Papers by Keyword: Calcination

Abstract: In the 18th century, hydraulic-based binders gradually supplanted air-hardening binders, and by the early 20th century, these were eventually replaced by cement. The distinction between binders categorized as natural and other hydraulic binders, such as natural cement and conventional cement, is that the former is characterized by raw materials with a naturally favorable mineralogical composition. This study examined the experimental possibilities of natural hydraulic binder production with marl resources commonly found in Turkey. Two raw materials quarried from Mersin (M) and Adana (A) were selected. These raw materials were calcined at temperatures of 750-850-950-1050 °C. The X-ray diffraction (XRD) analysis indicates that while the binders produced with M-coded raw materials contain varying amounts of the hydraulic phases larnite (C₂S and C₃S), the A-coded binders exhibit an absence of these critical hydraulic phases, which are essential for strength development in hydraulic binder paste. The increase in the strength of A-coded binders is thought to be due to the formation of calcium silicate hydrate (C-S-H) phases, which result from the reaction between water, clay minerals (SiO₂, Al₂O₃, and Fe₂O₃), and hydrated lime (portlandite, Ca (OH)₂).

Abstract: The development of energy storage capacitors with high dielectric constant and good stability has been focused on by researchers due to many issues regarding environmental protection and energy conservation. Barium-Strontium Titanate based ceramic capacitors are widely used for energy storage applications due to their attractive dielectric properties. In this study, (Ba_0.90Sr_0.10) TiO₃ based capacitors were produced, and the influence of additives i.e. CaZrO₃, MnCO₃, CeO₂, ZnO, and Nb₂O₅ was investigated. The parameters of all the fabrication processes have been optimized to get defect-free green and sintered samples. The defect-free green parts were sintered at 1380°C for 2 h and perovskite structure was confirmed by XRD profiles. The grain size was refined from 25 μm to 08 μm analyzed by scanning electron microscopy (SEM). The capacitor was tested at 40 KV successfully and capacitance of 2.0 nF was measured at this high voltage. The results showed that high-voltage capacitors can be fabricated with enhanced energy storage.

Abstract: During the calcination of kaolin particles, kaolinite is thermally activated at high temperatures, causing the crystal structure to collapse and yielding amorphous metakaolinite through dehydroxylation. This metakaolinite is used as a supplementary cementitious material, and one of the most important factors influencing the pozzolanic properties is calcination conditions. Fourier transform infrared spectroscopy (FTIR) has become useful in distinguishing and obtaining information about structural order-disorder and phase transformation following the calcination process. In this study, water-washed kaolin particles were thermally activated at elevated temperatures ranging from 600 to 800 °C for 3–4 h at a rate of 10 °C/min before being analyzed with FTIR to determine the optimum conditions for calcining kaolin particles by examining functional groups, and also to study structural order-disorder or crystallinity of calcined kaolin particles. The most reactive metakaolinite state of water-washed kaolin particles was achieved after 3 h of calcination at 800 °C. Using both empirical and numerical approaches, variations in the position and relative intensity of O-H stretching and deformation of hydroxyl groups in the infrared spectrum can be used to classify the degree of structural order of water-washed kaolin particles. By increasing the calcination temperatures and period, the well-ordered and partially-ordered structures of kaolin particles were transformed into well-ordered, partially-ordered, and poorly-ordered structures. These structural disorder and crystallinity have a significant impact on pozzolanic activity because well-ordered kaolinite can be transformed into less reactive metakaolinite, whereas poorly-ordered kaolinite with high defects can be transformed into more reactive metakaolinite. However, in this study, the structure of water-washed kaolin particles that achieved complete dehydroxylation was discovered to be partially-ordered to poorly-ordered and can be transformed into highly reactive pozzolans.

Abstract: A nickel laterite ore sample from the Obi Island of North Maluku, Indonesia was thermally treated using corncob charcoal as a reductant to determine the effect of corncob charcoal addition on the chemical change and phase transformation. Mineralogical analysis of raw ore sample and calcines was performed using optical microscopy and X-ray diffraction methods, whereas chemical composition was determined employing X-ray fluorescence (XRF) spectrometry. The ore was then calcined at 1.000°C for 1 hour with the mass variable of corncob charcoal as reductant was 5,10,15, and 20%. After calcination, the products were then weighed and analyzed using microscopic, XRD, and XRF methods. The results of material characterization showed that the ore sample is dominated by goethite. Antigorite, quartz, and hematite are also present in small quantities. The ore sample contains 1.53% Ni, 18.84% Fe, and an SM ratio of 2.46%. The experimental results showed that the optimum condition was achieved with the addition of 10% corncob reductant where the calcined product contains 1.88% Ni, 14.22% Fe, and SM ratio of 1.72. The increase of corncob charcoal addition >10% resulted in slight decrease of Ni reduction likely due to increase of Fe metallization.

Abstract: TiO₂ is the most widely used photocatalytic material to degrade waste compounds. To improve the photocatalytic performance of TiO₂, graphene nanoplatelets were used as doping on TiO₂. Graphene nanoplatelets are a hybrid between graphene and graphite. Graphene nanoplatelets have attractive features, including mechanical toughness, and for composite material applications. In this report, we investigate the effect of calcination on the synthesis of graphene nanoplatelets-TiO₂ synthesis material for photocatalytic processes. Graphene nanoplatelets-TiO₂ composites were prepared by stirring and evaporation methods. Then the composite was calcined at a temperature of 400°C, 500°C 600°C at intervals for 1, 2, 3 hours respectively. The composites were confirmed by X-ray diffraction (XRD), FTIR, SEM, BET, and UV-vis. The effect of calcination temperature on the surface, morphology, microstructure and photocatalytic activity of the graphene nanoplatelets-TiO₂ composite was investigated further. The photocatalytic performance of the graphene nanoplatelets-TiO₂ composite was evaluated for the photodegradation of phenol in an aqueous solution under a mercury lamp. Based on the results of the performance test in degrading phenol, the best results were obtained at a calcination temperature of 500°C for 3 hours. From the results of the characterization, it can be explained that 500°C calcination of this composite can improve the photocatalytic process in degrading of phenol.

Abstract: Bone tissue engineering has been used in the biomedical field to treat bone defects by implanting scaffolds into bone tissue. However, the currently developed scaffold still needs to be developed to obtain scaffold building materials with good compatible properties and can regenerate damaged bone cells. This study combines PVA/Chitosan polymer with CHA of tuna bone using the porogen leaching method at a calcination temperature of 100°C for 12 hours. The purpose of this study was to determine the physicochemical properties by characterizing XRD, SEM-EDX, FTIR, and the porosity of the scaffold. The results obtained from the results of the PVA/Chitosan/CHA XRD patterns are the formation of the PVA/Chitosan phase at 2θ(°)=19.68, the IR spectrum of the 𝑃𝑂₄³⁻group band and 𝐶𝐻₂ stretching, the ratio mol Ca/P is 1.98, the pore diameter is 1.561 ± 0.07 μm and the porosity is 55.04%. These results indicate that the PVA/Chitosan/CHA scaffold is an amorphous calcium phosphate (ACP) that has the potential for bone tissue engineering.

Abstract: The aim of the study was to determine the physicochemical and characterization of nano-calcium Catfish bone flour. The research implementation consisted of several stages: Preparation of fish bone meal, chemical characterization, physical characterization. The t test was used to see differences in treatment. The results of the research: chemical analysis of nano-calcium catfish bone flour revealed that it had a water content of 7.45%, ash 63.29%, protein 4.50%, lipid 2.95%, and carbohydrate 21.81%. Furthermore, both 33.15% calcined bone meal and the 32.16% non-calcined bone meal have calcium contents that meet the Quality I criterion. The findings of the physical characteristics test show nanoparticles in the uncalcined bone meal particle size, which is based on the percent number of 204.1 nm achieved with PI (degree of non-uniformity of particle distribution 0.403). And the calcined bone flour indicated the presence of nanoparticles and that their distribution tended to be uniform, with intensity percentages of 675.4 nm (86.1%) and 100.7 nm (13.9%), respectively. Visually, calcined nano-calcium flour is whiter in color than non-calcined nano-calcium flour. The advantages of alternative research for natural nanocalcium sources from catfish bone meal can be employed in food product manufacturing to satisfy the body's calcium requirements

Abstract: (1-x)BiFeO₃-xBaTiO₃-0.01KVO₃ with (x = 0.33 and 0.38) (abbreviated FTV33 and FTV38) was successfully prepared using three precursors that had been synthesized before the calcination process. BaTiO₃ was synthesized using the coprecipitation method, BiFeO₃ was synthesized using the sol-gel auto-combustion method, and KVO₃ was synthesized using the conventional solid-state method. Thermal analysis was carried out to determine the calcination temperature from 600 0C for 2h to 600 0C for 4h. X-ray diffraction (XRD) has been carried out to identify the phase after calcination at temperatures, respectively. The phase identification of the XRD pattern has been carried out by Match software shows that the powder and FTV33 and FTV38 have a pseudo-cubic structure with a P4mm space group and rhombohedral with an R3c space group. The XRD pattern is refined by the Rietveld method by Rietica software and the crystalline size is determined by MAUD software. The doping effect of KVO₃ on its electrical properties was systematically investigated and show that FTV33 is more conductive and has larger capacitance grains. Based on the previous XRD analysis, Ba²⁺ and K⁺ ions replaced Bi³⁺ at site A. On the other hand, Ti⁴⁺ and V⁵⁺ substituted Fe³⁺ at site B which was different from the host's oxidation state.

Abstract: Mixed oxide of titanium dioxide was synthesized by adding SnO₂ and CeO₂ through a precipitation method for the degradation of methylene blue (MB) under visible light. The as-prepared was dried and calcined at various temperatures, i.e. 450-750 °C. The calcined products were characterized by XRD, DRUV, and FTIR. The effect of calcination temperature was studied on the photodegradation of MB under visible light. The photocatalytic activity showed that calcined photocatalytic at 650 °C shows the lowest bandgap energy and the highest photocatalytic activity in the decomposition of methylene blue under visible light.

Abstract: This study aims to produce and characterize CaO (calcium oxide) from limestone, a natural product of Lobong Village. Calcination is the thermal decomposition of limestone to remove carbon so that it can produce calcium oxide. One of the functions of CaO is as an eco-friendly catalyst that does not produce toxic or hazardous waste and can be reused. CaO resulting from the calcination process at a temperature of 900°C for 1.5 h was characterized using XRD, SEM, FTIR, and EDS. XRD analysis of calcined limestone produced 2θ (h k l) diffraction peaks, namely 32.228^o (1 1 1), 37.389^o (2 0 0), 53.864^o (2 2 0), 64.169^o (3 1 1), and 67.404^o (2 2 2) which indicates the dominance of CaO. SEM analysis shows that the morphological structure of Lobong limestone after calcination is more porous than before. Studies by FTIR show that the chemical bonds of carbonate groups in the calcined limestone are decreasing. EDS analysis also shows that the mapping of carbon, which forms carbonates in calcined limestone, is decreasing.