[Stoves] Fly ash cement, Curiosity.

[Crispin Pemberton-Pigott]

Thomas, what a great and brief reintroduction.

Thanks for the name and reference.

This is a good link:

http://www.philipcoppens.com/davidovits.html

Perhaps we should be looking for a different solution entirely.

Crispin


-----Original Message-----
From: Stoves [mailto:stoves-bounces at lists.bioenergylists.org] On Behalf Of T
Hastings
Sent: Sunday, February 08, 2015 17:19
To: Discussion of biomass cooking stoves
Subject: Re: [Stoves] Fly ash cement, Curiosity.

Hi Michael, Crispin and all the list members,

Rather than answering or responding to all the questions and notes raised on
this topic I will try and share with you some of my experience on Fly ash
for stoves.

What I believe Michael has read about and discussed with Zeobond is Fly ash
based geopolymer. These are cement like materials made by mixing Coal fired
power station waste (fly ash) with an alkali activator. The theory is that
the alkali dissolves at least a portion of the fly ash which is mostly
aluminium and silicon. These ions recombine to former a polymer or chain
like structure utilising the alkali cation to balance the charge of the
aluminium atom.

Several companies are developing it as a low CO2 replacement for OPC
(Ordinary Portland Cement) They mix the binder with regular aggregates to
make a OPC substitute.

In Australia, Zeobond have used a fly ash material to make footpaths and
some precast past. The mixing plant they refer to is a cement batching
plant...its big.
Another company in Queensland, Wagners have made very large precast beams
for a government building and are or will be making a airport runway from
their Earth Friendly Concrete.

You can look Wagners up here http://www.wagner.com.au/capabilities/efc/

In South Africa, geopolymer is also making inroads For example  0% cement
concrete - M&R geopolymer concrete a South African first!!
https://www.youtube.com/watch?v=wArEbfC91m0

My own work at Unity Stove is similar but different. For these companies to
be successful they have to produce a product that is comparable in price and
performance to bulk portland cement type concrete for building works. I am
really not how sure their materials will work in furnace lining type
applications like the inside of solid fuel stoves.  The KSIAL material
developed by Unity Stove is more expensive to manufacture as it uses a far
greater portion of activator to try and achieve more dissolution of the
aluminium and silica sources. We also use different aluminium and silica
sources ( due in part to fly ash coming in tanker truck loads only) Also to
avoid legal issues KSIAL is based on old patents....yes geopolymers having
been around long enough for patents to expire. Like their materials, KSIAL
it not a DIY just add water product like portland cement so it very hard to
bag some up and hope that an experimenter follows the instructions to mix
and cure correctly.

I am sure it a type of stove material that some of the well funded
organisations working in this field will pick up and run with one day.
As I have been promoting, geopolymer materials such as KSIAL will allow
corrosion resistant stoves to be produced in small workshops using readily
available materials. Stoves can be repaired and or crushed and recycled to
make new stoves. It is compatible with insulating aggregates such as
perlite, scoria and wood ash and can even be foamed to make a stove liner,
pot support and insulation in one piece. Its low thermal conductivity means
the surface may get hot but will not instantly burn skin in the way a metal
stove can.

Anyway Michael, you are definitely on the right track with Fly Ash cements
and I would just love to pop over to the Marshall Islands with a 20'
container of materials and everything needed to start a mini factory and
start making stoves with you.

Regards
Thomas Hastings
Unity Stove





Some keywords for further research if you are interested in researching this
type of material further. Be aware though that Prof.
Davidovits does believe the pyramids are constructed from Geoploymer and has
even reconstructed and demonstated how they could have been built using Nile
silt and Natron.

Davidovits Geopolymer alkali activated cement refractory foam and of course
google Unity Stove to see Geopolymer stoves in use.