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Author Topic: Getting breathable oxygen from ilmenite on the moon  (Read 4814 times)

Offline njrich

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Please, can someone tell me what the '03' is in ilmenite (FeTiO3)?
I recently read an article that described getting breathable oxygen from ilmenite found on the moon. As a lay person I assumed the O3 at the end of FeTiO3 was oxygen, like O2, so I looked up O3 to see what it was and it turned out that O3 was ozone, which is unstable and converts to O2 and then O1 in a short period of time under the right circumstances. So I thought I understood this and posted the same on FB because it seemed intersting (air on the moon and all) when one of my FB friends says I got it all wrong and that the O3 isn't ozone, but rather it's 3 oxygen atoms?  He didn't or wouldn't elaborate further on it and now I'm stuck trying to understand it. In lay terms, can someone explain it to me properly?  Much thanks.
- Rich 


 

Offline CliffordK

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Re: Getting breathable oxygen from ilmenite on the moon
« Reply #1 on: 13/05/2012 18:41:25 »
Many rocks in Earth's crust (as well as on the Moon and Mars) contain large amounts of oxygen as oxides. 

In the case of FeTiO3, there are in fact 3 oxygen atoms for each Iron & Titanium atoms.

When writing chemical formulas, in some cases one might highlight specific structures, such as an alcohol group (OH) in ethanol, C2H5OH, but generally one just counts the number of each type of atom.

So, in the case of FeTiO3, for every 2 molecules of FeTiO3, you would get 3 O2 molecules back.  Looking at the crystal, the atoms are more or less evenly distributed around through the crystal.

http://www.computescotland.com/liminite-gets-the-spotlight-from-argonne-2792.php


I believe in the process of smelting, the oxide ores are often heated with either carbon, or carbon monoxide, which then forms Carbon Dioxide (CO2), plus the reduced metal.  You would then need to convert the CO2 back into oxygen and carbon, perhaps using an organic process + water.  However, in some cases, one can smelt with H2 Hydrogen gas, in which case water (H2O) would be formed.

Incidentally, on the Space Station, Oxygen is usually shipped and stored as water (H2O) due to the ease of handling.  Electrolysis is used to form Oxygen (O2) + Hydrogen (H2).  The excess Hydrogen is then discarded.
 

Offline damocles

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Re: Getting breathable oxygen from ilmenite on the moon
« Reply #2 on: 13/05/2012 21:56:04 »
CliffordK's post above is a pretty good answer. There are just two points where I think it needs a slight amendment:

1. Ilmenite does not have "molecules" of FeTiO3. It is instead a "network compound" where the atoms are all bonded together in a huge (ideally and potentially infinite) lattice. This is clearly shown in the structure diagram in the post above.

2. While carbon smelting can be used to reduce most oxides to the parent metal, titanium is an exceptional metal that holds onto its oxygen very tightly indeed. When ilmenite is carbon smelted, it is possible that metallic iron could form, and possibly a lower oxide of titanium than its preferred TiO2. TiO and Ti2O3 are both well known and well characterized oxides. But somewhere in the region of 35 to 70 percent of the oxygen is incapable of being transferred to form CO in a direct smelting process.

Titanium is one of the hardest metals to win from its ores. Traditionally it has been done using the Kroll process.

http://www.madehow.com/Volume-7/Titanium.html#b

However, recently a specialized electrolytic method has been discovered, and it is likely that the ilmenite reduction technology that is envisaged to produce oxygen will use electrolysis.

http://www.canadianminingnews.com/titaniumrevolution.htm
 

Offline Geezer

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Re: Getting breathable oxygen from ilmenite on the moon
« Reply #3 on: 13/05/2012 22:12:40 »
Fascinating! No wonder it's expensive.
 

Offline imatfaal

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Re: Getting breathable oxygen from ilmenite on the moon
« Reply #4 on: 14/05/2012 15:22:10 »
Fascinating! No wonder it's expensive.

Agree - thanks Damocles.   I also remember watching a light-weight tv documentary (at Oakley - the sunglasses people) talking about the difficulty of working Titanium.  So expensive to obtain and expensive to work
 

Offline njrich

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Re: Getting breathable oxygen from ilmenite on the moon
« Reply #5 on: 15/05/2012 07:18:13 »
...So, in the case of FeTiO3, for every 2 molecules of FeTiO3, you would get 3 O2 molecules back. 

Clarification needed please:

1) So the O3 is actually 3 molecules of O2?
2) If yes, then are these O2 molecules the same as what we would find in the air we breathe or is this some other form of O2?
 

Offline Mazurka

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Re: Getting breathable oxygen from ilmenite on the moon
« Reply #6 on: 15/05/2012 08:56:18 »
No, 3 atoms of oxygen.

If released from the mineral this oxygen could form the stable molecule O2, which we breathe or in certain circumstances it could form the unstable compound O3 (aka Ozone) which would in due course break down into one O2 molecule and one oxygen atom.  A single oxygen atom would rapidly join with another single oxygen atom to form O2

Imagine FeTiO3as a lego brick, each brick contains exactly one iron, one titanium and three oxygen atoms.  The lump of Ilmenite (that you could process to extract oxygen and titanium) is many of these lego bricks stuck together.
« Last Edit: 15/05/2012 08:59:48 by Mazurka »
 

Offline CliffordK

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Re: Getting breathable oxygen from ilmenite on the moon
« Reply #7 on: 15/05/2012 10:48:03 »
...So, in the case of FeTiO3, for every 2 molecules of FeTiO3, you would get 3 O2 molecules back. 
Clarification needed please:
1) So the O3 is actually 3 molecules of O2?
2) If yes, then are these O2 molecules the same as what we would find in the air we breathe or is this some other form of O2?
Ok, I think you are getting a little stuck on the notation.

When reading a chemical formula.

3(2H218O)

The first number (3) in normal print is the number of molecules (in the part of the equation).  You can add or subtract to this to balance your equation without affecting the chemical formula.
The second number (2) as a superscript is a indication of the isotope, and is a count of the atomic particles in the nucleus (protons + neutrons).  This would be invariable with any chemical reactions.  It modifies the following letter (H) for Hydrogen, or in this case Deuterium with one proton and one neutron.
The third number (2 again) in a subscript tells the number of hydrogen atoms, also modifying the preceding H.
The fourth number (18) in superscript, also indicates the oxygen isotope, modifying the following O.  8 protons for oxygen, 10 neutrons for a sum of 18.  Again, it would not change without a nuclear reaction.

In your case with FeTiO3, you merely have 3 oxygen atoms for every Iron and Titanium atom.

Oxygen can exist in several forms.

O : Free radical.  It is extremely reactive, and readily combines with other oxygen atoms, or many other things it comes in contact with.
O2 : Generally stable.  This dimer form of most of the oxygen we find in our air.
O3 : Ozone, a trimer. 

So, when conducting chemical reactions that generate oxygen, it will generally spontaneously combine to form O2, breathable oxygen.

For example, if one does electrolysis of water (H2O), the end product would be Hydrogen dimer (H2), and Oxygen dimer (O2) in ratios of 2:1 Hydrogen to Oxygen.  You never really think of a single molecule, but rather a reaction of a quantity of a substance, with 6.022×1023molecules per mole.

In some cases, such as Carbon Dioxide (CO2), the two oxygen atoms are located on opposite sides of the molecule  O=C=O.  Yet, in plants, the conjunction with water (H2O), the carbon is extracted to form various hydrocarbons, and the oxygen from both the water and the carbon dioxide is formed into dimers (O2), and released.

When balancing a chemical equation, one just has to make sure the number of atoms on each side of the equation are the same.

For example, the formation of Ethane from water and carbon dioxide.

a(CO2) + b(H2O) --> c(O2) + d(C2H6)

One just finds the number (a,b,c,d) of molecules to give one the same number of atoms on each side of the equation.
Since Carbon only exists on one side of the equation, one starts with those.  If d=1, then "a" must be equal to 2.

So, now one has 6 Hydrogen atoms on the right, so one must begin with 6 hydrogen atoms (from 3 water molecules) on the left.

one now has:
2CO2 + 3H2O --> c(O2) + C2H6

One begins with 7 oxygen atoms on the left, so one must have 7 atoms on the right, or 3.5 oxygen O2 molecules.

To get rid of fractions, one multiplies the whole equation by 2 to get:

4CO2 + 6H2O --> 7O2 + 2C2H6

There are some reactions where a functional group such as a carboxylic acid will be preserved, especially in biologic reactions.  However, this is not the case in the Iron Titanium Oxide reaction.

It is quite possible that high temperature and electric arc processes would cause the creation of some ozone.  However, ozone can be metabolized by some orgainisms, and will readily decompose back to O2 oxygen with UV light, or under high temperatures, so the formation of some ozone wouldn't be the end of the world.  On the moon, there is plenty of UV to destroy ozone, in fact, one might desire some ozone in the sunshade.
 

Offline njrich

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Re: Getting breathable oxygen from ilmenite on the moon
« Reply #8 on: 15/05/2012 18:48:28 »
So we're dealing with 3 single atoms of oxygen that are bonded to the Fe & Ti making it an FeTiO3 molecule and if those oxygen atoms are released from the mineral by some process, electrolysis or otherwise, they could form either the O2 or O3 molecule by joining with one another, with the understanding that if the conditions were right and they did form an O3 molecule it wouldn't last long because as such it is unstable. Likewise they wouldn't remain as free radicals if there is something nearby to bond with, such as another oxygen atom, which is a virtual given; so an oxygen atom would basically join with another oxygen atom to form an O2 molecule and become usable as such. Yes? 
* Please say yes, my under-educated brain is starting to hurt. :o)
« Last Edit: 15/05/2012 18:50:33 by njrich »
 

Offline CliffordK

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Re: Getting breathable oxygen from ilmenite on the moon
« Reply #9 on: 15/05/2012 19:27:27 »
Yes,
That is a good summary.
 

Offline njrich

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Re: Getting breathable oxygen from ilmenite on the moon
« Reply #10 on: 15/05/2012 23:15:17 »
Thank you CliffordK and everyone else for pitching in. Much thanks!

- Rich
 

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Re: Getting breathable oxygen from ilmenite on the moon
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