Lime is not only an important building material but an essential ingredient in many industrial processes, such as agriculture and sugar manufacture. As a binder in the construction industry, it is simpler and cheaper to produce than Portland cement and yet just as effective for most building requirements in the Third World. As such, lime has a valuable role to play in the development process. The experience at Chenkumbi in central Malawi has demonstrated that vertical shaft kiln technology (VSK) can be adapted to small-scale production and produce high grade chemical lime economically. Another benefit of this technology over traditional methods is that coal or plantation-grown softwoods can be burnt in preference to native hardwoods — a process that has been leading to severe deforestation in the region.

INTRODUCTION 1
The case for lime
1. Raw Materials, applications and production 4
Raw materials; Applications; Theory of calcination and factors
affecting kiln design and operation; Kiln technology and choice
2. Background 10
Project location and environment; Social and economic survey;
Mineral resources; Fuel resources; Market for lime;
Preliminary investigations
3. Traditional production 13
Production cycle and technology; Input/output; Quality; Fuel
consumption and efficiency; Project implementation strategy
4. Natural draught vertical shaft kiln 17
Quarrying; Kiln firing; Slaking; Screening, milling and
bagging; Input/output; Quality; Fuel consumption and
thermal efficiency
5. Experimental forced-air kiln—Chenkumbi 20
Forced air technology; Chenkumbi Hills—experimental forced
air system; Kiln operation; Results; Input/output; Product
quality; Fuel consumption and thermal efficiency
6. Balaka forced-air system 25
Quarrying; Kiln design: operation and performance, Kiln
charging; Kiln operation; Forced air unit; Kiln discharge;
Input/output; Quality; Fuel consumption and thermal
efficiency; Experimental hydrator, milling and classification
plant
APPENDIX 1 32
Uses of lime and lime hydrate
APPENDIX 2: 33
Experimental forced-draught kiln trials
TABLES 34
1. Forced draught experimentation results;
2. Fuel consumption and efficiency;
3. Comparative capital costs;
4. Comparative incomes statement;
5. Comparative economic analysis
References 39

John Spiropoulos
John Spiropoulos is a graduate in the fields of building science and project management. He was instrumental in the establishment of a small scale building materials and minerals development company in Kanye, Botswana and was responsible for the project investigation and implementation of several building materials production projects including a small limeworks and a fired clay brickworks.