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Vacuum System For The Fume Hood
Don’t mind the mess… Put together a much needed vacuum system for my fume hood entirely out of spare parts I had lying around. The pump, pressure switch and gauge actually came from a professional vacuum apparatus but I took it apart to repurpose it for myself, it also had a little compressor which I may or may not make use of at some point. The tank is from a pressure equalizer and everything else is just stuff I already had.
The construction is pretty simple and self explanatory. I added a trap full of indicating silica gel to remove moisture, there will also be an overflow trap between the outlet and whatever I am using it on. If I wish to vacuum distill any acids then I will just add a bubbler with saturated NaOH.
In my original design the valve and gauge were going to be in different spots so thats why I ran two hoses but I wasn’t really thinking about that after I changed it. I should have just put a tee on the main line, it’s purely asthetic though…
In all the system works really well and I didn’t have to bother with finding leaks so that was nice. The pump goes down to 400mBar and shuts off, it kicks back on at 500mBar.
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Simple methods for producing various uranium compounds
I dont currently have a big stock of uranium so many of these are low volume or dilute. My main interest in uranium chemistry for a while was just to refine some metal but as I have grown more advanced in chemistry it has shifted to the unending number of amazing compounds it makes. I try to stay relatively low budget so here I will discuss methods for producing them in a home lab and I will continue updating this as I discover new ones. In most cases uranyl nitrate will be the starting compound.
OXIDES
URANIUM DIOXIDE
The simplest method I’ve come across to make UO2 is to decompose uranyl oxalate.
UO2(NO3)2 + C2H2O4 = UO2C2O4 + 2HNO3
Boil the solution to drive off the HNO3, continuing heating will remove waters of hydration, CO2 and then decompose to UO2 in an inert atmosphere or UO3 in the presence of oxygen. A blowtorch or kiln is needed to reach the necessary temperatures, although I don’t have the exact number, above red hot is a good target. Heating in a tube or container with loose lid will cause it to fill with CO2 from the decomposition and yield pure UO2.
URANIUM TRIOXIDE & TRIURANIUM OCTOXIDE
UO3 can be obtained by heating many uranium compounds to decomposition including ammonium, nitrate, and peroxide. Complete decomposition temperatures and time varies but a few minutes at 300C should get you there and you will end up with a bright orange powder. If you notice it turning dark green then you’ve applied too much heat and converted it to U3O8 which occurs around 700C.
URANIUM PEROXIDE
Uranyl peroxide is as simple as adding concentrated H2O2 (~30%) to a solution of UN in nitric acid. Much more information on this process can be found here. https://www.911metallurgist.com/uranium-precipitation-hydrogen-peroxide/
UO2(NO3)2 + H2O2 = UO4 + H2O + HNO3
ALKALI SALTS
DIURANATES
Alkali diuranates are made by neutralizing UN with an alkali hydroxide giving the diuranate (MxU2O7) Where M is the alkali and x is the quantity. In the case of magnesium, MgO is used which hydrolyzes to Mg(OH)2 in solution.
Examples: ammonium (NH4)2U2O7, sodium Na2U2O7, magnesium MgU2O7
URANATES
Uranates are created by combining oxides at high temperatures or thermal decomposition of salts. Eg: Na2O + UO3 → Na2UO4. I have not made any uranates yet so I don’t have much to say here…
Image borrowed from wikipedia
https://en.wikipedia.org/wiki/UranateFLUORIDES
URANIUM TETRAFLUORIDE
UF4 is made by reducing UO2Cl2 to UCl4 and reacting with HF. UO2Cl2 is made by reacting any U oxide with HCl. Two good reducers are Zn and Sn dichloride. I have another blog describing how I made a PTFE apparatus for making HF.
UO2Cl2 + SnCl2 + 4HCl = UCl4 + SnCl4 + H2O
UCl4 + 4HF = UF4 + 4HCl
URANIUM HEXAFLUORIDE
Most of the routes to UF6 involve reaction with fluorine gas which is beyond the scope of any home lab and most professional ones but there is one route that is relatively simple. On the right side of the picture below there is a route that uses the thermal decomposition of UF4 to UO2F2 and UF6. This method is not used in industry due the formation of byproducts and thus there is very little information about it. I have not yet attempted it but I believe a copper reactor with a tube going into a glass vial containing NaF or KF in dry ice would work well. Alkali fluorides are effective desiccants for UF6, without them, any water present in the UF6 would destroy the glass by a cyclic reaction creating HF and more water.
CHLORIDES
There exists 5 chloride species of U. III, IV, V, VI, and UO2Cl2. UO2CL2 and UCl4 were discussed in the synthesis of UF4 so I won’t go into them here.
URANIUM (III, V, VI) CHLORIDE
UCl3 can be made by reacting UCl4 with hydrogen at high temperatures, UCl5 can be made by reacting UCl4 with Cl at 550C and and UCl6 is made by blowing Cl gas over sublimated UCl4.
UNCATEGORIZED
URANYL SULFATE
UOx + H2SO4 = UO2SO4
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Building a fumehood for home chemistry
Before getting into nuclear chemistry I always just did all my experiments in the kitchen and even for a while of doing uranium chemistry I was still doing it in the kitchen and for very obvious reasons I couldn’t keep doing this. The design I have come up with here is very simple and easy to build with some basic skills and only cost about $200. I am doing going to go into specifics of each part was assembled, rather this is meant to be a guide so basic building and design skills are necessary.
MATERIALS
– 2 sheets of 3/4″ 4×8 MDF (one of them cut in half longways)
– 2 sheets of 3/4″ 2×4 MDF
– 6 8′ 2×4
– 2 sheets of 1/4″ 2×4 MDF
– Lots of screws, 2.5″ and 1.25″ mostly
– A sheet of glass or plexiglass big enough to cover most of the opening
I started by building a frame for the work surface. I measured the height of a table to get a feel for how high it should be and after a couple years of use I am happy with what I’ve got. You will notice that the horizontal dimension is 49″, this is what the length of the 2×4 and width of the 4×8 MDF boards were. Not sure why they aren’t 48″.
All the pieces laid out 
I know my drawing is pretty crude but it works! Next I added the sides. They are simply screwed to the legs on the table and then I added the top frame. You will see that the side pieces of the top are recessed a little, this is so I can add a piece of trim and it will sit flush with the sides. The height of the top was determined by the size of the plexiglass screen that I had which came from a TV.
I didn’t think about this during construction but the blower must be mounted at the window and not at the unit! I eventually replaced this plastic sash with a piece of tempered glass. Next I painted the inside. I used ourdoor acrylic deck paint, it has proven to be pretty tough and holds up well. Because there is no overlap at the corners I used silicone to seal them inside and out. Apply this before painting.
After multiple coats of paint I added a light and a baffle with one of the 1/4″ MDF boards to help even out the exhaust flow and force air to be pulled to the back of the hood. I only left a small gap at the top so that most of the air flows through the bottom. Also some trim was added to the sides for the sash to be screwed to.
Testing the fit 
The square hole on the top was made round and a PVC toilet flange was used to attach 4″ vinyl duct. Another toilet flange was screwed and sealed with silicone to the blower inlet. I built a mount for the window which allows me to remove the blower. Because I have double windows the outside of the outer board was painted and a flap was added to close the hole when the blower is not in.
This Chinese adjustable hole saw is a little scary but has proven to be a valuable tool. Next I painted the baffle and added the rack using 1/2 Al rods that I bought on eBay, I already had the mounts. I finished up with the trim and secured the sash. The trim on the sides was cut short so that the other 1/4 MDF board could be slid in and out as a removable work surface. I use appliance epoxy spray paint to protect it although it doesnt stand up well against harsh chemicals, it still lasts for a long time if you take care of it.
Testing out the blower while I was waiting on my vinyl duct to arrive. 
After getting my lab put together and a year of us it inevitably gathered lots of clutter. -
PTFE apparatus for producing hydrofluoric acid
The finished setup, ready to distill. This is a very short and simple explanation of how I built an apparatus for producing HF which I needed to make UF4 in my quest to refine uranium from ore. Obviously HF is incredibly dangerous so I can’t be responsible for anything you do with this information.
I got a 200ml PTFE reaction vessel on amazon, it is a perfect choice for this application. I used 10x12mm (ID, OD) tubing and drilled a hole 10.8mm (7/16 or something like that?) into the side of the vessel and heated the tubing to force it into the hole. After heating again the tube expands to its original size and makes a very tight seal. The same thing was done to attach the condenser since adhesives & sealants aren’t much of an option for PTFE. The condenser is just a 3/4″ PVC tube with hose barbs and caps on either end. The reactor was wrapped tightly in copper wire to distribute the heat evenly and is placed in a sand bath. The receiving flask is PP with a tightly sealing lid which is charged with water prior to running so it converts directly to HF acid.
I did my first test run with 50g of CaF2 and 90ml of H2SO4. I only got about 50% yield, the rest was still in the reactor but after 3 hours I finally shut it down. The evolution of HF is very slow. I added ice to the remaining sludge to cool and dilute it, it makes an excellent rust cleaner!If one wishes to make HF just know that the CaF2 and H2SO4 mixture will foam up a lot. Start small and keep your total volume of reactants to less than half the volume of the container.
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Recovering pure uranyl nitrate with tributyl phosphate
Waste solution next to TBP after extraction Here I will describe my experience with using TBP to obtain very pure UO2(NO3)2. There are only a few scenarios where I see this being useful in the realm of hobby chemistry because it is fairly easy to get pretty pure uranium from the standard processes using acid or carbonate leach.
Two such scenarios are:
– Recovering U from small amounts of high grade ore
– Recovering U from samples with unknown contaminates
PROCESS
This only requires 5 ingredients and some glassware that any lab should be stocked with.
– Compound to be extracted
– 5M Nitric acid
– TBP
– Kerosene
– Water
For glassware you will need a stoppered flask and a seperatory funnel large enough to contain the entirety of the aqueous and organic solutions. A stir plate helps but is not necessary. As for TBP, I got mine from a friend who is a professional chemist, the only cheap source I’ve found online is alibaba. I was quoted $80 for 1kg of TBP with shipping, might be able to get a better deal from other sellers though.
Start making a mixture of 30% TBP in kerosene. I use 1-K from ace hardware, it’s pretty clean and cheap. Dissolve the uranium compounds in the nitric acid, this may require heating. It takes 2 mols of TBP per 1 mol of U so keep this in mind as to not saturate the organic phase, if you dont know how much uranium is present then best to err on the low side. If there is any undissolved particles at all then it must be filtered as they will create an emulsion. If you are extracting straight from ore then then you must remove the silica which can be done by simmering the solution with gelatin which will polymerize with the silica. A centrifuge would be a good option to remove the gel but I suppose a filter would work too, I haven’t tried doing this yet so I can’t provide much details here. If you do run into an emulsion, add small amounts of acetone and stir gently until it disappears.
On my first attempt I had undissolved solids in the solution which I did not know would cause this. The emulsion got much worse than pictured. Add your nitrate solution to the TBP solution in a closed flask and mix vigorously. You will see the yellow uranium nitrate go into the upper organic layer, I allow a few hours of contact time for this, best to leave on a stir plate at this stage. After a while you will notice that the TBP does not get any darker and at this point it is ready to be separated and then recovered from the TBP.
UO2(NO3)2 after migrating into TBP Add the mixture to the seperatory funnel and drain off the aqueous layer. The best thing I’ve found to recover the uranyl nitrate is near boiling water, sodium bicarbonate solution works really well but then you end up with sodium contamination in your product. Multiple washes are necessary as well as multiple extractions on the starting product to get a full recovery. Be careful when adding the hot water as the TBP mixture will ecaporate and build pressure fast in a sealed vessel. I prefer to use the same flask as before but loosely stoppered.
UO2(NO3)2 is very fluorescent and you can gauge how much is dissolved. Once you have your uranium nitrate back into water you can add hydrogen peroxide or ammonia to precipitate either uranium peroxide or ammonium diurinate and filter it. Both of these will convert to UO3 upon strong heating, around 300C. Stronger heating will result in U3O8. Either oxide makes a good form to store your uranium stock in, as is done in industry.
However… the precipitates of adding H2O2 or NH3 to the solution are incredibly fine and hold on to a lot of water and even small amounts will take a long time to dry even at high temperature. You will loose a small amount through the filter and also a lot will stick the filter which is not easy to scrape off, it is the consistency of peanut butter. If you wish to avoid this extra work you can just boil down the nitrate solution which will also decompose to UO3.
Small jar of UO3 recovered from TBP Due to the difficulty of back extraction into the aqueous phase I started looking for a better method and I found oxalic acid to be quite effective. I made an arbitrary concentration by dissolving 1g in 15ml of water and heating to near boiling, it effectively clears the TBP on the first wash. It cannot be precipitated with ammonia like UN but it can be boiled down and decomposed to UO2 if no O2 is present or UO3 with O2.
Testing my new method. The water in the flask was as attempt to recover the UN from TBP but it didn’t want to go into it. The test tube contains oxalic acid and it went into the water no problem, the TPB still looks yellow from reflection of the flask.
A site for me to document and share my projects with other home scientists.
Nuclear and High Voltage Science 