Vol 7, No 3 (2016) > Metalurgy and Material Engineering >

The Effect of Reduction Time and Size Distribution of Mixed Iron Ore with Coconut Shell Charcoal on the Percentage of Metallization by using a Rotary Kiln

Soesaptri Oediyani, Kustiarana Willyandhika, Suharto Suharto

 

Abstract:

Steel is an important material
that is widely used and its development has
occurred in
conjunction with the history of mankind over the last two centuries. In general, the steelmaking process has been
done through a combination of a direct
reduction process and an Electric Arc Furnace (EAF) or
an indirect reduction process and a
Basic Oxygen Furnace (BOF).
The combination of the steelmaking processes
can be adapted to the specific conditions of Indonesian
local iron ore. In Indonesia, the raw material reserves of iron and steel making are
quite large, but spread over several islands. UPT BPML LIPI in cooperation with
the Department of Metallurgical Engineering UNTIRTA conducted research to
improve the economic value of the local iron ore in South Lampung Regency. The total amount of primary iron
ore resources in South Lampung is
estimated to be in the region of 11 million tons. South Lampung Regency iron
ore is primary iron ore with a content of pure magnetite and
magnetite-containing impurity silica levels ranging from 40-65% Fe in total.  South
Lampung Regency low-grade iron ore has the potential to
be reduced by using a rotary kiln. A rotary kiln is a tool used to reduce
low-grade iron ore and produce sponge iron with a high metallization. This process is in accordance with the
Indonesian government policies that regulate the minimum value of percentage of
sponge iron metallization for export, i.e. 85%. In this research, sponge iron is made of a mixture of Lampung iron ore pellets with coconut shell charcoal as a
reduction agent. The composition of coconut
shell charcoal is about 20%, which will determine the optimum amount of South Lampung iron ore pellets in the mixture. In addition, during the reduction process, the residence time of pellets
in the rotary kiln is observed in order to obtain the optimal
percentage of metallization. The method used in this research was the direct
reduction process using a pilot-scale rotary kiln with the variables related to residence time (1, 2 and 3
hours) for
the pellets and to the diameter of the pellets
(-12+8mm and  -20+12mm). Meanwhile, the reduction temperature was
fixed, i.e. 1100oC. The maximum metallization of sponge iron achieved
at a residence time of 3 hours was 99.50% for the average pellet diameter of (-12+8mm).

Keywords: Coconut shell charcoal; Direct reduction; Percent metallization; Rotary kiln; Sponge iron

Full PDF Download

References


Anonymous, 2014. Peraturan Menteri Energi dan Sumber Daya Mineral Republik Indonesia No.1 Tahun 2014 tentang Peningkatan Nilai Tambah Mineral Melalui Kegiatan Pengolahan dan Pemurnian Mineral di Dalam Negeri (in Bahasa)

Arabinda, S., Bidyapati, S., 2011. Alternative Routes to Iron Making. New Delhi: PHI

Deqing, Z., 2010. Direct Reduction Behaviors of Composite Binder Magnetite Pellets in Coal-based Grat-rotary Kiln Process. School of Mineral Processing and Bioengineering, Shangsha, China

Direct Reduction of Iron Ore. Outotec. Available online at http://www.outotec.com/en/About-us/Our-technologies/Direct-and-smelting-reduction/Direct-reduction-of-iron/#tabid-2, accessed on February 4, 2016 at 6.39 p.m

Ishlah, T., 2008. Potensi Bijih Besi dalam Kerangka Pengembangan Klaster Industri Baja. Available online at http://www.bgl.esdm.go.id/publication/index.php/dir/.../503

Kisman, Sutisna, Deddy T., 2005. Inventarisasi dan Evaluasi Mineral Logam di Daerah Kabupaten Lampung Timur dan Selatan, Provinsi Lampung. Available online at http://psdg.bgl.esdm.go.id/index.php?option=com_content&view=article&id=196&Itemid=233

Lubis, Ganie, Surowidjojo, 2014. Indonesia Implements Raw Material Export Restrictions. Available online at http://www.lgsonline.com/pages/g/lgs52ddf7347e933

Pelton, D.A., Christopher, W.B., 2000. Direct Reduced Iron Technology and Economics of Productions and Use. Warrendale: The Iron and Steel Society

Rosenqvst, T., 1983. Principles of Extractive Metallurgy. Singapore: McGraw- Hill

Ross, H.U., 1980. Physical Chemistry: Chapter 3 Direct Reduced Iron Technology and Economics of Productions and Use. Warrendale: The Iron and Steel Society of AIME

Soesaptri, O., 2009. Pemanfaatan Bijih Besi Lokal, Fines Pellet, dan Scale Sebagai Bahan Baku Alternatif Pembuatan Besi Spons dengan Variasi Reduktor. Jurnal Teknika .Volume 5(1), (in Bahasa)

Sun, S.S., 1997. A Study of Kinetics and Mechanism of Iron Ore Reduction in Ore/Coal Composites. Canada: McMaster University

Taein, K., 2007. Characterizing Swelling Behaviour of Iron Oxides during Solid State Reduction for COREX Application and their Implications on Fines Generation. The Iron and Steel Institute of Japan, Volume 47(1), pp. 1590–1598

Winzenried, S., Adhitya, F., 2014. Export Ban on Unprocessed Minerals Effective 12 January 2014- Three-Year Reprieve for Some, But Uncertainty Remains. PwC Indonesia: Energy, Utilites & Mining NewsFlash