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Author: Subject: Reducing metal oxides with wood gas
WGTR
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[*] posted on 18-5-2020 at 05:37


Quote: Originally posted by Ubya  
WGTR thanks a lot really.
i've been trying to convert lead oxides to lead metal from batteries for years (mostly because i try once every few months lol). The first time, i tried mixing charcoal, lead/lead dioxide powder in a steel can, lightning it up and feeding air from the bottom, it kinda worked but the amount of lead smoke it made was something i couldn't accept.
Then i tried again but lowering the amount of feed air, so with cooler temperatures the fumes would be less, but now lead dioxide would decompose to lead oxide and partially melt, at higher temperatures it would flow easily, but at colder temperatures it was dense as cold honey, slowly covering the charcoal and stopping combustion.


Your welcome. No problem...


Quote: Originally posted by Ubya  
I knew that hydrogen was used to reduce copper oxide as a lab demonstration, so i checked if it could be used for lead oxide also. there aren't any videos showing it but it is possible and even at a quite low temperature. the issue was to produce enough hydrogen to reduce 20kg of lead oxides without blowing me up.
a few weeks ago i tried another approach, putting a mix of lead oxides powder and charcoal powder in a small can, and heating it externally to red hot for a few minutes (until i finished my butane canister)


Yes, I think that external heating is they key thing here. A self-heating reaction is going to be a headache even on the best of days.


Quote: Originally posted by Ubya  
The metallic shine was awsome, it worked, and the initial decomposition of lead dioxide to oxide even made the heating process faster as the oxygen formed ignited the charcoal powder around each grain heating the mixture from the inside, the ony issue i had was that i needed a furnace to hold a crucible with the mix and not being able to go outside i couldn't buy the stuff i needed.

but now you showed me i could use alcohol vapour as a reducer.


instead of bubbling an inert gas through the alcohol and then heating the vapour mixture near the oxide, couldn't we just boil some alcohol and direct the vapours on the heated oxide? this way we remove the use of an inert gas or the added complications of using air and trying to not make the apparatus explode


Yes, you can use pure alcohol vapor. However, everything after the alcohol will need to be at a higher temperature that the alcohol itself, to prevent alcohol vapors from condensing on various internal surfaces.

Condensed alcohol vapors tend to collect into beads. These tend to run down the sides of cooler surfaces and drop unexpectedly onto hotter surfaces, causing flash boiling and mini-explosions. This is why I use a carrier gas at room temperature: bubbling a gas through alcohol at room temperature actually cools down the alcohol a little bit, making it the coldest part of the whole system, preventing alcohol vapors from condensing on any surfaces downstream. Also, by not actively boiling the alcohol, I am avoiding issues with "bumping" and sudden flash boiling in the alcohol reservoir.

However, if care is taken to keep the entire system hotter than the boiling alcohol (and using some boiling chips perhaps), then no carrier gas i needed. Just be careful combining large quantities of a flammable liquid with high heat conditions. I would rather suggest embedding a stainless steel capillary into a heating block, and forcing room temperature alcohol through that under pressure. The capillary would be injecting directly into a hot reactor in that case. The alcohol would basically be boiling as it leaves the nozzle, without cooling down the reactor (provided that enough energy is put into the heating block for complete vaporization).

[Edited on 20-05-18 by WGTR]




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Refinery
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[*] posted on 16-6-2020 at 09:57


Lead acid batteries, when fully charged, should contain mostly PbO2 and metallic lead. When drained, they should contain mostly lead sulfate.

The salts of lead can be decomposed into lead oxide by heating over 1000C.

Should this be practically viable with propane torch?
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[*] posted on 16-6-2020 at 13:14


I've taken a number of batteries apart and there is rarely ever any PbSO4 in them and if there is it's usually on the Pb plate and not the PbO2 plate as much. I was thinking about taking some sheets of ABS or HDPE and putting the PbO2 plate on them in the oven so I can make a large flat electrode that won't crumble in the tank.
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[*] posted on 16-6-2020 at 14:08


Quote: Originally posted by Refinery  
Lead acid batteries, when fully charged, should contain mostly PbO2 and metallic lead. When drained, they should contain mostly lead sulfate.

The salts of lead can be decomposed into lead oxide by heating over 1000C.

Should this be practically viable with propane torch?


issue is, you usually recycle dead batteries, not fully functioning ones





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