A R C H I V E S o f

F O U N D R Y E N G I N E E R I N G

Published quarterly as the organ of the Foundry Commission of the Polish Academy of Sciences

ISSN (1897-3310) Volume 10

Special Issue 2/2010 123 – 128

23/2

ARCHIVES OF FOUNDRY ENGINEERING Vo lume 10 , Spec ia l I ssue 2 /2010 , 123-128

123

Possibilities of Pelletizing and Briquetting of Dusts from Castings Grinding

A. Pribulová a,*, D. Baricová a, P. Futaš a, P. Gengeľ a

a Department of Iron Metallurgy and Foundry, Technical University of Košice , Faculty of Metallurgy, Park Komenského 14, 042 00 Košice, Slovakia

*Corresponding author. E-mail address: alena.pribulova@tuke.sk

Received 20.05.2010; accepted in revised form 05.06.2010

Abstract 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%). Keywords: Environment Protection, Mechanical Properties, Dust from Castings Grinding, Pelletizing and Briquetting, Electric Induction Furnace.

1. Introduction Metallurgy and Foundry Engineering belong to industrial

sectors which use metal wastes (reversible material, iron scrap and steel scrap) in maximal degree but despite of the huge quantity of rich metallic wastes they are still landfill. Dusts from some foundry machines and works belong to these kinds of wastes. In spite of the increased attention that is dedicated this problem, the foundry wastes are still put on the landfill. It causes not only metal losses and degradation of environmental in the dumping place but too a taking of agricultural land.

Authors [1] divide foundry wastes into three basic groups: • Metallic dusts, they include dusts with Fe content over 70%. • Metallic dusts with variable Fe and SiO2 content, the content

of single components is in the interval 10 – 70%.

• Sand wastes with minimum content of SiO2 about 70% and Fe content can not exceed 10%.

From the view of metal content in wastes, the most interesting

are wastes from the first group. To wastes with Fe content higher then 70% belongs dust from grinding of castings. The wastes from castings cleaning is possible to categorize in to the second group. In to the third category the dust from moulding, from sand and core mixtures preparation belong.

The most suitable aggregate for using of foundry dust wastes with Fe content is cupola furnace [2 - 4].

Authors [5] describe experiments with dust collected from more foundry plants. The dust was pelletized and as a binder material a bentonite was used. The most effective content of bentonite was 5 – 6% because of pellets manipulation. The pellets were put in to the cupola furnace charge in the quantity of 1.77 – 3.54%. Achieved results showed that the iron yield was more then

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ARCHIVES OF FOUNDRY ENGINEERING Vo lume 10 , Spec ia l I ssue 2 /2010 , 123-128 126

4. Conclusions

Dust from grinding of castings with high Fe content (89%) is still landfill in Slovakia. The aim of experiments has been to find the cheaper way of agglomeration with minimum amount of binder because of melting in the electric induction furnace.

The results follow from experiments: • Pelletizing with addition of bentonite, water glass and cement

was not successfully. • Briquettes made from dusts from grinding with addition of

water glass got compression strength of 90 kPa but briquettes were very fragile and they were not suitable for transport and handling.

• Melting of briquettes together with cast iron in the electric induction furnace is possible. Iron yield was quite high and quantity of slag was adequate but experiments were made in small induction furnace (10 kg) and it is necessary to make experiments in bigger furnace.

• Briquettes from dust from grinding with bentonite or cupola furnace dust addition that were burnt. Their mechanical properties were excellent but their production would need higher charges.

Acknowledgements This work was supported by the Slovak Research and Development Agency under the contract No.APVV-0180-07

References [1] Melecký J., Petříková R.: Technologie zkusovění

a zpracovaní kovonosných slévarenských odpraškú při výrobě oceli, Slévarenství XXXVIII (1990), z. 6, str. 362 – 368.

[2] Holtzer M., Niesler M., Podrzucki C., Rupniewski M.: Wykorzystanie żeliwiaka do recyklingu pyłów odlewniczych, Archiwum Odlewnictwa, 2006, 6, Nr 20, str. 111 – 121.

[3] Holtzer M.: Możliwości wykorzystania w procesie żeliwiakowym odpadów odlewniczych zawierających żelazo. Przegląd Odlewnictwa 2000, nr 6, str. 236 – 238.

[4] K. Smyksy, M. Holtzer, Possibilities of briquetting process using for cupola dust utilisation, Archiwum Odlewnictwa, 2002, 2, Nr 3, str. 121 – 128.

[5] J.D. Sharp, Recyklace odpadů s obsahem železa ze slévaren litiny, Slévarenství, XLVI, 1998, č. 7 – 8, str. 247 – 250.

Możliwości peletyzacji i brykietowania pyłów

pochodzących ze szlifowania odlewów Streszczenie 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.