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Acid tar (AT) is a distinct black viscous waste from the petrochemical industry that retains hazardous characteristics decades after creation. It is defined as an emulsion of various organic compounds, sulfuric acid, and water. Due to specific chemical composition and physical properties, the best available technique for the treatment of AT is not determined. This paper investigates the treatment of AT by CaO, resulting in its complete physicochemical transformation into a dry powder with the characteristics of inorganic material. Waste characterization of AT and obtained powder (including metals, PAH, BTEX, total hydrocarbon content, and EN12457-4 leaching test), their comparative FT-IR and SEM–EDS analyses, and XRD analysis of the powder revealed that the transformation is a complex process involving Ca(OH)2 formation, evaporation of water and BTEX, and degradation of aromatic and unsaturated hydrocarbons. The remained organic phase is encapsulated under Ca(OH)2 and CaCO3 layers forming “organic core—inorganic shell” micron-sized particles, rendering the powder suitable for further treatment. This was confirmed by solidification/stabilization treatment of AT and obtained powder using the same amount of cement and pozzolanic binder. In contrast to AT solidificates, the powder solidificates possess unconfined compressive strength above the required value and characteristics of inert waste.

Tehničko rešenje obuhvata procenu količine otpadne vode i koncentracije zagađujućih materija (ukupne suspendovane čestice, koncentracije sulfata i metala – Fe, Pb, Zn, Cd, As, Sb, Cu, Ni) u zavisnosti od mesta nastanka; definisanje tretmana otpadnih voda u skladu sa najbolje dostupnim tehnikama za oblast primarne i sekundarne industrije olova i izbor inovativnog rešenja tretmana otpadnih voda čijom se primenom obezbeđuje zadovoljavajući kvalitet prečišćene vode za ponovno korišćenje u radu predmetnog kompleksa (sistem recirkulacije tehničke vode) ili ispuštanje u okolinu. Tehničko rešenje za tehnološki postupak tretmana otpadnih voda nastalih na predmetnom postrojenju u Zajači uključuje hemijsko taloženje metala u obliku hidroksida (Fe, Pb i Cu) i sulfata (SO42-) u obliku kalcijum-sulfata (CaSO4) dodavanjem 15 mas.% rastvora kalcijum-hidroksida (Ca(OH)2) i adsorpciju zaostalih jona metala (Zn, Cd, Ni, Sb i As) na prirodnom/modifikovanom zeolitu. Inovativni deo tehničkog rešenja jeste simultana modifikacija prirodnog zeolita rastvorom soli gvožđe(III)-hlorid (FeCl3) koji se ujedno koristi kao koagulant u tretmanu otpadne vode. Fe–modifikovani zeolit ima izražen afinitet prema katjonima metala zaostalim u rastvoru nakon prvog stepena prečišćavanja, kao i afinitet prema oksoanjonima arsena i antimona koji se ne mogu ukloniti metodom taloženja hidroksida. Primena inovativnog tehničkog rešenja ima za cilj pozitivan uticaj na tehno-ekonomsku analizu procesa, koji se ogleda u povećanju efikasnosti postupka prečišćavanja uz smanjenje broja procesnih koraka, smanjenje upotrebe hemijskih reagenasa i primeni ekonomski isplativog i lako dostupnog prirodnog zeolita koji bi omogućio efikasno uklanjanje katjona metala, ali i oksoanjona antimona i arsena. Efikasnost inovativne tehnologije je eksperimentalno potvrđena.

Low-cost and easily available natural zeolite is a promising adsorbent for metal ions removal in wastewater treatment. The possibility of using zeolitic tuff from Serbia in the form of Na-enriched natural zeolite (Na-Z) for the adsorption of Pb2+, Zn2+, Cu2+, and Ni2+ions from wastewater was investigated in the presented paper. The research included Na-Z characterization and determination of adsorption kinetics in individual ion adsorption tests using Weber-Morris intraparticle diffusion model, non-linear pseudo-first-order (PFO), pseudo-second-order (PSO) and mixed-order (MO) kinetic models. The results indicate that the adsorption processes of metal ions on Na-Z are complex processes dominated by multiple rate-limiting mechanisms and best defined by the MO model. The mechanisms of ion diffusion and adsorption to active sites are equally represented in the Pb2+adsorption process. The mechanism of ion adsorption on the active sites is the rate-limiting step in the Zn2+adsorption process, while in the case of the Cu2+and Ni2+adsorption ion diffusion is the rate-limiting kinetic mechanism. Within the MO model, the PFO rate (external/internal diffusion) and the PSO rate (adsorption on active sites) were calculated and results wereapplied to a multicomponent wastewater sample in order to determine and explain the adsorption efficiency in wastewater treatment. The results show that the rate of adsorption of individual metal ions and the efficiency of ion removal from a multicomponent wastewater sample are influenced by several factors including the radius of the hydrated ion and the free energy of hydration. The achieved removal of metal ions by Na-Z is Pb2+(89%) > Cu2+(72%) > Zn2+(61%) > Ni2+(58%) and defines Na-enriched naturalzeolite as an effective adsorbent in wastewater treatment.

Porozna keramika sa industrijskog aspekta predstavlja značajan materijal, međutim, za njenu pripremu se još uvek traže ekonomski i tehnološki prihvatljiva rešenja. Kontrola poroznosti predstavlja ključan korak u postizanju željenih svojstava za određenu primenu. U cilju dobijanja multiporozne keramike u ovom radu korišćena je kaolinska glina i polistirenske perle kao organska žrtvena faza. Uzorci su nakon mešanja sinterovani na 1050 oC tokom 1 h. Karakterizacija je obuhvatila infracrvenu spektroskopiju sa Furijeovom transformacijom (FTIR), kenirajuću elektronsku mikroskopiju (SEM), rendgensku difrakcionu analizu (XRPD), elementnu CHNS analizu i ispitivanje pritisne čvrstoće. Analiza dobijenih rezultata pokazala je da se hijerarhijski uređena, multiporozna keramika, odgovarajućih mehaničkih svojstava može pripremiti u prisustvu organske komponente čijim sagorevanjem tokom sinterovanja zaostaju pore različitih dimenzija., From an industrial point of view, porous ceramics represent an important material, however, economically and technologically acceptable solutions are still being sought for its preparation. Porosity control is a key step in achieving the desired properties for a specific application. In order to obtain multiporous ceramics, in this work, kaolin clay and polystyrene beads were used as organic sacrificial phase. After mixing, the samples were sintered at 1050 oC for 1 h. Characterization included Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), X-ray diffraction analysis (XRPD), elemental CHNS analysis and compressive strength investigations. The analysis of the obtained results showed that hierarchically ordered, multiporous ceramics, with appropriate mechanical properties can be prepared in the presence of an organic component whose burnout during sintering leaves behind pores of different dimensions.

More than 90% of lead produced in Europe comes from secondary lead flows, of which 85% is attributed to waste lead-acid batteries (LAB). The main technological approach for LAB processing implies pyrometallurgy by which 100–400 kg of waste slag (WS) is generated per 1 ton of produced metallic lead. Due to recycling process parameters, generated WS has great potential for releasing toxic elements contributing to environmental pollution [1]. Namely, the most common flux in the recycling process is sodium-based (Na2CO3) when alkali lead waste slag (ALWS) is generated, characterized as hazardous due to its physical-chemical characteristics: high leachability, hygroscopic and pulverized nature and, ultimately, instability [2,3]. Therefore, ALWS treatment prior to disposal should be considered an integral part of waste LAB treatment systems. Immobilization of toxic elements contained in slag is crucial and can be achieved by stabilization/solidification processes (S/S) as one of the most widely used technologies in the treatment of heavy metal-containing wastes for final disposal or utilization. In this research, ALWS generated in the waste LAB recycling is used to determine the S/S process efficiency as a function of the added binder amount (cement, in the range of 5 – 10 %), pre-treatment (the removal of water-soluble compounds), and activator addition (MgO). The liquid to solid (L/S) ratio was 1/4 in all S/S experiments. The basic parameters for the effectiveness assessments were compressive strength (UCS) and pollutants leaching (Method 1311 Toxicity characteristic leaching procedure, TCLP). ALWS containing 3.5 Pb, 15.5 Na, 14.0 S, and 24.7 Fe was mixed with cement and water. The results of UCS showed that all produced solidificates exceeded the required value of 0.35 MPa [4], yet the mixture containing 7.5 % of the cement has the best mechanical properties (2.1 MPa). This sample was further analyzed and the TCLP results showed that the Pb concentration exceeds the li

More than 90 % of lead produced in Europe comes from secondary lead flows, of which 85 % is attributed to waste lead-acid batteries (LAB). The main technological approach for LAB processing implies pyrometallurgy by which 100–400 kg of waste slag (WS) is generated per 1 ton of produced metallic lead. Due to recycling process parameters, generated WS has great potential for releasing toxic elements contributing to environmental pollution [1]. Namely, the most common flux in the recycling process is sodium-based (Na2CO3) when alkali lead waste slag (ALWS) is generated, characterized as hazardous due to its physical-chemical characteristics: high leachability, hygroscopic and pulverized nature and, ultimately, instability [2,3]. Therefore, ALWS treatment prior to disposal should be considered an integral part of waste LAB treatment systems. Immobilization of toxic elements contained in slag is crucial and can be achieved by stabilization/solidification processes (S/S) as one of the most widely used technologies in the treatment of heavy metal containing wastes for final disposal or utilization. In this research, ALWS generated in the waste LAB recycling is used to determine the S/S process efficiency as a function of the added binder amount (cement, in the range of 5 – 10 %), pre-treatment (the removal of water-soluble compounds), and activator addition (MgO). The liquid to solid (L/S) ratio was 1/4 in all S/S experiments. The basic parameters for the effectiveness assessments were compressive strength (UCS) and pollutants leaching (Method 1311 Toxicity characteristic leaching procedure, TCLP). The conclusion is that, contrary to the pre-treatment process, the addition of MgO has an overall positive effect on the S/S process of ALSW, ensuring both mechanical and chemical stability. This ALWS solidificate, obtained through the S/S process by using MgO as an activator, is safe for disposal, according to environmental regulations.

Natural zeolite is a good sorbent for many cations due to its specific porous structure. The degree of sorption efficiency depends on the cation type and the availability of exchange positions in the zeolite lattice. The aim of this work is to examine the synthesis possibility of a new adsorbent based on natural zeolite and hydroxyapatite. The adsorbent was prepared mechanochemically by using clinoptilolite-rich zeolite tuff from the Slanci deposit (Serbia) and hydroxyapatite obtained by the hydrothermal process. The milling process was performed in a ball mill and optimized regarding contact time and milling speed. For the synthesis of zeolite/hydroxyapatite adsorbent (ZHAp), optimal values for these two parameters were 10 min and 250 rpm, respectively. The resulting sample ZHAp was characterized by X-ray powder diffraction, thermal analysis and scanning electron microscopy. Diffraction analysis of the ZHAp confirmed the presence of the most abundant mineral in zeolite tuff - clinoptilolite and hydroxyapatite. Needle-like crystals of hydroxyapatite on the clinoptilolite surface are observed in SEM images. Zeolite/hydroxyapatite sample is thermally stable at 800 °C. Adsorption properties of ZHAp were examined for nickel and chromium ions, towards which natural zeolite shows a low affinity. The presence of hydroxyapatite on the zeolite surface led to an increase in the adsorption capacity more than two times for both tested ions compared to the initial zeolite tuff.

The aim of this study was to investigate a possibility of synthesis of porous ceramics with controlled open porosity, which could be used as sorbents and catalyst supports. Two organic additives were used to obtain open porosity: polystyrene beads and cellulose fibers, which are mixed with kaolin clay powder and the appropriate water content. Samples were sintered at 1050 oC for 1 h. Characterization of the obtained products included X-ray powder diffraction analysis (XRPD), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and elemental CHNS analysis. In addition, porosity was examined by quantification of visual information. The specific surface areas were determined by the Brunauer–Emmett–Teller (BET) method. Also, density and compressive strength of the obtained samples were assessed. It was determined that by sintering, the organic component completely leaves the system. For samples prepared with polystyrene beads and with cellulose fibers, satisfactory mechanical properties were obtained: compressive strengths were 1.42 and 1.56 MPa, respectively. It was noted that significantly higher open porosity was obtained by using polystyrene beads as a sacrificial template (porosity of ~56 %) instead of cellulose fibers (porosity of ~6 %).

The aim of this study was to investigate a possibility of synthesis of porous ceramics with controlled open porosity, which could be used as sorbents and catalyst supports. Two organic additives were used to obtain open porosity: polystyrene beads and cellulose fibers, which are mixed with kaolin clay powder and the appropriate water content. Samples were sintered at 1050 oC for 1 h. Characterization of the obtained products included X-ray powder diffraction analysis (XRPD), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and elemental CHNS analysis. In addition, porosity was examined by quantification of visual information. The specific surface areas were determined by the Brunauer–Emmett–Teller (BET) method. Also, density and compressive strength of the obtained samples were assessed. It was determined that by sintering, the organic component completely leaves the system. For samples prepared with polystyrene beads and with cellulose fibers, satisfactory mechanical properties were obtained: compressive strengths were 1.42 and 1.56 MPa, respectively. It was noted that significantly higher open porosity was obtained by using polystyrene beads as a sacrificial template (porosity of ~56 %) instead of cellulose fibers (porosity of ~6 %).

In order to reflect possible issues in future sole e-waste processing, an electrolyte of complex chemical composition reflecting system of sole e-waste processing was obtained by following a specially designed pyro-electrometallurgical method. The obtained non-standard electrolyte was further used for the purpose of comprehensive metal interference evaluation on the copper solvent extraction (SX) process. Optimization of the process included a variation of several process parameters, allowing determination of the effect of the most abundant and potentially the most influential impurities (Ni, Sn, Fe, and Zn) and 14 other trace elements. Moreover, comparing three commercial extractants of different active chelating groups, it was determined that branched aldoxime reagent is favorable for Cu extraction from the chemically complex system, as can be expected in future e-waste recycling. The results of this study showed that, under optimal conditions of 20 vol.% extractant concentration, feed pH 1.5, O/A ratio 3, and 10-min phase contact time, 88.1% of one stage Cu extraction was achieved. Co-extraction of the Fe, Zn, Ni, and Sn was under 8%, while Pb and trace elements were negligible. Optimal conditions (H2SO4 180 g/L, O/A = 2, and contact time 5 min) enabled 95.3% Cu stripping and under 6% of the most influential impurities. In addition, an impurity monitoring and distribution methodology enabled a better understanding and design of the process for the more efficient valorization of metals from e-waste.

This paper presents thermochemical synthesis of copper/alumina nanocomposites in a Cu-Al(2)O(3)system with 1-2.5 wt.% of alumina and their characterization, which included: transmission electron microscopy: focused ion beam (FIB), analytical electron microscopy (AEM) and high resolution transmission electron microscopy (HRTEM). Thermodynamic analysis was used to study the formation mechanism of desirable products during drying, thermal decomposition and reduction processes. Upon synthesis of powders, samples were cold pressed (2 GPa) in tools dimension 8 x 32 x 2 mm and sintered at temperatures within the range 800-1000 degrees C for 15 to 120 min in a hydrogen atmosphere. Results of characterization showed that dispersion-strengthened compacts could be produced by sintering of thermo-chemically prepared Cu-Al(2)O(3)powders with properties suitable for material application, such as a contact material exhibiting high strength and high electrical conductivity at the same time. Additional research was carried out in order to analyze the application of the obtained nanocomposite powders for the synthesis of copper/alumina nanocomposites by a new method, which is a combination of a thermochemical procedure and mechanical alloying. The measured values of an electric conductivity and hardness were compared with ones in literature, confirming an advantage of the proposed combined strategy.

This paper describes the synthesis of tungsten disulfide (WS 2 ) powder by the sulfurization of tungsten trioxide (WO 3 ) particles in the presence of additive potassium carbonate (K 2 CO 3 ) in nitrogen (N 2 ) atmosphere, first at lower temperature (200 ◦ C) and followed by reduction at higher temperature (900 ◦ C). In addition, the ultrasonic spray pyrolysis of ammonium meta-tungstate hydrate (AMT) was used for the production of WO 3 particles at 650 ◦ C in air. The HSC Chemistry® software package 9.0 was used for the analysis of chemistry and thermodynamic parameters of the processes for WS 2 powder synthesis. The crystalline structure and phase composition of all synthesized powders were analyzed by X-ray diffraction (XRD) measurements. The morphology and chemical composition of these samples were examined by scanning electron microscopy (SEM) combined with energy dispersive X-ray analysis (EDX).

The aim of this research was to study the effect of graphite addition in the process of synthesis of tribological materials based on tin sulphides. The tin sulphides powders were synthesized from selected precursors by pyrometallurgical method in rotary tilting tube furnace. The thermodynamic parameters of the synthesis were determined using HSC Chemistry software modelling package. In addition, the synthesis process was also characterized by the thermal analysis method: simultaneous differential scanning calorimetry and thermogravimetry (DCS-TGA). The characterization of the synthesized tin sulphides powders included analysis of chemical composition by optical emission spectroscopy, phase composition identification by X-ray diffraction (XRD) and examination of morphology, as well as elemental composition by scanning electron microscopy (SEM) with energy-dispersive spectroscopy (EDS). The hexagonal SnS2 and orthorhombic Sn2S3 phases were formed after the thermal treatment of starting powders in nitrogen atmosphere. The obtained results indicate the positive effects of the graphite addition which enables the synthesis of tin sulphide powders with appropriate content of sulphide phases with minimal loss of sulphur.

Reuse of waste is one of the main principles of sustainable development and circular economy. Secondary alkaline lead slag is a hazardous waste generated in the recycling process of lead-acid batteries that may be suitable in construction materials. The environmental impact of the use of lead slag as a partial replacement of fine aggregates in the cement-based stabilization/solidification (S/S) process for the preparation of concrete was studied in this paper. Solidified products containing 10%, 15%, 20%, and 25% slag were laboratory tested by unconfined compressive strength (UCS) analyses and the Toxicity Characteristic Leaching Procedure (TCLP). At the same time, the leachability of toxic elements from solidified products with a high percent of slag was evaluated under environmental conditions for during one year. The results of the UCS and TCLP indicated that utilization of this type of slag in cement-based applications may be justified with its controlled addition. However, the described application of the slag was disputed due to the high release of As under high alkaline environmental conditions. Eh-pH analyses and the geochemical modeling using the software PHREEQC were evaluated, as well as the mechanism of pollutant (Pb, As) immobilization (precipitation, adsorption) as a function of pH conditions.

This paper describes the synthesis of tungsten disulfide (WS2) powder by the sulfurization of tungsten trioxide (WO3) particles in the presence of additive potassium carbonate (K2CO3) in nitrogen (N-2) atmosphere, first at lower temperature (200 degrees C) and followed by reduction at higher temperature (900 degrees C). In addition, the ultrasonic spray pyrolysis of ammonium meta-tungstate hydrate (AMT) was used for the production of WO3 particles at 650 degrees C in air. The HSC ChemistryA (R) software package 9.0 was used for the analysis of chemistry and thermodynamic parameters of the processes for WS2 powder synthesis. The crystalline structure and phase composition of all synthesized powders were analyzed by X-ray diffraction (XRD) measurements. The morphology and chemical composition of these samples were examined by scanning electron microscopy (SEM) combined with energy dispersive X-ray analysis (EDX).

This research aimed to develop a novel catalyst based on WO3/ZrSiO4 system for halogenated hydrocarbons processing. The production method of this catalyst involved extrusion and as such was simplified compared to thermo-chemical synthesis routes. It had a reduced number of process stages and a lower environmental impact at the same time. In order to examine the phase composition of the catalyst after sintering at 800 degrees C, the XRD analysis was carried out. The catalyst was then tested in chlorodifluoromethane dehalogenation process on laboratory scale at temperatures of 300, 400 and 500 degrees C in the presence of water vapor. Catalyst achieves high dehalogenation efficiencies of 88.6, 95.9, and 99.5 % for each of the process temperatures, respectively. Obtained results are in the range with those achieved by using thermo-chemically prepared dehalogenation catalysts.

Proces stabilizacije/solidifikacije (S/S) se smatra najboljom dostupnom tehnikom za tretman industrijskog muljevitog i čvrstog otpada. U okviru disertacije ispitivan je razvoj i optimizacija S/S procesa otpadnog mulja koji nastaje tretmanom otpadne vode iz primarne topionice bakra, kao i stabilizacija klinkera tokom tretmana otpadnih muljeva iz hidrometaluškog procesa dobijanja cinka koji se odlikuju visokim sadržajem osnovnih i toksičnih metala (Cu, Zn, Pb, Ni i As). Optimizacija S/S procesa otpadnog mulja iz primarne topionice bakra je vršena variranjem odnosa mulj/agens za stabilizaciju i sastava agensa. Kao agens za stabilizaciju ispitivan je leteći pepeo u smešama sa kalcijum(II)-hidroksidom i kompozitnim portland cementom. Efikasnost S/S procesa je određena merenjem pritisne čvrstoće i stabilnosti solidifikata na luženje kontaminenata upotrebom dva standardna testa: TCLP i EN 12457-4. Kako su primenjeni standardni testovi dali različitu klasifikaciju pojedinih solidifikata kao opasnog ili neopasnog otpada, u disertaciji je predložena i primenjena postavka dugoročnog testa luženja pod realnim uslovima sredine koji se sastoji u izlaganju solidifikata uticaju atmosferalija tokom godinu dana i skupljanju drenažne vode tokom zimskog i letnjeg perioda, a u cilju određivanja realnije ocene stabilnosti tretiranog otpada. Utvrđeno je da nivo izluženja kontaminenata zavisi od puferskog kapaciteta solidifikata, određenog primenom ANC testa. Faze u strukturi solidifikata koje su uzrokovale razlike u pritisnoj čvrstoći i stabilnosti na luženje između dobijenih solidifikata nisu otkrivene tokom mineraloške analize primenom XRD metode usled generalno amorfne strukture solidifikovane matrice. Diferencijalna ANC analiza (d-ANC) predstavlja efikasnu alternativu u ispitivanju strukture solidifikata, a u disertaciji su njeni rezultati upareni sa Eh-pH dijagramima što predstavlja novitet u primeni ove analize. Primena modifikovane d-ANC analize je determinisala prisustvo neizreago, Stabilization and solidification process is considered to be the best available technique for the treatment of industrial waste sludge and solid waste. This PhD thesis presents investigations of development and optimization of the S/S process of waste sludge generated during the wastewater treatment in primary copper smelter, as well as the stabilization process of clinker formed during the treatment of waste sludges with copper content from hydrometallurgical zinc processing which are characterized by a high content of base and toxic metals (Cu, Zn, Pb, Ni i As). The optimization of the S/S process of wastewater treatment sludge from primary copper smelter is done by varying the ratio sludge/binder and the composition of the binder (the agent for stabilization). Fly ash (FA), individually or in mixtures with hydrated lime (HL) and composite Portland cement (PC), was investigated as the stabilization agent. The efficiency of the S/S process is determined by measuring the unconfined compressive strength (UCS) and leaching stability of solidificates by using two standard leaching tests: TCLP and EN 12457-4. The two leaching tests gave different classification of the same treated waste as hazardous or non-hazardous. For that reason the setting of a long-term leaching test under the real environmental conditions is proposed and applied within the PhD thesis. The test includes exposure of solidificates to the effect of atmospheric water during one year and collection of drainage water during the summer and winter season in order to determine a more realistic assessment of the stability of the treated waste. It is determined that the leaching level of contaminants depends on the buffer capacity of the solidificates and it was analyzed by using the ANC test. Phases in the solidified structure that caused the differences in the UCS and leaching stability between the obtained solidificates were not detected in the mineralogical analysis done by the XRD method due to the gene

Stabilization and solidification process is considered to be the best available technique for the treatment of industrial waste sludge and solid waste. This PhD thesis presents investigations of development and optimization of the S/S process of waste sludge generated during the wastewater treatment in primary copper smelter, as well as the stabilization process of clinker formed during the treatment of waste sludges with copper content from hydrometallurgical zinc processing which are characterized by a high content of base and toxic metals (Cu, Zn, Pb, Ni i As). The optimization of the S/S process of wastewater treatment sludge from primary copper smelter is done by varying the ratio sludge/binder and the composition of the binder (the agent for stabilization). Fly ash (FA), individually or in mixtures with hydrated lime (HL) and composite Portland cement (PC), was investigated as the stabilization agent. The efficiency of the S/S process is determined by measuring the unconfined compressive strength (UCS) and leaching stability of solidificates by using two standard leaching tests: TCLP and EN 12457-4. The two leaching tests gave different classification of the same treated waste as hazardous or non-hazardous. For that reason the setting of a long-term leaching test under the real environmental conditions is proposed and applied within the PhD thesis. The test includes exposure of solidificates to the effect of atmospheric water during one year and collection of drainage water during the summer and winter season in order to determine a more realistic assessment of the stability of the treated waste. It is determined that the leaching level of contaminants depends on the buffer capacity of the solidificates and it was analyzed by using the ANC test. Phases in the solidified structure that caused the differences in the UCS and leaching stability between the obtained solidificates were not detected in the mineralogical analysis done by the XRD method due to the gene, Proces stabilizacije/solidifikacije (S/S) se smatra najboljom dostupnom tehnikom za tretman industrijskog muljevitog i čvrstog otpada. U okviru disertacije ispitivan je razvoj i optimizacija S/S procesa otpadnog mulja koji nastaje tretmanom otpadne vode iz primarne topionice bakra, kao i stabilizacija klinkera tokom tretmana otpadnih muljeva iz hidrometaluškog procesa dobijanja cinka koji se odlikuju visokim sadržajem osnovnih i toksičnih metala (Cu, Zn, Pb, Ni i As). Optimizacija S/S procesa otpadnog mulja iz primarne topionice bakra je vršena variranjem odnosa mulj/agens za stabilizaciju i sastava agensa. Kao agens za stabilizaciju ispitivan je leteći pepeo u smešama sa kalcijum(II)-hidroksidom i kompozitnim portland cementom. Efikasnost S/S procesa je određena merenjem pritisne čvrstoće i stabilnosti solidifikata na luženje kontaminenata upotrebom dva standardna testa: TCLP i EN 12457-4. Kako su primenjeni standardni testovi dali različitu klasifikaciju pojedinih solidifikata kao opasnog ili neopasnog otpada, u disertaciji je predložena i primenjena postavka dugoročnog testa luženja pod realnim uslovima sredine koji se sastoji u izlaganju solidifikata uticaju atmosferalija tokom godinu dana i skupljanju drenažne vode tokom zimskog i letnjeg perioda, a u cilju određivanja realnije ocene stabilnosti tretiranog otpada. Utvrđeno je da nivo izluženja kontaminenata zavisi od puferskog kapaciteta solidifikata, određenog primenom ANC testa. Faze u strukturi solidifikata koje su uzrokovale razlike u pritisnoj čvrstoći i stabilnosti na luženje između dobijenih solidifikata nisu otkrivene tokom mineraloške analize primenom XRD metode usled generalno amorfne strukture solidifikovane matrice. Diferencijalna ANC analiza (d-ANC) predstavlja efikasnu alternativu u ispitivanju strukture solidifikata, a u disertaciji su njeni rezultati upareni sa Eh-pH dijagramima što predstavlja novitet u primeni ove analize. Primena modifikovane d-ANC analize je determinisala prisustvo neizreago

This paper presents an experimentally-proved hydrometallurgical process for selective metals recovery from the waste-printed circuit boards (WPCBs) using a combination of conventional and time-saving methods: leaching, cementation, precipitation, reduction and electrowinning. According to the results obtained in the laboratory tests, 92.4% Cu, 98.5% Pb, 96.8% Ag and over 99% Au could be selectively leached and recovered using mineral acids: sulfuric, nitric and aqua regia. Problematic tin recovery was addressed with comprehensive theoretical and experimental work, so 55.4% of Sn could be recovered through the novel physical method, which consists of two-step phase separation. Based on the results, an integral hydrometallurgical route for selective base and precious metals recovery though consecutive steps, (i) Cu, (ii) Sn, (iii) Pb and Ag, and (iv) Au, was developed. The route was tested at scaled-up laboratory level, confirming feasibility of the process and efficiencies of metals recovery. According to the obtained results, the proposed hydrometallurgical route represents an innovative and promising method for selective metals recovery from WPCBs, particularly applicable in small scale hydrometallurgical environments, focused on medium and high grade WPCBs recycling.

Wide application of hard metals requires increased consumption of their constituents. Their high cost and scarcity impose the need for finding new, both ecologically and economically justified ways for their production. In presented research, on the basis of previous research, a review of an integrated technological procedure of recycling and valorization of useful components from hard metals secondary raw materials is given. Integrated procedure for processing of hard metal's waste enables the preparation of a wide range of powders with required properties, a high efficiency and reducing the duration of individual stages of procedures for their processing. Therefore, besides conservation of natural resources there are also significant economic and energetic benefits. The developed technological procedure is in service of sustainable development.