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Post by Deleted on Sept 4, 2014 10:11:43 GMT -8
I love science, the one for pragmatic and in practice viable solutions, not those for record-obsessed nerds. Oh well, sometimes I am a nerd too. I have made some more experiments, even with homemade waterglass. After lots of experiments I have to say: My prefered material is grog, all kinds of grog, from cheap stoneware grog to molochite. That is not just because in Germany it is virtually impossible for private persons to get metakaolin. Grog is just not so fussy. Prepared partially dissolved grog beats waterglass in many respects. Metastar with partially dissolved molochite hardens faster and stronger, than with homemade waterglass containing the same amount of solids. Commercially available waterglass contains less solids. Baking powder is great to blow slurries up a bit, and even harden it. Do not know why, will have to look up. I remembered, baking powder hardens the geopolymer through the acid fraction, acting as an accelerator. One experiment of molochite filled with 0.5-1mm natural zeolithe got pretty hard, fast.
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Post by Deleted on Sept 5, 2014 4:09:24 GMT -8
argical m1000 is both a lot cheaper,about 1/2 the price of metastar 501, and a lot easier to find. i got mine from chalkdown lime in the UK, but anyone doing lime rendering and renovation work should carry it. Lucky UK members. At such shops one can also get cheap fly ash, ground granulated blast furnace slag. lime, chopped hemp and lots more that may be of interest. Chopped hemp can be used as an aggregate supporting the escape of water, and lowering weight. Short fibers do not clump as easily.
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Post by Deleted on Sept 5, 2014 4:29:11 GMT -8
Ingredients of baking powder:
1.) Sodium bicarbonate 30%
2.)Diphosphate 20-30%, usualy disodium pyrophosphate as a weak acid, which is very reactive due to polyvalence. For geopolymers sodium aluminium sulfate would be advantageous. As a stronger acid some citric acid could be added.
3.)Starch.
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Post by ronyon on Sept 5, 2014 5:23:44 GMT -8
I have a hard time following this thread, but it seems well worth the effort, so I will slog on. As for added fibers, would stone wool insulation be of use?
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Post by Daryl on Sept 5, 2014 5:33:18 GMT -8
I love science, the one for pragmatic and in practice viable solutions, not those for record-obsessed nerds. Oh well, sometimes I am a nerd too. * thumbs up * You provide a wealth of information. Keep it up. Cheers!
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Post by Deleted on Sept 5, 2014 7:57:07 GMT -8
Stone wool insulation is not needed for geopolymers, IMHO.
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Post by smarty on Sept 5, 2014 8:29:38 GMT -8
So is the argical calcined at 750 degrees or does it not seem to matter. Hoping to get back to this stuff now that I'm back home again.
What would be the chances of making a geopolymer based on chalk - this is the only stuff I have on site. I guess it isn't ideal stuff to make thermal mass out of, though it might do for the casing of the main bell if you wanted to buffer the transfer of heat a bit (if the place is a new build and insulated up to current regs. I'm thinking some of my home made MK-750, some lye, some cheap lime based sand or granules and chalk aggregate mixed up and rammed into moulds to make some kind of bricks or panels.
I got the kiln fixed and baked some Kaolin at 750 for an hour so I'm hoping to try mixing up a few batches of geopolymer to see how much difference it makes compared to the raw kaolin. If the argical is cheap then i'll go for that to save the messing around.
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Post by smarty on Sept 5, 2014 8:42:39 GMT -8
just took a look at chalk down lime website and chalk is listed as a pozzolan, is that right? I've been googling chalk geopolymer and drawn a blank, so if this is right its good news because chalk is one thing I have tons of. Thanks for the link Photoman even though it took me a while to realise what a great resource they are, and so near where I am!
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Post by Deleted on Sept 5, 2014 9:55:25 GMT -8
So is the argical calcined at 750 degrees or does it not seem to matter. It does not matter, even molochite kalcined at 1525°C is still reactive enough. It is not possible to use chalk directly for high temperature refractory. At about 800 °C chalk will be reduced to quicklime and carbon dioxide. You could do this in your kiln. Quicklime can be used to create calcium silicates/aluminosilicates, which have melting points above 1400°C. However, chalk could be used as an aggregate for parts, which will never go above 600°C just took a look at chalk down lime website and chalk is listed as a pozzolan, is that right? The heading is pozzolans and additives. Chalk is not a pozzolan, but burnt chalk is part of the pozzolanic reaction.
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Post by photoman290 on Sept 5, 2014 15:31:33 GMT -8
i have found a source of zeolite £24 for 25kg 07-1.6mm plus carriage. £12 using parcel force 48. i got them to collect it. RS minerals middlesbrough. i spoke to rob sampson who arranged it all for me.
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Post by Deleted on Sept 6, 2014 2:29:39 GMT -8
i have found a source of zeolite £24 for 25kg 07-1.6mm plus carriage. £12 using parcel force 48. £36 ~ 45€ including shipping, that is expensive. Did you have looked at shops for aquariums and ponds? In Germany one can get 75kg natural zeolite including shipping for this price. Cat litter from natural or synthetical zeolite is not very expensive too. One could even order at alibaba.com, let it ship from asia and save some money.
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Post by smarty on Sept 6, 2014 5:33:46 GMT -8
What is the idea behind the zeolite? I looked it up on wiki and it said this:
"Biogas Industry The German group Fraunhofer e.V. announced that they had developed a zeolite substance for use in the biogas industry for long-term storage of energy at a density 4x more than water. Ultimately, the goal is to be able to store heat both in industrial installations and in small combined heat and power plants such as those used in larger residential buildings.
Commercial and domestic Heating and refrigeration Zeolites can be used as solar thermal collectors and for adsorption refrigeration. In these applications, their high heat of adsorption and ability to hydrate and dehydrate while maintaining structural stability is exploited. This hygroscopic property coupled with an inherent exothermic (energy releasing) reaction when transitioning from a dehydrated to a hydrated form make natural zeolites useful in harvesting waste heat and solar heat energy. Zeolites are also used as a molecular sieve in cryosorption style vacuum pumps."
So is that what the zeolite is for? Some kind of thermal storage?
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Post by Deleted on Sept 6, 2014 5:51:57 GMT -8
Zeolithes have an extremely large inner surface, due to a cellular structure. The cellular structure causes a relatively low weight and low thermal conductivity. Also, the chemical composition of zeolites is similar to that of geopolymers.
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Post by Deleted on Sept 6, 2014 6:31:04 GMT -8
smarty, would you be interested to get some of my samples, fire them in your kiln when completely dry and report about them ?
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Post by photoman290 on Sept 6, 2014 9:17:07 GMT -8
i think the zeolites will absorb any water released after the geopoplymer is heated as well. from what i understand from the last paper i referenced,but as karl has pointed out that paper should be viewed with a sceptical eye.
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