A produção de cimento gera um impacto ambiental negativo, principalmente relacionado à emissão de dióxido de carbono (CO2). O clínquer do cimento sulfoaluminato de cálcio belítico (CSAB) possui um menor teor de óxido de cálcio e é produzido com uma reduzida temperatura de sinterização (aproximadamente 200ºC a menos em relação ao clínquer Portland), sendo considerado mais eco-amigável. Para a produção do cimento CSAB são necessárias matérias-primas ricas em alumínio e convencionalmente a bauxita é o minério utilizado para compor a farinha, o que mais onera a produção desse tipo de cimento. Soma-se ainda o fato que a geração de resíduos e subprodutos industriais torna-se inerente aos processos e o coprocessamento de resíduos vem sendo cada vez mais utilizado por razões ambientais e energéticas. Logo, fontes alternativas de alumina são fundamentais para a viabilização deste cimento e o aproveitamento de resíduos agregaria um valor econômico e sustentável ao produto final. De modo estequiométrico, a bauxita pode ser completamente substituída pelo lodo de anodização do alumínio (LAA), o qual também pode complementar o conteúdo de alumínio de outros resíduos, valorizando-os. O objetivo deste estudo foi avaliar a produção e as propriedades de clínqueres/cimentos CSAB a partir da substituição da bauxita por cinza pesada e LAA. Para a caracterização das matérias-primas, clínqueres e cimentos nos estados anidro e hidratado foram utilizadas as seguintes técnicas: fluorescência de raios X; microscopia eletrônica de varredura e espectrometria por energia dispersiva; termogravimentria; calorimetria; e difração de raios X com refinamento pelo método de Rietveld. A partir dos resultados obtidos, a substituição da bauxita foi limitada a nível parcial devido à elevada formação de belita e periclásio. Nos clínqueres produzidos, foi constatado que a presença da cinza pesada favorece a formação da estrutura cristalina ortorrômbica da fase ye’elimita. A presença dos resíduos altera a quantificação das fases, porém não compromete a estabilização das mesmas. A presença dos resíduos na composição dos cimentos afeta o período inicial de hidratação devido à redução do conteúdo de ye’elimita. Nos clínqueres produzidos com cinza pesada, ocorre a formação de até 12,6% da fase alita a 1250ºC, principal constituinte do clínquer Portland. / Cement production generates high negative environmental impact, mainly associated to CO2 emissions. Calcium sulfoaluminate belite cement clinker (CSAB) has lower content of calcium oxide, and sintering reduced temperature (about 200°C lower than that used for Portland clinker), being considered as eco-friendly binder. For its production high amount of alumina is required, however the scarcity and high cost of bauxite make these cements costly. Additionally, the generation of waste and by-products becomes a drawback in the industrial processes and the coprocessing of wastes in cement plants is increasing for environmental and energy savings reasons. Alternative sources of alumina would add an economic and sustainable value to the final product and previous work has shown that the aluminum anodizing sludge can replace bauxite in the production process. Other sources of wastes can also be a possibility to increase the production and reduce the raw materials costs of these cements. Thus, the objective of this study was the evaluation of novel CSAB cements produced with bauxite replacement by bottom ash and aluminum anodizing sludge. CSAB cements were produced in the laboratory from different amounts of sludge and ashes. The raw materials, clinkers/cements and hydration products were physicaly-chemicaly and mechanical characterized. Results showed that the mineralogy composition of CSAB clinker was strongly affected due to the addition of bottom ash. The amount of bottom ash waste replacing bauxite controls the belite and periclase formation. Also it influences the early age hydration due the reduced ye’elimite formation and important changes in the crystalline structures of this phase occurs in the clinkers. Clinkers prepared from these replacement, are able to form 12.6% of alite (main phase Portland clinker), not normally found in CSAB clinkers, being sintered at 1250°C.

A produção de cimento gera um impacto ambiental negativo, principalmente relacionado à emissão de dióxido de carbono (CO2). O clínquer do cimento sulfoaluminato de cálcio belítico (CSAB) possui um menor teor de óxido de cálcio e é produzido com uma reduzida temperatura de sinterização (aproximadamente 200ºC a menos em relação ao clínquer Portland), sendo considerado mais eco-amigável. Para a produção do cimento CSAB são necessárias matérias-primas ricas em alumínio e convencionalmente a bauxita é o minério utilizado para compor a farinha, o que mais onera a produção desse tipo de cimento. Soma-se ainda o fato que a geração de resíduos e subprodutos industriais torna-se inerente aos processos e o coprocessamento de resíduos vem sendo cada vez mais utilizado por razões ambientais e energéticas. Logo, fontes alternativas de alumina são fundamentais para a viabilização deste cimento e o aproveitamento de resíduos agregaria um valor econômico e sustentável ao produto final. De modo estequiométrico, a bauxita pode ser completamente substituída pelo lodo de anodização do alumínio (LAA), o qual também pode complementar o conteúdo de alumínio de outros resíduos, valorizando-os. O objetivo deste estudo foi avaliar a produção e as propriedades de clínqueres/cimentos CSAB a partir da substituição da bauxita por cinza pesada e LAA. Para a caracterização das matérias-primas, clínqueres e cimentos nos estados anidro e hidratado foram utilizadas as seguintes técnicas: fluorescência de raios X; microscopia eletrônica de varredura e espectrometria por energia dispersiva; termogravimentria; calorimetria; e difração de raios X com refinamento pelo método de Rietveld. A partir dos resultados obtidos, a substituição da bauxita foi limitada a nível parcial devido à elevada formação de belita e periclásio. Nos clínqueres produzidos, foi constatado que a presença da cinza pesada favorece a formação da estrutura cristalina ortorrômbica da fase ye’elimita. A presença dos resíduos altera a quantificação das fases, porém não compromete a estabilização das mesmas. A presença dos resíduos na composição dos cimentos afeta o período inicial de hidratação devido à redução do conteúdo de ye’elimita. Nos clínqueres produzidos com cinza pesada, ocorre a formação de até 12,6% da fase alita a 1250ºC, principal constituinte do clínquer Portland. / Cement production generates high negative environmental impact, mainly associated to CO2 emissions. Calcium sulfoaluminate belite cement clinker (CSAB) has lower content of calcium oxide, and sintering reduced temperature (about 200°C lower than that used for Portland clinker), being considered as eco-friendly binder. For its production high amount of alumina is required, however the scarcity and high cost of bauxite make these cements costly. Additionally, the generation of waste and by-products becomes a drawback in the industrial processes and the coprocessing of wastes in cement plants is increasing for environmental and energy savings reasons. Alternative sources of alumina would add an economic and sustainable value to the final product and previous work has shown that the aluminum anodizing sludge can replace bauxite in the production process. Other sources of wastes can also be a possibility to increase the production and reduce the raw materials costs of these cements. Thus, the objective of this study was the evaluation of novel CSAB cements produced with bauxite replacement by bottom ash and aluminum anodizing sludge. CSAB cements were produced in the laboratory from different amounts of sludge and ashes. The raw materials, clinkers/cements and hydration products were physicaly-chemicaly and mechanical characterized. Results showed that the mineralogy composition of CSAB clinker was strongly affected due to the addition of bottom ash. The amount of bottom ash waste replacing bauxite controls the belite and periclase formation. Also it influences the early age hydration due the reduced ye’elimite formation and important changes in the crystalline structures of this phase occurs in the clinkers. Clinkers prepared from these replacement, are able to form 12.6% of alite (main phase Portland clinker), not normally found in CSAB clinkers, being sintered at 1250°C.

A produção de cimento gera um impacto ambiental negativo, principalmente relacionado à emissão de dióxido de carbono (CO2). O clínquer do cimento sulfoaluminato de cálcio belítico (CSAB) possui um menor teor de óxido de cálcio e é produzido com uma reduzida temperatura de sinterização (aproximadamente 200ºC a menos em relação ao clínquer Portland), sendo considerado mais eco-amigável. Para a produção do cimento CSAB são necessárias matérias-primas ricas em alumínio e convencionalmente a bauxita é o minério utilizado para compor a farinha, o que mais onera a produção desse tipo de cimento. Soma-se ainda o fato que a geração de resíduos e subprodutos industriais torna-se inerente aos processos e o coprocessamento de resíduos vem sendo cada vez mais utilizado por razões ambientais e energéticas. Logo, fontes alternativas de alumina são fundamentais para a viabilização deste cimento e o aproveitamento de resíduos agregaria um valor econômico e sustentável ao produto final. De modo estequiométrico, a bauxita pode ser completamente substituída pelo lodo de anodização do alumínio (LAA), o qual também pode complementar o conteúdo de alumínio de outros resíduos, valorizando-os. O objetivo deste estudo foi avaliar a produção e as propriedades de clínqueres/cimentos CSAB a partir da substituição da bauxita por cinza pesada e LAA. Para a caracterização das matérias-primas, clínqueres e cimentos nos estados anidro e hidratado foram utilizadas as seguintes técnicas: fluorescência de raios X; microscopia eletrônica de varredura e espectrometria por energia dispersiva; termogravimentria; calorimetria; e difração de raios X com refinamento pelo método de Rietveld. A partir dos resultados obtidos, a substituição da bauxita foi limitada a nível parcial devido à elevada formação de belita e periclásio. Nos clínqueres produzidos, foi constatado que a presença da cinza pesada favorece a formação da estrutura cristalina ortorrômbica da fase ye’elimita. A presença dos resíduos altera a quantificação das fases, porém não compromete a estabilização das mesmas. A presença dos resíduos na composição dos cimentos afeta o período inicial de hidratação devido à redução do conteúdo de ye’elimita. Nos clínqueres produzidos com cinza pesada, ocorre a formação de até 12,6% da fase alita a 1250ºC, principal constituinte do clínquer Portland. / Cement production generates high negative environmental impact, mainly associated to CO2 emissions. Calcium sulfoaluminate belite cement clinker (CSAB) has lower content of calcium oxide, and sintering reduced temperature (about 200°C lower than that used for Portland clinker), being considered as eco-friendly binder. For its production high amount of alumina is required, however the scarcity and high cost of bauxite make these cements costly. Additionally, the generation of waste and by-products becomes a drawback in the industrial processes and the coprocessing of wastes in cement plants is increasing for environmental and energy savings reasons. Alternative sources of alumina would add an economic and sustainable value to the final product and previous work has shown that the aluminum anodizing sludge can replace bauxite in the production process. Other sources of wastes can also be a possibility to increase the production and reduce the raw materials costs of these cements. Thus, the objective of this study was the evaluation of novel CSAB cements produced with bauxite replacement by bottom ash and aluminum anodizing sludge. CSAB cements were produced in the laboratory from different amounts of sludge and ashes. The raw materials, clinkers/cements and hydration products were physicaly-chemicaly and mechanical characterized. Results showed that the mineralogy composition of CSAB clinker was strongly affected due to the addition of bottom ash. The amount of bottom ash waste replacing bauxite controls the belite and periclase formation. Also it influences the early age hydration due the reduced ye’elimite formation and important changes in the crystalline structures of this phase occurs in the clinkers. Clinkers prepared from these replacement, are able to form 12.6% of alite (main phase Portland clinker), not normally found in CSAB clinkers, being sintered at 1250°C.

Direct compression has gained significant interest since its advent in the late 1950's due to its potential ease compared to wet granulation. The primary prerequisites for powders used in direct compression are (i) good flow properties (ii) good compressibility and (iii) an acceptable dilution potential to accommodate a relative high percentage of active ingredient. Several filler/binders have been manufactured especially for direct compression and co–processing is one of the recent methods used to produce good compressible excipients with acceptable flow properties. In this study, lactose–based filler/binders were used which included simple and modified lactose materials (Granulac, Lactopress, Flowlac and Tablettose) as well as co–processed excipients (Starlac, Cellactose and Microcelac). A comprehensive literature study on direct compression revealed the importance of the physical properties of filler/binders such as interparticle forces, particle shape, particle size and distribution, powder density, particle surface structure and particle packing geometry which influence the flow of powders. All the materials were subjected to the various tests available to evaluate powder flow, namely (i) angle of repose (AoR), (ii) critical orifice diameter (COD), (iii) flow rate and percentage compressibility (%C) in terms of the powders' bulk and tap densities. The results of these tests confirmed the expected flow properties of the various filler/binders, with only one material exhibiting extremely poor flow properties. The following rank order in terms of all flow tests conducted was established; Starlac >> Microcelac ~ Flowlac >> Cellactose > Tablettose > Lactopress >>> Granulac. The co–processed filler/binders presented with superior flow compared to the other lactose–based materials. During the next phase of the study, the compaction properties of the various fillers were evaluated, employing direct compression. Compacts of pure filler were tabletted on an eccentric tablet press at different compression pressures (manipulated by the upper punch setting of the tablet press). The modified lactose filler/binders (Lactopress, Flowlac and Tablettose) exhibited unexpectedly poor compression profiles, where the co–processed filler/binders (Starlac, Cellactose and Microcelac) produced compacts with acceptable appearance and compact properties. Two lubricants (Mg–St or Pruv), which were tested separately in formulations were added since no compacts could be produced from the pure filler/binders. None of the modified lactose filler/binders, in combination with a lubricant, were able to produce an acceptable compact, since lamination occurred during compression. The co–processed filler/binders produced satisfactory compacts with the addition of a lubricant, but lactose–cellulose fillers (Cellactose and Microcelac) also required the inclusion of a disintegrant (Ac–Di–Sol) to induce satisfactory compact disintegration. Poor compressible active ingredients (paracetamol), which exhibit very poor flow properties, are usually difficult to use during direct compression. Many excipients (tested in this study) are formulated to accommodate these drugs and produce acceptable functional tablets. After identifying the best filler/binders (co–processed fillers), according to their flow and compressible properties, paracetamol was added to the formulations. During a pilot study, the percentage paracetamol these fillers could accommodate in a 400 mg tablet was determined. Both Microcelac and Cellactose could accommodate 24.5% w/w paracetamol, whilst Starlac could only accommodated 19.5% w/w. Paracetamol is well known for its tendency to cause tablet capping and lamination. An acceptable upper punch setting range (20–22) was chosen for tabletting, followed by quality control tests done. All three formulations produced suitable tablets for testing and exhibited good tablet properties. All tablets disintegrated within two minutes, with hardness profiles between 120 N and 148 N and friability percentages less than 1%. Dissolution studies, however, are probably the ultimate test to distinguish between the capability of filler/binders to release the optimum percentage drug after disintegration. Dissolution studies were done on all three formulations using the AUC (area under the curve) and IDR (initial drug release) as parameters to evaluate drug release. All tablets exhibited high initial dissolution rates (between 0.018 - 0.023 mg/min/ml) and 100% drug release was observed. Starlac presented with a lower amount of drug released compared to the other two, but can be explained by the lower percentage (19.5%) paracetamol present in the formulation. It was once again confirmed that the physical and compressible properties of potential directly compressible filler/binders play a major role in direct compression. It was concluded that co–processed filler/binders (Starlac, Microcelac and Cellactose) definitely exhibited better tabletting properties during direct compression. They were able to accommodate a certain percentage of paracetamol, although it was expected that they would accommodate a higher amount (at least 50% of total tablet weight). / Thesis (M.Sc. (Pharmaceutics))--North-West University, Potchefstroom Campus, 2011.

Direct compression has gained significant interest since its advent in the late 1950's due to its potential ease compared to wet granulation. The primary prerequisites for powders used in direct compression are (i) good flow properties (ii) good compressibility and (iii) an acceptable dilution potential to accommodate a relative high percentage of active ingredient. Several filler/binders have been manufactured especially for direct compression and co–processing is one of the recent methods used to produce good compressible excipients with acceptable flow properties. In this study, lactose–based filler/binders were used which included simple and modified lactose materials (Granulac, Lactopress, Flowlac and Tablettose) as well as co–processed excipients (Starlac, Cellactose and Microcelac). A comprehensive literature study on direct compression revealed the importance of the physical properties of filler/binders such as interparticle forces, particle shape, particle size and distribution, powder density, particle surface structure and particle packing geometry which influence the flow of powders. All the materials were subjected to the various tests available to evaluate powder flow, namely (i) angle of repose (AoR), (ii) critical orifice diameter (COD), (iii) flow rate and percentage compressibility (%C) in terms of the powders' bulk and tap densities. The results of these tests confirmed the expected flow properties of the various filler/binders, with only one material exhibiting extremely poor flow properties. The following rank order in terms of all flow tests conducted was established; Starlac >> Microcelac ~ Flowlac >> Cellactose > Tablettose > Lactopress >>> Granulac. The co–processed filler/binders presented with superior flow compared to the other lactose–based materials. During the next phase of the study, the compaction properties of the various fillers were evaluated, employing direct compression. Compacts of pure filler were tabletted on an eccentric tablet press at different compression pressures (manipulated by the upper punch setting of the tablet press). The modified lactose filler/binders (Lactopress, Flowlac and Tablettose) exhibited unexpectedly poor compression profiles, where the co–processed filler/binders (Starlac, Cellactose and Microcelac) produced compacts with acceptable appearance and compact properties. Two lubricants (Mg–St or Pruv), which were tested separately in formulations were added since no compacts could be produced from the pure filler/binders. None of the modified lactose filler/binders, in combination with a lubricant, were able to produce an acceptable compact, since lamination occurred during compression. The co–processed filler/binders produced satisfactory compacts with the addition of a lubricant, but lactose–cellulose fillers (Cellactose and Microcelac) also required the inclusion of a disintegrant (Ac–Di–Sol) to induce satisfactory compact disintegration. Poor compressible active ingredients (paracetamol), which exhibit very poor flow properties, are usually difficult to use during direct compression. Many excipients (tested in this study) are formulated to accommodate these drugs and produce acceptable functional tablets. After identifying the best filler/binders (co–processed fillers), according to their flow and compressible properties, paracetamol was added to the formulations. During a pilot study, the percentage paracetamol these fillers could accommodate in a 400 mg tablet was determined. Both Microcelac and Cellactose could accommodate 24.5% w/w paracetamol, whilst Starlac could only accommodated 19.5% w/w. Paracetamol is well known for its tendency to cause tablet capping and lamination. An acceptable upper punch setting range (20–22) was chosen for tabletting, followed by quality control tests done. All three formulations produced suitable tablets for testing and exhibited good tablet properties. All tablets disintegrated within two minutes, with hardness profiles between 120 N and 148 N and friability percentages less than 1%. Dissolution studies, however, are probably the ultimate test to distinguish between the capability of filler/binders to release the optimum percentage drug after disintegration. Dissolution studies were done on all three formulations using the AUC (area under the curve) and IDR (initial drug release) as parameters to evaluate drug release. All tablets exhibited high initial dissolution rates (between 0.018 - 0.023 mg/min/ml) and 100% drug release was observed. Starlac presented with a lower amount of drug released compared to the other two, but can be explained by the lower percentage (19.5%) paracetamol present in the formulation. It was once again confirmed that the physical and compressible properties of potential directly compressible filler/binders play a major role in direct compression. It was concluded that co–processed filler/binders (Starlac, Microcelac and Cellactose) definitely exhibited better tabletting properties during direct compression. They were able to accommodate a certain percentage of paracetamol, although it was expected that they would accommodate a higher amount (at least 50% of total tablet weight). / Thesis (M.Sc. (Pharmaceutics))--North-West University, Potchefstroom Campus, 2011.