Home Page

 Canadian Links
   About Us
   Chat
   Events
   In the News
   Newsletter
   Projects

   Regional Contacts
   Montreal Chapter
   Ottawa Chapter
   Toronto Chapter
   Waterloo Chapter
   Vancouver Chapter
   Victoria Chapter

International Mars Society Links

 About Us
   Purpose
   Founding Declaration
   By-Laws
   Chapters
   Task Forces
   Contacts
   Steering Committee

 News & Content
   Bulletins
   Whole Mars Catalog
   Mars News
   MS In the News

 Shopping
   Shop Winnipeg
   Mars Store
   Shop Canada

 Interactive
   New Mars Forum
   Chat Rooms
   Mars Images & Charts
   Mars Toolkit
   Seti@Home

 International Sites
   Australia
   Austria
   Belgium
   France
   Germany
   Ireland
   Japan
   Mexico
   Netherlands
   Poland
   Russia
   San Marino
   South Africa
   Spain
   United Kingdom
   United States
   Other

Plastics
Various plastics can be made from carbon dioxide and hydrogen. Rather than list them all here, proceed to the Plastics page.

Steel wall studs
Galvanised steel wall studs are already used in office buildings. Their advantage over wood is light weight so tall office towers don't have to support heavy partition walls, and fire proof. Steel wall studs are price competitive with wood (I'm not sure which is the cheapest right now) but they don't provide structural support. That support is why they aren't used in homes. On Mars we won't have wood, so steel wall studs would be ideal for partition walls. Just use steel I-beams for structural support. Centre support could be from either steel tele-posts or brick columns. Perhaps the architects would want to use a brick interior partition wall to provide support for the steel floor beams. Brick weight-bearing walls and steel stud partition walls.

Galvanised coating
Steel wall studs are galvanised to prevent rust. Our oxygen atmosphere, especially with moisture, will cause steel to rust. Steel is just dipped in molten zinc to coat it. Sojourner data did not list any zinc. Nickel, Aluminum or Chromium could be used; they have higher melting temperatures but you use what is available.

Chrome plated wall studs with plastic floors is beginning to sound like an old science fiction set.

Iron, Fibreglass & Gypsum
There is certainly a lot of iron in Martian soil. Sojourner data showed Martial soil to contain 14.1-16.6% iron. Low carbon steel is used for construction because it is strong and its ductility will cause dents from impact instead of breaking. Pure iron is even better for some applications because it is less prone to breaking, though more prone to bending. Pure iron is also slower to rust than low carbon steel. Why do I say all this? There isn't any carbon in Martian soil, we would have to include carbon captured from the air. Mild steel (low carbon) is used today on Earth because the process of smelting mixes coke (coal with sulphur removed) with the ore, and that makes separating carbon out of the iron hard. Why separate it out if you don't have to? It may be more practical on Mars to use iron.

If we have to smelt it to make iron or mild steel then perhaps we should smelt the slag as well to convert it into useful products. Sojourner data showed 39.8-42.2% silicon dioxide. Glass is primarily silica with soda-lime added to reduce the fusion temperature and as a stabilizer. Silica is SiO₂, soda is Na₂CO₃, lime is CaO. Fibreglass is an excellent thermal insulation. Do we really need to add soda just for fibreglass insulation? A less refined glass may do.

Gypsum is used to make wall board. It is used on Earth because it can just be dug up, dissolved in water, poured onto paper, covered with a top layer of paper, then baked to get the water out. The result is then just cut into 4'x8' sheets and paper tape covers the edges. We won't have gypsum readily sitting on the surface for us. Gypsum is CaSO₄•H₂O. 5.4-6.4% of Martian soil is lime [CaO], 5.2-6.8% superoxidised Sulphur [SO₃]. We could make Gypsum. Is there a better material? If we just spread Martian soil between paper layers and bake it, it will be as hard as brick. Basically you would have a flat, thin brick. It would be heavy and a sheet that thin may break from its own weight. Is there something better than gypsum for wall board, or should we just make gypsum? What would be the chemical process to make gypsum from slag?

Paper on Earth is made from wood pulp because wood is available and cheap. Hemp paper is stronger and hemp grows much more quickly. Do we really need paper for the covering for wall board? We would want something for an inner wall. Mars is cold. A brick exterior wall would be structurally sound, but you want thermal insulation between the wall and the interior space. Fibreglass can be the insulation, and steel studs can form the frame, but then what is the interior wall? We may want to grow hemp just for wall board.

Fibreglass
I did some more research on fibreglass. It is made by jetting molten glass through tiny heated holes into high-speed air streams. It is made from sand (SiO₂), sodium carbonate (Na₂CO₃), and limestone (CaCO₃). Since glass for window panes and jars is made with lime (CaO) instead of limestone, I believe this would be an even better quality glass without requiring manufacture of synthetic limestone on Mars. Fibreglass is held together with phenol-formaldehyde and urea-formaldehyde resins. Yellow fibreglass uses urea-formaldehyde and pink uses phenol-formaldehyde.

Soda is sodium carbonate. That is a salt. If sodium exists in Martian regolith as an oxide or super oxide, it can be converted into soda very easily. Just dissolve the sodium oxide in water, then bubble carbon dioxide through the water. Oxygen will be released and soda created. Boil down the result to extract the water and you have soda.

If calcium exists in Martian regolith as an oxide, that is already lime.

Formaldehyde (HCHO) is made by combustion of hydrogen with carbon monoxide. Phenol (C₆H₅OH) in dilute form is carbolic acid, used as a disinfectant. Phenol can be made from heating wood (18-20% conversion, National Renewable Energy Laboratory). Urea is CO(NH₂)₂. Urea is the primary chemical in urine, so the astronauts themselves produce this. Yellow fibreglass brings new meaning to recycling.

As Robert Zubrin pointed out in The Case For Mars, page 182, carbon monoxide can be produced with the reverse water-gas shift (RWGS). H₂ + CO₂ → H₂O + CO

Fibreglass can also be made with an acrylic binder (Environmental Building News). This form is off-white.

Charcoal
I said baking wood would form phenol oil. It is actually impure, but once it is combined with formaldehyde into a polymer, that polymer binds all the impurities together. Click the link for NREL for more details. The process of heating wood to produce phenol oil is called pyrolysis. I think the remainder of the wood (80-82% by weight) is converted into smoke and charcoal. Charcoal is almost pure carbon. That could be used for other purposes, but we would still need wood as a starting point. Furthermore, to make charcoal you have to use hardwood.

Gypsum
My chemist friend tells me that calcium sulphide is also a salt. CaSO₄•H₂O is gypsum. If calcium oxide is dissolved in water together with sulphur oxide, the two will combine to form gypsum and release oxygen. Then boil down the solution to extract water and concentrate the gypsum. This is similar to the process to create soda.

Concrete
Concrete is made by mixing sand and gravel with cement and water, then allowing the mixture to harden. Geologists would classify concrete as an aggregate of stone held in a matrix of calcium carbonate. Ancient Romans mixed lime with volcanic ash to make cement. Portland cement was originally made in 1824 by heating a mixture of limestone and clay in a kiln then pulverising the resulting material. One source says "Portland cement is made by heating substances containing lime, silica, alumina, and iron oxide, with gypsum added during the grinding process". Does that remind you of anything? No wonder Martian regolith makes such good bricks.

Another source says portland cements are mixtures of tricalcium silicate (3CaO•SiO₂), tricalcium aluminate (3CaO•Al₂O₃), and dicalcium silicate (2CaO•SiO₂), in varying proportions, together with small amounts of magnesium and iron compounds. Gypsum is often added to slow the hardening process. Heating is usually accomplished in rotating kilns, slightly tilted from the horizontal, and the raw material is introduced at the upper end, either in the form of a dry rock powder or as a wet paste composed of ground-up rock and water. As the charge progresses down through the kiln, it is dried and heated by the hot gases from a flame at the lower end. As it comes nearer the flame, carbon dioxide is driven off, and in the area of the flame itself the charge is fused at temperatures between 1540° and 1600°C (2800° and 2900°F). The material takes approximately 6 hours to pass from one end of the kiln to the other. After it leaves the kiln, the clinker is cooled quickly and ground, and then conveyed by a blower to packing machinery or storage silos. The amount thus produced is so fine in texture that 90% or more of its particles will pass through a sieve with 6200 openings per sq cm (40,000 per sq in).

Rapid-hardening cements, sometimes called high-early-strength cements, are made by increasing the proportion of tricalcium silicate or by finer grinding, so that up to 99.5% will pass through a screen with 16,370 openings per sq cm (105,625 per sq in). Some of these cements will harden as much in a day as ordinary cement does in a month. They produce much heat during hydration, however, which makes them unsuitable for large structures where such heat may cause cracks. Rapid hardening cement is also used in Canada during the winter because it produces heat. By covering the form with insulation, the cement will remain warm long enough to set. This feature will be useful in the cold of Mars. Where concrete work must be exposed to alkaline conditions, which attack concretes made with ordinary portland cement, resistant cements with a low aluminum content are generally employed. Mars regolith is alkali. The article does not give the exact proportions of the constituents. It does say cements for use under salt water may contain as much as 5% iron oxide, so that implies other cement mixtures have less.

Concrete would make excellent foundations and mortar for bricks.

Smelting iron
Carbon monoxide combines with iron oxides in the ore to produce metallic iron. This is the basic chemical reaction in the blast furnace; it has the equation: Fe₂O₃ + 3CO → 3CO₂ + 2Fe. The usual way of producing steel has been to produce pig iron first in a blast furnace, then convert it into steel in a Bassemer converter. The Bassemer literally burns off impurities by injecting large quantities of oxygen. The direct method produces steel from ore in a single step, and produces steel or iron of much higher purity than pig iron. In this process iron ore and coke are mixed in a revolving kiln and heated to a temperature of about 950°C (1740°F). Carbon monoxide is given off from the heated coke just as in the blast furnace and reduces the oxides of the ore to metallic iron. We don't have coal to make coke on Mars, but we don't have an oxygen atmosphere either. Carbon monoxide could be introduced to ore directly. Since heat wouldn't be produced by burning coke, heat would have to be introduced electrically. This can be done by either lowering an electrode close to the steel to produce an arc, or using a heating coil. An electrode requires electrically conductive ore, and the electrode erodes, so a coil is preferred. The Martian furnace would then combine the features of the Direct method with an Electric-Furnace.

Once steel is made, it must be worked to refine its crystalline structure. In hot rolling, the bright-red hot ingot is passed between a series of pairs of metal rollers that squeeze it to the desired size and shape. Rollers used to produce I-beams are grooved to give the required shape.

Carbonyl process to extract iron
Using iron carbonyl production, the iron is drawn off as a carbonyl vapor. A mixture containing iron is heated to 120°C with CO and the pressure is raised a bar or two. The gas is drawn off leaving the SiO₂, CaO, etc as they were. The gas is depressurised and cooled with the Fe(CO)₅ condensing out for our use. Iron carbonyl production Fe + 5CO → Fe(CO)₅ 120°C liquid, vaporises at modest pressures. Iron deposition from iron carbonyl Fe(CO)₅ → Fe + 5CO at 200°C.

At first glance this is particularly useful for Mars due to its low energy requirement, and the fact that it leaves the SiO₂, CaO, etc suitable for further processing or as a soil. However, the carbonyl process requires metalic iron as its starting point; iron in regolith is an oxide. That still requires smelting to reduce it, and smelting temperature will convert regolith into slag.

Smelting aluminum
On Earth, alumina is separated from bauxite ore by crushing it, then dissolving in caustic soda (NaOH) at 145°C (300°F) and 50 psi for over 30 minutes. Then more caustic soda is added. The result is moved to a flash tank to reduce pressure and recover heat. That is moved to a settling tank. After letting the solids settle out, the result is filtered. The remaining red mud is washed to recover caustic soda and alumina. Alumina is then precipitated out of solution by crystallising, using alumina hydrate seed crystals. Alumina hydrate is then "calcinated" by heating it to 1,100°C (2,000°F) to remove water, converting it to alumina.

To remove the oxygen, aluminum requires electricity run through it, but alumina itself does not conduct electricity. Alumina is usually dissolved in molten cryolite because that conducts electricity. Cryolite is a brittle translucent rock with the formula Na₃AlF. Some of the sodium from cryolite is lost by combining with oxygen from the alumina, leaving aluminum fluoride (AlF); this is still conductive. As the reduction process takes place, the aluminum sinks to the bottom of the pot while the oxygen gas rises to the surface to be drawn off. A carbon anode is dipped into the aluminum fluoride to complete the electrical connection. Carbon from the anode will combine with some of the oxygen to form carbon dioxide. Carbon is therefor lost during the process.

Martian regolith analysed by Sojourner did not list any fluorine. The process looses very little cryolite, do we just ship cryolite from Earth?

Smelting titanium
Rutile ore (TiO₂) is reacted with chlorine and coke (carbon) to produce titanium tetrachloride (TiCl₄). The coke is used just for heat, so it could be replaced by an electric heating coil. This is then reacted with magnesium. The result is called titanium sponge; this is commercially pure titanium. The sponge is separated from magnesium and magnesium-chloride by the Vacuum Distillation Process or the older Kroll-leach process. The MgCl₂ is separated back into magnesium and chlorine.

Ilmenite ore (TiFeO₃) is more complicated to smelt. First grind the mineral and mix it with potassium carbonate (K₂CO₃) and aqueous hydrofluoric acid (HF) to yield potassium fluorotitanate (K₂TiF₆). The fluorotitanate is extracted with hot water and decomposed with ammonia (NH₃). The resulting ammoniacal hydrated oxide, when ignited in a platinum vessel, yields titanium dioxide, TiO₂. Then smelt the titanium dioxide as you would rutile.

Ilmenite can also be reduced with hydrogen to produce 88-92% pure TiO₂. Heat ilmenite/hydrogen to 700-1015ºC. Adding potassium chloride [KCl] increases the reaction 100-170%. At temperatures over 807ºC potassium carbonate [K₂CO₃] instead of KCl increases the reaction 164-276% over non-catalyzed. Over 900ºC TiO₂ will start to reduce to metallic titanium. TiFeO₃ + H₂ → Fe + TiO₂ + H₂O Then leach the result to remove metalic iron. Finally, electrolysize the water into hydrogen and oxygen.

Sphene is another mineral of titanium. (CaO•TiO₂•SiO₂) I suspect it can be processed the same way as ilmenite. I guess the first question is to find what mineral form exists on Mars. Samples from the Moon contain titanium as ilmenite, but Mars has significant quantities of silicon dioxide and calcium oxide, so Mars may have sphene.

Titanium may be a material we don't want to use, at least at first. Processing ilmenite requires fluorine, which was not found by sojourner, and a platinum reactor vessel. If we do find fluorine we may want to use that for cryolite to smelt aluminum.

Terra cotta floor tiles
I saw a TV documentary of a reconstruction of a Roman bath. They used 3'x3' floor tiles supported on brick columns at the tile corners. The idea was to leave a space beneath the floor for the Roman heating system, but that does show these tiles can be used without a subfloor. The tiles have to be given time to cure, and the recreationists were impatient. To compensate they ringed each tile with steel.

If baked Martian regolith produces bricks, perhaps simply forming a thin flat form could produce terra cotta tiles for the floor. A steel lattice truss is lighter and uses less material than an I-beam. Perhaps small steel trusses to replace floor joists to hold the terra cotta floor tiles, then either a large truss or I-beam as the main floor beam. The tiles could be moulded with a small tongue in each side to match a groove in the joist, and one end could be moulded with a tongue to slide under the next tile to form a lap joint. The joints between tiles could be filled with a grout of thinly mixed mortar: Portland cement with gypsum instead of sand or gravel.

Granite counter top
Since we are getting into some rather nice materials, and using native Mars materials for construction, how about cutting granite slabs for counter tops? A polished granite counter is one of the luxurious materials to make an up-scale home. Igneous rock will certainly be on Mars, granite may be one of the easiest materials to find. Granite is nonporous so it doesn't stain, and it will not burn or scorch from hot kitchen pots or pans. It is chemically non-reactive so it would also make a great chemistry workbench top.

UV control (PVB)
What is the radiation on Mars? If it is just ultraviolet, then we could use polyvinyl butyral (PVB). That is a plastic sheet that can be applied to windows which absorbs 99% of UV. Some brands are Saflex, Butacite and Santotac MRS. UV wavelengths less than 300nm will be blocked by normal glass, although 300-400nm (used for tanning) will get through.

PVB is a plastic. I could look up some processes of making it, but let's just say it is another polymer.

Heat Mirror
The "Heat Mirror" coating currently used in high efficiency windows is a layer of silver-oxide either impregnated directly into the glass, or a plastic coating. The silver-oxide is only a few hundred atoms thick. It reflects long wave IR, such as radiant heat from warm objects, but transmits visible light and short wave IR, such as the heat part of sunlight. This would help warm the dome by trapping radiant heat in. This metal layer should also block any X-rays that make it through Mars' atmosphere. Blocking 99% of UV would extend life of plastics more than 10 times. Protecting the dome from particle radiation is more difficult. The first question is exactly how much gets through the Martian atmosphere to the surface. We will have to protect colonists from that radiation.