Doping Calcia and Yttria into Zirconia Obtained from by Product of Tin Concentrator to Improve its Ionic Conductivity

Abstract. Zirconia has been prepared from Zircon concentrate by caustic fusion methods. Zircon is a by product from tin ore concentration plant at Bangka island of Indonesia. Yttria Stabilized-Zirconia (YSZ) was prepared by introducing the 8 % mol yttrium oxide into zirconia and sintered at 1500 �C for 5 hours. In order to obtain constant oxygen vacancy of 8 % mol in Zirconia, an appropriate amount of Yttria and Calcia were introduced into Zirconia and the mixtures were heated at 1350 oC for 5 hours. Elemental composition was determined by SEM/EDX and XRF and lattice parameters were determined using X-ray diffraction method. Ionic conductivity was measured by complex impedance spectroscopy. The results show that doping of Yttria into Zirconia (YSZ) and Calcia-Yttria into Zirconia (CYZ) allows phase transformation of Zirconia from tetragonal with space group P42/nmc into cubic Fm3m and enhance the ionic conductivity. However, the prepared materials are porous and have not met the requirement for the electrolyte material yet

UTILISATION OF SLAG POWDER FOR CEMENT SUBSTITUTION BASED ON THE COMPRESSIVE STRENGTH AND PENETRATION OF CHLORIDE IONS

UTILIZATION OF SLAG POWDER FOR CEMENT SUBSTITUTION BASED ON THE COMPRESSIVE STRENGTH AND PENETRATION OF CHLORIDE IONS. The availability of waste from nickel ore smelting in the form of slag has increased, this is due to the high nickel production to meet the increasing needs for development and for compound- ing materials for construction materials. This research aims to make a paste from the mixture of Nickel Pig Iron (NPI) slag from PT Indoferro which is used as a substitute for making cement paste. The materials used in this study are cement, nickel slag, water, and zeolite. The cement paste is made with a dimension of 10 cm x 5 cm with each slag used as an amplifier on the paste with a volume variation of 15%, 30%, 45%, and 60%. Each material is weighed according to mix design then mixing the materials, after they are homogeneous, they are put into the mold and then let stand for 24 hours until the paste solidifies and hardens, after 24 hours, the paste sample is removed from the mold and treated at room temperature, after the life is qualified, the paste sample is tested. Results of the compression test show that variations of slag addition to the paste mixture giving maximum compressive strength is the 15% variant for NPI slag. The increase in compressive strength of the slag mixture paste may occur because slag contains cement compounds which can chemically react with Calcium Hydroxide (CH) com- pounds as a result of the hydration reaction of cement with water to form a Calcium Silicate Hydrate (CSH) compound from the hydration result between water and cement to increase adhesion and compressive strength on cement paste

Doping Calcia and Yttria into Zirconia Obtained from by Product of Tin Concentrator to Improve its Ionic Conductivity

Zirconia has been prepared from Zircon concentrate by caustic fusion methods. Zircon is a by product from tin ore concentration plant at Bangka island of Indonesia. Yttria Stabilized-Zirconia (YSZ) was prepared by introducing the 8 % mol yttrium oxide into zirconia and sintered at 1500 "žaC for 5 hours. In order to obtain constant oxygen vacancy of 8 % mol in Zirconia, an appropriate amount of Yttria and Calcia were introduced into Zirconia and the mixtures were heated at 1350 oC for 5 hours. Elemental composition was determined by SEM/EDX and XRF and lattice parameters were determined using X-ray diffraction method. Ionic conductivity was measured by complex impedance spectroscopy. The results show that doping of Yttria into Zirconia (YSZ) and Calcia-Yttria into Zirconia (CYZ) allows phase transformation of Zirconia from tetragonal with space group P42/nmc into cubic Fm3m and enhance the ionic conductivity. However, the prepared materials are porous and have not met the requirement for the electrolyte material yet

CHARACTERISTICS OF ZrO2 ADDED-MgAl2O4 CERAMICS FOR MATRIX OF INERT MATRIX NUCLEAR FUEL (IMF)

CHARACTERISTICS OF ZrO2 ADDED-MgAl2O4 CERAMICS FOR MATRIX OF INERTMATRIX NUCLEAR FUEL (IMF). Some ZrO2 added-MgAl2O4 ceramics for inert matrix of inertmatrix nuclear fuel (IMF) had been fabricated from powders prepared using precipitationmethod. Effect of ZrO2 addition on crystal structure, microstructure and mechanical properties ofthe ZrO2 added-MgAl2O4 ceramics was studied. The ceramics were prepared by mixing ZrO2,MgO and Al2O3 followed by pressing and sintering. The concentrations of ZrO2 additive were 0,5, 10 and 15 mole %. The mixed powder was pressed into green pellets with pressure of4 ton/cm2. The green pellets were sintered at 1600 oC for 2 hours in air. The sintered pelletswere evaluated visually. For microstructure examination, the fractured samples were examinedusing a scanning electron microscope (SEM). Crystal structure of the samples was analyzedusing x-ray diffraction (XRD). Hardness and fracture toughness of the sintered pellets weredetermined using microindentation method with aid of a Vickers microhardness tester fromZwick. It was known that the sintered pellets were visually good. The XRD data showed that theceramics crystallized in spinel cubic with second phase of ZrO2.. The hardness and fracturetoughness of the ceramics increased with the increase of ZrO2 concentration

TEKSTUR DEFORMASI DAN REKRISTALISASI BAJA LEMBARAN CANAI DINGIN BEBAS INTERSTISI

TEKSTUR DEFORMASI DAN REKRISTALISASI BAJA LEMBARAN CANAI DINGIN BEBAS INTERSTISI. Perkembangan tekstur kristalografi dipelajari pada baja lembaran bebas interstisi canai dingin. Tekstur yang diamati adalah tekstur deformasi setelah pencanaian dingin dan tekstur rekristalisasi atau tekstur annealing setelah proses annealing. Tekstur deformasi baja lembaran bebas interstisi dipelajarimelalui variasi persen reduksi ketebalan dengan selang reduksi antara 50,5% hingga 90 %. Sementara tekstur rekristalisasi dipelajari melalui variasi laju pemanasan annealing antara 32 oC/jam hingga 128 oC/jam, variasi waktu penahanan annealing antara 5 jam hingga 20 jam dan variasi suhu annealing dari 700 oC hingga 900 oC. Perkembangan tekstur deformasi dan rekristalisasi dipelajari melalui pengujian difraksi sinar-X. Tekstur kristalografi diukur untuk tekstur yang mempengaruhi sifat mampu bentuk, yaitu tekstur [111] dan tekstur [100]. Pengujian tarik terhadap spesimen pada orientasi yang berbeda terhadap arah pencanaian kemudian dilakukan untuk memperoleh nilai r yang merupakan parameter sifat mampu bentuk baja lembaran

ANALISIS LAJU DEGRADASI RHODAMINE B (RhB) PADA PROSES FOTOKATALISIS TiO2

Abstract:. The photocatalysis of TiO2 process occurs due to electrons transition in the valence band are excited to the conduction band when light hitting of TiO2 surface having greater energy than the bandgap energy. Rhodamine B (RhB) as a test solution is used to measure the degradation rate and photocatalytic efficiency of Anatase TiO2 (TiO2 A), mixture of Anatase and Rutile TiO2 (TiO2 Ar), Merck Anatase TiO2 (TiO2 M) and mixture of Merck and Rutile Anatase TiO2 (TiO2 Mr). The variables used were solid percent TiO2 (0%; 0.1%; 0.2%; 0.3% and 0.4%), the concentration of the test solution (5, 10, 15, 20 and 25 ppm) and the solar radiation time (30, 60, 90, 120 and 150 minutes). The results got showed that TiO2 A had the highest degradation rate among other TiO2 of 0.0087/minute and the highest photocatalysis efficiency was TiO2 M at 75% solid variable, TiO2 A at a variable concentration of test solution and radiation time respectively 83% and 71%.Keyword: TiO2, photocatalysis, rhodamine B.Abstrak: Proses fotokatalisis TiO2 terjadi karena elektron yang berada pada pita valensi tereksitasi ke pita konduksi akibat dari cahaya yang mengenai permukaan TiO2 memiliki energi lebih besar dibandingkan energi celah pitanya. Rhodamine B (RhB) digunakan sebagai larutan uji untuk mengukur laju degradasi dan efisiensi fotokatalisis TiO2 Anatase (TiO2 A), TiO2 campuran Anatase dan Rutile (TiO2 Ar), TiO2 Anatase Merck (TiO2 M) dan TiO2 campuran Anatase Merck dan Rutile (TiO2 Mr). Variabel yang digunakan adalah persen solid TiO2 (0%; 0,1%; 0,2%; 0,3% dan 0,4%) konsentrasi larutan uji (5, 10, 15, 20 dan 25 ppm) serta waktu radiasi matahari (30, 60, 90, 120 dan 150 menit). Hasil yang diperoleh menunjukkan bahwa TiO2 A memiliki laju degradasi paling tinggi diantara TiO2 lainnya sebesar 0,0087/menit dan efisiensi fotokatalisis tertinggi yakni TiO2 M pada peubah persen solid sebesar 75%, TiO2 A pada peubah konsentrasi larutan uji dan waktu radiasi masing-masing sebesar 83% dan 71%.Kata Kunci: TiO2, fotokatalisis, rhodamin B

Electrical Properties of Various Composition of Yttrium Doped-Zirconia Prepared from Local Zircon Sand

Doping yttrium ions, Y3+ into ZrO2 produced Yttria-Stabilized Zirconia, YSZ. Various amount of yttrium ions could provide different ionic conductivity. This research investigated electrical conductivity of various YSZ composition, i.e., 4.5; 8.0 and 10% mol yttrium in ZrO2. The ZrO2 powder used was synthesized from zircon sand, a side product of tin mining plant, Bangka Island, Indonesia. Structural investigation on the prepared YSZ found that yttrium ion doping has changed the crystal structure of ZrO2 from monoclinic to cubic, even though the monoclinic and tetragonal are also still exist. The Y3+ doping changed the cell parameter of ZrO2 crystal. It indicates that the Y3+ entered into the ZrO2 structure and produced vacancy sites. The highest ionic conductivity is provided by 8% mol Yttrium doping or 8YSZ, i.e., 2.74×10-4 S.cm-1 at 700oC with an activation energy of 0.741 eV

Pengaruh Konsentrasi Tembaga dan Rapat Arus terhadap Morfologi Endapan Elektrodeposisi Tembaga

Copper deposits have been obtained by the electrolysis method using copper sulfate and sulfuric acid. The effect of copper concentration and current density on the surface morphology of copper deposits and current efficiency have been studied. The variation of copper concentration is 0.04 M and 0.8 M and the variation of current density is 2-8 A/dm2. The copper deposits will be photographed macro, weighed and characterized by Scanning Electron Microscope (SEM) to determine the surface morphology of deposits and Energy-Dispersive X-ray spectroscopy (EDX) to determine the chemical composition of deposits. The surface morphology of copper deposits in the form of compact and without nodules was reached at copper concentration is 0.8 M and the current density is 2 A/dm2 with the average of current efficiency is 96%

Study of Reduced Graphene Oxide addition on the Electrical Conductivity and Flexural Strength of Metakaolin-based Geopolymer

Geopolymer with reduced Graphene Oxide (rGO) composite obtanined through Hummers method. This material is a substitute option for graphene because the nature of rGO is easier to produce in large quantities. In theory, it is expected that rGO can increase the flexural strength and electrical conductivity of geopolymer. The rGO composition used varies from 0-1 wt%. Geopolymer and their constituents were characterized by the Three Point Bending, EIS, SEM, FTIR, XRD, and XRF tests. Fly ash-based geopolymers have a flexural strength of 5.2 MPa at a composition of 0.5 wt% rGO, while metakaolin-based geopolymers with an addition of 0.25% rGO produce the highest flexural strength of 5.53 MPa. A frequency of 100,000 Hz tends to facilitate greater electrical conductivity, on fly ash-based geopolymers found electrical conductivity of 5.08 x 10-3 S / m, while for metakaolin-based geopolymers the electrical conductivity is higher ie 1.01 x 10-1 S / m.