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Industrial products are made from different materials, therefore existing metallurgical plants are not always able to adequately process them. Knowing the thermodynamic parameters, possibility and degree of removal of contamininats from the base metal in the recycling process can be predicted. Such approach facilitates a decisions about products design, selection of recycling technology, reduces contamination and increases the system resources. In addition, recycling process becomes more profitable, reducing energy costs and increasing environmental protection. In this way, the use of resources becomes more sustainable

Najznačajnije sekundarne sirovine kalaja su: otpadni beli limovi i međuprodukti njihove proizvodnje (kalajne šljake, mulj i sunđer), metalna ambalaža, olovo-kalajne šljake i legure, amortizovani hladnjaci iz automobilske industrije i dr. Tehnološki postupci njihove regeneracije obuhvataju dve osnovne faze: pripremu otpada i njegovu metaluršku preradu. Priprema metalne ambalaže za metaluršku preradu je veoma važna faza i obuhvata veliki broj tehnoloških operacija, kao sto su: sakupljanje, sortiranje, pranje, usitnjavanje, odmašćivanje i dr. Priprema otpadnog belog lima je jednostavnija usled lakšeg sakupljanja i manje zaprljanosti. Prerada pripremljenog otpada vrši se primenom postupka hlorovanja, elektrolitičkog rastvaranja i taloženja ili alkalnog luženja i elektrolize.Prerada kalajne šljake, mulja i sunđera vrši se primenom postupka redukcionog topljenja, a dobijeni sirovi kalaj rafiniše u više stupnjeva., Main resources of tin secondary raw materials are: residual tin-plates and by-products from their production (tin slags, sludges and sponges), metallic packings, lead-tin slags and alloys, amortised coolers from cars etc. The technological procedure for their processing includes two basic stages: pretreatment of the scrap and its metallurgical processing. The tin-plated cans pretreatment is a very important phase and it includes the following operations, cans collection, sorting, washing, crushing, warnish removal etc. Due to the easier collection and lower grade of impurities, the pretreatment of the waste tin plates is simpler in comparison with the tin-plated cans. The processing of the prepared scrap, can be carried out in two ways. In one way, the processing consists of chlorination treatment, electrolytical dissolution and precipitation, while in the other way alkaline leaching and electrolysis are employed. The processing of the tin slags, sludges and sponges can be carried out using reductional smelting process and refining of obtained secondary tin.

Metalni implantati za ortopedsku hirurgiju izrađuju se najčešće od nerđajućeg čelika, legura na bazi titana, kobalta ili hroma, koje imaju odlične konstrukcione i mehaničke osobine i otporne su na koroziju. Ipak, ovakvi implantati poldožni su lokalnoj koroziji u ljudskom telu jer je zapaženo prisustvo njihovih metalnih jona u okolnim tkivima i telesnim tečnostima. Da bi se iskoristila prednost njihovih mehaničkih karakteristika, a postigla biokompatibilnost, moguće je na njihovu površinu naneti bioinertnu ili čak bioaktivnu prevlaku. Hidroksiapatit je poznat po svom bioaktivnom ponašanju, koje duguje hemijskoj istovetnosti sa ljudskim kostima. Elektroforetska deopzicija je relativno stara tehnika, koja je ovde primenjena uz upotrebu novog materijala - nanostrukturnog hidroksiapatita, kako bi se dobile ravnomerne i kompaktne hidroksiapatitne prevlake i tako prevazišla ograničenja prethodno korišćenih visokotemperaturnih tehnika nanošenja prevlaka i problemi sa složenim oblikom metalnog supstrata. Prevlake nanostrukturnog hidroksiapatita eletroforetski su deponovane na peskiranu površinu uzoraka od nerđajućeg čelika 316LVM, pri konstantnom naponu, za različito vreme deponovanja, a zatim su sinterovane u atmosferi argona na 1000oC. Toplotna stabilnost HAp praha prvo je ocenjena DTA/TG analizom u temperaturnom intervalu 23oC-1000oC. Za mikrostrukturnu karakterizaciju prevlake korišćen je SEM, a za određivanje faznog sastava XRD analiza., Surgical metallic implants are usually made of stainless steel, titanium- and cobalt/chromium- based alloys which have superior structural and mechanical properties, and are corrosion resistant. Nevertheless, they are susceptible to local corrosion in the human body, releasing metal ions into the nearby body tissue and fluids. Keeping the advantage of their mechanical properties, their biocompatibility can be achieved through deposition the bioinert or even bioactive coating onto their surface. Hydroxyapatite is known by its bioactive behavior, originating from its chemical identity with human bones. The electrophoretic deposition is rather old technique used here with a novel nanostructured hydroxyapatite powder to obtain uniform and dense hydroxyapatite coatings, to overcome the restrictions of previously used high temperature coating techniques and to overcome the complex geometry metallic substrate problems. The coating of nanosized hydroxyapatite was electrophoretically deposited on blasted surface of stainless steel 316LVM samples at constant voltage, for different deposition times and subsequently sintered in argon atmosphere at 1000 oC. The HAp powder thermal stability was initially assessed using DTA-TG analyses over the temperature range of 23oC-1000oC. The microstructure characterization of the coating was accomplished using SEM, and phase composition was determined by XRD.

Hydroxyapatite is a widely used bioceramic material in implant coatings research because of its bioactive behavior when being deposited onto the metallic implant and compatibility with the human bones composition. The coating of nanosized hydroxyapatite was electrophoretically deposited on a blasted surface of stainless steel 316LVM samples at constant voltage, for different deposition times and subsequently sintered in both, vacuum and argon atmosphere, at 1040 and 1000°C, respectively. Although sintering temperatures needed to achieve highly dense coatings can cause HAp coating phase changes, the possibility to obtain a bioactive coating on 316LVM substrate, without the coatings phase changes due to the nature of the used stoichiometric nanostructured hydroxyapatite is presented in this work. The thermal stability of the used HAp powder was assessed by DTA-TG analyses over the temperature range of 23-1000°C, i.e., at the or nearby experimental sintering temperature. The microstructure characterization was accomplished using SEM, while phase composition was determined using XRD., Hidroksiapatit se široko koristi kao keramički biomaterijal zbog svoje bioaktivnosti koju ispoljava kada se u vidu prevlake nanese na metalni implantat, kao i zbog kompatibilnosti sa sastavom ljudskih kostiju. Prevlake hidroksiapatitnog nano-praha elektroforetski su istaložene na peskiranu površinu uzoraka od nerđajućeg 316LVM čelika, pri konstantnom naponu i za različito vreme taloženja, a potom sinterovane u vakuumu na 1040°C i u atmosferi argona na 1000°C. Premda visoke temperature sinterovanja, koje su neophodne kako bi se dobile kompaktne prevlake velike gustine, mogu da dovedu do faznih promena kod hidroksiapatita, u ovom radu je pokazano da je na supsrtatu od 316LVM čelika moguće dobiti bioaktivne prevlake u kojima nije došlo do fazne promene zahvaljujući prirodi korišćenog hidroskiapatitnog nano-praha stehiometrijskog sastava. Visokotemperaturna stabilnost korišćenog HAp praha potvrđena je DTA-TG analizom u temperaturnom opsegu 23-1000°C, tj. na temperaturama na kojima su rađeni eksperimenti sinterovanja. Mikrostrukturna karakterizacija nanetih prevlaka urađena je korišćenjem SEM, dok je za određivanje faznog sastava korišćena XRD analiza.

The relationships between electromagnetic frequency, microstructure and mechanical properties of continuous casting aluminum alloys were studied in this paper. EN AW 2024 and EN AW 2007 aluminum alloys ingots were produced by electromagnetic continuous casting process. The microstructure and mechanical properties of as cast ingots were examined. The results showed that electromagnetic field, especially low frequency electromagnetic field, greatly influenced the microstructure and mechanical properties of as cast ingots. The significant energy savings and product quality can be achieved by the application of a proper frequency.

Zinc is a widely applicable metal and therefore the different composition and form of zinc waste is generated. The most important waste material generated in production and processing of zinc is scrap metal of zinc and its alloys, as well as slag, dust and sludge from the production and processing of cathode zinc and zinc alloys. In terms of processing technology, there are different applied procedures depending on the type of raw material. The processing of waste zinc and its alloys is pyrometallurgical and it is based on remelting of dry and degreased raw materials, with alloying during melting to correct the composition. Zinc dust and sludge are processed by Waelz procedure, where the zinc-oxide is obtained and further being processed usually by hydrometallurgical procedure. The zinc and brass slag are grinded, followed by separation metal and oxide components. Large, predominantly metal fraction is being directly melted to obtain zinc or brass. Small, predominantly oxide phase is subjected to hydrometallurgical treatment for zinc valorization.

Hidroksiapatit se široko koristi kao keramički biomaterijal zbog svoje bioaktivnosti koju ispoljava kada se u vidu prevlake nanese na metalni implantat, kao i zbog kompatibilnosti sa sastavom ljudskih kostiju. Prevlake hidroksiapatitnog nano-praha elektroforetski su istaložene na peskiranu površinu uzoraka od nerđajućeg 316LVM čelika, pri konstantnom naponu i za različito vreme taloženja, a potom sinterovane u vakuumu na 1040°C i u atmosferi argona na 1000°C. Premda visoke temperature sinterovanja, koje su neophodne kako bi se dobile kompaktne prevlake velike gustine, mogu da dovedu do faznih promena kod hidroksiapatita, u ovom radu je pokazano da je na supsrtatu od 316LVM čelika moguće dobiti bioaktivne prevlake u kojima nije došlo do fazne promene zahvaljujući prirodi korišćenog hidroskiapatitnog nano-praha stehiometrijskog sastava. Visokotemperaturna stabilnost korišćenog HAp praha potvrđena je DTA-TG analizom u temperaturnom opsegu 23-1000°C, tj. na temperaturama na kojima su rađeni eksperimenti sinterovanja. Mikrostrukturna karakterizacija nanetih prevlaka urađena je korišćenjem SEM, dok je za određivanje faznog sastava korišćena XRD analiza., Hydroxyapatite is a widely used bioceramic material in implant coatings research because of its bioactive behavior when being deposited onto the metallic implant and compatibility with the human bones composition. The coating of nanosized hydroxyapatite was electrophoretically deposited on a blasted surface of stainless steel 316LVM samples at constant voltage, for different deposition times and subsequently sintered in both, vacuum and argon atmosphere, at 1040 and 1000°C, respectively. Although sintering temperatures needed to achieve highly dense coatings can cause HAp coating phase changes, the possibility to obtain a bioactive coating on 316LVM substrate, without the coatings phase changes due to the nature of the used stoichiometric nanostructured hydroxyapatite is presented in this work. The thermal stability of the used HAp powder was assessed by DTA-TG analyses over the temperature range of 23-1000°C, i.e., at the or nearby experimental sintering temperature. The microstructure characterization was accomplished using SEM, while phase composition was determined using XRD.

U radu ce biti prikazane mogućnosti primene plazma sprej postupka i elktroforetskog taloženja hidroksiapatitne prevlake na metalnu osnovu. U ortopedskoj hirurgiji implantati se najčešće izrađuju od legura titana ili nerđajućeg čelika na koje se nanosi hidroksiapatitna (HAp) prevlaka. Hemijski sastav sintetičkog hidroksiapatita je identičan onom koji čini mineralnu građu kostiju i zuba. Zato ga organizam prihvata kao biokompatibilan. Međutim, on nema zadovoljavajuću mehaničku čvrstoću da bi sam mogao da izdrži opterećenja u dužem vremenskom periodu. Njegovim nanosenjem na metalnu osnovu implantata dobijaju se dugotrajne i mehanički stabilne bescementne proteze., Hydroxyapatite coatings are being deposited on orthopedic implants metal surface to obtain biocompatibile cementless prostheses. There is chemical identity between synthetic hydroxyapatite and the one that makes teeth and bones mineral structure, so it can be easily accepted as biocompatibile by human organism. Disadvantage is the lack of long-term mechanical strength, what implies its application as a coating on an implant made of titanium alloy or stainless steel. There are several up to date technological methods for deposition these coatings on metallic implants, some of them are atmospheric plasma spray method. and electrophoretic deposition.

High strength low-alloyed (HSLA) Cr-Mn-Si steels belong to a group of steels that can reach their full mechanical properties after quenching and tempering. Those properties depend both on the temperature and time of tempering. Knowing the tempering parameters, it is possible to reach the desired properties of the treated steel. Some results on investigating the Hollomon-Jaffe equation (in parametric form) application for tempering of HSLA steel, are shown in this paper. The experiments were performed in real production conditions, using a standard material. The quenching was performed at 870°C, the heating period was always 30 min, with subsequent cooling into the oil bath. The tempering was carried out in temperature range from 480 to 680°C, while tempering time varied from 15 min to 24 h. The degree of tempering is referred through the hardness values changing. The experimental results have shown a pretty well agreement to tempering parameters, included in Hollomon-Jaffe equation, for this kind of HSLA steel.

This paper presents the investigation into the possibility for application of production process for casting aluminum alloys under the influence of electromagnetic field. The presented results were obtained from microstructure examination of Al alloy 2024 ingots casted with or without electromagnetic field. The microstructure characterization shows that under the influence of low-frequency (30-50 Hz) electromagnetic field it is possible to obtain finer and more homogeneous microstructure with reduced porosity. In the end, it is obvious in which way the operation parameters should be varied in order to get a good quality of ingots.

Proučavana je mikrostruktura odlivaka koji su dobijeni kontinuiranim livenjem Al legure EN AW 2024 čija se kristalizacija odvijala bez uticaja i pod uticajem elektromagnetnog polja malih frekvencija. Mikrostrukturna analiza pokazuje da se pod dejstvom niskofrekventnog elektromagnetnog polja dobija finija i po preseku homogenija mikrostruktura. S obzirom da su ovo kod nas prva primenjena istraživanja uticaja elektromagnetnog polja na proces očvršćavanja, rezultati jasno ukazuju u kom pravcu treba menjati radne parametre kako bi se dobili odlivci optimalnog kvaliteta., The results presented in this paper were obtained from microstructure examination of Al alloy 2024 ingots casted with or without low-frequency electromagnetic field. The microstructure characterization shows that it is possible to get finer and more homogeneous microstructure through the entire cross section of ingots casted with electromagnetic field, compared to ingots casted without electromagnetic field. Although, this is our first examination into the effect of electromagnetic field on process of solidification, it is obvious in which way the operation parameters should be varied in order to get a good quality of ingots.

U radu se navode osnovne karakteristike materijala i tehnologije toplog kovanje delova od Allegura. Za legure EN AW 2007 I EN AW 2024 ispitivana je mogućnost novog tehnološkog postupka livenja Al-legura pod dejstvom elektromagnetnog polja. Ovakav postupak omogućava modifikovanje mikrostrukture i poboljšanje mehaničkih osobinama odlivaka. Takođe, u radu se navodi i analiza kovanja u proizvodnim uslovima za leguru dobijenu istiskivanjem, uz pomoć odgovarajućeg SC.SuperForge softvera za 3D probleme. Kao primer, navode se rezultati distribucije ekvivalentnog napona u komadu koji se oblikuje u različitim fazama obrade., The paper presents the basic properties of materials and technology of hot forging of Al-alloy parts. For alloys EN AW 2007 and EN AW 2024 the possibility of new technological procedure for casting Al-alloys under the influence of electromagnetic field was investigated. Such a procedure enables modification of microstructure and improvement of mechanical properties of ingots. In addition to that, the paper presents analysis of forging in manufacturing conditions for alloy obtained by extrusion with the application of suitable SC.SuperForge software for 3D problems. The obtained results show the equivalent stress distribution in work-piece which is being formed.

The results presented in this paper were obtained from microstructure examination of Al alloy 2024 ingots casted with and without low-frequency electromagnetic field. The microstructure characterization shows that it is possible to obtain a finer and more homogeneous microstructure through the entire cross section of ingots casted with electromagnetic field, compared to ingots casted without electromagnetic field. Although, this is our first examination of the effect of electromagnetic field on the process of solidification, it is obvious in which way the operation parameters should be varied in order to get a good quality of ingots.

U cilju određivanja uticaja elektromagnetnog polja niske frekvencije prilikom kontinuiranog livenja aluminijumske legure 2024 izvršena je detaljna mehanička karakterizacija. Prikazani rezultati dobijeni su zateznim ispitivanjem na mernom sistemu Zwick/Roell Z 100 i predstavljaju deo opsežnog istraživanja. Uzorci za ispitivanje odliveni su pod različitim vrednostima radnih parametara: struje, frekvencije i jačine elektromagnetnog polja., In order to determine the effect of low-frequency electromagnetic field during the continual casting of 2024 Al alloy the detailed mechanical characterization was done. The presented results are obtained by tensile mechanical testing on testing machine Zwick/Roell Z 100 and they are the part of a voluminous research. The experimental samples are casted upon different values of operation parameters: current, frequency and intensity of electromagnetic field.

U ovom radu dati su osnovi tehnološkog postupka livenja ferosilicida za potrebe hemijske odnosno petrohemijske industrije. Prikazani su i rezultati ispitivanja uticaja brzine hlađenja na strukturu ferosilicijumske legure ultrazvučnom metodom., The fundamentals of technological procedure of casting FeSi-alloys for chemical industry are presented in this paper. The examination results of cooling rate influence on the high silicon cast iron obtained using ultrasonic testing are given.

Livačka industrija se, kao i većina ostalih industrija, bori za svoj opstanak. Opstanak joj omogućava tržište. U borbu za tržište livačka industrija ulazi sa novim tehnologijama, novim materijalima, produktivnošću i brigom za zaštitu životne sredine. Livačka industrija obojenih metala svoj prosperitet vidi u razvoju avioindustrije, autoindustrije i industrije transportne opreme., The metal casting industry, the same as the most industries, fights for its exist. In the struggle for the market position, the metal casting industry goes on gathering new technologies, new materials, better productivity and environment protection care. Non-ferrous metals foundry perceives own prosperity in aircraft, automotive and light transportation equipment industries development.

U radu su prikazani rezultati istraživanja stanja industrije proizvodnje i prerade legura železa u tečnom stanju u Srbiji u poslednjoj deceniji prošlog veka. Istraživanja su obuhvatila kapacitete livnica, tehnološke postupke livenja, stanje opreme, kadrove i uposlenost kapaciteta. Nakon analize prikupljenih podataka predloženi su strateški ciljevi razvoja za naredni period., The results of investigation on the situation in production and processing industry of iron alloys in liquid state in Serbia, in the last century latter decade, is presented in thi paper. The investigations encompassed the following: foundry capacities, foundry technologies used, the state of equipment, personnel and capacities employment. After collected data analysis, the strategic goals in development are suggested for the next period.

Kalaj je deficitaran i skup metal koji se u SR Jugoslaviji ne proizvodi. Zbog toga, preradi sekundarnih sirovina na bazi kalaj a treba pokloniti posebnu pažnju. Sirovinsku bazu za proizvodnju kalaja iz sekundarnih sirovina najvećim delom čine kalajne šljake, mulj i sunder, kao i međuprodukti u proizvodnji belih limova, otpadni beli lim, tehnološki ostatak i amortizovani hladnjaci iz automobilske industrije. U cilju valorizacije kalaja iz kalajne šljake, mulja i sundera urađena su laboratorijska i poluindustrijska ispitivanja redukcionog topljenja i rafinacije dobijenog sirovog kalaja. Na osnovu tih ispitivanja u ITNMS razrađene su metode i osvojene tehnologije za preradu ovih sirovina, koje su proverene proizvodnjom stotinak tona kalaja odnosno legura kalaja., Tin is scarce and expensive metal which is not produced in SR Yugoslavia Because of that, a special attention is paid on reprocessing tin-based secondary raw materials. Main resources of tin among secondary raw materials are mostly tin slags, sludges and sponges as well as by products from tin-plates production, residual tin-plates, processing tin scrap and amortized coolers from cars. In order to valuate tin from slags, sludges and sponges the comprehensive laboratory and semi-industrial investigations of reductional smelting and refining of obtained secondary tin are performed. Based on this investigations, the new methods and technologies for reprocessing of formerly mentioned secondary raw materials are developed and tested through production of some hundred tones of tin and tin alloys.