Hasil Pencarian

Ditemukan 173070 dokumen yang sesuai dengan query

Satrio Amarela

Peningkatan kadar dan rasio mangan pada bijih mangan lokal kadar rendah melalui proses benefisiasi dengan variabel temperatur pada reduction roasting = The enhancement of manganese grade and its ratio from local low grade manganese ore through beneficiation process with the variation of temperature on reduction roasting process

"ABSTRAK

Sekitar 90% bijih mangan di dunia digunakan untuk pembuatan ferromangan dan

ferrosilicomangan sebagai material paduan dalam proses steel making. Penambahan

unsur mangan dalam wujud paduan ferromangan pada proses steel making mampu

meningkatkan kekerasan dan ketangguhan baja. Ferromangan diperoleh dari

pengolahan bijih mangan metallurgical grade dengan proses peleburan. Bijih mangan

kadar rendah, melalui penelitian sebelumnya oleh Hendri (2015) dan Noegroho (2016),

tidak ekonomis untuk dilebur menjadi ferromangan 􀁇􀁈􀁑􀁊􀁄􀁑􀀃􀀰􀁑􀀃􀂕􀀙􀀓􀀈􀀃􀁖􀁈􀁋􀁌􀁑􀁊􀁊􀁄􀀃􀁅􀁌􀁍􀁌􀁋􀀃

mangan kadar rendah harus dibenefisiasi terlebih dahulu untuk meningkatkan kadar

mangan dan rasio Mn/Fe dalam bijih.

Bijih mangan kadar rendah pada penelitian ini merupakan bijih mangan lokal asal

Lampung dan Jawa Timur. Benefisiasi dilakukan menggunakan teknik gravity

separation dan reduction roasting selama 30 menit menggunakan 20% batu bara

dilanjutkan magnetic separation pada medan magnet ±500 gauss. Bijih mangan

dihaluskan ke dalam ukuran -20+40, -40+60, dan -60+80 mesh dan temperatur

reduction roasting divariasikan pada 500oC, 700oC, dan 900oC. Pengujian XRD dan

XRF dilakukan dalam mengarakterisasi sampel awal dan hasil.

Rasio Mn/Fe dan kadar mangan pada bijih asal Lampung masing-masing

sebesar 0,90 dan 7,83% sementara pada bijih asal Jawa Timur masing-masing sebesar

1,356 dan 18,52%. Setelah dibenefisiasi, hasil terbaik dari proses gravity separation

pada bijih Lampung tercapai pada rasio Mn/Fe 0,95 dengan kadar Mn 9,4% pada

89,75% recovery berat sementara pada bijih Jawa Timur diperoleh pada rasio Mn/Fe

3,32 dengan kadar mangan 40,48% pada 2,09% recovery berat. Selanjutnya, hasil

terbaik dari reduction roasting dilanjutkan magnetic separation pada bijih Lampung

diperoleh pada rasio Mn/Fe 1,96 dan kadar mangan 6,81% pada 36 wt% recovery,

sementara pada bijih Jawa Timur, tercapai pada rasio Mn/Fe 3,99 dan kadar mangan

34,31% pada 44 wt% recovery.

ABSTRACT

About 90% of manganese ore is utilized for ferromanganese and

ferrosilicomanganese production as alloying metal in the steel making process. The

addition of manganese in the form of ferromanganese to the steel making process is

able to increase hardness and toughness of steel. Ferromanganese is obtained from the

metallurgical grade manganese ore processing through the smelting process. Low grade

manganese ore, according to the previous research from Hendri (2015) and Noegroho

(2016), was not economic for direct smelting to obtain ferromanganese with Mn 􀂕􀀙􀀓􀀈􀀑􀀃

Therefore, low grade manganese ore must be beneficiate first to enhance the

manganese grade and its ratio.

Low grade manganese ore in this research are a local ore from Lampung and

East Java. The steps on the beneficiation process are including gravity separation and

reduction roasting for 30 minutes using 20% of coal followed by magnetic separation

at the magnetic intensity of ±500 Gauss. The particle size was reduced into -20+40, -

40+60, and -60+80 mesh and the temperature of reduction roasting was varied at 500oC,

700oC, and 900oC. XRD and XRF testing was conducted for the characterization of ore

and the sample results.

Mn/Fe ratio and manganese content in Lampung ore is respectively 0.9 and

7.83%, while in East Java ore is respectively 1.356 and 18.52%. After beneficiation,

the best results from gravity separation of Lampung ore was obtained at 0.95 of Mn/Fe

ratio and 9.4% of manganese content at 89.75% of weight recovery, while in East Java

ore was obtained at 3.32 of Mn/Fe ratio and 40.48% of manganese content at 2.09% of

weight recovery. Then, the best results of reduction roasting followed by magnetic

separation of Lampung ore was obtained at 1.96 of Mn/Fe ratio and 6.81% of

manganese content at 36% of weight recovery, while in East Java ore was obtained at

3.99 of Mn/Fe ratio and 34.31% of manganese content at 44% weight recovery.

2016

S63231

UI - Skripsi Membership Universitas Indonesia Library

Muhammad Azhar Hadnyandita

Peningkatan kadar mangan dan rasio mangan/besi dari bijih mangan kadar rendah lokal melalui proses benefisiasi dengan vasriasi waktu reductio roasting = Enhancement of mn fe ratio from local low grade manganese ore through beneficiation with reduction roasting time as a variant

"Mangan merupakan logam ke empat yang paling banyak digunakan di dunia setelah baja, aluminium dan tembaga. Sekitar 95% mangan digunakan untuk kebutuhan metalurgi, yaitu untuk steelmaking dan pembuatan ferroalloys seperti silico-manganese dan ferromanganese. Mangan dapat dikategorikan berdasarkan kandungannya, yaitu bijih mangan kadar rendah (kurang dari 30% Mn), sedang (30%-40% Mn) dan tinggi (lebih dari 40% Mn). Pembuatan ferromangan dengan kadar Mn minimum 60% menggunakan bijih mangan kadar rendah sangat sulit, oleh karena itu perlu dilakukan proses benefisiasi untuk meningkatkan kadar bijih Mn serta rasio Mn/Fe.

Dalam penelitian ini telah dilakukan proses benefisiasi terhadap dua jenis bijih mangan lokal, yaitu bijih mangan asal Lampung dan Jawa Timur. Benefisiasi dimulai dengan crushing dan grinding dua bijih mangan, untuk mereduksi ukuran partikel. Pengaruh ukuran partikel, yaitu -20+40, -40+60 dan -60+80 mesh terhadap proses benefisiasi telah dipelajari dalam penelitian ini. Proses benefisiasi berupa gravity separation dengan menggunakan metode shaking table dilakukan terhadap kedua jenis bijih mangan tersebut. Preliminary test dilakukan setelah gravity separation untuk mengetahui feasibility dari kedua bijih mangan tersebut untuk dilakukan proses benefisiasi tahap selanjutnya, yaitu reduction roasting. Reduction roasting dilakukan terhadap bijih mangan pada suhu 700oC dengan variasi waktu 1 jam, 1,5 jam dan 2 jam. Magnetic separation dilakukan terhadap masing-masing variasi waktu menggunakan magnet dengan kekuatan sekitar 500G.

Hasil yang didapat menunjukkan bahwa ukuran partikel tidak terlalu mempengaruhi rasio Mn/Fe. Kemudian hasil dari gravity separation menunjukkan proses ini tidak efisien terhadap kedua bijih mangan. Pada bijih mangan asal Lampung tidak ada kenaikkan rasio Mn/Fe yang signifikan, lalu pada bijih mangan asal Jawa Timur rasio Mn/Fe naik menjadi 3,3 pada fraksi tailing, namun tailing yang didapat hanya sekitar 2,4% dari feed yang masuk sehingga menyebabkan proses ini tidak ekonomis. Reduction roasting memiliki efek yang penting untuk proses magnetic separation karena dapat mengubah senyawa hematite menjadi magnetite sehingga Fe pada bijih mangan dapat terpisah. Hasil magnetic separation menunjukkan rasio Mn/Fe paling tinggi didapat dalam waktu 1 jam pada ukuran -20+40, yaitu sebesar 6,10 dan menurun seiring semakin halusnya ukuran partikel.

Manganese is the fourth widely used metal in the world after steel, aluminium and copper. For about 95% of Manganese usage is for metallurgical applications, like steelmaking and the productions of ferroalloys, silico-manganese and ferromanganese. Manganese is categorized based on its content, which is low-grade (less than 30% of Mn), medium-grade (30-40% of Mn) and high-grade (more than 40% of Mn). Producing ferromanganese with a minimum content of Mn for about 60% using a low-grade manganese ore is very difficult, therefore beneficiation process is needed to enhance the Mn content and also the Mn/Fe ratio.

In this research, beneficiation processes were conducted to two local low-grade manganese ores, manganese ore from Lampung Province and from East Java Province. Beneficiation starts by crushing and grinding two manganese ores, to reduce the particle size. The effect of particle sizes, which were -20+40, -40+60 dan -60+80 mesh, to the beneficiation processes were studied in this research. Gravity separation using shaking table as a method was the first step of beneficiation process that was conducted to both manganese ores. Preliminary test were done after the gravity separation to understood the feasibility of the two manganese ores that can be processed to the next beneficiation processes, reduction roasting. Reduction roasting was conducted to the manganese ore in 700oC for 1 hour, 1,5 hours and 2 hours as a time variant. Magnetic separation was done by separating every single time variant using a magnet with an intensity about 500G.

The results shows that size fraction or particle size has a negligible effect to the Mn/Fe ratio. The gravity separation results shows that this process is not efficient to the both manganese ores. Lampung Province ore shows that there is no significant of Mn/Fe increment, and for East Java Province ore, Mn/Fe increases to 3.3 in tailing fraction, however the tailing fraction that is gained in this process was only about 2.4% from the feed therefore it?s not economical. Reduction roasting has an important effect for the magnetic separation process because it converts hematite compound to magnetite so the Fe from this ore can be separated. The magnetic separation results shows that the highest Mn/Fe ratio was gained in 1 hour on -20+40 size particle, which is 6.10 and decrease along with decresing the size particle."

Depok: Universitas Indonesia, 2016

S63233

UI - Skripsi Membership Universitas Indonesia Library

Nur Arief Meyviawan

Peningkatan kadar dan rasio pasir kromit kadar rendah melalui proses benefisiasi dengan variabel temperatur dan waktu reduction roasting = Enhancement of low grade chromite sand through beneficiation process with the variation of temperature and time on reduction roasting

"ABSTRAK

Ferokrom (45-75% Cr dan 35-50% Fe) adalah paduan yang sangat penting dalam pembuatan baja tahan karat karena sifat kekuatan dan ketahanan terhadapa korosi yang tinggi. Ferokrom dibuat dari bijih kromit, sumber kromium yang paling ekonomis untuk di eksploitasi, melalui proses peleburan dengan menggunakan submerged arc furnace. Proses benefisiasi dengan metode roasting adalah proses yang digunakan oleh industri ferokrom dengan rasio Cr/Fe sebagai parameter utama dalam menentukan efisiensi operasi. Semakin tinggi nilai rasio Cr/Fe hasil benefisiasi, semakin tinggi efisiensi yang dicapai saat proses peleburan. Tujuan dari penelirian ini adalah untuk mencapai rasio Cr/Fe tertinggi dengan melakukan beberapa parameter selama proses roasting. Separasi magnet menggunakan kuat magnet 500 gauss dilakukan terhadap pasir kromit kadar rendah.

Roasting dilakukan pada temperatur 800, 1000 dan 1200 oC selama 30, 60, dan 90 menit. 100 gram produk non magnet hasil separasi magnet awal digunakan sebagai material utama, 30,6 gram batubara sebagai reduktor dan 10 gram CaCO3 sebagai flux. Separasi magnet dilakukan untuk memisahkan senyawa yang bersifat magnet hasil roasting. Respon dari roasting di lihat dengan X-ray diffraction (XRD), sedangkan efek separasi magnet dievaluasi dengan X-ray fluorescence (XRF). Hasil penelitian ini menunjukkan rasio Cr/Fe tertinggi adalah 1,54 pada roasting 1000 oC selama 60 menit. Terlihat bahwa roasting dapat memisahkan senyawa FeO dari struktur spinel dan separasi magnet dapat mengurangi unsur besi untuk meningkatkan rasio Cr/Fe.

ABSTRACT

Ferrochromium (45-70 % Cr and 35-50% Fe) is a vital alloy mostly used for the production of stainless steel due to its high strength and corrosion resistance. It is produced from chromite ore, the only economically exploitable resource of chromium, through carbo-thermic smelting in submerged arc furnaces. The beneficiation-roasting process of chromite is currently applied as ferrochromium industrial production with the Cr/Fe ratio as the main parameter to determine the efficiency of the operation. The higher Cr/Fe ratio obtained during beneficiation-roasting process, the higher efficiency of smelting would be achieved. The objective of this research is to get the highest Cr/Fe ratio with conducting several parameters during roasting operation. Magnetic separation using 500 gauss of the magnetic intensity was carried out to the low grade chromite ore.

Roasting was conducted at 800, 1000 and 1200 oC for 30, 60 and 90 minutes with the 100 grams of non-magnetic product as the main material, 30.6 gram of coal as reductor and 10 gram of CaCO3 as flux. Afterwards, magnetic separation was reconducted to separate the magnetic constituent. The roasting response was observed by X-ray diffraction (XRD), while the effect of magnetic separation was determined by X-ray fluorescence (XRF). The results showed that the highest Cr/Fe ratio is 1.54, achieved after roasting at 1000oC for 60 minutes. It clearly indicates that roasting process has successfully released the FeO from Spinel Crystal and separation using magnet can decrease the iron constituent in chromite to enhance the Cr/Fe ratio."

2017

S66090

UI - Skripsi Membership Universitas Indonesia Library

Laurensia

Peningkatan kadar dan rasio pasir kromit kadar rendah melalui proses benefisiasi dengan variabel jumlah reduktor batubara dan aditif caso4 pada reduction roasting = The enhancement of chromium grade and its ratio from local low grade chromite sand through beneficiation process with the variation of reductant and caso4 as additive dosage on reduction roasting process

"ABSTRAK

Sekitar 95 dari seluruh bijih kromit yang ditambang di dunia digunakan sebagai bahan baku pembuatan ferrochromium FeCr . Pada penelitian sebelumnya, peleburan pasir kromit kadar rendah tidak dapat menghasilkan ferrochromium dengan kadar Cr ge; 60 sehingga pasir kromit kadar rendah harus dilakukan proses benefisiasi untuk meningkatkan kadar Cr dan rasio Cr/Fe sebelum proses peleburan menjadi ferrochromium. Penelitian ini menggunakan pasir kromit kadar rendah asal Kabupaten Konawe, Sulawesi Selatan. Proses benefisiasi yang dilakukan adalah magnetic separation menggunakan medan magnet 800 Gauss dan reduction roasting selama 60 menit pada temperatur 1000 C dengan variabel jumlah reduktor, yaitu 5 lean carbon, stokiometri, 5 excess carbon dan 10 excess carbon serta jumlah aditif CaSO4, yaitu 5 , 10 , 15 , dan 20 . Rasio Cr/Fe dan kadar Cr pada bahan baku pasir kromit adalah 0,9 dan 19,27 . Kromium dalam pasir kromit kadar rendah berada dalam mineral magnesiochromite, aluminian, yang terasosiasi dengan unsur besi dalam struktur spinel. Magnetic separation yang dilakukan pada bahan baku pasir kromit menghasilkan kenaikan rasio Cr/Fe dan kadar Cr menjadi sebesar 1,31 dan 21,33 akibat adanya pemisahan antara kromit yang bersifat paramagnetik dan pengotornya yang bersifat magnetik. Selanjutnya, hasil terbaik dari reduction roasting yang dilanjutkan dengan magnetic separation diperoleh pada proses reduction roasting dengan menggunakan 10 excess carbon dan 20 CaSO4, yaitu menghasilkan rasio Cr/Fe dan kadar Cr sebesar 1,19 dan 20,48 atau setara dengan FeCr yang mengandung 54,5 Cr.

ABSTRACT

Around 95 of mined chromite ore in the world is utilized as raw material for ferrochromium making process. According to the previous research, the melting of low grade chromite sand could not produce ferrochromium with Cr ge 60 so that low grade chromite sand has to be beneficiated to enhance the chromium grade and Cr Fe ratio before the melting process to produce ferrochromium. This research utilized low grade chromite sand from Konawe District, South Sulawesi. The beneficiation processes that was conducted were magnetic separation, which used magnetic field of 800 Gauss and reduction roasting for 60 minutes at 1000 C with various reductant dosage, 5 lean carbon, stoichiometry, 5 excess carbon and 10 excess carbon along with various dosage of CaSO4 as additive, 5 , 10 , 15 , and 20 . Cr Fe ratio and chromium content in low grade chromite sand are 0.9 and 19.27 . Chromium, in low grade schromite sand, was existed as magnesiochromite, aluminian, which associated with iron in spinel structure. Magnetic sseparation process that was conducted to the raw material, resulted in enhancement of Cr Fe ratio and chromium content to 1.31 and 21.33 due to separation of the paramagnetic chromite from the magnetic gangue. Furthermore, the best result from reduction roasting followed by magnetic separation was obtained when reduction roasting used 10 excess carbon and 20 CaSO4, which resulted at 1.19 of Cr Fe ratio and 20.48 of chromium content or equivalent to FeCr with 54.5 Cr."

2017

S66515

UI - Skripsi Membership Universitas Indonesia Library

Hendri Saputra

Proses pembuatan ferromangan pada submerged arc furnace dengan menggunakan campuran bijih mangan kadar rendah dan kadar menengah = Ferromanganese process using submerged arc furnace with mixed low grade and medium grade manganese ore

"[ABSTRAK

Potensi cadangan bijih mangan di Indonesia cukup besar, namun terdapat

di berbagai lokasi yang tersebar di seluruh Indonesia. Komoditi ini menjadi bahan

baku yang tidak tergantikan di industri baja dunia. Ferromangan (FeMn)

merupakan logam paduan dengan komposisi 75% Mangan (Mn) dan 25% besi (Fe)

yang umumnya digunakan pada proses peleburan besi/baja guna memperbaiki

sifak-sifat mekanik dari produk yang dihasilkan.

Penelitian ini dilakukan untuk mempelajari pengaruh proses pencanpuran

bijih Mn kadar rendah (LG) yang berasal dari Kab. Tanggamus, Lampung (16,3

%Mn-19,2 %Fe-20,2 %Si) dengan bijih Mn kadar menengah (MG) yang berasal

dari Jember, Jawa Timur (27,7 %Mn-4,4 %Fe-14,7%Si) sebagai bahan baku untuk

pembuatan logam FeMn dengan kandungan minimal sebesar 50 %Mn. Penelitian

ini dilakukan sebanyak 5 kali percobaan dengan variasi pada campuran bijih Mn

yaitu [1] 25 %LG+75 %MG, [2] 50 %LG+50 %MG, [3] 75 %LG+25 %MG, [4]

100 %LG, dan [5] 100 %MG. Bijih mangan diproses menggunakan Submerged Arc

Furnace (SAF) dengan input berupa bijih Mn sebagai bahan baku utama, kokas

sebagai reduktor, dan kapur sebagai aditif. Ketiga bahan baku tersebut dilebur

hingga mencapai temperatur 1500 oC. Untuk mengetahui kualitas bahan baku dan

produk FeMn yang dihasilkan, dilakukan analisa seperti XRF (X-Ray

Fluoroscence), XRD (X-Ray Diffraction), AAS (Atomic Absorbtion Spectrometry),

dan Proksimat.

Dari hasil penelitian didapatkan bahwa untuk percobaan [1] diperoleh

logam FeMn sebanyak 5,2 Kg dengan kadar 54,05 %Mn, percobaan [2] diperoleh

logam FeMn sebanyak 4,75 Kg dengan kadar 50,03 %Mn, percobaan [3] diperoleh

logam FeMn sebanyak 4,6 Kg dengan kadar 36,44 %Mn, percobaan [4] diperoleh

logam FeMn sebanyak 4,3 Kg dengan kadar 31,13 %Mn, dan percobaan [5]

diperoleh logam FeMn sebanyak 12,8 Kg dengan kadar 75,19 %Mn. Pengaruh dari

proses pencampuran (Mn-blend) dalam pembuatan ferromangan ini adalah

semakin banyak komposisi bijih Mn kadar menengah (MG) yang digunakan,

menyebabkan (a) semakin banyaknya kokas dan semakin berkurangnya kapur yang

dibutuhkan, (b) meningkatnya yield, jumlah produk, serta kandungan persentase

Mn dari FeMn yang dihasilkan, dan (c) semakin rendahnya konsumsi energi yang

dibutuhkan.

ABSTRACT

The potential reserve of manganese ore in Indonesia is very large, but it

was located in different locations spread throughout Indonesia. Manganese ore is

one of raw material in producing ferromanganese that is not replaceable in the

world steel industry. Ferromanganese (FeMn) is an alloying metal that contained

of 75% Manganese (Mn) and 25% Iron (Fe) which is generally used in the process

of iron/steel making to improve its mechanical properties.

In this experiment, ferromanganese production was conducted by blending

two kinds of manganese ore, that was low grade Mn ore (LG) which derived from

Tanggamus, Lampung (16,3 %Mn-19,2 %Fe-20,2 %Si) and medium grade Mn ore

(MG) which derived from Jember, East Java (27,7 %Mn-4,4 %Fe-14,7 %Si), to

obtain ferromanganese with a minimum content of 50 %Mn. The composition of

Mn-blend in this experiment was [1] 25 %LG+75 %MG, [2] 50 %LG+50 %MG,

[3] 75 %LG+25 %MG, [4] 100 %LG, and [5] 100 %MG. This mixed manganese

ore was processed by using Submerged Arc Furnace (SAF). Cokes and limestone

was added into the furnace as reductant and flux agent, respectively. Those raw

materials are smelted until 1500 °C. To determine the composition of raw materials

and the product of FeMn, analysis such as XRF (X-Ray Fluorescence), XRD (XRay

Diffraction), AAS (Atomic Absorption Spectrometry), and proximate have to be

done.

From each composition of Mn-blend above in this experiment, it was

obtained that [1] 5,2 Kg of FeMn with 54,05 %Mn, [2] 4,75 Kg of FeMn with 50,03

%Mn, [3] 4,6 Kg of FeMn with 36,44 %Mn, [4] 4,3 Kg of FeMn with 31,13 %Mn,

and [5] 12,8 Kg of FeMn with 75,19 %Mn. The effect of Mn-blend in this

ferromanganese production was by the increasing composition of the medium

grade manganese ore (MG) that will cause: (a) the increasing number of cokes and

the decreasing of limestone required, (b) the increasing of yield, the number of

products, and also the percentage of manganese content FeMn, and (c) the

decreasing of energy consumption required., The potential reserve of manganese ore in Indonesia is very large, but it