Papers by Keyword: Kaolin

Abstract: The effect of Metakaolinization on the thermal and physicochemical properties of Badau Belitung kaolin is presented. Calcination of Badau Belitung kaolin indicated that kaolin was transformed to metakaolin at temperature above 500°C. The metakaolin was characterized using X-ray Diffraction (XRD), Fourier Transform Infrared (FT-IR) and Brunauer-Emmett-Teller (BET). The XRD diffraction pattern of the metakaolin was highly amorphous as a result of calcination effect on the raw kaolin. The FTIR spectra of the metakaolin produced showed that the material was thermally stable at temperature range of 500–700°C, whereas the specific surface area values of the raw kaolin and the metakaolin formed were increased with increasing calcination temperature from 500°C to 700°C.

Abstract: Synthesis strategy of hierarchical aluminosilicates was carried out by varying the starting material, type of a basic solution, and the hydrothermal condition. Aluminosilicate was synthesized using pre-treated low-quality kaolin by three kinds of basic solution, such as sodium hydroxide, sodium fluoride, and tetrapropyl ammonium hydroxide. The hydrothermal condition was carried out by gradual temperature and constant temperature. The desired mole ratio of Si/Al achieved by dealumination or by addition of silica. Products were characterized by X-ray diffraction, FTIR spectrometry, and nitrogen physisorption. Cation exchange was carried out on the product to obtain an acid catalyst. The acidity test of the catalyst was carried out by FTIR-pyridine spectrometry. The catalyst activity test was carried out to the acetalization reaction of 3,4-dimethoxybenzaldehyde with propylene glycol. The results showed that the catalyst synthesized with the basic solution of tetrapropyl ammonium hydroxide had the highest acid site number and the highest conversion of 3,4-dimethoxybenzaldehyde to acetal.

Abstract: Bamboo is a prospective biomass fuel due to its high heating value and growth rate. The addition of kaolin is necessary in the thermal conversion of biomass to increase its ash fusion temperature (AFT), thus reducing fouling and corrosion of the combustion system. This study evaluates the feasibility of utilizing bamboo-kaolin co-processing residue for geopolymer synthesis. Thermochemical calculations suggest that bamboo culm ash liquidus increases by 15% by adding kaolin during combustion at a biomass to kaolin mass ratio of 95:5%. A 2³ full factorial experiment measures the effect of activator Na₂SiO₃:KOH ratio, KOH concentration, and heat-curing period at 60 °C on the early strength of geopolymer mortars. Co-processing residue of bamboo-kaolin at a mass ratio of 95:5% produces geopolymer mortars with compressive strengths in the 10.7-40.3 MPa range. ANOVA treatment of the data indicate strong positive effect of KOH concentration. Crystalline phase characterizations indicate that the co-processing is able to convert kaolin to the amorphous, more reactive metakaolin. A shift in the IR absorption band from 1034 to 1008 cm^-1 is attributed to the conversion of Si-O-Si bonds of the co-processing residue into Si-O-Al and Si-O-K bonds of the geopolymer gel phase. These results suggest the feasibility of geopolymerization as a waste valorization pathway to ensure the sustainability of the biomass-based energy production.

Abstract: Hierarchical ZSM-5 was successfully synthesized by hydrothermal crystallization of kaolin clay. A statistical experimental design Taguchi method with analysis of variance (ANOVA) with an L₉ Orthogonal array (OA) was used to optimize the formation of high mesoporosity in hierarchical ZSM-5. Samples from kaolin mixtures crystallized at 80-175°C for 12, 24 and 48 h, respectively using hydrothermal followed by addition of mesoporogen cetyltrimethylammonium bromide (CTABr) surfactant. The presence of pentasil zeolite groups and large mesopores surface area and pore volume has observed on the samples by FTIR and N₂ adsorption-desorption technique.The optimum synthesis conditions studied by Taguchi analysis based on S/N ratio for temperature and time of hydrothermal. The optimum condition was 127.5°C and 48 h giving the highest mesoporosity. Data analysis of interaction plot for S/N ratio showed there was interaction between temperature and time in the crystallization of hierarchical ZSM-5. Hydrothermal temperature was the most influencing factors for the formation of hierarchical ZSM-5 with a percent contribution of 83%.

Abstract: Zeolite A and zeolite X was successfully synthesized from natural kaolin from Lampang province using calcination and two-step method of hydrothermal under the optimum conditions. Firstly, metakaolin was achieved by calcining the kaolin at 700 °C for 2 h. Secondly, hydrothermal experiments can be separated into two steps, the high temperature and short time of hydrothermal, metakaolin was mixed with NaOH to form hydrous sodium aluminosilicate, which was dissolved in dilute HCl. After the filtration, adjusted with deionized water to pH = 7 to form an amorphous aluminosilicate gel. Low temperature and longtime of hydrothermal, aluminosilicate gel was mixed with NaOH to form zeolite A and zeolite X. The optimum conditions for synthesis zeolite A is the high temperature and short time of hydrothermal with NaOH 8 M at 200 °C for 3 h and low temperature and longtime of hydrothermal with NaOH 1 M at 90 °C for 72 h. The optimum conditions for synthesis zeolite X is the high temperature and short time of hydrothermal with NaOH 8 M at 200 °C for 3 h and low temperature and longtime hydrothermal was NaOH 1 M at 90 °C for 120 h. The characterization of zeolite A and zeolite X were examined by x-ray diffraction (XRD), scanning electron microscopy (SEM), and infrared spectroscopy (FT-IR). Keywords: Zeolite A, zeolite X, Kaolin, Hydrothermal, Kaolin

Abstract: Geopolymer system which has high demand, especially among carbon conscious end users resulted in various research works on suitable mix designs of geopolymeric materials. There are certain factors that influence the properties of geopolymers such as composition, type and relative amount of alkali activator, NaOH concentration, specific surface composition of source materials, and condition during the initial period of the geopolymerization process. Focus of our work is on the degree of influence NaOH concentration has towards mechanical and bonding properties of kaolin geopolymer coated lumber wood. Other crucial parameters were kept constant at optimum that was deduced based on our earlier findings. The final idea is to create kaolin based coating material that is compatible with wood substrates which leads to a novel finding. To best of our knowledge, no researchers had attempted to do similar work before. Kaolin geopolymer coated lumber wood was prepared with varying NaOH concentration ranging from 2M to 14M. These pepared samples were tested after 7, 28 and 90 days to also analyse the changes in properties of kaolin geopolymer coated lumber wood over time. Samples were then subjected to mechanical and bonding testings such as flexural, adhesive, and water absorption as well. Morphological studies such as scanning electron microscopy were also performed to further evident findings from all testings.

Abstract: The comparison and analysis for the preparation of related performance indicators of the thermal protection such as the ablation resistance performance, thermal stability at high temperature and reflection ability of the heat ray of kaolin double-layer coated flexible composites were carried on. Because of the 2 d stratified structure of kaolin, and at the same time it processes the higher refractoriness, excellent resistance to the elevated temperature, the certain heat insulation and the reflection performance of the heat ray, the adequate padding of kaolin can improve the prepared thermal protection ability of double-layer coating of flexible composites.

Abstract: Presented work deals with the development of bio-source and biodegradable composite material for 3D printing. Polymer blend based on poly (3-hydroxybutyrate) (60 wt%) and poly (lactic acid) (25 wt%) plasticized by tributyl citrate (15 wt%) was used as a matrix. This base blend was filled with 10 vol% of kaolin or limestone. Zinc stearate was used for the surface treatment of the limestone samples. The mechanical and thermal properties of the composites, as well as their behavior during 3D printing process, were compared with unfilled blend and commercial poly (lactic acid) based 3D printing filament. Warping behavior, one of the main problems of 3D printing materials, was studied by means of warp coefficient. Cross-sections of specimens 3D printed under the same processing conditions were observed by the optical microscope. In the case of composite samples, individual filaments were separated. Despite the separation, composites filled with kaolin and with surface treated limestone exhibited satisfying mechanical properties. Scanning electron microscopy analysis confirmed good particle distribution of the samples with kaolin and surface treated limestone. No significant particle agglomerates were formed in the composites with limestone proving good dispergation ability of zinc stearate. Thermogravimetric analysis and Differential scanning calorimetry analysis showed no degradable effect of the used fillers on base polymer matrix. Observed results indicate that kaolin and surface treated limestone are suitable fillers for the bio-source composites used for 3D printing.

Abstract: Dental porcelain is one of the indirect restoration material with excellent aesthetic properties,on the other hand porcelain hardness frequently causing excessive wear of antagonist teeth. This study aiming to evaluate the effect of sintering temperature on the self-synthesized porcelain hardness. In this experiment, 25 porcelain samples were synthesized using Sumatran sand from Pangaribuan and Belitung regions, with the composition of 65 wt% Pangaribuan feldspar, 25 wt% Belitung silica and 10 wt% potassium salt. The samples were sintered in five different temperatures, which were 1110°C (A), 1120°C (B), 1130°C (C), 1140°C (D), and 1150°C (E). These samples were then invested on 5cm diameter resin each. The hardness was tested using Zwick Roell ZHμ Micro Vickers with 900 gram load for 15 seconds in 5 different indented areas for each sample. The result shows average hardness of 435.8 VHN (A), 461.0 VHN (B), 472.0 VHN (C), 487.6 VHN (D), and 528.7 VHN (E), which were increasing as the sintering temperature increased. Statistic result shows that sintering temperature significantly affected the hardness value of the porcelain (p value < 0.05). In conclusion sintering temperature affects the hardness of self-synthesized porcelain made from Sumatran natural sand without kaolin, although the average hardness of self-synthesized porcelain is still higher than average hardness of teeth enamel.

Abstract: The characterization of nanocomposites microcapsules made of biodegradable polymers is really important to science and technology, as different systems can be produced targeting unique properties. The aim of this study is to prepare and to evaluate oil loaded PHB/VMF2 microcapsules’ behavior in water. The microcapsules were analyzed by FTIR, SEM and XRD. The biodegradable nanocomposite present exfoliated clay (XRD) whose absorption at 989 cm^-1 (FTIR) indicates the Si-O stretching vibration, from VMF2. The microcapsules observed by SEM presented spherical shapes and some average diameters from 12 μm to 35 μm, depending on the composition of the shell and the presence or absence of the encapsulated oil. Compared to microcapsules’ shell made from PHB, those from the nanocomposite PHB/VMF2 proved to display better mechanical resistance thus very few fractured particles were observed by SEM.