[ABSTRAK
Logam ferromangan adalah salah satu unsur paduan penting pada bajauntuk meningkatkan sifat mekanis, ketahanan aus, dan kekerasannya. Bentukferromangan (FeMn) telah diatur dalam standard ASTM dengan kadar minimalsebesar 75% Mangan (Mn). Tujuan penelitian ini adalah pembuatan logam FeMndengan kandungan minimal 60%Mn dari bijih mangan lokal dan mempelajari efekdari basasitas terak yang dipengaruhi oleh penambahan kapur sebagai zat aditifdalam proses pembuatan ferromangan terhadap jumlah produk ferromangan yangdihasilkan dan konsumsi energi yang dibutuhkan dalam proses tersebut.Dalam penelitian ini digunakan bijih mangan lokal kadar menengah daridaerah 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), 7.5kg kokas, dan jumlah batu kapur yang bervariasi, yaitu; 8, 10, 12, dan 14 kg.Proses peleburan berlangsung pada temperatur 1200-1500 oC. Kemudian hasilakan dianalisa dengan menggunakan XRF (X-Ray Fluoroscence), XRD (X-RayDiffraction), 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 8.2kg FeMn, kemudian memaksimalkan kadar % mangan yang tereduksi pada logamhingga mencapai komposisi kimia yang optimal (78,13 Mn-12,65 Fe-8.93 Si),menekan konsumsi energi hingga 9.8 kwh/kg ferromangan, menekan angkakonsumsi elektroda, dan menghasilkan prosentase efisiensi proses berupa % yieldyang cukup tinggi yakni sebesar 58.61%. Hasil lain yang menunjang prosespengolahan ferromangan dengan meningkatnya hasil basasitas terak adalahtercapainya suhu reaksi yang tinggi yakni sebesar 15940C sehingga membuatreduksi oksida mangan pada terak menjadi mangan pada logam semakin baik,kemudian jumlah terak juga dapat ditekan. Selanjutnya secara tinjauan aspekekonomi dari keempat kali proses penelitian, maka didapatkan hasil yang palingmenguntungkan sebesar Rp 5.731,-/proses.ABSTRACT
Ferromanganese metal is an important alloying element in steel productionindustry used to maximize its mechanical properties such as wear resistance andhardness. The most common form of ferromanganese according to ASTM standardcontain min.75%Mn and max.25%Fe inside the product. The target of this researchis to obtain ferromanganese metal with min.60%Mn using medium grademanganese 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 kindof basicity will determined by the amount of limestone as fluxing agent which addedto the furnace. Moreover, this study will focus to the effect of its slag basicity on thenumber of ferromanganese product and the amoung of energy consumption.This study was taking place at UPT BPM LIPI Lampung, Sumatera. Usingtheir Mini Sub-merged Arc Furnace (SAF) the process began without anybeneficiation processs for its raw material. Manganese ore Ø ±30mm, cokes, andlimestones 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, 7.5kg cokes, and limestones which varied from 8, 10, 12, and 14 kg. Validity of thisstudy supported by the chemical analysis which took place before and afterreduction process using some tools such as XRF (X-Ray Fluoroscence), XRD (XRayDiffraction), AAS (Atomic Absorbtion Spectrometry), and Proxymate analysis.The result of this research showed an increasing trend in product?s qualityas the slag basicity and the amount of limestone increased. As the slag basicityincrease, the number of ferromanganese metal products were also increased until8.2 kg FeMn and the amount of manganese element in metal phase also showed themost optimum chemical composition of ferromanganese metal (78,13 Mn-12,65 Fe-8.93 Si). Furthermore, the energy consumption can be reduced until 9.8kwh/kg FeMn as well as the electrodes consumption and also the efficiencypercentage or % yield process can be increased up to 58.61%. Other parameterswhich used to support these 4-times-research plan was the temperature level whichturned out to be as high as 15940C and helped the reduction process of manganeseoxide into manganese metal became easier. Not only to obtain more manganesecontent in metal phase, but also this level of reduction temperature can reduced theamount of slag. Finally, in addition to support the optimum data, economic analysisalso 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 productionindustry used to maximize its mechanical properties such as wear resistance andhardness. The most common form of ferromanganese according to ASTM standardcontain min.75%Mn and max.25%Fe inside the product. The target of this researchis to obtain ferromanganese metal with min.60%Mn using medium grademanganese 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 kindof basicity will determined by the amount of limestone as fluxing agent which addedto the furnace. Moreover, this study will focus to the effect of its slag basicity on thenumber of ferromanganese product and the amoung of energy consumption.This study was taking place at UPT BPM LIPI Lampung, Sumatera. Usingtheir Mini Sub-merged Arc Furnace (SAF) the process began without anybeneficiation processs for its raw material. Manganese ore Ø ±30mm, cokes, andlimestones 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, 7.5kg cokes, and limestones which varied from 8, 10, 12, and 14 kg. Validity of thisstudy supported by the chemical analysis which took place before and afterreduction process using some tools such as XRF (X-Ray Fluoroscence), XRD (XRayDiffraction), AAS (Atomic Absorbtion Spectrometry), and Proxymate analysis.The result of this research showed an increasing trend in product’s qualityas the slag basicity and the amount of limestone increased. As the slag basicityincrease, the number of ferromanganese metal products were also increased until8.2 kg FeMn and the amount of manganese element in metal phase also showed themost optimum chemical composition of ferromanganese metal (78,13 Mn-12,65 Fe-8.93 Si). Furthermore, the energy consumption can be reduced until 9.8kwh/kg FeMn as well as the electrodes consumption and also the efficiencypercentage or % yield process can be increased up to 58.61%. Other parameterswhich used to support these 4-times-research plan was the temperature level whichturned out to be as high as 15940C and helped the reduction process of manganeseoxide into manganese metal became easier. Not only to obtain more manganesecontent in metal phase, but also this level of reduction temperature can reduced theamount of slag. Finally, in addition to support the optimum data, economic analysisalso showed that this composition was the most profitable process with Rp 5.731,-/process as its profit.]