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#1 2003-08-21 15:27:40

Bill White
Member
Registered: 2001-09-09
Posts: 2,114

Re: Supercritical CO2 - Useful technology?

Here is one link to a process that uses supercritical CO2 to modify Portland cement into a more useful form.

Using supercritical CO2 in making cement

Because supercritical CO2 also is a solvent, it could also be used to deliver metals, polymers or other materials into cement pores, thereby altering the surface chemistry to prevent penetration of other substances, Jones points out.

Might this process be adapted to make better "Mars-crete"?

In particular it seems that additives can be readily and easily dispersed throughout the cement mixture before curing which might allow "doping" the Mars-crete with useful substances to enhance performance in Marsian construction projects.

Supercritical CO2 can also be used to sterilize stuff without water, dry clean clothes (& dirty diapers?) and extract useful minerals from Marsian regolith. There will be no shortage of CO2 on Mars, right?

Anyone know anything about this subject not readily available on google? I hope to edit and add more links as time allows.

One more general link

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#2 2003-08-23 00:15:50

Shaun Barrett
Member
From: Cairns, Queensland, Australia
Registered: 2001-12-28
Posts: 2,843

Re: Supercritical CO2 - Useful technology?

Hi Bill!
    I don't know any more about the use of supercritical CO2 than you do. Probably less! But I did come across an article somewhere else which dealt with the prospects of using this form of CO2 on Mars because of the Martian atmosphere being almost pure carbon dioxide.
    I don't think they mentioned concrete in the article I saw but it seems this process you mention could open up a whole new era of tailor-made concrete with different characteristics for different tasks. It would be interesting to experiment with Martian regolith analogue, introducing various contaminants in various concentrations using supercritical CO2, to see what effect it has on the performance of the finished product.
    Who knows what exotic and useful materials might result!

    [My only problem is with what passes for Martian regolith analogue. As many here know, I'm not at all sure about this 'peroxides or superoxides in the soil' hypothesis. I believe this is a left-over from a gradually eroding information paradigm about Mars, which was formulated to explain data which are better explained by Martian microbes.
    It could be dangerous to do experiments with the current crop of soil analogues, come up with certain results, rely on those results, make plans for construction on Mars based on those results, and then find the real Martian soil is quite different!
    Sorry! My mind just went off at a tangent for a while there!!]
                                         smile


The word 'aerobics' came about when the gym instructors got together and said: If we're going to charge $10 an hour, we can't call it Jumping Up and Down.   - Rita Rudner

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#3 2003-08-23 07:42:47

Josh Cryer
Administrator
Registered: 2001-09-29
Posts: 3,830

Re: Supercritical CO2 - Useful technology?

Hmm, Shaun, obviously that's why a good settlement is going to need a nice chemistry lab along with it. This way once we arrive we won't have to worry about whether or not our “one shot only” ideas will work. If the first idea doesn't pan out, try again using a different method.

But Bill, I think it's a wonderful idea, too bad the actual process isn't explained in detail. We need numbers. sad


Some useful links while MER are active. Offical site NASA TV JPL MER2004 Text feed
--------
The amount of solar radiation reaching the surface of the earth totals some 3.9 million exajoules a year.

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#4 2003-08-27 20:43:30

colonist
Member
Registered: 2002-03-23
Posts: 24

Re: Supercritical CO2 - Useful technology?

My company prints a monthly newspaper for the drycleaning industry and I read an article 2-3 months ago on CO2 as the "next miracle drycleaning formula."

From what I read, it seems that the CO2 can be targeted to disolve spesific compounds while leaving simlar ones untouched (organic stains removed whils dyes remain). I am not sure HOW this is done but they seem to have it nailed down prety well. I will see if I can get any info from the next issue of clothesline.

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#5 2003-08-28 07:34:25

Bill White
Member
Registered: 2001-09-09
Posts: 2,114

Re: Supercritical CO2 - Useful technology?

Here is another link to spacedaily.

Magnesium burns and is a useful compenent for solid fuel rocket engines. Supercritical CO2 can readily dissolve magnesium found in Mars regolith and thus easily extract and deposit the metal for later use.

Thus, supercritical CO2 can be used to help build rocket engines and also be used to clean the uniforms of the settlers.

How cool is that?

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#6 2003-08-28 10:54:14

RobertDyck
Moderator
From: Winnipeg, Canada
Registered: 2002-08-20
Posts: 5,995
Website

Re: Supercritical CO2 - Useful technology?

One of my projects is a high fidelity soil simulant. I am also concerned about the accuracy of Martian regolith analogues, so I'm trying to produce one that is very accurate. The superoxides are produced in a very simply way: put the regolith in a chamber that is exposed to exactly the same atmosphere mixture as Mars, freeze it and reduce the pressure to the same as Mars, then expose it to the same UV light as Mars. That does produce superoxides, and the process is an exact duplicate of Mars conditions, so I believe it is accurate. I don't use anything else to create super oxides.

I'm still working with a geologist to perform a CIPW analysis of results from Mars. I'm synthesising results from Viking, Mars Pathfinder, Mars Global Surveyor, and now Mars Odyssey. There are some surprising results; there is so much water found by Odyssey and clay discovered by MGS that the calculations only make sense if the apatite mineral is completely weathered away into clay. That releases all the chlorine as salt instead of incorporated into minerals. That makes the regolith quite salty. To make the numbers balance I also had to introduce a little hematite, which may not seam surprising at first because Mars is so red, but hematite tends to be formed in hot springs. The evidence of water resolves part of that dilemma. I'm still working on the balance of hydrated minerals; their chemical formula is more complicated so it's not as clear how to balance them. I want results that are perfectly consistent with all results from Mars before making the regolith simulant available.

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#7 2003-08-28 13:42:27

Bill White
Member
Registered: 2001-09-09
Posts: 2,114

Re: Supercritical CO2 - Useful technology?

I want results that are perfectly consistent with all results from Mars before making the regolith simulant available

Then, we plant grapes in Robert's soil simulant, make wine and sell it for $500 a bottle to raise money for Mars exploration.

It will probably be lousy wine, but the emotional appeal of "genuine" Marsian wine would be staggering.

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#8 2003-08-28 16:31:03

clark
Member
Registered: 2001-09-20
Posts: 6,265

Re: Supercritical CO2 - Useful technology?

Then, we plant grapes in Robert's soil simulant, make wine and sell it for $500 a bottle to raise money for Mars exploration.

I have a recipe for Marsian 3G.  :laugh:

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#9 2003-08-28 16:51:59

dickbill
Member
Registered: 2002-09-28
Posts: 749

Re: Supercritical CO2 - Useful technology?

The superoxides are produced in a very simply way: put the regolith in a chamber that is exposed to exactly the same atmosphere mixture as Mars

Very interesting. But what do you call Regolith exactly ? I mean, with what do you start : basalts, volcanic stones with added salts or oxydes ?

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#10 2003-08-28 23:51:12

Free Spirit
Member
Registered: 2003-06-12
Posts: 167

Re: Supercritical CO2 - Useful technology?

If the process is as easy as the article mentioned, it seems generating water from the regolith could turn out to be the most beneficial use of hypercritical co2.  It would beat getting out the witching stick to find big reservoirs of water to tap.  Here's the snippet from the article:

Pulling water from rocks will probably have the biggest payoff, at least in the short term, says Debelak. In addition to drinking, "you can split water into hydrogen for fuel, and oxygen for breathing--or as an oxidizer for some sort of engine." Eventually, colonists could set up plants that use CO2 from the martian atmosphere to process hundreds of kilograms of raw material a day.


My people don't call themselves Sioux or Dakota.  We call ourselves Ikce Wicasa, the natural humans, the free, wild, common people.  I am pleased to call myself that.  -Lame Deer

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#11 2018-12-09 18:24:23

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 18,933

Re: Supercritical CO2 - Useful technology?

Just finished fixing topics artifacts....

So getting enough co2 to superheat for a fluid to make materials seems to be quite beneficial

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#12 2018-12-09 19:39:55

knightdepaix
Member
Registered: 2014-07-07
Posts: 236

Re: Supercritical CO2 - Useful technology?

scCO2 is good but how about chemical reduction of carbon dioxide by hydrogen from water splitting to oxalic acid that is a solid. From ethylene glycol, glycolaldehyde, glyoxal, glycolic acid, glyoxylic acid, oxalic acid to two molecules of carbon dioxide, there are six choices of oxidation to be utilized.

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