Hasil Pencarian  ::  Simpan CSV :: Kembali

"ABSTRAKSekitar 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.

---

ABSTRACTAround 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."

"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

---

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. "

"ABSTRAKPelindian mangan dari bijih mangan kadar rendah telah berhasil dilakukan menggunakan larutan sulfat. Pada percobaan ini, bijih mangan dipanggang dengan arang kayu sebagi reduktor pada 700 oC selama 120 menit. Kemudian kalsin hasil pemanggangan dilindi menggunakan larutan asam sulfat. Parameter proses pelindian yang diamati meliputi pengaruh kecepatan pengadukan, konsentrasi asam, temperatur, waktu dan persen padatan terhadap mangan terekstrak. Hasil optimum didapat pada proses pelindian dengan konsentrasi 12% H2SO4, kecepatan pengadukan 400 rpm, rasio padatan 1:10, dan temperatur 75 oC selama 3 jam dengan mangan terekstrak sebesar 84,61%. Kinetika reaksi pelindian mangan dalam asam sulfat dikendalikan oleh proses difusi dengan nilai energi aktivasi sebesar 4,88 KJ/mol.

---

ABSTRACT

The leaching of manganese from low-grade manganese ores in aqueous sulfuric acid solution was investigated. In this study, manganese ores were prepared by reduction roasting using charcoal as a reductant at 700 oC for 120 min. The roasted samples were then leached with aqueous sulfuric acid solution. The effects of agitation rate, sulfuric acid concentration, solid/liquid mass ratio, leaching temperature and leaching time on the leaching efficiency of manganese were studied. The optimal leaching conditions are achieved at 12% H2SO4, agitation rate of 400 rpm, solid/liquid mass ratio of 1:10, and the leaching temperature of 75 oC for 180 min. Under the optimal condition, the leaching efficiency of manganese can reach 84.61%. The kinetical reaction of manganese dissolution in aqueous sulfuric acid solution was found to be controlled by diffusion process with activation energy is 4.88 KJ/mol."

"ABSTRACTThere has been a constant need in developing new ways of extracting valuable elements from its ore from time to time. There is always an effort made by scientists and engineers all around the globe in the pursuit of extraction methods that is more efficient and beneficial than ever before. Rice husk is the byproduct of rice production. It is estimated that nowadays the utilization of this byproduct is not maximized yet, while the rice production in Indonesia itself keeps on increasing. This research was intended to study the utilization of rice husk as the reduction agent of lateritic nickel ore. The reduction process done have been able to reduce the limonite ore to NiO and magnetite. The beneficiation process that was done in this research includes roasting ndash quenching and reduction process. The best result of the Fe and Ni concentration of the final product was 19.81 wt. and 1.23 wt. respectively. The nickel beneficiation have been succeeded having increased the initial nickel content in the limonite ore of 1.19 wt. to 1.23 wt. in the final product. The beneficiation process that was done in this research includes roasting ndash quenching and reduction process.

---

ABSTRAKKebutuhan untuk mengembangkan cara ndash; cara baru untuk proses ekstraksi elemen berharga dari sumbernya terus menerus meningkat dari waktu ke waktu. Para peneliti selalu berusaha untuk mengembangkan cara ekstraksi yang lebih efisien dan bermanfaat dari yang sebelumnya. Sekam merupakan hasil sambilan dari proses produksi beras. Diperkirakan pada masa ini, pemanfaatan sekam belum maksimal sebanding dengan penghasilannya yang terus meningkat di Indonesia. Riset ini ditujukan untuk mempelajari penggunaan sekam dalam proses benefikasi bijih limonit. Proses benefisiasi yang dilakukan dalam riset ini meliputi proses roasting ndash; quenching dan reduksi. Proses reduksi yang dilakukan telah berhasil mereduksi limonit menjadi NiO dan magnetit. Hasil konsentrasi Fe dan Ni terbaik adalah 19.81 dan 1.23 berturut ndash; turut. Proses benefisiasi nikel telah berhasil dengan meningkatkan konsentrasi nikel dari 1.19 menjadi 1.23."

"[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.

---

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.

"