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.
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Nickel matrix composites reinforced with T15 high-speed steel (HSS) particles were prepared using powder metallurgy. A systematic investigation was conducted into the effects of the sintering temperature and T15 HSS particle content on the microstructure and properties of the composites. The results indicate that the grain size of the nickel in the composites was effectively refined by the addition of T15 HSS particles in comparison to the pure sintered nickel. It was also observed that the T15 HSS particles, after sintering at all the used temperatures (850, 900 or 950 °C), were diffusion-bonded to the nickel matrix. There were two distinct layers between the reinforced particles and the nickel matrix: the solid solution of elements in nickel and the FeNi3 intermetallic compound, whose thickness slowly grows with the increase in sintering temperature. Also, as the sintering temperature was incremented, the relative density and hardness of the composites gradually rose. When sintered at 950 °C, the Ni+20 wt.%T15 composite achieved a maximum hardness of 135 HB, which was about 52 % higher than that of the pure sintered nickel. The introduction of an increasing amount of T15 HSS particles combined with sintering resulted in a rise in the yield strength of the sintered composites. At all the investigated temperatures, as the T15 HSS particle content was increased, the compressive strength of the composites also gradually grew. Nonetheless, as the sintering temperature was raised from 850 to 950 °C, the compressive strength of the composites initially increased and then decreased. The composite containing 20 wt.%T15 HSS particles sintered at 900 °C achieved the highest compressive strength of 445 MPa, which was about 50 % higher than that of the pure sintered nickel. Additionally, the primary contributions of strengthening mechanisms such as load transfer, grain refinement and thermal expansion mismatch to the mechanical properties of the Ni+T15 HSS composites were analyzed.
he scientific and industrial communities now consider surface modification of steel-based alloys to be essential. One effective method of altering these alloys' surfaces is tungsten inert gas (TIG) cladding.The purpose of this study is to investigate how the surface characteristics of austenitic stainless steel substrates are affected by TIG-deposited composite coatings made of tungsten carbide and nickel (WC-Ni). The study also intends to investigate the influence of the WC-Ni composite coatings' travel speed, and as a result, the heat input usually has significant effects on the microstructure. The coating layers were deposited at different travel speeds (67, 107, and 122 mm/min) using pre-placed composite pastes that were 1 mm thick and contained the same weight percentage of WC (65). The clad layers showed a variety of microstructures in optical and scanning electron microscopy, primarily nickel solid solution dendrites with WC particles scattered throughout the matrix. The dendrites at various locations across the clad layers were few or dense, finer or coarser, equiaxial or columnar, densely or less densely branched, depending on the cooling rates and the density of WC in the composite. Energy dispersive spectroscopy demonstrated that the Fe element that was transferred from the substrate material to the molten pool was primarily concentrated in the matrix, not the dendrites, while the dendrite locations and orientations were amply demonstrated by the distribution of the W element.
The article is devoted to the experimental determination of thermokinetic parameters of oil sludge thermal degradation using the model-free Ozawa-Flynn-Wall method in the presence of a nanocatalyst (nickel, cobalt and iron-supported microsilicate) by calculating Arrhenius kinetic parameters (activation energy and pre-exponential factor). The phase composition of the reflex microsilicate was established – 4.12; 2.51 Å – SiO2, nickel-supported microsilicate reflexes: 2.09; 1.48 Å – NiO, reflexes: 4.25 Å – SiO2 and acid numbers of microsilicate – 64 μmol/g of prepared nanocatalysts. Using the method of Brunauer, Emmett and Teller, the specific surface area of the microsilicate was established – 18.3 ± 0.3 m2 /g, the microsilicate with nickel applied – 20.9 ± 0.2 m2 /g and the adsorption isotherm of the prepared nanocatalysts (microsilicate with nickel, cobalt and iron). Thermokinetic parameters of thermal decomposition of oil sludge without a catalyst and with a catalyst at an increment of 0.9 are 99.0 and 93.3 kJ/mol nickel-supported microsilicate, 51.9 kJ/mol cobalt-supported microsilicate, 111.3 kJ/mol iron-supported microsilicate and non-metal-supported microsilicate 173.7 kJ/mol, respectively. The study of the kinetic parameters of pyrolysis of oil sludge using various catalysts makes it possible to assess their influence on the process of decomposition of organic components. The results of the experiments showed that the use of catalysts significantly affects the destruction of oil sludge. Dynamic thermal analysis at different heating rates studied the dynamics of oil sludge decomposition. The study of the effect of catalysts on the kinetic parameters of oil sludge pyrolysis is an important step in the development of new methods for the disposal of petroleum products and the reduction of their negative impact on the environment. The obtained experimental data on thermal degradation kinetics of oil sludge will find application in designing a reactor for the process of destructive hydrogenation of heavy hydrocarbon raw materials.
Nikiel (Ni) jest metalem o charakterystycznym połysku. Znalazł zastosowanie do produkcji stopów, w galwanizacji, produkcji baterii, protez, pigmentów, w przemyśle ceramicznym i komputerowym. Skutki narażenia ludzi na nikiel i jego związki w warunkach zawodowych obejmują głównie wpływ na układ oddechowy (w tym ryzyko wystąpienia chorób nowotworowych płuc i jamy nosowej, zwłóknienie i pylicę płuc, astmę oskrzelową) oraz działanie uczulające na skórę i układ oddechowy. Szkodliwy wpływ niklu i jego związków na układ oddechowy potwierdzają wyniki badań doświadczalnych na zwierzętach. Długotrwałe narażenie na nikiel i jego związki powodowało również osłabienie układu odpornościowego oraz skutki nefro- i hepatotoksyczne. Rozpuszczalne sole niklu nie wywoływały mutacji w komórkach bakterii, ale genotoksyczność niklu i jego związków potwierdzono w badaniach z użyciem komórek eukariotycznych ssaków, przy czym jedynie przy wysokich stężeniach niklu. Nikiel i jego związki mogą przenikać przez łożysko oraz do mleka matki. Działanie rakotwórcze na układ oddechowy po narażeniu inhalacyjnym było także wykazane w badaniach na szczurach, głównie dla siarczku niklu oraz tlenku niklu. Zaproponowano przyjęcie wartości wiążących dla związków niklu ujętych w dyrektywie Parlamentu Europejskiego i Rady (UE) 2022/431 z dnia 9 marca 2022 r., zmieniającej dyrektywę 2004/37/WE, jako wartości NDS: 0,01 mg Ni/m³ (frakcja respirabilna), 0,05 mg Ni/m³ (frakcja wdychalna). Zaproponowano przyjęcie do 17 stycznia 2025 r. włącznie okresu przejściowego, podczas którego obowiązywać będzie wartość NDS wynosząca 0,1 mg/m³ w odniesieniu do frakcji wdychalnej związków niklu. Proponuje się oznakować jako substancje o działaniu: uczulającym, rakotwórczym kat. 1A – związki niklu (Carc. 1A), rakotwórczym kat. 2 – nikiel metaliczny (Carc. 2), szkodliwym na rozrodczość.
EN
Nickel (Ni) is a metal with a distinctive luster, and has found applications in alloying, electroplating, battery manufacturing, prosthetics, pigments, ceramics and computer industries. The effects of human exposure to nickel and its compounds under occupational conditions mainly include effects on the respiratory system (including the risk of cancer of the lungs and nasal cavity, fibrosis and pneumoconiosis, bronchial asthma) and sensitization of the skin and respiratory system. The harmful effects of nickel and its compounds on the respiratory system are confirmed by the results of experimental studies on animals. Long-term exposure to nickel and its compounds also caused immune system impairment and nephro- and hepatotoxic effects. Soluble nickel salts did not induce mutations in bacterial cells, but the genotoxicity of nickel and its compounds has been confirmed in studies using mammalian eukaryotic cells, with only high nickel concentrations. Nickel and its compounds can cross the placenta and into breast milk. Respiratory carcinogenic effects after inhalation exposure have also been demonstrated in rat studies, mainly in regard of nickel sulfide and nickel oxide. It has been proposed to adopt the binding values for nickel compounds included in Directive (EU) 2022/431 of the European Parliament and of the Council of March 9, 2022, amending Directive 2004/37/EC, as the NDS values: 0.01 mg Ni/m³ (respirable fraction), 0.05 mg Ni/m³ (inhalable fraction). It is proposed to adopt a transitional period up to and including January 17, 2025, during which an NDS value of 0.1 mg/m³ will apply to the inhalable fraction of nickel compounds. It is proposed to label as substances with the following effects: sensitizer, carcinogen cat. 1A – nickel compounds, Carc. 2 – carcinogenic cat. 2 – nickel metal, reproductive toxicity.
The processing of lower-grade laterites to obtain nickel has increased due to the gradual depletion of higher-grade sulphide ore reserves. However, the extraction from laterites has been limited because conventional technologies imply a considerable expense of energy or reagents. In this document, the effect of thermal pre-treatments on a laterite sample is demonstrated to improve nickel leaching under moderate conditions. The influence of agents such as coke, coal and NaCl in the heat treatment was also studied. With the results it is presumed that part of the nickel occluded in the goethite migrates to the iron oxides surface during the heat treatment; this is why the dissolution of nickel is linked to that of iron. The highest extractions (64.7% nickel) were achieved by combining heat treatment and leaching with 1 M H2SO4 at ambient conditions. Compared to direct leaching of unpretreated laterite, leaching rates for this metal are increased by 26.5%. The chlorinating calcination and the optimization of the studied variables will be favourable to reach higher metallic extractions.
Aloe vera leaves (AVL), a by-product of agricultural waste, have been applied as a biosorbent for reducing Ni(II) ions in aqueous solutions. The biosorption capability of AVL powder was enhanced through chemical treatment with 0.10 M citric acid solution. Fourier-transform infrared (FTIR) spectrophotometer, scanning electron microscope coupled with energy dispersive X-ray (SEM-EDX), pH of point-zero-charge (pHPZC), and pHslurry analyses were used to study the surface, and chemical properties of citric acid-treated Aloe vera leaf powder (CAAVLP). The setting for experiments such as pH solution, CAAVLP dose, initial concentration, and biosorption time was investigated. Maximum Ni(II) ion biosorption capability was determined to be 48.65 mg/g based on the Langmuir model at pH 6, a CAAVLP dose of 0.02 g, initial Ni(II) concentrations of 5 to 50 mg/L and biosorption time of 120 min. The data for the isotherm and kinetics were well matched with the Freundlich and pseudo-second-order models, respectively, with high regression correlation (R2) and low chi-square (χ2) values. The presence of more-COOH groups after treating AVL with citric acid resulted in more Ni(II) ions being able to be removed.
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The elements are present in the environment. Moreover, they are used in pharmacy and the production of new materials used in medical applications. They are often as environmental pollutants. They can accumulate in organisms and induce toxic effects on the cellular level. HepG2, L929 and Caco-2 cell lines were exposed to known concentrations of chromium chloride, iron chloride, nickel chloride, molybdenum trioxide and cobalt chloride (200 or 1000 μ M used alone and in combinations). Concentrations of chromium, iron, nickel, molybdenum and cobalt in the cell lysate and the culture medium were determined by ICP-MS. Moreover, sodium, potassium, calcium and magnesium concentrations were also measured. What is more, cells were observed under light and scanning electron microscope. The dose-dependent increase in the concentration of chromium, iron, nickel, molybdenum and cobalt in all cell lines after incubation with elements was observed. Potassium concentration decreases while sodium calcium and magnesium increase after incubation of cells with of mentioned elements. The incubation of cells with microelements induces cell morphology changes. The presented study shows the crucial role of tested microelements in the induction of cell death as a result of an imbalance of sodium, potassium, calcium and magnesium concentration inside the cell.
Polymer enhanced ultrafiltration (PEUF) technique economically enables separation and/or retention of various heavy metal ions from aqueous solutions for environmental and engineering problems. Polyethylenimine as the water-soluble complexation agent utilized to interact with heavy metal ions of Cd and Ni as cations in ultrafiltration experiments were modeled with protonation data to understand the mechanism. Test runs showed that an enrichment coefficient (the ratio of Cd over Ni in permeate) up to 10 was obtained at pH 4.2 in the temperature range of 20-22oC, whereas full retention of both cations is possible above pH 5.0 and those results are highly compatible with the model developed.
Fractions of Ni, Mn and Fe in the municipal solid waste incineration (MSWI) bottom ash were investigated. Three fractions of studied metals were separated according to the BCR procedure (acid soluble and exchangeable, reducible and oxidizable). Pseudo-total metal content, pH and dry mass in all samples were evaluated. The share of nickel in fractions followed the sequence: F4 (79.0%) > F3 (9.0%) > F1 (7.5%) > F2 (4.5%), for manganese: F4 (60.4%) > F1 (16.8%) > F2 (13.2%) > F3 (9.6%) and for iron: F4 (74.4%) > F2 (12.6%) > F3 (12.5%) > F1 (0.5%). Mobile pool of metals (F1-F3) contained the least of nickel (21.0%) and the most of manganese (39.7%).
The catalytic conversion of a model tar compound, namely: naphthalene contained in a simulated producer gas from wood gasification process was investigated. The sol-gel approach was used to create a mesoporous Cepromoted Ni/alumina catalyst with high surface area. A surface area of 333 m2g was achieved by calcination of the mesoporous catalyst (17 wt% Ni and 2.8 wt% Ce) under air conditions at 1123 K. The catalysts were characterized using the N2 adsorption-desorption, XRD, and SEM techniques, and their promotion effect on producer gas reforming and tar removal was studied under dry, steam, and partial oxidation conditions. The Ni-based catalysts effectively converted naphthalene and increased the proportion of H2 and CO in the reformed gas. Incorporating Ce into the catalyst increased the proportion of H2 and CO in the reformed gas, while lowering the amount of CH4 and CO2. In the absence of oxygen, catalytic reforming of the producer gas resulted in 79.6% naphthalene conversion, whereas catalytic partial oxidation conditions resulted in 99.1% naphthalene conversion.
Due to the increasing problem resulting from environmental pollution with heavy metals, great emphasis is placed on the development of removal methods of these pollutants from the environment. This study presents a literature review on the methods for the removal of nickel ions from aqueous solutions such as sorption, especially using low-cost sorbents which are very popular in 21𝑠𝑡 century, electrochemical processes and membrane techniques. It is often impossible to use a single technique for efficient removal of heavy metals from wastewater as the process depends on many factors, such as wastewater composition, pH, temperature and many others. The aim of this review is to present some selected removal techniques of nickel(II) from wastewater from the point of view of their efficiency and applicability.
The microbiological activity associated with exmining soil remediation can be considered useful to accelerate the contaminant degradation. The use of sulfate-reducing bacteria (SRB) and organic matter exhibits potential in improving ex-nickel mining soil quality. The purpose of this study was to examine the ability of SRB in several organic fertilizers to reduce sulfate and nickel ions, and to increase pH of soil from nickel in mining areas. This study used the bacteria collection of the Soil Laboratory of the Faculty of Agriculture, Universitas Muslim Indonesia. Those were previously isolated from two cultivating pond of milkfish in the Kuri area of Maros Regency, South Sulawesi, Indonesia. The soil samples were collected from ex-mining areas of the Vale Indonesia Enterprise in Soroako, South Sulawesi, Indonesia. Those were mixed with organic fertilizers, generated from sugarcane sludge, manure, and Quickstick (Gliricidia sepium) leaves, each with 50 and 100 g doses. The 5 kg soil samples were put into a pot and mixed evenly with organic fertil- izers. A general linear model (GLM) repeated measures analysis of variance (ANOVA) was adopted to analyze the data. The results of this study indicate that the application of SRB and fertilizer was effective in reducing concentration of sulfate and nickel. Among the three types of organic fertilizers, manure was effective in reducing sulfate and nickel concentrations, while Quickstick fertilizer was the more effective in stabilizing pH level. Fertilizer doses exhibited a significant effect on decreasing sulfate and nickel concentrations, but it exhibited no significant effect on stabilizing pH levels. At 10 days after treatment (DAT), the sulfate concentration decreased from 2,530 ppm to 1,443 ppm in treatment of SRB and manure with dose of 50 g and 1,363 ppm with that of 100 g. At the end of the observation (30 DAT), those were decreased to 1,217 ppm in treatment of SRB and manure with doses of 50 g and 1,167 ppm with that of 100 g. Among the three types of organic fertilizers used, Quickstick demonstrates the more effective reduction rate. At 10 DAT, pH increased in SRB treatment by 7.06 at a concentration of 50 g and 7.01 at a concentration of 50 g. At the end of the observation (30 DAT), the pH became 6.67 at a concentration of 50 g and 6.82 at a concentration of 50 g. The nickel concentration decreased from an origin concentration to 1,950 ppm in treatment of SRB and manure with doses of 50 g and 1,690 ppm with that of 100 g. Thus, the application of manure fertilizer and the addition of SRB is recommended for bioremediation of sulfate and nickel from ex-mining soil.
Nikiel dzięki swoim właściwościom fizykochemicznym jest stosowany do wytwarzania stopów o wysokiej wytrzymałości, odpornych na korozję i temperaturę, o wysokiej rezystancji i kwasoodpornych. Nikiel w postaci drobnego proszku może wywoływać odpowiedź alergiczną w kontakcie ze skórą, udowodniono również właściwości rakotwórcze przy długotrwałym narażeniu na pył niklowy. Zgodnie z proponowaną dyrektywą Parlamentu Europejskiego nr 2020/0262 zaproponowano wartość najwyższego dopuszczalnego stężenia (NDS) w powietrzu na stanowiskach pracy dla frakcji wdychalnej 0,05 mg/m³ , a dla frakcji respirabilnej 0,01 mg/m³ (2020/0262/COD). Celem badań było opracowanie metody oznaczania niklu do oceny narażenia zawodowego w zakresie 1/10 ÷ 2 zaproponowanych wartości NDS. Metoda polega na: pobraniu aerozolu niklu i jego związków zawartych w powietrzu na filtr, mineralizacji filtra w kwasie azotowym(V) i kwasie chlorowodorowym w podwyższonej temperaturze, a następnie oznaczeniu zawartości niklu w próbce z zastosowaniem absorpcyjnej spektrometrii atomowej (AAS) z atomizacją w płomieniu. Metoda oznaczania niklu została przedstawiona w postaci procedury analitycznej, którą zamieszczono w załączniku. Zakres tematyczny artykułu obejmuje zagadnienia zdrowia oraz bezpieczeństwa i higieny środowiska pracy będące przedmiotem badań z zakresu nauk o zdrowiu i inżynierii środowiska.
EN
Nickel due to its physicochemical properties is used to produce high strength, corrosion resistant, temperature resistant, high resistance and acid resistant alloys. Nickel in the form of fine powder can induce an allergic response when in contact with the skin, carcinogenic properties have been proven with long-term exposure to nickel dust. According to the proposed directive of the European Parliament No. 2020/0262, a value of maximum allowable concentration (MAC) in a workplace air in Poland for the inhalable fraction should be at 0.05 mg/m³ and for the respirable fraction at 0.01 mg/m³ (2020/0262/COD). The aim of this study was to develop a method for determining nickel in the range of 1/10 ÷ 2 of the MAC. The method is based on gathering nickel aerosol and its compounds contained in the air on a filter, filter mineralization in nitric acid(V) and hydrochloric acid at elevated temperature then determination of nickel content in the sample using atomic absorption spectrometry (AAS) with flame atomization. The method for the determination of nickel is presented in the form of an analytical procedure, which is included in the appendix. This article discusses the problems of occupational safety and health, which are covered by health sciences and environmental engineering.
Spent Nickel–metal hydride batteries can be sources of valuable metals such as nickel, cobalt, manganese, rare earths and toxic chemicals. The recycling of these materials is necessary from both economic and environmental points of view. In this study the nickel is leached in acid solution followed by precipitation and thermal decomposition or by cementation. The affecting parameters such as acid type and concentration, time, temperature and solid/liquid ratio were investigated. The maximum of leached nickel could be obtained in 3M sulfuric acid at 65°C for 60 min with solid-to-liquid ratio of 30 g L-1. The liquid film is a more suitable model for demonstrating the kinetics of the nickel leaching. Thermal decomposition of the precipitated nickel dimethyl-glyoxime was employed in preparation of nickel oxide. Nickel was separated from aqueous solution by cementation on zinc. The cementation process follows pseudo first-order kinetics and diffusion controlling steps. The yield was 91% of the original nickel content.
In this work, nickel adsorption onto low Jordanian zeolite dose is being investigated. Natural zeolite doses were stirred continuously with nickel solutions in batch reactors at 180 RPM for 24 hours, where the temperature was set to 20°C. The pH was initially 4.5 and reached 5.2 at equilibrium. The removal efficiency of nickel reaches maximum value when the initial nickel concentration is around 1 ppm and then tends to decrease when the initial nickel concentration increases above 1 ppm. The optimal nickel removal reaches 65% when the initial nickel concentration is 1 ppm and the zeolite dose is 26 mg∙dm–3. This study investigates the behaviour of nickel removal and modelling isotherms below and above this critical peak point. At this level of zeolite dose, the adsorption does not follow either Freundlich or Langmuir isotherms, but rather, it follows Freundlich for the data plot just below the peak point with the highest coefficient of determination (R2) equals (0.98) when the zeolite dose is (26 mg∙dm–3), whereas it follows Langmuir for the data plot just above the peak point with the highest coefficient of determination (R2) equals (0.99) when the zeolite dose is (10 mg∙dm–3). These findings clarify the theory behind each isotherm and can be used to find new information for efficient treatment techniques.
Pollution of the soil by different types of heavy metals is one of the most important problems of the environment. The present study used an electro-kinetic remediation, which is one of the important advanced techniques for the removal nickel from contaminated sandy soil. The study includes many experiments with different pH electrode purging solutions (distilled water at pH of 3, 5 and 7). Anionic surfactant (sodium dioctyl sulfosuccinate, AOT) was used for washing soil as surfactant-enhanced remediation. Bio remedies banana peels (BP) were utilized as eco-friendly, low cost and adsorbent materials to avoid reverse osmosis that effects on the removal process. The results indicated that the greatest removal efficiency (65.2%) was achieved at the pH of purging solution (3) in comparison with pH of (5 and 7). This means that when the pH of the purging solution decreases, the removal efficiency increases. Using AOT as a soil-washing solution increased nickel dissolution and desorption from surface of the soil. Then, the AOT micelles containing nickel easily migrated to the cathode chamber by flow of the electro osmotic; thus, the removal efficiency increased (74.8%). In conclusion, the use of AOT is effective in enhancing nickel removal through the electro kinetic remediation. Bio remedies using banana peels is considered as a successful adsorbent material to avoid the reverse osmosis flow, this will give a new thought for the application these products as adsorption medium.
As the amount of high-capacity secondary battery waste gradually increased, waste secondary batteries for industry (high-speed train & HEV) were recycled and materialization studies were carried out. The precipitation experiment was carried out with various conditions in the synthesis of LiNi0.6Co0.2Mn0.2O2 material using a Taylor reactor. The raw material used in this study was a leaching solution generated from waste nickel-based batteries. The nickel-cobalt-manganese (NCM) precursor was prepared by the Taylor reaction process. Material analysis indicated that spherical powder was formed, and the particle size of the precursor was decreased as the reaction speed was increased during the preparation of the NCM. The spherical NCM powder having a particle size of 10 μm was synthesized using reaction conditions, stirring speed of 1000 rpm for 24 hours. The NCM precursor prepared by the Taylor reaction was synthesized as a cathode material for the LIB, and then a coin-cell was manufactured to perform the capacity evaluation.
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Process baths used for electropolishing and pickling of stainless steel have become increasingly contaminated with heavy metal ions over time. There is still lack of research on the neutralization of this type of technological wastewater with high concentrations of metal ions and containing complexing compounds, which significantly hinders their effective treatment. The aim of this paper is to study how the selected methods of heavy metals removal will affect the quality of the treated, industrial post-galvanic sewage from pickling and electropolishing of chromium-nickel steel on a laboratory and technical scale. The research used sodium sulphide or a decomplexing agent based on organic sulphur to neutralize wastewater containing triethanolamine or glycerol. Treatment of electropolishing wastewater poses a challenge. Nevertheless, wastewater with glycerol is easier to neutralize than those containing triethanolamine. In the industrial scale the use of a decomplexing agent is necessary to achieve the required nickel values in the wastewater after treatment below 1 ppm. Even in the case of high concentrations of nickel ions in raw wastewater, the neutralization process of the wastewater originating only from pickling alone was effective. The search for effective methods of neutralization of mixed wastewater is especially important in industrial conditions, where it is not always possible to completely separate these two types of sewage. The paper also presents the results of the composition of post-neutralization sludge, which may be useful in planning further management and disposal of this type of waste.
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The article presents the results of the preliminary research of tribological properties of flame sprayed nickel and aluminum coatings reinforced with carbon nanotubes made on the structural steel S235J0 substrate. The carbon material – carbon nanotubes Nanocyl NC 7000 (0.5 wt.% and 1 wt.%) was used for structural reinforcement. The properties evaluation was made by the use of optical microscopy, scanning electron microscopy, Raman spectroscopy, microhardness measurements, and by means of abrasion and erosion resistance laboratory tests. The obtained results were compared with pure nickel powder coatings 2N5 (Ni 99.5%) and with pure aluminum powder coatings (EN AW 1000 series). It was proved that the flame spraying of nickel and aluminum coatings reinforced with particles carbonaceous material can be an effective alternative for other more advanced surfacing technology. The preliminary test results will be successively extended by further experiments to contribute in the near future to develop innovative technologies, that can be implemented in the aviation industry and the automotive. The presented research is a continuation of the work previously published.
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