4 ms·

A Quartz Thermal Trap Harnessed the Sun–and Is About to Change Smelting Forever

badcppdev 2y ago
Peer review paper: https://www.cell.com/device/fulltext/S2666-9986(24)00235-7 https://www.cell.com/device/fulltext/S2666-9986(24)00235-7 Executive Summary: Solar heater that can work at temperatures close to 1000C by using semi-opaque materials to absorb solar energy and minimise radiative losses. Not even a proof of concept of an improved smelter. Article text in PopMech is exaggeration of paper and headline is a further exaggeration on top of that.
- deleted 2y ago
  [deleted]
- mannykannot 2y ago
  Ah - a greenhouse that can almost melt copper, though I think you need a mirror to get the "135 suns" input radiation.
- scld 2y ago
  The paper itself mentions the usefulness of the 1000C threshold: Solar process heat at above 1,000°C can decarbonize key industrial applications such as cement manufacturing and metallurgical extraction. The article is just running with that theme.
  - jcranmer 2y ago
    > decarbonize key industrial applications such as cement manufacturing and metallurgical extraction ... so what's the reducing agent, if not carbon?
    - floatrock 2y ago
      Can you explain the chemistry pieces vs. the thermal inputs pieces?
      - jcranmer 2y ago
        The main tasks in converting iron ore to steel is as follows: reduce the iron (which requires a redox reaction), drive out existing impurities (both other metals present in the ore, such as magnesium or aluminum, and other nonmetals like sulfur or phosphorous), and introduce new ones (predominantly, uh, carbon). Note that these don't necessarily all occur at the same time, in the same furnace (steelmaking is a multistep process). These processes require the necessary chemical reagents to cause the necessary chemical reactions to occur. There are multiple roles for heat. Most notably, most of the necessary chemical reactions require high heat to occur at a time. Furthermore, outright melting gives the advantage that impurities tend to sort themselves by density, and your impurities are typically less dense than your main metal (i.e., the slag will float on top of the molten iron). There's also the advantage that high heat can make volatile impurities (e.g., sulfur dioxide) boil out. Historically, the reducing agent was largely charcoal, where you burn the wood in oxygen-poor environment to produce high purity carbon-rich material. The industrial revolution replaced charcoal with coke, where you burn coal in oxygen-poor environment to produce high purity carbon-rich material. In both cases, the furnace converts the fuel largely into carbon monoxide, which is the main actual reducing agent in contact with the iron (whereupon it forms carbon dioxide). The decarbonization assumption has been to replace carbon with hydrogen gas, but as far as I'm aware, hydrogen-based reduction furnaces have only existed in pilot plant form.
    - pfdietz 2y ago
      There's a proposed entirely-thermal iron reduction process that uses sodium as the reducing agent. This produces sodium oxide, which apparently can be decomposed back to sodium and oxygen by vigorous heating. I have my doubts about the overall feasibility of this scheme, but it doesn't involve any electrical energy input.
    - deleted 2y ago
      [deleted]
squeegee_scream 2y ago
> Fighting against climate change means building, whether that’s large solar arrays, sprawling wind farms, or powerful fission reactors Can we, maybe, consider using fewer resources? Are we past the point of imagining that we could possibly get by with a sustainable lifestyle?
- jajko 2y ago
  Not with electric cars slowly coming, our current infra at its max here in Switzerland ain't enough for any serious mass electrification. They dwarf all combined electricity usage by huge margin. And somebody has to generate all of it.
  - smallerfish 2y ago
    You have a source on that? Sounds a lot like oil company fud. Couple of results from the top 5 when searching for this: https://www.scientificamerican.com/article/why-electric-vehicles-wont-break-the-grid/ https://www.scientificamerican.com/article/why-electric-vehi... https://www.virta.global/blog/myth-buster-electric-vehicles-will-overload-the-power-grid https://www.virta.global/blog/myth-buster-electric-vehicles-...
    - jcranmer 2y ago
      https://www.eia.gov/energyexplained/us-energy-facts/images/consumption-by-source-and-sector.pdf https://www.eia.gov/energyexplained/us-energy-facts/images/c... Transportation in the US consumed ~27.5 quadrillion BTUs, electricity consumption was ~13.3 quadrillion BTUs, about ½ transportation use.
  - kibwen 2y ago
    I think this is unintentionally falling into the trap that the parent commenter is railing against. Lowering consumption does not mean going from fossil cars to electric cars, it means going from cars to modes of transportation that aren't so inherently wasteful and inefficient as cars.
- nerdponx 2y ago

Peer review paper: https://www.cell.com/device/fulltext/S2666-9986(24)00235-7 https://www.cell.com/device/fulltext/S2666-9986(24)00235-7 Executive Summary: Solar heater that can work at temperatures close to 1000C by using semi-opaque materials to absorb solar energy and minimise radiative losses. Not even a proof of concept of an improved smelter. Article text in PopMech is exaggeration of paper and headline is a further exaggeration on top of that.

deleted 2y ago
[deleted]
mannykannot 2y ago
Ah - a greenhouse that can almost melt copper, though I think you need a mirror to get the "135 suns" input radiation.
scld 2y ago
The paper itself mentions the usefulness of the 1000C threshold: Solar process heat at above 1,000°C can decarbonize key industrial applications such as cement manufacturing and metallurgical extraction. The article is just running with that theme.
- jcranmer 2y ago
  > decarbonize key industrial applications such as cement manufacturing and metallurgical extraction ... so what's the reducing agent, if not carbon?
  - floatrock 2y ago
    Can you explain the chemistry pieces vs. the thermal inputs pieces?
    - jcranmer 2y ago
      The main tasks in converting iron ore to steel is as follows: reduce the iron (which requires a redox reaction), drive out existing impurities (both other metals present in the ore, such as magnesium or aluminum, and other nonmetals like sulfur or phosphorous), and introduce new ones (predominantly, uh, carbon). Note that these don't necessarily all occur at the same time, in the same furnace (steelmaking is a multistep process). These processes require the necessary chemical reagents to cause the necessary chemical reactions to occur. There are multiple roles for heat. Most notably, most of the necessary chemical reactions require high heat to occur at a time. Furthermore, outright melting gives the advantage that impurities tend to sort themselves by density, and your impurities are typically less dense than your main metal (i.e., the slag will float on top of the molten iron). There's also the advantage that high heat can make volatile impurities (e.g., sulfur dioxide) boil out. Historically, the reducing agent was largely charcoal, where you burn the wood in oxygen-poor environment to produce high purity carbon-rich material. The industrial revolution replaced charcoal with coke, where you burn coal in oxygen-poor environment to produce high purity carbon-rich material. In both cases, the furnace converts the fuel largely into carbon monoxide, which is the main actual reducing agent in contact with the iron (whereupon it forms carbon dioxide). The decarbonization assumption has been to replace carbon with hydrogen gas, but as far as I'm aware, hydrogen-based reduction furnaces have only existed in pilot plant form.
  - pfdietz 2y ago
    There's a proposed entirely-thermal iron reduction process that uses sodium as the reducing agent. This produces sodium oxide, which apparently can be decomposed back to sodium and oxygen by vigorous heating. I have my doubts about the overall feasibility of this scheme, but it doesn't involve any electrical energy input.
  - deleted 2y ago
    [deleted]

squeegee_scream 2y ago

> Fighting against climate change means building, whether that’s large solar arrays, sprawling wind farms, or powerful fission reactors Can we, maybe, consider using fewer resources? Are we past the point of imagining that we could possibly get by with a sustainable lifestyle?

jajko 2y ago
Not with electric cars slowly coming, our current infra at its max here in Switzerland ain't enough for any serious mass electrification. They dwarf all combined electricity usage by huge margin. And somebody has to generate all of it.
- smallerfish 2y ago
  You have a source on that? Sounds a lot like oil company fud. Couple of results from the top 5 when searching for this: https://www.scientificamerican.com/article/why-electric-vehicles-wont-break-the-grid/ https://www.scientificamerican.com/article/why-electric-vehi... https://www.virta.global/blog/myth-buster-electric-vehicles-will-overload-the-power-grid https://www.virta.global/blog/myth-buster-electric-vehicles-...
  - jcranmer 2y ago
    https://www.eia.gov/energyexplained/us-energy-facts/images/consumption-by-source-and-sector.pdf https://www.eia.gov/energyexplained/us-energy-facts/images/c... Transportation in the US consumed ~27.5 quadrillion BTUs, electricity consumption was ~13.3 quadrillion BTUs, about ½ transportation use.
- kibwen 2y ago
  I think this is unintentionally falling into the trap that the parent commenter is railing against. Lowering consumption does not mean going from fossil cars to electric cars, it means going from cars to modes of transportation that aren't so inherently wasteful and inefficient as cars.
nerdponx 2y ago