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This topic is available for NewMars members who might wish to collect links to articles or images about smelting metals or other material using solar power.
https://www.weforum.org/stories/2024/05 … -smelting/
The lead off article at the link above is about research that might lead to use in industry.
Smelting metals or other materials using solar power is likely to be investigated thoroughly for space applications.
2025/03/25 The title was extended to incorporate simple melting of material, for shipment, as a companion to smelting, which would most likely be performed at facilities near to Earth. Melting material for shipment is a technique that might seem attractive at the asteroid itself, where the infrastructure to support smelting would not be available.
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This post is reserved for an index to posts that may be contributed by NewMars members over time.
Index:
Post #3: Calliban - Description of plant to reduce iron oxide
https://newmars.com/forums/viewtopic.ph … 97#p230397
Post #4: Calliban: Dissociation of CO2 at 1600 Celsius
https://newmars.com/forums/viewtopic.ph … 99#p230399
Post #5: Calliban - a batch process for reducing ore using pressure
http://newmars.com/forums/viewtopic.php … 06#p230406
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This could be useful.
https://pubs.rsc.org/en/content/article … c6cc08801e
CO2 starts to dissociate into CO and O2 at temperatures as low as 1200°C. This is within reach of concentrated solar power systems. To be useful, we would need ceramic materials with sufficient porosity to allow CO to pass through them, but remaining non-porous to O2. It must also be non-reactive to CO. Aluminium oxide may be a good candidate. Hot CO will reduce iron (III) oxide to iron and CO2 at temperatures greater than 800°C.
Fe2O3 + 3CO = 2Fe + 3CO2.
The CO2 can be recycled. A well designed plant could produce crude iron, electricity and process heat. Iron powder can then be converted into steel using an electric furnace.
Last edited by Calliban (2025-03-18 07:40:38)
"Plan and prepare for every possibility, and you will never act. It is nobler to have courage as we stumble into half the things we fear than to analyse every possible obstacle and begin nothing. Great things are achieved by embracing great dangers."
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This reference discusses CO2 dissociation in ceria tubes at temperatures of 1600°C.
https://www.sciencedirect.com/science/a … 4721016119
This might be tough to achieve with concentrated solar heat. The concentration factor must be extremely high.
"Plan and prepare for every possibility, and you will never act. It is nobler to have courage as we stumble into half the things we fear than to analyse every possible obstacle and begin nothing. Great things are achieved by embracing great dangers."
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At atmospheric pressure, temperatures of at least 800°C are needed for the reaction between hydrogen and iron oxide to proceed at reasonable speed. However, at high pressure, the reaction rate is favourable even at relatively low temperatures of a few hundred C.
https://pmc.ncbi.nlm.nih.gov/articles/PMC9417644/
We still need a source of reducing gas: CO, H2 or CH4. But high pressure reduces the temperature needed to levels that are more easily provided by solar thermal. In fact, entirely mechanical energy can be used to drive the process.
The strength of steels do not decline significantly between room temperature and 400°C. After that, tensile strength declines rapidly as temperature increases, with a 50% loss of strength between 500 and 550°C. If solar heat can be provided at a temperature between 300-400°C, then iron reduction may be easier to achieve in a closed pressure vessel.
This would be a batch process. A bin containing finely crushed iron oxide would be loaded in. The pressure vessel would be sealed and reducing gas would be pumped into the vessel up to a pressure of 200 - 500bar. The compression itself would generate enough heat to bring the contents of the vessel up to the required temperature. After a predetermined cook time, the vessel would be drained of gas and the bin containing the partially reduced iron oxide would be removed. Another bin would be loaded into the vessel and the process begins again. Once removed from the vessel, the bin would be emptied. Its contents would crushed and reduced iron powder would be removed using electromagnets. The iron powder can then be turned into steel in an electric arc furnace.
Last edited by Calliban (2025-03-18 12:03:35)
"Plan and prepare for every possibility, and you will never act. It is nobler to have courage as we stumble into half the things we fear than to analyse every possible obstacle and begin nothing. Great things are achieved by embracing great dangers."
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This post is about smelting in microgravity using solar energy.
The subject arises out of work going on to investigate kbd512's idea for a solar powered propulsion system for a space vessel.
A byproduct of the investigation is discovery of a concept for collecting solar power in space. A feature of the system is the ability to direct collected solar energy with precision, since the photons are fed into optical fibers.
I asked Google's Gemini to see what it could find of research that might have been done at the ISS or elsewhere:
Hello Gemini! Thanks for your help with previous questions! Today's question is about smelting solid material in space in microgravity using solar radiation. It is entirely possible that scientists have performed such tests in the decades of human space flight. Can you find any reports of such research?
It's true that the concept of smelting materials in space, particularly using solar radiation and in microgravity, has been a subject of research and consideration. Here's a breakdown of what I found:
Key Considerations and Research Areas:
Microgravity's Influence:
Microgravity significantly alters the behavior of molten materials. It eliminates convection currents and sedimentation, which are crucial in traditional Earth-based smelting.This opens possibilities for creating materials with unique properties, but also presents challenges in controlling the process.
Solar Radiation as a Heat Source:
The abundant solar radiation in space makes it a promising energy source for smelting. Concentrating sunlight could provide the necessary heat for melting and processing materials.
However, controlling and focusing this energy precisely is essential.
Materials Science in Microgravity:
Research has focused on understanding how materials behave when melted and solidified in microgravity. Experiments have been conducted on the International Space Station (ISS) to study these processes.
Facilities like the Material Science Laboratory Electromagnetic Levitator (MSL-EML) on the ISS are used to investigate the melting and solidification properties of various materials.
In-Space Manufacturing (ISM):
The broader concept of ISM encompasses smelting and other material processing techniques.
ISM aims to utilize space resources for manufacturing products, both for use in space and potentially for return to Earth.This includes the idea of using asteroid resources, which would require smelting and refining processes.
Challenges:
Controlling molten materials in microgravity.
Efficiently concentrating and utilizing solar radiation.
Managing the waste products of smelting.
The logistical challenges of transporting and processing materials in space.In summary:
While large-scale smelting operations in space are still in the developmental stage, significant research has been conducted to understand the fundamental processes involved. Space based material processing is a growing field of study, and is vital to future long term space exploration.
Scientists Remotely Make and Melt 'Unusual' Zero-Gravity Glass in Space
Source icon
www.usglassmag.com
Vibration-induced morphological evolution of a melting solid under microgravity | Journal of Fluid Mechanics - Cambridge University Press & AssessmentSource icon
www.cambridge.org
Advanced Manufacturing and Materials - ISS National LabSource icon
issnationallab.org
Solar thermal energy - WikipediaSource icon
en.wikipedia.org
6 NASA Experiments on Materials, Benefitting Space and EarthSource icon
science.nasa.gov
I note that we have another topic about smelting. That one was created by JoshNH4H, and it starts out focused upon aluminum.
Since there is gravity on the Moon, smelting processes developed on Earth that require gravity would work.
The presence of high quality vacuum might be advantageous.
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The photon collection system under consideration for solar powered propulsion is currently imagined as capable of delivering 40 MW with precision. Aside from serving the needs for propulsion, that capability would be potentially available for processing material, such as might be found on or in an asteroid.
This topic is available for NewMars members who might have time to think about how solar power at that level might be harnessed to process material collected from an asteroid.
At the very least, melting a loose quantity of material into a liquid would make it easier to manipulate after it solidifies.
Aside from that, perhaps there is something useful that could be done with hot material?
The absence of gravity means the liquid will not settle as it cools.
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Waste materials from ore processing will be mostly silicate rich slag. A few years back on this forum, we discussed the production of basalt fibres for tensile applications. The fibres are as strong as maraging steel and weigh less than half as much. Melting basalt is considerably less energy intensive than smelting steel, because the temperatures involved are more modest (1200°C vs 1600) and chemical reduction is not necessary. We are melting the material and not chemically reducing it. If we have enough energy to melt silica rich slags, then the liklihood is that we would find uses for these materials.
"Plan and prepare for every possibility, and you will never act. It is nobler to have courage as we stumble into half the things we fear than to analyse every possible obstacle and begin nothing. Great things are achieved by embracing great dangers."
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For Calliban re #8
First, thank you for giving this topic your attention!
If you have a bit more time, please think about how we humans might make use of concentrated sunlight if we can put a facility with the feature next to an asteroid, such as 2024 YR4 that will be passing Earth in 2028. We (humans) have time to deploy one or more probes to visit that asteroid, and at least one of them might be designed to make a serious investigation of mining potential for this particular rubble pile.
I recognize that "smelting" is distinctly different from "melting".
My guess is that all that a simple solar heating device can do is to melt material that might be collected from an asteroid. Certainly the spectrographic records made during the melting operation should add value to the enterprise, because each melt could be tagged for value, when it is shipped back to Earth in a slow but reliable process such as solar sailing.
We have at least one NewMars member who is skeptical of the potential value of the contents of a non-metallic asteroid, but I think that ** any ** atom that is in LEO or a similar location outside a gravitation field will be quite valuable indeed.
In any case, making a spectrographic record of the contents of a melt would insure that whatever materials are present are identified, and perhaps even quantities can be determined.
Actual smelting could (presumably) be done at LEO or another suitable location. On the ** other ** hand, mere melting of materials found in an asteroid will release gases that may be present, and if those are not captured during the melt they would be difficult to recover later.
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