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  • 1.
    Alm, Ove
    Luleå tekniska universitet.
    Mechanical testing of powders and powder compacts1983In: Scandinavian journal of metallurgy, ISSN 0371-0459, E-ISSN 1600-0692, Vol. 12, no 6, p. 302-311Article in journal (Refereed)
    Abstract [en]

    Results from standard triaxial, uniaxial and bending tests are presented. Triaxial tests were performed at pressures in the range 0-200 MPa. Both initial loose powder samples and cylindrical precompacted specimens were studied under hydrostatic conditions. Most of the total volume compaction occurred at pressures below 10 MPa. Triaxial tests with superimposed axial loads showed no softening despite a 30% shortening of the length of specimens which initially were 60 mm long. Specimens deformed in triaxial tests showed a higher density and a higher uniaxial compressive strength than specimens compacted under hydrostatic conditions

  • 2.
    Andersson, G.
    Luleå tekniska universitet.
    Creep experiments on powder1983In: Scandinavian journal of metallurgy, ISSN 0371-0459, E-ISSN 1600-0692, Vol. 12, no 6, p. 312-314Article in journal (Refereed)
    Abstract [en]

    The change in strain during constant loading in die, isostatic and triaxial compaction has been studied for tungsten carbide powder. The creep effect change is largest for isostatic loose powder compaction whereas the slightly precompacted specimens (20 MPa) show less strain change. The creep effect gives modest contributions to the total strain for reasonable times. The highest pressure at which the effect has been recorded is 200 MPa

  • 3.
    Banda, S.M.Herath
    et al.
    Luleå University of Technology.
    Forssberg, Eric
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Pressure filtration of a fine-grained chalcopyrite concentrate1988In: Scandinavian journal of metallurgy, ISSN 0371-0459, E-ISSN 1600-0692, Vol. 17, no 2, p. 61-66Article in journal (Refereed)
    Abstract [en]

    How material properties, cake characteristics and operating parameters affect the filtration rate and the final moisture content was investigated by laboratory test with a concentrate from a complex sulfide ore. Porosity and pore size distribution were measured by automatic image analysis. With optimum conditions, a moisture content of 5. 5% was achieved. A copper/lead concentrate floated from a complex sulfide ore at the Stekenjokk concentrator of Boliden Mineral AB, Sweden was used.

  • 4.
    Banda, S.M.Herath
    et al.
    Luleå University of Technology.
    Forssberg, Eric
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Structure variation in filter cakes from flocculated slurries1988In: Scandinavian journal of metallurgy, ISSN 0371-0459, E-ISSN 1600-0692, Vol. 17, no 2, p. 57-60Article in journal (Refereed)
    Abstract [en]

    To flocculate slimy material dispersed in water is a common operation in mineral processing either to recover the material or to clear the water. In laboratory tests with flocculated slurries, floc sizes, porosity and sizes of filter cakes were measured by automatic image analysis. An observed decrease in filtrate flow rate at flocculant overdosage was not caused by a smaller mean floc size but may have been due to an obstruction of the pore channels by adsorbed polymer threads. Samples of a copper/lead concentrate floated at the Stekenjokk concentrator of Boliden Mineral AB, Sweden, were used for this investigation.

  • 5.
    Banda, S.M.Herath
    et al.
    Luleå University of Technology.
    Forssberg, Eric
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Variation of filter cake permeability with mean pore diameter of the cake1998In: Scandinavian journal of metallurgy, ISSN 0371-0459, E-ISSN 1600-0692, Vol. 17, no 2, p. 67-72Article in journal (Refereed)
    Abstract [en]

    It is shown that most particles in a filter cake have more than only point contact with each other. Therefore, the Kozeny-Carmen equation is modified by relating permeability to porosity and a mean pore diameter as measured by automatic image analysis in horizontal cross sections of the cake. In filter cakes of chalcopyrite and magnetite, the permeability increases stepwise with the product of porosity and square mean pore diameter.

  • 6.
    Bengtsson, B.
    et al.
    Luleå tekniska universitet.
    Easterling, K.E.
    Luleå tekniska universitet.
    Quantitative STEM microanalysis1978In: Scandinavian journal of metallurgy, ISSN 0371-0459, E-ISSN 1600-0692, Vol. 7, no 2, p. 57-59Article in journal (Refereed)
  • 7.
    Björkman, Bo
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Holmström, Åke
    Luleå tekniska universitet.
    A Quantitative Comparison of the Impurity Capacity in Some Copper Making Routes1989In: Scandinavian journal of metallurgy, ISSN 0371-0459, E-ISSN 1600-0692, Vol. 18, no 1, p. 2-11Article in journal (Refereed)
    Abstract [en]

    A metallurgical comparison of alternatives to increase the capacity to treat contaminated raw materials was made. The comparison was made by calculating the material balances at different Cu contents in mattes during Cu making and considering the effects of removal of impure intermediate products like dusts and slag for separate treatment. The most efficient methods included the removal of dust from the smelting furnace and the avoidance of reducing conditions in the matte smelting operation. By separating dust and slag produced in the Cu converters, an improved capacity could also be obtained. The removal of impurities made it possible to significantly increase the use of contaminated raw materials but, to drastically increase the impurity capacity, the introduction of pretreatment processes like roasting or leaching was necessary

  • 8.
    Bolin, Nils Johan
    Luleå tekniska universitet.
    Study of muscovite flotation from a pegmatite ore1983In: Scandinavian journal of metallurgy, ISSN 0371-0459, E-ISSN 1600-0692, Vol. 12, no 3, p. 117-120Article in journal (Refereed)
    Abstract [en]

    The article shows the relationship between the iron ion content of the flotation pulp and the selectivity of mica flotation of a granitic pegmatite from Limbergsbo, Sweden which contains 40% albite, 20% microcline, 30-35% quartz and 4% muscovite. The results of comparative experiments involving flotation in stainless steel and iron-rich environments show that selectivity with respect to microcline and quartz is better when an iron mill is used for grinding

  • 9. Brämming, Mats
    A blast furnace view on slags2002In: Scandinavian journal of metallurgy, ISSN 0371-0459, E-ISSN 1600-0692, Vol. 31, no 2, p. 88-99Article in journal (Refereed)
    Abstract [en]

    In 1982, SSAB, Luleå Works, converted the blast furnace ferrous burden from an acid to an olivine pellet with a high Fe content. This change made it possible to gradually reduce the slag volume to 150 kg per metric ton of hot metal with huge positive effects on the blast furnace operation. SSAB, Oxelösund Works, can present a similar development, initially by increasing the Fe content in sinter and later by converting to a 100% olivine pellet operation in 1995. In addition to a description of the historical development of the properties of SSAB blast furnace slags, this paper describes the technical means and issues as well as the environmental constraints governing future developments of slag volume and chemistry, including effects of changes in burden quality and possible tuyere injection of slag formers.

  • 10.
    Easterling, K.E.
    Luleå tekniska universitet.
    Scanning-transmission electron-microscopy and microanalysis1977In: Scandinavian journal of metallurgy, ISSN 0371-0459, E-ISSN 1600-0692, Vol. 6, no 1, p. 3-5Article in journal (Refereed)
  • 11.
    Forssberg, Eric
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Bolin, Nils Johan
    Luleå University of Technology.
    Phosphate bonded fused alumina abrasive resistant material1980In: Scandinavian journal of metallurgy, ISSN 0371-0459, E-ISSN 1600-0692, Vol. 9, no 5, p. 211-215Article in journal (Refereed)
    Abstract [en]

    Suitable particle size distribution and proportion of binder phase have been determined by measurements of mechanical strength and abrasion tests. A pump impeller was made. Comparative abrasion tests have shown that the abrasion resistance is better than that of a cast iron impeller and comparable to that of a rubber impeller.

  • 12.
    Forssberg, Eric
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Jonsson, H.
    Adsorption of heavy metal ions on pyrrhotite1981In: Scandinavian journal of metallurgy, ISSN 0371-0459, E-ISSN 1600-0692, Vol. 10, no 5, p. 225-230Article in journal (Refereed)
    Abstract [en]

    Relatively large amounts of heay metal ions can be adsorbed on synthetic and natural pyrrhotite. The best result was obtained with Cu ions and pyrrhotite from Viscaria, with an adsorption of 4. 95 g Cu per kilogram of pyrrhotite. Good results have also been obtained with zinc and lead ions. A strongly oxidizing environment can have an adverse effect

  • 13.
    Forssberg, Eric
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Sivamohan, Rajaratnam
    Luleå University of Technology.
    Dynamic flow characteristics of thin films1985In: Scandinavian journal of metallurgy, ISSN 0371-0459, E-ISSN 1600-0692, Vol. 14, no 4, p. 163-174Article in journal (Refereed)
    Abstract [en]

    Viscosity is generally cited as a chief cause for any decrease in efficiency noticed in concentration processes, particularly with undeslimed feeds, despite the fact that there is little conclusive information available on the importance of viscosity. The literature on viscosity as applied to gravity processes is critically reviewed. The dynamic flow characteristics of natural slimes containing a large amount of ultra-fine particles-exclusively clay is studied at different slime concentrations and pH. Except for some tendency to gel at low pH with low rates of shear, they behave almost as Newtonian fluids with extremely low apparant viscosities even with about 55 %-5 mu m clayey matter. At intermediate concentrations suspensions show strong gelling behavior and pH effects become pronounced. At rates of shear on concentrating equipment, pH influence becomes less significant and apparent viscosity drops greatly. A mathematical analysis of dynamic flow characteristics of thin films is made as a function of distance from the surface of the deck. The viscosity effect due to ultra-fine particles is negligible under conditions prevailing in slime gravity processes.

  • 14. Forssberg, Eric
    et al.
    Sköld, Börje
    Luleå University of Technology.
    Method for determining the attraction forces on magnetic separators1972In: Scandinavian journal of metallurgy, ISSN 0371-0459, E-ISSN 1600-0692, Vol. 1, no 6, p. 290-292Article in journal (Refereed)
    Abstract [en]

    The equipment here only measures the radial component of magnetic attraction. The radial component is also of interest in separations where centrifugal force and the force of gravity are to be balanced against the magnetic attraction, i. e. dry top-feed separators for both coarse and fine material. In the case of wet separators, the radial component has the greatest influence on attraction to the drum surface of magnetic particles and on the ability of the magnet assembly to retain the magnetic material on the surface.

  • 15.
    Forssberg, Eric
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Zhai, Hongxin
    Luleå University of Technology.
    3D behaviour of the parameters affecting grinding in a batch ball mill1986In: Scandinavian journal of metallurgy, ISSN 0371-0459, E-ISSN 1600-0692, Vol. 15, no 1, p. 53-58Article in journal (Refereed)
    Abstract [en]

    To obtain an extensive understanding of the behavior of the key parameters in grinding processes, factorial design is applied to a ball mill test using four variables, each at three levels. This required a total of 27 tests. The influence of charge volume, mill speed, feed and pulp density on grinding fineness and net energy consumption were related and in order by multiple regression analysis. The computer-based response surfaces of the dependent variables demonstrated the combined effects of the operational parameters. They also provided a base for further tests on the multiple influence of the process variables on continuous grinding.

  • 16.
    Forssberg, Eric
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Zhai, Hongxin
    Luleå University of Technology.
    Liberation modelling of base metal ores in autogenous grinding1985In: Scandinavian journal of metallurgy, ISSN 0371-0459, E-ISSN 1600-0692, Vol. 14, no 1, p. 9-17Article in journal (Refereed)
    Abstract [en]

    According to a mathematical model, each mineral has its own liberation-energy characteristic curve which can be plotted. The relations between liberation, mill speed and charge volume are also presented.

  • 17.
    Forssberg, Eric
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Zhai, Hongxin
    Luleå University of Technology.
    Quantitative model for the residence time distribution and its application in studying the Malmerget plant grinding system1986In: Scandinavian journal of metallurgy, ISSN 0371-0459, E-ISSN 1600-0692, Vol. 15, no 1, p. 41-48Article in journal (Refereed)
    Abstract [en]

    A quantitative model for the residence time distribution (RTD) in tumbling mills is derived. This model has a relatively simple form described in terms of only three characteristic parameters, which can be easily generated from multiple regression analysis by computer. The advantages of the model are very easy to understand and quite convenient to use for predicting the transport behavior of particles flowing through tumbling mills. More than 500 experimental data points obtained from industrial and pilot scales fit the model with sufficient accuracy.

  • 18.
    Forssberg, Eric
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Zhai, Hongxin
    Luleå University of Technology.
    Shape and liberation studies on grinding products from autogenous and conventional mill using an automatic image analyser1985In: Scandinavian journal of metallurgy, ISSN 0371-0459, E-ISSN 1600-0692, Vol. 14, no 6, p. 283-288Article in journal (Refereed)
    Abstract [en]

    Samples were collected from the Stekenjokk and Malmberget concentrators, operated by Boliden Mineral AB and Luossavaara-Kiirunavaara AB respectively. The Stekenjokk ore consists of massive pyrite with disseminated chalcopyrite and sphalerite; it assays 1. 4 % Cu and 3. 2 % Zn. The Malmberget ore mainly contains magnetite with a coarse-crystalline structure; run-of-mine ore assays are about 40 % Fe and 0. 6 % P. Using an automatic image analyzer, it appears that fully autogenous grinding down to flotation fineness results in better liberation and particle shape for flotation than is obtained with a combination of primary autogenous and ball mill grinding. Fully autogenous grinding also creates smoother particle surfaces.

  • 19.
    Forssberg, Eric
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Zhai, Hongxin
    Luleå University of Technology.
    Shape and surface properties of the particles liberated by autogenous grinding1985In: Scandinavian journal of metallurgy, ISSN 0371-0459, E-ISSN 1600-0692, Vol. 14, no 1, p. 25-32Article in journal (Refereed)
    Abstract [en]

    Autogenous grinding produces rounded particles with higher degrees of liberation and equiaxiality and lower roughness. These properties result in a higher grade concentrate and better recovery. Autogenous grinding is consequently more economical.

  • 20.
    Forssberg, Eric
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Zhai, Hongxin
    Luleå University of Technology.
    Nordqvist, Tommy
    Luleå University of Technology.
    Combined effects of processes variables on the residence time distribution of particles in an open-circuit ball mill1987In: Scandinavian journal of metallurgy, ISSN 0371-0459, E-ISSN 1600-0692, Vol. 16, no 1, p. 23-28Article in journal (Refereed)
    Abstract [en]

    A multiple parameter approach was used to determine the relative importance of the effects of charge volume, feed rate, mill speed and feed size on mean residence time. The implications of mean residence time for the particle size were also investigated.

  • 21. Gao, Mingwei
    et al.
    Forssberg, Eric
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Evaluation of the key grinding parameters by a statistical approach1989In: Scandinavian journal of metallurgy, ISSN 0371-0459, E-ISSN 1600-0692, Vol. 18, no 3, p. 113-121Article in journal (Refereed)
    Abstract [en]

    Four important grinding parameters, charge volume, feed rate, mill speed and the degree of classification, were studied. A continuous laboratory ball mill was used. The effects of these parameters on product size, energy consumption and grindability were analyzed by a statistical approach. The results obtained demonstrated that the energy consumption is determined not only by the given product size, but also to a great extent by the operating conditions. The influence of classification in a closed grinding circuit was also examined and it is shown that an efficient classification may improve the grinding process considerably. A sulfide ore containing sphalerite, chalcopyrite and galena was used.

  • 22. Grip, Carl-Erik
    et al.
    Johansson, Börje
    Swerea MEFOS AB.
    Bäcklund, Rolf
    Swerea MEFOS AB.
    Lindfors, Nils-Olof
    Swerea MEFOS AB.
    The development and use of high temperature models for the simulation of the Bosh in the blast furnace: Part I1976In: Scandinavian journal of metallurgy, ISSN 0371-0459, E-ISSN 1600-0692, Vol. 5, no 6, p. 239-276Article in journal (Refereed)
    Abstract [en]

    This report describes the development and use of a high temperature model for the simulation of the bosh in the blast furnace. As an illustration of the application of the model there follows a discussion on the influence of coke rate and coke size on the softening and permeability of a burden of pellets in the bosh, based on trials made with the model. The results indicate that the coke rate can have a critical influence on the pressure drop through the burden. With coke rates of 300 kg/ton hot metal (and less) an unacceptable pressure drop occurs. In addition the pressure drop, at a given temperature for a given coke rate, increases as the size of the coke decreases.

  • 23.
    Grip, Carl-Erik
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Jonsson, Kjell-Olov
    SSAB.
    Eriksson, Sven
    SSAB Oxelösund AB.
    Jonsson, Lage
    Swerea MEFOS AB.
    Jönsson, Pär
    Department of Metallurgy, Royal Institute of Technology, Stockholm.
    Pan, Yuhua
    Luleå tekniska universitet.
    Theoretical and practical study of thermal stratification and drainage in ladles of different geometry2000In: Scandinavian journal of metallurgy, ISSN 0371-0459, E-ISSN 1600-0692, Vol. 29, no 1, p. 30-38Article in journal (Refereed)
    Abstract [en]

    SSAB Luleå, SSAB Oxelösund, MEFOS and Luleå University of Technology have cooperated in developing theoretical models for prediction of thermal stratification and drainage in steel ladles. Predicted results have been verified by measurements done in production ladles with heat weighs of 105 and 200 tonne as well as in a 7-tonne pilot plant ladle. The thermal stratification was measured by thermocouples at different depths. The drainage flow was studied by means of tracer experiments. Numerical simulation models of the steel flow were developed for 7, 105 and 200 tonne steel ladles. The agreement between predictions and measurements was found to be good. The conclusion is that CFD simulation gives a good prediction of stratification and drainage flows in production ladles.

  • 24.
    Grip, Carl-Erik
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Jonsson, Lage
    Luleå tekniska universitet.
    Physical behaviour of slag in a 107-tonne ladle: production scale experiments and theoretical simulation2003In: Scandinavian journal of metallurgy, ISSN 0371-0459, E-ISSN 1600-0692, Vol. 32, no 3, p. 113-122Article in journal (Refereed)
    Abstract [en]

    The combined movement of steel, slag and gas in a ladle has been studied with the aid of a multiphase CFD model and measurements in production scale. Comparison of model data and measurements in a production ladle has been carried out for three cases: The 'open eye' created during gas stirring, the mixing of top slag during gas stirring in the CAS-OB and finally for studying sculling phenomena. It was found that the simulated 'open eye' appears as a central slag-free zone with a surrounding 'splash zone' characterized by the fact that steel is found on top of the slag. The simulated 'open eye' corresponds to the 'splash zone'. The predicted gas stirring in CAS-OB gives an efficient stirring of the top slag also. This was confirmed by noting that slag samples taken from the ladle seem to be representative of the mean slag composition. Finally, streamlines during stirring have been compared with sculling and wear observed in the production ladle. Good agreement was obtained

  • 25.
    Häggblad, Hans-åke
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Mechanics of Solid Materials.
    Nilsson, L.
    On the fit of constitutive parameters through optimization1983In: Scandinavian journal of metallurgy, ISSN 0371-0459, E-ISSN 1600-0692, Vol. 12, no 6, p. 282-284Article in journal (Refereed)
    Abstract [en]

    The need for more reliable finite element analyses of materials with complex behaviour has led to the development of new constitutive theories. These theories often have a large number of parameters which must be determined from experiments. A method is described of fitting constitutive parameters through optimization. An application is made to the Prevost multisurface plasticity theory. Good agreement is obtained between theoretical results and experimental data in the case of a multi axially loaded hard metal powder

  • 26.
    Jirestig, Jan A.
    et al.
    Luleå tekniska universitet.
    Forssberg, Eric
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Effect of impurities on the magnetic susceptibility of minerals1992In: Scandinavian journal of metallurgy, ISSN 0371-0459, E-ISSN 1600-0692, Vol. 21, no 4, p. 189-192Article in journal (Refereed)
    Abstract [en]

    The magnetic susceptibilities of minerals are strongly dependent on the presence of impurities. The effect of inclusion and solid solution type impurities has been measured and compared with theoretical and empirical models. Bulk susceptibility estimates for dia-para-magnetic particle mixtures correspond well with the theoretical model. Materials including ferri-or ferro-magnetic minerals show poor correspondence in a short interval. Empirical equations suggested by J. D. Keys and J. L. Horwood, and W. H. Brumage and C. H. Yarger for the ZnS--FeS--MnS solid solution systems have also proved useful in predicting the magnetic susceptibility of Fe and Mn rich sphalerites

  • 27. Lager, Thomas
    et al.
    Forssberg, Eric
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Comparative study of the flotation properties of jamesonite and stibnite1989In: Scandinavian journal of metallurgy, ISSN 0371-0459, E-ISSN 1600-0692, Vol. 18, no 3, p. 122-130Article in journal (Refereed)
    Abstract [en]

    The flotation properties of the mineral jamesonite, which occurs as an impurity in some chalcopyrite concentrates, were investigated and compared with those of stibnite. Jamesonite floats readily at natural pH without activation and with xanthate as the collector. The mineral can be depressed with dichromate at natural pH. Jamesonite, like stibnite, is capable of floating to some extent with frother alone

  • 28. Lager, Thomas
    et al.
    Forssberg, Eric
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Study of some antimony minerals' flotation properties in different process environments1989In: Scandinavian journal of metallurgy, ISSN 0371-0459, E-ISSN 1600-0692, Vol. 18, no 5, p. 251-257Article in journal (Refereed)
    Abstract [en]

    Flotation of antimony-bearing minerals in a complex sulphide ore from the Rakkejaur deposit has been studied in laboratory experiments. Microprobe equipment has been used to distinguish the various types of antimony mineral present in the flotation products. The results show that effective depression of the iron-rich antimony minerals can be obtained on flotation in a lime alkaline environment at pH 11.5 without increasing the losses of silver. These antimony minerals float more strongly at about pH 5.

  • 29.
    Liu, X.
    et al.
    Luleå tekniska universitet.
    Pettersson, Stig
    Luleå tekniska universitet.
    Lindström, B.
    Bioleaching of Refractory Arsenical Pyrite Concentrates to Enhance Gold Extraction1991In: Scandinavian journal of metallurgy, ISSN 0371-0459, E-ISSN 1600-0692, Vol. 20, no 6, p. 346-350Article in journal (Refereed)
    Abstract [en]

    A thermophilic species, Sulfolobus acidocaldarius, strain BC, has been used for the bioleaching of refractory arsenical pyrite concentrates to enhance Au extraction in cyanidation. The results of laboratory batch tests on two concentrates are presented. In both cases, Au extraction rates were greatly increased from < 11% with only cyanidation to > 90% with the bioleaching pretreatment. The behaviour of arsenopyrite and pyrite is described during the bio-oxidation course. Correlations are determined between the degree of the arsenopyrite/pyrite oxidation and the Au extraction rate.

  • 30.
    Moosberg-Bustnes, Helena
    et al.
    Swedish Cement and Concrete Research Institute, Stockholm.
    Lind, Lotta
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Forssberg, Eric
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Fine particulate metallurgical by-products' influence on cement hydration and strength development: an initial study2004In: Scandinavian journal of metallurgy, ISSN 0371-0459, E-ISSN 1600-0692, Vol. 33, no 1, p. 15-24Article in journal (Refereed)
    Abstract [en]

    By-products, such as dusts and sludges from metallurgical processes usually have a very fine particle size distribution and may be used, directly from the process of their origin, as a substitute for natural filler in concrete. To be able to promote the use of by-products as fillers in concrete their effect on concrete properties has to be examined. This investigation has been made in order to gain knowledge of how fine particulate by-products that contain metal oxides influence the cement hydration and concrete properties, such as strength development.

  • 31.
    Narasimhan, B.R.V
    et al.
    National Metallurgical Laboratory Madras Centre, Taramani, Chennai.
    Prabhakar, S.
    National Metallurgical Laboratory Madras Centre, Taramani, Chennai.
    Rao, K. Hanumantha
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Manohar, P.
    National Metallurgical Laboratory Madras Centre, Taramani, Chennai.
    Gnanam, F.D.
    National Metallurgical Laboratory Madras Centre, Taramani, Chennai.
    Utilization of ferrous leach liquor to synthesize gamma ferric oxide2002In: Scandinavian journal of metallurgy, ISSN 0371-0459, E-ISSN 1600-0692, Vol. 31, no 3, p. 201-205Article in journal (Refereed)
    Abstract [en]

    The production of pigment grade titanium dioxide involves leaching of ilmenite with acids that also results in the formation of ferrous sulfate/chloride. Usually the ferrous salts are spray-roasted to regenerate the sulfuric acid/hydrochloric acid for recycling. However, the quantities of ferrous leach liquor and the capital cost of the regeneration plant dictate the viability of regeneration of acids. In the case of smaller ilmenite processing plants, the regeneration of the acid is not economical and warrants alternate methods of using the ferrous leach liquor. The present paper describes a novel method of synthesizing gamma ferric oxide from ferrous leach liquor obtained from a titanium dioxide pigment plant situated in south India. The partial precipitation technique is employed to purify the ferrous leach liquor and make it suitable for the synthesis. Sodium carbonate is used to precipitate iron as ferrous carbonate and is directly calcined to yield gamma ferric oxide. Experiments were conducted to study the effect of heating rate, condition of the precipitate, whether dry or wet, and extent of oxidation of ferrous on the magnetic properties such as coercivity and specific magnetization. Cobalt-doped gamma ferric oxide was also prepared by the carbonate precipitation route.

  • 32.
    Navara, E.
    et al.
    Luleå tekniska universitet.
    Easterling, K.E.
    Luleå tekniska universitet.
    Martensite formation in the haz of welded microalloyed steels1982In: Scandinavian journal of metallurgy, ISSN 0371-0459, E-ISSN 1600-0692, Vol. 11, no 4, p. 169-172Article in journal (Refereed)
    Abstract [en]

    THE WELDING OF FINE GRAINED MICROALLOYED STEELS CAN BRING ABOUT CONSIDERABLE GRAIN GROWTH IN THE HEAT AFFECTED ZONE (HAZ) AND THIS IN TURN INCREASES THE POSSIBILITY OF MARTENSITE FORMATION. WELDING DIAGRAMS HAVE RECENTLY BEEN DEVELOPED FORPREDICTING THE AMOUNT OF GRAIN GROWTH IN THE HAZ OF VARIOUSSTEELS. THE OBJECT OF THE PRESENT WORK WAS TO STUDY THE AMOUNT OF MARTENSITE AS A FUNCTION OF GRAIN SIZE IN THE HAZ, AND TO SUPERIMPOSE THESE FIGURES ON THE WELDING DIAGRAM OF A NB-STEEL

  • 33.
    Nilsson, L.
    et al.
    Luleå tekniska universitet.
    Oldenburg, Mats
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Mechanics of Solid Materials.
    On tensile fracture and wave propagation in granular materials1983In: Scandinavian journal of metallurgy, ISSN 0371-0459, E-ISSN 1600-0692, Vol. 12, no 6, p. 299-301Article in journal (Refereed)
    Abstract [en]

    In the analysis the material is treated as plastic fracturing. A continuum approach to tensile fracturing is related to fracture mechanical concepts. The rate of strain-softening is obtained from the rate of fracture energy being released. Material anisotropy due to the formation of crack-planes is accounted for. The proposed strain-softening tensile fracturing model is implemented in a finite element program for wave propagation analysis. The strain-softening model is compared to an ideal brittle model in analysis of wave propagation in a concrete rod.

  • 34.
    Nilsson, L.
    et al.
    Luleå tekniska universitet.
    Pettersson, Stig
    Luleå tekniska universitet.
    Sandström, Åke
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Iron and arsenic removal from bacterial leaching effluents by precipitation with limestone1994In: Scandinavian journal of metallurgy, ISSN 0371-0459, E-ISSN 1600-0692, Vol. 23, no 4, p. 184-189Article in journal (Refereed)
    Abstract [en]

    By bacterial leaching of bulk concentrates of complex sulphide ores, acid leachates are produced which besides valuable metals as zinc and copper also contain high concentrations of impurities such as iron and arsenic, In order to evaluate the proper conditions for removal of iron and arsenic by precipitation as ferric arsenate with limestone, a series of batch precipitation experiments was conducted at various pH values in the range 2-6. The results from these tests showed that pentavalent arsenic and ferric iron can be effectively precipitated to low concentrations when the precipitation is carried out at pH 3 without causing losses of zinc; however, the ferrous iron, approximately 1 g/l, remains in solution. When the precipitation is carried out at pH above 3 in order to oxidize ferrous iron, unacceptable high zinc losses were obtained.

  • 35.
    Nilsson, L.
    et al.
    Luleå tekniska universitet.
    Pettersson, Stig
    Luleå tekniska universitet.
    Sandström, Åke
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    New process for zinc recovery from bacterial leach solutions1996In: Scandinavian journal of metallurgy, ISSN 0371-0459, E-ISSN 1600-0692, Vol. 25, no 4, p. 161-171Article in journal (Refereed)
    Abstract [en]

    As an alternative to traditional treatment of complex zinc-containing sulphide ores, application of bio-hydrometallurgical routes can be a possible and economical alternative. When the bio-leaching of such ores or concentrates takes place, dilute acidic leachates are produced, which in addition to valuable metals as zinc and copper, also contain high concentrations of impurities such as iron and arsenic. The aim of the present study has been to develop a new process for recovery of zinc and other base metal values from such leachates. In this process, iron and arsenic are precipitated from the leachate with limestone at pH 3. After a solid/liquid separation step the pH is further increased by lime addition whereby zinc, copper and cadmium are precipitated. The hydroxides formed are after a solid/liquid separation step dissolved with sulphuric acid generated by electrowinning of zinc. As a result a solution concentrated in zinc is produced, which after solid/liquid separation and purification, is fed to the tank house for electrolytic production of zinc metal. The results showed that the proposed process is capable of recovering metal values from leachates of variable compositions. Furthermore, the process can handle solutions which contain chloride, thus giving the method an advantage over conventional zinc electrowinning processes. Raw materials and neutralising agents which contain fluoride and to a lesser extent magnesium must, however, be avoided.

  • 36. Nurni, Viswanathan
    et al.
    Sridhar, Seetharaman
    Department of Materials Science and Engineering, Carnigie Mellon University, Pittsburgh.
    Mills, K.C.
    Department of Materials, Imperial College of Science, Technology and Medicine, London.
    Sichen, Du U.
    Department of Metallurgy, Royal Institute of Technology, Stockholm.
    Mathematical model to simulate the temperature and composition distribution inside the flux layer of a continuous casting mould2002In: Scandinavian journal of metallurgy, ISSN 0371-0459, E-ISSN 1600-0692, Vol. 31, no 3, p. 191-200Article in journal (Refereed)
    Abstract [en]

    A model is presented to predict the mass transport and heat transfer in a continuous casting mould flux bed. Physically consistent micromodels for carbon burning, evaporation of volatiles and thermophysical properties in the mould flux layer have been combined with a one-dimensional finite-difference model of the continuous casting mould flux bed. The sensitivity of the model to bed height, flux consumption rate, carbon burning and powder particle size is investigated for a mould flux composition corresponding to an industrial casting powder.

  • 37.
    Olika, B.
    et al.
    Luleå tekniska universitet.
    Pan, Y.
    Björkman, Bo
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Grip, Carl-Erik
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Numerical simulation and industrial investigation on the melt stratification phenomena in ladles holding molten steel1996In: Scandinavian journal of metallurgy, ISSN 0371-0459, E-ISSN 1600-0692, Vol. 25, no 1, p. 18-26Article in journal (Refereed)
    Abstract [en]

    The melt stratification phenomenon, which results from the natural convection in ladles holding molten steel, is of fundamental importance for the temperature control in the continuous casting process. The progressively increasing stress on the quality of continuously cast products necessitates much tighter tundish temperature control, which in turn will require a more precise definition of the extent of melt temperature stratification in ladles. For this reason, ladle melt stratification phenomena were studied both by numerical simulations, using the PHOENICS package, and by plant measurements at SSAB Tunnplat AB's steelworks in Lulea. The parameters studied in the numerical simulations were the fluid flow velocity field, the temperature distribution field, ladle initial heat content and height to diameter ratio of ladles. One of the important boundary conditions that was used in these numerical simulations was the time and geometry-dependent heat loss rate through the ladle walls, which is the major cause of the natural convection. This transient boundary condition was obtained from the temperature simulation model TempSim. Steel temperatures measured at different positions along the ladle height are compared in the paper with results from the numerical calculations. The possibility of expressing the stratification with a simple formula was discussed. However, to propose this model for industrial use, experimental verification with prolonged holding time is needed

  • 38. Olika, Bekele
    et al.
    Björkman, Bo
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Prediction of steel temperature in ladle through time/temperature simulation1993In: Scandinavian journal of metallurgy, ISSN 0371-0459, E-ISSN 1600-0692, Vol. 22, no 4, p. 213-219Article in journal (Refereed)
    Abstract [en]

    Plant measurements were done for selected parameters, influencing the heat content in ladle lining and the steel in ladle, from tapping time to the start of casting. Temperature profiles in ladle lining were measured throughout the ladle cycle by thermocouples installed in the lining. Measured parameters, such as molten steel temperature and ladle lining temperature profiles at the start of the ladle cycle, were used as initial input to the heat balance simulation model TempSim. Calculated and measured temperatures were compared and the possibility of using the heat balance model TempSim for prediction of steel temperature was demonstrated. The results obtained show that it is possible to predict steel temperatures in ladle at arrival to the casting station with a standard deviation of ±3°. The agreement between measured and calculated lining sublayer temperatures is also good. Effects on the melt temperature in ladle of lining wear, length of tapping time, amount of slag tapped from the primary furnace and lining temperature profile were also highlighted in this work. In particular, ladle lining wear and the length of the tapping influence the steel temperature in the ladle considerably

  • 39.
    Orumwense, Osawaru A
    et al.
    Luleå University of Technology.
    Forssberg, Eric
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Ultrafine grinding of muscovite in close packed media mill1990In: Scandinavian journal of metallurgy, ISSN 0371-0459, E-ISSN 1600-0692, Vol. 19, no 4, p. 201-206Article in journal (Refereed)
    Abstract [en]

    This paper presents the results of batch vibration milling of mica. Grinding time or energy input, and solid and dispersant concentrations were the variables. Product fineness is greatly influenced by energy input, solid concentration, and mill settings. Muscovite can be ground efficiently to a high degree of fineness at a relatively high energy expenditure. Particle shape is preserved or improved presumably due to the predominance of exfoliation as opposed to true fracture as the mode of particle breakage.

  • 40.
    Pan, Yuhua
    et al.
    Luleå tekniska universitet.
    Grip, Carl-Erik
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Björkman, Bo
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Numerical studies on the parameters influencing steel ladle heat loss rate, thermal stratification during holding and steel stream temperature during teeming2003In: Scandinavian journal of metallurgy, ISSN 0371-0459, E-ISSN 1600-0692, Vol. 32, no 2, p. 71-85Article in journal (Refereed)
    Abstract [en]

    Numerical experiments were performed on fluid flow and heat transfer in 107-tonne steel ladles by 3-step implementations of numerical models. In the first step, a 1-dimensional numerical model was used to predict heat conduction fluxes through the ladle wall, bottom and top slag layer. In the second step, by means of computational fluid dynamics (CFD) modelling and employing the predicted heat loss fluxes as thermal boundary conditions, a 2-dimensional CFD model was applied to simulate natural convection in steel ladles during the holding period before teeming. In the third step, a 3-dimensional CFD model was implemented to further simulate fluid dynamics in the same ladles with drainage flows during teeming. Using these mathematical numerical models, the bulk cooling rate of the steel melt, the extent of thermal stratification during holding and the steel stream temperature during teeming were investigated for 2 types of 107-tonne steel ladles lined, respectively, with alumina and spinel in walls. In these investigations, the following 4 parameters were considered: (i)ladle lining inside surface (hot-face) temperature before tapping, (ii)top slag layer thickness, (iii) holding time and (iv) teeming rate. An important result of these investigations is that the concerned parameters all significantly influence the steel stream temperature during teeming, and the differences in teeming stream temperatures among different ladles, caused by these parameters, can be up to 20 deg C, which may be essential to temperature control in tundishes during continuous casting.

  • 41.
    Pei, Benyan
    Luleå tekniska universitet.
    Assessment of arsenic activity in molten copper1993In: Scandinavian journal of metallurgy, ISSN 0371-0459, E-ISSN 1600-0692, Vol. 22, no 1, p. 24-29Article in journal (Refereed)
    Abstract [en]

    The literature on the experimentally measured arsenic activities in molten copper alloys was reviewed. It was found that the arsenic activity coefficients at infinite dilution in molten copper, γAs0, differ by one to three orders of magnitude in the temperature range 1273 to 1423 K. Such discrepancies may be due to different arsenic thermodynamic and vapor pressure data used by different authors. Based on more accurate data for arsenic vapour species, vapour phase equilibria at various temperatures have been calculated. Tetramer As4 is the predominant species in the vapour phase saturated with solid or liquid arsenic. When arsenic vapour, saturated previously with solid arsenic, is heated to temperatures above 1273 K, As2 becomes the predominant species. Recalculation of the arsenic activities in molten copper from literature data shows that RTlnγAs0 is fairly constant and has an average value of -69 229 J/mol in the temperature range 1273 to 1423 K.

  • 42.
    Pei, Benyan
    et al.
    Luleå tekniska universitet.
    Rosenqvist, Terkel
    Thermodynamics of oxide-sulphide equilibria for chromium, vanadium and titanium1991In: Scandinavian journal of metallurgy, ISSN 0371-0459, E-ISSN 1600-0692, Vol. 20, no 6, p. 331-340Article in journal (Refereed)
    Abstract [en]

    The equilibrium between oxides and sulphides of chromium, vanadium, and titanium was studied at 1000-1400°C by means of a H2-H2S-H2O gas mixture according to the reaction: MeOy + x H2S + (y - x) H2 = MeSx + y H2O, where Me denotes one of the three metals. Measurements were made in the range of log (H2S/H2) between about -2 and -1. Of the three oxides, chromium oxide is sulphided most easily and titanium oxide least easily. The stoichiometric coefficients x and y were derived from the (H2S/H2) and (H2O/H2) ratios and their interrelation. The results were combined with known Gibbs energy data for MeOy, H2S and H2O to give ΔGxο for the reaction: Me + (x/2) S2 = MeSx. The stability of the sulphides relative to the elements increases in the sequence chromium to titanium. Results were combined with literature data for the sulphur potentials in the solid solution range MeSx to give ΔGxο as function of x. For each of the three metals ΔGxο decreases with increasing x value to a minimum where the S2 potential reaches 1 atm. This minimum occurs at about 59 atom % S for chromium, about 60 atom % S for vanadium and about 62 atom % S for titanium

  • 43.
    Ping, Ma
    et al.
    Luleå tekniska universitet.
    Lindblom, Bo
    LKAB.
    Björkman, Bo
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Experimental studies on solid-state reduction of pickling sludge generated in the stainless steel production2005In: Scandinavian journal of metallurgy, ISSN 0371-0459, E-ISSN 1600-0692, Vol. 34, no 1, p. 31-40Article in journal (Refereed)
    Abstract [en]

    Neutralized pickling sludge generated during stainless steel production contains large amounts of calcium fluoride, water and a relatively low metal content, which makes it difficult to directly recycle back to the steelmaking process. It would also pose a potential environmental problem if deposited outdoors over a long term. However, metals such as iron, nickel and chromium, in the form of oxides and/or hydroxides, as well as calcium fluoride in the sludge, are of economic concern to stainless steel makers. Therefore, to develop an economically and technically suitable recycling process, a comparison study on reducing both pickling sludge and mixtures of metal oxides, using petroleum coke (P-coke) and graphite as reductant, respectively, was carried out at temperatures up to 1400°C using thermogravimetric (TG) analysis. Meanwhile, laboratory-scale tests on reducing pickling sludge, using P-coke as reductant, were also conducted in a Tammann fur nace at 800-1200°C. Results of the comparison study by TG demonstrate that the reduction behaviour of pickling sludge may be approached by the reduction behaviour of the metal oxide mixture having the same composition as those in the pickling sludge. Results of the Tammann furnace tests show that temperature has a significant influence on reduction. The reduced metals in the reduction products exist mostly in the form of alloys such as '(Fe,Ni)' and 'Cr-Fe-Ni'.

  • 44.
    Ping, Ma
    et al.
    Luleå tekniska universitet.
    Lindblom, Bo
    LKAB.
    Björkman, Bo
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Mechanism study on solid-state reduction in the Fe2O 3-NiO-Cr2O3-C system using thermal analyses2005In: Scandinavian journal of metallurgy, ISSN 0371-0459, E-ISSN 1600-0692, Vol. 34, no 1, p. 22-30Article in journal (Refereed)
    Abstract [en]

    In order to clarify the interactions among metal oxides during reduction of pickling sludge, the reduction mechanism of the metal oxide mixture, Fe 2O3-NiO-Cr2O3, which simulates the composition of these metal oxides in pickling sludge, was studied using graphite as a reductant, by means of thermal analysis techniques. X-ray diffraction analysis was used for characterization of reduction products. In addition to the reduction test on the metal oxide mixture mentioned above, for comparison, separate tests on the reduction of Fe2O3, NiO and Cr 2O3 were also conducted. The results demonstrate that through formation of a transitional compound 'FeCr2O4', Fe2O3 promotes the complete reduction of Cr 2O3 at a temperature lower than that required for reducing pure Cr2O3. On the other hand, Cr2O 3 hinders the reduction of Fe2O3 at lower temperatures. The whole reduction process may be classified as five distinguishable reduction stages in which possible reactions were proposed to represent the reduction mechanism. The reduced metals in the final product exist primarily in the form of solid solutions, such as 'Cr-Fe-Ni', which mainly containing '(Fe,Ni)' and '(Fe,Cr)', and small amounts of carbides, such as (Cr,Fe)7C3 and/or Cr7C3

  • 45.
    Porter, D.A.
    Luleå tekniska universitet.
    High-resolution microanalysis of cellular recipitation in Mg-Al alloys1977In: Scandinavian journal of metallurgy, ISSN 0371-0459, E-ISSN 1600-0692, Vol. 6, no 1, p. 18-Article in journal (Other academic)
  • 46.
    Porter, D.A.
    et al.
    Luleå tekniska universitet.
    Easterling, K.E.
    Luleå tekniska universitet.
    Dynamic studies of the tensile deformation and fracture of pearlite using high-resolution 200-KV sem1978In: Scandinavian journal of metallurgy, ISSN 0371-0459, E-ISSN 1600-0692, Vol. 7, no 2, p. 55-56Article in journal (Other academic)
  • 47.
    Rutqvist, Staffan
    et al.
    Luleå tekniska universitet.
    Bergman, Dan
    Luleå tekniska universitet.
    Olika, Bekele
    Luleå tekniska universitet.
    Determination of ladle lining heat content with radiation thermometer1990In: Scandinavian journal of metallurgy, ISSN 0371-0459, E-ISSN 1600-0692, Vol. 19, no 3, p. 146-152Article in journal (Refereed)
    Abstract [en]

    Most steel plants are currently operating with 100% continuous casting, often in sequence. This gives an increased demand for accurate process control of both the steel temperature and the time schedule. A normal steel plant practice gives too large a difference from heat to heat regarding the steel temperature in the ladle and the tundish, often due to the varying heat content of the ladle lining. One common practice to obtain an accurate steel temperature control in the tundish is to build in temperature and time buffers in the ladle metallurgy schedule, resulting in increasing costs for the higher temperature in the furnace and lower productivity. The aim of this project has been to study the possibility of measuring the heat content of the ladle lining by a non-contact method. Plant trials have been carried out at a Swedish steel plant, where the heat content of the ladle lining was determined by measuring the lining time-temperature relation with a radiation thermometer. By using the measured heat content as the input in a simulation model, it has been possible to calculate the steel temperature lapse. The difference between the calculated and actual measured steel temperature has been acceptable, with a standard deviation of ±3.5°C. This shows that it is possible to use a non-contact temperature measurement in connection with a calculation model to predict accurately the steel temperature lapse in the ladle

  • 48.
    Ryden, J.
    et al.
    Svenskt Stål.
    Arén, Björn
    Luleå tekniska universitet.
    Wuopio, U.
    Direct quenching of wide flange beams in pilot plant experiments1984In: Scandinavian journal of metallurgy, ISSN 0371-0459, E-ISSN 1600-0692, Vol. 13, no 4, p. 187-192Article in journal (Refereed)
    Abstract [en]

    Experiments have shown that H-profiled beams of a mild steel can reach improved strength by direct quenching after final rolling. Cooling rates within the range 34 degree C/s- 64 degree C/s were studied. Material testing has shown increased yield strength values by 20-110%. Toughness in some cases decreased and in other cases increased depending on process parameters. The structure contained bainite, ferrite and martensite

  • 49.
    Samuelsson, Caisa
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Björkman, Bo
    Dust forming mechanisms in the gas cleaning system after the copper converting process: (I). Sampling and characterisation1998In: Scandinavian journal of metallurgy, ISSN 0371-0459, E-ISSN 1600-0692, Vol. 27, no 2, p. 54-63Article in journal (Refereed)
    Abstract [en]

    Recovery of metals in special processes from dust with a low content of each metal can generally not be accomplished with any economic gain. A controlled dust generation whereby the dust would be enriched with specific metals would facilitate the possibilities of recovering metals from such dusts. The aim of this work was to study dust formation in the gas cleaning system after the copper converting process and to examine the possibilities for a selective dust collection. Dust samples from different positions in the gas cleaning system were characterised. Vaporised metals, e.g., compounds of Pb, Zn, As and Bi, have condensed in the converter hood, depending on temperature drop of the gas to less than 700°C, forming the so-called chemical dust. The chemically-formed dust has a smaller particle size that the mechanically transported particles, matte, slag and SiO2, and will therefore to a large extent be transported a longer distance in the gas cleaning system

  • 50.
    Samuelsson, Caisa
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Björkman, Bo
    Dust forming mechanisms in the gas cleaning system after the copper converting process: (II). Thermodynamic studies1998In: Scandinavian journal of metallurgy, ISSN 0371-0459, E-ISSN 1600-0692, Vol. 27, no 2, p. 64-72Article in journal (Refereed)
    Abstract [en]

    Thermodynamic calculations were used to study the dust-forming mechanisms during the copper converting process and to study the possibilities for achieving a controlled dust generation through selective condensation. The evaporation of Zn, Pb, Bi, As and Sb from the melt during the copper converter process and their condensation at decreasing temperatures was simulated. Comparison with experimental data from the full-scale process shows a good qualitative agreement. It was therefore considered possible to use the thermodynamic model to predict the generation of chemical dust in the gas cleaning system at various temperatures and varying amounts of leakage air. A selective condensation of Pb, Zn and As at various temperatures could according to thermodynamic calculations, be possible at high temperatures. A selective condensation of metals requires a closed gas cleaning system or a gas cleaning system with a limited amount of leakage air in order to maintain the desired temperature level

12 1 - 50 of 70
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