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12:00 AM
>If this is done in vacuum, the temperature where that starts would be lower
no, it's not. 1 bar does not make such great difference for melting and crystallizing solid materials. Hae calculated influence for aluminum melting point(rough estimation) results are so insignificant that even not worth of mentioning
>the Moon doesn't have enough silica for it to aggregate as a pure mineral (quartz) at the end of a magma crystallization process.
needs clarification here what do you mean.
also funny video about sand https://www.youtube.com/watch?v=pxmHHoTPSKI
https://isru.nasa.gov/OxygenfromRegolith.html
40% od SiO2 more than enough of anything
 
12:16 AM
@MolbOrg perhaps it is different with molecules. i have a handbook about vacuum furnaces that lists the melting point of a number of metal oxides as being quite a bit lower. let me look for the link.
hm, probably i misinterpreted a chart about vapor pressures of various metal oxides at different pressures
i made a chart a year or so ago that was based on a chart in that booklet, and i think i mislabeled it
@MolbOrg the silica bonds with other metal oxides in the melt, and only if there is silica left over once everything else is bonded does it crystallize as quartz.
yeah, i can edit that to make it clearer. and i'll take out the stuff about different melt temperatures.
 
12:36 AM
@kimholder actually the chart is excellent and exactly what you need to purify glass with simple means, but I didn't end to read the post(fighting with style atm, can't read wall of text on dark background, at least on the laptop)
 
oh, it's hard to read? not enough contrast?
hmm.... as i get older i notice i have more difficulty reading with the colors reversed too... i've always really liked the look of light text on a darker background, but i think i could reverse that in a way that still keeps the feel...
i'll play with it over the weekend
 
12:54 AM
yeah, i'm trying a set of light colors. i can change it over in a bit - i just need a little time to change all the text color, there are a bunch of them.
 
@kimholder it may be personal, at first glance is fine looking no problem there. Just my personal thing probably
 
well, i'm going to play with it a little. i set all my programs to dark backgrounds, and many of them come that way now. however, you are not the only person to have mentioned it.
the website is now set up in a format that makes it easy to play with colors, i can change things across the site by changing a short list of color classes
at any rate... now i'm reading about vapor pressures
 
I prefer light colors for all my backgrounds so it need accommodation, I know people who use darker - matter of habit
btw https://upload.wikimedia.org/wikipedia/commons/e/e8/JSC-1A_lunar_simulant_60X.agr.jpg seems they have silica crystals or something similar, needs better information what regolith is on particles level. hmm if I recall correctly have seen something like that when searched about aluminum, have seen that on nasa site in projects about IRSU moon aluminium mining
 
1:12 AM
i have taken my data from the Lunar SourceBook. It focuses almost exclusively on plagioclase, pyroxene, and olivine
because there is pretty much nothing else.
i just did a search in it for quartz and found a good quote
> Silica minerals include several structurally
different minerals, all of which have the simple
formula SiO 2 . These minerals are generally rare on
the Moon. This rarity is one of the major mineralogic
differences between the Moon and the Earth, where
silica minerals are abundant in such common rocks
as granite, sandstone, and chert. The relative absence
of silica minerals on the Moon is a result of several
factors. For one thing, the Moon has apparently not
evolved chemically beyond the formation of a low-
 
@kimholder more or less it is what the video about sand was about. But it does not mean there is not enough material aka SiO2 to form anything while it is melted.
 
no, definitely not. the difficulty is getting it pure.
 
as about refining goes, I think you overcomplicating stuff
 
in what way? the method i ended up with seems pretty simple to me.
 
first of all there is a lot of dust on the surface, 6 meters deep, and 4 billion tons is not that much.
particles are not a homogenous mix of everything, but particles which more or less consist of different materials. That includes metal oxides, metal particles, SiO2 particles, with inclusions without inclusion fuzed etc etc
and thus the first stage is not melting, but separation of those particles,
the same way as we do that on earth with ores and such.
 
1:26 AM
that actually isn't the case on the moon. because all the particles were created by impact processes, they are all made of a mix of things. no particles are one thing.
the only exception is metallic iron, and to what degree that is really true is debateable
 
@kimholder ok I have to find the link, and no the statement is not true, for different reasons
 
things are separated on earth thanks to weathering. there is no weathering on the moon.
 
not only because of weathering and meteorites impacts can be considered as the weather.
a single impact melts the thing, and it then freezes again, and it has time to for crystals and such, next impact breaks the thing, and again and again, the different strength of impacts, so much of them that the surface is covered with 6-meter deep dust from those impacts
so on particle level there is separation of materials by different properties lize metling tempertures, strengh, etc
*like
 
i'm searching in that same book for any references to that. every image i've ever seen of a particle of lunar material has shown it is a mix of different minerals
but what you are saying is making me think, maybe i have heard some reference to that before.
 
not the link I recall, but just for the moment page 14 https://www.nasa.gov/pdf/203084main_ISRU%20TEC%2011-07%20V3.pdf
Yes it is a mix of different material, but the size of particles and that they exesting what makes the difference, the particles may form agglutinate of the same chemical compositions.
*still searching
@kimholder not the link I wished but exactly what I'm talking about nasa.gov/centers/johnson/pdf/282811main_ISRUDeansConf1006.pdf 3th page
 
1:50 AM
yeah, but those rock chips and beads are all made of different stuff. it doesn't say there was the particles are made of.
the other presentation shows a process that increases iron content, and that i can believe because it is magnetic.
what i really love about those papers are the images of the reactors. i'm going to have to go looking for the papers about those reactors.
doesn't say what the particles are made of, i meant...
i have to make dinner, MolbOrg, but i will consider further what you are saying
 
pay attention to <50 um particles aka dust, they are vapors, vapors different materials condensate at different temperatures and thus time after impact and thus different distances from the impactor. basically, that is the separation in rectifying column as is.
 
i'm going to read the whole Lunar Regolith chapter end to end, something i've never done. i usually look just for the parts i need at the moment.
 
but as you have heat you can just evaporate the stuff and condense it and collect it. SiO2 2200+ , and with reflectors, you can have about 5000-6000K max it is more that enough to evaporate and rectify the stuff you need and because of vacuum nothing stops you from doing that just in regolith bed
 
2:06 AM
collecting such hot vapors sounds challenging. how do you rectify such hot vapors?
 
not more challenging than rectifying two liquids with different evaporating temperatures
As usual, have a colder place, any surface below 2200K will be cold enough for those vapors to condensate.
the main problem is to have huge amount of cheap energy
 
i'm having a hard time imagining the process. having a surface that is so hot only the vapors with the hottest melting point will collect there is pretty high temperature material.
the energy doesn't really bother me, as you say, there is plenty of sun.
 
2:35 AM
no no no, the surface has to be below 2500K, it can be 100K, it can be 1000K does not matter it has to be below.
The process let say you pour the magma with small flow trough focal point of a lens, it heats there some stuff evaporates (with lesser boiling point - metals mostly), it flies down in a magma pond, pond constantly looses heat(walls, IR), and constantly is headed by incoming flow, and it contains stuff with higher boiling point, you pour the stuff through another focal point etc. one by one you boil off the different stuff with higher and higher melting point.
it do not have to be magma ponds and those magma flows, there are different ways to do the evaporation and separation of vapors
Another point and I go sleep
You do not have to have clear glass for the purposes you suggest it(if I understood correctly)
A nvidia debunking video about moon photo https://www.youtube.com/watch?v=syVP6zDZN7I it is interesting in the sense of getting practical feeling how bright is the sun without atmosphere
You will be ok with 50% or less transparency fo the glass, and to make it diffuse you will be ok with the crystals and inclusions and other opaque looking stuff.
 
 
2 hours later…
4:22 AM
@MolbOrg let me think about it a bit. for now i have to turn in. i'll look at this tomorrow.
 
 
11 hours later…
3:13 PM
@MolbOrg As far as that goes, yes, where glass is on ceilings, it doesn't need to be clear. But in a lot of places it would still be better if it was clear. In others it would be better to use cloudy and tinted glass because if it all got through it would be too strong. The atrium designs already reduces light by using beams between the glazed areas, so it would be nice if the glazing was transparent enough to view the sky.
there are also areas where the purpose of the windows is to give people a sense of the outdoors, in those places the glass needs good transparency.
@MolbOrg The thing is, unless the heat applied to the lava is only enough to evaporate certain things, that are easy enough to separate afterwards, everything will mix again when it solidifies on the walls. I guess that is what you are trying to say here, apply heat several times, more each time so that different things evaporate. That sounds feasible, it would be a question of designing the system to see if any problems come up. It does sound like it could work though.
This isn't so different from what the dust roaster does, actually. The only thing is that once the lava stream has been vaporized, the different components are separated by passing them through an electric field that causes different elements to deflect by different amounts. Collectors are placed in front of the different streams.
However, the dust roaster is designed to produce only pure elements, not metal oxides.
Unless what you propose could be done using only sunlight, i am not sure it would be an efficient way to do this. The dust roasters need a lot of power, but because they produce a range of really useful products, that seems acceptable. And actually, the slag would be calcia and magnesia, which are two of the metal oxides it would be convenient to have.
What i propose - assuming it actually works - produces silica, and possibly variants of it could be used to obtain other metal oxides like titania. It probably isn't going to give you good purity, but it could be good enough to do the job.
 
4:15 PM
@MolbOrg Okay, this blog post has now been edited both on the website and on blogger to remove the inaccuracies and clarify that point about quartz.
 

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