Nurul Taufiqu Rochman

Characterization of Sumbawa manganese ore and recovery of manganese sulfate as leaching products

The aims of this research were to study the leaching process of manganese ore which originated from Sumbawa, Indonesia and its characterization. A high grade Indonesian manganese ore from Sumbawa, West of Nusa Tenggara was characterized by X-Ray Fluorescence (XRF). The result showed composition of 78.8 % Mn, 17.77% Fe and the rest were trace elements such as Si, Co, Ti, Zn, V and Zr contents. X-Ray Diffraction analysis showed that the manganese ore was consisted of pyrolusite (MnO2), rhodonite (MnSiO3), rhodochrosite (MnCO3) and hematite (Fe2O3). Manganese ore was also analyzed by thermal analysis to observe their thermal decomposition character. In this study, sulphuric acid (H2SO4, 6 M) was deployed as leaching agent. The leaching process was performed at 90 °C for two hours with the addition of NH4OH to control pH. Recovery percentage of leaching process yielded of 87 % Mn extracted. The crystallization process result at heating temperature of 200 °C was confirmed by XRD as manganese sulfate.The aims of this research were to study the leaching process of manganese ore which originated from Sumbawa, Indonesia and its characterization. A high grade Indonesian manganese ore from Sumbawa, West of Nusa Tenggara was characterized by X-Ray Fluorescence (XRF). The result showed composition of 78.8 % Mn, 17.77% Fe and the rest were trace elements such as Si, Co, Ti, Zn, V and Zr contents. X-Ray Diffraction analysis showed that the manganese ore was consisted of pyrolusite (MnO2), rhodonite (MnSiO3), rhodochrosite (MnCO3) and hematite (Fe2O3). Manganese ore was also analyzed by thermal analysis to observe their thermal decomposition character. In this study, sulphuric acid (H2SO4, 6 M) was deployed as leaching agent. The leaching process was performed at 90 °C for two hours with the addition of NH4OH to control pH. Recovery percentage of leaching process yielded of 87 % Mn extracted. The crystallization process result at heating temperature of 200 °C was confirmed by XRD as manganese sulfate.

Analysis of Structural and Microstructure of Lanthanum Ferrite by Modifying Iron Sand for Microwave Absorber Material Application

Analysis crystal structure of lanthanum ferrite by modifying iron sand has been carried out. Lanthanum ferrite included one of the functional materials which had composition of ABO3 perovskite system. The lanthanum ferrite is prepared by iron sand and lanthanum oxide powders. The mixture was milled for 10h with the various composition of lanthanum content. The samples are sintered at a temperature of 1000 °C for 10h. The microstructure analyses showed that the particle shapes was polygonal with the varied particle sizes and uniform distribution on the surface of the sample. The phase composition of refinement result showed that the lanthanum ferrite formed empirical compound of La0.8Mg0.2Fe0.7Ti0.2Si0.1O3. The La0.8Mg0.2Fe0.7Ti0.2Si0.1O3 phase has a structure orthorombic (P b n m) with lattice parameters a = 5.513(1) Å, b = 5.549(1) Å and c = 7.849(2) Å, α = β = γ = 90°, the unit cell volume of V = 240.2(9) Å3, and the atomic density of ρ = 6.293 gr/cm3. We concluded that this study has been successfully synthesized lanthanum ferrite material from modifying iron sand and has been understood changes in the parameters of the crystal structure and phase composition of this material. It was a great opportunity that the material can be used as a material candidate of absorber electromagnetic waves.

Controlling the Nanostructural Characteristics of TiO2 Nanoparticles Derived from Ilmenite Mineral of Bangka Island through Sulfuric Acid Route

The ilmenite mineral (FeO.TiO2) from Bangka Island-Indonesia is an important source for synthesizing TiO2 nanoparticles. However, the process is rather difficult since this mineral still contains many impurities and minor elements. Therefore, controlling the synthesizing route parameters is essential for obtaining the desired TiO2 nanoparticle characteristics. In the current work, we proposed a modified process involving the use of sulfuric acid through sol-gel method to provide titanyl sulfate (TiOSO4) solution as the inorganic precursor. For investigation purposes, several parameters were varied including volume ratio of water and titanyl sulfate, addition of iron powder (seeding) and dextrin coagulant, calcination time and temperature. The results showed that TiO2 nanoparticles can be succesfully synthesized using TiOSO4 precursor derived from Bangka ilmenite. Under all processing conditions, the resulting TiO2 nanoparticles have sphere-like shape and were indexed as the anatase TiO2 phase. The results also showed that the average particle size was reduce from 96 188 nm to 32 40 nm when the volume ratio of water and titanylsulfate was increased from 3:1 to 6:1. The addition of iron powder as seeding has improved the purity of TiO2 to ~ 95.01 wt%, in comparison to that of without seeding, which is ~92.78 wt%.

THE EFFECT OF ZnO PARTICLE ON ZINC PHOSPHATE CEMENT MICROSTRUCTURE

Dental cement based on zinc phosphate (Zinc Phosphate Cement) is the oldest dental cement that is still widely used today. One disadvantage of zinc phosphate-based dental cement is its low mechanical properties. In this study, ZnO nanoparticles are added to the zinc phosphate dental cement with the hypothesis that there will be the strengthening of the mechanical properties of dental cement. The fraction of ZnO nanoparticles were variedly added from 0.1 g, 0.5 g, 1 g and 1.5 g to the zinc phosphate dental cement which is then compared to the dental cement without the addition of ZnO nanoparticles. The materials were manually mixed and mold to form dental cement pellets (4 mm thick and 4 mm in diameter). Characterization of pellet hardness and strength result in a linear value to the addition of ZnO nanoparticles in which the value of hardness and strength increases as increasing of ZnO nanoparticles fractions. XRD analysis results indicate the appearance of peaks Zn 3 (PO 4 ) 2 .4H2O and ZnO compounds supported by the analysis of surface structure using SEM. The resulting dental cements have an increased value of hardness and compressive strength due to the improvement of its micro structure having a small amount of crack and a homogeneous distribution of nano ZnO. Through this phenomenon, it can be concluded that the addition of nano-ZnO can be applied to increase the value of hardness and strength in dental cement. Keywords: Nano Zn, Dental cement (Zinc Phosphate Cement).