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"Penelitian ini dilakukan untuk menyelidiki pengaruh sulfur yang terkandung dalam batubara antrasityang digunakansebagai reduktoruntuk proses reduksi selektifmenggunakan bijih nikel laterit. Proses reduksi dilakukan dalam berbagai variasi temperatur(950 °C, 1050 °C, dan 1150 °C).Bijih nikel laterit yang digunakan dalam penelitian ini adalah bijih nikel sarpolitik dengan kadar Ni 1,74% dan kadar Fe 30%. Jenis reduktor yang digunakan adalah batubara antrasit 2,68%S dan batubara antrasit 5%S. Penggunaan reduktor divariasikan dengan jumlah stoikiometri dari 0,0625-0,25. Penelitian ini juga menggunakan natrium sulfat (Na2SO4) sebagaiaditifdengan komposisi campuran 10% berat dari bahan baku utama. Hasil reduksi kemudian dipisahkan antara konsentrat dengan tailing menggunakan metode separasi magnetik. Hasil pengujian menunjukkanbahwa peningkatan temperatur reduksi dapat menyebabkan peningkatan kadar dan recovery nikel. Hasil pengujian juga menunjukkanbahwa penggunaan reduktor antrasit 2,68% S pada stoikiometri 0,25 menghasilkan kadar dan recoverynikel yang paling optimal.

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This study is conducted to investigate the effect of sulfur contained in the anthracite coal that was used as a reductant for the selective reduction process using saprolitic nickel ore. The reduction process is carried out in various temperature variations of 950ºC, 1050ºC, and 1150ºC.The saprolitic nickel ore was used in this experiment containing 1,74% Ni and 30% Fe. The anthracite coal with different sulfur content, i.e., 2.68%S and 5%S, was used as a reductant in this experiment. The addition of reductants is varied with a stoichiometric amount of 0.0625-0.25. This research also used 10 wt.% of sodium sulfate (Na2SO4) as an additive. Samples that have been reduced were then separated into the concentrate and the tailings using the magnetic separation method. The study resulted that an increase in temperature reduction has increased in nickel content and recovery. The study also suggested that the use of 2.68% S anthracite coal as a reductant at 0.25 stoichiometry produced the most optimal nickel content and recovery."

"[ABSTRAK

Logam ferromangan adalah salah satu unsur paduan penting pada baja

untuk meningkatkan sifat mekanis, ketahanan aus, dan kekerasannya. Bentuk

ferromangan (FeMn) telah diatur dalam standard ASTM dengan kadar minimal

sebesar 75% Mangan (Mn). Tujuan penelitian ini adalah pembuatan logam FeMn

dengan kandungan minimal 60%Mn dari bijih mangan lokal dan mempelajari efek

dari basasitas terak yang dipengaruhi oleh penambahan kapur sebagai zat aditif

dalam proses pembuatan ferromangan terhadap jumlah produk ferromangan yang

dihasilkan dan konsumsi energi yang dibutuhkan dalam proses tersebut.

Dalam penelitian ini digunakan bijih mangan lokal kadar menengah dari

daerah Jember-Jawa Timur 39.38 Mn ? 2.89 Fe ? 26.58 SiO2 (Medium Grade Ore)

dengan teknologi Mini Sub-merged Arc Furnace (SAF) di UPT BPM LIPI,

Lampung. Setiap satu kali proses, digunakan 30 kg bijih mangan (Ø ±30mm), 7.5

kg kokas, dan jumlah batu kapur yang bervariasi, yaitu; 8, 10, 12, dan 14 kg.

Proses peleburan berlangsung pada temperatur 1200-1500 oC. Kemudian hasil

akan dianalisa dengan menggunakan XRF (X-Ray Fluoroscence), XRD (X-Ray

Diffraction), AAS (Atomic Absorbtion Spectrometry), dan Proksimat.

Hasil penelitian menunjukan bahwa dengan meningkatnya basasitas terak

(dari 0.32 hingga 0.76) akan meningkatkan jumlah produk ferromangan hingga 8.2

kg FeMn, kemudian memaksimalkan kadar % mangan yang tereduksi pada logam

hingga mencapai komposisi kimia yang optimal (78,13 Mn-12,65 Fe-8.93 Si),

menekan konsumsi energi hingga 9.8 kwh/kg ferromangan, menekan angka

konsumsi elektroda, dan menghasilkan prosentase efisiensi proses berupa % yield

yang cukup tinggi yakni sebesar 58.61%. Hasil lain yang menunjang proses

pengolahan ferromangan dengan meningkatnya hasil basasitas terak adalah

tercapainya suhu reaksi yang tinggi yakni sebesar 15940C sehingga membuat

reduksi oksida mangan pada terak menjadi mangan pada logam semakin baik,

kemudian jumlah terak juga dapat ditekan. Selanjutnya secara tinjauan aspek

ekonomi dari keempat kali proses penelitian, maka didapatkan hasil yang paling

menguntungkan sebesar Rp 5.731,-/proses.

ABSTRACT

Ferromanganese metal is an important alloying element in steel production

industry used to maximize its mechanical properties such as wear resistance and

hardness. The most common form of ferromanganese according to ASTM standard

contain min.75%Mn and max.25%Fe inside the product. The target of this research

is to obtain ferromanganese metal with min.60%Mn using medium grade

manganese ore (39.38 Mn ? 2.89 Fe ? 26.58 SiO2) from Jember district - East Java,

yet the effect of its slag basicity will also support the most optimum result. This kind

of basicity will determined by the amount of limestone as fluxing agent which added

to the furnace. Moreover, this study will focus to the effect of its slag basicity on the

number of ferromanganese product and the amoung of energy consumption.

This study was taking place at UPT BPM LIPI Lampung, Sumatera. Using

their Mini Sub-merged Arc Furnace (SAF) the process began without any

beneficiation processs for its raw material. Manganese ore Ø ±30mm, cokes, and

limestones were added at the same time to the SAF and melted at 1200-1450 oC.

Processes were repeated 4 times with each process using 30 kg manganese ore, 7.5

kg cokes, and limestones which varied from 8, 10, 12, and 14 kg. Validity of this

study supported by the chemical analysis which took place before and after

reduction process using some tools such as XRF (X-Ray Fluoroscence), XRD (XRay

Diffraction), AAS (Atomic Absorbtion Spectrometry), and Proxymate analysis.

The result of this research showed an increasing trend in product?s quality

as the slag basicity and the amount of limestone increased. As the slag basicity

increase, the number of ferromanganese metal products were also increased until

8.2 kg FeMn and the amount of manganese element in metal phase also showed the

most optimum chemical composition of ferromanganese metal (78,13 Mn-

12,65 Fe-8.93 Si). Furthermore, the energy consumption can be reduced until 9.8

kwh/kg FeMn as well as the electrodes consumption and also the efficiency

percentage or % yield process can be increased up to 58.61%. Other parameters

which used to support these 4-times-research plan was the temperature level which

turned out to be as high as 15940C and helped the reduction process of manganese

oxide into manganese metal became easier. Not only to obtain more manganese

content in metal phase, but also this level of reduction temperature can reduced the

amount of slag. Finally, in addition to support the optimum data, economic analysis

also showed that this composition was the most profitable process with Rp 5.731,-

/process as its profit., Ferromanganese metal is an important alloying element in steel production

industry used to maximize its mechanical properties such as wear resistance and

hardness. The most common form of ferromanganese according to ASTM standard

contain min.75%Mn and max.25%Fe inside the product. The target of this research

is to obtain ferromanganese metal with min.60%Mn using medium grade

manganese ore (39.38 Mn – 2.89 Fe – 26.58 SiO2) from Jember district - East Java,

yet the effect of its slag basicity will also support the most optimum result. This kind

of basicity will determined by the amount of limestone as fluxing agent which added

to the furnace. Moreover, this study will focus to the effect of its slag basicity on the

number of ferromanganese product and the amoung of energy consumption.

This study was taking place at UPT BPM LIPI Lampung, Sumatera. Using

their Mini Sub-merged Arc Furnace (SAF) the process began without any

beneficiation processs for its raw material. Manganese ore Ø ±30mm, cokes, and

limestones were added at the same time to the SAF and melted at 1200-1450 oC.

Processes were repeated 4 times with each process using 30 kg manganese ore, 7.5

kg cokes, and limestones which varied from 8, 10, 12, and 14 kg. Validity of this

study supported by the chemical analysis which took place before and after

reduction process using some tools such as XRF (X-Ray Fluoroscence), XRD (XRay

Diffraction), AAS (Atomic Absorbtion Spectrometry), and Proxymate analysis.

The result of this research showed an increasing trend in product’s quality

as the slag basicity and the amount of limestone increased. As the slag basicity

increase, the number of ferromanganese metal products were also increased until

8.2 kg FeMn and the amount of manganese element in metal phase also showed the

most optimum chemical composition of ferromanganese metal (78,13 Mn-

12,65 Fe-8.93 Si). Furthermore, the energy consumption can be reduced until 9.8

kwh/kg FeMn as well as the electrodes consumption and also the efficiency

percentage or % yield process can be increased up to 58.61%. Other parameters

which used to support these 4-times-research plan was the temperature level which

turned out to be as high as 15940C and helped the reduction process of manganese

oxide into manganese metal became easier. Not only to obtain more manganese

content in metal phase, but also this level of reduction temperature can reduced the

amount of slag. Finally, in addition to support the optimum data, economic analysis

also showed that this composition was the most profitable process with Rp 5.731,-

/process as its profit.]"

"[ABSTRAKMangan merupakan logam yang digunakan untuk berbagai macam kebutuhan seperti untuk campuran logam agar menghasilkan baja dalam industri baja. Kebutuhan bijih mangan juga meningkat seiring dengan peningkatan teknologi dan kebutuhan akan mangan tersebut. Pada penelitian ini akan dilakukan proses pembuatan ferromangan dari bahan baku bijih mangan lokal dengan menggunakan submerged arc furnace (SAF). Proses peleburan dilakukan dengan menggunakan 30kg bijih mangan, 12kg batu kapur, dan jumlah kokas serta batu bara yang bervariasi, yaitu 0%, 25%, 50%, 75%, dan 100%. Kemudian, analisa karaktrisasi akan dilakukan untuk mengetahui kualitas produk ferromangan yang dihasilkan, yaitu analisa XRF (X-Ray Fluoroscence), XRD (X-Ray Diffraction) untuk mengecek kadar mangan dan kadar slag, analisa masa selama proses produksi, dan analisa jumlah pemakaian energi selama proses produksi.Hasil penelitian menunjukkan dengan peningkatan kadar kokas dibandingkan kadar batu bara dapat meningkatkan kualitas maupun kuantitas produk ferromangan. Dengan penggunaan 9.5kg (100%) coke akan menghasilkan massa/yield tertinggi yaitu 12.8kg / 96.24% karena kokas memiliki unsur yang lebih baik daripada batu bara sehingga proses reduksi dapat menjadi optimal. Selanjutnya, kandungan mangan pada produk ferromangan tertinggi saat penggunaan 9.5kg (100%) coke sebesar 75.19% Mn karena kokas memiliki kandungan unsur pengotor yang lebih sedikit dibandingkan dengan batu bara sehingga proses reduksi berlangsung dengan optimal. Kemudian, konsumsi energy terendah saat penggunaan 9.5kg (100%) coke sebesar 7.03KWh/kg karena kokas memiliki kandungan pengotor yang sedikit, salah satu contohnya volatile matter, jika kandungan unsur tersebut besar maka konsumsi energi akan bertambah. Sedangkan kandungan fosfor dan sulfur terendah pada produk ferromangan ketika penggunaan 9.5 kg (100%) coke, yaitu fosfor dibawah 0.001% dan sulfur 0.18%. Pengaruh kandungan tersebut berasal dari reduktor yang digunakan, kokas memiliki kandungan phosphorus dan sulphur yang lebih rendah jika dibandingkan dengan kokas. Phosphorus dapat membuat rapuh logam karena adanya perbedaan kekerasan, kekuatan, dan keuletannya. Sedangkan sulphur dapat membuat rapuh logam pada saat temperature tempa, sehingga kemampuan tempanya akan menurun. Selain itu berdasarkan aspek ekonomi, diperoleh hasil yang memilik keuntungan tertinggi sebesar Rp62,565 dengan penggunaanreduktor sebanyak 9.5kg (100%) coke dan 0kg (0%) coal.ABSTRACTManganese mineral is one of the metal element which are used in common to produce alloy steel product. Manganese element is important to enhance steel properties such as wear resistance and hardness. Due to high demand of alloy steel, the production of ferromanganese products are also increase. This phenomena leaded to a large number of manganese ore supply. In this present study, the ferromanganese production will be conducted in mini submerged arc furnace (SAF) technology. The process began with 30 kg medium grade manganese ore from Jember, East Java-Indonesia, 12 kg limestone as its fluxing agent, and with the main variable of mixed reductor from 0%, 25%, 50%, and 100% of cokes and coal as its balance. Along the process, chemical analysis also conducted with some tools to obtain an accurate data of chemical compositions within the raw materials, slag, and ferromanganese product. These chemical analysis were conducted by XRF, XRD, and Proximate analysis. Furthermore, not only the chemical composition but also the number of electricity in each process were calculated to obtain the most efficient process.The result of this research showed an increasing trend in ferromanganese quality and quantity with a large number of cokes. Instead of coal, cokes are more effective as a reductor agent in this process. This study showed that with 9.5 kg of cokes (100%) the reduction process of ferromanganese will produce 12.8 kg of ferromanganese metal, 75.19% of manganese content, 96.24% of yield ratio, and least number of energy consumption 7.03 kwh/kg ferromanganese product. One of the reasons to support this result is because cokes have lesser number of impurities than in coal such as volatile matter. The amount of phosphor and sulfur content in ferromanganese metal also can be reduced to < 0.001% P and 0.18% S by using 100% cokes as its reductor. These parameters are important because with small number of phosphor and sulfur content the metal will become tougher and hinder the negative effect of short red hardness in metal during further forming activity. The other reason to support the effectiveness of using 100% cokes as the reductor instead of mixing with coal is the amount of profit for each process which is turned to be the highest profit number compare to other mixing composition, it is Rp 62.565,-/process., Manganese mineral is one of the metal element which are used in common to produce alloy steel product. Manganese element is important to enhance steel properties such as wear resistance and hardness. Due to high demand of alloy steel, the production of ferromanganese products are also increase. This phenomena leaded to a large number of manganese ore supply. In this present study, the ferromanganese production will be conducted in mini submerged arc furnace (SAF) technology. The process began with 30 kg medium grade manganese ore from Jember, East Java-Indonesia, 12 kg limestone as its fluxing agent, and with the main variable of mixed reductor from 0%, 25%, 50%, and 100% of cokes and coal as its balance. Along the process, chemical analysis also conducted with some tools to obtain an accurate data of chemical compositions within the raw materials, slag, and ferromanganese product. These chemical analysis were conducted by XRF, XRD, and Proximate analysis. Furthermore, not only the chemical composition but also the number of electricity in each process were calculated to obtain the most efficient process.The result of this research showed an increasing trend in ferromanganese quality and quantity with a large number of cokes. Instead of coal, cokes are more effective as a reductor agent in this process. This study showed that with 9.5 kg of cokes (100%) the reduction process of ferromanganese will produce 12.8 kg of ferromanganese metal, 75.19% of manganese content, 96.24% of yield ratio, and least number of energy consumption 7.03 kwh/kg ferromanganese product. One of the reasons to support this result is because cokes have lesser number of impurities than in coal such as volatile matter. The amount of phosphor and sulfur content in ferromanganese metal also can be reduced to < 0.001% P and 0.18% S by using 100% cokes as its reductor. These parameters are important because with small number of phosphor and sulfur content the metal will become tougher and hinder the negative effect of short red hardness in metal during further forming activity. The other reason to support the effectiveness of using 100% cokes as the reductor instead of mixing with coal is the amount of profit for each process which is turned to be the highest profit number compare to other mixing composition, it is Rp 62.565,-/process.]"

"[Kurangnya penguasaan teknologi pengolahan bijih mangan menjadi ferromangan merupakan salah satu penyebab tingginya impor ferromangan yang dilakukan oleh industri baja nasional. Kualitas produk ferromangan dan juga pencapaian konsumsi energi listrik yang effisien per Kg ferromangan yang dihasilkan menjadi faktor penting pengembangan teknologi ini. Jumlah batubara sebagai reduktor merupakan salah satu parameter utama kesuksesan produksi yang nantinya akan dilihat berdasarkan kualitas FeMn (Kadar Mn hingga 75%) dan seberapa besar power consumption-nya. Pada penelitian ini akan dilakukan proses pembuatan ferromangan dari bahan baku bijih mangan local dengan menggunakan SAF (Submerged Arc Furnace). Variabel yang akan dipakai adalah jumlah batubara sebagai reduktor, yaitu 40.33%, 47%, 53.67%, dan 60.33%. Karakterisasi produk menggunakan XRF (input dan ouput produk), XRD (Mn Ore), dan Proksimat analisis (batubara).Hasil penelitian menunjukan dengan kenaikan jumlah reduktor maka massa produk, kadar mangan, yield product, massa off gas, konsumsi energi, dan persentase fosfor dan sulfur akan meningkat pula. Jumlah produk ferromangan tertinggi didapat pada angka 9.1 kg dengan menggunakan batubara 53.67%. kadar Mn tertinggi didapat pada angka 72% dengan pemakaian batubara 53.67% dan kadar terkecil yaitu 63.12% dengan pemakaian batubara 40.33%. Off gass tertinggi pada angka 33.5 kg dengan pemakaian batubara 60.33% menunjukkan proses reduksi yang tidak optimal, dimana proses reduksi tidak berjalan sempurna. Energi yang paling tinggi di dapatkan pada berat batubara 40.33% yaitu 12.45 Kwh/Kg FeMn, sedangkan yang paling optimum dari segi energi, yaitu didapatkan pada berat batubara 47% dengan 7.56 Kwh/Kg FeMn. %P yang paling tinggi dengan pemakaian batubara 53.67% dengan hasil 0.74% fosfor. Sedangkan untuk %S yang paling tinggi dengan pemakaian batubara 16.1 Kg dengan hasil 0.9% sulfur. Batubara dengan persentase 47% merupakan yang paling optimum apabila dilihat dari aspek ekonomi, %P %S, konsumsi energi, dan kadar mangan.;Due to lack of knowledge and capability to develop new technology for reduction of ferromanganese metal, the number of imported ferromanganese are also increasing in Indonesia. This present study will carried out new perspective to produce ferromanganese metal from Indonesian local manganese ore itself to maintain the demand of ferromanganese product for local industries. The experiment will based on medium grade manganese ore from Jember, East Java ? Indonesia and using mini submerged arc furnace (SAF) as its technology to reduce manganese ore into ferromanganese metal. Influence of various number of coal as its reductor agent have been ninvestigated. The optimized parameter has been established to obtain maximum yield. The experiments with 30 kg of manganese ore, 12 kg of limestone, and various number of coal ranging from 40.33%, 47%, 53.67%, and 60.33% have been carried out. The efforts have also been made to reduce the electrical consumption and the cost of production by using coal instead of cokes.The result showed that an increase in number of reductor increases the amount of product, manganese content, yield ratio, mass of offgas, energy consumption, phosphorus and sulfur content. Biggest number of ferromanganese which can be produced is 9.1 kg with 72% manganese content inside the metal from 53.67% coal and the smallest manganese content is 63.12%Mn from 40.33% coal. Biggest number of off gasses is 33.5 kg which came from 60.33% coal and this phenomena showed that reduction process is not efficient. Highest energy consumption came from 40.33% coal which is 12.45 kwh/kg FeMn product, and the most efficient energy is produced by 53.67% coal which is 7.56 kwh/kg FeMn product. Biggest phosphorus and sulfur content came from 53.67% coal which is 0.74%P and 0.9%S. As the last result, the most optimum research has been carried out by 47% of coal.;Due to lack of knowledge and capability to develop new technology for reduction of ferromanganese metal, the number of imported ferromanganese are also increasing in Indonesia. This present study will carried out new perspective to produce ferromanganese metal from Indonesian local manganese ore itself to maintain the demand of ferromanganese product for local industries. The experiment will based on medium grade manganese ore from Jember, East Java ? Indonesia and using mini submerged arc furnace (SAF) as its technology to reduce manganese ore into ferromanganese metal. Influence of various number of coal as its reductor agent have been ninvestigated. The optimized parameter has been established to obtain maximum yield. The experiments with 30 kg of manganese ore, 12 kg of limestone, and various number of coal ranging from 40.33%, 47%, 53.67%, and 60.33% have been carried out. The efforts have also been made to reduce the electrical consumption and the cost of production by using coal instead of cokes.The result showed that an increase in number of reductor increases the amount of product, manganese content, yield ratio, mass of offgas, energy consumption, phosphorus and sulfur content. Biggest number of ferromanganese which can be produced is 9.1 kg with 72% manganese content inside the metal from 53.67% coal and the smallest manganese content is 63.12%Mn from 40.33% coal. Biggest number of off gasses is 33.5 kg which came from 60.33% coal and this phenomena showed that reduction process is not efficient. Highest energy consumption came from 40.33% coal which is 12.45 kwh/kg FeMn product, and the most efficient energy is produced by 53.67% coal which is 7.56 kwh/kg FeMn product. Biggest phosphorus and sulfur content came from 53.67% coal which is 0.74%P and 0.9%S. As the last result, the most optimum research has been carried out by 47% of coal., Due to lack of knowledge and capability to develop new technology for reduction of ferromanganese metal, the number of imported ferromanganese are also increasing in Indonesia. This present study will carried out new perspective to produce ferromanganese metal from Indonesian local manganese ore itself to maintain the demand of ferromanganese product for local industries. The experiment will based on medium grade manganese ore from Jember, East Java – Indonesia and using mini submerged arc furnace (SAF) as its technology to reduce manganese ore into ferromanganese metal. Influence of various number of coal as its reductor agent have been ninvestigated. The optimized parameter has been established to obtain maximum yield. The experiments with 30 kg of manganese ore, 12 kg of limestone, and various number of coal ranging from 40.33%, 47%, 53.67%, and 60.33% have been carried out. The efforts have also been made to reduce the electrical consumption and the cost of production by using coal instead of cokes.The result showed that an increase in number of reductor increases the amount of product, manganese content, yield ratio, mass of offgas, energy consumption, phosphorus and sulfur content. Biggest number of ferromanganese which can be produced is 9.1 kg with 72% manganese content inside the metal from 53.67% coal and the smallest manganese content is 63.12%Mn from 40.33% coal. Biggest number of off gasses is 33.5 kg which came from 60.33% coal and this phenomena showed that reduction process is not efficient. Highest energy consumption came from 40.33% coal which is 12.45 kwh/kg FeMn product, and the most efficient energy is produced by 53.67% coal which is 7.56 kwh/kg FeMn product. Biggest phosphorus and sulfur content came from 53.67% coal which is 0.74%P and 0.9%S. As the last result, the most optimum research has been carried out by 47% of coal.]"

"[ABSTRAKPotensi cadangan bijih mangan di Indonesia cukup besar, namun terdapatdi berbagai lokasi yang tersebar di seluruh Indonesia. Komoditi ini menjadi bahanbaku 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 memperbaikisifak-sifat mekanik dari produk yang dihasilkan.Penelitian ini dilakukan untuk mempelajari pengaruh proses pencanpuranbijih 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 berasaldari Jember, Jawa Timur (27,7 %Mn-4,4 %Fe-14,7%Si) sebagai bahan baku untukpembuatan logam FeMn dengan kandungan minimal sebesar 50 %Mn. Penelitianini dilakukan sebanyak 5 kali percobaan dengan variasi pada campuran bijih Mnyaitu [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 ArcFurnace (SAF) dengan input berupa bijih Mn sebagai bahan baku utama, kokassebagai reduktor, dan kapur sebagai aditif. Ketiga bahan baku tersebut dileburhingga mencapai temperatur 1500 oC. Untuk mengetahui kualitas bahan baku danproduk FeMn yang dihasilkan, dilakukan analisa seperti XRF (X-RayFluoroscence), XRD (X-Ray Diffraction), AAS (Atomic Absorbtion Spectrometry),dan Proksimat.Dari hasil penelitian didapatkan bahwa untuk percobaan [1] diperolehlogam FeMn sebanyak 5,2 Kg dengan kadar 54,05 %Mn, percobaan [2] diperolehlogam FeMn sebanyak 4,75 Kg dengan kadar 50,03 %Mn, percobaan [3] diperolehlogam FeMn sebanyak 4,6 Kg dengan kadar 36,44 %Mn, percobaan [4] diperolehlogam 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 dariproses pencampuran (Mn-blend) dalam pembuatan ferromangan ini adalahsemakin banyak komposisi bijih Mn kadar menengah (MG) yang digunakan,menyebabkan (a) semakin banyaknya kokas dan semakin berkurangnya kapur yangdibutuhkan, (b) meningkatnya yield, jumlah produk, serta kandungan persentaseMn dari FeMn yang dihasilkan, dan (c) semakin rendahnya konsumsi energi yangdibutuhkan.ABSTRACTThe potential reserve of manganese ore in Indonesia is very large, but itwas located in different locations spread throughout Indonesia. Manganese ore isone of raw material in producing ferromanganese that is not replaceable in theworld steel industry. Ferromanganese (FeMn) is an alloying metal that containedof 75% Manganese (Mn) and 25% Iron (Fe) which is generally used in the processof iron/steel making to improve its mechanical properties.In this experiment, ferromanganese production was conducted by blendingtwo kinds of manganese ore, that was low grade Mn ore (LG) which derived fromTanggamus, 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), toobtain ferromanganese with a minimum content of 50 %Mn. The composition ofMn-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 manganeseore was processed by using Submerged Arc Furnace (SAF). Cokes and limestonewas added into the furnace as reductant and flux agent, respectively. Those rawmaterials are smelted until 1500 °C. To determine the composition of raw materialsand the product of FeMn, analysis such as XRF (X-Ray Fluorescence), XRD (XRayDiffraction), AAS (Atomic Absorption Spectrometry), and proximate have to bedone.From each composition of Mn-blend above in this experiment, it wasobtained 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 thisferromanganese production was by the increasing composition of the mediumgrade manganese ore (MG) that will cause: (a) the increasing number of cokes andthe decreasing of limestone required, (b) the increasing of yield, the number ofproducts, and also the percentage of manganese content FeMn, and (c) thedecreasing of energy consumption required., The potential reserve of manganese ore in Indonesia is very large, but itwas located in different locations spread throughout Indonesia. Manganese ore isone of raw material in producing ferromanganese that is not replaceable in theworld steel industry. Ferromanganese (FeMn) is an alloying metal that containedof 75% Manganese (Mn) and 25% Iron (Fe) which is generally used in the processof iron/steel making to improve its mechanical properties.In this experiment, ferromanganese production was conducted by blendingtwo kinds of manganese ore, that was low grade Mn ore (LG) which derived fromTanggamus, 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), toobtain ferromanganese with a minimum content of 50 %Mn. The composition ofMn-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 manganeseore was processed by using Submerged Arc Furnace (SAF). Cokes and limestonewas added into the furnace as reductant and flux agent, respectively. Those rawmaterials are smelted until 1500 °C. To determine the composition of raw materialsand the product of FeMn, analysis such as XRF (X-Ray Fluorescence), XRD (XRayDiffraction), AAS (Atomic Absorption Spectrometry), and proximate have to bedone.From each composition of Mn-blend above in this experiment, it wasobtained 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 thisferromanganese production was by the increasing composition of the mediumgrade manganese ore (MG) that will cause: (a) the increasing number of cokes andthe decreasing of limestone required, (b) the increasing of yield, the number ofproducts, and also the percentage of manganese content FeMn, and (c) thedecreasing of energy consumption required.]"

"Mineral mangan merupakan salah satu mineral yang paling banyak ditemui di kerak bumi. Sebagian besar produksi mangan dan paduannya di dunia saat ini diserap oleh industri baja. Ferromangan merupakan salah satu logam paduan dengan kandungan mangan yang sangat tinggi, yaitu sekitar 65 - 90%. Sebanyak 90%, ferromangan digunakan untuk menambahkan unsur mangan kedalam material baja untuk memperbaiki sifat-sifat mekanik dari material baja, seperti kekuatan, hardenability, dan ketahanan terhadap aus. Penelitian ini bertujuan untuk mengetahui pengaruh penambahan kadar kokas terhadap keefisienan proses reduksi bijih mangan lokal kadar menengah menjadi produk ferromangan. Proses reduksi dilakukan pada tungku submerged arc furnace tiga fasa dengan kapasitas 100 Kg/Batch dilengkapi dengan tiga buah elektroda grafit. Setiap percobaan menggunakan 30 Kg bijih mangan lokal, 12 Kg limestone, dan kadar kokas yang bervariasi, yaitu 5,5 Kg (18,33%), 7,5 Kg (25,00%), 9,5 Kg (31,67%), dan 11,5 Kg (38,33%). Hasil penelitian menunjukkan bahwa kuantitas dan kualitas produk ferromangan yang dihasilkan meningkat seiring dengan bertambahnya kadar kokas yang digunakan. Dimana kandungan mangan pada ferromangan dan massa/yield produk ferromangan cenderung meningkat. Kandungan mangan pada produk ferromangan tertinggi sebesar 78% pada pengujian menggunakan kokas sebanyak 7,5 Kg (25,00%). Sedangkan massa produk ferromangan tertinggi terdapat pada pengujian dengan menggunakan kokas sebanyak 9,5 Kg (31,67%), yaitu 12,8 Kg. Dan pada penggunaan energi selama proses berlangsung cenderung menurun dengan penambahan kokas, dimana penggunaan energi terendah selama proses reduksi berlangsung pada pengujian menggunakan kokas sebanyak 9,5 Kg (31,67%) sebesar 7,03 KWh/Kg. Namun konsumsi elektroda cenderung meningkat. Sehingga konsumsi elektroda grafit terendah pada saat menggunakan kokas 5,5 Kg (18,33%), yaitu sebesar 0,75 Kg. Berdasarkan aspek ekonomi, pengujian dengan keuntungan tertinggi terdapat pada pengujian menggunakan kokas sebanyak 9,5 Kg (31,67%) yaitu sebesar Rp 62.565 pada tiap satu kali pengujian.

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Manganese is one of the most common minerals in the earth’s crust.Manganese plays an important role in the development of various steel making processes and its continuing importance is indicated by the fact that about 90% of all manganese alloys consumed annually goes into steel production as an alloying element in the form of ferromanganese. Ferromanganese is one of the metal alloys with a high content of manganese, which is about 65 - 90%. Manganese has four functions to steel such as desulphurizing agent, deoxidation agent, enhancing hardness, and wear resistance. This research, studies have been made to obtain the most optimum raw material composition to produce ferromanganese metal based on local medium grade manganese ore with various amount of cokes as its main variable. The process is conducted four times by smelting manganese ore into ferromanganese metal in mini submerged arc furnace (SAF) technology using three graphite electrodes. The process begin with using 30 kg of medium grade manganese ore from Jember, East Jawa-Indonesia, 12 kg of limestone as its fluxing agent, and various number of cokes from 5,5 kg (18,33%), 7,5 kg (25%), 9,5 kg (31,67%), and 11,5 kg (38,33%). Influence of various amount of cokes being used in this study have been investigated. The experiment conducted by increasing number of cokes carried out good results. Higher consumption of cokes will produce bigger number of ferromanganese metal and also the manganese content inside it. The most optimum composition of cokes shown by this study is 9,5 kg (31,67%), producing the biggest number of product at 12,8 kg of ferromanganese and consuming the least energi at 7,03 kwh/kg FeMn. The other result also showed that adding 7,5 kg (25%) of cokes will produce 78% manganese content inside the metal which was the highest manganese content. However, with an increase of cokes, the electrode consumption will also increase. The experiment with 5,5 kg (18,33%) of cokes carried out the least electrodes consumption at 0,75 kg/process. Moreover, to support the optimum raw material composition, economic evaluation has been conducted. The biggest profit is Rp 62.565,-/process for 9,5 kg (31,67%) of cokes.

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"ABSTRAKMelalui Proses Benefisiasi dengan Variabel Jumlah Penambahan Reduktor Coal dan Aditif CaCO3 pada Reduction-RoastingSekitar 90 dari bijih kromit ditambang dikonversi menjadi ferrochrome oleh industri metalurgi. Industri stainless steel mengkonsumsi sekitar 80 dari ferrochrome yang diproduksi terutama dengan karbon tinggi . Pasir kromit kadar rendah pada penelitian ini merupakan pasir kromit lokal asal Kabupaten Konawe, Sulawesi Selatan. Benefisiasi dilakukan menggunakan teknik Magnetic Separation baik di awal sebelum reduction-roasting maupun di akhir setelah reduction-roasting dan Pre-reduction roasting dilakukan selama 60 menit pada temperatur 1000 C menggunakan variabel penambahan jumlah reduktor sebesar 5 lean coal, stokiometri, 5 excess carbon dan 10 excess carbon serta penambahan jumlah aditif sebesar 5 , 15 , dan 20 . Pengujian XRD dan XRF dilakukan dalam mengarakterisasi sampel awal dan hasil. Rasio Cr/Fe 0,9 dan kadar Cr pada pasir kromit awal 29,3 dalam bentuk Cr2O3 serta kadar Fe 30,9 dalam bentuk Fe2O3. Setelah dilakukan pemisahan magnetik di awal rasio Cr/Fe meningkat menjadi 1,31. Kemudian dilakukan reduksi-roasting dengan hasil bahwa variasi penambahan reduktor dan aditif dapat mempengaruhi perubahan fasa yang terjadi. Dengan seiring penambahan aditif, pemecahan struktur spinel akan semakin baik. Kemudian dilakukan pemisahan magnetic yang dilanjutkan dengan pengujian XRF, rasio Cr/Fe meningkat menjadi 1.530 pada variasi stokiometri reduktor 20 aditif dan 5 excess carbon 20 aditif. Reduktor optimum berada pada stokiometri dan 5 excess carbon sedangkan aditif optimum di 20 . Rasio Cr/Fe setara dengan 60,5 dalam FeCr. Oleh sebab itu, dapat disimpulkan proses benefisiasi berhasil untuk meningkatkan kadar Cr pada pasir kromit kadar rendah. Jenis aditif dan reduktor yang berbeda akan mempengaruhi hasil reduksi-roasting sehingga rasio Cr/Fe yang dihasilkan pun berbeda.Kata kunci: Ferrochrome, pasir krom kadar rendah, pasir krom metallurgical grade, benefisiasi, gravity separation, reduction roasting, magnetic separation

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ABSTRACTThrough Beneficiation Process with the Variation of Reductant Coal and CaCO3 as Additive Dosage on Reduction Roasting Process Approximately 90 of the mined chromite ore is converted to ferrochrome by the metallurgical industry. Chromite sand low grade in this study is a local chromite sand origin Konawe, South Sulawesi. Beneficiation Magnetic Separation is done using techniques well in the beginning before the reduction roasting and in the end after reduction roasting and Pre reduction roasting is done for 60 minutes at a temperature of 1000 C using a variable amount of reductant additions of 5 lean coal, stoichiometric, 5 excess carbon and 10 excess carbon and the addition of an additive at 5 , 15 and 20 . XRD and XRF testing done in characterizing the initial sample and results. The ratio of Cr Fe and Cr content is 0.9 at the beginning of chromite sand in the form of 29.3 Cr2O3 and Fe content of 30.9 in the form of Fe2O3. After magnetic separation at the beginning of the ratio of Cr Fe increased to 1 31. Then do the reduction roasting with the result that the variation of the addition of reductant agents and additives can affect the phase change that occur. With over additive, breaking spinel structure, the better. Then magnetic separation followed by XRF testing, the ratio of Cr Fe increased to 1.530 in the variation of 20 of the stoichiometric reductant additive and 5 20 excess carbon additives. Reductant agents that are in the optimum stoichiometric and 5 excess carbon while the optimum additive at 20 . The ratio of Cr Fe equivalent to 60.5 in FeCr. Therefore, it can be concluded successfully beneficiation process to increase the Cr content at low levels of chromite sand. Type different additives and reductant agents will affect the outcome of reduction roasting so that the ratio of Cr Fe produced any different. "

"ABSTRAKFerokrom (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.

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ABSTRACTFerrochromium (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."