Papers by Keyword: Barium Carbonate

Abstract: Portland clinker is thanks to its large-scale production a continuously studied topic. Clinker, or Portland cement, is used for construction purposes or for insulation and special applications. One of these special applications could be shielding of different types of radiation by making use of the content of barium ions. The present article examines the influence of barium oxide on the formation and properties of Portland clinker, which could be, by incorporation of barium ions into the system, used as a binder for buildings resistant to various types of radiation. Barium sulphate and barium carbonate were added to the raw meal in order to prepare clinkers with different content of barium oxide. The effect of barium on the formation of clinker phases was studied (by XRD – Rietveld analysis and by the microscopic point counting method), as well as the rate of alite formation under isothermal conditions. Furthermore, the ability of barium to become a part of clinker minerals was studied by SEM with EDS.

Abstract: For ceramic industry, efflorescence is undesirable and cannot be completely eliminated from the finished products. The efflorescence is caused by soluble salts in the raw material and mostly appears as white deposit at the product’s surface. In this research, the removal of sulfate in the raw materials was studied. In addition, the sulfate ions were immobilized by forming a water-insoluble compound. The sulfate ions in the raw materials and fired products were extracted by distilled water, and the concentration was determined by using a UV-visible spectroscopy following the ASTM C1580-09 standard. Three sources of the raw materials from Tambon Suan Phung, Ratchaburi, Tambon Mae Win and Mae Ta, Chiang Mai, were analyzed for sulfate concentrations. The clay from Tambon Suan Phung, Ratchaburi which had the highest sulfate concentration was selected for further study on the effect of inhibitor and firing temperature on efflorescence inhibition. To reduce solubility of the sulfate, three kinds of inhibitor, i.e. barium chloride, barium carbonate and barium hydroxide, were added into the raw material at various concentrations, i.e. 0.5, 1.0, 1.5 and 2.0 wt% and homogeneously mixed by ball milling followed by the addition of distilled water to prepare the clay slip. The clay products were mold casted to 1 x 1 x 3 inch³ in size. Then, they were fired at 800, 900 and 1000 °C. It has been revealed that the addition of barium carbonate at 2 wt%, which is the highest amount employed in this study, and firing temperature of 900 °C resulted in least sulfate leaching due to the formation of water-insoluble barium sulfate. To perform a field test, the fired samples with and without the addition of barium carbonate were immersed in water for 4 months. The efflorescence was observed on the sample without barium carbonate within the 1^st month. In contrast, with the addition of barium carbonate, no efflorescence was observed after testing for 4 months.

Abstract: New iron-based composite materials with addition of barium carbonate (2 to 8 wt% barium carbonate) for friction applications are investigated. The tribological behavior of the studied materials was determined by a pin-on-disk method when a cast iron disk was employed. The addition of 2 wt% barium carbonate determined a significant increase of the average friction coefficient. Instead a further increase of barium carbonate content determined a gradual decrease of this parameter. The improvement of wear resistance was marked out for a barium carbonate content of up to 6 wt%. The optimal ratio between the average friction coefficient and the wear rate for the researched Fe-Cu-graphite-Ni-BaCO₃ composites was determined for the iron-based material containing 2 wt% barium carbonate. SEM, EDX and XRD analysis marked out a complex structure containing alloyed ferrite, pearlite and carbides, traces of nickel and barium carbonate and free graphite.

Abstract: With calcium carbonate and barium carbonate as desulfurizers, combustion desulphurization experiments of coal water slurry and pulverized coal were respectively done in the ZCL. The results show that desulfurization efficiency in coal water slurry is prior to the same pulverized coal. The desulfurization characteristic of desulphurizing coal water slurry was analyzed by comparing the desulfurization efficiency of coal water slurry and pulverized coal. The reaction atmosphere in the boiler is different from the pulverized coal because of water evaporation ,and the CO content was lower ,so the decomposing rate for desulphurization products was reduced,after water evaporated ,it formed microstructures which was considered as favorable to the desulfurization rate .

Abstract: This paper focused in details about dielectric properties of BT with different stoichiometry. In this research, BT was synthesis by solid state reaction between TiO₂ and BaCO₃ at constant sintering temperature of 1350 °C. Five different ratio of BT was characterized by using SEM, XRD, and IS. There have production of secondary phase when Ba was excessive. Impedance plot shows the relation between dielectric properties and stoichiometry of BT where the highest value of dielectric properties is comes from sample with Ba/Ti ratio equal of 1:1.

Abstract: This paper focus on the effect of different ratio between barium (Ba) and titanium (Ti) to the production of high purity of barium titanate (BT). On this research, the sample was prepared by solid-state reaction between barium carbonate (BaCO₃) and titanium dioxide (TiO₂) powder at constant sintering temperature of 1350 °C. The sample was prepared at different ratio of Ba:Ti which are 1:0.9, 1:0.95, 1:1, 1:1.05, 1:1.1. All sintered BT was characterized by X-ray diffraction (XRD). All existed phase on these samples was determined and analyzed. Sample from ratio 1:1 produced almost a single phase of BT. While; samples from other ratio produce secondary phase which is barium orthotitanate (Ba₂TiO₄).

Abstract: Ecological crystal glass with no toxic compounds, especially lead, was based on soda-lime-silica glass that fabricated mainly from 50 wt% local dressing sand, 22 wt% barium carbonate and doped with various concentrations of zirconium dioxide. Density (ρ), refractive index (RI), thermal expansion coefficient (CoE) and hardness (HV) were measured. It was found that the values of ρ, RI and HV increased linearly as the increasing of zirconium dioxide contents, whereas the CoE was decreased. This type of glass was ecologically friendly material.