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Ni-pd/al(2)o(3) catalyst supported on reticulated ceramic foam for dry methane reforming
No full textIn the present study, Ni-Pd/Al2O3 catalyst supported on alpha-Al2O3 based foam was prepared and evaluated in the dry methane reforming process. Corresponding metal chlorides were deposited to the foam surface by impregnation of the foam with ultrasonically aerosolized salt solutions at 473 K and drying at that temperature. Calcination step was excluded and the catalyst was reduced at very low temperature 533 K. The reforming experiment lasted for 3 h, with standing time of 1 h at the following temperatures: 873, 973 and 1023 K. Conclusions on selectivity, catalytic activity and stability were reached on the basis of CO and H-2 yields
Exploitation properties of ni-pd/al2o3 catalyst supported on ceramic foam
No full textThe goal of this research was to examine exploitation properties of Ni-Pd/Al2O3 catalyst supported on alpha-Al2O3 based foam in the dry methane reforming. The catalyst was prepared by using aerosol method. Chloride precursors for Ni and Pd were reduced by hydrogen at low temperature of 533 K, without previous calcination. The reforming experiment was performed for 3 h, with standing time of 1 h for each of the following temperatures: 873, 973 and 1023 K. Conclusions on selectivity, catalytic activity and stability were made on the basis of CO and H-2 yields
Acid leaching of oxide-sulfide copper ore prior the flotation: A way for an increased metal recovery
No full textRudnik bakra Bor, lokalitet Cerovo, sadrži više rudnih tela koja sadrže značajnu količinu oksidnih minerala bakra u svojim površinskim slojevima (> 40%). To su najvećim delom karbonatni minerali, uz nešto kuprita i hrizokole, a od minerala gvožđa preovlađuju hematit, limonit i nešto magnetita. Prerada mešanih sulfidno-oksidnih ruda stvara tehnološke probleme pri flotiranju, smanjujući ionako nizak stepen iskorišćenja, pa ukupni gubici na bakru dostižu i do 60%. U cilju povećanja ukupnog stepena iskorišćenja bakra, prilazani su rezultati luženja oksidnog bakra iz oksidno-sulfidne rude i flotacije sulfidnog bakra iz čvrstog ostatka luženja. Maksimalno iskorišćenje oksidnog bakra tokom jednostepenog luženja sa 0,3 M rastvorom H2SO4 i vremenu od 180 min je 73%, a sulfidnog bakra u procesu flotacije je 78%, za 20 min i dodatak PEX kolektora od 30 g/t koncentrata. Ukupno iskorišćenje bakra u procesima luženja i flotacije rude iznosi oko 75%. Koncentracija bakra u lužnom rastvoru iznosi 1,2-1,7 g / dm3, a sadržaj bakra u koncentratu nakon flotacije je oko 5%. Na osnovu izvršenih eksperimentalnih rezultata predložena je tehnološka šema za preradu mešovite oksidno-sulfidne rude bakra.The copper mine Cerovo - East Serbia, as well as the other ore bodies in its vicinity, contains a significant amount of oxide copper minerals in their uper layers (>40%). Processing of such mixed ores by the existing concentration technologies leads to a substantial copper losses ( LT 60%). Reduction of 'oxide copper', by acid leaching prior the flotation concentration, can increase the overall copper efficiency up to more than 70% in the single-stage leaching, achieving an efficiency in the flotation concentration stage higher than 75%. Based on the performed experimental results, the flow sheet for processing of the mixed oxide-sulfide copper ore is proposed
Effect of chemical treatment on adsorption characteristics of apricot stone biosorbent
No full textU radu je ispitan uticaj hemijske modifikacije, primenom NaOH, na strukturne promene lignoceluloznog ostatka koštica kajsije (KK) i na adsorpcioni kapacitet biomaterijala prema jonima bakra. Biomaterijal pre i posle hemijskog tretman ispitan je skenirajućom elektronskom mikroskopijom (SEM) i Furijeovom transformacionom infracrvenom spektroskopijom (FTIR). SEM je pokazao da nakon hemijskog tretmana struktura materijala je rapavija kao posledica uklanjanja voska, masti i ostalih nečistoća i pristupačnija molekulima vode i jonima bakra. FTIR analiza je pokazala da pik koji se kod prirodnog materijala javlja na 1735 cm-1 (ukazuje na valencionu vibraciju -C=O veze, koja potiče od karboksilnih grupa ili estra ili voskova i masti) kod modifikovanog materijala je značajno redukovan. Određivanjem tačke nultog potencijala utvrđeno je da je posle modifikacije došlo do promene naelektrisanja površine materijala (pHpzc kod KK je 4,9 a kod KKM je 6,0). Kao posledica tretmana, promene koje su se dogodile uslovile su pet puta veči adsorpcioni kapacit kod modifikovanog (10,8 mg/g) u odnosu na prirodni biomaterijal (2,5 mg/g).This paper deals with investigation of alkali treatment effect on structural changes of apricot stones lingo-cellulosic residue (KK) and on adsorption capacity based on adsorption of Cu(II) ions from wastewater. Characterization of natural and alkali treated biomaterial were done by FT-IR and SEM. SEM micrographs showed that the removal of the surface impurities after treatment, improves the surface roughness of KK thus opening more hydroxyl groups and other reactive functional groups on the surface. FT-IR spectrum showed that the peak at 1735 cm-1 from of untreated KK, which is assigned to aromatic carbonyl or carboxyl C=O stretching of carboxylic acids or their esters, was reduced after treatment. After treatment change of point of zero charge value of modified biomaterial was evident: from pHPzc=4.9 (KK) to pHPzc=6.0 (KKM). Overall, the changes made by alkali treatment of KK, resulted in five times higher adsorption capacity
Low-temperature Ni-As-Sb-S mineralization of the Pb(Ag)-Zn deposits within the Rogozna ore field, Serbo-Macedonian Metallogenic Province: Ore mineralogy, crystal chemistry and paragenetic relationships
No full textThe Rogozna ore field (ROF) belongs to the Serbo-Macedonian Metallogenic Province (SMMP), and covers a part of the western Dinarides rim and the Vardar ophiolite zone, situated within the Neogene volcanogenic-intrusive complex of calc-alkaline and shoshonitic rocks within the territories of Serbia and Kosovo. It is well-known for its Cu(Au, Pb, Zn) skarn mineralization and Pb(Ag)-Zn hydrothermal deposits and occurences. Mineral associations, deposition order and genesis of the ROF were discussed in detail. Complex ore parageneses were determined in the Crnac, Plakaonica, and Kaludjer Pb(Ag)-Zn deposits and are composed of the following minerals: sulfides (pyrrhotite, chalcopyrrhotite, chalcopyrite, sphalerite, galena, pyrite, marcasite, millerite, bravoite), sulfosalts (arsenopolybasite, tetrahedrite, Ag-bearing tetrahedrite, Zn-bearing tetrahedrite, semseyite, heteromorphite, jamesonite, ferrokesterite), arsenides (nickeline), sulfarsenides and sulfantimonides (gersdorffite, Sb-bearing gersdorffite, Fe-bearing gersdorffite, As-bearing ullmannite, arsenopyrite), native metals (native Au, native Ag), oxides (Cr-spinel, rutile, anatase, leucoxene, magnetite, hematite) and gangue minerals (quartz, silicates, chalcedony, carbonates, monazite(Ce), barite, gypsum, anglesite, cerussite, smithsonite, zaratite, limonite). The high-, medium-, and low-temperature hydrothermal mineral assemblage occur throughout the Pb(Ag)-Zn deposits at Kaludjer-Crnac-Plakaonica ore system, in which the whole ore field as high- to medium-temperature hydrothermal formed at shallow to moderate depth. The following stages of ore mineral formation are recognized in the Pb-Zn mineral assemblage at the ROF: i) pre-ore; ii) high-temperature hydrothermal; iii) hypogene; iv) medium-temperature hydrothermal; v) low-temperature hydrothermal; and vi) supergene. Generally, there are two types of mineralization, brecciated ore veins with ribbon-like textures deposited in amphibolites or in contact with quarz latites, and impregnations within columnar ore bodies hosted in silicified and carbonated serpentinites (listwaenites). Ni-mineralization is represented by significant sulphide, arsenide, sulfarsenide, and sulfantimonide occurrences, but the most significant consists of gersdorffite-ullmannite series (GUS) minerals. It is the most developed in the Kaludjer deposit, much lesser at Plakaonica, whereas in the Crnac deposit it was not noted. The importance of the Ni mineralization is of scientific interest for now, as the attention has been directed only to the exploration of lead and zinc. However, it is believed that plans for the future will be focused on a detailed study of nickel
Definisanje nove proizvodne linije flotacijske koncentracije minerala bakra, olova i cinka iz polimetalične rude ležišta „ Podvirovi i Conjev kamen“ – Bosilmetal primenom savremenijih tehničko-tehnoloških rešenja
No full textU cilju ispitivanja mogućnosti efikasne pripreme i koncentracije minerala bakra, olova i cinka iz rude ležišta „Podvirovi i Conjev kamen“ – BOSILMETAL, u laboratoriji za PMS - ITNMS, u poluindustrijskom postrojenju sprovedena je tehnološka proba na reprezentativnom uzorku ovog ležišta. Kao podlogu za definisanje tehničko-tehnoloških uslova procesa flotacijske koncentracije na poluindustrijskom nivou, u ITNMS je urađen set preliminarnih a kasnije i detaljnih laboratorijskih testova neophodnih za precizno definisanje parametara koncentracije korisnih komponenti i povećanje nivoa simulacije industrijskog procesa flotiranja na poluindustrijskom nivou. Zadatak u ovoj fazi tehnoloških istraživanja bio je da se rezultati ostvareni u laboratoriji potvrde na poluindustrijskom nivou u cilju definisanja tehničko-tehnoloških parametara procesa kao neophodnih podloga za izradu Studije izvodljivosti, Elaborata o rudnim rezervama I projektovanje postrojenja za preradu rude rudnika BOSILMETAL. Krajnji cilj ovih ispitivanja je dobijanje koncentrata bakra, olova i cinka u poluindustrijskom postrojenju u laboratoriji za PMS ITNMS, prema komercijalnim uslovima i zahtevima za dalju pirometaluršku preradu. Prema predlogu tehničko-tehnološkog rešenja koji je proistekao iz sagledavanja Investitora I saradnika ITNMS na realizaciji ovog zadatka, formirana je šema poluindustrijskih ispitivanja po principu dobijanja zasebnih koncentrata bakra, olova i cinka. Rezultati ostvareni tokom tehnoloških ispitivanja na laboratorijskom i poluindustrijskom nivou definisani su kao podloga za projektovanje postrojenja za pripremu i koncentraciju minerala bakra, olova i cinka iz polimetalične rude ležišta „Podvirovi i Conjev kamen“ – BOSILMETAL Kao rezultat kompletnih tehnoloških ispitivanja u vidu obaveze prema Investitoru, proistekao je IZVEŠTAJ O POLUINDUSTRIJSKIM ISPITIVANJIMA POLIMETALIČNE RUDE LEŽIŠTA „PODVIROVI I CONJEV KAMEN“ – BOSILMETA
Obtaining fillers based on limestone from deposit “Ristova ponta”-Ulcinj for applications in various industries
No full textPaper presents results of investigations of using limestone as filler. Micronization methods, granulometric composition, oil and water absorption and degree of whiteness were investigated, and chemical and thermal analyses were performed. Physico chemical properties classified, by quality, this limestone for use as filler in the following industries: paints and coatings; rubber and plastic; glass; foundry; sugar, metallurgy and paper production. Due to low degree of whiteness and high content of MgO, heavy metals, and biogenic elements this limestone cannot be used in folowing industries: pharmaceutical and cosmetics, in fertilizers, in production of cattle feed and for neutralization of acidic soils
Obtaining fillers based on limestone from deposit ”Darza”-Ulcinj for applications in various industries
No full textThis paper presents results of investigations of the possibility of using “Darza”-Ulcinj limestone (Republic Montenegro) as filler in various industry branches. Micronization methods, granulometric composition, oil and water absorption and degree of whiteness were investigated, and chemical and thermal analyses (DT/TG) were performed. Physico-chemical properties of this limestone classify it among the poor in quality carbonate raw materials with relatively low CaCO3 content of 92.93%, as well as relatively high MgO content of 3.11% (6.53% content of MgCO3) and low silicate content (SiO2 0.186%). Its quality satisfies requirements of standards on using of calcium carbonate as filler in industry of paints and coatings; and in foundry industry. Due to the low degree of whiteness (85.10%) and low content of CaCO3 (92.93%) „Darza” limestone cannot be used in pharmaceutical and cosmetics industry, paper industry. Due to relatively low content of CaCO 3 and high content of MgO, “Darza” limestone cannot be used in: rubber and PVC industry; sugar industry glass industry; production of mineral fertilizers; production of cattle feed; for neutralization of acidic soils and metallurgy. Relatively high content of heavy metals Pb (30 ppm), Ni (17 ppm) and Cd (3 ppm), as well as biogenic elements Cu (8 ppm) and Fe (375 ppm), additionally limits the application of this material in production of cattle feed and for neutralization of acidic soils
Design of microstructure of ceramics based on waste fly ash and clay
No full textCeramics microstructure was designed using waste flay ash (REK Bitola, Macedonia) and clay. The raw materials were characterized from chemical, mineralogical and thermal aspect. The ceramics was designed using the granulation less than 0.063 mm. The clay content varied from 10 to 90 wt.%. The consolidation of the compacts was realized at pressure of 45 MPa and sintering at different temperatures (900, 1000, 1500 and 1100 oC/1h, heating rate of 10oC/min).
The designed microstructure of the composite with composition 60wt% clay and 40wt% fly ash sintered at 1100oC/1h was found as optimal regarding to its properties: density- 2.089g/cm2; water absorption- 7.02%, bending strength – 50.47 MPa and E-modulus - 25,35GPa. Technical coefficient of thermal expansion was α20-600=7.03x10-6/oC
Pyrolysis of lignocellulosic biomass
No full textLimitations and exhaustions of energy sources (e.g. fossil fuels) have resulted in taking major steps in sustainable plans for rational using of resources that exist today and finding new, alternative energy resources. Biomass is renewable energy resource which can be grown where climatic conditions are appropriate. Bio-oil as one of the major products obtained from the pyrolysis of lignocellulosic biomass has a number of industrial applications. After upgrading it is possible to use biooil as fuel for transport. Pyrolysis temperature is the main factor that affects the transfer of heavy metals in the volatile fraction of pyrolysis
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