[report] Kemian tekniikan korkeakoulu / CHEM
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Item Sulfide Mineralogy - Literature Review(Aalto University, 2010) Tesfaye, Fiseha; Taskinen, Pekka; Materiaalitekniikan laitos; Department of Materials Science and Engineering; Metallurgical Thermodynamics and Modeling Research Group; Metallurgisten prosessien termodynamiikka ja mallinnus; Kemian tekniikan korkeakoulu; School of Chemical TechnologyThe aim of this study was to have an insight into the sulfide mineralogy, mainly based on sulfides mineralogical studies prior to the year 1975. In the first two chapters, the metal sulfides crystal structures and chemistries are reviewed. Then, the electronic interactions and chemical bonding followed by experimental methods in sulfides research with the proposed phase equilibria are reviewed. Phase relations in the (Cu, Ni, Zn)-S systems are discussed. Due to its influential and common appearance, in most natural sulfides (the common rock-forming minerals: po and py), the Fe-S system has been summarized relatively in detail. Sulfide petrology has been also discussed. The metal sulfides are the raw materials for most of the world supplies of non-ferrous metals. Their complex chemistry, as a result of high impurities association (such as As, Sb, Bi, etc...) and less base-metals content (metal poor rocks: composition of base-metal is less than 1 at.%), and the ever growing demand for the metals as well as the embroiling need to optimize minerals processing and sulfides smelting claim intense mineralogical studies. The main goal of such studies are to acquire accurate thermodynamic data which are useful to predict reactions and stable relationships, and in defining the limiting conditions under which phases may exist.Item Densities of Molten and Solid Alloys of (Fe, Cu, Ni, Co)-S at Elevated Temperatures - Literature Review and Analysis(Aalto University Publications in Materials Science and Engineering, 2010) Tesfaye, Fiseha; Taskinen, Pekka; Materiaalitekniikan laitos; Department of Materials Science and Engineering; Metallurgical Thermodynamics and Modelling Research Group; Metallurgisten prosessien termodynamiikan ja mallinnuksen tutkimusryhmä; Kemian tekniikan korkeakoulu; School of Chemical TechnologyDensities of solid and liquid Fe, Cu, Ni and Co, and their alloys both at the presence and absence of sulfur have been reviewed. Volumetric thermal expansions were used to estimate the densities at different temperatures. Densities of the alloys generally decrease with increasing temperature. For the pure metals the reduction in density as temperature rises from 25 oC to their respective melting point can be estimated to be about 7.05 ± 0.4 % just before melting and about 11.63 ± 0.92 on complete melting. According to the literature data and the analyzed results, at ambient pressure condition, density of the stoichiometric FeS changes from 4.615 g/cm3 at 25 oC to 3.8 g/cm3 at 1200 oC (17.7 %), density of the stoichiometric Cu2S changes from 5.65 g/cm3 at 25 oC to 5.18 g/cm3 at 1200 oC (8.3 %), density of the stoichiometric NiS changes from 5.5 g/cm3 at 25 oC to 5.025 g/cm3 at 1027 oC (8.5 ± 1.8 %) and density of the stoichiometric CoS changes from 5.45 g/cm3 at 25 oC to 4.88 g/cm3 at 1100 oC (10.45 %). A study on the Fe-S melts at 4GPa suggests that in sulfur-poor compositions, where solubility of sulfur is less likely to be affected by pressure, the density of the sulfides at isothermal conditions decreases in a similar fashion as under 1 bar, i.e., density decreases non-linearly with increasing composition of sulfur.Item Thernmodynamics and Phase Equilibria in the (Ni, Cu, Zn)-(As, Sb, Bi)-S Systems at Elevated Temperature (300-900 C)(Aalto University, 2010) Tesfaye, Fiseha; Taskinen, Pekka; Materiaalitekniikan laitos; Department of Materials Science and Engineering; Metallurgical Thermodynamics and Modeling Research Group; Metallurgisten prosessien termodynamiikka ja mallinnus; Kemian tekniikan korkeakoulu; School of Chemical TechnologyStable phase relations in the (Ni, Cu)-(As, Sb)-S, Cu-Bi-S and Zn-As-S systems and their thermodynamic properties, at the presence of the impurities, are reviewed. The Cu-based systems are relatively intensively studied. Among the sulfosalts of these systems tetrahedrite (Cu12+xSb4+yS13, where 0 < x < 1.92 and -0.02 < y < 0.27) and tennantite (Cu12+xAs4+yS13, where 0 < x < 1.72 and 0 < y < 0.08) are reported to be the most stable relative to other sulfosalts and certain other sulfide phases, which accounts for their common occurrence in a variety of mineral ore deposits. Natural tetrahedrite and tennantite in equilibrium with other minerals commonly constitute other chemical elements as a substitution for Cu, As and Sb and both are described by the general formula:(Cu, Ag)10(Fe, Zn, Cu, Hg, Cd, Co, Au)2(Sb, As)4S13. According to the literature data the Ni-based systems comprise a single stoichiometric ternary stable phase for their respective impurities (gersdorffite, NiAsS, and ullmannite, NiSbS), and both experience a wide solid solubility range. At favorable conditions substitution of As for S in the gersdorffite and Co for Ni and Sb for As in the ullmennite are the main mechanisms of solid solution formations. Thermodynamic properties and phase equilibria studies in the Zn-As-S system are rare among published litrature. A study about this system, below 760 oC, has shown that there is no ternary phase stable. In general, the ternary systems have complex phase relations, which may be as a result of the very low differences in their Gibbs energies of formation.Item Päätösmetodit hydrometallurgisen yksikköprosessin valinnassa(Aalto-yliopisto, 2011) Rintala, Lotta; Lillkung, Kristian; Materiaalitekniikan laitos; Kemian tekniikan korkeakouluItem Phase equilibria and thermodynamics of the system Zn-As-Cu-Pb-S at temperatures below 1173 K(Aalto University, 2011) Tesfaye, Fiseha; Taskinen, Pekka; Materiaalitekniikan laitos; Kemian tekniikan korkeakouluItem ACTIVITY REPORT 2007 - 2010(Aalto University, 2011) Jämsä-Jounela, S.-L.; Kämpe, J.; Räisänen, A.; Biotekniikan ja kemian tekniikan laitos; Department of Biotechnology and Chemical Technology; Kemian tekniikan korkeakoulu; School of Chemical TechnologyAalto University School of Science and Technology is the largest and oldest institute of engineering education in Finland. The University campus is situated about 10 km west of Helsinki in the Otaniemi area, in the township of Espoo. The number of undergraduates is about 12 000 and that of postgraduates about 2800. The degrees offered in the School of Science and Technology are the basic Master’s degree in engineering, architecture or landscape-architecture (minimum 4.5 years) and the postgraduate degree Doctor of Technology (minimum 4 years). The Department of Biotechnology and Chemical Technology comprises eight research groups (= eight full professorships): Biochemistry, Microbiology, Bioprocess Technology, Chemical Engineering, Plant Design, Industrial Chemistry, Polymer Technology and Process Control. The Laboratory of Process Control and Automation, as a member of the department was founded in 1987. The aim of the laboratory is to serve all fields of process technology - chemical, metallurgical and forest products - in terms of process automation. The laboratory gives courses in process modelling, simulation, control, optimization and automation as well as in production control. The undergraduate students typically have a few years background of process engineering studies, after which a one-to-two-year portion of automation studies. Post-graduate students typically work in the field of process technology - either in the industry or in research institutes or universities - while studying. This report describes briefly the staff, teaching, facilities, research and other activities of the Laboratory of Process Control and Automation during 2007 - 2010.Item Teräskennorakenteiden korroosio merivedessä(Aalto University, 2011) Aromaa, Jari; Leino, Jaakko; Pehkonen, Antero; Virtanen, Jorma; Materiaalitekniikan laitos; Department of Materials Science and Engineering; Kemian tekniikan korkeakoulu; School of Chemical TechnologyItem MT-0.3201 : materials production and synthesis / 2011(Aalto University, 2011) Kekkonen, Marko (editor); Materiaalitekniikan laitos; Department of Materials Science and Engineering; Kemian tekniikan korkeakoulu; School of Chemical TechnologyItem Hydrometallurgical recovery of platinum group metals(Aalto University, 2012) Lillkung, Kristian; Aromaa, Jari; Materiaalitekniikan laitos; Department of Materials Science and Engineering; Corrosion and Hydrometallurgy; Korroosio ja hydrometallurgia; Kemian tekniikan korkeakoulu; School of Chemical TechnologyThe demand for platinum group metals (PGMs) has been rising significantly for the last few decades as the metals have become very important for the today’s society. They are used in pollution control and also in many other applications where their unique properties are needed. It seems that the trend is towards even further increase in the consumption due to tightening emission standards and new energy sources. The supply of PGMs is limited as they only exist in a larger scale in South Africa and Russia. As the end products where PGMs are used are scattered around the globe, the recycling of the metals at these locations also seems attractive. This literature review focuses on the extraction and separation processes used in the platinum group metals industry nowadays. The information available is partly limited as companies are not willing to give their secrets away. Most of the processes reviewed are meant for primary metals processing, but some of them are also used to recycle PGMs from secondary sources. The number of specific processes proposed in the literature is high, but most of these processes are however mainly modifications from existing processes and based on the same principles. Differences in the used raw material lead to clear differences in the used process chemistry and technology when producing platinum group metals. As more metals are present, usually a more complex process chain has to be utilized. The process chemistry has to adapt easily to small changes in order to make the process profitable. In this report some of the commercially available processes were reviewed as well as some of the processes proposed in the literature. No one outstanding process stood out, but many processes have advantages that can be employed when processing some certain ore or secondary material. The modern process technology employing ion exchange and molecular recognition appears to be more flexible considering the raw material. This has been one of the reasons besides faster and more efficient operation, why the traditional processing methods have been replaced by the modern refining processes.Item Alkaline leaching of iron and steelmaking dust(Aalto University, 2012) Stafanova, Anna; Aromaa, Jari; Materiaalitekniikan laitos; Department of Materials Science and Engineering; Kemian tekniikan korkeakoulu; School of Chemical TechnologySteel production generates significant quantities of dust and sludge in blast furnaces (BF),basic oxygen furnaces (BOF), and electric arc furnaces (EAF). These dusts contain toxicelements, such as heavy metals, and are thus classified as harmful waste making the disposalof them expensive. In addition, direct recycling of dust back to steel production is hindered dueto the presence of zinc. In this literature survey the alkaline leaching of zinc from iron and steelmaking dusts isreviewed. The characteristics of EAF, BOF and BF dust and their processing based on causticsoda (NaOH) leaching is described. Also some methods, e.g. pre-treatments, to enhanceleaching are introduced. Dusts from iron and steel production consist mainly of ferrous oxides. In addition, theycontain zinc, lead and cadmium oxides as well as minor amount of many other elements. Thezinc content in EAF dust can run up 30 %, when it is usually lower in BOF and BF dusts, around1-3 % and 1.5 %, respectively. Zinc is present mainly as zinc oxide, ZnO (50-80 %), and rest is aszinc ferrite, ZnFe2O4. The dusts are very fine (usually < 0.01 mm) and have tendency to agglomerate. Metal extraction from the dusts is difficult due to their complex composition and finding asuitable process is complicated as each dust is unique. The advantage of caustic soda leachingis its selectiveness in leaching zinc compared to iron compounds. Thus a relatively clean andiron-free solution is obtained and the complicated iron removal processes is avoided. Somefacilities using NaOH leaching have been constructed for dissolving zinc from the steelmakingdusts, but they have been closed as inefficient and expensive. For the optimal leaching conditions 6-10 M NaOH solution, liquid to solid ratio of around 10,and temperature of 80 – 95 °C has been presented. Zinc recoveries of 80-85 % can be reachedbut part of zinc is not dissolved and recovered. ZnO dissolves easily in caustic soda, butZnFe2O4 is highly stable compound and is the major obstruction in the hydrometallurgicalextraction of zinc. Pressure leaching, and microwave or ultrasound assisted leaching has notimproved significantly zinc recovery. For breaking the zinc ferrite structure, pyrometallurgicalprocesses, such as roasting, can be used prior to leaching. By roasting with caustic soda priorto alkaline leaching zinc ferrites can be decomposed and leaching of zinc could be improved.Item Phase equilibria and thermochemistry of selected sulfide systems in the pyrometallurgy of Ni and Cu(Aalto University, 2012) Tesfaye, Fiseha; Taskinen, Pekka; Materiaalitekniikan laitos; Department of Materials Science and Engineering; Kemian tekniikan korkeakoulu; School of Chemical TechnologyA review of phase equilibria and thermodynamic data of Ni-(As, Se)-S and Cu-(As, Bi, Pb, Sb,Se, Te, Nb, Zn, Mo)-S systems was done. Particular emphases were given to the compilationand refine of the standard Gibbs energies of formations of equilibrium phases, which are ofinterest in the pyrometallurgical processes of copper and nickel production. Phase stabilities,phase relations and solubility limits of some equilibrium phases in the Ni-(As, Se)-S and Cu-Mo-Bi-Nb-S systems were also compiled and reviewed, based on the available literature.This work also reviews, updates, and extends the earlier reports. The Gibbs energies offormations and reactions are mostly presented as linear equations, in each temperature rangesof phase stabilities. List of thermal stabilities of some pure sulfides and sulfosalts were alsoreviewed and compiled (Appendix).Item Properties of the liquid miscibility gap in the system Cu-Cu2S(Aalto University, 2012) Forsström, Antti; Taskinen, Pekka; Johto, Hannu; Materiaalitekniikan laitos; Department of Materials Science and Engineering; Kemian tekniikan korkeakoulu; School of Chemical TechnologyItem Lectures in English as a Lingua Franca - Interactional Features(Aalto University, 2012) Suviniitty, Jaana; Puunjalostustekniikan laitos; Department of Forest Products Technology; Kemian tekniikan korkeakoulu; School of Chemical TechnologyInternationalization is one of the strategic goals of universities and other higher education institutions in Finland. This tends to be transferred to English-medium instruction (EMI) and English degree programs. This "Anglicization” has raised concerns and discussion despite its perceived benefits. The aim of this study was to investigate an international Master’s Program in the field of engineering and to explore students’ perceptions of lectures and their comprehension within this Master’s Program. These lectures were further examined in order to shed light on what linguistic features used in English as a lingua franca (ELF) lecturing influence students’ perceptions. This exploratory, descriptive case study takes a phasal approach to obtain a holistic view on this Master’s Program. The findings of the study are based on authentic data: video-recorded lecture material, their transcriptions, and surveys. These surveys contain lecture evaluations provided by the students immediately after attending them. Guided by the student evaluations, an analysis based on genre analysis and discourse analysis was conducted to locate the linguistic differences of these lectures. The results indicate that students’ perception of lectures relates to the use of interactionalfeatures regardless of the lecturers’ perceived English skills. Those lectures students found accessible contained more interactional features than those lectures students found challenging. Additional results, contrary to prior studies, also show that the use of interactional features in native language (Finnish) lecturing is notably lower than in ELF lecturing. Furthermore, the comparison of student achievements when lecturing in the Master’s Program was in Finnish with the student achievements from the ELF lectured program showed slightly higher results in the ELF lectured program. Conclusions drawn from these results suggest that when lecturing in a non-native language, lecturers attempt to ensure the audience’s comprehension through various linguistic devices, interactional features being one of them. Therefore, ELF lectures do not have an adverse effect on lecture comprehension or course results.Item Viscosity models for molten slags(Aalto University, 2012) Kekkonen, Marko; Oghbasilasie, Haile; Louhenkilpi, Seppo; Materiaalitekniikan laitos; Department of Materials Science and Engineering; Kemian tekniikan korkeakoulu; School of Chemical TechnologyThe understanding and optimisation of the metallurgical processes require access to accurate data of the physical properties of slags. Viscosity is one of the most important properties in the case of metallurgical melts, in view of its direct effect on the kinetic conditions of the processes, and is one of the key factors to be taken into consideration in process modeling. The difficulty and high cost of measuring the viscosity of slags has led to development of number of viscosity models. Most of these models employ parameters extracted from experimental data of viscosity, which ensure the validity of the models in viscosity estimation. In this report models developed to estimate the viscosity of fully molten oxide slags were discussed. In addition viscosities of converter slags (Basic Oxygen Furnace, Argon-Oxygen Decarburization furnace) predicted with different models were compered. In the case of BOF-slag the Iida and the modified Urbain models seemed to be more reliable than the other models in predicting the viscosities. The values calculated by KTH model were too high for this high basic slag whereas in the case of NPL model the slag composition was observed to be outside of the working range of the model. Urbain model modified by Forsbacka as well as the modified Iida models takes account of chromium oxide as a separate component in the calculations and are thus assumed to be more reliable than the other models in predicting viscosities of chromium containing slags. However the reliability of these models is debatable in the case of high chromium containing slags e.g. AOD-slag after oxidising period due to existing of solid phases in the slag. Iida as well as the Urbain model modified by Forsbacka are also assumed to be reliable predicting viscosity of slag composition corresponding the AOD-slag after reduction period. Also NPL-model seemed to give reliable viscosity values, since in this case the slag composition is inside the working range of the model. Although there are plenty of experimentally measured viscosity data available for ternary systems, less data in limited ranges are available as the order of the system gets higher. Also lack of experimental data of very basic slag compositions as well as slags containing iron and chromium oxides is apparent. Due to lack of experimental data the performance of these models in predicting viscosities of converter slags was not able to evaluate. Thus more experimental work is necessary to provide the data to test and optimise the models for these very complex slag compositions.Item Yrittäjyys maahanmuuttajien integroitumisen keinona Pohjanmaalla(Aalto University, 2012) Melin, Kirsti; Melin, Kristian; Biotekniikan ja kemian tekniikan laitos; Department of Biotechnology and Chemical Technology; Tehdassuunnittelun tutkimusryhmä; Kemian tekniikan korkeakoulu; School of Chemical TechnologyThe entrepreneurial activity in Finland is higher among immigrants than among Finnish people. Immigrants think more frequently than native people that entrepreneurship is a channel to social and economic independence and appreciation. For a part of the immigrant entrepreneurship is the best way to get a good income in their new homeland and in a foreign culture. Reasons for interest in entrepreneurship can be many. Already immigration to another country tells about the activity and ability to take a risk of the person. These are also qualities needed for entrepreneurship. Many of the ethnic entrepreneurs also come from cultures where entrepreneurship is very common and the attitudes toward entrepreneurship are positive. Many immigrants can also get a job quickest by self-employment. Some people who cannot get any job otherwise. That is called forced entrepreneurship. The younger age among immigrants also favor entrepreneurship. This research consists of two parts. The first part creates based on statistics a profile of immigrant entrepreneurs in Pohjanmaa. The Statistical are mainly based on the data from National Board of Patents and Registration of Finland at the end of 2011. In the other part of this research we are seeking answer to the question: To what extent the entrepreneurship integrates immigrants to the Finnish society. In this part 30 immigrant entrepreneurs in Pohjanmaa have been interviewed. There are 20 different nationalities in 11 different municipalities in Pohjanmaa. The data has been analyzed using analysis of content. According the statistical data there were 418 companies of the immigrants in Pohjanmaa in 2011. The number of entrepreneurs was 520 and of them 27 % were women. The greatest business areas were trade, hotel and restaurant business, construction business and welfare services. Most of the companies have been established after 2006. Among the interviewed 22 persons thought that entrepreneurship had integrated them to the Finnish society. On the opposite 6 respondents saw that entrepreneurship had not integrated them to Finnish society and two respondents could not say anything about the matter. Factors that favored integration of entrepreneurs to Finnish society were networking, good education and professional skills of the immigrants. In addition the help of foundation, advice and finance of Finnish society, positive attitude and confidence of the Finnish people.Item Materials production and synthesis/ 2013 : MT-0.3201(Aalto University, 2013) Kekkonen, Marko (ed.); Materiaalitekniikan laitos; Department of Materials Science and Engineering; Kemian tekniikan korkeakoulu; School of Chemical TechnologyItem Teollisuuden ympäristöasioiden hallinta(Aalto University, 2013) Laukkanen, Timo; Dahl, Olli Martikka, Mikko; Puunjalostustekniikan laitos; Department of Forest Products Technology; Kemian tekniikan korkeakoulu; School of Chemical TechnologyItem European Forest Products Doctoral Symposium 2013(Aalto University, 2013) Järvelä, Heli (graphic design); Puunjalostustekniikan laitos; Department of Forest Products Technology; Kemian tekniikan korkeakoulu; School of Chemical TechnologyItem Korroosion ja korroosioneston historia(Aalto University, 2013) Aromaa, Jari; Materiaalitekniikan laitos; Department of Materials Science and Engineering; Korroosio ja hydrometallurgia; Kemian tekniikan korkeakoulu; School of Chemical TechnologyKorroosio on teknologian alue, joka käsittelee materiaaleja, ympäristöjä ja niiden vuorovaikutusta, ja jonka painotus on teknisten ratkaisujen toiminnan varmistamisessa. Korroosio alkoi aiheuttaa ongelmia teknisissä ratkaisuissa jo 1400-1600-luvuilla. Korroosion vaarallisia vaikutuksia ei havaittu, ennen kuin metalleja alettiin käyttää runsaasti rakenteisiin, koneisiin ja laitteisiin. Korroosion yleistyminen ja korroosionestomenetelmien kehittämisen alku ajoittuvat 1850-luvulle. Jo 1900-luvun alussa oltiin huolestuneita rautamalmien riittävyydestä, koska yhä suurempi osa teräsrakenteista tuhoutui korroosion takia. Yhdysvalloissa vuosina 1999-2001 tehdyn arvion mukaan suorat korroosiokustannukset olivat 3,2 % bruttokansantuotteesta ja epäsuorat ainakin yhtä suuret. Vakavia onnettomuuksia, joissa korroosio on ollut merkittävä tekijä, on ollut useita. Tämä kirjallisuustutkimus on katsaus poikkitieteellisen tekniikan alan teorian ja ajattelutapojen kehittymisestä nykytilaansa.Item MT-0.3201 : Materials production and synthesis / 2014(Aalto University, 2014) Kekkonen, Marko (ed.); Materiaalitekniikan laitos; Department of Materials Science and Engineering; Kemian tekniikan korkeakoulu; School of Chemical Technology