The results of an extensive series of trials on a 100 tonnes per day cement kiln have provided a fundamental insight into the aerodynamics, burning mechanism and heat transfer in the sintering zone of such kilns. Accurate monitoring of the input and output variables has enabled mass and heat balances to be made on the system, and from these results it has been possible to isolate the areas where major fuel savings can be achieved. Slurry moisture, excess air and external heat losses are all variables where improvements and better control would reduce fuel consumption and increase the efficiency of rotary kilns. It has been shown that the external temperature profile of the kiln shell provides a useful indication of the various reaction regions that exist in the process cycle. From calculations of the heat lost from the shell, it has been shown that half the external heat losses occur from the sintering zone of the kiln. Specialized instrumentation has been developed to measure gas temperatures and extract combustion gas samples during the normal range of operation of the kiln. An analysis of these results has led to a formula to predict the length of the flame as influenced by the significant operating parameters. The measured gas concentrations have been used to predict the combustion rate within the flame, and a favourable comparison of this rate has been made with published data. The measurement of flame temperatures in the kiln has shown that the average flame temperature that may be encountered in a cement kiln is approximately 1800°C. Point temperatures of up to 2100°C were measured, and it was observed that increased excess air produced a shorter, hotter flame, but reduced the temperature of the combusted gases, resulting in a poorer quality product. A mathematical model has been developed to predict the gas and refractory temperature and heat flux profiles occurring in a rotary kiln sintering zone. The method is based on that of Hottel and Sarofim, but modified to account for the specialised firing conditions necessary for cement production. The model has been tested against the measured data obtained from the kiln trials, and the degree of agreement found to be encouraging. Use of this model should enable the cement, lime, and refractory industries to comprehend the effect of changes to operational variables, with a resulting improvement in heat utilisation, product quality and plant life.

Perlite is a glassy volcanic rock that contains approximately 70-75% silica and 12-18% alumina. There are very large perlite reserves in the world (~6700 million tons) and approximately two thirds of these is in Turkey. Due to its high amounts of silica and alumina, at the beginning of such a study, it seemed that it would be worth first to find out whether perlite possesses sufficient pozzolanic property when it is a finely divided form and then to investigate whether it could be used as a pozzolanic addition in producing blended cements. In this study, perlites from two different regions (izmir and Erzincan) were tested for their pozzolanic properties. After obtaining satisfactory results, grindability properties of the clinker, perlites and their different combinations were investigated. Several blended cements with different fineness values and different perlite amounts were produced by either intergrinding or separate grinding methods. The tests performed on the cement pastes and mortars containing the blended cements produced were as follows: Water requirement, normal consistency, setting time, soundness, compressive strength, rapid chloride permeability, resistance to sulfate attack and resistance to alkali-silica reactions. The results showed that Turkish perlites possess sufficient pozzolanic characteristics to be used in cement and concrete industry. Moreover, the properties tested in this study satisfied the requirements stated in the standards for blended cements. The durability of the mortars was found to be improved by 20% or more perlite incorporation.

The report investigates the feasibility of accessing waste heat at kiln 7 in the Cementa AB cement plant in Slite, Gotland. The background is provided, with a description of the cement manufacturing process. Most of the report concerns itself with the heat transfer capabilities of the plant, therefore a short description of the heat flow within the most essential equipment is provided. The investigation follows a set of steps to derive the conclusion. The first step investigates previous studies to obtain the three most feasible heat sources. The second step investigates the available heat of the selected sources. In the third step, accessing the source is discussed and investigated for both convection and radiation heat transfer methods. It also includes the sizing of the required heat exchangers. Using the new sources, the connection possibilities to existing infrastructure and its benefits are investigated in step four. The connections were made to the existing infrastructure used at kiln 8 for electrical generation and district heating supply. The selections of the most feasible solutions are provided based on heat recovery, payback period and practicality. The final step in the study provides for the final design, which consists of three possible connections or all of them combined. In the conclusion, the final design would provide for a reduction in oil burned, fuel consumption and CO2 emissions and an increase in electricity generated by the existing system. It is recommended that only one of the three connections be installed. / <p>The thesis was conducted at Cementa AB in Slite, Gotland. The supervisor at the plant was Fred Grönwall.</p>

This research investigates ways to reduce the carbon dioxide emissions from the cement industry. Cement is one of the largest sources of man-made greenhouse gases, contributing ~5% of the global total. 40% of emissions from cement come from the fuel used in the process, while the electricity used contributes a further 5%. The focus of the research is to find operational changes that can reduce emissions without the need for large capital investment. Three cement plants in the UK were investigated using four different mathematical models based on real data from the plants. A new metric for assessing the environmental impact of the fuel mix of a plant was proposed, and evidence indicates that it may be a better predictor of environmental performance than the metrics currently used in industry. The research found that consistently improving this fuel metric to best-observed levels, as well as reducing the excess air ratio to industry-standard levels had the potential to reduce fuel consumption by up to 7%, and fuel derived CO2 emissions by up to 12%. Increasing use of biomass to best-observed levels had the potential to reduce the net fuel derived CO2 emissions by up to 20%. Comparing the proposed improvements to the historic range of plant performance showed that this level of performance is within the normal operating range of the plants. A reduction of 2-4% in electricity costs and electricity derived emissions was also possible from operational changes. These savings would reduce operating costs as well as emissions, and require little to no capital investment, meaning they could be implemented directly. If successfully implemented in the near future the total savings by 2050 would be on a similar scale to those expected from much more expensive technology changes, such as upgrading to new cement plants, or installing carbon capture and storage technology.

Mining or industrial activity? This is not only an ancient question in Peruvian mining sector but a key issue for domestic and foreign private investment on cement. Since few years ago, cement manufacturing process has been being qualified and regulated by the Peruvian Mining Authority as a mining benefit process which implies the obligation to obtain a benefit mining concession previously. However, upon a review of the technical process aspects, the legal framework in force and a recent judgment enacted by the Constitutional Court of Peru regarding this topic, the position traditionally assumed by the Ministry of Energy and Miningcould be reconsidered. / ¿Es actividad minera o industrial? Ésta no es solo una antigua interrogante en el sector minero peruano sino una cuestión clave para la inversión privada local y extranjera del rubro cementero. Desde hace algunos años, la producción de cemento ha venido siendo calificada y regulada por la autoridad minera como beneficio minero, lo cual importa la obligación del titular de obtener previamente a la ejecución de la misma una concesión de beneficio. Sin embargo, a partir de una revisión de los aspectos técnicos del proceso, el marco normativo vigente y un reciente pronunciamiento del Tribunal Constitucional en relación a este tema, la tradicional posición adoptada por el Ministerio de Energía y Minas podría ser repensada.

L'objectif principal de cette thèse a été d'évaluer le potentiel de valorisation des cendres volantes de charbon issues de centrales thermiques Spreader Stoker (Cendres Volantes Spreader Stoker), dans la fabrication d'éco-ciments sur l'île de La Réunion. Nous avons dans un premier temps effectué une caractérisation physico-chimique des CVSS et vérifié leur réactivité. Deux voies de valorisation ont ensuite été retenues, l'une qui ne présente pas de valeur ajoutée mais qui permet de valoriser un volume important de CVSS par une stabilisation dans des matrices à base de ciment, l'autre qui offre une valeur ajoutée aux CVSS par une incorporation dans la fabrication de ciments composés. Le relargage en lixiviation a été étudié pour la première voie de valorisation retenue, puis, les effets des CVSS dans les matrices à base de ciment, notamment le rôle des imbrûlés contenus dans les cendres, ont été évalués aux états frais, durcissant et durci, suivi d'une petite exploitation numérique des données expérimentales. Enfin, une étude de durabilité sur des bétons à base de ciments de laboratoire a été faite par une approche comparative avec la pouzzolane naturelle, qui est actuellement utilisée pour la fabrication de ciments composés sur l'île de la Réunion. / The main objective of this project was to evaluate the potential of coal fly ash from Spreader Stoker thermal power plants (Spreader Stoker Coal Fly Ash) in the manufacture of eco-cements in Reunion Island. We first performed a physico-chemical characterization SSCFA and verified its reactivity. Two valorisation paths were chosen, one of which did not present any added value but which permit to value a large quantity of SSCFA by stabilization in cement-based matrices, the other which offers added value to SSCFA by incorporating it in the manufacture of composed cements. Leachate release was studied for the first path of valorisation, and then the effects of SSCFA in the cement matrices, especially the unburned particles contained in SSFCA, were evaluated in fresh, hardening and hardened states, followed by a small numerical exploitation of the experimental data. Finally, a sustainability study on concretes based on laboratory cements was made using a comparative approach with natural pozzolana, which is currently used for the manufacture of composite cements in Réunion Island.

This thesis explores the environmental and social responsibilities being increasingly shouldered by cement manufacturing sector and outlines a new approach for these companies to accept their responsibilities and to utilise professional approaches to address the economic, environmental and social dimensions of sustainable business. Managing these three dimensions in business translates corporate responsibility into an integrated responsibility for doing business profitably, ethically and in sustainable manner. This three-pronged approach is sometimes called the Triple Bottom Line. It helps companies to fulfil their more holistic Corporate Social Responsibility. A critical review of the literature led the thesis author to develop the theoretical framework for environmental and social reporting to proceed on TBL/CSR journey within the cement industry. Data were collected from TBL/CSR reports from cement companies on key environmental and social performances. Based upon those data, a questionnaire was developed to obtain more information from the leading worldwide cement companies. The combined results of the responses to the questionnaire and the quantitative data derived from the TBL/CSR reports were used to establish best practice benchmarks to serve as performance targets for the author's case study company, Oman Cement Company (OCC). The contribution to knowledge of this research is the summarisation and prioritisation of the cement industry's implementation of TBL/CSR management systems, which integrate the elements of TBL/CSR into their strategic plans and daily operational procedures. Guidelines were derived from the Global Reporting Initiative, the United Nations Global Compact and the new ISO 26000 standard, which promotes a new way of working towards innovation, value creation and incremental actions for transforming businesses to become more responsible. The contributions to practice of this research are the practical and procedural insights, gained by quantitative analysis of environmental and social indicators, into how cement companies are making improvements in their processes and products in response to climate change, economic, governmental regulations and social pressures for improvement. Based upon the findings, recommendations and timetables were developed and are being implemented within the OCC as it progresses on its TBL/CSR journey.

This thesis explores the environmental and social responsibilities being increasingly shouldered by cement manufacturing sector and outlines a new approach for these companies to accept their responsibilities and to utilise professional approaches to address the economic, environmental and social dimensions of sustainable business. Managing these three dimensions in business translates corporate responsibility into an integrated responsibility for doing business profitably, ethically and in sustainable manner. This three-pronged approach is sometimes called the Triple Bottom Line. It helps companies to fulfil their more holistic Corporate Social Responsibility. A critical review of the literature led the thesis author to develop the theoretical framework for environmental and social reporting to proceed on TBL/CSR journey within the cement industry. Data were collected from TBL/CSR reports from cement companies on key environmental and social performances. Based upon those data, a questionnaire was developed to obtain more information from the leading worldwide cement companies. The combined results of the responses to the questionnaire and the quantitative data derived from the TBL/CSR reports were used to establish best practice benchmarks to serve as performance targets for the author¿s case study company, Oman Cement Company (OCC). The contribution to knowledge of this research is the summarisation and prioritisation of the cement industry¿s implementation of TBL/CSR management systems, which integrate the elements of TBL/CSR into their strategic plans and daily operational procedures. Guidelines were derived from the Global Reporting Initiative, the United Nations Global Compact and the new ISO 26000 standard, which promotes a new way of working towards innovation, value creation and incremental actions for transforming businesses to become more responsible. The contributions to practice of this research are the practical and procedural insights, gained by quantitative analysis of environmental and social indicators, into how cement companies are making improvements in their processes and products in response to climate change, economic, governmental regulations and social pressures for improvement. Based upon the findings, recommendations and timetables were developed and are being implemented within the OCC as it progresses on its TBL/CSR journey.

Globally, cement industry is one of the most energy consuming industries. Moreover, production of emissions as dust, CO2, NOX, SO2 and heavy metals from manufacturing process is considered as environmentally harmful. However according to predictions of World Wildlife Found (WWF) and International Energy Agency (IEA) global cement demand is going to increase in next decades. For appropriate cement industry understanding data about production of harmful emissions were collected and cement production process was described in the thesis. The thesis mainly analyzed potential for Upper Austrian Company Kappa GmbH to install dedusting system on Czech or Slovak cement plants in next 2-3 years. Kappa´s dedusting systems are able to significantly reduced dust emissions exhaust from cement plants. However as for Company Kappa GmbH cement industry is a new industry branch in which company would like to operate in future, therefore certain objectives have be to overcome. The thesis found those objectives and gives recommendations for their solutions.

Made available in DSpace on 2011-05-04T12:36:26Z (GMT). No. of bitstreams: 0 Previous issue date: 2009 / A indústria cimenteira nacional, desde 1991, utiliza resíduos tóxicos gerados por outras empresas como combustível ou matéria prima alternativa, e justifica a prática, que resulta em substancial economia de recursos, como expressão de responsabilidade ambiental. Entretanto, a realidade demonstra sinais de impactos negativos sobre a saúde de trabalhadores e da população vizinha às fábricas, bem como ao meio ambiente.Este estudo ocupa-se de analisar as condições de trabalho e saúde a partir do discurso dos trabalhadores envolvidos na atividade em Cantagalo, RJ, comparando-as com a literatura científica disponível, depoimentos de autoridades, material jornalístico e gerado pelas empresas interessadas. A partir desta análise, pode-se comprovar que a atividade gera adoecimento, que é agravado pelas condições socioeconômicas locais, é banalizado pelo comportamento dos responsáveis por evitá-lo. É ocultado pela negligência de notificação às autoridades e é confundido pela valorização de duvidoso monitoramento biológico, indevidamente avaliado quanto às expressões clínicas típicas de intoxicações, gerando situações dúbias, que favorecem as empresas e lesam a população exposta. Há que fortalecer as instâncias locais de Meio Ambiente e Saúde, para que o tema seja discutido de forma ampla e conjunta, envolvendo atores responsáveis pela prática, órgãos ambientais e de saúde, e as populações expostas. É imperativo que haja nivelamento técnico e equidade de forças, condições fundamentais para que o processo se faça através da legitimação dos princípios da Saúde Coletiva e da Justiça Ambiental. / The Brazilian cement industry has since 1991 used toxic residues produced by other industries as either fuel or alternative raw material in the manufacture of cement. Such practice, while resulting in considerable saving of resources, is justified as a token of environmental responsibility and commitment. However, reality displays clear signs of negative impact on not only workers’ health and plants’ neighboring population, but the environment. This analysis investigates cement industry employees’ health and work conditions, in a comparative study between the discourse of the employees in a plant in Cantagalo, Rio de Janeiro, and the available scientific literature, authorities’ statements, newspaper articles and materials published by the companies at issue. The analysis proves that the activity causes illnesses, which are aggravated by the local socio-economical conditions; rendered banal by the behavior of those accountable for avoiding them; hidden by neglectful notification to authorities; and blurred by the overvaluation of doubtful biological monitoring, improperly assessed regarding the typical clinical manifestation of poisoning, generating dubious situations in favor of the involved companies and against the exposed population. It is necessary to strengthen Health and Environmental local offices, so that the subject is widely and jointly discussed, with the participation of those accountable for such practice, environment and health agencies and the exposed population. Technical leveling and power equity are mandatory and fundamental conditions for carrying out the process through legitimization of Collective Health and Environmental Justice principles.