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Dan Nasirpour

Dan Nasirpour

Kiln Geezer - an Intermediate Technology Kiln


An intermediate technology solution, a kiln design for firing ceramics and pottery in a more sustainable way.


Making pottery consumes large amounts of fuel and many countries have ceramics industries.  Few are technologically advanced enough to manufacture high fired wares, like electrical insulators and sanitary wares. Countries whose ceramics industries are less developed have to import these products, at great expense.  There are many reasons why high fired wares are not produced in places like north Africa, which has long traditions of ceramics production Some reasons are listed below in Table.1.

Polychrome glazed earthenware tile in the green mosque in Meknes, Morocco [1]   photo of the interior of the green mosque in Meknes [2]   drinking fountain in a mosque in Meknes [3]   photo of a mosaic ceiling made from polychrome ceramic tiles in the green mosque in Meknes [4]   Moroccan hand drum made from clay [5]  
Reason Comment
Kiln design Many countries still use the traditional up draught bottle kiln
Dudson bottle kiln as used in UK until the 1960's [6]   photo of traditiona live firel pottery kilns in Safi [7]   Traditional bottle kilns as used in Safi, Morocco in the 1980's[8]
photo of traditional pottery kilns in Safi [9a local potter at his wheel in Marakesh [10]
which wastes fuel because it doesn't retain heat well. It is quite likely that, even if more refractory clays were available, a temperature sufficient to vitrify the material would not be possible using the traditional kiln design.
Fuel available Traditionally, plant material like wood and straw, or animal dung is used to fuel pottery kilns in countries where electricity and gas are not available. Palm fronds are used as the fuel for pottery kilns in Safi and Marrakesh, Morocco. The fronds have a high oil content and explode spectacularly when introduced into the fire mouth of a kiln. Along with the associated thermal shocks, there are also repeated ground tremors to affect the fragile wares stacked in a kiln.  It is not unreasonable to assume that the impact of this firing method is detrimental to the quality of the end product.
Type of clay available Traditionally, earthenware clay is used which has a porous body and often has inclusions like gypsum.  A localised search to find a source of more refractory clays will require a high firing temperature capability in order to test the characteristics of the clay samples, ie; the temperature of vitrification, etc.
Traditional processes The traditional process for removing unwanted materials like gypsum, is not thorough enough and consequently a high volume of wares are broken Moroccan drum made from poor quality clay showing faults in the fired body[11]   Moroccan drum showing characteristic flaws resulting from Gypsom impurities in the clay [12] and become flawed as a result from these inclusions.
Available knowledge Traditional potteries are often family affairs and the specialist knowledge is handed down through the generations. Rarely do potters have a university education in ceramics, geology, mineralogy or chemistry.

The Proposition

This document puts forward the proposition that by making some modifications to the traditional process of ceramics production, we create the potential for locally produced vitrified ceramic wares. Advantages to be gained by modifying the production process are bulleted below.

For more information Continue to Kiln Geezer Page 2

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