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Silica sand is an important non-metallic mineral raw material within the resources of the Republic of Croatia. Croatian silica sand reserves could meet industrial needs over the long term. The 15 exploitation fields are registered, and the average annual production in the last 10 years is about 240, 000 tonnes. Depending on quality i.e. specific physical and chemical properties (grain size distribution, chemical and mineral composition, moisture content, etc.), silica sand is used as the basic mineral raw material for many industrial applications. To meet defined chemical and physical specifications according to intended application, the raw sand often has to be subjected to extensive physical and chemical processing. The paper describes main beneficiation methods used in the processing of sand intended for industrial uses. Beneficiation procedure applied at the silica sand deposit "Jerovec" located in north-western Croatia is presented, as well as the results achieved under field conditions.

Glass recycling is the process of turning waste glass into usable products. Glass is an ideal material for recycling and in some cases can be used repeatedly without any deterioration in its physical properties. There are several types of glass entering the waste stream each with different chemical compositions and physical properties. Recycling of complex material such as a glass is a simple but hugely beneficial process which consists of several steps. The complete recycling loop can be repeated an infinite number of times and the quality of the glass will never deteriorate. The paper describes recycling cycle, recycling technology and overview of glass recycling state in EU.

U separacijama tehničko-građevnog kamena u kojima se za proizvodnju standardnih klasa kamena koristi „ mokri“ postupak oplemenjivanja, dolazi do stvaranja značajnih količina otpadne vode. Otpadna voda onečišćena je sitnim česticama jalovine, te česticama sirovine koja se prerađuje. Mokri postupak najčešće se primjenjuje u slučaju pojave primjesa gline ili/i zemlje koje se izdvajaju pranjem na sitima. Koncentracija čvrste faze u otpadnoj vodi ponekad može iznositi i više od 100 g/l suspenzije, a najčešće se radi o vrlo sitnim česticama čija veličina uglavnom ne prelazi 100  m, što će pak ovisiti o količini jalovine, te fizičko-mehaničkim značajkama i jalovine i kamena. Pročišćavanje takve vode otežano je zbog velikog sadržaja vrlo sitnih čestica. Postupci pročišćavanja uglavnom se svode na sedimentaciju i filtraciju, jer kamen ne podnosi visoke proizvodne troškove.

U tehnologiji prerade mineralnih sirovina vrlo često se susrećemo s velikim količinama otpadnih voda koje osim kemijskog onečišćenja sadrže i mehaničke nečistoće, najčešće fine čestice mineralnog porijekla. Ispuštanje takvih voda u pojedine dijelove okoliša - rijeke, mora i jezera danas uglavnom nije dopušteno. Sve stroži propisi zaštite okoliša prisiljavaju nas da otpadne vode pročistimo do prihvatljive razine (vraćanje u proces, ispuštanje u recipijent), a zaostale muljeve propisno zbrinemo. U radu će se opisati postupci pročišćavanja otpadnih voda iz separacija tehničkog kamena i pogona za preradu arhitektonsko-građevnog kamena.

Paper is concerning floatability of coal slurries by means of different flotation collectors. The goal of the work was verification of floatability of coal slurries as well as flotation collectors selectivity. The investigation was carried out in a column flotation.

Rad opisuje održani Forum u cilju upozvananja studenata s različitim aspektima rudarstva i disciplinama vezanim uz rudarstvo u cilju popularizacije struke.

Učinkovitost recikliranja, tj. postignuto iskorištenje otpadnog materijala (otpada) i kvaliteta dobivenih produkata, a time i cijena (recikliranja) značajno ovise o složenosti otpada. Što je otpad složeniji, potrebna je primjena sofisticiranije a time i skuplje tehnologije i opreme za recikliranje. Proces recikliranja krutog otpada u velikoj mjeri obuhvaća postupke koji se tradicionalno koriste u oplemenjivanju mineralnih sirovina. Sitnjenje, klasiranje i sortiranje čine osnovu svakog i malo složenijeg procesa recikliranja. Bez njihove primjene nije moguće učinkovito separirati pojedine sastavne materijale otpada predviđenog za recikliranje. Učinkovitost separacije prikazuje se pomoću dva osnovna pokazatelja - iskorištenja korisne komponente i čistoće koncentrata.

Kvarcni pijesci zauzimaju značajno mjesto u resursnom potencijalu RH. Hrvatska raspolaže relativno velikim rezervama kvarcnog pijeska koje mogu na duži rok zadovoljiti potrebe industrije, a poznate su brojne pojave i nalazišta na području Istre, Slavonije, Hrvatskog Zagorja, Dalmacije, Like, Korduna, Banije, Podravine i Posavine. Registrirano je 16 eksploatacijskih polja, površine 25, 34 km2, a prosječna proizvodnja kvarcnog pijeska u posljednjih desetak godina iznosi oko 240.000 t/god. Ovisno o kvaliteti, koja podrazumijeva određene fizičko-kemijske značajke (granulometrijski, kemijski i mineraloški sastav, sadržaj vlage i dr.), kvarcni pijesak se koristi u različite industrijske svrhe: kao osnovna sirovina za proizvodnju stakla, za izradu kalupa i jezgri u ljevarskoj industriji, kao abrazivni materijal, u kemijskoj i keramičkoj industriji, industriji građevnog materijala i dr. Najstrože zahtjeve za kvalitetom pijeska kao osnovnom sirovinom postavljaju proizvođači stakla koji, ovisno o vrsti stakla, traže što viši udio SiO2 ( 95%) i što niže udjele nepoželjnih primjesa koje u staklu izazivaju obojenja i mrlje ( 0, 5% Fe2O3,  0, 3% TiO2 i dr.). Rovni pijesak obično ne ispunjava te zahtjeve, te je neophodno njegovo oplemenjivanje kako bi se dobila kvarcna sirovina odgovarajuće kvalitete. Zbog svog mineralnog sastava i načina sraslosti pojedinih minerala proces oplemenjivanja kvarcnog pijeska može biti vrlo složen i često uključuje primjenu čitavog niza fizikalnih i fizikalno-kemijskih postupaka. U radu su opisani osnovni separacijski postupci koji se koriste u procesu oplemenjivanja kvarcnog pijeska namijenjenog za staklarsku industriju. Dan je prikaz tehnološkog procesa oplemenjivanja koji se primjenjuje na separaciji poduzeća IGM "Pješčara Jerovec" kraj Lepoglave s ciljem postizanja kvalitete pijeska neophodne za proizvodnju ambalažnog stakla. Također su prikazani rezultati koji se postižu oplemenjivanjem u pogonskim uvjetima.

The crushing of the mineral raw material is the most essential mechanical operation within mineral processing. It is also an inefficient, energy intensive process that consumes billions of kilowatt-hours (kWh) per year. In fact only 1% of the total energy input into size reduction processes is used in individual particles breaking and changing of solid material dispersion state. Since the technology is well known, improvements in comminution are dependent upon optimizing the application and operation of that technology. In addition, the design of aggregate crushing plants requires expensive equipment, and missteps in design are difficult and expensive to correct. Unfortunately this often lend to the subjective judgment of an individual, resulting in the conservative over-design of crushing plant equipment. These facts resulted that we tried to find out, on the basis of extensive literature review, which rock mechanical properties are of crucial importance on prediction of jaw crusher performance and to develop large scale laboratory testing system of rock properties that can be significantly correlated with jaw crusher performance.

Paper is concerning floatability of black coal from Mine Lazy by means of Flotalex, Montanol and PE2 collectors. The goal of the work was verification of floatability of mentioned coal as well as flotation collectors selectivity. The investigation was carried out on class – 0, 5 mm in a column flotation. From the flotation results followed that Flotalex and Montanol have approximately equal recovery while Flotalex have better selectivity. Results which were obtained by PE2 collector are not satisfactory.

Mining activity in the Republic of Croatia is based mainly on the exploitation and production of non-metallic mineral raw materials. Since carbonate rocks are predominant in the geological structure of Croatia, in the majority of quarries limestone and dolomite are exploited. Dolomite is widely used in various industries e.g. construction industry, building material industry, metallurgy, glass industry, etc. In glassmaking it is added to raw material mixture in the form of dolomite grits (- 1 mm) as one of the essential components for the input of glass modifiers that is CaO and MgO. To be used for this purpose, dolomite has to meet certain standard specifications established by the glass industry. In most cases, dolomite exploited in quarries does not satisfy demanding specifications and, therefore, its further processing is needed. The paper describes processing technology for dolomite intended for use as a raw material in container glass production. Fe2O3 content in exploited dolomite before beneficiation varies in range from 0.052% to 0.07%. By beneficiation procedure applying dry magnetic separation, dolomite grits with Fe2O3 content less than 0.05%, which meets the requirements of container glass industry, are obtained. The results presented in this paper are achieved under field conditions.

Geotermalno polje Zagreb sastoji se od tri lokaliteta koji su definirani u Glavnom rudarskom projektu (Projekt je u skladu s odredbom iz čl. 41 stavka 1. Zakona o rudarstvu NN br. 35/95, Klasa:UP/I-310-07/95-03/45, ur. Br. 526-04-96-04 od 26. rujna 1996. god.) i Elaboratu o rezervama geotermalne vode (Rješenje Ministarstva gospodarstva rada i poduzetništva: Klasa:UP/I-310-01/03-03/228, ur. Br. 526-04-04-04 od 13. siječnja 2004. god.). Na GPZ izrađeno je ukupno 14 bušotina, a probna proizvodnja započela je 1981. bušotinom Mla-1. Glavnim rudarskim projektom i Elaboratom o rezervama na GPZ predviđeno je crpljenje, iskorištavanje i utiskivanje geotermalne vode u zatvorenom cirkulacijskom sustavu.

The non-metals and building materials industry accounted for approximately 8 % of the total industrial output in Croatia during year 2004. Nowadays more than 200 trading companies in Croatia deal with the exploitation of solid mineral raw materials, and almost 50 % of them exploit technical stone. In the majority of technical stone quarries, the deposits of carbonate rocks (limestone and dolomite) are exploited, whereas in only eight quarries the eruptive rocks are exploited. If raw material contain impurities, which necessitates wet processing operation, waste water must be cleaned before being let out of the processing plant or returned to the dressing process. In the paper the waste water treatment in technical stone quarry is presented.

The demand for secondary materials, primarly steel, glass and plastics, has led to the significant development and application of new techniques, equipments and plants used in recycling. The paper describes the basic techniques for solid waste comminution and presents the typical machines and equipment used for this purpose. The aim of the paper is to draw domestic industry's and contractor's attention to the production area which in spite of certain production potentials still doesn't exist in Croatia.

The Croatian non-metals industry comprises exploration, exploitation and processing of non-metallic mineral raw materials. By beneficiation of these rock standard stone sizes for the production of concrete, asphalt masses, of supporting layers in road works and railroad ballast were obtained. In most technical stone quarries, rock deposits of a carbonaceous structure are exploited, whereas just some few quarries are exploiting rock deposits of a siliceous structure. An overview of eruptive technical stone production in the Republic of Croatia is given in this paper. The technology of stone exploitation and dressing are shown on quarry Jelenje Vode.

The paper presents the results of attrition cleaning obtained by testing the samples of quartz sand under laboratory conditions. The tests were carried out in two types of laboratory attrition cell – with circular and octagonal cross section, at different values of operating parameters which are supposed to have the main influence upon the attrition efficiency: suspension density, attrition time and stirrer speed. In each type of attrition cell two series of tests were conducted on two quartz sand samples with different SiO2 i.e. impurity contents. Indicators of attrition efficiency were the content of the particles – 0.063 mm and content of main impurities (Al2O3, Fe2O3) removed through the attrition process. By comparing the results of both series of tests conducted in mentioned types of attrition cells, information on dependence of attrition efficiency on feed material composition, operating parameters and attrition cell construction were obtained.

The soil washing process is similar to one applied in mineral processing. In mineral processing the useful mineral component is separated from tailings, and in soil washing relatively small amount of highly contaminated concentrate is separated from the mass of cleaned soil. The washing process includes several stages: soil preparation (pre-screaning and possibly crushing), liberation and separation of individual components respectively, classification, sorting and dewatering. The paper describes the individual stages of washing as well as the most important machines which is used in the process. Personal expirience wtih the application of attrition and column flotation are mentioned.

Flotation is universal method to fine coal processing. Selectivity and efficiency of flotation depends not only on surface characteristics of particles, but also on hydrodynamic condition in flotation cell. The goal of the research was to compare flotation column and conventional mechanical flotation cell in coal flotation. The tests was carried out in both flotation cells in the same conditions. The results indicated that the mechanical cell has greater recovery, whereas the flotation column has a considerably better selectivity since it provides a concentrate of better quality.

The quality of quartz sand can be improved by reducing the oxide coatings on the quartz grains. In this direction, a study has been made to consider the possibility of coatings removal from quartz sand by attrition cleaning. Tests were conducted in a laboratory attrition cell at different values of operating parameters: suspension density, attrition time and stirrer speed. Indicators of attrition efficiency were the content of the particles – 0, 063 mm and content of main impurities (Al2O3, Fe2O3) removed through attrition process.

Oplemenjivanje sitnog ugljena oduvijek je bilo složenije od krupnog, a tako je ostalo i do danas. Učinkovitost oplemenjivačkih uređaja koji se koriste u obogaćivanju ugljena smanjuje se sa smanjenjem prerađivane veličine zrna. Da bi došlo do odvajanja korisne od nekorisne komponente mineralne sirovine, u flotaciji se koriste razlike u površinskim značajkama minerala. Selektivnost procesa flotacije također ovisi o kemijskim i fizikalnim varijablama, odnosno o hidrodinamičkim uvjetima u flotacijskoj ćeliji. Cilj rada bio je provesti istraživanja čiji rezultati će pružiti spoznaje o mogućnosti primjene flotacijske kolone za oplemenjivanje sitnog ugljena, odrediti utjecaj pojedinih procesnih varijabli na flotabilnost, ustanoviti optimalne uvjete i režim flotiranja, te usporediti flotacijsku kolonu sa konvencionalnom mehaničkom flotacijskom ćelijom. Istraživanja su najvećim dijelom provedena flotiranjem kamenog ugljena klase – 0, 5 mm u flotacijskoj koloni. Utjecaj vrste i količine kolektora ispitan je testiranjem uz dodatak kolektora različitih proizvođača u različitim dozama. Provedene analize potvrdile su značajan utjecaj vrste kolektora na iskorištenje mase koncentrata i na sadržaj pepela u koncentratu. Doza kolektora ima veći utjecaj na sadržaj pepela u koncentratu, a manji na iskorištenje. Najbolju selektivnost od tri testirana kolektora pokazao je Flotalex, pa je korišten u svim daljnjim pokusima. Optimalna doza kolektora određena je na temelju zasebne serije testova, a optimalno vrijeme flotiranja utvrđeno je temeljem pokusa frakcijske flotacije. Na temelju petrografskih analiza koncentrata frakcijske flotacije došlo se do zaključka da grupa macerala vitrinita posjeduje najbolju flotabilnost, grupa inertinita manju, a najmanju grupa liptinita. Plan testiranja utjecaja protoka zraka, gustoće pulpe, veličine zrna, kao i njihovog međudjelovanja sastavljen je statističkim metodama prema Central Composite Design-u u programskom sustavu Statistica for Windows 4.5. Na temelju dobivenih rezultata može se zaključiti da je količina zraka jedina od testiranih fizikalnih varijabli koja je pokazala vrlo velik utjecaj na iskorištenje mase koncentrata i na sadržaj pepela u koncentratu. Dobiveni rezultati ukazuju da s povećanjem protoka zraka raste iskorištenje, ali istovremeno i sadržaj pepela, odnosno da se smanjuje sadržaj pepela u koncentratu. Analizom utjecaja veličine zrna pokazalo se da je s obzirom na sadržaj pepela u koncentratu to druga varijabla prema utjecajnosti, dok sa aspekta iskorištenja zauzima treće mjesto. Gustoća pulpe treća je varijabla prema utjecajnosti s obzirom na udio pepela u koncentratu, ali i najutjecajnija s obzirom na iskorištenje mase koncentrata. Kada se usporedi međudjelovanje pojedinih varijabli, tada najveći utjecaj na sadržaj pepela u koncentratu ima interakcija gustoće pulpe i veličine zrna, zatim veličine zrna i protoka zraka, a najmanje međudjelovanje protoka zraka i gustoće pulpe. Sa aspekta iskorištenja, najveći utjecaj ima međudjelovanje gustoće pulpe i veličine zrna, zatim gustoće pulpe i protoka zraka, a najmanji utjecaj ima interakcija protoka zraka i veličine zrna. Serija testova u mehaničkoj flotacijskoj ćeliji u uvjetima jednakim kao i u koloni pokazala je da mehanička ćelija postiže više iskorištenje, dok flotacijska kolona posjeduje znatno bolju selektivnost jer daje kvalitetniji koncentrat. Test flotacije sa čišćenjem koncentrata pokazao je da primjena mehaničke ćelije u grubom stupnju i kolone za čišćenje koncentrata dodatno poboljšava iskorištenje.

Članek pojednava o flotovalentnosti černeho uhli z Dolu Lazy pomoci sberaču Flotalex, Montanol a PE2. Cilem prace bylo overeni flotovalentnosti uhli, stejne jako posouzeni selektivity flotačnich sberaču, ktere byly použity. Testy byly uskutečneny na zrnitostni tride - 0, 5 mm pomoci kolonove flotace. Z vysledku flotace vyplynulo. že Flotalex a Montanol maji približne stejny vynos i kdiž Flotalex pusobi selektivneji. Vysledky ktere byly ziskany se sberačem PE2 nejsou priliš uspokojive.

The greatest part of crushed stone, gravel and sand production is won by open pit operations, whereas gravel and sand partially also from river beds. Its obvious that such a mining activity provoke some changes in the configuration and environmental characteristics of the region, in the temporary or permament disapperance of vegetable or animal species and in the creation of noise, dust and waste water. However, mentioned mining operations shouldn't have only negative effects on the landscape and land potential, but they can discover and predetermine potential of exploited area for various communal purposes after exploitation (eg. sports and recreation centers, campsites, resorts, fish-farms, etc.). In this paper, construction aggregates production in plants located in the vicinity of Zagreb, the capital of Croatia are presented. Advantages and disadvantages of aggregates production in the urban area in the spirit of sustainable development are discused.

Paper is concerning floatability of black coal from Mine Lazy by means of Flotalex, Montanol and PE2 collectors. The goal of the work was verification of floatability of mentioned coal as well as flotation collectors selectivity. The investigation was carried out on class &#8211 ; ; 0, 5 mm in a column flotation. From the flotation results followed that Flotalex and Montanol have approximately equal recovery while Flotalex have better selectivity. Results which were obtained by PE2 collector are not satisfactory.

Na tržištu tehničkog kamena najtraženije su klase veličine zrna 4/8, 2/4, -4, -2 mm, čiji maseni udio prevladava u agregatima za izradu betona i asfalta. Međutim, proizvodnja tih klasa nije uvijek jednostavna. Pored zahtjeva za količinom, redovito se traži određeni grano-sastav i oblik zrna kamenog agregata, te minimalan udio čestica veličine &#8211 ; 0, 09 mm. Do prije desetak godina, najčešće su za proizvodnju navedenih klasa korištene udarne drobilice i čekićare, dok se danas u tu svrhu sve češće koriste vertikalne udarne drobilice. Vertikalne udarne drobilice predstavljaju izvjestan tehnološki napredak koji se prvenstveno očituje u većem udjelu zrna kubičnog oblika u izlaznom materijalu i manjem habanju udarnih elemenata i obloge u odnosu na prije spomenute drobilice. U članku su opisane osnovne konstrukcijske značajke i princip rada vertikalnih udarnih drobilica, te je analizirana njihova učinkovitost (grano-sastav proizvoda, udio zrna povoljnog oblika, udio čestica &#8211 ; 0, 09 mm) u ovisnosti o utjecaju pojedinih tehnoloških parametara.

The production of nonmetallics in Croatia highly exceeds the production of any other mineral raw material. Zagreb, capital of Croatia, is the biggest consumer of sand, gravel and crushed rock aggregates. Since listed materials, due to their low cost, don’t bear long transport, nearby Zagreb numerous quarries and gravel-pits were opened. An overview of sand and gravel production in Croatia is given in this paper. The technology of gravel extraction and dressing are shown on the example of Novo Čiče gravel-pit, together with geological structure of surrounding area and the properties of extracted gravel.

The paper reports on safety at work measures that are carried out at execution of mining operations in technical stone quarries. Since the technological process of stone exploitation consists of several phases, not only safety at work measures, but also specific protective measures for each individual phase are described. During stone exploitation and processing it always comes to dust and waste gases emission, which in some situations can impair the quality of air and environment. Therefore, special attention is paid to sources of dust emission and methods of polluted air purification for certain machines, vehicles, devices and work operation. A processing plant with marked places of dust removal is shown, and work of cyclone colectors and fabric filters is described.

Nowadays, the preservation and improvement of the quality of water, air and soil in the complete system of environmental protection is attended with great care. The most frequent objections in the use of fossil fuels in power plants are directed towards the emission of harmful matters, especially if the thermoenergetic plants are situated in the immeditate neighbourhood or within urban areas. In this paper a review of material particle emissions and emissions of SO2, NOX, CO2, from units of the Croatian Energetic System fed by mazout, gas, and coal has been given. As example, the production flowsheet of the Zagreb Power and Heating Plant (ZPHP) has been investigated, the emission points, from the moment of fuel receptance up to its burning in the boiler, i.e. to the atmospheric gas exhaust, have been identified. Law regulations, control system and the present protecting measures have been described and suitable improvement suggestions proposed.

The main part of the needed metal in the Republic of Croatia is secured by collecting and recycling of metallic scrap, and a part is imported. By collecting and recycling in the year 1998 altogether 113.828 t of various metallic waste has been produced. The iron and steel scrap, which composes 90 % of the whole material, is renovated in two steel plants which in the year 1998 produced 104.114 t of raw steel. With the aim to collect a maximum of metallic scrap a waste stock market has been organized, and 1995 a recycling plant also has been erected. In the paper figures about the import and export of metals in Croatia are given, the technology of the recycling process is reviewed together with the basic figures, and the environmental protection measures in the plant are represented.

The production of technical stone, gravel and sand for the building industry is a very important part of the mining production regarding volume and the financial value as well. The most demanded classes are with grain sizes &#8211 ; 4 and &#8211 ; 2 mm but their production is not always simple. In addition to volume, the specific grain size composition, grain shape and minimal portion of the particles &#8211 ; 0, 09 mm (filler) usually are demanded. Until about ten years ago the portion of the impact and hammer crushers, less often cone crushers were used in the production of these classes. Nowadays the vertical impact crushers (rotor mills) are mainly applied for this purpose. In the paper are presented some of these crushers used in the quarries and gravel-pits in Croatia. Their efficiency (capacity, grain size composition, grain shape, filler portion) depending on the influence of the some technological parameters, as for example grain composition of the feed material, physical-mechanical rock properties, moisture content and etc. are analysed.

Sitnjenje je proces u kojem pod djelovanjem mehaničkih sila mijenjamo disperzno stanje čvrstih tvari. Disperzno stanje jednoznačno je određeno granulometrijskim sastavom. Do sitnjenja dolazi usljed deformacije zrna pri čemu deformacija ovisi o načinu nanošenja sile, njezinoj brzini i veličini. Drobljenje pojedinačnog zrna najučinkovitija je metoda sitnjenja, jer su gubici energije usljed trenja i neproduktivnog naprezanja u trenutku drobljenja izbjegnuti. Najveći gubici energije su u mlinovima s kuglama i to uslijed trenja između novostvorenih zrna i tih zrna s kuglama i oblogom mlina. Nove spoznaje dovele su do boljeg razumjevanja sitnjenja u realnim uvjetima, te inovacijskih zahvata s kojima je povećana učinkovitost pojedinih uređaja i to, kako u pogledu grano-satava i raščina zrna tako i u pogledu utroška energije. Konstruirano je nekoliko novih drobilica od kojih se u praksi najčešće spominju visokotlačlna drobilica s valjcima i inercijske konusne drobilice.

Stručna ekskurzija studenata RGN fakulteta u Zagrebu u Velenjski rudnik lignita.

Šljunak iz korita rijeke Save sadrži čestice ugljena koje nakon klasiranja ostaju u pijesku. Sadržaj ugljena u klasi -2 mm kreće se od 0,5 do 2,5 %, u klasi –4 mm do 3 %, dok ga u relativno uskim klasama kao npr. 2/1 odnosno 1/0,5 mm ima i do 6 %. U radu je prikazano istraživanje mogućnosti oplemenjivanja šljunka iz korita rijeke Save pomoću metoda gravitacijske koncentracije. Cilj istraživanja bio je ustanoviti sadržaj ugljena u šljunku i pijesku, te ispitati mogu li se iz pijeska izdvojiti čestice ugljena i u kojoj mjeri. Sadržaj ugljena u uzorcima ispitivan je pliva-tone analizom, a izdvajanje ugljena iz pijeska na tri uređaja: plakalici, spirali i koncentracijskom stolu. Tijekom ispitivanja testirano je više klasa sa različitim sadržajem ugljena. Najbolji rezultati u pogledu kakvoće koncentrata dobiveni su radom na plakalici, dok su najveća iskorištenja pijeska u koncentratu postignuta na spirali.

In the paper the results of an investigation of the separability of a slag from an electric furnace are given. The investigation was carried out in a Humbolt-Wedag dry high-intensity magnetic separator and a Davis wet low-intensity magnetic separator. The following size ranges were examined: -2; 2/1; 1/0,5; 0,5/0,25 mm.

The investigation of possibilities of electric slag beneficiation was carried out in two phases. In the first phase magnetic methods were applied, during which dry high-intensity and wet low-intensity magnetic separators were used. In the second phase gravity concentration methods were applied, with treatment on concentrating tables. The iron content in the slag was established by atomic absorbtion spectrophotometry.

U radu su prikazani izvori emisija prašine na kamenolomima tehničkog kamena, te načini pročišćavanja onečišćenog zraka za pojedine strojeve, vozila, uređaje i radne operacije. Dat je prikaz postrojenja za oplemenjivanje s označenim mjestima otprašivanja, te opis rada aerociklona i tkaninskog filtra.

Municipal solid waste is a specific kind of waste due to its market inhomogenity and small marketing value of the constituents. Therefore, such a waste is deposited or burned, sometimes separated before or after incineration. Using front-end separation systems the energetic value of the waste increases and the amount of ash, slag and reject gases decreases, so the total mass of waste to be discarded can significantly be reduced. The separation process includes a rather extensive amount of operations – crushing, sizing, and sorting being the most important. In the paper the devices used in the mentioned operations are described, sorting result are quoted, and flowsheets for three variants of separation processes are given, with the basic indicators of their efficacity.

The gravel in the Sava-river bed contains coal particles that after classifying remain in the sand and so make it practically imposible to use it in construction works. The coal quantity varies: in the size class - 4 mm it fluctuates from 0.5 to 2 %, in the relatively narrow classes, e.g. 2/1 mm or 1/0.5 mm, there it raises up to 6 %. The possibilities of separation of the sand and coal, e.g. sand cleaning, was tested by standard gravity concentration equipment: jigs, spirals and concentration tables. The following size classes were treated: 4/1, 2/1, 4/0.5, -1, 1/0.5 and -0.5 mm, with coal shares of 1, 3 and 6 %. The best results gave the jigging tests and the highest recovery values for the sand were obtain by the Humphreys spiral.

Temeljna zadaća spaljivanja otpada je smanjenje volumena, a time i prostora potrebnog za odlaganje. Spaljivanje ponekad doprinosi i smanjenju troškova odlaganja nekih vrsta tehnološkog otpada, a koristi se i kao dodatni izvor energije obično u kombinaciji s nekim fosilnim gorivom. Pored izgaranja u spalionicama, otpad se može spaljivati i u pećima za proizvodnju cementnog klinkera, a u novije vrijeme i u postrojenjima za katalitičko izgaranje, te u postrojenjima za biokonverziju gdje se prije izgaranja pretvara u metan. Tijekom izgaranja stvaraju se čvrste, plinovite i tekuće otpadne tvari, koje najvećim dijelom napuštaju prostor izgaranja nošene dimnim plinovima. Prije ispuštanja plinova u atmosferu, ove nečistoće izdvajaju se u uređajima za čišćenje dimnih plinova. U radu su prikazani uređaji koji se obično koriste za čišćenje otpadnih plinova, njihove tehnološke značajke, učinkovitost, te mogućnost primjene.

Mineralne sirovine su za čovjeka vrlo značajne, kako gospodarski, tako i ekološki.U prošlosti se mislilo da su mineralne sirovine poklonjene, odnosno "besplatne".Danas znamo da plaćamo visoku cijenu takvog odnosa prema prirodi, stoga smo svjedoci sve većeg broja i sve veće strogoće zakonske regulative, koja uvjetuje eksploataciju mineralnih sirovina.Pored zahtjeva za racionalno gospodarenje mineralnim sirovinama, sama eksploatacija uuvjetovana je potrbom svrhovite zaštite okoliša.Postavlja se pitanje znače li ekološke norme i neizbježan porast troškova eksploatacije ili mogu postati poticaj da ona u sebi pronađe skrivene mogućnosti, čime će povećati produktivnost i iskorištenje prirodnih resursa.Primjer eksploatacije i oplemenjivanja tehničko-građevnog kamena dolomita u ležištu "Veličanka", prikazuje potrebnu zaokruženost korištenja mineralne sirovine, a samim tim i dostatno smanjenje možebitnih nepovoljnih utjecaja na okloiš.

Reciklaža je tehnološki proces kojim se iz otpada odvajaju korisne komponenta da bi se povećala tržišna vrijednost.Komunalni otpad je posebna vrsta otpada i to zbog izrazite nehomogenosti sastava i male tržišne vrijednosti komponenti.Zbog toga ovaj se otpad deponira ili spaljuje, ponekad prethodno reciklira i to obično prije spaljivanja.Reciklažom se povećava toplotna vrijednost otpada, smanjuje količina pepela, troske i otpadnih plinova, a manja je i ukupna masa otpada koji treba deponirati.Proces reciklaže obuhvaća cijeli niz operacija od kojih su najvažnije sitnjenje, klasiranje i sortiranje. U radu su prikazani aparati koji se koriste u spomenutim operacijama, navode rezultati sortiranja, te daje shematski prikaz triju varijanti procesa reciklaže uz navođenje osnovnih pokazatelja njihove djelotvornosti.

The article discusses flotoflocculation of black coal in flotation column.

Sve kraći uporabni vijek elektroničkih uređaja i opreme posljedica je sve bržeg razvoja i usvajanja novih tehnologija, te uzrok eksponencijalnog rasta količina električnog i elektroničkog otpada, kako na globalnoj razini, tako i u RH, a isti trendovi mogu se očekivati i u budućnosti. Recikliranje kao integralni dio suvremenog sustava gospodarenja otpadom omogućava dobivanje sekundarnih sirovina, čime se smanjuje količina otpada i prostor potreban za njegovo odlaganje, štede se primarne sirovine i smanjuju emisije u okoliš pri proizvodnji novih proizvoda, itd. Osnovni cilj kojem se teži u recikliranju je separirati različite materijale sadržane u otpadu u zasebne produkte koji se mogu upotrijebiti kao sekundarna sirovina i koji kao takvi imaju određenu tržišnu vrijednost. Preduvjet uspješne separacije je postizanje raščina, tj. oslobađanje međusobno (mehanički, kemijski ili termički) spojenih različitih materijala. Uspjeh recikliranja električnog i elektroničkog otpada ovisi o značajkama otpada, separacijskih postupaka i uređaja koji se pri tome primjenjuju, te naravno uvjetima (vrijednosti radnih varijabli uređaja) u kojima se separacija izvodi. Prva faza procesa recikliranja sastoji se od ručne demontaže i izdvajanja krupnijih dijelova otpadnih uređaja, pri čemu se izdvaja veći udio željeza, bakra, stakla i plastike. Ostale dijelove potrebno je usitniti zbog postizanja raščina, a zatim prikladnim separacijskim postupcima izdvajati pojedine vrste materijala. U ovom radu su iz televizijskih aparata ručnom demontažom izdvojeni uz kučište i veliki kondenzatori i katodne cijevi koje sadrže fosforni prah i kadmij, te su zbog nemogućnosti sigurnog ispitivanja isključene iz daljnjeg ispitivanja. Izdvojena drvena kučišta isključena su iz daljnjeg ispitivanja jer je s vremenom došlo do kontaminacije štetnim tvarima kao što su krom, olovo, živa, sumpor, nikal, cink i sl., a u plastična kučišta umiješani su bromirani inhibitori gorenja koji, i u vrlo malim količinama, kontaminiraju plastiku čineći je nepogodnom za dobivanje nove plastike. Ostali materijal je, s obzirom na svoje značajke, podijeljen u tri grupe koje su ispitivane zasebno. Grupa nazvana „Zvučnici“ sastavni je dio audio sustava, a sadrži najviše željeza i nešto manje bakra u svitcima, uz plastiku, karton i tekstil. Grupa „Otklonski svitci, kabeli, konektori i žice“ ima veliku zastupljenost bakra, a treća grupa „Tiskane pločice“ uz vodljivu bakrenu strukturu sadržava i mnoštvo rijetkih metala na nevodljivoj osnovi (vitroplast, pertinks). Za svaku od prethodno navedenih grupa sastavljen je zaseban plan istraživanja. Za sve grupe prvo je provedeno sitnjenje u cilju postizanja raščina, zatim sijanje za dobivanje klasa pogodnih za testove u pojedinim separatorima. Plan testiranja separacije u zračnoj struji i elektrostatičke separacije sastavljen je uz upotrebu statističkog planiranja eksperimenata u programskom sustavu Statistica (Version 8, tvrtke StatSoft) prema centralno složenom dizajnu (Central Composite Design) koji uključuje 17 pokusa za svaku klasu na pojedinom uređaju. Analizom varijance utvrđen je utjecaj pojedine nezavisne varijable odnosno utjecaj međudjelovanja po dvije (od tri testirane) nezavisne varijable na jednu od dvije zavisne varijabli (kvaliteta koncentrata ili maseno iskorištenje) uz procjenu veličine tog utjecaja. Utjecaj pojedinih varijabli u gravitacijskoj i magnetskoj separaciji testiran je na način da je mijenjana vrijednost jedne varijable, dok su sve ostale držane konstantnim. Testovi separacije u zračnoj struji pokazali su da na kvalitetu koncentrata najveći utjecaj ima visina pregrade, a najmanji brzina zračne struje, a od međudjelovanja varijabli najviše utječe visina pregrade i položaj ulaznog otvora. Visina pregrade u svim slučajevima imala je najveći utjecaj na iskorištenje. Najbolji rezultati (kvaliteta koncentrata od 99 % do 100 % uz iskorištenja od 80 % do 99 %) postizani su separacijom zrna većih od 2 mm (klase 4/2 mm i 3,15/2 mm), a sa smanjenjem veličine zrna smanjivala se i efikasnost separacije. Elektrostatičkom separacijom postizala se visoka kvaliteta koncentrata u svim klasama, a najbolji rezultati dobiveni su u testovima s najkrupnijom klasom (4/2 mm). U svim testovima najveći utjecaj imao je položaj separacijskog noža. Kada se razmotre međudjelovanja varijabli, najveći utjecaj imalo je međudjelovanje položaja separacijskog noža s naponom ionizacijske elektrode i s brzinom okretanja bubnja. Rezultati dobiveni magnetskom separacijom pokazali su da je u najvećem broju slučajeva (pogotovo za krupnije klase) mokra separacija bolja od suhe, dok su se razlike smanjivale sa smanjenjem veličine zrna. Najbolji rezultati i mokre niskointenzivne i suhe visokointenzivne magnetske separacije postignuti su s najsitnijom klasom, -0,5 mm. Testovi gravitacijske koncentracije pokazali su da je za kvalitetniji koncentrat potrebno raditi s manjim nagibima ploče koncentracijskog stola. Temeljem dobivenih rezultata predložena je segregacijska shema recikliranja elektroničkog otpada. Osnovna hipoteza ovog rada, da se uređaji i postupci koji se koriste u oplemenjivanju mineralnih sirovina mogu koristiti i za recikliranje električnog i elektroničkog otpada potvrđena je temeljem rezultata provedenih ispitivanja., The ever shorter life cycle of electronic devices and equipment is a consequence of increasingly quick development and adoption of new technologies, and a reason for exponential growth of the quantity of electrical and electronic waste, both at the global level and in the Republic of Croatia, and identical trends can be anticipated also in the future. Recycling as an integral part of the contemporary waste management system enables obtaining of secondary raw materials, whereby the quantity of waste and the space necessary for its disposal are reduced, primary raw materials are saved and environmental emissions occurring at manufacturing of new products are reduced. The basic goal striven for in recycling is to separate the different materials contained in waste into separate products which can be used as secondary raw material and which as such have a certain market value. A precondition for successful separation is to achieve liberation of different mutually (mechanically, chemically or thermally) connected materials. The success in recycling electrical and electronic waste depends on the characteristics of waste, the applied separation procedures and devices, and of course on the conditions (values of operating variables of the devices) in which separation is carried out. The first phase of the recycling process consists of manual dismantling and separation of larger parts of waste devices, whereby a larger share of iron, copper, glass and plastic materials is separated. The remaining parts need to be shredded in order to achieve liberation, and thereupon, by appropriate separation procedures, the single types of material shall be separated. In this dissertation beside enclosures and large condensers and cathode tubes containing phosphorus powder and cadmium have been manually separated from TV sets, and due to the impossibility of their save testing have been excluded from further testing. The separated wooden enclosures have been excluded from further testing, since over time contamination has occurred by harmful substances such as chrome, lead, mercury, sulphur, nickel, zinc, etc., whereas plastic enclosures contain brominated burning inhibitors, which even in very small quantities contaminate plastic materials rendering them inappropriate for obtaining new plastic. The remaining material has been divided according to its characteristics into three groups which have been tested separately. The group called „Loudspeakers“ is an integral part of the audio system and it contains the highest quantity of iron and somewhat less copper in yokes, as well as plastic, cardboard and textile. In the group „Yokes, cables, connectors and wires“ copper is represented to a high degree, and the third group of „Printed circuit boards“ contains, in addition to the copper conductor structure, also a lot of rare metals on a nonconductor basis (vitroplast, pertinax). For each of the previously indicated groups a separate test plan has been developed. For all groups shredding has been carried out first, in order to achieve liberation, followed by sieving in order to obtain classes appropriate for tests in individual separators. The test plan for air and electrostatic separation has been developed by using statistical planning of experiments under application of the programme system Statistica (Version 8, StatSoft) according to a central composite design (Central Composite Design), including 17 tests for each class on the individual device. By analysing the variance, the impact of the individual independent variable as well as the impact of the interaction of two (out of the three tested) independent variables on one (out of the two) dependent variables (concentrate quality or mass recovery), along with the assessment of this impact, has been determined. The impact of individual variables in gravitation and magnetic separation has been tested in such a way that the value of one variable was changed, while all the other variables were kept constant. Air separation tests have shown that the height of the compartment barrier has the highest impact on the quality of the concentrate, and airstream speed has the least impact, whereas with regard to the interaction of the variables, the barrier height and the position of the inlet have the highest impact. In all cases the barrier height had the highest impact on recovery. Best results (concentrate quality from 99 % to 100 % with recovery from 80 % to 99 %) were achieved at separation of grain larger than 2 mm (class 4/2 mm and 3,15/2 mm), whereas with reduced grain size separation efficiency decreased as well. By electrostatic separation high quality of concentrate has been achieved in all classes, and best results have been obtained in tests with the coarsest grain class (4/2 mm). In all tests the position of the separation knife had the largest impact on concentrate quality. Regarding interactions of the variables the interaction of the separation knife position with the voltage of the ionising electrode and the drum rotation speed had the highest impact. The results obtained by magnetic separation have shown that in most cases (in particular for coarser grain classes) wet separation is better than dry separation, whereas differences decreased with the decrease in the grain size. Best results of both the wet lowintensity and dry high-intensity separation were achieved with the smallest class, -0,5 mm. Tests of gravity concentration have shown that in order to achieve a better quality of the concentrate of better quality, concentration table should operate with smaller inclinations of the plate. Based on the obtained results a segregation scheme for electronic waste recycling has been proposed. The basic hypothesis of this dissertation, namely that the devices and procedures used in mineral processing can also be used for recycling electrical and electronic waste, has been confirmed by the results of the testing carried out.

U ovom završnom radu predstavljena je problematika crvenog mulja kao odloženog industrijskog otpada velikih količina, ali i velikih potencijala za iskorištavanje kao sekundarne sirovine. Prikazani su primjeri današnje primjene i tehnologije u razvoju, skupa s njihovim nedostatcima i preprekama.

Električni automobili smatraju se ekološkom alternativom automobilima s motorom s unutarnjim izgaranjem zbog smanjenih emisija ispušnih plinova i povoljnijeg utjecaja na okoliš. Iako ovakva vozila nemaju direktne emisije, u pitanje se dovode načini dobivanja električne energije za napajanje vozila, kao i pitanje utjecaja njihovih baterija na okoliš. Recikliranjem baterija dodatno se umanjuje onečišćenje planete i brzo iscrpljivanje sirovina potrebnih za njihovu izradu, stoga je od iznimne važnosti pravovremeno razvijati kvalitetne metode i tehnologiju. Cilj ovog diplomskog rada je prikazati na koji način se postupa s baterijama električnih vozila u Republici Hrvatskoj i u svijetu, postupak i metode recikliranja uz uspješne primjere u inozemstvu te mogućnosti njihove ponovne uporabe. Rad je napravljen uz pomoć tvrtke Rimac Automobili d.o.o., Electric cars are considered to be an environmentally friendly alternative to cars with an internal combustion engine due to reduced exhaust emissions and a more favorable environmental impact. Although such vehicles do not have direct emissions, the ways of obtaining electricity to power vehicles, as well as the issue of the impact of their batteries on the environment, are still questionable. Recycling batteries further reduces planetary pollution and the rapid depletion of the raw materials needed for their production, so it is extremely important to develop quality methods and technology in a timely manner. The aim of this thesis is to show how electric vehicle batteries are handled in the Republic of Croatia and the world, the procedure and methods of recycling with successful examples abroad and the possibilities of their reuse. The thesis was made with the help from Rimac Automobili d.o.o.