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Author: Subject: Preparation of elemental phosphorus
Magpie
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[*] posted on 11-10-2017 at 04:23


I like your design, but would make a few changes:
1. Change carbon to aluminum.
2. Monitor all condensers for temperature and control to the optimums.
3. Incorporate cyclone separators where needed to separate gasses from the liquid Phosphorus.






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metalresearcher
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[*] posted on 11-10-2017 at 09:20


This would be a rather compled design. It needs indeed strict temperature control in the condenser. But what is actually the problem that CO and P4 arrive together in the condenser? They don't react with each other and can easily be separated by condensing the P4, as CO remains a gas.



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Magpie
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[*] posted on 11-10-2017 at 10:27


My suggestions are for producing clean P at high yield, not for convenience of the operator.

Use of carbon vs aluminum will greatly increase gas formation, and decrease the necessary retort temperature. My experiences with aluminum and SiO2 produced a nasty voluminous slag that contaminates the P.

Use of a centrifuge for gas-liquid separation would be wonderful but indeed too complicated. A cyclone might work just as well and be far simpler.

[Edited on 12-10-2017 by Magpie]




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[*] posted on 11-10-2017 at 21:54


@metalresearcher i think the problem is that the combined pressure of the gasses being produced and the high temp make condensing the P4 a quite challenging, a liebig type condenser may not be enough to condense all the P4 and a large amount may possibly be lost out the top (hence my idea of using a stopchock).

Unfortunately I have no idea just how quickly the reaction proceeds beyond what BluePlanet1 described, what he described seems quite intense.

A possible simple solution, if the condenser is not enough would be to pack the condenser with a material with high surface area such as glass wool.

@Magpie i do like the cyclone idea but im a tad confused as to its operation.
Is the spinner supposed to rotate solely by the pressure of the gases being pushed through or would it have to be electrically driven.
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[*] posted on 11-10-2017 at 22:32


A cyclone has no moving parts. It spins the gas into a vortex. Denser material is flung out to the edge and funnels to the bottom. Light gas leaves at the centre top so that gas flow is maintained.

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[*] posted on 13-10-2017 at 11:42


The cyclone separator would appear to be a lot easier to engineer than i had originally thought.
One problem though: from what ive read on them cyclone separators are only capable of separating particulates or liquid droplets from a gas flow, they cannot separate 2 gasses at all.

This means that we would still need to condense the P4.
A water jacket around the cyclone housing would be the minimum required to accomplish this. Achievable but it makes other methods look more appealing.
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[*] posted on 13-10-2017 at 12:09


I'm really confused as to why the "just use a longer pipe and submerge it very deep in water" method is not being taken more seriously. Using water eg one meter deep should condense most of the phosphorus. It's not like you have any other condensates to worry about.
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[*] posted on 14-10-2017 at 00:11


First the P4 must be condensed using a proper condenser. Then it will drop out the bottom of the cyclone into a water filled receiver. Gasses will leave the top port of the cyclone, hopefully relatively free from P4. Cyclone design will be important, as well as condenser design and temperature.



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[*] posted on 14-10-2017 at 02:50


Quote: Originally posted by Magpie  
First the P4 must be condensed using a proper condenser. Then it will drop out the bottom of the cyclone into a water filled receiver. Gasses will leave the top port of the cyclone, hopefully relatively free from P4. Cyclone design will be important, as well as condenser design and temperature.


So is the problem believed to be that the phosphorus condenses to a fine mist or dust that does not easily settle?

Looking at the short exit pipes and large bubbles in the water I would think cooling is the main problem. One end of the exit pipe is at +1000C with the gaseous CO and P even higher and only about 200mm of air cooled pipe to get the temperature down to say 200C.

The large bubbles so near the surface probably don’t wash out the P or cool it very efficiently particularly given the flow of CO.


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[*] posted on 14-10-2017 at 03:40


Yes, condenser design is important and less than optimum design was the cause of many of my troubles. Even though I generally used aluminum as reductant the gas/P/slag rush could be explosive. I used an air condenser made of 1/2" electrical conduit (EMT).

Gruson did excellent work with the help of his science teacher and some welding craftsmen. Here is a link to his work: https://www.sciencemadness.org/whisper/viewthread.php?tid=65...

Unfortunately his photos are no longer available.




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