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semiconductive
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Making borosilice fritted glass for distillation
Does any one know of a simple way (closer to foolproof) to make a borosilicate glass frit?
I'm wanting to modify a vacuum distillation tap to protect the air/vacuum pump from polar chemicals using a frit barrier and hydrophobic coating.
I'm concerned that if I just crush up borosilicate glass vials into frit and try to melt/bond it with a oxy-acetyline torch, I will either have loose
glass or fused air-tight as it's hard to heat everything perfectly.
I was hoping someone might have experience with a mixture that would allow me to make reasonably consistent (amateur) glass frit/porous glass plate.
Perhaps a method like mixing water glass, borax, and some kind of pore-maker chemical; eg: table salt or another salt which would not fuse with the
glass so that the glass can be torched heavily with the salt present -- but then cooled and rinsed to produce "holes"?
I'm wanting to make and bond a borosilicate frit to a borosilicate vacuum take off (eg: having same coefficient of expansion) . See photo:
I'm wanting to make the frit in the green marked area outside the drip tube but inside the adapter.
Background/reason why:
I've found that I can distill H2SO4 at much lower temperatures by making a reflux column with a condenser tube Tee at the bottom and a standard
consensor below. The condenser tube is kept just above the boiling temperature of water. Then I pump air into the boiler flask blowing it on the
surface of the acid and then evacuate the same air after the collection flask. The result is similar to steam distillation, but with most of the
water staying in the boiler flask and reflux column. I'm able to get reasonable quantities of concentrated and distilled H2SO4 at 150C or below. I
can then reflux the end product to make it more anhydrous as needed. This technique is probably useful for other chemicals as well, so I'd like to
make a general purpose apparatus.
The only issue I had was that I need to keep as much of the sulfuric vapors out of the air pump as possible while recycling the air.
I can reduce fumes getting to the vacuum pump by putting a glass bead on the vacuum takeoff valve adapter to "plug" (not seal) the drip pipe. See the
red dot in the picture. That's where I put a glass bead. As soon as moisture covers the bead, air pressure will push droplets down the drip pipe
and they will collect as liquid. Almost no sulfuric fumes remain in the air. However, after sitting for a long while ... some of the liquid will
re-vaporize and since the vacuum take-off is completely open -- some vapor goes into the pump.
I thought of just making a sodium carbonate trap before the air pump; but would like to try a permanent -- no maintenance method -- to remove as much
acid as possible before a chemical trap.
My thought is that the ideal , non-exhaustible, pre-filter might just be a glass frit (similar to the glass bead) . The frit would again condense
fumes out of the air because it's hydrophilic. To prevent reasonably strong acid from being forced through the frit by vacuum , I can just dissolve a
hydrophobic substance like silicone caulk in MEK and coat the top of the frit with it. A thin coating of silicone will pass gasses but not liquids.
eg: silicone will not pass water or acids -- but it will pass air, slowly.
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aga
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Conc sulph seriously cannot be worth this amount of effort.
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semiconductive
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You're correct; I can make concentrated sulphuric by just concentrating battery acid from NAPA. But making the acid isn't the only reason for
distilling it ... There are several other reasons; such as recovery of sulfuric from a reaction and not putting waste acid in a landfill, not flushing
it down my septic system; etc. Being able to recycle sulfuric at low $$ is a good thing to be able to do.
There are other chemicals that this apparatus will recycle as well. Anything that lowers the heat required to recycle chemicals also reduces bills.
esp. as I scale the process up.
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j_sum1
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Really good question.
There are a couple of glass blowers here who might have some specific knowledge. Let me give my (totally unsupported) thoughts.
1. I think you will need uniform heating -- no flame which will give localised hot spots and hence melting. You need to sinter the glass frit while
keeping the remainder of the structure unchanged. This will mean a kiln.
2. I would assume that the composition of the frit is different from the borosilicate. You do not want the structural glass softening and deforming.
You might get some progress with sodalime glass and controlling the temperature. You might also try a mix of crushed sodalime and borosilicate
powders.
3. You might get some success with getting piece of frit and sticking it in place with epoxy putty. If it works it will be an easier solution --
even if you need to replace it every few runs.
4. My first attempt would be to see if I could achieve the required result using a rolled up wad of glass wool. That may well be the simplest
solution of all.
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j_sum1
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Or buy this and use it with other adapters (female to female) to get the configuration you want.
https://www.ebay.com/itm/A-C-Glass-Medium-Fritted-Vertical-V...
Edit
In closer look, not exactly what you want. But you might be able to find something.
Alternatively, if you are ok with melting glass, it might be easier to dremmel and weld bits of glassware together. This could be better than making
your own frit.
[Edited on 23-4-2018 by j_sum1]
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semiconductive
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Wow, I hadn't seen that before on ebay. I'm using 24/40 ... so I would need to buy the $39 version. but....
Unfortunately, the frit on the adapter you found is on the end where the glass bead normally gets put. (red mark on my diagram).
That only solves the easy part of the problem...
The vacuum take-off is still open to fumes ... so it's not an off the shelf solution.
If I could find a cheap piece of frit the exact right size -- rather than $89/random sized fritted disc, I could probably just use water-glass to
bond it to the body.
But I don't see any easy way to locate a borosilicate frit disk of exactly the right size with a stem hole in it; and I'm not sure how difficult it is
to drill a hole in a frit filter plate.
Otherwise, I do know water glass dehydrates and becomes silicon dioxide at a much lower temperature than the melting point of borosilicate.
Once dehydrated and washed with strong acid, burnt silica gel is chemically inert.
So, in theory waterglass would be an easy way to weld a borosilicate frit to a borosilicate body using a torch without warping the body.
I can make a kiln, if necessary. That's actually not hard to do. But, I'd like to know an actual glass blowers advice before trying that. I want to
be sure to succeed if I go to that much work.
Edit: I saw your edit a moment ago;
I will look for glass wool; that's probably a good alternative if it works.
As to cutting glass and welding it:
Thick glass tends to break strangely when I score it. I tried making an adapter with an extra long european joint short by scoring the joint and
breaking it -- but it broke wrong. I would really appreciate knowing if there is an abrasive or way using a dremmel to cut glass at home with less
risk than scoring glass.
In order to weld I must first cut off the existing vacuum tube in order to be able to weld a frit filter / buchner funnel / chromatography column in
it's place. It would need to be welded such that liquid condensate refluxes back into the collector jar.
Being able to cut odd shaped glass reliably is important to me; I'd love to learn the skill if anyone knows how.
[Edited on 24-4-2018 by semiconductive]
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Heavy Walter
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I work with a glassblower who prepare its frits.
He grinds in a ball mill pieces of borosilicate glass.
Depending on the desired porosity he choses a particle fraction using sieves.
Then he fills an iron mold –cylindrical, typically 5 mm height, previously brushed with colloidal graphite- with the selected fraction.
Then puts it in a kiln, at some specific temperature depending on pore size for a specific time.
Then he seals the frit to a joint.
Having other questions, I can ask him.
[Edited on 24-4-2018 by Heavy Walter]
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RogueRose
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I don't think it should be too difficult as I've watched a glass blower do something similar. I've been keeping my broken boro (quality Kimax &
professional Pyrex) for things like this. It will all depend on what type of boro you are working with but a good rule of thumb is that it has a MP
of about 1500F and an annealing point of about 1,020F.
You have to make sure that you aren't working with quartz glass as that has a much higher melting point and if your frit is quartz, then your "funnel"
is going to melt well before if it is boro. Now Wiki does list that lampworking/scientific boro glass has a melting point of 3000F, which I think is
totally incorrect b/c this is just under the MP of SiO2 at 3155F. Now maybe the glass they are talking about is a 99-99.5% SiO2 & .5-1% B. Now
"fused silica", which is what quartz glass is also often called, is stated as having a MP of 3000F.
I would take your scrap glass, crush it w/ mortar and pestle and then sift it with different size screens/strainers, etc. you can make something for
small particles by using a needle or pin and poking small holes in thick paper and then using that to sift the finer particles through, I've done
simialr and it is slow, but it will work. for the size you have it may not take a lot of time.
You might also want to try a coffee grinder for a few short bursts. I'd also consider taking something like some ball bearings of nuts or even bolts
(ones of moderate size of 1/4" diam minimum for bolts), put them in a sealable container with your fine-ish glass, close lid, then shake/swirl
vigorously. This should help break off and round off some of the very sharp edges which can really cause some problems by making large spaces between
other pieces. Don't go overboard unless you want finer particles. You should be able to feel a big difference in the texture after doing something
like this. Of course a ball mill would work as well, but the other way allows for more visual control I would think.
If you have never worked with melting glass then try to melt and bend some tubing if you have it, old broken lab glass, any light bulbs of halogen,
metal halide (high pressure sodium or Mercury Vapor), though many halogen may be quartz (most of mine are).
Once you have the particle sizes you want, you can fill the entire bottom with the fine glass. When you apply a blow torch to the outside (to heat
outer glass evenly) this expands the glass and then you can apply the heat to the top layer on the inside until it gets a very slight orange (best
done in low light conditions). This will make a layer that should hold in place if done correctly and allow most all the glass underneath to fall out.
This could be a thin layer and that is good as you can place more on top of this and heat again to give a slightly thicker layer.
Without better pics of how the adapter looks from the bottom, I don't know what else to say. I think you should be able to do this with a standard
propane blow torch with no problem (as long as it is standard borosillicate). I'd be very hesitant to use any gas that is hotter. I have used the
least expensive benzomatic propane torch with a not-so aggressive flame head (not extremely focused), with great success joining1.5" diameter glass
tubing to each other (I use one torch for each tube, then one when pressing together to heat).
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semiconductive
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@Heavy Walter: I think I can do that if you give me the specifics I need to know.
The frit filter I'm trying to make shouldn't be very fine eg: A. Coarser frit makes liquid flow easier and drip out, so a typical coarse buchner
funnel kind of frit, or even a little coarser would be OK.
I have a rock tumbler that can be used as a ball mill.
The plastic, though, won't work well. It'll get mixed in the sharp glass.
However, I can put borosilicate glass vials in an iron can with an iron bolt and place it on the rock tumbler.
if I use Iron, maybe a rare earth magnet will be able to get rid of iron dust found in the glass after milling -- unless there is something better
your friend recommends.
I can also weld a second bolt to the side of the can, which will lift and drop the glass and iron bolt repeatedly.
I'm not sure what size can I need to use, but I'm sure that can be made to smash glass up into all sizes of frit.
I've made sifters before. I used wire screen and plastic plant pot bottoms as a frame. I epoxy the mesh to the pot, and cut a hole in it to let the
dust out.
American window screens are about 20 mesh; 1/20 = 0.005 inch ~= 1.27mm
Is that a practical mesh for smallest particles in a coarse frit filter ? or is it too fine?
Secondly, what size mesh should I buy to get rid of glass particles that are too big?
To make the sintering work,
I imagine that your friend waits until the kiln has gotten to some minimum temperature before he begins timing the sintering.
Then he measures a time and has some kind of temperature profile he likes.
I have thermocouples and a computer control, so I can measure temperature to 0.1C and control the heating and cooling of a kiln very repeatably.
But I need to know how quickly it needs to heat up, and to what temperature(s), and how long it's to keep it there, and finally how quickly to cool
down.
I appreciate any information you can provide; as that's the difference between being able to do the project this way ... and not! 
[Edited on 24-4-2018 by semiconductive]
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semiconductive
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Quote: Originally posted by RogueRose  |
You have to make sure that you aren't working with quartz glass as that has a much higher melting point and if your frit is quartz, then your "funnel"
is going to melt well before if it is boro.
|
I have borosilicate glass tubing, B3.3 I think it was advertised as. I also have vials that have the temperature coefficient of borosilicate glass
when I measured them. I seriously doubt they are fused quartz, because they are quite inexpensive. This is also why I was thinking to use
water-glass and borax, because those two things together if mixed in the right proportions ought to make borosilicate glass. Water glass is sodium
silicate, and borax is sodium borate. Borosilicate glass, commercially, always has sodium impurity but not calcium. So, I ought to be able to make
borosilicate glass if I knew the right ratio to mix.
| Quote: |
If you have never worked with melting glass then try to melt and bend some tubing if you have it, old broken lab glass, any light bulbs of halogen,
metal halide (high pressure sodium or Mercury Vapor), though many halogen may be quartz (most of mine are).
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I've gotten defective joints from china, before, that had wrong angles on them and heated them with my oxy-mapp gas torch and a Harris precision torch
body. The flame can be turned down very accurately and spread to control average temperature. It made bending borosilicate glass simple. So, I'm
not to worried about bending and welding; I'm just not sure I will be able to tell when a frit is melted properly or too much. Eg: the "art" side of
things isn't my specialty. That's why I'd rather do something that has a foolproof safety, or else build a precision computer controlled device to
make the frit correctly on the first try.
| Quote: |
Once you have the particle sizes you want, you can fill the entire bottom with the fine glass. When you apply a blow torch to the outside (to heat
outer glass evenly) this expands the glass and then you can apply the heat to the top layer on the inside until it gets a very slight orange (best
done in low light conditions). This will make a layer that should hold in place if done correctly and allow most all the glass underneath to fall out.
This could be a thin layer and that is good as you can place more on top of this and heat again to give a slightly thicker layer.
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I can try that on top of a fire brick with the frit before ever risking the adapter; but I have a sinking feeling I won't get it right. If there is
loose glas on the bottom after sintering as you suggest, then if I make more layers I might not get both layers to fully sinter or go too far. The
loose glass in the middle could be a problem.
Here's what the bottom looks like. Just a drip tube sticking out of a pipe that has a vacuum port on the side.
[Edited on 24-4-2018 by semiconductive]
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Dr.Bob
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I have some various 24/40 m/f jointed tubes with a frit in the middle. Not perfect, but might work. I'll look for anything like what you posted,
but I might have something close.
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Bert
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Ace glass is pretty good (excepting the prices- eeep!) equipment in my experience.
They make their fritted glass filters from chopped glass fibers. Never tried this, I have cut glass and done small fusing and glass blowing operations
only (and poorly at that).
The sincerest form of flattery is plagiarism-
http://www.adamschittenden.com/frit_info.html
Please do report on your progress,.if you ever get so far as making such tools.
Rapopart’s Rules for critical commentary:
1. Attempt to re-express your target’s position so clearly, vividly and fairly that your target says: “Thanks, I wish I’d thought of putting it
that way.”
2. List any points of agreement (especially if they are not matters of general or widespread agreement).
3. Mention anything you have learned from your target.
4. Only then are you permitted to say so much as a word of rebuttal or criticism.
Anatol Rapoport was a Russian-born American mathematical psychologist (1911-2007).
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semiconductive
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Thanks!
There is nteresting information on that link ... but its a bit incomplete / stumping.
I'm planning on using an aquarium air pump, as it's cheap, light, low-power, and the rubber diapragm can be coated with silicone to improve chemical
resistance a little bit.
So, I know my pressures are limited to around 30millibar and 250mL/minute airflow.
There should be a relationship between frit size and resistance to air that allows me to predict how wide and thick various glass frits need to be in
order to stay under 30millibars pressure.
I know an analogy that let's me relate flow rate to a crude figure of merit -- the "resistance" or relative resistance of a frit.
In electronics, electron flow in a conductor is similar to a fluid through a porous surface. There are obstructions causing collisions and
"resistance" to flow. So, The exact same proportionality formula ought to apply to glass frits.
Flow is proportional to pressure / "pore_resistance" * ( diameter**2 / thickness )
However, Adams/chitten doesn't show the thickness of the frits that they are measuring in their guideline chart. If I assume the discs are all the
same thickness, the proportion chart should be computed as the square of (size/30mm).
http://www.adamschittenden.com/Robu%20flowrate%20graphs.pdf
diameter AdCh theory difference.
10mm 0.13 0.11 84%
20mm 0.55 0.44 80%
30mm 1.0 1.00 100% ** nominal size and factor ( 30/30 )**2 = 1
40mm 1.5 1.78 119%
50mm 2.5 2.78 111%
120mm 9.7 16.0 165%
250mm 17.4 69..44 400%
450mm 32.5 225.00 692%
However, the formula doesn't work ... so either it's wrong, or the thicknesses of the frit discs generally get thicker as the discs get wider.
In another document, AdCh shows that "coarse" frits have average final pore sizes of 60 microns, eg: 0.06mm -- which is about 1/20th the size of a
window screen hole ~1.3mm. However, I don't know how the average pore size is related to the average glass particle size or how to compute that ....
AdCh does explain that coarse frits are about 40% (by volume) empty space.
There is probably a way to estimate particle size from that figure ; I just don't know it off the top of my head.
Edit:
The chart AdCh shows is actually from ROBU glass in Germany. I found a ROBU thickness specification, and frit discs do increase in thickness as the
diameter increases.
30mm wide is 3.5mm thick; so the difference percentage for selected diameters can be computed based on 3.5mm nominal thickness; Here's a table of
theoretical difference, vs. difference found in previous chart:
http://www.robuglas.com/en/sintered-glass-filter/filter-disc...
10mm 2.8/3.5 = 80% vs 84%
20mm 3.0/3.5 = 85% vs 80%
30mm 3.5/2.5 = 100% vs 100%
40mm 4.5/3.5 = 128% vs 119%
50mm 4.5/3.5 = 128% vs 111%
120mm 8.5/3.5 = 243% vs 165%
250mm 19/3.5 = 542% vs 400%
The general trend is correct, but there are fairly large random errors on top of a systematic one.
It's hard to tell what is causing the difference in percentage thickness from theoretical, but the correlation with thickness suggests that as frit
gets thicker, the pore sizes also get larger. I imagine that the particles near the surface of the frit might be more melted together than those
farther from the surface; so the thicker the glass, the less well sintered the particles would be near the center of the filter.
So, I think my formula is probably correct; but process variations vs. thickness are an unknown (on top of accuracy of measurement being
questionable, because manufacturing tolerances are not specified.)
Anyone else have any knowledge that I might have overlooked as to why the frits vary?
[Edited on 24-4-2018 by semiconductive]
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wg48
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As others have said it will be tricky to heat a pad of glass powder with a flame such that it only fuses the points of contact of the particles but
not so much that it melts in to a pad of glass with air bubbles. It will be much easer with a small temperature controlled furnace but some
experimentation will be required to get the correct time temperature. A programmable ramp and soak type controller would be ideal.
Perhaps I do not understand what you proposing in your distillation set up. You seem to be suggesting that by blowing air over the surface of hot
dilute sulphuric acid it will cause more concentrated acid to be volatised and leave more diluted acid in the flask. I would expect the vapour would
be more dilute acid or mostly water and what is left in the boiling flask to be more concentrated acid.
Incidentally it usual to bubble the purge gas through the solution and that will have the added advantage of reducing bumbing.
How does the frit stop sulphuric acid vapour? Yes it may capture sulphuric acid mist (droplets of acid) but not vapour or did you mean mist when you
used the term vapour?
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highpower48
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Doesn't Deschem offer to make custom glassware. Not sure but that might be easiest and cheapest way to go. If you don't mind Chinese glassware.
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semiconductive
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| Quote: Originally posted by wg48 | | As others have said it will be tricky to heat a pad of glass powder with a flame such that it only fuses the points of contact of the particles but
not so much that it melts in to a pad of glass with air bubbles. It will be much easer with a small temperature controlled furnace but some
experimentation will be required to get the correct time temperature. A programmable ramp and soak type controller would be ideal.
|
I have a program, written in Python, that has a PID servo type loop. It takes a list of times and temperatures and linearly interpolates between the
list elements to make temperature/time setpoints. I really hate doing a lot of experimenting when there should be a lot of people in the world who
already know the answer. Glass making for chemistry is something that lots of people have known in the past. Perhaps we're loosing knowledge due to
industrialization of labware.
I can make any piece wise temperature profile and repeat it, so long as the diffusion time of kiln-heat is small compared to the programmed ramp rate.
Eg: the smaller the kiln, the more precisely the temperature will be controlled.
The loop feedback time is three seconds.
| Quote: |
Perhaps I do not understand what you proposing in your distillation set up. You seem to be suggesting that by blowing air over the surface of hot
dilute sulphuric acid it will cause more concentrated acid to be volatised and leave more diluted acid in the flask.
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No, not quite. The volatiles will be at whatever concentration the moisture content allows.
| Quote: |
I would expect the vapour would be more dilute acid or mostly water and what is left in the boiling flask to be more concentrated acid.
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Yes, that's probable.
| Quote: |
Incidentally it usual to bubble the purge gas through the solution and that will have the added advantage of reducing bumbing.
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That would not be a good idea, as there are liquid impurities in the boiler. If I bubble air through the liquid, droplets of acid with impurities
will be splashed into the air stream as bubbles pop. I have thought about making a straw like shape out of porous frit with larger holes in it. The
frit would "wick" the boiler liquid up and give more surface area of boiler liquid for the air to come into contact with, but without splashing or
bubbling.
Even without a "wick"; There is no bumping because the sulfuric acid is not boiling. At 125 to 150C, we simply have humid air in laminar flow across
the steaming liquid's surface. Water will steam out slowly, but not boil, because the acid has raised the boiling point of water significantly.
In an actual experiment; The air temperature was actually close to 25C when it first comes in contact with the boiler acid. ( I intend to pre-heat
the air in future versions of the still). So, there was a mixture of water droplet (fog) coming into contact with the acid and steam as the acid
heats the air. As the air warms, the steam droplets disappear.
| Quote: |
How does the frit stop sulphuric acid vapour? Yes it may capture sulphuric acid mist (droplets of acid) but not vapour or did you mean mist when you
used the term vapour?
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You've overlooked a couple of things.
The frit after the collection flask is below the boiling point of water. Therefore, dilute water condenses on the frit. Whether the acid vapor is
droplets or individual molecules of acid is unknown and likely a mixture. However, in both cases ... the acid will either condense on the cool frit,
or it will bond to the water that is present on the frit.
I want a large surface area (thick frit) if possible to maximize the number of times humid air bounces or comes into contact with a hydrophilic
surface.
Because the frit is polar, I expect it to attract water molecules that are polar faster than condensation would happen on a cool hydrophobic surface.
Once a cool water film exists, it will collect acid vapor or droplets equally efficiently. Because H2SO4 is hygroscophic (it a great dessicator)
H2SO4 will "stick" to the water film preferably to staying as vapor in air.
A human nose is capable of detecting sulfuric acid vapors in the part per million. Even a glass bead with a water film on it is able to make the odor
so faint as to be nearly undetectable for several hours. So, I'm gambling that a glass frit will be at least as effective.
If I do not put the glass bead on the opening, however, there are open spaces where air can get into the collection jar without coming into contact
with a water film. In that case, the smell of sulfuric acid is chokingly strong. Even though I would expect the air to touch the condensor glass, or
the drip tube glass, a significant amount of air does not. It has to be forced into contact by a glass bead which has only microscopic sized gap.
The other thing you are overlooking is that there is a reflux column above the boiler (vigeruex). The vast majority of the water vapor condenses on
that reflux column and drips back into the boiler from the center of the vigerux. The top of the reflux column is capped with a marble.... so very
little acid or water escapes. Since the "condenser" three way joint / tap is below and leaves perpendicular to the reflux column; no reflux drips
into the condenser. The condenser is kept above 100C and is oriented vertically after the three way tap. That causes rising steam to go BACK up to
the reflux column rather than down the condenser and into the collection jar. A certain amount of water vapor will be forced down the condenser by
the slow moving air, but the concentration of the acid essentially increases as it goes down the heated "condensation" column. The "condenser"
column is essentially an acid reflux column in reverse. Both the reflux column and the condenser column could probably be made more efficient by
packing them.
[Edited on 24-4-2018 by semiconductive]
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Heavy Walter
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Hi semi
In case of a coarse frit -the largest porosity used in labs- he employs:
Sieve sizes: 20 and 40. All that passes through the 40, goes to be the frit.
Temperature & time: 850 ° C during 15 min
Good luck!
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semiconductive
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| Quote: Originally posted by Heavy Walter | Hi semi
In case of a coarse frit -the largest porosity used in labs- he employs:
Sieve sizes: 20 and 40. All that passes through the 40, goes to be the frit.
Temperature & time: 850 ° C during 15 min
Good luck!
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:S
If I use everything that goes through the 40, the smaller hole size, why would i bother using a 20 mesh? Doesn't everything that goes through 40 also
go through 20 mesh ?
Do you mean, everything that goes passes through the 20 to the 40, but not through the 40 is used ?
Thanks!
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semiconductive
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| Quote: Originally posted by highpower48 | | Doesn't Deschem offer to make custom glassware. Not sure but that might be easiest and cheapest way to go. If you don't mind Chinese glassware.
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No, I don't mind. Deschem's glassware looks green in the pictures ... which is odd for borosilicate glass. Lime glass tends to look green.
I'll try sending him a private message on ebay, and see what custom glass costs.
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Heavy Walter
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Hi Semi
You are right, I told it wrongly.
You have to use what rests into the 40 sieve.
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Sulaiman
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I'm dubious of the functionality of the device,
but I would try using a wad of glass wool to test the concept first,
just packed, not melted.
CAUTION : Hobby Chemist, not Professional or even Amateur
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semiconductive
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| Quote: Originally posted by Sulaiman | I'm dubious of the functionality of the device,
but I would try using a wad of glass wool to test the concept first,
just packed, not melted. |
I dont have glass wool yet, and I'm ordering 40 mesh screen. So If you have wool ... I would appreciate your trying that route if you would.
I'm still going to work on making glass frit, and am looking up information, while I wait for orders to be delivered.
I found an article with quite a bit of useful information on making efficient glass frit filters.
https://www.mvm.kit.edu/img/content/AME_Veroeffentlichung_Se...
[Edited on 24-4-2018 by semiconductive]
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aga
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In the end, you just spend time making money to Buy things that other people make all day long, rather than try to make them yourself.
In a survival situation you'd filter with bits of grass, so knowing how to make a glass fritt would not be of much use.
Knowing the exact process to make a fritt would be interesting.
Has anyone tried to contact a frit-maker ?
Last time i suggested phoning a manufacturer, they ended up with Free advice and a Free sample.
For those who do not know, 'phoning' is this Old thing that people used to do.
You use the 'phone' app on your smartphone and punch in the number of the company.
Sometimes an actual person starts speaking to you.
Crazy i know, but it happens.
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RogueRose
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Haven't read the whole thread, but you can order glass frit in different mesh sizes from glassblowing supply houses and it is pretty cheaply. I think
I remember something like 4-6oz for about $8 IIRC. Do a search for borosillicate tubes and glassblowing supplies and you should probably find a site
that offers this. I remember the place I saw even had some extremely cheap at a few $ for like 1/2lb but it may have not been screened for uniform
size.
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wg48
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semiconductive@
You seem to want to use the frit as a condenser surface and a molecular sieve. A condenser and or 500g of molecular sieve will work much better or
just wash bottle filled with a kilo of dry sand, crushed glass or sodium carbonate granules. .
Ok so your using the condenser as a heated unpacked fractionating column. So you expect the air and sulphuric acid/water vapour to flow in at the top
at the same time that water vapour flows out of the top. Why would that happen with the air flow and a condenser that must be cooler than the vapour
or none of it will condense?
I don't think it will work. But try it with glass wool. Wash the pump out quickly at the end and do report back.
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