Hexabromobenzene
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Recovery of hydrochloric acid from metal chlorides
I have a lot of ferric chloride 2 from experiments producing alkali. If it is oxidized to ferric chloride 3, for example by bubbling air, it can
easily produce hydrochloric acid. According to the data, ferric chloride releases two-thirds of its hydrochloric acid at 180 degrees Celsius. I'm
considering a synthesis apparatus. A glass jar or a lined or enameled iron bucket could probably be used as a reactor. I'm concerned that the ferric
chloride will be molten, but it will quickly solidify, and even if it dissolves the iron bucket, it won't be critical.
On the other hand, aluminum chloride hydrate, when heated to about 220 degrees Celsius, also produces two-thirds of its hydrochloric acid. However,
heating it a little further will yield almost all of the acid. Also, aluminum chloride apparently decomposes from its solid state, which simplifies
the design of the pyrolysis reactor.
It is also possible that additional water will be required in the receiver, since according to calculations, there will not be enough water in the
hydrate to fix all the hydrogen chloride.
Any ideas on a simple, low cost pyrolysis reactor for this task?
[Edited on 12-1-2026 by Hexabromobenzene]
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chloric1
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You’re depending on the metal having higher charge density and small ion diameter. I have no idea if you have access to sulfuric acid, but if you
do, you would be able to reclaim HCl solution from a lot more chlorides like nickel, cobalt, zinc etc. You can even dissolve the metal chloride in
water so you can simply distill and collect azeotropic 20% HCl already dissolved. It comes over at 108 ℃ BTW
Fellow molecular manipulator
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Varungh
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Quote: Originally posted by chloric1  | | You’re depending on the metal having higher charge density and small ion diameter. I have no idea if you have access to sulfuric acid, but if you
do, you would be able to reclaim HCl solution from a lot more chlorides like nickel, cobalt, zinc etc. You can even dissolve the metal chloride in
water so you can simply distill and collect azeotropic 20% HCl already dissolved. It comes over at 108 ℃ BTW |
Sulfuric acid is more valuable than HCl. This is because it is restricted or is very regulated, to be said. Bisulfate can be used for the production
of HCl if required.
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Varungh
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In any case I won't recommend Fe.
Iron reduces FeCl3 to FeCl2.this destroys a bit of iron, and the reactant.
You can get quartz heater rods, one end sealed for cheap. Maybe try that
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Radiums Lab
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FeCl3 is valuable. If you really want to get rid, make ink. HCl can be obtained from PVC pyrolysis.
Water is dangerous if you don't know how to handle it, elemental fluorine (F₂) on the other hand is pretty tame if you know what you are doing.
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Hexabromobenzene
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I've done PVC pyrolysis many times. Firstly, the hydrogen chloride yield is always lower than the theory yield because PVC contains many additives
that absorb hydrogen chloride. A lot of calcium chloride is produced. Hydrochloric acid from PVC is always dirty and green, and also contains tar. PVC
pyrolysis requires heating to red heat for a long time due to the formation of porous carbon.
Metal chloride pyrolysis seems preferable because it requires much lower temperatures and metal oxides conduct heat well. Even a glass jar might be
suitable. This type of pyrolysis is also more compact than a PVC pyrolysis reactor.
| Quote: Originally posted by Varungh | In any case I won't recommend Fe.
Iron reduces FeCl3 to FeCl2.this destroys a bit of iron, and the reactant. |
I'll try aluminum and iron salts. I like aluminum better because it doesn't leave that reddish sludge that's so hard to clean and that contaminates
the acid.
[Edited on 18-1-2026 by Hexabromobenzene]
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Varungh
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FeCl3 is valuable. However, he is making it using his diaphram electrolyser, which turns iron annodes to FeCl2,which can be oxidised to FeCl3.for him
it costs mere pennies.
Now back to the Topic, FeCl3 is tough to decompose. It likes attacking metals, and destroying itself it this process. It also leaves a red coherent
sludge, which is tough to get out.
One can try using those pickling bottles and evenly heating it slowly. 180°C doesn't seem too unrealistic. Some oil baths can reach those
temperatures
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Hexabromobenzene
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What about aluminum chloride? Yes, its decomposition temperature is slightly higher, but there's a chance of extracting all the hydrochloric acid.
Direct electrolysis of concentrated salt with an aluminum anode produces a syrup-like solution with a density of 1.3. I believe it can be used
immediately, unlike ferric chloride.
I need to find a steam bath for a glass jar that can heat up to 250°C. This synthesis is non-flammable and forms a solid, so a leak isn't as
dangerous. Would paraffin work?
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Varungh
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| Quote: Originally posted by Hexabromobenzene | What about aluminum chloride? Yes, its decomposition temperature is slightly higher, but there's a chance of extracting all the hydrochloric acid.
Direct electrolysis of concentrated salt with an aluminum anode produces a syrup-like solution with a density of 1.3. I believe it can be used
immediately, unlike ferric chloride.
I need to find a steam bath for a glass jar that can heat up to 250°C. This synthesis is non-flammable and forms a solid, so a leak isn't as
dangerous. Would paraffin work? |
I dont think so. If any parrafin spills it will immediately ignite. Besides I have heated wax over a induction heater before. It starts smelling like
candles really fast, and I believe some of it vapourises.
If even one drop of water hits the hot bath, it will rapidly convert to steam and cause a little, fiery explosion. While this can be easily mitigated,
better to buy something else, instead of risking having to extinguish a pretty big fire
What about mineral oil? The transformer oil in transformers(duh) is rather heat resistant.
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bnull
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Low-melting alloy bath, something based on bismuth and tin. You must remove the flask before the alloy solidifies.
[Edited on 21-1-2026 by bnull]
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