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EN
This work presents studies on the recovery of platinum group metals (PGM), especially platinum and rhodium, from spent automotive converters using hydrometallurgical techniques such as leaching and liquid-liquid extraction. The XRD analysis confirmed the presence of indialite – the high temperature hexagonal form of cordierite (the main catalyst building material) in the solid samples. The influence of time and temperature on the leaching of PGM from spent automotive converters was investigated. The largest amounts of Pt(IV) and Rh(III) were leached with freshly prepared aqua regia and a mixture of HCl, HSO4 , and H2O2. Further, liquid-liquid extraction with quaternary phosphonium ionic liquid (Cyphos IL 101) was applied to recover PGM from the leach solutions (after leaching with a mixture of HCl, H2SO4, and H2 O2) and to separate Pt(IV) from Rh(III).
EN
Copper oxide ore was pre-concentrated using near infrared sensor-based method and classified as product, middling and waste. The product and middling fractions were leached with ammonium chloride reagent. The effect of temperature, ammonium chloride concentration, solid- liquid ratio, stirring speed and particle size experimental variables were investigated. Mineralogical and chemical analysis of the ore fractions indicated that copper content was in accordance with the preconcentration strategy, with the product having a higher concentration than the middling and waste. The rate of copper extraction was found to be higher in the product than in the middling sample which further supports the near infrared classification, QEMSCAN®, X-ray diffraction, SEM mineralogical and X-ray florescence and Inductively coupled plasma Mass spectrometry chemical data. It was revealed that the leaching rate increases with increasing ammonium chloride concentration, temperature and decreasing ore particle size, stirring speed and solid-liquid ratio. Analysis of the experimental data by shrinking core model indicated that the dissolution kinetics follow the heterogeneous reaction model for the chemical control mechanism where the activation energies of 45.9 kJ/mol and 47.5 kJ/mol for product and middling fractions respectively were obtained. Characterization of the residue obtained at optimum leaching condition with X-ray diffraction suggests that copper was selectively leached when compared to the profile of the raw ore. The trace levels of metals associated with abundant X-ray diffraction profiles of residue found in the leachate further confirm the selective leaching process.
EN
Leaching process of Jiroft refractory manganese ore was investigated. The effects of operating parameters such as liquid to solid ratio, pulp temperature, sulfuric acid concentration, and oxalic acid concentration were studied and the optimization was done through the response surface methodology (RSM) based on central composite design (CCD) model. The recoveries of Mn, Fe and Si were selected as response of design. The optimum condition was determined by ANOVA, indicating that the liquid to solid ratio, oxalic acid concentration and pulp temperature for Mn recovery and liquid to solid ratio, pulp temperature and sulfuric acid concentration for Fe recovery and liquid to solid ratio for Si recovery were the most effective parameters, respectively. Under the optimum conditions of liquid to solid ratio= 11.8%, pulp temperature= 70 ℃ sulfuric acid concentration= 40 g/L and oxalic acid concentration= 35 g/L, 71.1%, 4.67% and 0.6% of Mn, Fe and Si were recovered, respectively.
EN
The leaching with acids is one of many methods used for recovery of valuable components from industrial wastes. The processing and neutralization of this type of waste is very difficult due to toxic properties. This work shows the results of aluminum leaching from industrial black dross with oxalic acid depending on temperature, acid concentration, effect of liquid to solid ratio (L/S) and time process. The oxalic acid has not been used so far for processing of aluminum black dross. The main purpose of this work was to determine the optimal conditions of this process. The results show that the maximum leaching efficiency of aluminum (75.2 %) was obtained with a liquid to solid ratio of 20:1 using 0.5 mol·dm-3 oxalic acid at 75 °C for 3 h.
EN
The aim of the work was to draw attention to the usefulness of the alkaline thermal activation process with sodium hydroxide in the process of rare earth metal leaching (REE), from fly ash with hydrochloric acid and nitric acid(V). The work is a part of the authors’ own research aimed at optimizing the REE recovery process coming from fly ash from hard coal combustion. The article contains an assessment of the possibility of leaching rare earth metals (REE) from fly ash originating from the combustion of hard coal in one of the Polish power plants. The process was carried out for various samples consisting of fly ash and sodium hydroxide and for different temperatures and reaction times. The process was carried out for samples consisting of fly ash and sodium hydroxide containing respectively 10, 20 and 30% on NaOH by weight in relation to the weight of fly ash. Homogenization of these mixtures was carried out wet, and then they were baked at 408K, 433K and 473K, for a period of three hours. The mixture thus obtained was ground to a particle size of less than 0.1 mm and washed with hot water to remove excessive NaOH. The solid post-reaction residue was digested in concentrated HCl at 373K for 1 hour at a weight ratio fs/fc of 1:10. The results of chemical analysis and scanning microscopic analysis along with EDS analysis and X-ray analysis were used to characterize the physicochemical properties of the tested material. The results indicated that REE recovery from fly ash strictly depends on heat treatment temperature with NaOH, and an increase in REE recovery from alkaline-activated fly ash along with increasing the amount of NaOH in relation to fly ash mass.
PL
Celem pracy było zwrócenie uwagi na przydatność alkalicznego procesu aktywacji termicznej wodorotlenkiem sodu w procesie ługowania metali ziem rzadkich (REE) z popiołu lotnego z kwasem chlorowodorowym i azotowym (V). Praca jest częścią badań własnych autorów mających na celu optymalizację procesu odzyskiwania REE z popiołów lotnych ze spalania węgla kamiennego. Artykuł zawiera ocenę możliwości ługowania metali ziem rzadkich (REE) z popiołów lotnych pochodzących ze spalania węgla kamiennego w jednej z polskich elektrowni. Proces przeprowadzono dla próbek składających się z popiołu i wodorotlenku sodu zawierającego odpowiednio 10, 20 i 30% wagowych NaOH w stosunku do masy popiołu. Homogenizację tych mieszanin przeprowadzono na mokro, a następnie spiekano je w temperaturze 408K, 433K i 473K przez okres trzech godzin. Tak otrzymaną mieszaninę zmielono do wielkości cząstek mniejszej niż 0,1 mm, a następnie przemyto gorącą wodą w celu usunięcia nadmiaru NaOH. Stałą pozostałość poreakcyjną trawiono stężonym HCl w temperaturze 373K przez 1 godzinę, przy stosunku wagowym fs/fc wynoszącym 1:10. Wyniki analizy chemicznej i skaningowej analizy mikroskopowej wraz z analizą EDS i analizą rentgenowską wykorzystano do scharakteryzowania właściwości fizykochemicznych badanego materiału. Otrzymane wyniki wskazują, że odzysk REE z popiołu zależy ściśle od temperatury obróbki cieplnej za pomocą NaOH, oraz że odzysk REE z popiołu aktywowanego alkalicznie rośnie wraz ze wzrostem ilości NaOH w stosunku do masy popiołu.
EN
In this study, laboratory-scale experiments were carried out to investigate the effects of microwave-assisted alkaline leaching on the treatment of electric arc furnace dusts to recover zinc and lead. Microwave treatment is a new innovative technology in waste treatment and now is an attractive advanced inter-disciplinary field and also environmental friendly. The highest zinc extraction, 50.3% in 60 minutes using 5 M NaOH at 750 W and L:S ratio 20, and lead extraction up to 92.84% was achieved in these same conditions but in 30 minutes. Compared with conventional leaching, the top extraction rate using MW-assisted leaching was higher by 16% (Zn) and 26% (Pb). Zinc presents in the flue dust in the form of franklinite (ZnFe2 O4 ), its leaching in sodium hydroxide does not occur under the examined conditions, because it is enclosed in a matrix of iron.
EN
Industrial steelmaking (EAF) flue dust was characterized in terms of chemical and phase compositions, leaching behaviour in 20% sulphuric acid solution as well as leaching thermal effect. Waste product contained about 43% Zn, 27% Fe, 19% O, about 3% Pb and Mn and lesser amounts of other elements (Ca, Si, Mo, etc.). It consisted mainly of oxide-type compounds of iron and zinc. Dissolution of metals (Zn, Fe, Mn) from the dust was determined in a dependence of solid to liquid ratio (50-200 g/L), temperature (20-80°C) and leaching time (up to 120 min). The best result of 60% zinc recovery was obtained for 50 g dust/L and a temperature of 80°C. Leaching of the material was an exothermic process with a reaction heat of about –318 kJ/kg. Precipitation purification of the solution was realized using various ratios of H2 O2 to NH3aq . A product of this stage was hydrated iron(III) oxide. Final solution was used for zinc electrowinning. Despite that pure zinc was obtained the highest cathodic current efficiency was only 40%.
PL
Celem badań jest określenie zawartości rtęci w węglach kamiennych, losowo pobranych z GZW oraz w produktach ubocznych wydobycia węgla (odpady wydobywcze świeże), czyli kruszywach i mułach węgla kamiennego, a także odpadach górniczych ze zwałowiska Siersza (odpady zwietrzałe). Do analizy przeznaczono 34 próbki. Określono zawartość całkowitą rtęci oraz wielkość wymywania rtęci z próbek stałych. Obliczono ponadto udział formy wymywalnej w całkowitej zawartości pierwiastka, czyli poziom uwalniania rtęci z materiału (poziom wymycia). Badania wielkości wymywania rtęci określono metodą statyczną z zastosowaniem testu wymywalności 1:10. Najwyższą możliwością wymywania rtęci charakteryzują się odpady zwietrzałe ze zwałowiska Siersza i nieco niższą analizowane węgle kamienne z Górnośląskiego Z agłębia Węglowego (GZW). Dla próbek węgla kamiennego zawartość rtęci całkowitej kształtuje się w granicach 0,0275–0,1236 mg/kg. Natomiast wielkość wymywania rtęci z próbek węgli kształtuje się na poziomie 0,0008−0,0077 mg/kg. Odpady świeże typu kruszywa charakteryzują się wyższą zawartością rtęci całkowitej we frakcji najdrobniejszej 0-6 mm w granicach 0,1377−0,6107 mg/kg i zdecydowanie niższą we frakcji 80–120 mm w granicach 0,0508−0,1274 mg/kg. Wielkość wymywania jest porównywalna w obydwu frakcjach i kształtuje się na poziomie 0,0008−0,0057 mg/kg. Muły węglowe charakteryzują się zawartością rtęci całkowitej na poziomie 0,0937−0,2047 mg/kg. Obserwuje się także niskie wartości wymywania na poziomie 0,0014−0,0074 mg/kg. Odpady górnicze zwietrzałe charakteryzują się zawartością całkowitą rtęci w granicach 0,0622−0,2987 mg/kg. Obserwuje się jednak zdecydowanie wyższe wartości wymywania z odpadów zwietrzałych niż z odpadów wydobywczych świeżych. Wielkość ta kształtuje się na poziomie 0,0058−0,0165 mg/kg. W węglach kamiennych pobranych z GZW poziom wymycia kształtuje się na średnim poziomie 4,7%. Odpady wydobywcze charakteryzują się dużą zmiennością udziału formy wymywalnej rtęci a różnice wynikają z czasu sezonowania próbek. Odpady czy materiały uboczne produkcji węgla kamiennego typu kruszywa oraz muły węglowe wykazują udział formy wymywalnej rtęci na średnim poziomie 1,7%. W odpadach zwietrzałych udział formy wymywalnej zdecydowanie wzrasta do 7,3%. Charakterystyka wymywania jest zróżnicowana dla różnych grup badanego materiału. Podstawowe znaczenie a wykazane w pracy, mają czynniki takie jak rodzaj i pochodzenie próbek, ich skład granulometryczny oraz czas sezonowania materiału.
EN
The aim of the study is to determine the mercury content in hard coal, randomly taken from the U SCB and in by-products of hard coal mining (fresh mining waste), i.e. aggregates (gangue) and hard coal sludge and mining waste from the Siersza dump (weathered waste). The 34 samples were intended for analysis. The total mercury content and the amount of mercury leaching from solid samples was determined. The percentage of the leaching form in the total element content, i.e. the level of mercury release from the material (leaching level), was also calculated. The amount of mercury leaching was determined by a static method using a batch test 1:10. The highest possibility of leaching mercury is characterized by weathered waste from the Siersza dump and slightly lower analyzed hard coal from the U pper Silesian Coal Basin (USCB). For hard coal samples, the total mercury content is between 0.0275–0.1236 mg/kg. However, the amount of mercury leaching from coal samples is 0.0008–0.0077 mg/kg. The aggregate is characterized by a higher total mercury content in the finest fraction 0–6 mm, within 0.1377–0.6107 mg/kg and much lower in the 80-120 mm fraction, within 0.0508– –0.1274 mg/kg. The amount of elution is comparable in both fractions and amounts to 0.0008–0.0057 mg/kg. Coal sludge has a total mercury content of 0.0937–0.2047 mg/kg. L ow leaching values of 0.0014–0.0074 mg/ kg are also observed. Weathered mining waste has a total mercury content of 0.0622–0.2987 mg/kg. However, leaching values from weathered waste are much higher than from fresh mining waste. This value is 0.0058– –0.0165 mg/kg. In the hard coal extracted from U SCB, the leaching level is 4.7% on average. Mining waste is characterized by a large variation in the proportion of mercury leaching form and the differences result from the seasoning time of the samples. Waste or by-products of hard coal production, such as aggregates and coal sludge, show a mercury washout form at an average level of 1.7%. The proportion of leachable form in weathered waste increased strongly to 7.3%. Elution characteristics vary for different groups of materials tested. Factors such as the type and origin of samples, their granulometric composition and the seasoning time of the material are of fundamental importance and demonstrated in the work.
EN
The rapid physical and chemical degradation of the soil affected the physiological condition of the plants, resulting in a decrease in yields and their quality. Soil additives, consisting of specific mixtures of mineral compounds, should affect the activation of cellular metabolism processes, soil microflora, best adapted to the environment. An important element in the application of fertilizers is their dose, which is closely related to the previously determined soil parameters. This work focuses on the analysis of the impact of struvite soil fertilization on the quality of seepage water, the experiment was carried out in lysimeter columns. Different doses (0.1; 0.5; 1.0 g) of struvite obtained under laboratory conditions by chemical synthesis were used in the study. Three levels of soil wash (10, 20, 30 cm) were analyzed for each dose. For washing, distilled water was used in the amount corresponding to the average annual rainfall for the areas from which the soil was taken for testing. The experiment simulated the monthly precipitation each day, and the resulting effluents analyzed: phosphorus content, pH, conductivity, resistance and sum of dissolved substances Total Dissolved Solids (TDS). Based on the obtained results, it was found that the amount of phosphorus leached is directly related to the dose of struvite in the mixture. The dependence between the amount of phosphorus in the leachate and the pH value was confirmed. Analyzing the effect of struvite fertilization on the soil, an increase in the content of biogenic elements with increasing doses, especially of available forms of phosphorus, has been noted. Despite the soil flushing, the phosphorus content in the soil was still high at the end of the experiment, confirming the low solubility of struvite and the slow release of the constituents.
PL
Postępująca szybko degradacja fizyczna i chemiczna gleby, wpłynęła na stan fizjologiczny roślin skutkując spadkiem plonów i ich jakości. Dodatki doglebowe, składające się z specyficznych mieszanin związków mineralnych powinny wpływać na aktywację procesów metabolizmu komórkowego, mikroflory gleby, najlepiej przystosowanej do środowiska. Istotnym elementem przy stosowaniu nawozów jest ich dawka, która ściśle powiązana jest z określonymi wcześniej parametrami gleby. Niniejsza praca skupiała się na analizie wpływu nawożenia gleby struwitem na jakość wód odciekowych, doświadczenie przeprowadzono w kolumnach lizymetrycznych. W badaniach zastosowano różne dawki (0.1; 0.5; 1.0 g) struwitu uzyskanego w warunkach laboratoryjnych na drodze syntezy chemicznej. Dla każdej dawki analizowano trzy poziomy przemywania gleby (10, 20, 30 cm). Do przemywania zastosowano wodę destylowaną w ilości odpowiadającej średnim rocznym opadom dla terenów z których pobrano glebę do badań. W eksperymencie symulowano miesięczny opad każdego dnia, a w powstających odciekach analizowano: zawartości fosforu, pH, przewodnictwo, oporność i suma substancji rozpuszczonych Total Dissolved Solids (TDS). Na podstawie uzyskanych wyników stwierdzono, że ilość wyługowanego fosforu jest bezpośrednio związana z dawką struwitu w mieszaninie. Potwierdzono również zależność między ilością otrzymanego fosforu w odcieku a wartością pH. Analizując wpływ nawożenia struwitem na glebę, odnotowano wzrost zawartości pierwiastków biogennych wraz ze wzrostem dawki, zwłaszcza dostępnych form fosforu. Mimo przepłukiwania gleby, po zakończeniu doświadczenia zawartość fosforu w glebie była wciąż na wysokim poziomie, potwierdzając niską rozpuszczalność struwitu i powolne uwalnianie składników.
10
Content available remote Physicochemical Properties of Copper Modified Zeolite
EN
Zeolites have been used in environmental engineering mainly in catalytic processes and as ion exchangers in water and wastewater treatment. Selective modified zeolites allow significant improvement in the effectiveness of impurities’ removal without introducing additional reagents to the environment. The final effect of treatment of water solutions is determined by the catalyst used, its physicochemical properties and the process parameters. In this work effectiveness of zeolite modification methods as well as their physical and chemical stability, taking into account the changes that take place during the process of calcination within the temperature range of 250°C to 650°C is presented. A natural clinoptilolite used in the experiment was transformed into the hydrogenous form and subsequently modified with copper (II) ions by coprecipitation with NaOH and Na2CO3. The effect of the method of the zeolite modification on Cu content, the zeolite Leaching capacity and surface charge was evaluated. An analysis of experimental results has shown that calcination temperature does not significantly change the surface charge, but does affect copper speciation. Analysis of EDS spectra by a scanning microscope, which showed that new and regular forms of copper compounds had been formed along the zeolite lattice structure is also presented. The experimental results show that retention of Cu in zeolites was caused by electrostatic interactions between Cu(II) cations and the electronegative surface of the zeolite and coprecipitation of Cu(II) complexes. Physicochemical properties of examined zeolites were affected by processes of hydration, hydrolysis and complexing of Cu with the zeolite matrix as a function of the solution’s pH. Results show that the process of impurities’ removal from water and wastewater depends on the method of zeolite modification and on the solution’s pH.
PL
W inżynierii środowiska zeolity stosowane są przede wszystkim jako wymieniacze jonowe w oczyszczaniu wody i ścieków oraz w procesach katalitycznych. Selektywne modyfikowane zeolity pozwalają na znaczące zwiększenie skuteczności usuwania zanieczyszczeń, jednocześnie nie wprowadzając dodatkowych reagentów do środowiska. O końcowym efekcie decyduje rodzaj zastosowanego katalizatora, jego właściwości fizykochemiczne oraz parametry prowadzenia procesu. W pracy przedstawiono efektywność metod modyfikacji zeolitów oraz ich stabilność fizyczną i chemiczną, z uwzględnieniem zmian zachodzących podczas procesu kalcynacji w zakresie temperatur od 250°C do 650°C. W badaniach zastosowano zeolit naturalny klinoptylolit, który przeprowadzono w formę wodorową roztworem HCl, a następnie poddawano modyfikacji jonami miedzi (II) metodą współstrącania z użyciem NaOH i Na2CO3. Oceniono wpływ sposobu prowadzenia modyfikacji zeolitu na zawartość Cu, jego rozmywalność oraz ładunek powierzchniowy. Analiza wyników badań wykazała, że temperatura kalcynacji nie wpływa istotnie na zmianę ładunku powierzchniowego, ale na formę występowania związków miedzi. W pracy przedstawiono również analizę widm EDS wykonanych mikroskopem skaningowym, która pokazała, że wzdłuż struktury krystalicznej zeolitu zostały utworzone nowe i regularne formy związków miedzi. Wyniki badań wykazały, że zatrzymywanie Cu w zeolitach zachodziło na skutek oddziaływań elektrostatycznych między kationami Cu(II) i elektroujemną powierzchnią zeolitu oraz w wyniku strącania i współstrącania kompleksów Cu(II). Czynnikami wpływającymi na właściwości fizykochemiczne badanych zeolitów są procesy hydratacji, hydrolizy i kompleksowania Cu z matrycą zeolitu w funkcji pH roztworu. Przedstawiona w pracy analiza wyników badań wykazała, że proces usuwania zanieczyszczeń z wód i ścieków uzależniony jest od sposobu modyfikacji zeolitu oraz od pH roztworu.
PL
Przedstawiono analizę możliwości zastosowania metod odzysku fosforu ze ścieków miejskich. Najnowsze tendencje do odzyskiwania tego pierwiastka oparte na krystalizacji związków fosforu dają wprawdzie produkt o dobrej charakterystyce jakościowej, ale nie stanowią technologii ekonomicznie konkurencyjnych wobec obecnych cen surowców do produkcji nawozów mineralnych zawierających fosfor. Najlepsze wyniki z punktu widzenia ekonomiki wdrożenia uzyskano, wykorzystując procesy termicznej utylizacji osadów ściekowych, po których odzyskuje się związki fosforu metodą kwaśnego ługowania.
EN
Ashes from processing of digested sludge from a municipal wastewater treatment plants contained orthophosphates (20–30% in dry mass). Annual tests on potential recovery of P compounds showed that the variability of P recovery potential depended both on a wastewater load and on wastewater flow. Even 54–68% of P contained in the ashes from incinerated sludge was recovered during lab. tests. The overall P recovery from incinerated sludge may replace approx. 20–40% of P needs for contemporary food prodn. The P recovery from ashes was found a very efficient method.
EN
Anatase, as an important titanium resource, is attracting more and more attention in research and application. In this study, an efficient process of comprehensively extracting the titanium and other valuable elements from the anatase mineral was proposed. The effect of particle size, stirring speed, initial sulphuric acid concentration, solid-to-liquid ratio, and reaction temperature on the leaching rate of titanium from anatase was investigated. Under appropriate two-stage countercurrent leaching conditions, with the first stage of the liquid-to-solid ratio of 1/3 g/cm3, reaction temperature of 120 °C, initial acid concentration of 11 mol/dm3, residence time of 30 min, stirring speed of 200 rpm, and the second stage of the liquid-to-solid ratio of 1/3 g/cm3, reaction temperature of 200 °C, initial acid concentration of 13 mol/dm3, residence time of 30 min, and stirring speed of 200 rpm, over 99% TiO2, 99% Al2O3, and 97% Sc2O3 were extracted respectively with quartz still remained in the residue. X-ray diffraction, X-ray fluorescence spectrometer, and scanning electron microscopy/energy-dispersive spectroscopy were used to characterize the anatase samples before and after the leaching. Additionally, the leaching kinetics analysis indicated that both acid concentration and temperature were the most significant parameters for the leaching process. And, the titanium leaching reaction rate was controlled by the diffusion of reactants through the residual layer.
EN
This study focused on the leaching of uranium and thorium from a high grade Ethiopian tantalite ore using sulfuric acid. The effects of variables such as acid concentration, temperature and leaching time were studied. In general, the leaching efficiency of uranium increases with increasing temperature from 100 to 300°C whereas the opposite trend was observed for thorium. The amount of uranium leached increased from 69.1% at contact time of 1 hr to 88.6% when the tantalite ore was leached for 3 hrs. On the other hand, for the experiments conditions considered in this study, the leaching behavior of uranium and thorium did not change significantly with varying sulphuric acid concentration from 70 to 90 wt%. Overall, the highest dissolution of uranium and thorium were achieved at 100°C, 70 wt% H2SO4 concentration and 1 hr contact time.
EN
Naturally, refractory gold is enclosed by sulfide minerals such as pyrite and arsenopyrite and a higher content of organic carbon, which results in difficulty in the recovery of gold. In this study, the flotation gold concentrate before and after pressure oxidation (POX) was analyzed. The analysis of the Eh-pH diagram revealed that pyrite/arsenopyrite would be dissolved in higher oxidation potential. Results of SEM-EDS showed that the surface of minerals became very rough and structure of some particles was destroyed after POX. The XRD measurement showed that pyrite was oxidized to jarosite, and gangue minerals such as quartz and organic carbon were hardly changed. The process of thiosulfate leaching of gold was designed and optimized according to Miscellaneous implemented by Response Surface Methodology (RSM). Based on the results of ANOVA, leaching model was significant. In leaching, [S2O32-] played an important role and the interactions between [S2O32-] and [Cu2+] were significant. The effect of [HA] was relatively weak. Optimum process parameters of the initial reagent concentration were 505.00 mM for [S2O32-], 34.77 mM for [Cu2+], and 0.50 mM for [HA]. Under these conditions, the Au extraction value was about 86.21%, which was significantly higher than that obtained with leaching directly.
EN
In this study, the leaching process of a lead-bearing ore, consisting mainly of cerussite, in an ammonium citrate tribasic medium was investigated. The parameters including temperature, reagent concentration, particle size, and stirring speed were examined. During leaching process, the lead conversion rate increased with an increase in reagent concentration, reaction temperature, and stirring speed, and a decrease in particle size. The results show that about 95% of lead content was extracted from the samples with particle size range of +75-96 μm after 21 min leaching in 1.25 mol/L ammonium citrate tribasic solution at 800 r/min and 40°C. It was found that the leaching reaction followed the shrinking core model. The results indicated that ammonium citrate tribasic could be used as an effective leaching reagent for extracting lead from lead oxide ore.
EN
This work focuses on the hydrometallurgical processing of EAF steelmaking dust in laboratory conditions. The behavior of calcium under the influence of sulphuric acid as the leaching agent is discussed. Due to calcium presence the acid is continuously consumed, gradually leaching the calcium phase from EAF dust as well as other zinc- and iron-containing phases. A thorough composition analysis of the input sample of EAF dust was performed. A kinetic study of calcium showed that its leaching is a very fast process, but most of the calcium reacting with sulphuric acid is precipitated from the solution in the form of CaSO4∙2H2O. This causes greater sulphuric acid consumption, and therefore it is necessary to study the calcium behavior during processing of EAF dust. This work is narrowed with calcium behavior during leaching of EAF dust in sulphuric acid and effect of calcium to extraction other metals into solution.
EN
Nepheline syenite, which is a silica-poor crystalline rock, competes with feldspar in applications such as glass, ceramic filler, and pigment industries. While its appearance is medium coarse granular like granite, main differences between them are nepheline syenite is silica poor, and contains high alumina and alkali content. Turkey has considerable nepheline syenite deposits in Kırşehir Region, and they contain 1.3% Fe2O3 on average, thus cannot be used unless beneficiated by flotation or/and magnetic separation. In this paper, physical and physicochemical experiments were carried out to improve the quality of nepheline syenite ore. After determinations of chemical, mineralogical, and properties of the sample, three different technologies such as flotation, magnetic separation, and leaching were applied on the ore sample, separately and combined. The obtained results showed that the magnetic separation alone could not produce a nepheline syenite concentrate assaying 0.45% Fe2O3. It was not also possible to obtain a nepheline concentrate less than 0.25% Fe2O3 adapting optimum flotation conditions. The best results were found in combination of the high intensity wet magnetic separation and flotation between -212+63 μm particle size, and a final concentrate with 0.20% Fe2O3 and 0.01% TiO2 was obtained. The leaching experiments were conducted to further decrease Fe2O3 content. Finally, a saleable nepheline syenite concentrate for tile, sanitary ware, electrode, glass, and fiberglass industries was obtained with 6.63% K2O, 9.02% Na2O, 0.15% Fe2O3, and 0.01% TiO2 by the weight of 63.9% at the end of the experiments.
EN
Understanding of atomic scale interactions of molecular species with mineral surfaces is needed to bring about mineral processing innovation. In this regard, Density Functional Theory (DFT) methods are well suited. In this work, the outcome of leaching synthetic acanthite –a surrogate for a silver-containing sulfide ore- with both cyanide ion and thiourea are studied with DFT considering solvent effects. The results are correlated to the experimental percentage of silver extracted with each of the leaching agents under similar conditions of molar concentration, temperature and percentage of solids. Our calculations show both leaching reactions to be exergonic and of the same order of magnitude in Gibbs energy of reaction than values determined from thermodynamic tables. Also, less favorable Gibbs reaction energies are obtained for cyanidation in absence of oxygen and thioureation in absence of Fe(II) highlighting the impact of oxidants on the exergonicity of the respective global leaching reactions. Finally, analyzing the percentage of silver extracted from acanthite and the absolute value of Gibbs energies of the respective reaction, we conclude that the more exergonic a leaching reaction, the higher percentage of silver is extracted from acanthite, provided that there is no kinetic control of each of the leaching reactions.
EN
Glasses in the Na2O–B2O3–SiO2–Fe2O3 system with a constant SiO2 content 70 mol% were synthesized using conventional melting in platinum crucibles in SiC-furnace in air. After synthesis and annealing, glasses were heat treated at 550°C for 96–144 hrs to promote phase separation. A tentative region of phase separation for this temperature was outlined. X-ray powder diffractometry results showed three iron-containing phases (Fe3O4, FeSiO3 and β-Fe2O3) forming in the investigated glasses with magnetite being the main phase as it is observed in most of the glasses. Chemical durability studies showed that compositions of phase-separated glasses suitable for synthesis of porous glasses, both iron-free and iron-containing lie in between 4 and 8 mol% of Na2O. Bulk samples of porous glasses were obtained within the chosen region having the following parameters: specific surface area 40–185 m2/g, porosity 30%–45%, pore diameter 3–14 nm. The parameters of porous structure of iron-containing porous glasses are of the same order of magnitude as the porous glass used for the multiferroic nanocomposite synthesis.
EN
The novel technique that will be introduced for modifying surfaces is plasma treatment, which creates a great potential in the development of a variety of functional properties of polymeric membranes. Application of this technique in the processes of membrane modification allows functionalization by the manufacturing metal oxides such as copper oxide, silver oxide, or titanium dioxide on the surface. In this work, the polymeric membranes were activated with low-temperature plasma of different gases (Ar and Ar-O2 ) and subjected to copper oxide deposition. The leaching of copper from the surface of plasmamodified membranes and its permeability and antimicrobial activity were examined. It was found that CuO-modified membranes pre-activated in an Ar or Ar-O2 mixture are characterized by much lower stability than ones without pre-activation. Moreover, the filtration properties of CuO-modified membranes were unchanged compared to native ones, and these filtration materials are characterized by antibacterial properties.
PL
Techniki plazmowe to nowatorskie metody modyfikacji powierzchni, które umożliwiają nadanie różnorodnych właściwości funkcjonalnych membranom polimerowych. Zastosowanie technik plazmowych podczas modyfikacji membran polimerowych umożliwia ich funkcjonalizację poprzez wytwarzanie tlenków metali, takich jak tlenek miedzi, tlenek srebra lub dwutlenek tytanu na ich powierzchniach. W ramach przeprowadzonych prac membrany polimerowe aktywowano niskotemperaturową plazmą w mieszaninie w różnych gazów (Ar i Ar-O2 ), które następnie poddawano modyfikacji przy użyciu tlenku miedzi. Zbadano stabilność związania tlenku miedzi z powierzchnią membran modyfikowanych plazmą i jej przepuszczalność oraz aktywność przeciwdrobnoustrojową. Stwierdzono, że membrany modyfikowane CuO wstępnie aktywowane w Ar lub mieszaninie Ar-O2 charakteryzują się znacznie mniejszą stabilnością niż te bez wstępnej aktywacji. Ponadto właściwości filtracyjne membran modyfikowanych CuO były niezmienione w porównaniu z materiałami natywnymi, a wytworzone materiały filtracyjne charakteryzowały się właściwościami antybakteryjnymi.
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