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"Dalam penelitian ini, dilakukan studi komparatif terhadap tiga material refraktori taphole clay yang berbeda, yaitu produk komersial Duquesne dari Kanada, produk komersial Alusil dari Brazil, dan refraktori taphole clay yang dibuat sendiri dengan bahan penyusun Fire Clay, MgO, dan bahan pengikat minyak tar ( perbandingan 1 : 2 : 1 ). Semua sampel dikeringkan dan juga ada yang dipanaskan sampai dengan temperatur 11000C sebelum dilakukan karakterisasi dengan menggunakan XRD, XRF, PSA, SEM/EDAX, DTA-TGA. Pengujian XRD menunjukan bahwa terjadi transformasi fasa pada ketiga sampel yaitu adanya proses dekomposisi, proses perubahan struktur kristal, dan pembentukan fasa baru.Hasil pengujian XRF menunjukan hasil yang semi-kuantitatif karena fraksi massa hasil pengujian XRF tidak sesuai dengan hasil perhitungan stoikiometri pada hasil XRD. Pengukuran rata-rata besar distribusi partikel pada ketiga sampel menunjukan bahwa ketiga sampel memiliki ukuran partikel yang relatif kecil yaitu dibawah 6 m. Semakin kecil ukuran partikel material refraktori, maka semakin kecil porositas material refraktori tersebut sehingga sehingga akan memiliki ketahanan korosi yang lebih dari serangan logam cair dan terak. Pada pengujian termal dengan DTA-TGA terhadap ketiga sampel, terdapat reaksi endotermik yang menunjukan adanya proses dehydroxylation atau hilangnya air kristal serta teroksidasinya karbon pada material refraktori yang mengandung bahan pengikat minyak tar dan reaksi eksotermik dimana terjadinya pembentukan fasa baru.

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In this research, a comparative study was conducted on three different taphole clay refractories. The taphole clay refractories are Duquesne, commercial product from Canada, Alusil, commercial product from Brazil, and taphole clay refractories made by myself that has composition fire clay, MgO, and tar oil as binder ( with ratio 1 : 2 : 1 ). All the samples were dried and also heat treated up to 11000C prior to characterization by using XRD, XRF, PSA, SEM/EDAX, DTA-TGA. XRD testing showed that the phase transformation occurred in all three samples, i.e. there is decomposition process, changes in the crystal structure, and the formation of a new phase.

XRF testing results showed semi-quantitative result because mass fraction from XRF testing results differ from the results of stoichiometric calculations on the XRD results. The average measurement of the distribution of particles in all three samples showed that all three samples have a relatively small particle size of below 6 m. The smaller the particle size of the refractory material, the smaller the porosity of the refractory material so the material will have a good corrosion resistance against molten metal and slag attack. Thermal testing with DTA-TGA in all three samples showed that there are endhotermic reaction which indicates the dehydroxylation process or loss of crystal water also oxidation of carbon in samples that contain tar oil and exothermic reaction in which the formation of a new phase."

"Cadangan bijih mangan kadar rendah di Indonesia cukup besar, namun cadangan bijih mangan tersebut tidak dapat dimanfaatkan secara optimal karena rendahnya rasio Mn/Fe.Sehingga diperlukan penelitian untuk mempelajari metode benefiasi guna meningkatkan rasio Mn/Fe, menggunakan bijih mangan kadar rendah dari Kabupaten Tanggamus (MnO=15.30%, rasio=0.91) dan kabupaten Jember (MnO=28.66%, rasio=1.39) supaya bisa dijadikan bahan baku dalam pembuatan FeMn menggunakan SAF.Penelitian benefisiasi bijih mangan kadar rendah dimulai dengan melakukan fraksinasi untuk mendapatkan ukuran butir 841-420 μm, 420-250 μm dan 250-177 μm kemudian dilakukan proses pemisahan gravitasi untuk menghasilkan concentrate dan tailing yang akan digunakan sebagai bahan baku untuk reduction reduction roasting. Proses reduction roasting dilakukan dengan variasti suhu 500°C, 700°C dan 900°C serta variasi waktu reduction roasting 30, 60, 90 dan 120 menit dan kemudian dilakukan proses pemisahan secara magnetic. Material non magnetik yang menghasilkan peningkatan rasio Mn/Fe paling optimum akan dilakukan proses briketisasi untuk digunakan sebagai bahan baku pembuatan FeMn menggunakan SAF.Pengaruh variasi temperatur dan waktu reduction roasting memberikan hasil rasio Mn/Fe optimum 6.11, pada partikel non magnetik ukuran 841-420 μm dengan suhu reduction roasting 700°C selama 60 menit. Proses reduction roasting juga menyebabkan munculnya fase baru seperti Hausmanite (Mn3O4), Manganosite (MnO), Fayalite (Fe2SiO4) dan Phlogopite (KMg3(AlSi3O10(OH)2), akibat proses perubahan fase pada bijih mangan. Fase mineral tersebut muncul pada reduction roasting variasi waktu 60 menit, 90 menit dan 120 menit, serta muncul pada variasi suhu 500°C, 700°C dan 900°C.Pada pengujian dalam SAF digunakan basisitas berdasarkan stoichiometri dengan nilai 1.17, 1.32, 1.15 dan basisitas referensi hasil penelitian Bobby et al, 2015, dengan nilai 0.7. Penggunaan basisitas 0.7 menghasilkan kenaikan berat metal dan menurunkan berat terak pada saat diproses dalam SAF. Selain itu basisitas stoichiometry hanya menghasilkan ferromangan dengan Mn=35.47% dan basisitas referensi 0.7 menghasilkan Ferromangan dengan Mn=60%.Hasil penelitian ini menunjukkan bahwa peningkatan rasio menggunakan benefisiasi bisa mencapai rasio 6.11. Sedangkan proses pembuatan FeMn dengan menggunakan bijih mangan kadar rendah pada submerged arc furnace bisa menghasilkan kadar Mn 60% dengan kontrol pada basisitas untuk mengurangi volume terak, meningkatkan berat logam dan menaikkan kadar Mn.

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Low grade manganese ore reserves in Indonesia is quite large, but manganese ore reserves can not be used optimally because of the low ratio of Mn / Fe.In that case, research is needed to study the methods of benefiasiation to increase the ratio of Mn / Fe, using low grade manganese ore from Tanggamus ( MnO = 15.30% ratio = 0.91) and Jember (MnO = 28.66%, ratio = 1.39) that can be used as raw material in the manufacture of FeMn using SAF.

Research for beneficiation of low grade manganese ore started by fractionation to obtain the grain size of 841-420 μm, 420-250 μm dan 250-177 μm then performed meja getar process to produce the concentrate and tailings to be used as ingredients raw for reduction roasting. Reduction roasting variety process carried out with a temperatur of 500 °C, 700 °C and 900 °C and roasting time variation of 30, 60, 90 and 120 minutes and then a magnetic separation process. Non-magnetic material that produces an increase in the most optimum ratio of Mn/Fe will be used into bricketing process as raw material for FeMn using SAF.

The effect of variation of temperatur and roasting time results ratio of Mn/Fe optimum 6.11, on a non-magnetic particle size of 841-420 μm with a roasting temperature of 700 °C for 60 minutes. Roasting also cause new phase occurensces such as Hausmanite (Mn3O4), Manganosite (MnO), Fayalite (Fe2SiO4) and Phlogopite (KMg3(AlSi3O10(OH)2), due to the process of phase changes in manganese ore. Mineral mineral appeared on roasting with time variations 60 minutes, 90 minutes and 120 minutes, as well as appearing on the variation in temperatur of 500 °C, 700 °C and 900 °C.

On testing in the SAF used basicity based stoichiometri with a value of 1.17, 1.32, 1.15 and reference basicity 0.7 based on the Bobby et al, 2015 reserach. Influence of basicity resulted in an increase of weight of metal and decrease the weight of slag during processing in the SAF. In addition basicity stoichiometry produces only ferromangan with Mn = 35.47% and reference basicity 0.7 generate Ferromangan with Mn = 60%.

The results of this study showed that increasing the ratio of Mn/Fe using beneficiation could reach a ratio 6.11. While the process of making FeMn using low grade manganese ore at Submerged arc furnace can produce 60% Mn grade with controls on basicity to reduce the volume of slag, improve and raise the level of heavy metals Mn."

"[ABSTRAKLogam 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.ABSTRACTFerromanganese 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.]"

"[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.]"

"Phase trnasformation temperature of shape memory alloy - Tini produced by arc - melting technique. The observation of phase trnasformation temperature of Tini alloys produced by arc - melting technique was carried out by alloying Ti - 53%w Ni. Tini alloys were tempered at 900oC and then followed by quenching at 20oC and 5oC and finally were aged at 400oC for 1,4 and 16 hours. The Ti-53%. Ni alloyed is applied to obtain as shape memory alloys base on Tini . The Tini sample was analyzed by optical microscope, X - ray diffraction and simultaneous symmetrical thermoanalyzer (STA) . The result show that the martensitic phase has a structure of BCT (bODY CENTER TETRAGONAL) formed at room temperarure. The phase transformation temperature from martensitic - austensitic phase was taken place at (162+5)oC"

"Polymer Elektrolit Membrane Fuel Cell (PEMFC) merupakan salah satu fuel cell yang berkembang yang mampu menghasilkan energi yang efisien dan sangat potensial untuk digunakan pada alat transportasi, komponen portable seperti laptop serta stasiun penghasil panas dan energi. Bagian penting pada fuel cell jenis ini adalah bipolar plate yang merupakan komponen penyuplai berat dan volume mencapai 80% dari berat fuel cell secara keseluruhan. Sehingga perlu direkayasa dengan material composite ringan namun memiliki sifat mekanis dan konduktivitas yang baik. Penelitian-penelitian mengenai karbon composite mampu menghasilkan nilai konduktivitas tinggi. Penambahan reinforcement MnO2 dengan komposisi 0% - 20% pada carbon composite bipolar plate dengan bahan utama limbah grafit Electric Arc Furnace, grafit sintetis, carbon black serta epoxy yang dicampur dan dilakukan hot press sebesar 300 kg/cm2 pada T=70_C selama 4 jam menghasilkan kekuatan flexure optimal 33,4 MPa, konduktivitas 0,35 S/cm, densitas 2,07 gr/cm3, serta porositas 2,04%. Hasil tersebut membuktikan MnO2 dapat meningkatkan kekuatan tekan hingga lebih 2 kali lipat, meski konduktivitasnya menurun drastis.

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Polymer Electrolyte Membrane Fuel Cell (PEMFC) is famous Fuel Cell which can produce effective and potential energy for used on transportation vehicle, portable computer, and thermal and energy stationary. The important component of fuel cell system was bipolar plat. Nowadays bipolar plate is the highest volume and weigh supplied component on 80% from all weight fuel cell. So must be fabricated with the light composite material but have high mechanical properties and conductivity. The experiment about carbon composite have highest conductivity.

Addition MnO2 reinforcement with the composition 0% - 20% on carbon composite bipolar plate with Electric Arc Furnace Graphite as main material, synthetic graphite, carbon black and epoxy which is mixed and hot pressed on 300 kg/cm2, 70_C in temperature, for 4 hour have optimal flexure strength 33,4 MPa, conductivity 0,35 S/cm, density 2,07 gr/cm3, and porosity 2,04%. That result show that MnO2 would be increase mechanical properties up to 2 times, although drastic decreasing in conductivity."

"Electric Arc Furnace (EAF) merupakan beban nonlinier yang bervariasi seiring waktu, sehingga dapat menyebabkan masalah pada kualitas sistem tenaga listrik, seperti overvoltage dan undervoltage. Salah satu cara untuk menjaga kestabilan tegangan adalah mengompensasi daya reaktif karena daya reaktif yang dikirimkan ke suatu sistem tenaga listrik akan memengaruhi tegangan di sisi penerima. Static Var Compensator (SVC) adalah salah satu kompensator daya reaktif yang akan memberikan atau menyerap daya reaktif, sehingga mempengaruhi tegangan dan faktor daya sistem. Untuk mengetahui pengaruh penggunaan SVC, evaluasi dilakukan dengan load flow analysis di Bus yang terhubung dengan masukan transformator electric arc furnace, yaitu Bus 9 dan 10. Berdasarkan simulasi, SVC sebesar 210 MVAR pada Bus 9 dan 25 MVAR pada Bus 10 dapat meningkatkan persentase kedua Bus, yaitu Bus 9 dari 96.605% menjadi 98.348% dan Bus 10 dari 94.166% menjadi 96.97%. Selain itu, SVC juga meningkatkan nilai faktor daya kedua Bus, yaitu Bus 9 dari 0.744 menjadi 0.952 dan Bus 10 dari 0.851 menjadi 0.952.

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The Electric Arc Furnace (EAF) is a nonlinear load that varies over time, which can cause problems with the quality of the power system, such as overvoltage and undervoltage. One way to maintain voltage stability is by compensating for reactive power because the reactive power supplied to a power system will affect the voltage at the receiving end. The Static Var Compensator (SVC) is one of the reactive power compensators that will provide or absorb reactive power, thereby affecting the voltage and power factor of the system. To determine the effect of SVC usage, an evaluation is conducted using load flow analysis at the Bus connected to the input of the electric arc furnace transformer, which is Bus 9 and 10. Based on the simulation, an SVC of 210 MVAR at Bus 9 and 25 MVAR at Bus 10 can increase the percentages of both buses, with Bus 9 increasing from 96.605% to 98.348% and Bus 10 increasing from 94.166% to 96.97%. Additionally, the SVC also increases the power factor values of both buses, with Bus 9 increasing from 0.744 to 0.952 and Bus 10 increasing from 0.851 to 0.952."

"Penelitian yang akan dikembangkan adalah material pelat bipolar polimer komposit berbasis karbon, terdiri dari epoksi resin dan hardener sebagai binder, sedangkan grafit, carbon black (CB) dan tabung nano berdinding banyak (multiwall carbon nanotube-MWCNT) sebagai penguat (reinforcement) dan pengisi (filler). Berbagai komposisi material serta variasi proses kompresi dilakukan untuk mendapatkan optimasi pelat bipolar yang memenuhi persyaratan, oleh karena itu penelitian ini dilakukan dalam beberapa tahapan. Pada tahapan awal penelitian, bertujuan untuk mengetahui apakah grafit limbah elektroda electric arc furnace (grafit EAF) dapat digunakan untuk menggantikan grafit sintetis sebagai reinforcement material dalam polimer karbon komposit. Pelat bipolar berbasis grafit EAF yang berukuran partikel < 44 µm dan pelat bipolar berbasis grafit sintetis berukuran partikel < 55 µm dicampur dengan carbon black (CB) pada interval komposisi dari (0; 2.5; 5; 7.5; 10; 12.5; 15; 17.5 dan 20) wt%. Proses kompresi dilakukan pada tekanan 30 MPa dan temperatur 70 0C. Sifat pelat bipolar dengan penguat (reinforcement) yang berasal dari grafit sintetis atau grafit EAF menunjukkan hasil yang relatif sama untuk ke empat jenis pengujian yaitu pengujian densitas, porositas, kekuatan fleksural dan konduktivitas listrik pada penambahan CB (5 dan 10) wt%. Hasil pengujian dengan penambahan polimer konduktif polianilin (PANI) pada rentang konsentrasi dari (0.027; 0.054; 0.081 dan 0.108) %wt memberikan konfirmasi dan justifikasi bahwa grafit EAF dapat digunakan sebagai reinforcement untuk menggantikan grafit sintetis. Penelitian pada tahapan lanjut hanya menggunakan grafit EAF dan CB yang berasal dari serabut kelapa hasil proses pirolisis pada temperatur 600 0C dalam lingkungan nitrogen. Variabel penelitian mencakup variasi tekanan dan temperatur kompresi, variasi ukuran partikel baik untuk grafit maupun CB. Kekuatan fleksural optimum dicapai pada tekanan kompresi 55 MPa dan temperatur kompresi 100 0C sebesar (48 ? 48.24) MPa, telah memenuhi persyaratan pelat bipolar DOE yaitu > 25 MPa. Nilai densitas seluruh hasil pengujian (1.69 ? 1.78) gr/cm3lebih kecil dari 5 gr/cm3, hal ini juga telah memenuhi persyaratan sebuah pelat bipolar yang ringan. Hasil pengujian untuk porositas berkisar antara (0.36-0.70) %. Pelat bipolar dengan komposisi CB 5 wt%, temperatur kompresi pada 100 0C serta tekanan kompresi pada 55 MPa memberikan hasil yang relatif lebih baik dibandingkan dengan komposisi CB 10 wt%. Penambahan MWCNT bertujuan untuk meningkatkan sifat mekanik dan listrik pada pelat bipolar yang dihasilkan dari penelitian sebelumnya. Nilai densitas terendah dan kekuatan fleksural tertinggi dihasilkan pada komposisi 90grafit EAF/5CB/5MWCNT yaitu sebesar 1.52 gr/cm3 untuk densitas dan 63.71 MPa untuk kekuatan fleksural. Nilai konduktivitas tertinggi dari seluruh tahapan penelitian diperoleh dari pelat bipolar dengan komposisi 95grafit EAF/2CB/3MWCNT yaitu sebesar 8.94 S/cm.

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This research will examine the utilization of an alternative material to obtain bipolar plates that are light, affordable, and can be mass produced. The research that will be developed is to create carbon-based composite bipolar plate material consisting of epoxy resin and hardener as a binder, graphite, carbon black (CB) and multiwall carbon nano-tube (MWCNT) as a reinforcement or filler material. Various material compositions and variations made to get the compression molding process optimization of bipolar plates that meet requirements that can be obtained by several stages. We investigated whether graphite electrode waste from electric arc furnace (EAF) can subtitute graphite synthetic as a reinforcement material for polymer carbon composite. Bipolar plate based on graphite EAF has particle size < 44 micron, and bipolar plate based on graphite synthetic with particle size of < 55 micron mixing with carbon black (CB) from 0-20% w/w at intervals of 2.5% w/w. The materials are molded using compression hot press machine (30 MPa, 70oC). Samples are tested for: density, porosity, flexural, and electric conductivity, indicated the bipolar plate characteristics with graphite synthetic or graphite EAF showed the same results relatively. Further research showed that the characteristics of synthetic graphite-based bipolar plates and graphite EAF were influenced by the addition of conductive polymers such as polyaniline at interval concentration from 0,027 w/w; 0,054w/w; 0,081 w/w and 0,108 w/w. These results provide confirmation and justification that graphite is used subsequently derived from EAF graphite as reinforcement and the CB additions at (5 and 10) w/w used as a filler material bipolar plates. We then used graphite EAF and CB resulting from pyrolysis process of coconut husk at 600 0C for 10 hours in nitrogen environment. Research variable covered of variety of pressure and temperature compression, variety of particle sizes of graphite EAF or CB. Flexural strength was recorded to be optimum at 48.24 MPa (at 45 MPa, 100 0C), which fulfilled the requirement of bipolar plate > 25 MPa. Density test for all EAF graphite based bipolar plates less than 5 g/cm3. In addition, the porosity for all samples were under 2% (0.36 %-1.92%). Properties of bipolar plates with CB 5 w/w (at 55 MPa, 100 0C and pyrolysis temperature at 900 0C) showed relatively better results compared with CB 10 w/w. The effect of MWCNT improved mechanical and electrical properties. The lowest density value and the highest flexural strength achieved at composition of 90graphite EAF/5CB/5MWCNT of 1.53 g/cm3 for density and 63.71 MPa for flexural strength. The highest conductiviy value from of all research stages achieved from composition of 95graphite EAF/2CB/3MWCNT of 8.94 S.cm-1."

"Electric Arc Furnace Dust (EAFD) sebagai limbah dari pengolahan besi baja terkontaminasi oleh zat radioaktif Cs-137 secara tidak disengaja karena ketidakmampuan fasilitas pengolah melakukan deteksi terhadap keberadaanya. Masalah penelitian ini adalah pengelolaan EAFD sebagai material terkontaminasi radioaktif belum dinyatakan dapat dilakukan dengan aman dan selamat. Dalam penelitian ini dilakukan serangkaian analisis meliputi perhitungan konsentrasi aktivitas radionuklida, penetapan tingkat klierens, penerimaan masyarakat terhadap pengolahan material terkontaminasi radioaktif, keselamatan radiasi dan lingkungan serta nilai ekonomi dari pemanfaatan EAFD. Tujuan akhir dari penelitian ini adalah kegiatan pemanfaatan material tekontaminasi radioaktif dapat dilaksanakan secara berkelanjutan berdasarkan parameter keselamatan radiasi dan lingkungan, penerimaan masyarakat dan nilai ekonomi. Metode analisis penelitian menggunakan statistik deskriptif dan Structural Equation Modeling – Partial Least Square (SEM-PLS). Hasil riset ini adalah konsentrasi aktivitas radionuklida dari Cs-137 pada Paving Block berada dibawah tingkat klierens dan telah mendapatkan persetujuan badan pengawas untuk dapat mengelola EAFD terkontaminasi radioaktif. Penerimaan masyarakat dipengaruhi signifikan oleh manfaat yang dirasakan (perceived benefit) sebesar 63,1% dan risiko yang dirasakan (perceived risk) sebesar 0,16%. Produk Paving Block melewati nilai baku mutu TCLP A dan TCLP B untuk unsur Barium (Ba) yaitu sebesar 8,66 mg/L. Untuk unsur Chromium Hexavalent (Cr6+) berada pada level TCLP B yaitu sebesar 0,15 mg/L. Hasil uji kuat tekan menunjukan paving block tidak memenuhi uji kuat tekan sesuai semua mutu SNI 03-0691-1996 yaitu sebesar 7,36 Mpa (campuran 20% EAFD), 8,3 Mpa (campuran 25% EAFD) dan 7,19 Mpa (campuran 30% EAFD). Pemodelan Resrad Onsite 7.2 menunjukan nilai batas dosis sebesar 1 mSv/tahun bagi masyarakat tidak terlampaui untuk skema jalur pajanan radiasi eksternal, inhalasi dan soil ingestion. Nilai ekonomi dari pemanfaatan EAFD dalam pembuatan paving block tidak signifikan menurunkan harga produksi yaitu Rp. 2.213,77 per buah atau Rp. 97.405 per meter persegi. Mekanisme klierens mampu menghemat biaya pengelolaan material terkontaminasi radioaktif yaitu Rp. 572.137.153 jika dikelola sebagai limbah radioaktif.

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Electric Arc Furnace Dust (EAFD) as waste from steel processing is unintentionally contaminated with radioactive substance Cs-137 due to the inability of the processing facility to detect its presence. The problem of this research is that the management of EAFD as radioactive contaminated material has not yet been declared can be done safely. In the study, a series of analyses were carried out including the calculation of the concentration of radionuclide activity, the determination of clearance levels, public acceptance of the processing of radioactive contaminated materials, radiation and environmental safety and the economic value of the use of EAFD. The ultimate objective of this study is that the activities of the utilization of radioactive contaminated materials can be carried out sustainably based on radiation safety and environmental parameters, public acceptance and economic value. Methods of research analysis using statistical descriptives and Structural Equation Modeling – Partial Least Square (SEM-PLS). The result of this research is that the concentration of radionuclide activity of Cs-137 on the paving block is below the clearance level and has obtained regulatory approval to be able to manage radioactive contaminated EAFDs. Perceived benefits accounted for 63,1% and perceived risks for 0,16%. The paving block product passes the TCLP A and B quality standards for the barium (Ba) element, which is 8,66 mg/L. For the element Chromium Hexavalent (Cr6+) is at the level of TCLP B which is 0,15 mg/L. The pressure test results showed that the paving block did not meet the pressure test according to all SNI quality 03-0691-1996 which is of 7,36 Mpa (mixture 20% EAFD), 8,3 Mpa (25%) and 7,19 Mpa (30%) EAFD. The modeling of Resrad Onsite 7.2 shows the dose limit value of 1 mSv/year for the population not to be exceeded for external radiation exposition pathway schemes, inhalation and soil ingestion. The economic value of the use of EAFD in paving block production does not significantly lower the price of production, which is Rp. 2.213,77 per fruit or Rp. 97.405 per square meter. The cleerens mechanism can save the cost of managing radioactive contaminated material, which is Rp. 572.137.153 if managed as radioactive waste.."