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Post by smarty on Jun 6, 2018 23:42:42 GMT -8
Thanks to my interest in geopolymers having been sparked by members of this forum, I’m off to Davidovit’s geopolymer course and conference in July. So if anyone has any questions or geopolymer ideas they want me to ask then let’s make a list and I’ll see if I can get a few answers. The course promises that I’ll come away with one concrete recipe and one ceramic recipe with a list of suppliers for materials. I’m hoping to also wangle a recipe for high-temperature concrete out of them as well. The course is a bit pricey, but the conference is only about 50 euros so if there’s anyone living in France who fancies going then two heads would be better than one as they say.
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Post by Deleted on Jun 7, 2018 6:54:03 GMT -8
IMHO for average people attending the course or conference is a waste of time and money.
The recipes of Davidovits are virtually useless without exactly the same materials.
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Post by Deleted on Jun 7, 2018 8:59:03 GMT -8
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Post by sksshel on Jun 8, 2018 4:58:03 GMT -8
I suggest you try to come away with a recipe that meets these requirements:
(1) well documented
(2) simple
(3) cheap
(4) made from widely available components
(5) consistent components (portland cement is pretty consistent, etc)
(6) Tested - able to withstand the tests of time in an RMH/BBR/DSR/etc
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Post by sksshel on Jun 13, 2018 9:30:19 GMT -8
smarty I'd like to see someone pursue testing some of @karl 's suggestions in this thread: hereI'm well down the road with the Kansas City #1 recipe. I have my hands full with it. Keep us posted on whichever path you chose.
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Post by smarty on Jul 9, 2018 8:59:06 GMT -8
Here are the public domain recipes that we did today. app.box.com/s/s01hl61x2xo7h0z2oak73hnw2z9zjsqgI don’t think that any are core high temperature - I still need to check what temperature they are good for but they should be fine for tiling or forming panels around the stoves. French people are lucky in that the suppliers are mostly French i think. |
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Post by Deleted on Jul 9, 2018 9:38:58 GMT -8
The only problematic component is the SiO2 sand, which is a reconstructive polymorph.
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Post by smarty on Jul 10, 2018 10:48:28 GMT -8
The only problematic component is the SiO2 sand, which is a reconstructive polymorph. It’s from a company called silmer in France the reason they like to use it is that it reacts on the surface. The main thing is the paste that needs mixing for 10 min before adding anything else. I’ll write up more with a video when I get back. The silicate they recommend has all the alumina species in optimum ratio and is specially formulated as a geopolymer hardener. You can start with the paste and just add whatever else you want. Although only by adding the slag at the end do you get room temp setting. Today there was a session on phosphate based geopolymer for high temp uses. I’ll post what I understood of this later. But you are probably ahead of the game. I have the recipe and curing method so I’ll stick that up later. |
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Post by branja on Jul 11, 2018 2:14:52 GMT -8
MK-750 is actually sold by "geopolymer institute" for a past couple of decades. In my op, it is just comercialysation. No wonder the suppliers are French
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Post by smarty on Jul 11, 2018 4:58:53 GMT -8
MK-750 is actually sold by "geopolymer institute" for a past couple of decades. In my op, it is just comercialysation. No wonder the suppliers are French MK-750 is made by Imerys? As well as various other manufacturers. The reason is that it is the best temperature for reactivity. |
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Post by smarty on Jul 11, 2018 8:48:19 GMT -8
The only problematic component is the SiO2 sand, which is a reconstructive polymorph. The sand or range of aggregates are all made from this stuff. en.wikipedia.org/wiki/CristobaliteThey can be swapped for other minerals depending on local sources. If substituting the metakaolin in the binder for other active minerals the optimum has always proved to be 10% or less. |
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Post by smarty on Jul 11, 2018 8:52:02 GMT -8
More on MK-750.
MK-750 has different reactivity based not just on geological source but also calcifying process, as well as the milling process.
High reactivity affects the rheology of the mix. High reactivity can make it much stiffer and harder to mix in aggregates. So selection of reactivity depends on what you are doing with the mix.
Reactivity increases with the expansion of the particle platelets that are stacked like sliced bread. This opening up exposes more surface area to react. It also increases with the reduction of particle size which also increases surface area.
Argical M-1000 made in France, MK40 made in Ukraine are made using a rotary kiln. They are not so reactive.
Metastar is made in the USA. It is produced using the Herreshoff kiln. They are most reactive. Pozzolanic index of 1400.
Argical M-1200S is made using a flash kiln in France. It has a pozzolanic index of 1370 and a less open structure.
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Post by smarty on Jul 11, 2018 8:54:10 GMT -8
Phosphate Geopolymer.
50g MK-750
50g H3PO4 Phosphoric acid (85% concentration)
20g Water
Heat cured.
The resulting Geopolymer has 0 porosity. Unlike alkali geopolymer which has microporosity for vapour to escape acid geopolymer has no where for vapour to go.
At 80C peak exotherm is 108C the escaping vapour distorts the shape.
At 60C exotherm is 106C And occurs later but still vapour problems.
Optimum temperature for curing has been found to be 55C for 24 hours.
2/3rd of curing is the thermoplastic hardening.
1/3 of this is the actual hardening.
Can try monoaluminum phosphate + MK-750.
Or combination of monoaluminum phosphates and silicates + MK-750.
Silicate based only resistant but not serviceable at1400C. Phosphate more specialist for heat resistance.
‘Thermabond’ by Stellar Materials make Phosphate based refractories. They are US based.
Expanded corundum chammotte as insulating aggregate?
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Post by Deleted on Jul 11, 2018 9:33:34 GMT -8
Cristobalite is a high-temperature polymorph of silica.
If it gets hot enough and cools slowly it may become tridymite and quartz.
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Post by Deleted on Jul 11, 2018 9:42:13 GMT -8
Phosphate Geopolymer. 50g MK-750 50g H3PO4 Phosphoric acid (85% concentration) 20g Water Heat cured.
Add small amounts of organic acids and you can use natural kaolin instead of MK-750.
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