Browsing by Author "Sukhomlinov, Dmitry"
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Item Arsenic Condensation and Reaction Mechanisms in Flash Smelting Off-Gas Line Conditions(Springer, 2023-10) Wan, Xingbang; Sukhomlinov, Dmitry; Taskinen, Pekka; Lindgren, Mari; Michallik, Radoslaw; Jokilaakso, Ari; Department of Chemical and Metallurgical Engineering; Metallurgy (MTG); Outotec Research Center; Geological Survey of Finland; Central South UniversityArsenic is a common impurity element in sulfide concentrates. It tends to accumulate in the flue dust of smelting furnace due to the volatility and internal circulation of the flue dust practiced in the smelting-converting process chain. The only outlets for arsenic are anodes and discard slag. Arsenic condensation in dust-free conditions was studied below 800 °C where the gas atmosphere was controlled by SO2-air-N2 gas mixtures. Based on these experimental results, we confirm the kinetically constrained formation mechanism of the arsenic-containing dust, and its speciation into metallic, oxidic (III, V), and sulfidic species. The influences of temperature and atmosphere on the speciation of arsenic were compared with industrial data and discussed. Graphical Abstract: [Figure not available: see fulltext.]Condensed arsenic‐bearing particles collected by electrophoretic forces on the surface of fused SiO2 in SO2‐O2 atmospheres: the crystal morphology shows euhedrally facetted As2O3 crystals and initially molten As‐OSalloy droplets together with poorly crystallized AsS x particles.Item Behavior of Ga, In, Sn, and Te in Copper Matte Smelting(SPRINGER, 2019-12-01) Sukhomlinov, Dmitry; Klemettinen, Lassi; O’Brien, Hugh; Taskinen, Pekka; Jokilaakso, Ari; Department of Chemical and Metallurgical Engineering; Metallurgy (MTG); Geological Survey of Finland; Norwegian University of Science and TechnologyThe distributions of Ga, In, Sn, and Te between copper-iron mattes and silica-saturated iron silicate slags over a wide range of matte grades 55 to 75 pct Cu were determined at 1300 °C using a gas-phase equilibration-quenching technique and direct phase composition analysis by Electron Probe X-ray Microanalysis and Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry. Alumina from aluminum, a typical minor element of electric and electronic copper scrap, and lime were adopted as slag modifiers for increasing the trace element recoveries. Gallium and tin were distributed predominantly in the slag, indium preferred sulfide matte at low matte grades and slag at high, whereas tellurium strongly favored the sulfide matte in particular in high matte grades. The slag modifiers alumina and lime had a minor impact on the distribution coefficients of gallium and tin, but for indium and tellurium the distribution coefficients were more strongly affected by the basic oxides. The strong tendencies of tin and tellurium to vaporize at the experimental temperature were confirmed.Item A Crucial Step Toward Carbon Neutrality in Pyrometallurgical Reduction of Nickel Slag(Springer, 2023-12) Attah-Kyei, Desmond; Sukhomlinov, Dmitry; Tiljander, Mia; Klemettinen, Lassi; Taskinen, Pekka; Jokilaakso, Ari; Lindberg, Daniel; Department of Chemical and Metallurgical Engineering; Metallurgical Thermodynamics and Modelling; Metallurgy (MTG); Geological Survey of FinlandThis study aims at recovering valuable metals from nickel slag by employing pyrometallurgical techniques. A large amount of slag is generated during the nickel matte smelting. Nickel slag contains valuable elements such as copper, nickel, and cobalt, which can be recovered. Disposal of this slag results in loss of resources and may cause pollution of the environment. It is important to retrieve these metals for environmental and economic reasons. In this study, the slag was reacted with non-fossil reducing agents (biochar) which were produced from hydrolysis lignin and black pellet biomass by pyrolysis at 600 and 1200 °C, and with metallurgical coke for comparison. The reduction experiments were done at 1400 °C for 15, 30, and 60 min under inert gas atmosphere. The samples were quickly quenched and analyzed with Electron Probe X-ray Microanalysis. The results showed that the use of biochar resulted in faster reaction kinetics in the reduction process compared to coke. Moreover, thermodynamic modeling was also performed using Factsage to simulate equilibria with different amounts of biochar. The metal-to-slag distribution coefficient calculated from the results of thermodynamic modeling was consistent with experimental results. Graphical Abstract: [Figure not available: see fulltext.].Item Distribution of Ni, Co, Precious, and Platinum Group Metals in Copper Making Process(SPRINGER, 2019-08-15) Sukhomlinov, Dmitry; Klemettinen, Lassi; Avarmaa, Katri; O’Brien, Hugh; Taskinen, Pekka; Jokilaakso, Ari; Department of Chemical and Metallurgical Engineering; Metallurgy (MTG); Geological Survey of FinlandThe distribution coefficients of Ni, Co, Ag, Au, Pt, and Pd between molten copper and silica-saturated iron silicate slags (LMeCu/s) were measured experimentally. The distribution behaviors were studied under typical conditions of copper converting and fire refining, i.e., from 1250 °C to 1350 °C, and from 10 −8 to 10 −4 atm oxygen partial pressure. The coefficients were determined as the ratios of the trace element weight concentrations measured in situ, directly from the equilibrated metal and slag phases. For the quantitative elemental analysis of the phases, state-of-the-art analytic techniques, including electron probe microanalysis and laser ablation-inductively coupled plasma-mass spectrometry, were employed. The distribution coefficients LMeCu/s determined can be arranged in the following order: Pt > Au > Pd >> Ag > (Cu) > Ni > Co > (Fe).Item The distribution of trace elements in nickel flash smelting(2018-07-31) Virtanen, Olli; Taskinen, Pekka; Sukhomlinov, Dmitry; Kemian tekniikan korkeakoulu; Jokilaakso, AriMore efficient recovery of trace elements in the mining industry is a growing concern due to the ever decreasing quality of ore and the need for more pure materials in advanced applications. In order to achieve this goal we require deeper insight into the behaviour of different impurities during the smelting process. The goal of this study was to investigate the distribution of trace elements (Ge, Co, Se, Pb and Sn) between nickel matte and fayalite slag in the Direct Outotec Nickel Flash Smelting – process. The experiments were conducted with a method that includes equilibration and quenching of the sample, followed by an EPMA-analysis. All experiments were conducted at 1400ᵒC. Oxygen partial pressure varied among the experiments. Iron concentration in matte was controlled within the range of 3 to 9 wt% Fe by gas mixtures containing Ar-CO-CO2-SO2. MgO and K2O were added to some of the samples to study their effect on the distribution behaviour. Ni:Cu ratio was kept at 5:1 in all experiments and SiO2 crucibles were used during equilibration. Co and Se distribution behaviour between matte and slag was studied. The results were compared to previous studies and discussed accordingly. The addition of MgO and K2O were also studied, and had a clear effect on the distribution coefficients, with the type of effect depending on the substance in question. Ge, Pb and Sn were vaporized during the equilibration, leading to their concentrations being too low to analyse with EPMA. A more sensitive nalytical technique has to be employed to further investigate the behaviour of these elements.Item Distribution of trace elements in the blister copper – white metal system: copper blow conditions(2018-07-31) Holland, Keiran; Taskinen, Pekka; Sukhomlinov, Dmitry; Kemian tekniikan korkeakoulu; Jokilaakso, AriThe aim of this experimental work is to investigate the distribution coefficients (LXCu/Wm) of cobalt, nickel, silver, gold and palladium in copper converting conditions between the metal phase and the white metal phase. The first part of this work is a literature review, the later part describes the experimental work and presents the data. The experimental work investigates the distribution coefficients of the elements as functions of temperature ranging from 1250 C° to 1350 °C and sulphur dioxide partial pressures ranging from 0.01 to 1 atm in SO2 – Ar mixtures. The experimental work consisted of the equilibration of the samples, quenching into ice cold water, grinding and polishing of the cross sections and the analysis of concentrations in both phases by EPMA. The EPMA work was carried out at the Geological Survey of Finland (GTK). It was found that there are dependencies between the LXCu/Wm and PSO2 and temperature for silver, gold, palladium and nickel. Silver was found to be more concentrated to the metal phase at 1250 °C and 1 atm P(SO2) with a value for LAgCu/Wm decreases as a function of increasing temperature and decreasing P(SO2). LNiCu/Wm is found to increase with increasing temperature and P(SO2). For cobalt it was found that there was a dependency between LXCu/Wm and PSO2. LCoCu/Wm increases as P(SO2) decreases, LCoCu/Wm falls from 0.85 to 0.15. The concentrations of silver in certain experiments, gold and palladium in the white metal phase fell below the detection limit of the EPMA. Both gold and palladium were found to be more concentrated to the metal phaseItem Experimental Determination of Phase Equilibria in the REM2O3-SiO2 (REM = Y/Yb/La) Systems at Elevated Temperature(SPRINGER, 2021-01) Xia, Longgong; Sukhomlinov, Dmitry; Ye, Fengchun; Liu, Zhihong; Taskinen, Pekka; Department of Chemical and Metallurgical Engineering; Central South UniversityPhase relations in the REM2O3-SiO2 (REM = Y/Yb/La) systems have been studied using the equilibration/quenching/scanning electron microscopy (SEM)-electron probe microanalysis (EPMA) technique. The solvus and liquidus between 1400°C and 1650°C have been determined. The results obtained in this study show that a maximum of 0.57 wt.% Yb2O3 can dissolve in SiO2 phase, while the maximum solubility of La2O3 and Y2O3 in SiO2 phase was 0.22 wt.% and 0.07 wt.%, respectively. Correspondingly, SiO2 shows low solubility in La2Si2O7, and nearly does not dissolve in Y2Si2O7 or Yb2Si2O7. No liquid phase was detected in the Y2O3-SiO2 or Yb2O3-SiO2 system in the temperature range of interest. One oxide liquid phase comprising 39.27 wt.% SiO2 and 59.07 wt.% La2O3 was found in the La2O3-SiO2 system sample equilibrated at 1653°C, revealing that the eutectic point temperature between La2Si2O7 and SiO2 is located between 1600°C and 1653°C. Results of this study were compared with previous observations, revealing significant differences.Item Ignition and combustion of synthetic nickel mattes in simulated flash smelting conditions(Elsevier Ltd, 2024-02) Chen, Min; Sukhomlinov, Dmitry; Taskinen, Pekka; Grimsey, David; Rich, Anthony; Jokilaakso, Ari; Department of Chemical and Metallurgical Engineering; Metallurgy (MTG); Metallurgical Thermodynamics and Modelling; BHP Group LtdThe ignition and oxidation behavior of synthesized sulfur-lean nickel mattes was investigated using a laminar flow furnace simulating the conditions in the flash smelting reaction shaft to explore the ignition and oxidation processes of sulfur-lean electric furnace mattes obtained from slag cleaning. The experiments were conducted at 800–1100 °C with 40–85 vol% O2 in the reaction gas. Scanning electron microscopy equipped with energy-dispersive X-ray spectrometry was used to analyze the surface morphology and mineralogical compositions of the samples. Chemical analysis was employed to determine the sulfur remaining in the samples. The ignition temperature of the sulfur-lean nickel mattes was found to be below 800 °C. The highest sulfur removal from mattes was achieved under the most oxidizing conditions. The oxidation of the metallized nickel mattes started with preferential oxidation of iron and sulfur, forming sulfur dioxide and a porous iron oxide-rich rim. Particles were observed to melt completely and even to fragment due to fast combustion reactions and the formation of sulfur dioxide inside. The present results provide valuable insights into the mechanism of sulfur-lean nickel matte smelting in flash smelting furnaces.Item Impact of MgO and K2O on Slag-Nickel Matte Equilibria(Springer New York, 2019-12-01) Sukhomlinov, Dmitry; Virtanen, Olli; Latostenmaa, Petri; Jokilaakso, Ari; Taskinen, Pekka; Department of Chemical and Metallurgical Engineering; Boliden Harjavalta OySlag chemistry of the direct nickel matte smelting was studied in typical industrial high-grade nickel matte smelting conditions at 1400 °C and 0.1 atm pSO2. The experimental technique used involved equilibration, quenching and direct elemental phase composition analysis by Electron Probe X-ray Microanalysis. Magnesia and potassia, a typical gangue constituent of sulfidic nickel concentrates and a common impurity of industrial grade silica flux (sand), respectively, were adopted as slag modifiers in concentrations typical to industrial operations. Their effects on oxidation degree of the nickel-copper-iron matte and equilibrium concentrations of Ni and Cu in the slag were studied as a function of oxygen partial pressure. Solubility of silica in the slag increased significantly with additions of MgO and K2O in the constrained case studied, at silica saturation. Equilibrium concentrations of Ni and Cu in the slag containing MgO and K2O were about a quarter lower compared to the pure iron silicate slag, in the entire oxygen partial pressure range studied.Item Laser Flash Analysis Technique - Theory and Practice(2022-05-27) Savelainen, Joonas; Sukhomlinov, Dmitry; Kemiantekniikan korkeakoulu; Aromaa, JariItem Microstructure and thermal properties of dissimilar M300–CuCr1Zr alloys by multi-material laser-based powder bed fusion(University of Science and Technology Beijing, 2024-01) Li, Xiaoshuang; Sukhomlinov, Dmitry; Que, Zaiqing; Department of Chemical and Metallurgical Engineering; Metallurgy (MTG); Aerosint SA; VTT Technical Research Centre of FinlandMulti-material laser-based powder bed fusion (PBF-LB) allows manufacturing of parts with 3-dimensional gradient and additional functionality in a single step. This research focuses on the combination of thermally-conductive CuCr1Zr with hard M300 tool steel. Two interface configurations of M300 on CuCr1Zr and CuCr1Zr on M300 were investigated. Ultra-fine grains form at the interface due to the low mutual solubility of Cu and steel. The material mixing zone size is dependent on the configurations and tunable in the range of 0.1–0.3 mm by introducing a separate set of parameters for the interface layers. Microcracks and pores mainly occur in the transition zone. Regardless of these defects, the thermal diffusivity of bimetallic parts with 50vol% of CuCr1Zr significantly increases by 70%–150% compared to pure M300. The thermal diffusivity of CuCr1Zr and the hardness of M300 steel can be enhanced simultaneously by applying the aging heat treatment.Item Modelling Charring and Burning of Spruce and Pine Woods During Pyrolysis, Smoldering and Flaming(Springer, 2023-09) Rinta-Paavola, Aleksi; Sukhomlinov, Dmitry; Hostikka, Simo; Department of Civil Engineering; Department of Chemical and Metallurgical Engineering; Performance in Building Design and Construction; Metallurgy (MTG)The goal of this work is to develop a material model for Norway spruce and Scots pine woods for use in performance-based fire safety design to predict char front progress and heat release in burning timber. For both woods a set of two different models is estimated: one that assumes wood as a single component and another that considers the pyrolysis of wood principal components independently (single and parallel reactions models, respectively). The material models are calibrated using cone calorimeter experiments. The models are intended for a number of different fire scenarios, such as fully developed fire with only little oxygen in the compartment, or the decay period after flaming with exposed char still smoldering. For both spruce and pine, the single and parallel reactions models are able to predict the experiments in the scale of cone calorimeter with near-equal accuracy. Hence, the single reaction model emerges as the preferable level of complexity when modelling charring and heat release, avoiding the increased uncertainty associated with the additional parameters of the parallel reactions model. When scaling up to the simulations of large scale fire tests, the models can predict the char front progress, but the final temperature profile differs from the experimental. The effects of crack forming in the char layer is one of the likely causes, but its mechanisms are not sufficiently known. Therefore, we suggest a closer study on crack formation in wood under fire as future research.Item Oxidation of nickel concentrates in simulated reaction shaft conditions of the flash smelter(Elsevier Ltd, 2024-10) Chen, Min; Sukhomlinov, Dmitry; Taskinen, Pekka; Grimsey, David; Rich, Anthony; Jokilaakso, Ari; Department of Chemical and Metallurgical Engineering; Metallurgy (MTG); BHP Group LtdThe suspension oxidation of nickel sulfide concentrates in flash smelting conditions was studied using a laboratory-scale laminar flow furnace. The effects of temperature (800–1100 °C) and oxygen concentration (40–85 vol%) in the process gas were investigated. The surface morphology and mineralogical compositions of samples were examined using scanning electron microscopy equipped with energy-dispersive X-ray spectrometry. The sulfur removal from concentrates was determined using chemical analysis assuming iron as a non-volatile component. It was found that ignition of the nickel concentrates started at a temperature below 800 °C. The sulfur removal from the sieved concentrates increased with increasing temperature. The oxidation was initiated with preferential oxidation of iron in sulfides forming an iron oxide-rich scale on sulfidic core.Item Phase equilibria in TiO2-rich part of the MgO–CaO–TiO2 system at 1500–1600 °C(Elsevier Limited, 2022-07-15) Chen, Min; Wan, Xingbang; Taskinen, Pekka; Sukhomlinov, Dmitry; Shi, Junjie; Michallik, Radoslaw; Jokilaakso, Ari; Department of Chemical and Metallurgical Engineering; Metallurgy (MTG); Geological Survey of Finland; Northeastern University ChinaThe equilibrium phase relations of the MgO–CaO–TiO2 system were investigated at 1500–1600 °C in air using the high-temperature isothermal equilibration of samples in platinum crucibles followed by the rapid quenching technique. The phase compositions were analyzed using an electron probe X-ray microanalyzer (EPMA). The isothermal sections at 1500 °C and 1600 °C were constructed based on the experimentally determined liquid phase compositions. The present results deviate significantly from previous observations as well as the predictions by MTDATA and FactSage using their oxide databases, in particular in the perovskite primary phase field.Item Phase equilibria of the Al2O3-SiO2-CrOx system at 1600 °C and pO2 of 10-10-10-11 atm(Elsevier Science Ltd., 2023-11) Chen, Min; Taskinen, Pekka; Sukhomlinov, Dmitry; Lindberg, Daniel; Michallik, Radoslaw M.; Jokilaakso, Ari; Department of Chemical and Metallurgical Engineering; Metallurgy (MTG); Metallurgical Thermodynamics and Modelling; Geological Survey of FinlandThe equilibrium phase relations of the Al2O3-SiO2-CrOx system were experimentally studied at 1600 °C and pO2 of 10-10-10-11 atm. The high-temperature isothermal equilibration experiments were conducted in a vertical tube furnace, followed by drop quenching and direct phase composition analysis using an Electron Probe X-ray Microanalyzer. The single liquid equilibria, liquid-solid phase equilibria including liquid-corundum, liquid-mullite, and liquid-cristobalite, as well as the three-phase equilibria of liquid-cristobalite-corundum and liquid-corundum-mullite, were observed. The 1600 °C isothermal sections of the quasi-ternary Al2O3-SiO2-CrOx phase diagram at pO2 of 10-10 and 10-11 atm were constructed. The present experimental results display significant discrepancies with the simulations by MTDATA, FactSage, and Thermo-Calc.Item Phase equilibria of the Na2O-TiO2-SiO2 system between 900 and 1600°C in air(Wiley-Blackwell, 2024-09) Santoso, Imam; Sibarani, David; Hidayat, Taufiq; Zulhan, Zulfiadi; Sukhomlinov, Dmitry; Chen, Min; Klemettinen, Lassi; Taskinen, Pekka; Lindberg, Daniel; Jokilaakso, Ari; Department of Chemical and Metallurgical Engineering; Metallurgical Thermodynamics and Modelling; Metallurgy (MTG); Bandung Institute of TechnologyThe Na2O-SiO2-TiO2 system is important for the glass, ceramic, and metallurgical industries. Its features provide information on the composition and melting temperature to be utilized during the production of glass and ceramic and during the processing of TiO2-bearing material in the metallurgical industry. The liquidus temperatures between 900 and 1600°C in the ternary system at saturation of solid SiO2, TiO2, Na2Ti6O13, Na2SiTiO5, and Na2Ti3O7 were measured using the equilibration-quenching energy-dispersive X-ray spectroscopy/Electron Probe Microanalyzer technique. A wide range of liquidus compositions were obtained with Na2O between 0 and 41.7 mol% in the SiO2- and TiO2-rich regions. The present study provides liquidus data at 1500 and 1600°C for the first time. Liquidus temperatures at various double saturations were also obtained in the present investigation to determine univariant lines in the phase diagram. The present experimental data were compared with previous investigations and computed phase diagrams. The data obtained in the present investigation can be employed to optimize the thermodynamic properties and phase diagrams of the Na2O-SiO2-TiO2 system.Item Phase equilibrium study of the CaO–SiO2–CrOx system at 1600°C in reducing atmospheres(Wiley-Blackwell, 2024-05) Chen, Min; Taskinen, Pekka; Sukhomlinov, Dmitry; Lindberg, Daniel; Michallik, Radoslaw; Jokilaakso, Ari; Department of Chemical and Metallurgical Engineering; Metallurgy (MTG); Metallurgical Thermodynamics and Modelling; Geological Survey of FinlandPhase equilibria in the CaO–SiO2–CrOx system were experimentally investigated at 1600°C and pO2 of 10−10 to 10−11 atm using the high-temperature isothermal equilibration/drop quenching/electron probe X-ray microanalysis technique. The constrained isothermal sections of the CaO–SiO2–CrOx system were constructed at 1600°C and pO2 of 10−10 to 10−11 atm based on the experimental results. The primary phase fields including cristobalite (SiO2), larnite (Ca2SiO4), (Ca,Cr)Cr2O4, and corundum (Cr2O3) were determined. Simulations by thermodynamic software MTDATA, FactSage, and Thermo-Calc were compared with the present experimental results.Item Phase relations of the MgO–SiO2–CrOx system at 1600°C in air and reducing atmospheres(Wiley-Blackwell, 2023-10) Chen, Min; Sukhomlinov, Dmitry; Taskinen, Pekka; Tiljander, Mia; Lindberg, Daniel; Jokilaakso, Ari; Department of Chemical and Metallurgical Engineering; Metallurgy (MTG); Metallurgical Thermodynamics and Modelling; Geological Survey of FinlandThe equilibrium phase relations of the MgO–SiO2–CrOx system were investigated at 1600°C in air and at pO2 of 10–10 to 10–11 atm using a high-temperature isothermal equilibration technique followed by rapid quenching and direct phase composition analyses with electron probe X-ray microanalysis. Two-phase equilibria (liquid–cristobalite, liquid–spinel, liquid–corundum, and liquid–olivine) and three-phase equilibria (liquid–cristobalite–spinel, liquid–olivine–spinel, liquid–spinel–corundum, and cristobalite–spinel–corundum) were observed. The 1600°C isothermal sections at various oxygen partial pressures were constructed for the MgO–SiO2–CrOx system based on the experimentally determined liquid and solid compositions. Data from the literature and the predictions by FactSage and MTDATA software were compared with the present experimental results.Item Prosessiparametrien vaikutus alkuainejakaumiin kuparin Peirce-Smith -konvertointiprosessin aikana(2016-11-22) Marjakoski, Miikka; Naakka, Ville; Sukhomlinov, Dmitry; Kemian tekniikan korkeakoulu; Taskinen, PekkaKonvertointiprosessi on kuparin valmistuksessa alkuaineiden jakautumisen kannalta yksi kriittisimmistä prosessivaiheista. Rikastelaatujen heiketessä erilaisia epäpuhtaus- ja hivenaineita esiintyy kuparin valmistus¬prosesseissa kasvavissa määrin. Tämän vuoksi kuparin tuottajat tarvitsevat tietoa alkuaineiden jakautumiseen vaikuttavista tekijöistä ja prosessiparametreista. Tässä diplomityössä tutkittiin alkuainejakaumia Peirce-Smith -tyyppisessä konvertteriuunissa, joten tarkastelu keskittyi kuonasta, kivifaasista, blisterikuparista ja kaasufaasista muodostuviin systeemeihin prosessivaiheesta riippuen. Tarkasteltavia alkuaineita jakaumien puolesta olivat kupari, nikkeli, koboltti, sinkki, lyijy, arseeni, vismutti sekä antimoni. Antimonin ja vismutin pitoisuudet olivat lähes poikkeuksetta kemiallisen analyysin havaintorajan alapuolella, joten näiden alkuaineiden jakautumista ei pystytty arvioimaan työn kokeellisessa osuudessa. Kuonapuhallus¬vaiheen osalta keskityttiin tutkimaan nykyistä fluksauskäytäntöä, pohjakuonien vaikutusta prosessiin sekä alkuainejakaumia kuonapuhallusvaiheen aikana. Rikkaaksi¬puhallusvaiheen osalta tutkittiin loppupisteen määritystä SO2-mittauksen avulla sekä alkuainejakaumien esitystä SO2-mittauksen funktiona. Nykyisen fluksauskäytännön analyysissä selvisi, että silikahiekkaa tulisi panostaa nykyistä vähemmän etenkin kuonapuhalluksen viimeiseen puhallusvaiheeseen, jotta kuparihäviöt eivät kasvaisi silikakyllästyksen ja tästä seuraavan kuonan viskositeetin kasvun myötä. Pohjakuonien panostuksen todettiin lisäävän kuparin, nikkelin, lyijyn ja sinkin jakautumista kuonafaasiin sekä magnetiitin massaosuutta kuonassa ensimmäisessä kuonapuhallusvaiheessa. Lisäksi pohjakuona¬panostus rikastaa kivifaasia runsaasti, jolloin jopa metallista kuparia esiintyy prosessissa ennen rikkaaksipuhallusta. Rikkaaksipuhalluksen loppupisteen määrityksessä tulee ottaa huomioon SO2-pitoisuuden lisäksi mittauksen viive sekä huuvan paine-ero, jota ei nykyisessä konvertterimallissa ole huomioitu. Paine-eron kasvun tulisi kasvattaa vuotoilman määrää ja täten laimentaa prosessikaasujen SO2-pitoisuutta, mutta regressioyhtälössä huomattiin päinvastainen vaikutus. Rikkaaksipuhalluksen alkuaine¬jakaumien esityksestä SO2-mittauksen funktiona esitettiin suunta-antavat funktiot.Item Recovery of Metals from Copper Smelting Slag Using Coke and Biochar(Springer, 2024-03) Chen, Min; Sukhomlinov, Dmitry; Taskinen, Pekka; Hamuyuni, Joseph; Michallik, Radoslaw M.; Lindgren, Mari; Jokilaakso, Ari; Department of Chemical and Metallurgical Engineering; Metallurgy (MTG); Geological Survey of Finland; Metso Research CenterWith the purpose of recovering the metal values, in this study the copper slag was reduced by coke and biochar at 1250 °C in an argon gas atmosphere using the isothermal reduction/drop quenching technique. The phase compositions of metal, matte, and slag were determined using electron probe microanalysis (EPMA). The effects of reduction time and amount of reductant were investigated. The distribution of elements between metal/matte and slag was ascertained based on the elemental concentrations determined by EPMA. It was found that copper concentration in slag can be effectively decreased to approximately 0.4–0.6 wt% within 5 min by coke and biochar. Copper and nickel can also be successfully recovered into the copper alloy phase once settling has been accomplished.
