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All Journal International Journal of Acta Material
L. Agusu
Department of Physics, Faculty of Mathematics and Natural Science, University of Halu Oleo, Kendari 93232, Indonesia
Chemistry Materials Science & Nanotechnology Physics

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Microwave-Assisted Roasting-Leaching of Nickel from Indonesian Nickel Laterite Ore A. J. Muhammad; K. Nakagawa; I P. A. Karya; A. Ndita; L. O. M. Darusman; T. Iwamoto; Y. Terui; L. Agusu; I. N. Sudiana; F. Nishimura; T. Nishiumi; T. Asano; H. Kikuchi; S. Mitsudo
International Journal of Acta Material Vol. 1 No. 2 (2025): February 2025
Publisher : Faculty Mathematics and Natural Sciences, Halu Oleo University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.62749/ijactmat.v1i2.10

Abstract

This study investigated nickel extraction from nickel laterite ore from Indonesia using the microwave roasting leaching method. The study focused on investigating the effect of microwave power and roasting temperature on the extraction of nickel. Samples from each step were characterized using X-ray diffraction (XRD) and Atomic Absorption Spectroscopy (AAS). The method has the advantage of being carried out in atmospheric conditions with high nickel extraction at low temperatures, a rapid process, and without pre-roasting as in conventional roasting. It was obtained that 92.8% of nickel was extracted by application of microwave power at 540 W, at a roasting temperature of approximately 335°C for 30 minutes. The maximum result were obtained when the heating temperature is near to the boiling point of sulfuric acid (337oC). However, the amount of nickel extracted decreases when the heating temperature is above the boiling point of sulfuric acid. The results of XRD analysis of samples after roasting and solid leaching residue samples also revealed that the maximum nickel recovery occurred when the roasting process had transformed all iron sulfate-aqueous system (Fe(OH)(SO2)2.4H2O) into iron sulfate (Fe2(SO4)3) which also directly changed NiSO4.6H2O into NiSO4 which is highly soluble in water.
Fabrication and Characterisation of Semi-Solid DSSCs Using Reduced Graphene Oxide (rGO) from Coal as a Filler in Polymer Gel Electrolytes W. O. Sukmawati; L. Ardan; I. Saleh; L. Agusu; I N. Sudiana; I. Usman
International Journal of Acta Material Vol. 2 No. 1 (2025): August 2025
Publisher : Faculty Mathematics and Natural Sciences, Halu Oleo University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.62749/ijactmat.v2i1.16

Abstract

In an effort to enhance the conductivity of TMSPMA-based polymer gel electrolytes (PGE), this study incorporated reduced graphene oxide (rGO) as a filler within the PGE matrix. The rGO was synthesized from sub-bituminous coal utilizing a modified Hummer method, while the PGE was formulated through a sol-gel process involving TMSPMA with varying proportions of rGO relative to the PGE. X-ray diffraction (XRD) measurements confirmed the presence of rGO, revealing a peak at a 2θ angle of 24.830° and a calculated crystalline size of 30.44 nm. Fourier-transform infrared spectroscopy (FTIR) characterization indicated that the identified functional groups were consistent with the molecular structure of TMSPMA. Impedance measurements conducted using an LCR meter demonstrated that the incorporation of rGO up to 0.04 g significantly enhanced the conductivity, achieving a value of 0.013 S/cm. Furthermore, photovoltaic performance testing of dye-sensitized solar cells (DSSC) indicated that the highest efficiency of 1.03% was attained with the PGE containing 0.04 g of rGO.
Development of Eco-friendly Antimicrobial Bricks Using Nickel Slag Waste Enriched with TiO2 to Counteract E. coli Contamination L. Agusu; W. O. Nurtia; M. Z. Muzakkar; I W. Sutapa; Y. Ishikawa; Y. Fujii; T. Asano; S. Mitsudo; Y. Tatematsu
International Journal of Acta Material Vol. 2 No. 1 (2025): August 2025
Publisher : Faculty Mathematics and Natural Sciences, Halu Oleo University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.62749/ijactmat.v2i1.20

Abstract

This study investigates the use of nickel slag waste, enriched with TiO2, as a sustainable material for producing antimicrobial bricks. The research focuses on evaluating the impact of variations in firing time and the addition of nickel slag on the mechanical properties of the bricks, as well as their antibacterial effectiveness against E. coli bacteria. The bricks were produced using an electric furnace with different composition ratios of clay, nickel slag, and TiO2. Results demonstrate that the optimal compressive strength of the bricks is 21.673 × 10⁵ N/m², achieved with a clay:slag:TiO2 ratio of 90:5:5 at a firing temperature of 1000°C for 12 hours. The water absorption rate for this composition was found to be 16.98%. Antimicrobial tests, using the scatter method, revealed that TiO2-enriched bricks significantly inhibited E. coli growth, with only two colonies present compared to 77 colonies on bricks without TiO2. X-ray diffraction (XRD) analysis confirmed the presence of key oxides such as SiO2, TiO2, and CaCO3. These findings suggest that nickel slag, when combined with TiO2, can be an effective additive in clay-based bricks to inhibit E. coli growth, offering potential for applications in water purification and environmental sustainability. Furthermore, the use of advanced heating techniques such as microwaves or gyrotrons may enhance the bricks’ structural integrity and antimicrobial performance in future applications.
Investigation of the Mineral Content of Laterite Soil and Nickel Ore in the Nickel Mining Area of PT Vendoura Inti Perkasa, Bahodopi District, Morowali Regency W. S. Nurjannah; L. Agusu; R. Eso
International Journal of Acta Material Vol. 2 No. 2 (2026): February 2026
Publisher : Faculty Mathematics and Natural Sciences, Halu Oleo University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.62749/ijactmat.v2i2.25

Abstract

This study aims to identify and analyze the mineral composition of lateritic soils in a nickel mining area. Sampling was conducted vertically at 50 cm intervals, reaching 700 cm and covering four laterite soil layers: topsoil, limonite, saprolite, and bedrock. The materials were dried, crushed, and sieved using a 200-mesh screen. The samples were then analyzed for elemental content using X-ray fluorescence (XRF) and for mineral composition using X-ray diffraction (XRD). The XRF results show that SiO₂ and MgO are more concentrated in the bedrock and saprolite layers, while Fe and Al₂O₃ are more dominant in the topsoil and limonite layers. The presence of goethite (hydroxide) in the limonite layer at both points indicates hydrated iron oxides typical of lateritic profiles. Hematite (oxide) was found in the limonite rock at Point 1, while antigorite and chrysotile (silicates) were found at Point 2. In the saprolite layer, hematite was identified at Point 1 and goethite at Point 2. In the bedrock, lizardite was found at Point 1 and olivine at Point 2, suggesting a parent material of weathered ultramafic or metamorphic origin. The presence of goethite confirms typical characteristics of lateritic soils rich in hydrated iron oxides.
Synthesis and Characterization of NaOH-Doped ZnO Metal Oxide Thin Films for Electron Transport Layer in Dye-Sensitized Solar Cells (DSSCs) W. S. Arsyad; H. A. Hangkea; I. Saleh; I N. Sudiana; L. Agusu; I. Usman
International Journal of Acta Material Vol. 2 No. 2 (2026): February 2026
Publisher : Faculty Mathematics and Natural Sciences, Halu Oleo University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.62749/ijactmat.v2i2.30

Abstract

Research on the manufacture of ZnO thin films as electron transport layers has been carried out. The ZnO coating was prepared by sol-gel method. At the time of making the solution precursor, the doping given was 0.72%, 1.09%, and 1.45% by weight. Each hkl index changes at an angle of 2θ which causes the mean crystal size to decrease from 57.57 nm, 35.94 nm to 24.01 nm for doping concentrations of 0.72%, 1.09% and 1.45%, respectively. The measurement results using the LCR meter show that the resistance of the ZnO thin layer increases with the addition of NaOH doping from 125.49 Ω.cm, 462.93 Ω.cm and 3192.8 Ω.cm for doping are 0.72%, 1.09% and 1.45% NaOH respectively. The results of the analysis of the UV-Vis spectrometer, the slit energy value decreased with the increase in the doping of NaOH given, namely 2.03 eV, 2.026 eV, 2.025 eV and 2.024 for samples without doping are 0.72%, 1.09% and 1.45% sequentially. The results of the morphological analysis using SEM showed that the grains with sizes and shapes tended to be the same in all thin film samples.
Co-Authors A. J. Muhammad A. Ndita F. Nishimura H. A. Hangkea H. Kikuchi I N. Sudiana I P. A. Karya I W. Sutapa I. N. Sudiana I. Saleh I. Usman K. Nakagawa L. Ardan L. O. M. Darusman M. Z. Muzakkar R. Eso S. Mitsudo T. Asano T. Iwamoto T. Nishiumi W. O. Nurtia W. O. Sukmawati W. S. Arsyad W. S. Nurjannah Y. Fujii Y. Ishikawa Y. Tatematsu Y. Terui