe to have obtained.
Sources of Error I may have encountered are as follows:
• Lack of previous hard data leads to repetitive mistakes between parties.
• Coffee filters were used to remove initial particulate. They quickly broke down when exposed to the concentrated acid. There could be portions dissolved in the pre-distilled solution.
• This was a small experimental volume, and our qualitative test could be more definitive given larger volumes.
• To preserve our glassware, we did not distill salt dry, and therefore we could still have D₂O in the salt solution. For the same reason, we did not distill 2nd run dry and there could’ve been small quantities of D₂O caught in apparatus.
• There is the potential for minute salt contamination in our final product based on the quantities of distillations.
• In terms of preemptive measures, failure to clean out transportation/storage vessels adequately could’ve contaminated the final product.
• We could’ve let the secondary distillations run a bit longer to further concentrate the solution.
After determining the above results, i could continue work at home with a solid understanding under my belt. I picked up a 50 lb (25 kg) bag of sodium carbonate from the local auto parts store, where you can get it as "Battery Acid Neutralizer," how convenient. The only issue with using this instead of another base is that it produces a lot of CO2 gas as a by-product. I'm planning on capturing it for use as a shielding gas for another project.
I'm figuring on doing 6 liter (~2 gal) batches of neutralized acid in my first distillation, but that doesn't mean I'm going to do 6 liter neutralizations. I've figured out that a little over 6 kg (6.018 kg to be exact) should bring 5 gallons of acid to a neutral pH. So I've measured out 6.050 because I'm not exact when pouring from a 5 gallon water jug.
I'm currently working on a portion-control system for adding the acid directly into the carbonate, but that's not quite done yet. I'll give that a try for the next batch.
To compare this to what I've already done at school, We started with a batch of acid I'd already double filtered, but kept separate. we found that it had a Molarity of 3.7 and change. We decided the best route to do here was neutralization by 0.5M (sodium hydroxide) NaOH solution. this ended up working fine, but it would take an average of 135 ml of NaOH solution just to neutralize 10 ml of acid in a solution of 10 ml distilled water. Neutralization was met with a dark, cloudy, copper colored solution that settled on the bottom of the container fairly quickly. we hypothesize that this is a mixture of the sodium-sulfate salt produced by the reaction and a small amount of lead dioxide that has leached into solution from the battery.
As a later update: Adding acid to dry-base can cause some issues. Namely if you wait too long in between acid additions, you end up growing crystals. These are beautiful when left unattended for more than 12 hours, as they begin to grow long at this point. These clear, geometric formations that are tinted the color of solution, can be washed clean with distilled water to become colorless. They grow in every angle and if left long enough, resembling quartz sea urchins. Later, I will try to seed some to grow in a specific area. As of penning this, we have yet to determine exactly what chemical these are, but there seems to be a fair amount of them, as I have about ½ of a 2-gallon bucket full with another batch still growing.
These beauties come with a price, they tend to grow a bed horizontally across the surface of your vessel. This action sealed off the carbonate below, and the addition of more acid yielded no reaction. Cracking this layer with a steel bar caused a mass reaction resulting in a minor overflow, creating the loss of an estimated 1.5 liter loss of solution to the ground. The ground solution yielded no further reaction when sprayed with additional acid or base, leading me to believe the already neutral solution floats on the unreacted solution; a hypothesis actively confirmed when volumes increased and reaction ignition delayed.
An interesting note: the precipitate formed in the large scale reaction was the same cloudy, curdled appearance as in the lab, but had a much darker forest green color; akin to This Sherwin Williams Code. I have a theory as to why this is: when I was draining batteries, I tried a couple of different collection methods. One was setting the bottom of the battery on a little stand I made from scrap steel, and leaning the other end on a box. This placed the battery at somewhere around a 25-35 degree angle, and let the acid drain out nicely.
This stand withstood repetitive immersions with ease, as I cleaned it off after every use with some tap water. Once, however, I forgot I had drained a batch of acid for around 2-3 days. This ate away at the support structure, dissolving much of its iron into solution. This could cause the aforementioned lab trials to be red instead of green. I will do a few more individual trials as I get batteries, and will see where this progresses.
As of today, I've added around three gallons of distilled water to the mix in cleaning the crystals. I've filtered them out by using a stainless steel round sieve (like This one) that's long enough to span my 5 gallon bucket. This catches any crystals large enough to maybe cause a problem in the distillation process.
05-10-2016 Update: I've begin the final touches to the still I made a while back; silicon-ing up pinholes in the welds and securing the temperature controller. I've siphoned off almost exactly five gallons of solution off of the crystal beds of both buckets. This is >90% clear solution, so this should go fairly quickly, depending on of the salts deposit themselves when the water gets boiled off. I still need to get a proper collection vessel before I begin distillations, but I'm planning on starting with the vessel 1/2 full, which comes to about 2-2.5 gallons, by a rough estimate of holding up a 2 gallon bucket next to it.
The next step will be to crack and filter out all of the crystals, so that we just have precipitate left in solution. I'll wash the mass of crystals with distilled water again so I can capture the precipitate sans solid.
I attempted a distillation this past weekend.
It failed. To explain exactly why that happened let me talk you through the anatomy of a used r-134 tank (My main body):
From the bottom, there is a stamped steel body that is welded along its equator. The bottom has four indentations that serve as feet. On the top, there is a stamped steel handle/valve guard that is spot welded in place. In the midst of this there is a simple valve, most likely a globe style, which allows the user to regulate the pressurized release of the refrigerant. The valve has a ¼” male flare fitting as its factory output.
I was originally going to cut the valve off, build a column, and make a proper still. I decided to cut corners and I opened the valve entirely, cut the handle off, drilled a hole, and fed the thermocouple through it in order to gain accurate measurements of the vapors. I made a flare to brake fitting adapter to connect the condenser (Which worked pretty well. Only had two minor leaks! WOO!) to the main body, and ran ice-water through the condenser. I used an electric single range element so I could operate this indoors, and purchased the same temperature controller I used at school. the stack of wood underneath the condenser was there for initial support, as the condenser was a but heavy for the empty body to balance.
The big thermometer was purchased from Clawhammer Supply, and was installed long before the temperature controller was a thought, although I did cut it off and angle it up to aid in drainage and cleaning.
The primary issue with the whole ordeal, is that I overfilled the tank (the coil survived!) and the boiling water found it's way into the condenser, and consequently into the "distilled water." I believe a fractional column would help mitigate this, and give me better success.
I cut the power and, once the water cooled, I dumped the solution back into the 5-gallon bucket. I'm going to build a new still from scratch, and I'll run this bucket through separately, to recover what I can.