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Processing and utilization of metallurgical slags

Pribulova A., Futas P., Baricova D.

Production Engineering Archives

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2016

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Vol. 11, No. 2

2--5

EN

Metallurgy and foundry industry create a huge amount of slags that are by-products by production of pig iron, steel and cast iron. Slags are produced in a very large amount in pyrometallurgical processes, and are huge sources of waste if not properly recycled and utilized. With rapid growth of industrialization, the available land for land-filling of large quantity of metallurgical slags is reducing all over the world and disposal cost becomes increasingly higher. Metallurgical slags from different metallurgical processes are treated and utilized in different ways based on the different slag characteristics. The most economic and efficient option for reducing the metallurgical waste is through recycling, which is a significant contribution to saving natural resources and reducing CO2 emissions characteristic of slags and their treatment and utilization are given in the paper. Slags from pig iron and steel production are used most frequently in building industry. From experiments using blast furnace slag and granulated blast furnace slag as grave an water glass as binder follows that the best results – the best values of compression strength and tensile strength were reached by using of 18% of water glass as solidification activating agent. according to cubic compression strength, mixture from 50% blast furnace gravel, 50% granulated blast furnace slag and 18% water glass falls into C35/45 class of concretes. This concrete also fulfils strength requirements for road concrete, it even exceeds them considerably and therefore it could find an application in construction of road communications or in production of concrete slabs.

2

Use of Specific Properties of Zinc Ferrite in Innovative Technologies

Kmita A., Pribulova A., Holtzer M., Futas P., Roczniak A.

Archives of Metallurgy and Materials

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2016

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Vol. 61, iss. 4

2141--2146

EN

Zinc ferrite ZnFe2O4 both in the micro and nano scale is widely used in various fields. The article discusses the structure of this compound and its properties in the nanoscale, which is clearly different from those which the ferrite shows in the microscale. The properties of dust generated electric arc furnace, which can contain up to 40% zinc, substantially in the form of ZnFe2O4 are disscused here. Specific properties (electric, magnetic, thermal) of zinc ferrite nanoparticles determine the very wide possibilities of their use, inter alia as catalysts, absorbents, gas sensors, and a tool to combat cancer.

3

Elimination of Chunky Graphite in Castings with Large Thermal Points

Futas P.

Archives of Foundry Engineering

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2016

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Vol. 16, iss. 4

57--60

EN

The presence of the chunky graphite is unwanted in the cast iron with the spheroidal graphite for this significantly lowers the properties of the ductile iron. This shape of the graphite is formed as the result of the slow cooling rate of the castings with large thermal point and also due to the presence of the elements which suppress the formation of the spheroidal graphite and support formation of the chunky graphite. The spheroidal graphite present in the ductile iron assures the excellent mechanical properties, while the chunky graphite significantly reduces those properties of the ductile iron. Therefore it is of importance to assume conditions under which prevented is the formation of the chunky graphite. The casts were carried out under the conditions of the regular operation of the foundry and tested were various types of modifiers and inoculators and also pre-inoculators containing the elements suppressing the formation of the chunky graphite (Al, Sb a Ba). Applied were also the chromium breaker core to suppress the formation chunky graphite which was present in the structure in the places after the feeders elimination. As whole, executed were eight casts with various types of the modifiers and inoculators.

4

Possibilities of pelletizing and briquetting of dusts from castings grinding

Pribulova A., Baricova D., Futas P., Gengel P.

Archives of Foundry Engineering

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2010

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Vol. 10, iss. 2 spec.

123--126

EN

Foundry dust can be divided into three groups: metallic dust with Fe content over 70%, mixed dust with Fe or SiO2 content between 10–70% and sand wastes with minimum content of SiO2 about 70%. Dust from castings grinding with high Fe content (87.9%) is still landfill in Slovakia. The aim of experiments with dust from grinding has been to find the cheapest way of dust agglomeration with minimum amount of binder because of melting in the electric induction furnace. The dust was pelletized and briquetted and as binders bentonite, water glass and cement were used. Briquettes made from dust from grinding with addition of water glass got compression strength after three months on the air about 82 kPa. Briquettes with addition of water glass were melted together with cast iron in electric induction furnace. Yield of metal from briquettes was around 80% and slag quantity around 4% (without briquettes the slag quantity was 1.4%).

PL

Pyły generowane w odlewni można podzielić na 3 grupy: pyły metaliczne zawierające ponad 70% Fe, pyły stanowiące mieszaninę Fe i SiO2 w ilości 10-70% oraz pyły o minimalnej zawartości SiO2 około 70%, będące odpadem. Pyły ze szlifowania zawierające około 88% żelaza na Słowacji wciąż są wywożone na składowisko. Celem pracy było opracowanie taniej metody aglomeracji tych pyłów, aby można je było przetapiać w piecu indukcyjnym. Pyły poddawano paletyzacji i brykietowaniu, a jako spoiwa stosowano szkło wodne, bentonit ora cement. W wyniku przeprowadzonych badan stwierdzono, że paletyzacja pyłów z proponowanymi spoiwami nie spełniła swojego zadania. Brykiety sporządzane z pyłów ze szlifowania odlewów z dodatkiem szkła wodnego uzyskiwały wytrzymałość na ściskanie rzędu 90 kPa, ale były bardzo kruche i nie nadawały się do transportu. Możliwe jest stosowanie dodatku brykietów do wsadu przy topieniu żeliwa w piecu indukcyjnym uzyskując stosunkowo wysoką wydajność (piec o pojemności 10 kg). Jednak należy przeprowadzić próby w piecu o większej pojemności.