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1
Content available Detachment and flow behaviour of anode slimes in high nickel copper electrorefining
Sahlman Mika, Aromaa Jari, Lundström Mari
Physicochemical Problems of Mineral Processing
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2024
|
Vol. 60, iss. 2
art. no. 186194
EN
Most of the world’s copper is produced via copper electrorefining, where nickel is the most abundant impurity in the process. Previously it has been suggested that nickel affects the adhesion of anode slimes on the anode as well as the porosity of the slime layer that forms. This paper investigates the effects of nickel, oxygen, sulphuric acid and temperature on the detachment of anode slimes from the anode surface. The detachment of particles as a function of both anode and electrolyte composition was studied on laboratory scale using a camera connected to a Raspberry Pi, and particle detection and movement analysed using TrackPy. The results revealed four different slime detachment mechanisms: cloud formation, individual particle detachment, cluster detachment and avalanche. These were found to be dependent on the electrolyte (0, 10, 20, 30 g/dm3 Ni2+ & 100, 200 g/dm3 H2SO4), with increasing nickel concentration promoting cluster detachment and increasing sulphuric acid concentration favouring detachment of individual particles. Anode composition (0.05-0.44 wt% O and 0.07-0.64 wt% Ni) was shown to affect the flow direction of anode slimes, with increasing nickel leading to more upward-flowing slimes. Typical particle movement velocities were from -0.5 to 1.0 mm/s regardless of the electrolyte and anode composition, and regardless of the operating temperature (25 °C & 60 °C) for small particles (<0.5 mm). The results also support previous findings that increasing the nickel concentration of the electrolyte leads to a more porous anode slime layer on the anode.
2
Content available Electrorefining of High Carbon Ferromanganese in Molten Salts to Produce Pure Ferromanganese
Xiao S.J., Liu W., Gao L., Zhang J.
Archives of Metallurgy and Materials
|
2017
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Vol. 62, iss. 3
1505--1509
EN
High carbon ferromanganese is used as a starting material to prepare pure ferromanganese by electrorefining in molten salts. High carbon ferromanganese was applied as the anode, molybdenum was the cathode and Ag/AgCl was the reference electrode. The anodic dissolution was investigated by linear polarization in molten NaCl-KCl system. Then potentiostatic electrolysis was carried out to produce pure ferromanganese from high carbon ferromanganese. The cathodic product was determined to be a mixture of manganese and iron by x-ray diffraction (XRD). The content of carbon in the product was analyzed by carbon and sulfur analyzer. The post-electrolysis anode was characterized by scanning electron microscope (SEM). The mechanism of the anode dissolution and the distribution of the main impurity of carbon and silicon after electrolysis were discussed.
3
Content available Development of characterization methods for adherent anode slimes in copper electrorefining
Kiviluoma M., Aaltonen M., Aromaa J., Lundstrom M., Forsen O.
Physicochemical Problems of Mineral Processing
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2016
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Vol. 52, iss. 1
295--302
EN
Adherent anode slimes can cause anode passivation in copper electrorefining and lower the efficiency of copper electrorefining. Declining concentrate grades cause larger impurity levels in anodes, thus creating larger quantities of slimes in the refining process. In order to investigate the characterization methods for adherent anode slimes in copper electrorefining, experiments were conducted for the Boliden Harjavalta Pori refinery material. Methods such as particle size determination, chemical (ICP) analysis, settling rate determination, XRD, SEM-SE, SEM-BSE and SEM-EDS were applied. In addition, adherent anode slime samples were compared to optical micrograph and SEM-BSE images of respective anode copper samples. It was shown that SEM-EDS and SEM-BSE provided precise information about phases formed during electrorefining. The settling rate and particle size had a correlation only with a copper content of anode slime. The main phases in the anode slime were copper and lead sulphates as well as copper-silver selenides. NiO was shown to be the major Ni-bearing phase in the adherent slime. Nickel, tellurium and lead had the strongest, whereas arsenic, selenium and antimony had the weakest tendency to report to the anode slime.
4
Content available The perspective of solar and wind energy utilisation in the copper electrorefinement
Głąb T., Jurasz J., Boratyński J.
Ekonomia i Środowisko
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2016
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nr 4
179--193
PL
Odnawialne źródła energii (OZE) pozwalają na wykorzystanie energii promieniowania elektromagnetycznego Słońca w formie bezpośredniej lub poprzez produkty fotosyntezy, energię kinetyczną wiatru, wody itd. W przypadku fotosyntezy, której akumulowana energia jest później pośrednio wykorzystywana w biogazowniach oraz w innych systemach OZE trzeba mieć świadomość niskiej 3–6% wydajności tego procesu. Proponujemy rozważenie zastosowań uwzględniających ograniczenia wynikające z natury OZE w technologiach akceptujących te uwarunkowania. Rozważania opieramy na przykładzie energochłonnego procesu elektrorafinacji miedzi, w którym zużywane jest 300 400 kWh (1,08 1,44 GJ) energii elektrycznej na wydzielenie tony (103 kg) miedzi. Zapewnienie ciągłości procesu można osiągnąć poprzez nowe rozwiązania technologiczne lub w najgorszym przypadku przez wspomaganie energią ze źródeł konwencjonalnych. Nie można wykluczyć, że efektem tych działań będą rozsiane po całym kraju niewielkie instalacje rafinujące miedź, spełniające wymogi środowiskowe i sprzężone z nimi wytwórnie specjalistycznych stopów miedzi. Podejście nie powinno być ograniczone do elektrorafinacji miedzi. Przy źródłach OZE można będzie lokować inne technologie, a nowe rozwiązanie staną się inspiracją do multidyscyplinarnych innowacji.
5
Content available Copper deposition on stainless steel sheets in copper nitrate solution
Kekki A., Aromaa J., Forsen O.
Physicochemical Problems of Mineral Processing
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2015
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Vol. 51, iss. 1
247--256
EN
The aim of this study was to examine factors that influence copper nitrate based electrorefining of copper and to search the best process parameters for high-purity copper deposition on AISI 316L steel blanks. Considering impurities, the most important goal was to minimize sulfur content in a copper cathode. The effect of Cu2+ concentration, current density, temperature and pH were studied. The best parameters for the best copper purity were sorted out. The most important factors for quality copper deposition are sufficiently low Cu2+ concentration, low current density, right zone and careful control of pH. Active nitrate ion reduction reactions catalyzed by copper ions are suggested to affect detrimentally both copper deposition current efficiency and purity. Furthermore, nitrate ion reactions seem to elevate an electrolyte pH so that the deposition appears to be dark brow copper oxide. The 6N purity for copper was not reached with this cell construction and it felled behind about 7 ppm (99.9993% Cu). Both, sulfur and silver concentration were slightly above 1 - 2 ppm. To minimize the impurities, electrolyte circulation and filtration are needed. Also, either a separate silver cementation cell or cementation membrane is needed.
6
Content available A method of proppant pack permeability assessment
Lutynski M. A.
Physicochemical Problems of Mineral Processing
|
2015
|
Vol. 51, iss. 1
325--334
EN
Hydraulic fracturing methods used for low permeability reservoirs such as shale gas or tight gas require the use of proppants. The current standard used for proppant assessment does not take into account its interaction with the rock and the embedment effect. In this paper a new method of proppant pack permeability assessment is proposed where proppant is placed into a rock sample with induced fracture. Three types of proppant were assessed to verify the method i.e. offshore sand, onshore sand and ceramic proppant. The rock sample was a Tumlin sandstone. As the flowing medium supercritical carbon dioxide was used. Tests were performed with 300-500 μm size proppants at flowing pressure of 3 MPa and confining pressure of 5 MPa. Additional test was conducted with 1–2 mm sand proppant at two confining pressure, i.e. 5 MPa and 16 MPa. Proppant were characterized in accordance with the Krumbein/Sloss diagram. Similar values of permeability for the proppant concentration of 0.5 kg/m2 were obtained ranging from 2.3 to 3.3 D although the highest permeability was achieved with Baltic sand proppant and ceramic proppant. For the larger size of proppant (1 – 2 mm) the initial permeability with confining pressure of 5 MPa was initially larger but when the confining pressure was increased it declined by 37%. This proves that in the proposed method we can observe changes in the permeability of the fracture with change in confining pressure apply subjected to the sample.
7
Content available Study On The Electro-Refining Of Tin In Acid Solution From Electronic Waste
Son S. H., Park S. C., Kim J. H., Kim Y. H., Lee M. S., Ahn J.-W.
Archives of Metallurgy and Materials
|
2015
|
Vol. 60, iss. 2B
1217--1220
EN
The tin metal could be retractable from wasted tin scrap, sludge, and wasted electroplated solution hydrometallurgical treatment, and purification process. In order to be used as resource of electronic devices, the retracted crude metal should be purified to the extent of higher than 99.9%. In this study, tin electro-refining process was performed to purify the casted tin crude metal at various experimental conditions: at the current density of 3, 5A/dm2, and in various electrolytes such as hydrochloric acid, sulfuric acid and methansulfonic acid. Additional experiment was conducted using Rotating Disk Electrode (RDE) in order to investigate the rate determining step of tin electro-refining process. The current efficiency, 65.6%, was achievable at the condition of current density, 5A/dm2, and in the electrolyte of Hydrochloric acid. During tin electro-refining process, impurity dissolved from tin crude metal into the electrolyte was analyzed using Inductively Coupled Plasma Optical Emission Spectrometer (ICP-OES), and the result showed the concentration of impurity metal gradually increased. Quantitative analysis on casted tin crude metal showed that it consists of tin with 93.9 wt.% and several impurity metals of Ag, Bi, Pb, Cu, and etc. After tin electro-refining process, the purity of tin increased up to 99.985 wt.%.
8
Content available Morphology Change Of Si Deposit In Molten Salt Electrorefining
Ryu H. Y., Kwon S. C., Han M. H., An Y. S., Lee J. S., Lee J. H.
Archives of Metallurgy and Materials
|
2015
|
Vol. 60, iss. 2B
1491--1497
EN
The effects of processing parameters on the morphology change in a Si deposit recovered by means of molten salt electrorefining are evaluated using electrochemical techniques such as cyclic voltammetry and chronopotentiometry at 800°C. It was found that concentration of K2SiF6 and current density were important parameters in determining deposit size. Higher concentrations of K2SiF6 were effective in coarsening the silicon deposit and decreasing the cell potential. Silicon nanofiber was recovered at 5 wt% of K2SiF6 whereas dense particles were prepared at 30 and 50 wt% of K2SiF6. The morphology of the Si deposit was determined by the concentration of Si in the electrolyte which is related to the formation of crystal and growth of Si. The formation mechanism of the Si deposit was interpreted by using high resolution TEM as well as electrochemical properties.
9
Content available Optimizing of Work Arc Furnace to Decopperisation of Flash Slag
Bydałek A. W., Biernat S., Wołczyński W., Bydałek A.
Archives of Foundry Engineering
|
2015
|
Vol. 15, iss. 3
21--24
EN
Discusses an attempt to optimize the operation of an electric furnace slag to be decopperisation suspension of the internal recycling process for the production of copper. The paper presents a new method to recover copper from metallurgical slags in arc-resistance electric furnace. It involves the use of alternating current for a first period reduction, constant or pulsed DC in the final stage of processing. Even distribution of the electric field density in the final phase of melting caused to achieve an extremely low content of metallic copper in the slag phase. They achieved by including the economic effects by reducing the time reduction.
10
Stan i kierunki rozwoju elektrorafinacji miedzi w świecie
Hanke M., Baranek W., Kopyto D., Kwarciński M.
Rudy i Metale Nieżelazne
|
2011
|
R. 56, nr 4
222-230
PL
W artykule omówiono stan dzisiejszej elektrorafinacji miedzi. Dokonano także przeglądu literatury dotyczącej rozwoju elektrorafinacji miedzi. Stwierdzono, że głównym czynnikiem warunkującym rozwój tej dziedziny przemysłu jest dążenie do uzyskiwania coraz lepszej jakościowo i coraz czystszej miedzi elektrolitycznej, jednocześnie obniżając koszty oraz zwiększając intensywność procesu rafinacji. Wymagania te realizowane są między innymi poprzez optymalizację parametrów technologicznych procesu oraz doskonalenie metod jego kontroli, zmniejszanie odległości pomiędzy elektrodami w wannach elektrolitycznych, lepsze wykorzystanie objętości wanny poprzez zwiększenie liczby elektrod w wannach, zwiększanie gęstości prądu, polepszanie wydajności prądowej procesu rafinacji, zmniejszenie pracochłonności, a więc mechanizacji i automatyzacji czynności produkcyjnych oraz poprawę kontroli procesu. Wszystkie wymienione zabiegi są możliwe dzięki wprowadzaniu szeregu usprawnień istniejących rozwiązań, stosowanych w praktyce rafinacyjnej miedzi, a także dzięki wprowadzaniu zupełnie nowych metod otrzymywania miedzi katodowej.
EN
In this paper the status of currently used copper electrorefining process and also new trends in copper electrorefining are discussed. It was found out that the main trend which indicates progress in this field of industry is to obtain increasingly better quality of cathodic copper and at the same time to reduce costs and increase intensity of the refining process. These requirements are achieved by improving and optimizing the process and its control by means of: reducing man power, therefore increasing mechanization and automation of the process production operations and process control, reducing the distance between the electrodes in the electrolytic cell, more efficient use of electrolytic cell volume by increasing the number of the electrodes in the cell, increasing the current density, improving the process current efficiency. All these operations are possible due to implementation of a series of improvements to existing solutions used in copper electrorefining and due to introduction of brand new solutions. These are also discussed in this paper.
11
Content available Główne przyczyny uszkodzeń wanien elektrolitycznych stosowanych w hutnictwie miedzi
Marcinowski J.
Przegląd Budowlany
|
2010
|
R. 81, nr 5
124-127
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