Ben Magelsen

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One of many applications of geopolymers, DIY by Ben Magelsen:


Conversation notes:

  • Geopolymers
  • Assemble at atomic level for porosity - zeolites
  • Can control for what molecules will fit in between material
  • Silica chemistry out of computer technology
  • 30,000 foot vie - sodium silicate water based, mix with something with higher al - metakaolin, flyash, solid. Local clays down to below a couple microns. Or from silts by leaching. Potassium hydroxide.
  • Buy sodium silicate -
  • Metakaolin - concrete supplement
  • $300/ton metakaolin. Fired to 750C, in a calciner.
  • Clay is calcined any
  • HCl leaching clay will be amorphous silicate. KOH or NaOH with it gets you sodium silicate.
  • Closed loop leaching - through ion exchange membranes.
  • NaCl - precursor to get HCL + NaCL
  • HF is nasty. HCl, Nitric, and
  • Synthetic AlN03 methydrate - pull apart a local clay and put it back in a specific manner.
  • Illite clays don't need any calcining. 5M NaOH or KOH will make good material, 3x strong portland cement. Straight to cementitious binder. 10PSI binder. 3x stronger than standard Portland cement.
  • Tell me about - geopolymer binder - added silica fume [1] + chopped carbon fiber.
  • Ductile concrete with steel fiber - 100 micron or so fiber in concrete. Lower than 100 micron thickness. Shrink the size of 'rebar' *Geologic chemistry - 100 nm - aluminum and silicate - a few ions of almost
  • Aluminum silicate - from sodium silicate with 40% solids in a suspension in water mixed with solid with another amorphous solid
  • Pumice from Idaho in large volume - taking Pumice 75 amorphous silica, dissolving in hydroxide to make the silicate. Combine that with Kaolinite.
  • Typical portland cement binder is 25% binder.
  • Only by combining certain materials with hydroxide - to get a binder.
  • Can activate flyash with hydroxide.
  • With more dilute precursor, you get a better result.
  • 2 silicate to 1 calcium is stronger. 3 calcium to 1 silica in standard portland.
  • Aluminum source - to synthetic metakaolin.
  • Silica - you can leach everything out of it, get plain silica.
  • 3D Printing paste
  • Printrbot collaboration -
  • Extruder for a printrbot -
  • Urbanforge with ASU material science - may not be open source. Simple version is open source.
  • Is into 3D printing of polymer materials. Room temperature curing versions.-
  • Portland still has water in it that spalls at high temp.
  • For paste - one is printable mold. Epoxy hydrocarbon resin for
  • Can do aluminum in standard printable refractory.
  • 2005 - American Ceramic Society - contest for the strongest ceramic coffee mug. It was geopolymer with fiber -
  • Flameware? Don't know. It's good at fireproofing. Microbeaded foam.
  • K sulicate is used for fireproofing wood and insulating steel beams.
  • Cooking pot - thermal transfer is needed. Quartz or carbon fiber. Geopolymer Composite with high quartz and make a ceramic heater. Naturally reradiates - quartz composite is good for heat elements.
  • Print a positive in a mold
  • When particles are super small, the geopolymer gets very liquid.
  • CaOH is lime - lime would slake for a year because it - time is of essence. CaCO3
  • 12-1300 is the typical cement calcining needed.
  • Solution would be - ionic liquid chemistry - electrolyze a mix na, k, carbonate. Calcine the carbon - electrodes. 750C. Carbon negative material. CaOH. Using Calcium as a tool to do
  • C02 to carbon nanotubes.
  • Silicon and aluminum are more available.
  • Induction furnace -
  • Low hanging fruit - pourable composites. Pumice is granite magma that cooled fast. Synthetic granite.
  • Geopolymer composite for 3D printed frames. Insulating materials + structure on the outside. Machine frames. Lightweight fiber composite that is fireproof.
  • Build molding package.
  • Lightweight pourable composite. Cut back on metal usage.
  • Control the ratio of alkali metals. Cesium geopolymer will have no expansion. Composite with steel that is
  • Ceramic engines -
  • Molten carbonate -
  • Burn fuel directly in molten carbonate
  • Molten carbonate ceramic engine.
  • Iron catalyzed low temp splitting of water?
  • Waste glass - calcium in glass is there to make it more soluble. HCl acid leaching. Oxalic acid leaches calcium. Google it.
  • Use waste glass to silicate to densify bricks.
  • There is only a small range of chemicals that are usable.
  • Get back to big picture - get atomic recycling.
  • Impact mills . Lucite ceramic fiber reinforced. Or AR 400.
  • Higher shear mixer -
  • Built aquaponics, aeroponics, plants, electroplating, flail mills.
  • Casting modular housing. Pour walls as a piece.
  • Molds could work.
  • Possible project for Summer of Design/Build


Hi Ben,

Could geopolymers be used as steel-casting refractory material? With the induction furnace on our plate, this would be useful.

If you mean as a material to cast steel in a mold, I am not certain. I know aluminum molds work. A typical geopolymer composite is a refractory and maintains most of its structural properties until between 800-1000c. Higher temperatures could be reached by using more advanced versions that could include materials like silicon nitride or silicon carbide aggregates in the composite. I have done some composites with silicon carbide. It forms a foam matrix that is very strong and insulating, so it may be worth looking into. If you are looking to effectively insulate a steel furnace it is a great application. The thermal expansion of a geopolymer matrix can be tailored to match the underlying metal by varying the ratios of alkali metal ions (Cs,K, Na) within the geopolymer matrix.

Another application could possibly be paints for wood - we are interested in that for our construction projects.

I have not done anything specifically with silicate paints, but have played with using a normal geopolymer binder as a coating a few times and assume it should be pretty easy and generally lies withing the same chemistry. Silicate paints have been around for over 100 years in Europe. I even understand some of the paint jobs have lasted a century. Geopolymers bind great to materials geologic materials like brick, concrete, etc.

Another interesting application would be 3D paste printing, to get high temperature ceramics, insulators, and flameware. It would be useful if there were a 3D printing route here which did not require subsequent firing.

UrbanForge is actively developing commercialization of this application with ASU's material science department. Our current thought is we will open source basic version of the binder and composite, but may leave the higher end nano composite reinforced versions proprietary for now. I do have some concern about what technologies should be released. Maybe I am just a little paranoid, but the current open technology could be used to build things that would keep the general public awake at night, if they understood and thought through the possible implications.

Another application would be cementitious material production. On our plate is simple burning of limestone with PV. See

This is the primary application we have been working on. Our approach is probably a little more technical than you may be shooting for, but is within reach. A lot of our approach is based on ionic solution chemistry, but we are also using a calcining of limestone as a chemical intermediary. We are working on calcining calcium carbonate in a mixture of molten Li/Na/K carbonates at 750c and sequestering the carbon through electrolysis as carbon nanotubes. The nanotubes will be used as fiber reinforcement in our cementious composites.

If you have not looked into what can be done with molten carbonate electrolysis, I think it may fit really well with your long term objectives. There are a lot of options with the technology not covered in the paper I attached. The leading researcher in the field, Dr. Licht of GWU, has worked on several other applications including solar driven versions.

Of special interest is CEB block in which we use our own stabilizer for SCEBs. Could we produce geopolymer with reasonable effort to make this happen? We would be interested in considering this for our next CEB microhouse build workshop in Belize -

Geopolymers can be used for a CEB, but self consolidating versions would not really need the compression. Reaching fired brick type strengths is very easy and composites with 10x strength of OPC are attainable with majority of strength reached in first 24 hours. You may not want to go the route of a full geopolymer, but you certainly could use the chemistry as an additive to enhance the strength of your CEB.

Are these 5 applications doable using a simple geopolymer route, which we could test in experiments? We are doing 1 month of construction immersion next summer, and I'd be interested in considering geopolymers in the curriculum so we can run some practical experiments. Can you propose any geopolymer product that we can produce that has the potential to produce a near term cash flow?

All of the applications are doable. A starting place may be to see what local precursors and industrial waste products may be available in your area. As for geopolymer products for cashflow, that is something we could discuss. UrbanForge is pursuing some commercialization of the materials themselves to fund our objectives. From a practical standpoint, there are all kinds of commercial products that could be built better with geopolymers. I would think things as simple as a rocket stove, kilns, forges, BBQ, etc, could be manufactured as a profit center.

As a side note, geopolymers can also form an artificial granite composite similar to those used in the most advanced high precision CNC machinery. The advantage being the vibration dampening is several times greater than cast iron. UrbanForge has started developing an advanced multi purpose manufacturing cell using the technology. I though that may be an application that may be of interest to you.

As a final note, these applications are only scratching the surface of what may be possible. Geopolymers are really a subset of sol gel and zeolite chemistry. That means molecular sieves, water purification, and many other applications are possible within the broader applications of the technology.