The red color the melt takes on is actually from potassium chromate itself. It's a little known fact, but the salt is thermochromic, changing towards orange or even red at high enough temperatures.
I found it more convenient starting from chromium hydroxide or chromium metal - the metal is very hard but can be shattered to small pieces by hammering in a covered steel mortar. It is then dissolved in acid and oxidized. Dichromate of sodium is valuable due to it's high solubility while that of potassium as a standard. I found one patent on preparation of sodium dichromate using sulfuric acid, the excess acid being removed as sodium sulfate and the excess sodium as bicarbonate (by bubbling CO2 through the mother liquor). I've look up preparing sodium dichromate from potassium dichromate - this might be done by removing potassium as iodate (the potassium iodate is even less soluble than potassium dichromate). However once we have the potassium salt, it's cumbersome to get the sodium salt as most potassium salts are too soluble and we would have to go through chromium trioxide, back through chromium hydroxide or oxide or maybe even through chromyl chloride.
Great video! Have you considered the very similar permanganate synthesis? I know manganese dioxide is pretty widely available (I purify mine from alkaline batteries), and permanganates don't seem to be nearly as toxic as chromates and dichromates, so it might be worth a shot!
NurdRage has a video on it, there still is no good breakthrough in making potassium permanganate in lab scale though. The main problem is that you can't easily get it to crystalize as any organic impurities whether that be fibers from your filterpaper or the oil droplets that are naturally in the air
Check out water filter stores, I bought ten pounds of potassium permanganate at one ten years ago for $60. Needless to say, I still have at least three quarters of it still. It's super useful, but you rarely need much.
Extracting the nitrite from this synthesis could be interesting too, it's hard to get in some parts of the world. I guess they don't want us making tetrazoles, or GHB.
Okay, looks like you had the same filtering issues that I had. I even tried a glas fritted (40 micrometer) Buchner funnel with filter Paper in it but even that pulled through some chromium oxide at first. I regret using that glas fritted Buchner because it's permanently green now. Even after leaving it in H2SO4 + H2O2 over a week.
You may want to consider using Celite in your vacuum filtration setup it will catch those first very small particles that got through the filter paper.
Potassium dichromate have a lot lower solubility than potassium chromate, so if you acidified the (COLD) filterate with acetic acid, collect the dichromate crystals, redissolve it and basify the solution, then let it evaporate, the yield would be a bit higher i guess. That's how I'm making mine, I just don't basify the solution just but recrystallize it, because I use dichromate. Btw good video! New sub!
@ THYZOID LABORATORIES Quite funny, I actually thought you would do a video on extracting chromium in the form of a chromate or dichromate salt from stainless steel. That could also be quite interesting. And by the way, if you want to make potassium dichromate from that potassium chromate and potassium nitrite, you will have to deal with the latter somehow, otherwise you won´t get potassium dichromate and instead you will reduce the Cr(VI) into Cr(III) when you acidify the solution.
@@THYZOID No worries! And another thing, if want a much better and cleaner way to make potassium nitrite, you can melt a mixture of potassium nitrate and potassium hydroxide and then carefully add little bits of sulfur at a time. 3 KNO3 + 2 KOH + S = 3 KNO2 + K2SO4 + H2O
@@THYZOID You can get cheap stainless steel cutlery at second hand stores for really cheap. I'm sure you could buy enough for the synthesis for less than twenty dollars.
How do you make and print your labels, do you create an image in an app and load onto a handheld sticker printer? I was thinking of getting one of those
Awesome furnace!! ❤️ What did you coat the inside with? Also I have wanted to ask when using the gas cylinder is there any chance of suck back when using it like that?
