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Adsorption of copper ions from mining Wastewater using different mineral adsorbents
No full textU ovom radu ispitivana je mogucnost primene prirodnog zeolita-klinoptilolita iz nekoliko ležišta: “Zlatokop” Vranjska Banja, “Igroš Vidojevic” Brus i “Baia Mare” Rumunija za adsorpciju jona bakra iz vodenih rastvora, kao i iz otpadnih voda industrijskih sistema RTB Bor. Zbog velike koncentracije bakra u ovim otpadnim vodama, neophodno je da se pre ispuštanje u prirodne vodotokove sadržaj bakra smanji do dozvoljene vrednosti koncentracije od 1 mg dm-3. S druge strane, velika kolicina otpadne vode koja napušta industrijske sisteme u okviru RTB Bor, sadrži veliku kolicinu bakra koji potencijalno može da bude iskorišcen. Zato je u ovom radu adsorpcija izabrana kao metoda kojom je moguce postici regeneraciju adsorbenta i ponovo iskoristiti adsorbat. U radu je pokazano da se bakar iz otpadne vode može efikasno ukloniti adsorpcijom na prirodnom zeolitu kao i da se zasiceni adsorbent može regenerisati, a bakar dobijen regeneracijom vratiti u postupak proizvodnje. Ovo predstavlja efikasan nacin za valorizaciju bakra iz rudnickih otpadnih voda. S obzirom na nisku cenu i dostupnost prirodnog zeolita iz ležišta “Zlatokop” (Vranjska Banja), ovaj tuf je, nakon laboratorijskih ispitivanja, detaljno ispitan kao adsorbent u realnim uslovima. Predložena je optimalna tehnološka šema za uklanjanje bakra iz otpadnih voda RTB Bor u diskontinualnim i kontinualnim sistemima. Ispitivanja u diskontinualnim sistemima pokazala su da efikasnost adsorpcije zavisi od koncentracije bakra u pocetnom rastvoru, vrednosti pH, krupnoce zrna adsorbenta kao i odnosa cvrsto/tecno. Proces adsorpcije u diskontinualnom sistemu sledi Hoov model pseudo-drugog reda, konstanta brzine opada sa povecanjem koncentracije bakra i vrednosti pH. Proces adsorpcije nije ogranicen procesima difuzije...This doctoral thesis presents the possibility of the use of natural zeolite-clinoptilolite from several deposits: “Zlatokop” (Vranjska Banja), “Igroš Vidojevic” (Brus) and “Baia Mare” (Romania) in removal of copper from aqueous solutions and real wastewaters - from the Mining and Smelting Combine Bor (RTB Bor). Due to a high Cu(II) concentration in the wastewaters of the RTB Bor reducing of copper level to the 1mg dm-3 and its reuse were the main goals in the selection of the wastewater treatment method. The adsorption was selected as a suitable method which can provide regeneration of the spent adsorbent and recovering of the adsorbed copper. The investigations have revealed that copper can be effectively removed from wastewaters by the adsorption using natural zeolite. The spent zeolite-based adsorbent can be regenerated allowing that the removed copper can be reused in the operational plant. Due to the local availability and low cost, natural zeolite from deposit “Zlatokop” (Vranjska Banja) has been, after laboratory investigations, selected for experiments with real wastewaters from the plant Cerovo. Optimal technological scheme for the copper removal is defined based on the investigations in a batch and a fixed bed system. The batch experiments indicated that the efficiency of the adsorption depends on initial Cu(II) concentration, pH, particle size of the adsorbent and the solid/liquid ratio. Kinetics study shows that the copper adsorption by the zeolite follows the Ho's model of pseudo second order. The rate constant decreases with increasing of the initial copper concentration and pH. Diffusion processes have not been found to influence the adsorption..
Influence of clay organic modifier on the morphology and performance of poly(epsilon-caprolactone)/clay nanocomposites
No full textTwo series of poly(epsilon-caprolactone) poly(oxepan-2-one) nanocomposites with different organo-modified clays (1 to 8 wt. %) were prepared by the solution casting method. Organoclays with polar (Cloisite (R) C30B) and nonpolar (Cloisite (R) C 15A) organic modifiers and with different miscibility with the poly(epsilon-caprolactone) matrix were chosen. Exfoliated and/or intercalated structures of the nanocomposite were obtained using high dilution and ultrasonic treatment for the preparation of the composite. The effects of the surface modification and clay content on the morphology, and mechanical and thermal properties of the nanocomposites were studied. Scanning electron microscopy excluded the formation of microcomposites. The wide-angle X-ray diffraction analysis revealed that the tendency toward exfoliated structures was higher with Cloisite (R) C30B, which had better miscibility with poly(epsilon-caprolactone) matrix, than with Cloisite (R) Cl 5A. Differences in the sizes of the spherulites and morphology between two series of the nanocomposites were observed by optical microscopy performed on as-cast films. The enthalpies of fusion and degrees of crystallinity were higher for the nanocomposites than for the neat poly(epsilon-caprolactone) and increased with clay loading in both series, because of the nucleating effect of the clay. The decreased thermal stability of the nanocomposites was ascribed to the thermal instability of the organic modifiers of the clays. The Halpin-Tsai model was used to compare the theoretically predicted values of the Young's modulus with the ones experimentally obtained in tensile tests
Metal pollution determined by pollution indices for sea grass p. Oceanica and surface sediments
No full textConcentrations of Fe, Mn, Cu, Zn, Pb, Ni, Co, As, Co, and Hg in the sea grass Posidonia oceanica and surface sediment samples were determined. Together with P. oceanica, surface sediment samples were collected at eight locations in the major demographic, tourist and port areas along the Montenegrin coast to assess metal pollution. The metal pollution index (MPI) and metal enrichment factor (EF) were calculated and used to evaluate the impact of heavy metals in the surface sediment on P. oceanica. The sediment MPI and EF values were lower than these values in P. oceanica at the same locations. Since the surface sediment contained lower mean concentrations of Zn, Ni, Pb, Cd and Hg, than the sea grass P. oceanic, we concluded that the sea grass absorbed some metals from the seawater column
DTA study of the crystallization of Li2O-Nb2O5-SiO2-TiO2 glass
No full textIn this study, the crystallization of 30Li(2)O center dot 15Nb(2)O(5)center dot 50SiO(2)center dot 5TiO(2) (mol%) glass was examined. The parent glass was prepared by the standard melt quenching method, and the investigations were performed under non-isothermal and isothermal conditions using the DTA, XRD, SEM and EDS methods. The results revealed primary crystallization of this glass and the dendritic morphology of crystal growth. Three crystalline phases were formed in the glass matrix during crystallization, whereby LiNbO3 was formed as the primary phase, followed by Li2Si2O5 and SiO2 as the secondary. The surface and volume mechanisms of crystallization occur. The condition that both the mechanisms were dominant was determined. In the case of volume crystallization, the characteristics of the nucleation process were examined. The kinetic parameters of crystallization under different mechanisms of crystallization were determined
The Influence of Compaction Pressure on the Density and Electrical Properties of Cordierite-based Ceramics
No full textDue to its characteristics, cordierite, 2MgO center dot 2Al(2)O(3)center dot 5SiO(2), is a high-temperature ceramic material of a great scientific interest. Mechanical activation of the starting mixtures containing 5.00 mass% TiO2 was performed in a high-energy ball mill for 10 minutes. The compaction pressure varied from 0.5 to 6tcm(-2) (49-588 MPa). The sintering process was performed at 1350 degrees C for four hours in the air atmosphere. The phase composition of the activated and sintered samples was analyzed using X-ray diffraction. Scanning electron microscopy was used to analyze the microstructure of both compacted and sintered samples. The authors have investigated the influence of compaction pressure on the sintered samples and their electrical properties
DTA and IR study of lithium germanate phosphate glass
No full textDTA and IR data collected for 22.5 Li2O·10 Al2O3·30GeO2·37.5P2O5 (mol%) glass sample were reported and discussed. The ease of glass formation has been studied. It was determined that the DTA exothermal temperature peaks revealed the crystallization of LiGe2(PO4)3 and GeO2 phases. The value of Avrami exponent indicates that the LiGe2(PO4)3 phase has three-dimensional growth
Activation of phosphates for aplication in composite ceramic materials
No full textThe aim of this investigation was to increase the reactivity of comminuted phosphate ore for application in composite ceramic materials. The vibratory and planetary mills were used as mechanical activators during experimental research. The obtained results highlighted the presence of both amorphous and crystallized forms appearing in the observed phosphate ore mixture due to the specific genetic conditions which rarely occur in deposits. The heterogenic composition of the ore useful phosphoric part gave optimal results during the leaching test. For the first time, the experiments of phosphate mechano-chemical activation from Lisina ore deposit were performed in order to improve its reactivity
Quality and use of materials based on limestone „Dobar kamen“ Aranđelovac
No full textThis paper presents the quality and applicability of certain products, based on limestone from the site "Cancar", which is processed in "Dobar kamen" doo Arandjelovac. It can be seen from the results that the products are intended for the rubber and PVC, and PVC floors meet the prescribed quality standards SRPS
The possibility of applying contemporary flotation collectors to improve the technological effects of processing complex ore With pyrite high content from the upper layers deposit „Veliki Krivelj“
No full textThis paper presents part of a complex technological flotation investigations of copper ore from the upper layers deposit "Veliki Krivelj". Ore copper content is in the average range and sulfur content is significantly higher than usual. High content of sulfur derives from the increased content of mineral pyrite, which is very difficult to depress in flotation. Because of this, it is very difficult to control and to stabilize flotation process and technological results are below the planed one. In order to increase the flotation process efficiency and the copper concentrate quality, technological laboratory tests were conducted in the ITNMS Mineral Processing laboratory. Investigations were undertaken with an aim to examine the possibility of applying new collector structures (manuf. Flomin) which are implemented effectively for the ores with similar features in the World. The results in paper presents technological effects achieved by applying the tested collector and compared to the reagent that is used in the Flotation Plant "Veliki Krivelj ". Because of the good results, which showed that the tested collector has a high selectivity for copper, it was decided to be tested on an industrial scale
Flotation Extraction of Blue Water
No full textFlotation of ions and molecules represents a promising method of separating components from the solution, or in our case, gelled copper salt from the blue waters. The method of flotation of ions and molecules is basicly flotation extraction process which produces different concentration gradients of more component phase system. Different concentration gradients in the flotation extraction are due to the driving forces of the participating molecules driven by molecular interactions. More component phase system i.e. flotation pulp consists of water molecules of the solute, and a suitable reagent which has the role of connection of the liquid and gaseous phases dispersed in a biphasic system. Such a system leads to the interaction of the solute with a reagent to the formation of coagulated component in water as solvent. Separation in the polyphased system is in accordance with Van't Hoff-th equation, and spontaneously occurs in two-phase systems like gaseous-fluid, such as the system of flotation pulp. By use of the osmotic pressure in the columnn flotation machine comes to the separation of the flotation pulp to the heavy and light phase. This allows the molecules of water to form their natural distances which are only valid for molecules of pure water, apropos for heavy phase. Also, the solute forms it’s light phase, copper – surfactant salt as insoluble product. For some poliphase systems such as colloidal systems like in flotation process are sufficient atmospheric pressure conditions and for others solutions should be applied overpressure while being aerated. The paper presents the results of the research of flotation extraction of blue water i.e. copper solution content of 0.2 g/l. From the results, it is concluded that there is a possibility of purifying of blue water from copper mine tailings using the flotation extraction technology