The goal of the thesis is to evaluate if developed phase chemical process models for cement clinker and lime production processes are reliable to use as predictive tools in understanding the changes when introducing sustainability measures. The thesis describes the development of process simulation models in the application of sustainability measures as well as the evaluation of these models. The motivation for developing these types of models arises from the need to predict the chemical and the process changes in the production process, the impact on the product quality and the emissions from the flue gas. The main chemical reactions involving the major elements (calcium, silicon, aluminium and iron) are relatively well known. As for the minor elements, such as sodium and potassium metals, sulphur, chlorine, phosphorus and other trace elements, their influence on the main reactions and the formation of clinker minerals is not entirely known. When the concentrations of minor and trace elements increase due to the use of alternative materials and fuels, a model that can accurately predict their chemistry is invaluable. For example, the shift towards using less carbon intensive fuels and more biomass fuels often leads to an increased phosphorus concentration in the products. One way to commit to sustainable development methods in cement clinker and lime production is to use new combustion technologies, which increase the ability to capture carbon dioxide. Introducing oxy-fuel combustion achieves this, but at the same time, the overall process changes in many other ways. Some of these changes are evaluated by the models in this work. In this thesis, a combination of the software programs Aspen Plus™ and ChemApp™ constitutes the simulation model. Thermodynamic data from FACT are evaluated and adjusted to suit the chemistry of cement clinker and lime. The resulting model has been verified for one lime and two cement industrial processes. Simulated scenarios of co-combustion involving different fuels and different oxy-fuel combustion cases in both cement clinker and lime rotary kiln production are described as well as the influence of greater amounts of phosphorus on the cement clinker quality.

This thesis investigates sustainability measures for quicklime and cement clinker production. It is the aim of this thesis to contribute to the effort of creating a more sustainable modus of industrial production. The methods used comprises process simulations through multicomponent chemical equilibrium calculations, fuel characterization and raw materials characterization through dynamic rate thermogravimetry. The investigated measures relate to alternative fuels, co-combustion, oxygen enrichment, oxyfuel combustion, mineral carbonation and optimizing raw material mixes based on thermal decomposition characteristics. The predictive multicomponent chemical equilibrium simulation tool developed has been used to investigate new process designs and combustion concepts. The results show that fuel selection and oxygen enrichment influence energy efficiency, and that oxyfuel combustion and mineral carbonation could allow for considerable emission reductions at low energy penalty, as compared to conventional post-combustion carbon dioxide capture technologies. Dynamic rate thermogravimetry, applied to kiln feed limestone, allows for improved feed analysis with a deeper understanding of how mixing of different feed materials will affect the production processes. The predictive simulation tool has proven to be of practical value when planning and executing production and full scale campaigns, reducing costs related to trial and error. The main conclusion of this work is that several measures are available to increase the sustainability of the industry.

This thesis aims to burn raw material with a lower content of carbonate component for the production of Portland cement. Substitution of carbonate component is done by fluidized fly ash. The model cements are tested of basic technological properties and the hydration process is observed.

The Master’s thesis is focused on a study of the effect of increased content of heavy metals present in a raw meal on the formation and properties of prepared clinker and acquired cement. Main attention is devoted to changes on the physical, mechanical, microstructural and hydration properties. The theoretical part contains an overview of clinker minerals occurring in Portland cement including the possibility of incorporation of heavy metals into their structure and affecting the properities of the cement. In the experimental part, there is compared the effect of heavy metal oxides on the composition and hydration properties of portland clinker and physical-mechanical and microstructural properities of cement pastes prepared from this clinker.

Cement production is responsible for around 7% of the global anthropogenic carbon dioxide emissions. More than half of these emissions are due to the unavoidable release of carbon dioxide upon thermal decomposition of the main raw material limestone. Many different options for carbon capture are currently being investigated to lower emissions, and one potential route to facilitate carbon capture could be the implementation of an electrified separate calcination step. However, potential effects on the phase composition of cement clinker need to be investigated, which is the aim of the present study. Phases of special interest are alite, belite, aluminate, ferrite, calcite, and lime.  The phase composition during clinker formation was examined through HT-XRD lab-scale experiments, allowing the phase transformations to be observed in situ. Two different methods of separate calcination were investigated, one method in which the raw meal was calcined separately, and one method where the limestone was calcined separately. The former yielded an alite amount similar to that of the reference experiments, whereas the latter method yielded a lower amount. It could, unfortunately, not be excluded that the difference was due to poor experimental conditions, and additional experiments are needed to investigate the matter further. The study does, however, indicate that a calcined raw meal might be used to produce a clinker of similar phase composition concerning major phases belite, aluminate, ferrite, alite, and free lime. A raw meal containing calcined limestone might, however, need longer residence time at clinkering temperature too obtain similar phase composition. In addition, a raw meal containing calcined limestone was observed to be carbonated to a greater extent upon reheating than a calcined raw meal. Further experiments are needed to fully understand the effects on clinker composition of an electrified separate calcination step, and several improvements to the experimental method are given in the study.

Concrete, one of the world’s most important building materials is formed when cement is mixed with aggregates and reacts with water. The reaction is called hydration. Production of cement involves conversion of limestone and clay minerals into cement clinker in a kiln at high temperatures. The process requires high amounts of energy and causes substantial carbon emissions due to calcination of limestone and combustion of fuels, and the need for carbon neutral clinker products have never been greater. Heidelberg Materials Cement Sverige AB has multiple ongoing projects to reduce the carbon footprint of their clinker products. In essence, this is made possible by diluting the clinker with supplementary cementitious materials (SCM), electrification of the kiln, and carbon capture and storage (CCS). During tests of such applications in pilot and industrial scales it is necessary to evaluate the cement clinker manufactured for its ability to act as a binder in concrete. Such properties are collectively termed hydraulic reactivity and depend on the rate and extent to which the anhydrous components (alite, belite, aluminate, ferrite) in the cement react with water to form structural strength. The primary hydration products are Calcium-silicate-hydrate (C-S-H) and portlandite (CH). Due to lack of routines for clinker reactivity testing, especially for small batches, new methods and guidelines for reactivity tests has become highly sought after. Therefore, this work has aimed to develop a method for laboratory grinding of clinkers and then to study their hydration reactions by isothermal conductive calorimetry (ICC), Rietveld refinement quantitative x-ray diffraction (XRD) and thermogravimetric analysis (TGA). The goal of the work has been to provide a grinding method for laboratory cement preparation and a protocol for clinker reactivity evaluation. A fundamental requirement has been that the results of the methods must be comparable with Heidelberg Materials’ conventional standard methods. The work was initiated with a literature review on cement clinker manufacture, its hydration kinetics and reactivity tests. Industrial reference clinkers were used to develop the grinding method, and finally, reactivity tests with ICC, XRD and TGA were conducted on multiple clinkers of different origins. The grinding method developed in this work gave a fineness resembling the conventional grinding method but slightly coarser. Consequently, the heats measured in ICC for the clinkers studied were also comparable to previous analyses by conventional methods. This was a direct result of the reactivity being dependent on the specific surface area of the cement particles. Thanks to this, the newly developed grinding method and reactivity test by ICC may be incorporated into Heidelberg Materials standard methods. Hydrates formation and clinker mineral consumption were studied in XRD and TGA. The two techniques were used as cross-validation of one another. In summary, these yielded more in-depth information about the hydration of cements than provided by ICC and gave insights into what minerals and reactions were responsible for each clinker’s reactivity. However, the XRD and TGA results contained significant errors at some times, and further development is necessary before using them as part of a standard routine. This was mainly due to errors tied to sample preparation. Some necessary improvements are better Rietveld refinement, prevention of XRD sample carbonation, and addition of a separate ettringite analysis in TGA. Despite this, the methods show great promise, as highly correlating results were reached between methods when the sources of error were managed. For future work, it is suggested that the protocol is expanded and applied to also evaluate SCM’s. / Betong är ett av världens viktigaste byggmaterial och bildas när cement blandat med aggregat reagerar med vatten. Reaktionen kallas hydratation. Cement i sin tur tillverkas genom omvandling av kalksten och lermineraler till cementklinker vid hög temperatur i en roterugn. Denna process är mycket energikrävande och genererar stora koldioxidutsläpp från råmaterialen och bränslet. Till följd av detta har ett starkt och omedelbart behov av klimatvänliga klinkerprodukter uppstått. Heidelberg Materials Cement Sverige AB arbetar ständigt med att hitta nya lösningar till produktionen för att minska dess klimatavtryck. En viktig del i denna minskning är att späda ut klinkern med alternativa bindemedel (SCM), elektrifiering av bränningsprocessen och uppfångning samt lagring av koldioxid (CCS). Förändringar i den industriella processen förändrar dock klinkern vilket kan påverka cementets förmåga att agera som bindemedel i betong. Dessa egenskaper kallas kollektivt för hydraulisk reaktivitet, och beror på både hastigheten och i vilken utsträckning klinkermineralerna alit, belit, aluminat och ferrit hydratatiseras för att bilda calcium-silikat-hydrat (C-S-H) och portlandit (CH) och på så vis skapa tryckhållfasthet. I och med försök på industriell- och pilotnivå har det blivit önskvärt att kunna utvärdera reaktiviteten hos klinker. Eftersom det idag delvis fattas rutiner för detta, så har detta arbete syftat till att utveckla en metod för laboratoriemalning av klinker i små batcher, samt att studera hydratationen av den malda klinkern med isotermisk konduktions kalorimetri (ICC), kvantitativ röntgendiffraktion med Rietveld metoden (XRD) och termogravimetrisk analys (TGA). Projektets mål har varit att färdigställa en sådan malningsmetod och att förse företaget med ett protokoll för utvärdering av reaktiviteten. Ett grundläggande krav för de utvecklade metoderna är att deras resultat ska vara jämförbara med Heidelberg Materials konventionella standardmetoder. Arbetet sjösattes med en litteraturstudie på ämnet klinkerproduktion, cementhydratation och reaktivitetstester av cement och alternativa bindemedel. Därefter utvecklades malningsmetoden med hjälp av industriell referensklinker. Slutligen testades dessa och ett antal andra klinkers, både framställda i laboratorieugn och industriellt, för reaktivitet med ICC, XRD och TGA. Malningsmetodens resultat blev något grövre, men ändå i hög grad jämförbart med dagens konventionella metod. Denna skillnad är dock liten och förutsägbar. Därför blev också uppmätt värme i ICC jämförbart med tidigare värden från den konventionella metoden. På grund av den något grövre malningen, vilket leder till mindre reaktionsyta för cementet-vatten-fasen, så blev värmeutvecklingen i ICC alltid något lägre jämfört med den konventionella metoden, dock aldrig utanför gränserna för vad standardmetodens reproducerbarhet är. Tack vare detta dras slutsatsen att protokollet kommer vara relevant och lämpligt för introduktion i industrin. Cementens reaktivitet studerades också i högre detalj med hjälp av TGA och XRD, vilka användes för extern validering av varandra. Medan dessa metoder ger viktig information om varje enskild fas i den åldrande pastan, så är slutsatsen att de är i fortsatt behov av utveckling. Detta har mest att göra med provberedningen. Nödvändiga förbättringar är bättre Rietveld kvantifiering med fler prover och försiktigare provberedning för att förhindra karbonatisering av cementpastorna. TGA metoden kan enkelt förbättras och uppnå avsevärt bättre resultat endast genom införandet av en separat analys av ettringit. Trots detta så visar de två metoderna hög korrelation mellan varandra då provberedningen fungerat som avsett, vilket är lovande och innebär att man med dessa enkla förslag kan skapa en metod som ger information om ett cements reaktivitet i mycket högre detalj än vad som är möjligt med dagens standardmetoder. Som förslag till framtida arbeten ges att protokollet bör utökas till att även bedöma prestandan av alternativa bindemedel vid spädning av klinker. / Cemzero

This master thesis investigates the possibility of using a concrete recipe with only 70 % cement clinker for a building project named Gretas Glänta, regarding the demands of cracking for a suspended slab. The requirement to fulfill was a maximum crack width of 0.2 mm due to drying shrinkage and long- term loading. The purpose of using a lower amount of cement clinker in the concrete mix is to reduce the climate impact from the concrete. The thesis considers material testing and modelling of different concrete recipes with variation of the amount of cement clinker. Fly ash was used as the alternative binder. A total of five concrete mixes was tested. One mix with 100% cement clinker was through laboratory testing compared to mixes with 85 % and 70 % cement clinker content. A concrete mix with only 50 % cement clinker was also tested, but this mix is today not allowed according to the concrete standards, but was included in the study to test different material properties of the fresh and hardened concrete. All concrete mixes were tested with the effectivity factor 1, except for the recipe with 70 % cement clinker, which was tested for effectivity factors of 1 and 0.4. The performed study showed that the concrete mix 4 with 70 % cement clinker and with the effectivity factor 0.4 reached the strength class C35/45 after 28 days and also fulfilled the specified requirement of a maximum crack width of 0.2 mm due to drying shrinkage and long-term loading. Water permeability test showed that the concrete mix with 70 % cement clinker and an effectivity factor of 0.4 was waterproof. The concrete mix 3 with 70 % cement clinker and the effectivity factor 1 reached a strength class C30/37. The concrete mix 1 with 100 % cement clinker obtained the highest strength class C50/60 and the mix 2 with 85 % cement clinker reached strength class C45/55. The concrete mix 5 with 50 % cement clinker reached the strength class C20/25 which is the lowest strength class among the tested recipes. All the concrete recipes seemed to be waterproof according to the water permeability test. A background description of carbon dioxide emission from concrete and cement production is presented in the report. Research about ongoing methods to minimize the emission from concrete and cement industry is also summarized. FE-modelling with the software FEM-design and analytical calculations were performed to investigate the crack width due to drying shrinkage and long-term loading for the slab, for concrete mix 2 with 85 % cement clinker with effectivity factor 1 and mixes 3 and 4 with 70 % cement clinker and effectivity factors of 1 and 0.4. The properties obtained from the laboratory tests were used in the modelling and analytical calculations. Results from FEM-design and analytical calculations showed that concrete mixes 3 and 4 with 70 % cement clinker and effectivity factors of 1 and 0.4, and the concrete mix 2 with 85 % cement clinker with effectivity factor 1, fulfilled the demand on crack width. The calculation was not performed for concrete mixes 1 and 5 with 100 % and 50 % cement clinker, respectively, because they were not to be used in the building project. The results from the performed study showed that concrete mix 4 with 70 % cement clinker and an effectivity factor of 0.4 can be used in the building project Gretas Glänta in order to lower the climate impact from the concrete. / Examensarbetet undersöker möjligheten att använda ett betongrecept med endast 70 % cementklinker för ett husbyggnadsprojekt kallat Gretas Glänta med hänsyn till krav på sprickbildning i en fribärande platta. Kravet som ska uppfyllas är en sprickvidd på max 0.2 mm med hänsyn till krympning och långtidsbelastning. Syftet med att använda en lägre andel cementklinker i betongblandningen är att minska klimatpåverkan från betongen. Examensarbetet består av materialförsök och konstruktionsteknisk modellering för olika betongrecept, där andelen cementklinker varieras. Flygaska användes som alternativt bindemedel. Totalt undersöktes fem betongmixer. En mix med 100 % cementklinker jämfördes genom laboratorietestning med motsvarigheter med 85 % och 70 % cementklinkerinnehåll. Ett betongrecept med 50 % cementklinker undersöktes också i detta examensarbete, trots att detta idag inte tillåts enligt betongstandarderna, men inkluderades i studien för att testa olika materialegenskaper i färskt och hårdnat tillstånd. Alla betongmixerna testades med effektivitetsfaktorn 1 förutom receptet med 70 % cementklinkerandel som testades för både 1 och 0.4 i effektivitetsfaktor. Den genomförda studien visade att betongmix 4 med 70 % cementklinker och med effektiviseringsfaktor 0.4 uppnådde hållfasthetsklass C35/45 efter 28 dagar och uppfyllde också angivet krav på maximal sprickbredd 0,2 mm med hänsyn till krympning och långtidslast. Vattenpermeabilitetstest visade att betongmixen med 70 % cementklinker och effektiviseringsfaktor 0.4 var vattentätt. Betongmix 3 med 70 % cementklinker och effektivitetsfaktor 1 uppnådde hållfasthetsklass C30/37. Betongmix 1 med 100 % cementklinker erhöll den högsta hållfasthetsklassen C50/60 och betongmix 2 med 85 % cementklinker gav hållfasthetsklass C45/55. Betongmix 5 med 50 % cementklinker uppnådde hållfasthetsklass C20/25 vilket var den lägsta av de testade betongrecepten. Alla betongrecepten verkade ge vattentät betong enligt vattenpermeabilitetstest. En bakgrundsbeskrivning av koldioxidutsläpp från betong- och cementproduktion genomförs i rapporten. Forskning om pågående metoder för att minimera utsläppen från betong- och cementindustrin sammanfattas också. FE-modellering med programmet FEM-design och analytiska beräkningar utfördes för att undersöka sprickbredden med hänsyn till krympning och långtidslast för betongplattan för betongmix 2 med 85 % cementklinker och effektiviseringsfaktor 1 och betongmixerna 3 och 4 med 70 % cementklinker och effektiviseringsfaktorerna 1 och 0.4. Egenskaperna som erhölls i laboratorietesterna användes i modellerings och de analytiska beräkningarna. Resultat från FEM-design och analytiska beräkningarna visade att betongmixerna 3 och 4 med 70 % cementklinker med effektiviseringsfaktorerna 1 och 0.4 och betongmix 2 med 85 % cementklinker och effektiviseringsfaktor 1 uppfyllde kravet på sprickbredd. Beräkningen utfördes inte för betongmixerna 1 och 5 med 100 % cementklinker och 50 % cementklinker då de inte var aktuella för att användas i bostadsprojektet. Resultaten från den genomförda studien visade att betongmix 4 med 70% cementklinker och med en effektivitetsfaktor 0.4 kan användas i husbyggnadsprojektet Gretas Glänta för att sänka klimatpåverkan från betongen.