low cost, long lasting combustion chamber

I am working with the non-profit Return2Haiti. We have been requested by the community of Belle Anse, Haiti to work with them in developing the local manufacturing and distribution of rocket stoves. Rocket stoves are seen, in the community, as a practical  alternative to charcoal cooking and as a stimulus for reforestation. Belle Anse is an isolated, rocky, deforested region of Haiti without clay or sand deposits.
Currently we are working to develop a single pot cooker prototype. We are working to develop an affordable, house-hold stove that is a combination of materials available on island and low cost building materials we import. The big challenge in this is coming up with a low cost, long lasting combustion chamber. As wood ash is radially available and costless, and an easily manufactured box made of cement board, j-channel and dry-wall corners is proving effective the combustion chamber does not have to be insulting.  
We have experimented with various configurations of fire-brick and/or chimney tile with less than stellar results.
One alternative we are looking at is mold-able refractory cement. This is a materiel, and entails processes we have no experience with and may prove to be coast prohibitive. Baldosa tiles seam a viable material. Baldosa tile is a tile manufactured in Central America. It is low cost and has successfully lasted years in field trials as a rocket stove combustion chamber. Sourcing baldosa tiles is proving difficult. I am looking initially for a small supply to prototype and initiate field trials in Bell Ance.
Any thought, ideas and suggestions would be greatly appreciated.
Thank-you,
Jack Slaggert

Since it looks like you have clays in Haiti even if not very local you.still have the start of a refractory mix, Is a kiln to thoroughly fire cast pieces doable? This is assuming you want to manufacture in one place and move to be used elsewhere not built in place. Importing clay from within Haiti has got to be significantly cheaper than importing fired materials.

Steel holds up fairly well to high heat  Can you adapt some common source of scrap steel (such as tire rims) to your combustion chamber?

baldosa is the spanish word for tile, perhaps it is a company, but it may just be a generic label on the product.


could the rocks be used like a brick? what happens if you take whatever you can get from the ground and put it in a bunch of water for a week or two? i've been to haiti, but not your region. can you get a shovel in the ground at all to do a soil test for a sand/silt/clay ratio?

Something similar to what your doing perhaps:
Insulative Clay Combustion Chambers

Donkey at Proboards has made his own natural refractory stoves
Proboards

Jack Slaggert wrote: As wood ash is radially available and costless

You might want to try experimenting with the locally available wood ash, wetting it and forming can form a geopolymer that will harden to a ceramic with relatively low heat  You could make insinuative material by foaming or adding sawdust that will burn out and leave voids.

Keep in mind that you either want to make out of brick shapes or casting multiple pieces otherwise a monolithic casting will likely crack in places where you don't want it to, due to wide temperature differences and expansion rates through the rocket core.

Here is a video from the awesome Primitive Technology youtube channel where he makes a pot from woodash.