Ograniczanie wyników
Czasopisma help
Autorzy help
Lata help
Preferencje help
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 159

Liczba wyników na stronie
first rewind previous Strona / 8 next fast forward last
Wyniki wyszukiwania
Wyszukiwano:
w słowach kluczowych:  manganese
help Sortuj według:

help Ogranicz wyniki do:
first rewind previous Strona / 8 next fast forward last
EN
Present in soils, ground and surface waters, manganese is among the most common metals in Earth crust. It is also an essential trace element to the functioning of several enzymes in the human body. However, exposure to high manganese concentrations can also be harmful to humans with psychiatric and motor effects and therefore, manganese concentrations in drinking water and also industrial effluents are regulated. In the current work, the adsorption of Ca2+, Mg2+ and Mn2+ on three different ion-exchange resins: (i) aminophosphonic acid - chelating (Purolite S950), (ii) polyacrylic weak acid cation (Purolite C104E) and (iii) polystyrene strong acid cation (Purolite C100) was investigated. The results revealed that Purolite S950 had the highest Mn2+ uptake (37.9 mg/mL-resin or 0.69 mmol/mLresin) as compared to Ca2+ (3.2 mg/mL-resin or 0.08 mmol/mL-resin) and Mg2+ (~0 mg/mL-resin) and was selected for further kinetics and equilibrium studies. The results indicated Purolite S950 as particularly suited to be applied in the treatment of neutral mine waters with high Mg/Mn ratios. Additionally, Purolite S950 showed a small affinity for Ca2+ and therefore an efficient Mn2+ removal will depend on the Ca/Mn ratio of the mine water under treatment. According to the kinetic analysis, manganese sorption on Purolite S950 was described by the pseudo-second order model (r2 > 0.98) with an activation energy of 6.34 kJ/mol and thus pore-difussion was the rate controlling step of the process. In terms of equilibrium studies, manganese sorption on Purolite S950 followed the Langmuir model with maximum loadings of up to 41.5 mg/mL-resin. The thermodynamic modelling indicated an exothermic process (-85.0 kJ/mol, as standard enthalpy) with a standard entropy of -274 J/mol×K, which was ascribed to the release of two adsorbed H+ ions for each Mn2+ ion taken up from solution.
EN
Because of their excellent formability and sufficient mechanical properties, aluminium alloys based on an aluminium–iron–silicon system are very popular materials, commonly used in the production of thin foils. Alloy EN AW-8011 contains approximately 0.50–1.00 wt. % of iron and 0.40–0.80 wt. % of silicon. The other elements, including manganese and magnesium, are present only as impurities. However, these two elements are generally very effective enhancers of mechanical properties. Due to their very low concentrations in alloy EN AW-8011, the influence of manganese and magnesium on mechanical properties is often overlooked. In the research work discussed in the article, the properties of two Twin-Roll cast aluminium alloy EN AW-8011 containing various amounts of manganese and magnesium were investigated using optical microscopy, scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX) and tensile tests. The test results revealed that higher contents of magnesium and manganese significantly changed the mechanical properties of the alloy.
PL
Ze względu na swoją doskonałą odkształcalność i odpowiednie właściwości mechaniczne, stopy aluminium na bazie układu aluminium – żelazo – krzem są bardzo popularnymi materiałami stosowanymi w produkcji cienkich folii. Stop EN AW-8011 zawiera około 0,50–1,00% żelaza oraz 0,40–0,80% krzemu. Pozostałe pierwiastki, w tym, m.in. mangan oraz magnez, występują jedynie w postaci zanieczyszczeń, chociaż na ogół bardzo skutecznie poprawiają właściwości mechaniczne stopów. Ze względu na bardzo niskie stężenia manganu i magnezu w stopie EN AW-8011, ich wpływ na właściwości mechaniczne stopu jest często pomijany. Artykuł przedstawia badania właściwości dwóch, uzyskanych metodą Twin-Roll, odlewanych stopów aluminium EN AW-8011 o różnej zawartości manganu i magnezu. Badania obejmowały obserwacje z użyciem mikroskopu optycznego oraz skaningowego mikroskopu elektronowego, analizy z zastosowaniem spektroskopii rentgenowskiej z dyspersją energii oraz próby rozciągania. Badania wykazały, iż większa zawartość magnezu oraz manganu prowadzi do istotnych zmiany właściwości mechanicznych ww. stopu.
PL
W niniejszym artykule zajęto się sprawdzeniem intensywności wymywania poszczególnych jonów metali z różnych warstw hałdy żużlu stalowniczego pochodzącej z huty stali w Ostrowcu Świętokrzyskim. Wymywania dokonano symulując opady atmosferyczne - wykorzystując wodę destylowaną, jak i sztuczne kwaśne deszcze (roztwór kwasu azotowego (V) o pH ≈ 2). Próbki pobrano z terenu składowiska odpadów poprzemysłowych, należących do firmy Madrohut w Krakowie, zarówno z wierzchniej warstwy hałdy jak i z głębokości 0.5 m w głąb hałdy, które zostały następnie poddane suszeniu na powietrzu. Do oznaczeń wykorzystano metodę Atomowej Spektrometrii Absorpcyjnej (ASA), a przedmiotem oznaczeń były cztery pierwiastki: Mg, Mn, Cr i Zn. Celem było sprawdzenie przenikania jonów metali z hałd żużlu stalowniczego do potencjalnych wód gruntowych i możliwego przez to zanieczyszczenia środowiska naturalnego.
EN
The presented article concerns an examination of the intensity of metal ion leaching in different layers of a steel slag heap originating from a steel mill located in Ostrowiec Świętokrzyski. Leaching was induced by simulating precipitation, using destilled water, and acidic rainwater (nitric acid solution of pH ≈ 2). The samples were collected, on site of factory landfill area of Madrohut company located in Cracow, from both surface layer the heap as well as from the layer around 0.5 m within the heap itself which were all subsequently air-dried for the period of two weeks. Quantification was conducted using the Atomic Absorption Spectrometry method (AAS) within a scope of four metal elements: Mg, Mn, Cr and Zn. The goal was to examine the metal ion leaching from steel slag heap into potential groundwater supply and the possibility of polluting the environment as the result.
PL
W niniejszej pracy dokonano analizy ilości wymywanych pierwiastków (cynku, magnezu i manganu) jakie mogłyby wydostać się do środowiska z odpadów hutniczych wraz z zastosowaniem ich w budownictwie dróg i nawierzchni asfaltowych. Badanym materiałem były hałdy zawierające żużel stalowniczy, muł z oczyszczania spalin metodą mokrą z oczyszczalni z Dąbrowy Górniczej, świeży żużel oraz żużel po leżakowaniu zlokalizowane na terenie Zakładu Odzysku Surowców Madrohut Sp. Z o.o. w Krakowie. Analizy wymywanych pierwiastków dokonano metodą atomowej spektroskopii absorpcyjnej. Otrzymane wyniki porównano z zawartościami pierwiastków w różnych typach gleb celem określenia czy mogłyby okazać się toksyczne dla ekosystemu w pobliżu dróg. Badania wykazały, że największą zawartością oznaczanych pierwiastków cechują się hałdy z mułu po oczyszczaniu spalin metodą mokrą, natomiast w wielu przypadkach zawartość wybranych pierwiastków była poniżej granicy oznaczalności metodą ASA. Wykazano, że otrzymane wartości zawartości pierwiastków nie powinny stanowić zagrożenia dla środowiska w przypadku zastosowania odpadów jako surowca w budownictwie drogowym.
EN
In the presented paper, the amount of washed out elements (zinc, magnesium and manganese) from metallurgical wastes used for road construction might be released to the environment. The analysed samples were obtained from the wastes heaps containing slug and loam from the exhaust gases purification system in Dąbrowa Górnicza. The waste heaps were localized at site belonging to the Raw Materials Retrieval Company “Madrohut” Sp.Z o.o. in Kraków. The washed out elements’ concentrations were determined by means of Atomic Absorption Spectrometry. The obtained results were compared with the elements’ concentrations in various soils, to determine whether such materials could be toxic for the environment. It can be concluded that the highest concentrations of the elements was found in the loam samples, but in many instances, the elements’ concentrations were below the detection limits. It was shown, that the determined content of the examined elements should not be dangerous for the environment if used in road construction.
PL
Mangan jest jednym z wielu pierwiastków naturalnie występujących w przyrodzie. Jest on niezbędny do prawidłowego działania organizmów ludzi, roślin oraz zwierząt lądowych i wodnych. Jego największe złoża znajdują się w Republice Południowej Afryki, jednakże wiele krajów, takich jak: Australia, Brazylia, Chiny, Gabon, Ghana, Wybrzeże Kości Słoniowej, Indie czy Malezja, posiadają całkiem spore zasoby tego pierwiastka. Mangan w procesach fizjologicznych, zachodzących w organizmach wielokomórkowych, odgrywa bardzo ważną rolę jako element strukturalny metaloenzymów, odpowiedzialnych za wiele kluczowych funkcji, takich jak: redukcja stresu oksydacyjnego, neutralizacja zbędnego materiału genetycznego, detoksykacja organizmu czy prawidłowe działanie układu nerwowego. Na całym świecie prowadzone są badania, których celem jest empiryczne potwierdzenie odpowiednich stężeń manganu dla rozlicznych zwierząt zamieszkujących różne środowiska na naszej planecie. Prowadzi się również badania dotyczące stężeń manganu w różnorodnych środowiskach, w których żyją różne gatunki zwierząt, roślin oraz ludzie. Mangan, podobnie jak wiele pierwiastków i związków chemicznych w nadmiarze, może powodować efekty uboczne, które w przypadku ludzi obejmują szereg zaburzeń neurologicznych, niekiedy podobnych do objawów choroby Parkinsona.
EN
Manganese is one of many elements naturally occurring in nature. It is necessary for the proper functioning of human bodies, plants and land and aquatic animals. Its largest deposits are located in South Africa, however, many countries such as Australia, Brazil, China, Gabon, Ghana, Cóte d'lvoire, India and Malaysia have quite large resources of this chemical element. Manganese plays a very important role in the physiological processes occurring in multi cellular organisms, as a structural element of metalloenzymes, responsible for many key functions, such as: reduction of oxidative stress, neutralization of unnecessary genetic material, detoxification of the body and proper functioning of the nervous system. Research is being conducted around the world to empirically confirm the appropriate concentrations of manganese for various animals living in different environments on our planet. Research is also carried out on manganese concentrations in various environments where various types of animals, plants or people live. Manganese, like many elements and chemical compounds in excess, can cause side effects, which in humans include a number of neurological disorders, sometimes similar to the symptoms of Parkinson's disease
EN
Manganese concentration in green and black tea (10 samples of each type) was determined by means of graphite-furnace atomic absorption spectrometry. Both the dry leaves and the infusions were analysed. The concentration of manganese in dry leaves was in the range of 502–1277 mg · kg−1 for black tea and 798–1906 mg · kg−1 for green one. Since lemon juice is commonly added for tea to enrich its taste, citric acid was used to simulate lemon juice influence on manganese concentration in the infusions. The infusions prepared with and without citric acid addition were analysed and the results showed significant influence of citric acid on manganese leaching. The average extraction levels of manganese from black tea equal 16% (for non-acidified infusions) and 34% (for acidified ones) while these values for green tea equal 13% and 38%, respectively. Statistical evaluation of the results showed that the differences between acidified and non-acidified infusions were statistically significant. High manganese content makes the tea an important source of manganese in human diet.
PL
Stwierdzono ilościowe wytrącanie szczawianów kobaltu(II) i manganu(II) (stężenia metali poniżej LOD: Co < 0,35 ppm, Mn < 0,27 ppm) w stężonym roztworze kwasu octowego (90% mas.), powszechnie stosowanym jako rozpuszczalnik w przemysłowych procesach utleniania p-ksylenu do kwasu tereftalowego. Obecność zanieczyszczeń typowych dla procesu utleniania p-ksylenu, czyli kwasu benzoesowego, kwasu bromowodorowego oraz jonów sodu nie miała negatywnego wpływu na powstawanie osadów. Obecność stałego kwasu tereftalowego w mieszaninie reakcyjnej miała pozytywny wpływ na proces odzyskiwania katalizatora. Zaobserwowano, że szczawiany tworzą aglomeraty na powierzchni stałego kwasu tereftalowego, co ułatwia oddzielenie osadu od cieczy macierzystej. Ponadto potwierdzono wysoką efektywność wytrącania w szerokim zakresie stężeń metali (50-1600 ppm). Wyniki pokazują, że strącanie kwasem szczawiowym jest skuteczną metodą odzyskiwania katalizatorów homogenicznych zawierających związki kobaltu(II) i manganu(II).
EN
A 1% soln. of (COOH)₂ in 90% MeCOOH was added to a 90% MeCOOH soln. contg. Co and Mn ions at concns. of 500 and 300 ppm, resp., and impurities typical of the oxidn. of p-xylene to C₆H₄(COOH)₂ (BzOH, HBr and Na ions) in amts. simulating the mother liquor compn. of a real industrial process. After mixing, the Co and Mn contents of the decanted liq. were detd. by AAS. Presence of impurities had no neg. impact on the ppt. formation. The presence of solid C₆H₄(COOH)₂ in the reaction mixt. had a pos. impact on the catalyst recovery process. Oxalates formed agglomerates on the surface of the solid C₆H₄(COOH)₂ which facilitated the sepn. of the ppt. from the mother liquor. The pptn. with (COOH)₂ is an efficient recovery method of spend Co(II) and Mn(II) homogeneous catalysts.
EN
According to Council Directive 98/83/EC on the quality of water intended for human consumption, concentration of the manganese in the drinking water should not exceed 0.05 mg/l. However, this level of manganese concentration is higher ingroundwaterof a community (Vitia town) in Kosovo. Groundwater is used for drinking supply of some villages and is only chlorified continuing to the reservoir from where is gravitationallydisseminated to the villages. The manganese level of the water is at the range 0.3 to 0.6 mg/l. Limestone has been provenby many researchers to be a very effective filter material in manganese removal for groundwater.A miniature filtration unit was modeled to investigate the removal efficiency of manganese.The unit consists of local limestone, where a single materialis folded in three layers of different grainsizes. In fact, the aim of this paper was to assess whether limestone as a single material acting as a "multi-media filter" can reduce the manganese concentration in groundwater. On the basis of the analysis of the single snapshot sample,the removal of manganese achieved more than 95% in filtered water. Particularly, this study demonstrates that filtering the water through three layers of different grain sizes of limestone ("multi-media limestone filter") can be a good alternative for manganese removal in groundwater.
EN
Calcium carbide waste (CCW), the rest of the carbide welding workshop industry, is available in quite a lot and is immediately disposed of into the environment. Because CWW has a high pH value and a large specific surface area, it can act as an adsorbent in removing metals from groundwater. The content of metals in groundwater is indicated by a reddish color; however, upon contact with air, groundwater oxidation causes iron ions and manganese ions to precipitate. Synthetic groundwater was prepared in this experiment using reagents containing and . Observations were made in a batch process to assess the potential and ability of CCW to reduce iron and manganese levels in groundwater. In this study, to achieve equilibrium, CCW was mixed with 100 mL of synthetic solution and shaken at 25°C with a shaker. Operating time, levels of Fe(II) and (Mn(II) metals, and the mass of CCW were some of the parameters studied in this study. CCW was very good at reducing levels of iron ions and manganese ions after 60 minutes of operation. The percentage of removal of iron and manganese ions respectively – successively increased from 93.765 to 97.99% for iron ions and manganese ions from 91.83 to 95.14% for the initial concentration range of 40 mg/L, 60 mg/L, 80 mg/L, and 100 mg/L. Furthermore, the adsorption kinetics of CCW adsorbent in a mixture of iron ion and manganese ion solutions is a second-order kinetic equation. This confirms that the adsorption of CCW on iron ions and manganese ions is a chemisorption process. Calcium carbide waste has the potential to act as an absorbent of heavy metals in groundwater, especially iron and manganese ions.
EN
The work concerns the effects of the treatment of groundwater contaminated with iron and manganese compounds taken from quaternary deposits. In the treatment process, a simple reagent-free technology based on aeration and rapid filtration processes was used. The article presents an analysis of the results of the quality of treated and abstracted water in the years 2008–2020. The period analyzed covers the modernization of the WTP, which was carried out in 2012. The purpose of modernization was to increase the efficiency of the WTP. After the modernization of the station, the efficiency of iron and manganese removal was found to be very high (99%), and the sequence of technological processes used was correct. The devices operated in the WTP work effectively by treating the water directed to the distribution system, which meets the Polish and EU quality requirements for water intended for human consumption.
EN
Acid mine drainage (AMD) has the characteristics of high heavy metal ion content and low pH. This study aimed to synthesize the CaO/Fe3O4 composite for the adsorption of iron and manganese ions from acid mine drainage. CaO was synthesized from the shells of green mussels (Perna viridis). The CaO/ Fe3O4 composites were characterized using XRD, BET surface area, SEM-EDS, and VSM. The functional groups of the composite before and after adsorption were analyzed using FTIR. The adsorption of Fe(II), Fe(III), and Mn(II) ions was carried out with the batch method to determine the effect of pH, contact time, and initial concentration of metal ions. The CaO/ Fe3O4 composite has magnetic properties, as indicated by the saturation magnetization value of 65.49 emu/g. The Langmuir and Freundlich isotherm models were used to describe the adsorption isotherm of the composite for Fe(II), Fe(III), and Mn(II) ions. Investigations were also conducted on adsorption kinetics, including pseudo-first-order and pseudo-second-order, as well as adsorption thermodynamics comprising free energy, enthalpy, and entropy. Pseudo-first-order and Langmuir isotherms are suitable to describe the adsorption of Fe(II), Fe(III), and Mn(II) ions with adsorption capacities of Fe(III) > Fe(II) > Mn(II). Moreover, the adsorption of all ions using the composite occurred spontaneously. The removal effectiveness for Fe and Mn ions from AMD using CaO/ Fe3O4 composite, reached 90.41 and 97.59%, respectively, in volume 100 mL AMD, composite mass 0.4 g, and a contact time of 60 minutes.
EN
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%).
EN
The production wastewater contains phenol from the Non-Destructive Testing (NDT) unit because it uses solvents; meanwhile, the manganese originates from the metal material washing process. On the basis of laboratory test results, the wastewater originating from the NDT unit of Y Industry, resulted in a phenol level of 2.33 mg/L, exceeding the quality standard of 0.5 mg/L and manganese level of 14.13 mg/L that exceeded the quality standard of 2 mg/L, based on the Regulation of the Minister of the Environment Number 5 of 2014 concerning Wastewater Quality Standards. This research used the pretest-posttest experimental research design without control. The sample in this study was wastewater from the NDT unit of the Y Industry. The average phenol level after passing through the adsorbent media at a thickness of 40 cm, 60 cm, and 80 cm resulted in 0.99 mg/L with 63% reduction, 0.60 mg/L with 77% reduction, and 0,28 mg/L with 89% reduction, respectively. The average manganese level after passing through the adsorbent media at a thickness of 40 cm, 60 cm, and 80 cm resulted in 0.10 mg/L with 61% reduction, 0.06 mg/L with 76% reduction, and 0,05 mg/L with 80% reduction, respectively. The most effective thickness variation in reducing the phenol and manganese levels of NDT wastewater is 80 cm thickness.
EN
North of the Central Anatolian Crystalline Complex and bordered by the İzmir-Ankara-Erzincan Suture Zone, mineralization occurs within ophiolites known as Anatolian Ophiolite Complex. The mineralization is present within banded, laminated and lenticular radiolarites which are intensely fractured and folded. It is distributed around Derbent, Baltasarilar, Cihanpasa, Buyukmahal, Eymir and Kadisehri where pyrolusite, psilomelane, manganite and braunite comprise the main paragenesis and jacobsite, magnetite, limonite and goethite are minor phases. The negative Eu anomaly suggests that the hydrothermal source was distant from the mineralization area or was mixed with seawater. All samples from the Cihanpasa and Buyukmahal areas have a negative Ce anomaly and resemble low-temperature hydrothermal mineral deposits. Samples from other locations (Derbent, Baltasarilar, Cihanpasa, Eymir, Buyukmahal, Tarhana) are characterized by both negative and positive Ce anomalies. From this it can be inferred that both hydrothermal and hydrogenetic processes were active in mineralization. High Ba contents and a LREE-enriched pattern together with negative Ce anomalies and trace element distributions indicate that the mineralization in the area was derived from a primary hydrothermal source. In addition, diagenetic and epigenetic processes may also have played an important role in the manganese mineralization.
15
Content available remote Bioremediacja wód gruntowych – usuwanie żelaza i manganu
PL
Bioremediacja to zaawansowane technologie wykorzystujące warunki środowiskowe (fizyczne, chemiczne, biochemiczne lub mikrobiologiczne), w celu stymulacji mikroorganizmów zdolnych do detoksykacji wód z zanieczyszczeń organicznych lub nieorganicznych. Bioremediacja wód stała się jedną z najpopularniejszych, szeroko stosowanych technologii oczyszczania wód gruntowych, ze względu na stosunkowo niski koszt oraz możliwość adaptacji do lokalnych warunków. Artykuł stanowi przegląd najnowszej wiedzy na temat metod biologicznego usuwania żelaza i manganu z wód gruntowych.
EN
Bioremediation uses advanced technologies and environmental conditions (physical, chemical, microbiological or biochemical), to stimulate microorganisms to detoxify water with organic or inorganic contaminants. Water bioremediation has become one of the most common, widely used groundwater treatment technologies due to its relatively low cost and the ability to adapt to local conditions. This article reviews the latest knowledge on biological methods for removing iron and manganese from groundwater.
EN
The article examines the ability of natural clays to extract heavy metal ions from aqueous solutions by ion exchange. The process of extracting metal ions was considered on the example of the absorption of manganese, nickel and cobalt from natural waters. In order to study the chemical and mineralogical composition of natural kaolin, the following were used in the work: X-ray diffraction and X-ray phase methods, as well as IR spectroscopy. The article presents a comparative analysis of the adsorption of manganese, cobalt and nickel ions on natural kaolin under different temperature conditions. The nature of the interaction of the studied metal ions with kaolin was established. The results obtained on the adsorption of the ions under study show the efficiency of using natural kaolin clay for water purification.
17
Content available remote Compost produced with addition of sewage sludge as a source of Fe and Mn for plant
EN
Direct application of sewage sludge to soil is controversial due to, among others, its highly variable composition, odour, and risks for health. The obtained composts with the addition of sewage sludge were tested for the contents and availability of manganese and iron. Once composts were applied to the soil, their effect on the content and availability of Mn and Fe in soil and bioaccumulation in the plant were determined. The addition of sewage sludge enriched composts with manganese and iron, but did not increase the content of water-extracted forms of Mn and Fe. The compost with addition of biochar had more organic matter-bound forms of Mn and Fe. Composts amended with sewage sludge had lower effect on the amount of Poa pratensis L. biomass than maize straw compost. The content of Mn and Fe in Poa pratensis L. was in the range permissible for biomass used as fodder. Smaller addition of all composts to the soil significantly increased the content of mobile manganese forms; however, neither the type nor the dose had effect on the content of iron mobile forms. There was no significant differences in the content of organic matter-bound forms of Mn and Fe in soil after the application of composts.
EN
Chemical time delay detonators are used widely in mine blasting applications. In order to achieve effective blasting, detonations must follow a precisely controlled timing sequence in a specified firing pattern. Silicon fuel-based pyrotechnic compositions are widely used in mining detonators and are well studied. However, some of these formulations are deemed to be problematic, as they contain heavy metals which are bio-accumulative and toxic to the environment. Therefore, there is need to explore alternative formulations which are suitable for these applications. Manganese-fueled systems are attractive due to their metallic properties and several oxidation states of the manganese fuel. This study focused on characterizing the burn properties of Mn/Bi2O3 compositions for slow to intermediate time delay applications. The compositions supported combustion in the 25 to 55 wt.% Mn range in an inert helium atmosphere. Burn rates between 2.5 and 11.2 mm·s–1 were recorded in open burn tests, whilst closed burn tests in glass tubes resulted in burn rates of 6.3 to 11.2 mm·s–1. Both X-ray diffraction analysis of the reaction products and thermodynamic simulations confirmed that MnO and Bi are the main reaction products, with unreacted Mn and Bi2O3 also being detected. This suggests that the dominant reaction for this composition is a simple thermite-type reaction.
PL
W niniejszej pracy dokonano analizy wpływu czasu składowania hałd na zawartość wybranych pierwiastków metali ciężkich. Badanym materiałem były dwie hałdy szlamów i osadów pofiltracyjnych z oczyszczania gazów odlotowych, które różniły się czasem składowania. Analizowano je pod kątem wilgotności oraz zawartości cynku, manganu i chromu wykorzystując metodę absorpcyjnej spektroskopii atomowej. Hałda "Dąbrowa Stara", która pochodzi z przełomu roku 2020/2021 wykazała wilgotność na poziomie 39%. Natomiast hałda "Dąbrowa Nowa" została dostarczona we wrześniu 2021 r. i charakteryzowała się wilgotnością 47%. Otrzymane zawartości wody w próbkach zgadzają się z przedziałem otrzymanym przez firmę dla tego rodzaju surowca (30-50%). Badanie zawartości metali ciężkich wykazało największe stężenie cynku ze wszystkich oznaczanych pierwiastków, wyniosło ono dla próbki „Dąbrowa Stara” 17119 [μg/g], a dla próbki „Dąbrowa Nowa” 20385 [μg/g]. Najmniejszą ilość w badanych materiałach stanowił chrom, którego zawartość była nieznaczna. Dla próbki „Dąbrowa Stara” wartość oznaczonego stężenia wyniosła 127 [μg/g], a dla „Dąbrowa Nowa” 150 [μg/g]. Wykazano, że hałda "Dąbrowa Nowa" jest bardziej bogata w cynk, chrom i mangan niż hałda "Dąbrowa Stara". Różnice w zawartościach wykrywanych składników mogły być efektem wymywania ich np. poprzez opady deszczu co było spowodowane różnym czasem składowania obu hałd.
EN
In this publication, the effect of heap storage time on the content of the selected heavy metals was analysed. Two heaps of sludges and filter sludges from waste gas treatment, which differed in storage time, constituted the studied material. They were analyzed for moisture content and zinc, manganese and chromium concentrations using atomic absorption spectroscopy. „Dąbrowa Stara” heap, which dates back to the turn of 2020/2021, showed moisture content of 39%. The „Dąbrowa Nowa” heap, on the other hand, was delivered in September 2021 and had a moisture content of 47%. The obtained water contents in the samples agreed with the range obtained by the company for this type of raw material (30- 50%). The analysis of heavy metal contents showed the highest concentration of zinc of all determined elements, which was 17119 [μg/g] for the sample "Dąbrowa Stara" and 20385 [μg/g] for the sample "Dąbrowa Nowa". Chromium was the least abundant in the studied materials and its content was insignificant. For the sample "Dąbrowa Stara" the value of determined concentration was 127 [μg/g], and for "Dąbrowa Nowa" 150 [μg/g]. It was shown that the „Dąbrowa Nowa” is richer in zinc, chromium and manganese than the „Dąbrowa Stara”. The differences in the contents of the detected components could be the effect of their leaching e.g. by rainfall, which was caused by the different time of storage of the two heaps.
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.
first rewind previous Strona / 8 next fast forward last
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.