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"Pemanfaatan aplikasi dengan katalisis menggunakan nanopartikel merupakan salah satu hal yang banyak dilakukan dalam bidang nanosains. Struktur nanopartikel terus dikembangkan untuk meningkatkan kinerja dalam berbagai aplikasi. TiO₂sebagai katalis dilakukan dengan pembentukan TiO₂nanopartikel. Metode molten saltmerupakan salah satu metode yang dapat digunakan untuk mensintesis TiO₂nanowiresdengan menumbuhkan kristal tunggal dalam jumlah banyak melalui media lelehan garam. Pada penelitian ini dilakukan sintesis TiO₂nanowiresmelalui metode molten saltserta modifikasi penambahan logam perak melalui metode presipitasi, impregnasi, dan molten saltsehingga mempengaruhi sifat katalitiknya. Pencampuran dilakukan pada TiO₂anatase, NaCl, dan Na₂HPO₄yang dikalsinasi pada suhu 825°C selama 8 jam dan kemudian didinginkan hingga suhu ruang. Modifikasi penambahan logam perak dilakukan pada metode molten saltdengan perlakuan yang sama. Modifikasi juga dilakukan pada metode presipitasi dengan penambahan larutan NaOH serta pada metode impregnasi dengan perlakuan kalsinasi pada suhu 400°C. TiO₂nanowires dan Ag₂O/ TiO₂ yang telah disintesis dikarakterisasi dengan menggunakan XRD, FTIR, SEM, TEM, UV-Vis DRS, dan amonia TPD. Dengan adanya penambahan logam perak dapat mempengaruhi penurunan nilai energi celah pita namun tidak mempengaruhi struktur morfologinya. Masing-masing katalis yang telah disintesis digunakan dalam reaksi reduksi 4-nitrophenoldengan bantuan NaBH₄. Reduksi 4-nitrophenoldapat ditandai dengan adanya perubahan warna karena adanya katalis yang digunakan dapat mempercepat proses reduksi tersebut. Kecepatan reaksi tertinggi terjadi pada reduksi 4-nitrophenol dengan katalis Ag₂O/TiO₂nanowiresmelalui metode impregnasi dengan waktu reaksi 30 detik. Uji reusabilitas dilakukan terhadap katalis Ag₂O/TiO₂nanowires impregnasi sebanyak 4 kali dan menghasilkan penurunan kecepatan reaksi sebesar 180 kali.

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Utilizing the application with catalysis using nanoparticle is one of many substances conducted in the field of nanoscience. To form TiO₂as a catalyst is by forming TiO₂ nanoparticle. The structure of nanoparticle is keep on being developed to increase its productivity on various applications. The molten salt method is one of the methods that can be used to synthesize TiO2 nanowires by growing up a tremendous amount of single crystals with the medium of molten salt. In this research, there will be conducted the synthesis of TiO₂nanowires using molten salt method with modification by adding silver nitrate metals with precipitation method, impregnation method, and molten salt method so that it will influence its catalytic nature. The mixing is carried out on TiO₂anatase, NaCl, and Na₂HPO₄that are calcined at 825 degrees celsius for 8 hours and then chilled until room temperature is reached. The modification by adding molten salt is carried out on molten salt method with the same treatment. The modification is also carried out on precipitation method by adding NaOH solution, also on impregnation method with calcination at 400 degrees celsius. TiO₂nanowires and Ag₂O/ TiO₂that has been synthesized is characterized by using XRD, FTIR, SEM, TEM, and also UV-Vis DRS. Adding silver metal can influence its band gap devaluation but can not influence its morphological structure. Each synthesized catalysts are being used in the reaction of the reduction of 4-nitrophenol with the help of NaBH₄. The 4-nitrophenol reduction can be marked by the change of color because of the catalysts existence can accelerate the reduction process. The reaction’s highest speed occurs at the reduction of 4-nitrophenol with the catalyst of Ag₂O/TiO₂nanowires with impregnation method with the reaction speed of 30 seconds. The reusability test is conducted to the catalyst of Ag₂O/TiO₂nanowires impregnation for 4 times and resulted in the decrease of reaction speed by 180 times."

"Pemanfaatan mineral ilmenit PT.TIMAH Bangka yang banyak mengandung unsur Ti menjadi sangat penting karena dapat menghasilkan larutan precursor TiOSO4 sebagai bahan baku pembuatan TiO2. Penelitian ini bertujuan untuk mengetahui pengaruh konsentrasi larutan H2SO4 dan temperatur serta mencari model persamaan kinetika yang sesuai pada proses pelindian ilmenit hasil dekomposisi (Potassium Titanat) ini. Bahan baku pelindian yang digunakan adalah serbuk padatan potassium titanat yang merupakan hasil dekomposisi ilmenit. Pelindian dilakukan selama 5 jam dengan pengambilan sampel larutan setiap 30 menit untuk diteliti persentase ekstraksi Ti dan Fe yang terlarut dalam TiOSO4 dan FeSO4. Persentase ekstraksi Ti tertinggi diperoleh dengan besar 85,03% pada pelindian dengan larutan H2SO4 75% pada temperatur 1250C dengan waktu pelindian selama 180 menit. Persentase ekstraksi Fe yang diperoleh pada kondisi yang sama adalah sebesar 31,45%. Adapun persamaan model kinetika yang sesuai untuk proses pelindian tersebut ada 2 macam yaitu model Ginstling-Brounshtein dan model Dickinson. Energi aktivasi terkecil yang diperoleh untuk proses pelindian tersebut dihasilkan dengan menggunakan permodelan Ginstling-Brounshtein dengan nilai masing- masing 29,1 kJ/mol, 54,0 kJ/mol, 52,6 kJ/mol 50,5 kJ/mol untuk pelindian Ti dengan larutan H2SO4 50%, 75%, serta pelindian Fe dengan larutan H2SO4 50%, dan 75%.

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Utilization of ilmenite mineral PT.TIMAH Bangka which contains element of Ti is very important because it can produce TiOSO4 precursor solution as raw material for producing TiO2. This research aimed to determine the effect of H2SO4 concentration and temperature as well as the search for a suitable kinetic equation model to the ilmenite decomposition (Potassium Titanate) leaching process. The leaching raw material is solid potassium titanate powder which is the result of decomposition. The Leaching process took place for 5 hours with solution sampling (extraction) every 30 minutes to study the percentage of Ti and Fe that were dissolved in TiOSO4 and FeSO4 solution. The highest percentage of Ti extraction obtained by the leaching process was 85.03% in 75% H2SO4 solution at 1250C for 180 minutes. The percentage extraction of Fe were obtained at the same conditions was 31,45%. The suitable kinetic equation models for the leaching are Ginstling-Brounshtein model and Dickinson model.

The smallest activation energy for the leaching process was obtained by using Ginstling-Brounshtein kinetic equation model with 29,1 kJ / mole, 54,0 kJ / mole, 52,6 kJ / mole, 50,5 kJ / mole for Ti leaching with a solution of 50% H2SO4, 75% H2SO4, and Fe leaching with a solution of 50% H2SO4 and 75% H2SO4."

"Pada penelitian ini, campuran senyawa LiOH, Al2O3, dan SiO2 telah berhasil dipreparasi melalui dua tahapan proses, yaitu pencampuran selama dua puluh jam dan pembakaran pada temperatur 12000C. Kemudian campuran tersebut diekstraksi melalui proses pelindian menggunakan larutan KOH dan dilanjutkan dengan proses pengendapan menggunakan larutan hangat Na2CO3 dan aliran gas CO2. Pada proses pelindian didapatkan larutan LiOH dimana recovery Li yang didapatkan berbanding lurus dengan variabel temperatur yang digunakan. Hasil optimum proses pelindian didapatkan pada variabel temperatur 2000C dengan nilai recovery Li sebesar 7.13%. Telah dibuktikan pula bahwa pada proses pengendapan recovery Li didalam endapan meningkat seiring dengan meningkatnya rasio Na : Li yang digunakan.

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In this work, the mixture of LiOH , Al2O3, and SiO2 was succesfully prepared by two step, that is mixing about twenty hour and roasting at temperature 12000C. Afterwards, the mixture was extracted by leaching process using KOH solution and then continued by precipitation process using Na2CO3 warm solution and CO2 stream. In the process of leaching, LiOH solution was obtained where recovery of Li which obtained equal with variable of leaching temperature. The optimum yield of leaching process was obtained at temperature 2000C with % recovery 7,13%. It was also proven that’s on precipitation process, Li recovery in precipitate increase as well as increasing of Na : Li ratio."

"Malasit merupakan salah satu bijih sekunder tembaga yang memiliki rumus kimia CuCO3.Cu(OH)2., Bijih malasit termasuk dalam batuan karbonat dan biasanya berwarna biru dan hijau. Pelindian merupakan proses pengambilan logam berharga secara selektif dari bijih dengan pelarut sehingga didapatkan suatu larutan kaya. Pelindian juga bertujuan menaikan kadar dari bijih. Laju proses pelindian dipengaruhi oleh beberapa faktor diantaranya yaitu ukuran partikel, konsentrasi, temperatur dan waktu pelindian. Bahasan penelitian ini ialah pengaruh proses klasifikasi air terhadap kenaikan persentase kadar tembaga dan pengaruh konsentrasi pelarut terhadap persentase peningkatan kadar tembaga pada bijih malasit. Penelitian ini melakukan beberapa pengujian yaitu uji karakterisasi bijih malasit menggunakan EDX dan AAS, uji anilsis filtrat hasil pelindian menggunakan AAS. Hasil dari peneltian ini, penambahan metode proses klasifikasi air menaikkan persetase kadar tembaga dan pengaruh konsentrasi pelarut pada proses pelindian yang berpengaruh terhadap persentase peningkatan tembaga pada bijih malasit.

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Malachite is a secondary ore of copper which has chemical formula CuCO3.Cu (OH)2. Malachite ore included in carbonate rocks and usually colored blue and green. Leaching is the process of making precious metals from ore by selective leaching agents until get a rich solution. Leaching is also increasing the content of ores. The rate of leaching process is influenced by several factors including the particle size, concentration, temperature and time leaching.

Discussion of this study is the influence of the classification process water to increase the percentage of copper content and the influence of the lixiviant concentration to the percentage recovery of copper in malachite ores. Some of the testing performed in this study are malachite ore characterization testing using EDX and AAS, analysis filtrate testing which is the result of leaching, using AAS.

The result of this study is the addition method of water classification process (float sink) can increase the copper content and the influence of lixiviant concentration in the leaching process which can increase the percentage recovery of copper in malachite ores."

"[ABSTRAKLogam tantalum dan niobium merupakan logam yang sumbernya termasuk ke dalam kategori critical in mid term. Terak timah merupakan limbah yang dapat dijadikan sebagai sumber cadangan kedua. Dalam penelitian ini akan dilihat pengaruh pemanggangan pada 700 oC serta pengaruh variasi konsentrasi larutan NaOH dan HCl sebagai larutan lindi, sampel terak timah yang digunakan berasal dari Indonesia dengan kadar 0,33% Ta2O5 dan 0,64% Nb2O5. Pengujian XRF digunakan untuk melihat perubahan kadar Ta2O5 dan Nb2O5 setelah proses pemanggangan dan pelindian. Hasil pemanggangan didapatkan distribusi massa terbanyak pada ukuran mesh +100 dan terjadi peningkatan kadar Ta2O5 dan Nb2O5 berturut-turut meningkat sebanyak 21,1% dan 37,5%. Kadar yang dihasilkan dari pelindian dengan 4 M NaOH meningkat sebanyak 3,48 dan 1,75 kali lipat dari Ta2O5 dan Nb2O5 awal. Secara keseluruhan rangkaian penelitian khususnya setelah pelindian HCl memperoleh peningkatan kadar mencapai 1,51% Ta2O5 pada 1 M HCl dan 1,41% Nb2O5 pada 4 M HCl.ABSTRACTThe source of tantalum and niobium were known include as critical in mid term. The tin slag is a waste which could be a secondary resource. This research to found the effect of 700 oC roasting and concentration variable of NaOH and HCl solution as leaching reagent, the sample used Indonesian tin slag which have initial grade 0.33% Ta2O5 dan 0.64% Nb2O5.The change of Ta2O5 and Nb2O5 grades were determined by XRF test after roasting and leaching. The highest mass distribution on +100 mesh as the roasting result and the grades were increased 21.1% and 37.5% for Ta2O5 and Nb2O5. The results of leaching 4 M NaOH were increased of about 3.48 and 1.75 times from initial grade. From the whole of results, especially after HCl leaching were increased to 1.51% Ta2O5 on 1 M HCl and 1.41% Nb2O5 on 4 M HCl.;The source of tantalum and niobium were known include as critical in mid term. The tin slag is a waste which could be a secondary resource. This research to found the effect of 700 oC roasting and concentration variable of NaOH and HCl solution as leaching reagent, the sample used Indonesian tin slag which have initial grade 0.33% Ta2O5 dan 0.64% Nb2O5.The change of Ta2O5 and Nb2O5 grades were determined by XRF test after roasting and leaching. The highest mass distribution on +100 mesh as the roasting result and the grades were increased 21.1% and 37.5% for Ta2O5 and Nb2O5. The results of leaching 4 M NaOH were increased of about 3.48 and 1.75 times from initial grade. From the whole of results, especially after HCl leaching were increased to 1.51% Ta2O5 on 1 M HCl and 1.41% Nb2O5 on 4 M HCl., The source of tantalum and niobium were known include as critical in mid term. The tin slag is a waste which could be a secondary resource. This research to found the effect of 700 oC roasting and concentration variable of NaOH and HCl solution as leaching reagent, the sample used Indonesian tin slag which have initial grade 0.33% Ta2O5 dan 0.64% Nb2O5.The change of Ta2O5 and Nb2O5 grades were determined by XRF test after roasting and leaching. The highest mass distribution on +100 mesh as the roasting result and the grades were increased 21.1% and 37.5% for Ta2O5 and Nb2O5. The results of leaching 4 M NaOH were increased of about 3.48 and 1.75 times from initial grade. From the whole of results, especially after HCl leaching were increased to 1.51% Ta2O5 on 1 M HCl and 1.41% Nb2O5 on 4 M HCl.]"

"ABSTRAKNegara Indonesia adalah negara yang kaya akan kandungan unsur mineral berharga pada sumber daya alamnya terhususnya dalam bidang pertambangan. Terak nikel adalah salah satu hasil mentah atau slag dari pemurnian kadar unsur ndash; unsur berharga dimana yang berasal dari perut bumi Indonesia yang didalamnya banyak mengandung mineral berharga seperti Magnetite Fe3O4, Pendlandite Fe,Ni 9S8, Nickel Iron NiFe, dan Bornite CuFeS4. Studi penelitian ini bertujuan untuk mengetahui pengaruh kadar pH terhadap effisiensi pengambilan kadar unsur nikel dan kobalt pada proses pelindian asam ndash; basa menggunakan larutan H2SO4 0,2 M dan NH4OH pada variasi pH yang beragam. Berdasarkan hasil XRD dan AAS, diperoleh hasil yang cukup signifikan pada hasil pelindian pada pH 9.

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ABSTRACTIndonesia is a country rich in the content of valuable mineral elements in its natural resources particularly in the field of mining. Nickel matte is one of the crude or slag results of purifying the precious elements of which are derived from the nature of the Indonesian earth in which it contains many valuable minerals such as Magnetite Fe3O4, Pendlandite Fe,Ni 9S8, Nickel Iron NiFe, and Bornite CuFeS4. This research study aims to determine the effect of pH levels on the efficiency of taking the element content of nickel and cobalt in the acid base leaching process using a solution of H2SO4 0.2 M and NH4OH on various pH variations. Based on XRD and AAS results, significant results were obtained in leaching results at pH 9. "

"Logam tantalum dan niobium merupakan logam bernilai ekonomi tinggi yang banyak dimanfaatkan dalam berbagai aplikasi terutama sebagai kapasitor dan paduan pada baja paduan super, tetapi keberadaan logam ini digolongkan ke dalam 14 critical materials. Terak timah hasil dari proses peleburan konsentrat bijih timah merupakan mineral yang memiliki potensi sebagai sumber sekunder dalam pengolahan logam tantalum dan niobium. Penelitian ini berfokus pada peningkatan kadar unsur tantalum dan niobium dari terak timah PT Timah Tbk dengan kadar Ta 0,23 dan Nb 0,47 melalui metode pelindian NaOH dan variasi konsentrasi asam fosfat. Sebelum proses pelindian, sampel terak timah dilakukan pemanggangan pada temperatur 900 oC selama 2 jam dan pendinginan cepat dalam media air untuk melihat morfologi struktur yang memiliki celah antar butir, dikarakterisasi dengan SEM. Kemudian, dilakukan pelindian menggunakan NaOH dan H3PO4, dimana masing-masing residunya dikarakterisasi dengan XRF sementara filtrat hasil pelindian dikarakterisasi dengan AAS dan ICP-OES. Hasil penelitian menunjukkan bahwa pelindian NaOH dapat menurunkan kadar unsur pengotor Fe, Ca, Ti, Al pada residu serta diperoleh kadar Ta tertinggi sebesar 0,85 pada pelindian H3PO4 0.5 M dan kadar Nb tertinggi sebesar 1,45 pada pelindian H3PO4 1.0 M.

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Tantalum and niobium metal are high value metals that widely used in various applications, especially as capacitors and alloys in super alloy steel, but the presence of these metals is classified into 14 critical materials. Tin slag that produced from tin ore concentrate smelting process is a mineral that has a potential as a secondary source in the processing of tantalum and niobium. This study focuses on upgrading of tantalum and niobium content from tin slag PT Timah Tbk with content of Ta is 0.23 and Nb 0,47 by NaOH leaching process and variable concentration of phosphoric acid as a leaching agent. Before leaching process, the tin slag sample was roasted at 900 C for 2 hours and water quenching to observe the morphology of gap between the grains, characterized by SEM. Then, leaching was done using NaOH and H3PO4, where each residue was characterized by XRF while the leaching filtrate was characterized by AAS and ICP OES. The results showed that NaOH leaching could decrease the content of Fe, Ca, Ti, Al on residues and obtained the highest Ta content of 0.85 in leaching H3PO4 0.5 M and the highest Nb content of 1.45 in leaching H3PO4 1.0 M."

"Bijih nikel laterit merupakan cadangan utama nikel di dunia. Salah satu negara yang mengandung bijih ini adalah Indonesia. Bijih nikel laterit Indonesia umumnya dalam jenis limonit. Mineral utama yang terkandung dalam limonit adalah goetit. Mineral ini mengandung unsur utama besi dengan unsur-unsur pengotor, antara lain nikel dan kobalt. Studi penelitian terkait pelindian limonit telah dikembangkan yang bertujuan untuk mengetahui pengaruh konsentrasi NaOH terhadap kadar akhir nikel dan kobalt. Hasil pengujian XRD menunjukan adanya senyawa nikel dan kobalt yang dihasilkan dalam pelindian. Hasil pengujian AAS menunjukan persentase kadar akhir nikel dan kobalt bernilai negatif. Konsentrasi berpengaruh terhadap fluktuasi kadar akhir nikel dan kobalt.

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Nickel laterite ore is a primary nickel reserve on Earth. One of the countries that contain this kind of ore is Indonesia. Indonesian nickel laterite ore is commonly a limonite type. The main mineral consisted in limonite is goethite. This mineral is composed of a substantial component of iron along with impurity elements, among them are nickel and cobalt. Research studies concerning limonite leaching have been developed in order to determine the effect of NaOH concentration on nickel and cobalt. The XRD test result has shown the existence of nickel and cobalt compounds created in leaching. The AAS test result has shown that the final content percentages of nickel and cobalt are negative. Concentration has affected the fluctuation of final contents of nickel and cobalt."