The chemist ranks the powder. The engineer buys the cube.
Every absorbent material is ranked as a loose powder and bought as a pressed solid. Pressing costs surface area, it costs different materials different amounts, and that is enough to reverse the ranking on the way into a plant.
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The sugar cube
Loose sugar dissolves in coffee instantly. Press the same sugar into a cube and it sits at the bottom of the mug. Same molecule, same mass, far less surface for the liquid to reach. Every absorbent material goes through the same thing before it enters a plant.
Why powders get pressed
You cannot pour a powder into a tower: it blows out the top or packs into a brick that nothing flows through. So real absorbers run on pellets, beads and extrudates, powder pressed with a binder. Nuclear fuel does the same thing for the same reason: UO2 powder is pressed and sintered into cylinders roughly 8 mm across, then stacked inside a zirconium alloy tube.
What pressing costs
Robust metal-organic frameworks lose roughly 10 to 15 percent of their surface area at typical pelletising pressures of 100 to 150 MPa; fragile ones lose up to 43 percent. One common binder cost a framework 40 percent of its surface area through pore blockage, and another cost 32 percent of its CO2 capacity.
Why the ranking flips
A material ranked first as a powder can lose to the one ranked fifth once both are shaped. If the leader gives up 40 percent and the fifth-place material gives up 10, the order you published is not the order that reaches the tower. Rank the shaped form, per dollar, per tonne captured.
Sources
Understanding porosity loss in MOF pelletization. ACS Omega, 2025: the 10 to 15% figure for robust Zr frameworks at 100 to 150 MPa, and up to 43% for MIL‑53.
The impact of binders on framework composite pellets for CO2 capture. Chemical Engineering Journal, 2025: 40% of surface area lost to a silicone resin binder on UiO‑66; 32% of CO2 capacity lost to PVA.
From MOF powders to shaped solids. Review, 2023: background on shaping routes: pellets, beads, extrudates, monoliths.
Technologies for manufacturing UO2 sintered pellets. OSTI: the fuel pellet: powder pressed and sintered, then loaded into zirconium tubes.
EP0395979A1, method of making a UO2 fuel pellet. Patent: the pressing and sintering steps in detail.
Reflux is being built to carry these constraints into the process model
So that the thing you have to buy, the shaped and pressed form, is the thing the model is actually about. Reflux drives the simulation software you already use from plain English.
We’re opening a small trial to people who ask for it, and we are not precious about which software you run. Whatever you use, we’ll build for it.
Nathan Ruberto · Co‑Founder, CEO
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