<p>Development of products which can be produced from acountry's natural resources is very important as far as theindustrialization of a nation and saving foreign exchange isconcerned. Presently, industries in Uganda and the other statesin the Lake Victoria region import allrefractory-related-consumables, as the demand cannot be metlocally. Based on the abundance of ceramic raw materials forhigh temperature applications in the region and the demand forrefractories by industries it is pertinent to develop andmanufacture firebricks by exploiting the locally available rawmaterials.</p><p>This thesis thus, concerns the characterisation of ceramicraw mineral powders from in the Lake Victoria region, moreparticularly, Uganda, with the aim of developing firebrickrefractories from the minerals. Two main deposits of kaolin anda fireclay deposit, located in the Lake Victoria Region,Uganda, were investigated to assess their potential in themanufacture of refractory bricks. Raw- and processed samplepowders were investigated by means of x-ray diffraction (XRD),thermal analysis (DTA-TG) and Scanning Electron Microscopy(SEM). In addition, the chemical composition, particle sizedistribution, density, and surface area of the powders weredetermined.</p><p>A general production process scheme for manufacture offirebricks starting with raw powder minerals (Mutaka kaolin andMukono ball clay) was used to make six groups of samplefirebrick. Experimental results from the characterization offormulated sample bricks indeed reveal the viability ofmanufacturing firebricks from the raw minerals.Characterization of the sample bricks has been done fordetermination of physical and mechanical properties; density,shrinkage, porosity, water absorption, and phaseidentification. Formation of mullite, which is a principalcompound for aluminous refractories, is evidenced in thepowders with DTA tests and for the fired samples with XRD; thefired samples are dominated by mullite peaks.</p><p>Keywords: kaolin; clay; powders characterization; ceramics;mullite; Lake Victoria region;</p>

Development of products which can be produced from acountry's natural resources is very important as far as theindustrialization of a nation and saving foreign exchange isconcerned. Presently, industries in Uganda and the other statesin the Lake Victoria region import allrefractory-related-consumables, as the demand cannot be metlocally. Based on the abundance of ceramic raw materials forhigh temperature applications in the region and the demand forrefractories by industries it is pertinent to develop andmanufacture firebricks by exploiting the locally available rawmaterials. This thesis thus, concerns the characterisation of ceramicraw mineral powders from in the Lake Victoria region, moreparticularly, Uganda, with the aim of developing firebrickrefractories from the minerals. Two main deposits of kaolin anda fireclay deposit, located in the Lake Victoria Region,Uganda, were investigated to assess their potential in themanufacture of refractory bricks. Raw- and processed samplepowders were investigated by means of x-ray diffraction (XRD),thermal analysis (DTA-TG) and Scanning Electron Microscopy(SEM). In addition, the chemical composition, particle sizedistribution, density, and surface area of the powders weredetermined. A general production process scheme for manufacture offirebricks starting with raw powder minerals (Mutaka kaolin andMukono ball clay) was used to make six groups of samplefirebrick. Experimental results from the characterization offormulated sample bricks indeed reveal the viability ofmanufacturing firebricks from the raw minerals.Characterization of the sample bricks has been done fordetermination of physical and mechanical properties; density,shrinkage, porosity, water absorption, and phaseidentification. Formation of mullite, which is a principalcompound for aluminous refractories, is evidenced in thepowders with DTA tests and for the fired samples with XRD; thefired samples are dominated by mullite peaks. Keywords: kaolin; clay; powders characterization; ceramics;mullite; Lake Victoria region; / NR 20140805

<p>Development of products which can be produced from a country’s natural resources is very important as far as the industrialization of a nation and saving foreign exchange is concerned. Presently, industries in Uganda and the other states in the Lake Victoria region import all refractory-related-consumables, as the demand cannot be met locally. Based on the abundance of ceramic raw materials for high temperature applications in the region and the demand for refractories by industries it is pertinent to develop and manufacture firebricks by exploiting the locally available raw materials.</p><p>This thesis thus, concerns the characterisation of ceramic raw mineral powders from the Lake Victoria region, more particularly, Uganda, with the aim of developing firebrick refractories from the minerals. Two main deposits of kaolin and a ball clay deposit were investigated to assess their potential in the manufacture of refractory bricks. Raw- and processed sample powders were investigated by means of X-ray diffraction (XRD), thermal analysis (DTA-TG) and Scanning Electron Microscopy (SEM). In addition, the chemical composition, particle size distribution, density, and surface area of the powders were determined.</p><p>A comprehensive study on beneficiation of Mutaka kaolin was carried out using mechanical segregation of particles. The aim of the study was to explore other potential applications like in paper filling and coating. The beneficiation process improves the chemical composition of kaolin to almost pure, the major impurity being iron oxide.</p><p>A general production process scheme for manufacturing fireclay bricks starting with raw powder minerals (Mutaka kaolin and Mukono ball clay) was used to make six groups of sample fireclay brick. Experimental results from the characterization of formulated sample bricks indeed revealed the viability of manufacturing fireclay bricks from the raw minerals. Based on these results, industrial samples were formulated and manufactured at Höganäs Bjuf AB, Sweden. Kaolin from the Mutaka deposit was used as the main source of alumina while ball clay from Mukono was the main plasticizer and binder material. The formulated green body was consolidated by wet pressing and fired at 1350°C in a tunnel kiln. Characterization of the sintered articles was done by X-ray diffraction, scanning electron microscopy, and chemical composition (ICP-AES). In addition, technological properties related to thermal conductivity, thermal shock, alkali resistance, water absorption, porosity, shrinkage, permanent linear change (PLC), linear thermal expansion, refractoriness under load (RUL), and cold crushing strength were determined. The properties of the articles manufactured from the selected naturally occurring raw minerals reveal that the produced articles compare favourably with those of parallel types. Thus, the raw materials can be exploited for industrial production.</p>

Development of products which can be produced from a country’s natural resources is very important as far as the industrialization of a nation and saving foreign exchange is concerned. Presently, industries in Uganda and the other states in the Lake Victoria region import all refractory-related-consumables, as the demand cannot be met locally. Based on the abundance of ceramic raw materials for high temperature applications in the region and the demand for refractories by industries it is pertinent to develop and manufacture firebricks by exploiting the locally available raw materials. This thesis thus, concerns the characterisation of ceramic raw mineral powders from the Lake Victoria region, more particularly, Uganda, with the aim of developing firebrick refractories from the minerals. Two main deposits of kaolin and a ball clay deposit were investigated to assess their potential in the manufacture of refractory bricks. Raw- and processed sample powders were investigated by means of X-ray diffraction (XRD), thermal analysis (DTA-TG) and Scanning Electron Microscopy (SEM). In addition, the chemical composition, particle size distribution, density, and surface area of the powders were determined. A comprehensive study on beneficiation of Mutaka kaolin was carried out using mechanical segregation of particles. The aim of the study was to explore other potential applications like in paper filling and coating. The beneficiation process improves the chemical composition of kaolin to almost pure, the major impurity being iron oxide. A general production process scheme for manufacturing fireclay bricks starting with raw powder minerals (Mutaka kaolin and Mukono ball clay) was used to make six groups of sample fireclay brick. Experimental results from the characterization of formulated sample bricks indeed revealed the viability of manufacturing fireclay bricks from the raw minerals. Based on these results, industrial samples were formulated and manufactured at Höganäs Bjuf AB, Sweden. Kaolin from the Mutaka deposit was used as the main source of alumina while ball clay from Mukono was the main plasticizer and binder material. The formulated green body was consolidated by wet pressing and fired at 1350°C in a tunnel kiln. Characterization of the sintered articles was done by X-ray diffraction, scanning electron microscopy, and chemical composition (ICP-AES). In addition, technological properties related to thermal conductivity, thermal shock, alkali resistance, water absorption, porosity, shrinkage, permanent linear change (PLC), linear thermal expansion, refractoriness under load (RUL), and cold crushing strength were determined. The properties of the articles manufactured from the selected naturally occurring raw minerals reveal that the produced articles compare favourably with those of parallel types. Thus, the raw materials can be exploited for industrial production. / QC 20101029