Bijih Besi Dan Aglomerisasi

BIJIH BESI & AGLOMERISASI Prof. Dr.-Ing. Bambang Suharno

Metallurgy and Materials Engineering Department University of Indonesia 2010

University of Indonesia

Bahan Baku Proses Pembuatan Besi Baja  Iron Ore  Reduktor  Coke (Blast Furnace)  Coal (Reduksi Langsung dan Smelting Reduction)  Natural Gas (CH4) (Reduksi Langsung)

 Scrap  Additive (Flux): CaO

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Jenis Bijih Besi (Iron Ore)

 Jenis oksida (terbanyak)  (Fe3O4 ==  Magnetit Magnetit  Fe  Fe ≈ 72,4 % 72 4 % Fe2O3 =  Hematit Fe ≈ 70 %

 Jenis Hidroksida  Fe ≈ 50 % ‐ 55 % Fe2O3.nH2O =  Hydrohematite/Laterit  =  Goethit  Fe2O3*H2O Fe2O3*3 H2O    =  Limonit 

 Jenis karbonat =  Siderit    Siderit  Fe  Fe ≈ 48,2 % 48 2 %

FeCO3

 Jenis Titanious Ferrous  FeO.TiO2

=  Pasir Besi/Ilmenit  Fe ≈ 36,8 %,  Ti ≈ 5‐13 %

 Jenis Sulfit  (FeS2

=  Sulfit  Fe ≈ 46,7 %

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Jenis Bijih Besi

Goethite

Limonite

Hematite Hematite Metallurgy and Materials Engineering Department UI

Magnetite

Hematite

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Karakteristik Mineral Iron Ores

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Chemicals composition of iron ores from various countries (wt %)

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Iron ore production million metric tons (2004)

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Persyaratan Bijih Besi  High Iron content  Minimum Minim m imp impurities rities (S (S, P P, As As, Zn Zn, Pb Pb, Na Na, K K,))  High content of basic oxides in gangue (self fluxing ore)  Minimum derivation in chemicals composition  High reducability  High g strength g  Minimum of fines and narrow size distribution (for a uniform gas flow)

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Sebaran Bijih Besi Lokal University of Indonesia

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Deposit Bijih Besi Indonesia

Jenis Deposit Bijih Besi

Methasomatic Ore

Lateritic

Iron Sand

Sumber Daya Terukur Ton

Lokasi

Lampung, West of Sumatera, 320.462.611 Belitung, west of Kalimantan, Tanalang, Plaihari, dll.

1 391 246 630 1.391.246.630

South of Kalimantan,, Pomalaa,, Halmahera, dll.

South of Java Island Coast, 382.000.000 Sumbar, Bengkulu, NTB, Sulsel dll.

Sumber : Direktorat Mineral Batubara ESDM Metallurgy and Materials Engineering Department UI

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Bijih Besi Sekitar Lampung

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Sebaran Batu Bara Lokal University of Indonesia

1.000 juta ton 3.000 juta ton 10.000 juta ton

20.000 juta ton

“Batubara kualitas Bituminous banyak terdapat di Kalimantan Timur”

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Deposit Batubara University of Indonesia

(sumber C atau CO sebagai zat pereduksi)

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PENINGKATAN NILAI JUAL MULAI BAHAN BAKU SAMPAI PRODUK JADI PADA INDUSTRI BESI BAJA University of Indonesia

800 700

$ / TON

HRC

SLAB

600 500

PIG IRON

400 300 200 100

KONS

ORE

PELET

0 1

2

3

4

5

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PT KRAKATAU STEEL

Bijih besi University of Indonesia

Fe tinggi

Fe rendah Pemurnian

> 6 mm

< 6 mm

konsentrat ( Fe tinggi ) ukuran rendah Aglomerisasi (Pellet , Sinter) > 6 mm

Lump ore Export Blast Furnace = Pig Iron (Hot Metal) Reduksi Langsung = Sponge Iron

Pellet

Ukuran 6 mm  batas undersize yang masih dapat diolah Umumnya berukuran 12 – 30 mm

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Proses pemurnian Bijih Besi  Meningkatkan kandungan Fe pada ‘low grade raw ore”  Memisahkan senyawa yang tidak diinginkan  Penghalusan ukuran bijih besi (< 2 mm) untuk dapat dibuat pellet  Proses yang dilakukan antara lain:     

Washing of ore Crushing/ grinding Gravimetry (Classifier) Magnetic separator Flotation

 Iron ore yang sudah dimurnikan disebut “KONSENTRAT” Metallurgy and Materials Engineering Department UI

Crushing dan Screening University of Indonesia

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Milling dan Spiral Classifier University of Indonesia

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Magnetic Separator Process University of Indonesia

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Bahan Baku Pasir Besi (Raw Material)

• Sumber bahan baku Cipatujah, Tasikmalaya berada di p Ciheras, Cimanuk, Cikaung g Gading. g lokasi: Cidadap,

• • • Cidadap

Ciheras

Cimanuk

Cikaung Gading

Kandungan Fe = 35-40% TiO2 = 5 – 15%

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Konsentrat Pasir Besi (Ore Treatment) Pasir Besi

Magnetic Separator

Konsentrat CMPFA Metalurgi UI

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Spiral Classifier University of Indonesia

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Iron Ore Dressing University of Indonesia

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Pengolahan Latheritic Ore di Indonesia University of Indonesia

 Proses penambangan dan pemurnian dari bijih besi muda (bijih besi laterit) di Indonesia telah dilakukan oleh 2 (dua) perusahaan, yaitu : 1. PT. KRAKATAU STEEL (Persero) - Project began : Oktober 2006 - Kapasitas : 100 ton per hari 2 PT 2. PT. SILO (Sebuku Iron Lateritic Ores) - Project began : 2000 (actual start-up 2003) - Kapasitas : 2,000 – 2,500 ton per hari

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Mining & Processing Operations of Latheritic Ore in Indonesia

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LATERITE IRON ORE

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BIJIH BESI KARUNGAN

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IRON ROCK Metallurgy and Materials Engineering Department UI

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Pengolahan Bijih Besi Sinter

Fe tinggi

Iron ore

Lump ore

Pellet

Blast F’ce

Foundry

Pig Iron

Ukuran halus Fe rendah

First Step : Tentukan

Red Lgsng

Steel Plant

Kualitas dan Kuantitas Cadangan Bijih Besi Metallurgy and Materials Engineering Department UI

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Sponge Iron

Alasan Aglomerisasi  Tidak semua bijih besi memiliki kadar Fe tinggi untuk diolah di tanur tinggi atau tanur lainnya  Ukuran yang seragam diperlukan agar :  optimum rate of gas flow  uniform gas flow , with a minimum of channeling  Ukuran partikel kecil , menyebabkan adanya sejumlah fine material yang keluar tanur dan masuk ke ‘gas recovery’ system

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Proses Aglomerisasi  Kriteria pemilihan  ukuran partikel > 2 mm  sinter  ukuran partikel < 0,2 mm  pellet

 Lokasi Pembuatan  Sinter  biasanya dekat TT  Pellet P ll t  biasanya bi d dekat k t penambangan

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Penggunaan Pellet dan Sinter  Europa Union : 65% sinter, 24% pellet, 13% lump ore  Brazil, Japan, Korea Selatan: > 70% sinter  Canada, USA: 91 dan 81% pellets  Penggunaan Lump ore pada blast furnace dibatasi tak lebih dari 10 – 15%  Pada blast furnace sebetulnya memungkinkan untuk mengolah bijih besi dengan berbagai kadar Fe. Namun semakin tinggi kadar Fe akan semakin ekonomis

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Proses Pembuatan Pellet  Dikembangkan dalam rangka pemanfaatan bijih besi yang halus  Green pellet (pellet mentah)  Partikel bijih besi halus yang dicampur oleh air dan bentonit, digumpalkan melalui proses rotasi sehingga terjadi bola-bola aglomerat (kekuatan 20 – 50 N/ pellet)

 Burn pellet (pellet bakar)  bola-bola aglomerat dikeraskan dengan cara dibakar pada: conveyor belt, grate kiln atau shaft furnace  (kekuatan hingga 2500 N/ pellet)

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Pellet Mentah (Green Pellet) Bijih besi halus dengan campuran Bentonit % air

: :

8,3 8 3 - 10 kg/ ton of feed (4-7%)

ukuran pellet : ± 8 – 30 mm β

 biasanya 10 – 15 mm

Kekuatan Green pellet : 20 – 50 N / pellet

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Pelletasi

Faktor penentu  kadar air harus optimal  kehalusan partikel  penambahan bentonit  kadar bahan sampingan  diameter , kecepatan piringan  jika kekuatan green pellet rendah  dibakar (T = 1000 oC)  agar kekuatan : 2500 N/pellet  Alat :

Shaft furnace Grate kiln Traveling gate / conveyor belt

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Proses Pelletasi

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Parameters of the discs for production of green pellet

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Pellet Bakar (Burn Pellet)  Dibakar 1000 OC, kekuatan : 2500 N/pellet

Grate Kiln

T Traveling li gate t / conveyor belt b lt

Shaft Furnace

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Campuran Sinter  Iron bearing fines ( 50-60% of raw mix, grain sixe 010 mm, incl. 70%> 70% 0,2mm)  Solid fuel (3-4% coke breeze 0-3mm)  Flux (10-15%, grain size