[Stoves] Fly ash cement, Curiosity, contibnued---

Mon Feb 9 05:20:44 CST 2015

Hi Dean,

Whilst being without the facilities to test the material continuously
I can say it has only very limited erosion by flame. Direct contact
with flame is no problem and the material acts very much like a
ceramic. In the stoves it does expand and contract a little but is
very tolerant of cracking and the cracks do not lead to breakage in
the same way as a fired ceramic. It certainly does not crumble in the
way a portland cement stove would. Pieces of KSIAL geopolymer have sat
inside a firebrick lined woodstove and lasted a fully heating season.
The pieces are brittle but not eroded.

Our prototype cook stoves have seen a fair bit of use and are holding
up well. The grate of the larger charcoal stove is still functioning
well and has been repeatedly been loaded with charcoal (and wood) and
burnt down to ash. I have noticed some minor cracking in the stoves
but nothing that goes through or causes breakage so far.

Repairability is proven and can extend the life of a stove
considerably. In the attached photo of the rocket stove the turbulence
inducing bumps in the chimney were added after the stove was made and
used. New material bonds to old and can be used to repair cracks and
broken pieces in a simple workshop.

As different densities can be made in the one casting a hard liner can
be backed up with a low density more insulative version of the same
material. There is also the possibility of using KSIAL as a 5 -10 mm
thick cast-in liner to other materials such as cobb. It certainly has
some possibilities to be explored.

Best Regards
Thomas Hastings
Unity Stove

On Mon, Feb 9, 2015 at 11:48 AM, Dean Still <deankstill at gmail.com> wrote:
> Hi Tom,
>
> How long does your material last at 850 C contacted by flame?
>
> Best,
>
> Dean
>
>
> On Sun, Feb 8, 2015 at 2:35 PM, <mtrevor at mail.mh> wrote:
>>
>> Glad I re-opened the topic and that Tom has been brought in to it.
>> It is exciting to here that Ron Christa an other have also picked up
>> geopolymers
>> You all being where access to materials are available with multiple
>> people could lead to something great.
>>
>> Watch and waiting to see the developments by all.
>>
>> Michael
>>
>> -----Original Message----- From: T Hastings
>> Sent: Sunday, February 08, 2015 10:19 PM
>> 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.
>>
>> On Sun, Feb 8, 2015 at 5:54 PM,  <mtrevor at mail.mh> wrote:
>>>
>>>
>>>
>>> From: Crispin Pemberton-Pigott
>>> Sent: Sunday, February 08, 2015 3:57 PM
>>> To: 'Discussion of biomass cooking stoves'
>>> Subject: Re: [Stoves] Fly ash cement, Curiosity.
>>>
>>>
>>> Thanks.
>>>
>>>
>>>
>>> Did he say if it is transportable? Or does it have a very short packaged
>>> life?
>>>
>>>
>>>
>>> All you need is to find one of those mixing plants.
>>>
>>> Crispin
>>>
>>>
>>>
>>> If anyone is interested ----I made an inquiry with Zeobond. The E-crete
>>> is
>>> not available in powdered bagged form.
>>>
>>> It is a commercial large mix batch plant product.
>>>
>>>
>>>
>>> Michael
>>>
>>> Marshall Islands
>>>
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