Papers by Keyword: Granule

Abstract: The electrolysis of granular matte is a new alternative method for processing sulphide copper materials with the production of cathode copper and the conversion of sulfur to the elemental state. For the first time were established the regularities for the Cu_2-xS – Fe_x+1S granules distribution by the size classes of obtained granulations for the Cu - Fe - S melt at temperatures of 1200, 1250, 1300 and 1350 °C. The maximum amount of Cu_2-xS – Fe_x+1S material of size class 5.0 + 2.5, -2.5 + 1.6 and-1.6 + 1.0 mm, which corresponds to the conditions of following electrochemical processing and estimated as 72.5%, was obtained by granulation of the melt at 1200 °C. The granulometric characteristics of Cu_2-xS – Fe_x+1S granules were estimated. With an increase in the overheating temperature of the Cu - Fe - S melt, granules with a large value of the average diameter were obtained, also the root-mean-square deviation of the particle size from the average value increases and the degree of polydispersity of the granules decreases. The duration of cooling for Cu_2-xS – Fe_x+1S granules from the melt temperatures at 1200, 1250, 1300 and 1350 °C was calculated. In the entire considered temperature range, the particle cooling time is much longer than the spheroidization time, which contributes to the formation of spherical particles.

Abstract: At present, casting and wrought high-strength and light aluminum alloys are widely used in the creation of a number of products and units in mechanical engineering, aviation and space technology. The process of developing alloys includes the formation of initial design data covering the operating conditions, the necessary physical, mechanical and other characteristics of products, and also considers the requirements of manufacturability in their manufacture and ensuring a given structure. To achieve these goals, when smelting aluminum alloys, Al-Mg, Al-Cu, Al-Mn, Al-B, Al-Ti ligatures are used. Despite the widespread use of ligatures, there is no single set of requirements for their quality. However, recent studies in the field of structural heredity in the "charge - melt - cast product" system have shown that the structure of the ligature has a significant hereditary effect on the crystallization process, structure and properties of the modified alloy. In this work, a study of the Al-5Ti-1B master alloy was carried out using synchronous thermal analysis, which made it possible to establish such properties as: the magnitude of the thermal effect, the temperature of its onset, enthalpy, and the crystallization interval. The results obtained make it possible to expand the bank of initial data to improve existing programs for modeling casting processes and to develop new ones.

Abstract: The sintering behaviour of low cost 8 mol% yttria stabilized zirconia powders has been studied. The effect of sintering holding time of the sintered granulated and milled 8YSZ were determined using density measurements, scanning electron microscopy (SEM) and X-ray diffraction (XRD). The elemental composition, particle size and morphology of the as-received 8YSZ powder and proceed for milling was investigated. 48 hours of ball milling on granulated 8YSZ resulted rises in specific surface area and sintered at 1550°C with the various period of time (4, 5, 6 and 7 hours). The milled 8YSZ sample with 5h sintering holding period coded as F5, sintering activity improved and the relative density came up to 98.3%. But then, granulated 8YSZ achieved only 62.7% with 5 hours holding time. Crystal structure analysis for milled 8YSZ powder consists of 59.6% of cubic ZrO₂ phase, 40.1% of tetragonal ZrO₂ and 0.3% of monoclinic ZrO₂. Meanwhile, granulated 8YSZ indicated low content in cubic ZrO₂ but high amount in monoclinic ZrO₂ phase. In brief, low cost 8YSZ reached higher densification of 98% successfully.

Abstract: The injection behavior of β-tricalcium phosphate (Ca₃(PO₄)₂: β-TCP) based cement was improved through the granulation of β-TCP. Dense β-TCP granules were obtained by heat treatment after spray drying. The fraction of injected paste under loaded mass in the syringe was measured while varying the granular fraction of β-TCP and the heat treatment temperature. The increase in granular fraction and heating treatment temperature reduced the amount of setting agent required to wet the granules. As the surplus setting agent could be used in the powdery β-TCP to reduce the viscosity, improved injectability was achieved. Inappropriate setting by the excessive setting agent was not observed and the cements tested exhibited normal setting behavior by forming a brushite phase.

Abstract: The objective in this study focuses oncalcium oxide pellets and granules preparation made from hen eggshellmixed with polysaccharides acted as a binder by wet process. There are many factors effect to size and shape of pellets and granules i.e. types, amount, particle size of binders, viscosityof mixture, and temperature of liquid medium. An important factor is types of binder effect to particle design, nuclei formation, solid-liquid interaction, amount and size of porosity, and pellets/granules dispersion.In this study, all-purpose flour is one kind of polysaccharides and organic binders which is the most suitable for calcium oxide pellets and granules preparation. The average particle, viscosity, amount of starch content of all-purpose flour are equal to 35.9 µm, 1,864 ± 8 cp, 115 ± 1 RVU including non-toxic and less expensive.Furthermore, the chemical composition, particle size, viscosity, and chemical functional groups were measured by using XRF, particle size analyzer, viscometer, and FTIR, and are reported here.

Abstract: The properties of brushite cement were manipulated by partially replacing β-tricalcium phosphate with dense granular hydroxyapatite (HA). The introduction of HA granules resulted in prolonged setting time as well as reduction of temperature rise during setting. The changes produced by addition of HA granule were useful for drug loading. HA granules, prepared by spray drying, could preserve a meaningful 4.5 wt% of gentamicin sulfate solution. However, HA granules with excessive setting agent resulted in formation of dicalcium phosphate instead of brushite.

Abstract: Brushite bone cement containing a drug was prepared using the dense granular β-tricalciump phospahte (β-TCP) as a starting material. The setting reaction was not significantly affected by loading antibiotics within the granules. Heat treatment of the granule at elevated temperature resulted in the suppression of temperature increase during setting, which provided benefits in drug loading. The amount of gentamicin sulfate infiltrated in the β-TCP granules was determined by thermogravimetric analysis and was found to be meaningful considering the MIC of microorganisms.

Abstract: In this research, the fly ash (F/A) discharged from a thermal power plant was recycled to manufacture geopolymer containing granules instead of sand. Several types of granules using fly ash were assessed. The properties of the geopolymer/granule composites were analyzed as a function of the crystalline phase and size of the granules, as well as the molding pressure. The compressive strength and density of the geopolymer composites containing the hydrated granules fabricated by hand-tapping were 5.7 MPa and 1.47 g/cm³, respectively, while composites created by pressure molding were 15.6 MPa and 1.73 g/cm³. These results are comparative or superior to those of commercial cement bricks (8 MPa according to KS F 4004). Therefore, the geopolymer/granule composites fabricated in this study can be applied to cement bricks and can be a base for the enhancement of the recycling rate of fly ash.

Abstract: The purpose of this study was to establish a relationship between the physical properties of powder and its behavior during high shear granulation. Andrographis extract was utilized as a model drug and microcrystalline cellulose (MCC) and soluble starch were selected as excipients. The extract was mixed with different excipient with the ratio 1:0.5, 1:1, 1:2 by weigh, respectively. The granules were prepared by using high shear granulation. The result of HSG was evaluated by monitoring such responses as granule yield, the ratio of Lumps and Fine. The effect of physical properties on granulation behavior was analyzed through stepwise regression. The results showed that angle of repose, moisture content, pore volume, and density were the main factors linked to the granulation. The main physical properties of extract powder were the important factors for high shear granulation, and statistical analysis identified the trends that interpreted in light of physical models of high shear granulation.

Abstract: Hydrogenation is one of the most important transformation reactions widely used in a large variety of areas such as Chemical, pharmaceutical and agricultural industries. Granulated carbon supported palladium catalysts have been used here for hydrogenation of carbon-carbon triple bonds. Catalyst composites and granules were produced by using sodium alginate binder under the certain thermal treatment process. After that, metal salt precursors were deposited using impregnation method. The final catalysts obtained through reduction of metal oxides by hydrazine as reducing agent. After that, metal particles loaded catalysts were utilized to perform hydrogenation reaction. Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) techniques applied for investigation of catalysts. Reaction products were evaluated by High Performance Liquid Chromatography (HPLC) technique. It has been concluded that MWCNT as support exhibits high conversion in the hydrogenation of 2-butyne-1, 4-diol as a typical triple bond carbon-carbon precursor.