Small Scale Production of Lime for Building by John Spiropoulos A Publication of the Deutsches Zentrum für Entwicklungstechnologien - GATE in: Deutsche Gesellschaft für Technische Zusammenarbeit (GTZ) GmbH - 1985 The Author: 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. CIP-Kurztitelaufnahme der Deutschen Bibliothek Spiropoulos, John: Small scale production of lime for building: a publ. Of Dt. Zentrum für Entwicklungstechnologien - GATE in: Dt. Ges. Für Techn. Zusammenarbeit (GTZ) GmbH / John Spiropoulos. - Braunschweig; Wiesbaden: Vieweg., 1985. ISBN 3-528-02016-4 All rights reserved. © Deutsche Gesellschaft für Technische Zusammenarbeit (GTZ) GmbH, Eschborn 1985 Published by Friedr. Vieweg & Sohn Verlagsgesellschaft mbH, Braunschweig Printed in the Federal Republic of Germany by Lengericher Handelsdruckerei, Lengerich ISBN 3-528-02016-4 Content Introduction............................................................................................................4 1. General Information...........................................................................................6 1.1 Geological description of limestone........................................................................... 6 1.2 Chemical composition of limestone........................................................................... 6 1.3 Physical characteristics of limestone......................................................................... 6 1.4 Classification of limestone......................................................................................... 7 1.5 Chemical reactions in the production of lime ............................................................. 7 1.6 Common uses of lime in developing countries .......................................................... 8 1.6.1 Use of lime in building construction.....................................................................................8 1.6.2 Soil stabilization in road construction ..................................................................................9 1.6.3 Lime in agriculture ...............................................................................................................9 2. Project Investigation and Implementation.....................................................11 2.1 Schematic representation ....................................................................................... 11 2.2 Socio-economic study............................................................................................. 11 2.3 Mineral resource investigations............................................................................... 12 2.4 Site surveys ............................................................................................................ 12 2.5 Market study ........................................................................................................... 13 2.6 Location of production site and decision on technological level............................... 13 2.7 Production plan....................................................................................................... 13 2.8 Financing ................................................................................................................ 15 2.9 Marketing plan ........................................................................................................ 16 2.10 Example economic feasibility calculation............................................................... 16 2.11 Project implementation programme and resource plans........................................ 21 2.12 Project implementation.......................................................................................... 21 3. Technical and Production Information ..........................................................24 3.1 Quarrying and kiln feed preparation ........................................................................ 24 3.1.1 Selection of site .................................................................................................................24 3.1.2 Quarry plan........................................................................................................................25 3.1.3 Quarrying...........................................................................................................................26 3.2 Fuels.......................................................................................................................27 3.2.1 Heat requirements and thermal efficiency.........................................................................27 3.2.2 Fuel types ..........................................................................................................................28 3.3 Limeburning ............................................................................................................ 30 3.3.1 Principles of limeburning and factors effecting the production of lime..............................30 3.3.1.1 Physical factors...........................................................................................................30 3.3.1.2 Density, porosity and crystal structure........................................................................31 3.3.1.3 Heat and temperature.................................................................................................32 3.3.2 Kiln designs .......................................................................................................................33 3.3.2.1 Batch fired kilns...........................................................................................................33 3.3.2.2 Continous kilns............................................................................................................38 3.3.3 Vertical shaft mixed feed kilns, design and construction...................................................43 3.3.3.1 Shape and dimensions ...............................................................................................44 3.3.3.2 Kiln construction..........................................................................................................44 3.3.4 Continuously operated, mixed feed kiln ............................................................................50 3.3.4.1 Design factors.............................................................................................................50 3.3.4.2 Operational factors .....................................................................................................50 3.3.4.3 Problems -causes and remedies ................................................................................51 2 3.4 Hydration ................................................................................................................ 53 3.4.1 Water for hydration............................................................................................................53 3.4.2 Rate of hydration ...............................................................................................................54 3.4.3 Hydration of magnesian limes...........................................................................................54 3.4.4 Methods of slaking.............................................................................................................54 3.4.4.1 Hand slaking ...............................................................................................................54 3.4.4.2 Mechanical slaking......................................................................................................55 3.4.5 Causes and effects of a badly hydrated lime ....................................................................56 4. Testing and Quality Control............................................................................57 4.1 Geological investigation (the geological surveying) ................................................. 57 4.2 Laboratory testing ................................................................................................... 57 4.3 Field testing ............................................................................................................ 58 4.4 Quality control......................................................................................................... 58 4.5 Tests.......................................................................................................................60 5. Technical Account of a 3 Tonne/Day Limeburning Operation in Moshaneng, Botswana........................................................................................63 5.1 Background............................................................................................................. 63 5.2 Production process ................................................................................................. 63 5.3 Trials....................................................................................................................... 64 5.3.1 Observations during firing trials.........................................................................................65 5.3.2 Batch versus continuous operation ...................................................................................65