Straight away LTGS Binder based on Reactive Minerals

[Deleted]

With reactive minerals like zeolite, fly ash or metakaolin the usual 1/1 ratio of mineral to lyel of a LTGS binder
can be increased to a 2/1 to 3/1 ratio for KOH and to a 2/1 to 4/1 ratio for NaOH.
With additional external heat higher ratios may be possible.

As usual mix dry mineral and dry lye and add small amounts of water and stirr.
Add just enough water to dissolve the lye completely and get it smooth, the result should be a paste, not a liquid.

Clinoptilolite one of the more common natural zeolites is very reactive due to it's molecule, which is shaped like a honey-comb.
A relatively cheap source of Clinoptilolite zeolite iin the USA is the Sweet PDZ stall freshener, which is available granular and as powder.
Sodium hydroxide is strong enough to dissolve granules of 0.5mm-1.0mm with a 3/1 ratio.
Potassium hydroxide cannot dissolve granules at least not without external heat.
In general zeolit granules are better suited as aggregate. than as mineral source for a binder.
If Clinoptilolite is also used as aggregate the binder must contain 7% NaOH or 10% KOH of the total dry mass to get a strong result.

A zeolite based LTGS binder can be used as an universal binder and as a much cheaper waterglass replacement.
However due to the alumina content it is not storable like waterglass, because it will harden over time.

20% zeolite based binder, which equals 5% lye, allows castable clay geopolymer mixtures.
With 20% binder of a 1/3 ratio a sack of 25 lb Sweet PDZ  plus about 8.3 lb of lye would be enough for about 167 lb of geopolymer refractory.
With 20% binder of a 1/4 ratio a sack of 25 lb Sweet PDZ plus about 6.3 lb of lye would be enough for about 157 lb of geopolymer refractory.
One can use three of four sheets of toilet paper per kilo dry mixture to prevent drying cracks.
Chopped rock wool fibers of about 4-10mm could be used too.
Using reactive lime or cement as accelerator is possible, but will make the result much more brittle.

Quick lime as accerlerator allows to take advantage of chemical heat for fast setting.
10% quick lime and about 5% short mineral fibers allow to create aerogel clay geopolymers with extreme insulating properties.
Ball clays are especially suited for aerogel clay geopolymers, but may require 30% - 40% binder, equaling 7.5% - 10% lye.

Aluminates made by dissolving aluminium in lye will act as accelerators as well.


See also:
Simple and Straight away LTGS Binder.
donkey32.proboards.com/thread/2372/simple-straight-away-ltgs-binder

Zeolite 0 - 1 mm 25 kg, which is fine enough to be dissolved in a 3/1 ratio with NaOH for a binder and also a good aggragate.
Even a 4/1 ratio is possible if one works fast and careful.

For about 8€-10€ without shipping
Netherlands
www.ebay.nl/itm/Zeolith-25-kg-Filtermaterial-Phosphatbinder-Zeolite-Zeolit-Koi-Garten-Teich/120956892701?hash=item1c2997b61d:m:mj2Fgj-8wSJ2jondf1zSu3Q
France
www.ebay.fr/itm/ZEOLITH-0-1-MM-25-KG-ZEOLITE-SAND-KLINOPTILOLITH/121152119381?hash=item1c353aa255:g:TF0AAOSwFNZWu142
Italy
www.ebay.it/itm/Zeolith-25-kg-Filtermaterial-Phosphatbinder-Zeolite-Zeolit-Koi-Garten-Teich/120956892701?hash=item1c2997b61d:m:mj2Fgj-8wSJ2jondf1zSu3Q
Spain
www.ebay.es/sch/i.html?_odkw=Zeolita+0+-+1+mm+25+kg&_osacat=0&_from=R40&_trksid=p2045573.m570.l1313.TR0.TRC0.H0.XZeolit+0+-+1+mm+25+kg.TRS0&_nkw=Zeolit+0+-+1+mm+25+kg&_sacat=0
United Kingdom
www.ebay.co.uk/itm/ZEOLITH-0-1-MM-25-KG-ZEOLITE-SAND-KLINOPTILOLITH/121152119381?hash=item1c353aa255:g:TF0AAOSwFNZWu142

[Deleted]

I have performed a few fire tests on about 4 cm thick zeolite based LTGS samples.
The Kemper Tornado blowtorch for butane gas has a power of about 1.3 KWh,
throwed on a quite small area, with a flame temperature of 1800°C/3272°F.
Nothing even remotely similar will ever occur anywhere in a rocket stove.

After ten minutes yellow orange glowing on one side
the temperature on the reverse side had only raised by about 60°C,
which indicates a very good insulation value.
From former tests I know a longer period of time would not have changed much.

No signs of melting or deterioration were recognitiable, only the color had changed.

[pigbuttons]

Thanks Karl, for continuing to expand our knowledge base of all things 'geopolymer'.
Question one: If I already have a Potassium hydroxide based geopolymer and just want it to cure at a lower temp, can I just add some Sweet PDZ ( assuming I experiment to get the proper ratio )?
Question two: Will adding the Sweet PDZ reduce the max temperature performance of the product?
Question three: Are the ratios above by weight or by mole?

Thanks again.

[Deleted]

NaOH is only required to dissolve granular zeolithe.
KOH can do that only with an external heat source.
Fine zeolite powder works with KOH as well.

For significantly lowering the curing temperature the mixture would require about 50% zeolite.
As describe above I have tested it with a butane torch with a flame temperature of 1800°C/3272°F.
I do not have welder torch to test it against even higher temperatures.

The ratios are by weight.
The different recommendations for NaOH and KOH do reflect the difference in molar mass.
56/40 ~ 10/7


General advertisement for super cheap geopolymers:
With a zeolite based binder one can even use loess loam to make refractory.
By weight, the mineral composition of loam is about 40–40–20% concentration of sand-silt-clay.
en.wikipedia.org/wiki/Loam

I recommend to coat a "lost form" with such extremely poor clay soils
and not to try to make a regular casting.

Layered coating especially if reinforced with fibers of any kind is an extremely powerful building technique,
much more powerful than casting.

[esbjornaneer]

What is the difference between fly ash and wood ash? I should ask google.
How much Zeolite is needed to make a 15cm BBR or DSR core of 4cm thickness? Would one add local soil to the mix?
How would one proceede once the paste consistency has been achieved?

Great lot of information here but as a total beginner on geopolymers it is a bit boggling. A Dummy's guide is what I would love

[Deleted]

Dec 21, 2017 9:53:39 GMT -8 esbjornaneer said:

What is the difference between fly ash and wood ash? I should ask google.

Fly ash is the spherical ash createt by burning powderized fuel which is blowed into the fire.
The mineral composition depends on the fuel,which may be coal or wood.

How much Zeolite is needed to make a 15cm BBR or DSR core of 4cm thickness?

A sample made from 0-1mm zeolite got a dry density of 1,2 Kg per liter,
which means that more than 50% of the volume is air.
Natural zeolites have close to 40% porosity, thus not much is needed to drive it over 50%.

Zeolites are relatively soft with a hardnes of about 4.5, thus a mixture with granular zeolite as aggregate will stay relatively soft as well.
Powders will get denser and much harder.
On average about 1.5 Kg per liter.
Can be adjusted with water.
Mixtures with dense aggregatees like basalt powder or fine grog can get close  to 2.0 Kg per liter.

Would one add local soil to the mix?

Can be done, yes.

How would one proceede once the paste consistency has been achieved?

Do you mean the binder ?
Add it to the aggregate and mix it with water to the desired consistency.

[wiscojames]

Remind me what you used for aggregate, please.

[pigbuttons]

One more question Karl, can you give us an estimate on how much the zeolites shrink during the curing process? Say compared to kaolin, which for me is about 0.2%, mostly in the early hardening ( drying? ) phase.

[Deleted]

Dec 21, 2017 19:45:19 GMT -8 wiscojames said:

Remind me what you used for aggregate, please.

I have made experiments with zeolite, fly ash, metakaolin, different clays from kaolin to loess loam,
different micronized stones like basalt, diabase and different feldspars, different grogs dense and porous, hollow microballs made of bor-silicate-glass,
organic and inorganic fibers and many more.

Micronized basalt is a great aggregate and easily and cheap available here.
Basalt is famous for low thermal expansion and high hardness.
Casting clays, which are mixtures of clays and feldspars make great aggregates as well.

I strictly advice against the use of expanded perlite or vermiculite, which give poor and brittle results.

[Deleted]

Dec 21, 2017 22:12:54 GMT -8 pigbuttons said:

One more question Karl, can you give us an estimate on how much the zeolites shrink during the curing process? Say compared to kaolin, which for me is about 0.2%, mostly in the early hardening ( drying? ) phase.

Zeolite has a low shrinkage.
Pure zeolite should be reinforced with short mineral fiber.
All mixtures with high amounts of water should be reinforced to prevent drying cracks and reduce shrinkage as well.

[wiscojames]

Karl, sorry if I missed this, but have you used your local clay rich soil as an aggregate?

[esbjornaneer]

Hello Karl,
I looked into the link for Zeolith for Spain and found that it would cost me almost 40euros/bag and your weight info above couples with 48litres for a 40mm thick DSR wall or 30litres for a 25mm wall DSR would mean that I wanted 3 bags (using only Zeolith). So all of a sudden it did not look like it would be much cheaper than ceramic board...

So instead I did some research on the local clay that is used on roofs here, called 'launa'. I had ben told in the past that it is an aluminium clay, but wikipedia say it is magnesium based (https://es.wikipedia.org/wiki/Launa). It is a very expansive clay which is why it is used as a water proofer here. Then I looked up what wikipedia had to say about expansive clays (https://en.wikipedia.org/wiki/Expansive_clay). Am I right that this article is talking about the SiO/AlO=2 that is mentioned in the PDF above?

Anyway, I thought it was worth giving it a go. So I mixed equal weights of launa and caustic soda. I am not sure I added enough water as there were still some small soda crystals in the mix when I tought it was getting too wet. I have poured it in a plastic container to a depth of about 20mm to see how it behaves.

What I am looking for is a highly insulative mix so I did not bother to shake the container( = vibration table) to let the air bubbles out of the mix. Almost all Youtube videos I found were vibrating the stuff they had poured. Should I have? What else should I do to get a lighter slab at the end? I did not add any fibers as this first test is to see if it comes hard-ish at all. Should I try less soda in other blocks too to see if I can get away with less or is that a waste of time?

Thanks for any feedback and advice to proceede, Esbjorn

[Deleted]

Our local soil is an up to 5m thick layer of loess loam formed by the accumulation of wind-blown dust.
Likely it has not more than 20% clay maybe even less.
With zeolite based binder and cured above 100°C/212°F loess loam becomes sufficiently water resistant.
It passes the water test suggested by Davidovitz.
Submerged for 24 hours it holds it's form and even thin pieces keep sharp edges.
Pieces regain about the former strength if dryed.
It has a very good insulating properties.

I think its about the worst sample of clayed soil.
This kind of soil is very common in the rather southern parts of Europe.

[Lucian]

Karl,

I have lots of waste red brick dust resulted from wet saw cutting of full bricks into slips.
The dust is extremely fine.
Do you think it would make a good aggregate to be mixed with a zeolitic binder?

Or could it even be mixed with NaOH to make a binder? (I read somewhere the brick dust is reactive...) If so, what proportions?

I'm sorry if these are silly questions, I'm a complete novice in geopolymer technology
Thanks for sharing your knowledge!

[Deleted]

Dec 23, 2017 7:28:20 GMT -8 esbjornaneer said:

Then I looked up what wikipedia had to say about expansive clays (https://en.wikipedia.org/wiki/Expansive_clay).

Clays of the Smectite Group contain only small amounts of magnesia but between 10%-30% alumina.
Montmorillonite contains about 18.5% alumina.
It is the most common component of swelling clays.
Swelling clays may require a few percent of reinforcement with mineral fibers to keep shrinkske low and prevent cracks.

So I mixed equal weights of launa and caustic soda.

That is the standard LTGS recipe for a binder.
The extreme amount of lye keeps a binder water soluble even if it got hard.

What I am looking for is a highly insulative mix

Geopolymers with swelling clays can achive extremely high insulating values.

Even if the zeolite is relatively expensive for you it can bind many time it's own mass of cheap or even free material.