Papers by Keyword: Feldspar

Abstract: An inert ceramic ball was prepared by using three kind of raw materials i.e. Selendang clay, silica sand, feldspar and distilled water. Selendang clay, silica sand, feldspar and distilled water were pre-mixed manually and compounded using a beaker. Universal testing machine (UTM) was used to test mechanical strength. Electron scanning microscope (SEM-EDX) was used for the study morphological feature and element mapping in the ceramic balls. X-ray powder diffraction (XRD) was used to determine the phase of crystalline material. The optimum sintering temperature was 1300 °C23 and got the strength of 238.8 kgf.

Abstract: The colossal dielectric permittivity of calcium copper titanate (CaCu₃Ti₄O₁₂, CCTO) provides a vast potential in miniaturizing electronic devices but become limited due to high dielectric loss. Hence, feldspar was introduced to reduce the dielectric loss and fill in the air gap of CCTO during the sintering process. The CCTO powder was prepared by the solid-state reaction method. The study focused on characterizing pure and feldspar added CCTO properties on phase formation and dielectric properties. The raw materials were weighed, followed by stoichiometric ratios for pure CCTO. While the addition of feldspar was added using a weight percentage ratio of 1%, 3%, 5%, 7% and 10%. The mixed powders were ball mixed for 24 hours using dry mixing. The mixed powder was calcined at 900°C for 12 hours and then pressed into a pellet with 6 mm diameter, then sintered at 1040°C for 10 hours. The X-ray Diffraction (XRD) machine and impedance analyzer were utilized to observe the phase formation and dielectric properties of the samples prepared. A single phase of CCTO was obtained after the sintering process except for pure CCTO and 1wt% of feldspar addition, and it still has remaining CuO in the ceramic. Even though feldspar can reduce the dielectric loss of the CCTO from 0.6 (pure CCTO) to 0.4 (10 wt%) at 1 MHz, it also hard to maintain the high dielectric constant. The dielectric constant of 1wt% of feldspar addition was recorded the highest value, up to 4000 at 1 MHz, while the lowest dielectric constant owned by 10wt% of feldspar addition, ~700 at 1 MHz.

Abstract: During the operation of porcelain stoneware sometimes there is a type of defects associated with crumbling from the edge of tile. In addition, cracks occur when a small object is fallen and during transportation of the products. Compared to conventional ceramic floor tiles, porcelain stoneware has increased strength, which explains its high price. The brittle failure is most likely, due to the hardening of glassy phase of tiles during cooling stage of the firing process. As a rule, the quenching temperature depends on the chemical composition of the glassy phase formed during firing. Both the phase and chemical composition of porcelain stoneware, and the chemical composition of the glassy phase are determined.

Abstract: This paper deals with the possibility of obtaining FeSiAl complex alloy by carbothermic reduction in a submerged arc furnace using aluminum dross, mill scale and feldspar.Bench scale experiments are carried out to clarify the effect of different variants such as reducing agent, basicity, and mill scale content of the charge on the metallic yield and chemical composition of the produced alloy.It was possible to get FeSiAl alloy containing 22% Si and 18% Al. the results reveal that to obtain such alloy less than 20% mill scale must be involved in the charge and the coke with amount 1 stoichiometric must be used.

Abstract: The Nossa Senhora do Carmo mining company, located at the southern of Santa Catarina (SC), Brazil, explores a large amount of feldspar to the ceramic market. As a result, waste is inevitable in the production and processing of the feldspar mineral, which results in an environmental impact. Therefore, this study aims to evaluate the effect of the addition of the waste coming from the feldspar mining in the composition of ceramic bricks. In this way, the waste and a clay mineral were characterized. The waste (0, 5, 15 and 25 wt%) was added to a composition of clay brick based on a standard clay from Morro da Fumaça, Santa Catarina, Brazil. Specimens were extruded and sintered at temperatures of 1123, 1223, and 1323 K. The technological properties assessed in this study were linear shrinkage, water absorption and bending strength. The data were assessed by analysis of variance. The results showed the feasibility of adding 15 and 25 wt% of waste to the brick composition. All technological properties were improved when compared to pure samples, except for linear shrinkage. The analysis of variance showed significant and reproducible effects for the water absorption results. The results for linear shrinkage and bending strength showed no statistical significance.

Abstract: This study aims to develop eco-friendly materials that can reduce the high unit weight of carbonate cement, as typical ground improvement material, and the release of harmful substances. Silicate binder, which is an inorganic matter based on a silicate mineral, includes kaolin, illite and metakaolin. A silicate mineral is made into silicate binder through continuous weathering. Most clay minerals belong to this silicate binder. This study conducted a preliminary study on the strength properties of feldspar powder with high activity. A specimen was made using various silicate material sources such as feldspar, metakaolin, silica fume, illite, dolomite and silica stone. This study analyzed the uniaxial compressive strength according to the type and particle size of silicate binder. The analysis result showed that the uniaxial compressive strength of a specimen using feldspar powder as silicate binder was highest. In particular, the compressive strength of a specimen where silicate powder was added as binder was higher compared to normal cement. This means that feldspar powder with high activity can be utilized as an eco-friendly resource that can replace cement.

Abstract: Vetiver grass is a widespread plant in Thailand. It has been used in several applications such as land erosion prevention, toxic pollutants removal, and environmental remediation. The chemical analysis provided that it mainly contained of >50% of potassium and ~20 wt% silicon. Since, the main element is potassium, then it is likely to be used as feldspar replacement in ceramic processing. The thermal analysis of vetiver grass also revealed that the vetiver grass can act as fluxing agents to form a glassy phase at low temperatures (600°C). The effect of vetiver percentage in ceramic processing on some physical and mechanical properties of ceramics were examined including, firing shrinkage, density, porosity, and bending stress. The results showed that with increasing the ratio of vetiver grass the density of sample decreased from 1.7 g/cm³ (without vetiver grass) to 1.1 g/cm³ (30 wt% of vetiver grass) at 600°C of firing temperature. The explanation was that during the firing process vetiver grass can generate CO₂ from hydrocarbon decomposition, this CO₂ created pores inside the sample, then the density was decreased and pore volume also increased. Meanwhile, the bending stress decreased from 3.6 MPa (without vetiver grass) to 0.5 MPa (30 wt% of vetiver grass) at 600°C of firing temperature. In summary, the results proved that the vetiver grass is a good candidate to be feldspar replacement in ceramic processing. In the other words, it can be one option for promoting environmental sustainability in term of waste and mining reductions.

Abstract: Palm fiber ashes are the industrial waste which is abundantly available in Malaysia. In this study, palm fiber ash were used to produce decorative ceramic glaze. The content of minerals in the palm fiber ash were analyzed by using X-Ray Diffraction (XRD) and X-Ray Fluorescence (XRF), respectively. The formulations of glaze with different composition of raw materials were studied by adding different amount of calcium carbonate and feldspar. The glaze slurries then coated on ball clay body bisque which was obtained from Kg. Dengir and sintered at 1200 ° C for two hours.The glaze was characterized in term of its physical appearance such as type of glaze and colour. Both glossy and matte glaze produced by using different composition of glaze formulation. The presence of silica minerals (79 %) contributed to glossy surface to the glaze. It is clearly seen that the glossiness of glaze improved by increasing amount of feldspar. Feldspar acts as fluxing agent which form a glassy phase at lower temperature. In addition, the presence of small amount of iron oxide (2.2 wt.%) contributed to brown colour of glaze. An addition of calcium carbonate give effect to the colour of glaze, which change from brown to yellow colour as amount of CaCO3 increased. As a conclusion, the palm fibre ashes were highly suitable to supply abundant and cheap raw materials to produce decorative ceramic glaze.

Abstract: Self-diffusion of sodium perpendicular to (001) in a potassium-rich alkali feldspar singlecrystal has been studied by self-diffusion experiments and by Monte Carlo simulations. Sodium diffusivitieswere measured with the radiotracer technique using the 22Na isotope in a temperature intervalfrom 773 K to 1173 K. It was found that self-diffusion coefficients follow a linear Arrhenius relationwith the pre-exponential factor of 1:2 10􀀀3 cm2/s and an activation enthalpy of 1:3 eV. To study correlationeffects in the monoclinic feldspar structure, a Monte Carlo method was applied assuming thatthe two cation species are randomly distributed on the common sublattice and are not influenced by thefixed sublattice of the silicate and aluminate anions. Correlation factors have been calculated assuminga vacancy mechanism and applying a developed four-frequency model for the nearest-neighborvacancy jumps on the alkali sublattice. Our findings strongly indicate that vacancy diffusion providesonly a minor contribution to sodium self-diffusion in potassium-rich feldspars.

Abstract: Porcelain is a traditional ceramic material, which is manufactured for centuries from a mixture of kaolin, quartz sand and feldspar. Another type of porcelain is produces on the basis on bone ash as fluxing agent. Traditional feldspar porcelain and bone porcelain bodies were compared depending on the firing temperature. Two mixtures of kaolin and potassium feldspar or bone ash were prepared. Bone ash is more intensive fluxing agent which need lower sintering temperature (1100 °C) in comparison with feldspar porcelain (1280 °C). Main difference between compared porcelain bodies is in mineralogical composition. Traditional porcelain based on mullite, quartz and glass phase, bone porcelain contains anorthite and β-tricalcium phosphate (β-TCP) and lower content of glassy phase.