Primjena IPPC naputka u ljevačkoj industriji

The paper deals with Integrated Prevention and Pollution Control (IPPC) Directive and its application in foundry industry. The minimization of emissions, efficient raw material and energy usage, optimum process chemical utilization, recovering and recycling of waste and the substitution of harmful substances are all important principles of the IPPC Directive. The following major activities are discussed from the point of view of specific pollution of environment: melting and metal treatment, preparation of moulds and cores, casting of molten metal into the mould, cooling for solidification and removing the casting from the mould, finishing of the raw casting. For foundries the focal points are air emissions, the efficient use of raw materials and energy, and waste reduction, in conjunction with any recycling and re-use options.Rad se bavi integriranim predradnjama i naputkom o kontroli zagađivanja (IPPC) i njenom primjenom u ljevačkoj industriji. Minimalizacija emisija, učinkovita uporaba sirovina i energije, optimalno korištenje kemijskih procesa, oporavljanje i recikliranje otpada, zamjena štetnih tvari, sve su to važna načela IPPC naputka. S točke gledišta specifičnog zagađivanja okoliša raspravlja se o slijedećim glavnim aktivnostima: taljenju, tretiraju metala, pripremanju kalupa i jezgri, lijevanju rastaljenog metala u kalup, hlađenje radi skrućivanja i vađenja odljevka iz kalupa, konačna obrada sirovog odljevka

Primitive erythropoiesis in early chick embryogenesis. II. Correlation between hemoglobin synthesis and the mitotic history.

Primitive erythroblasts in the circulating blood of the chick embryo continue to divide while synthesizing hemoglobin (Hb). Hb measurements on successive generations of erythroblasts show that there is a progressive increase in the Hb content of both interphase and metaphase cells. Furthermore, for any given embryo the Hb content of metaphase cells is always significantly greater than that of interphase cells. The distribution of Hb values for metaphase cells suggests that there are six Hb classes corresponding to the number of cell cycles in the proliferative phase. The location of erythroblasts in the cell cycle was determined by combining Feulgen cytophotometry with thymidine radioautography on the same cells. Measurements of the Hb content for erythroblasts in different compartments of the cell cycle (G1, S, G2, and M) show a progressive increase through the cycle. Thus, the amount of Hb per cell is a function of the number of cell divisions since the initiation of Hb synthesis and, to a lesser degree, the stage of the cell cycle. Earlier generations of erythroblasts synthesize Hb at a faster rate than the terminal generation. Several models have been proposed to explain these findings

The effects of the metal temperature and wall thickness on flake graphite layer in ductile iron

This article addresses the effect of mold filling and wall thickness on the flake graphite layer in ductile iron. The research was conducted for castings with different wall thickness (3-8 mm) and using molding sand with furan resin. A thermal analysis has been performed along the length of the castings to determine the initial temperature of the metal in the mold cavity and the contact time of the liquid metal with the mold. Results demonstrated the strong influence of the temperature decrease of the metal in the mold cavity on the occurrence and the thickness of the flake graphite in the surface layer in ductile iron

Investigations of the Temperature Influence on Formation of Compounds from the BTEX Group During the Thermal Decomposition of Furan Resin / Badania wpływu temperatury na powstawanie związków z grupy BTEX podczas termicznego rozkładu żywicy furanowej

Spoiwa organiczne stosowane w odlewnictwie bazujące na żywicach syntetycznych, z jednej strony wpływają na uzyskanie przez masę formierską odpowiednich właściwości technologicznych a w konsekwencji tego otrzymania dobrych odlewów, a z drugiej w procesach odlewniczych stanowią źródło lotnych związków organicznych (LZO). Wraz z żywicami syntetycznymi stosowane są również ich utwardzacze, których dodatek stanowi wprawdzie niewielki procent w stosunku do masy żywicy, ale związki uwalniane w trakcie ich termicznego rozkładu mogą negatywnie oddziaływać na środowisko naturalne. Zarówno żywice jak i utwardzacze dopiero pod wpływem temperatury towarzyszącej zalewaniu formy ciekłym metalem generują szkodliwe lotne związki organiczne, w tym związki z grupy BTEX. Badania wpływu temperatury na rodzaj oraz ilość związków organicznych powstających podczas termicznego rozkładu wybranych spoiw i utwardzaczy oraz ich mieszanin, pozwalają określić zarówno zakres temperatur najbardziej charakterystycznych dla uwalniania szkodliwych związków, jak również dokonać porównania ich emisji z wybranych materiałów

Automobilski otpad rabljen kao materijal za taline u metalurškim procesima

Increased content of automotive scrap in metallurgical charge raises the content of zinc and lead in the dust from melting installations. Every year 1.2 mln tons of zinc-coated scrap comes to the market to be recycled. The cost of the waste dumping will be systematically growing, this comes refers to both the dumping fee and costs of transport from the plant to the dumping ground. The dust collected in the process of melting is, on one hand, a valuable raw material while, on the other, special processes are required for its effective management. Zinc-containing dust can be processed by two methods: hydrometallurgical refining and pyrometallurgical refining.Povećana količina automobilskog otpada u metalurškim talinama podiže sadržaj cinka i olova u prašini metalurških postrojenja. Svake godine 1.2 mln tona otpada presvučenog cinkom dolazi na tržište radi recikliranja. Troškovi prikupljanja otpada rasti će sustavno. To se odnosi i na troškove spremanja i troškove prijevoza od pogona do mjesta odlaganja. Prašina sakupljana tijekom procesa taljenja, s jedne strane, vrijedan sirovinski materijal, s druge strane, potrebni su posebni postupci za uspješno upravljanje tim otpadom. Prašina koja sadrži cink, može se obraditi na dva načina: hidrometalurškim rafiniranjem i pirometalurškim rafiniranjem