Papers by Keyword: Agglomeration

Abstract: This scientific study presents experimental results of particle agglomeration and dispersing processes under various physicochemical conditions, focusing on the effects of temperature, particle concentration, and medium viscosity. Using numerical approaches and experimental data, patterns describing the changes in agglomeration rate and the features of dispersing system stability were identified. The key findings of the research include: the influence of temperature on agglomeration, high particle concentration, medium viscosity, dispersion under low particle concentration conditions. It is noteworthy that the results also confirm an exponential dependence of the agglomeration rate on temperature. However, at high particle concentrations, this effect is mitigated by the dominance of interparticle interactions, such as Van der Waals forces and electrostatic effects. Furthermore, in systems with low particle concentration and elevated temperature, agglomeration processes significantly slow down, indicating improved dispersing stability. The study opens new perspectives for controlling particle agglomeration and dispersing based on temperature, concentration, and the physical properties of the medium. The obtained data can be useful for improving existing technologies and developing new ones in areas where controlling the behavior of dispersed systems is essential.

Abstract: Transition metal ion was added to CMP (chemical-mechanical polishing) slurry without abrasive particle to solve the problem of CMP. MRR (material removal rate) value of SiC substrate processed using non-abrasive slurry was comparable to MRR values of SiC substrates using abrasive slurries. The scratch formation was successfully suppressed in SiC substrate polished with using non-abrasive slurry and no residual particle resulting from agglomeration of abrasive particles could suppress scratches and forms a good quality of SiC substrate surface. Uniform and high-quality SiC substrates could be prepared through the non-abrasive CMP process.

Abstract: Hollow graphitic porous carbon nanosphere (CNS) materials are synthesized from polymerization of resorcinol (R) and formaldehyde (F) in the presence of templating iron polymeric complex (IPC), followed by carbonization treatment. The effect of rapid heating in the carbonization process is investigated for the formation of hollow graphitic carbon nanospheres. The resulting CNS from rapid heating was characterized for its structure and properties by transmission electron microscope (TEM), x-ray diffraction (XRD), Raman spectroscopy, bulk conductivity measurement and Brunauer-Emmett-Teller (BET) surface area. Hollow graphitic CNS with reduced degree of agglomeration is observed under rapid heating during the carbonization process when compared to the CNS synthesized using the standard slow heating approach. Key words: carbon nanosphere (CNS), rapid pyrolytic carbonization, agglomeration

Abstract: The objective of this research is to study the effect of water content on particle characterization and agglomeration of bamboo charcoal resulted from ball milling process. The characterization is determined by the particle size and the morphology of the particle. The milling was performed in cylinder vial of stainless steel. The element of milling is steel balls. The dimension of the cylinder vial was 120 mm length and 1-inch diameter, while the ball diameter was 5/32 inch. The charcoal resulted from pyrolysis was milled manually then strained with a filter size of 200 meshes. The particles passing the strainer were washed in water and then dried to obtain 25%, 28%, 32% and 35% water content. Then they were put together with the milling balls into cylinder vial. There were four vials with a water content of 25%, 28%, 32% and 35% respectively for milling process. Every vial contained 11 grams of bamboo charcoal and approximately 299 grams of steel balls. It represents 1/3 of vial volume for charcoal, 1/3 of vial volume for ball and 1/3 of vial volume for empty space. Two type tests were conducted. The first test was to run the milling machine at 700 rpm for 2 million cycles and the second test was to run the milling machine at 1000 rpm for 3 million cycles. Particulate characterization was done by a particle size analyzer (PSA), a scanning electron microscope (SEM) with energy dispersive X-Ray (EDX). The results showed that the water content does not have any influenced to the particle size. For the both test the particle sizes are in the range of 100 nm or less to more than 1 μm. However, the second test produces smaller particles and a higher number of smaller particles due to higher impact energy and longer milling time. The two tests inform that agglomeration does not happen by having wet milling. The dominant element of the bamboo charcoal is carbon with more than 90% in number.

Abstract: The present work relates to hydrometallurgy, in particular, to gold-bearing clay ores leaching processes. The initial and agglomerated material filterability was studied. Filterability varies in different agglomeration conditions. Influence of cement, lignosulfonate, plastizer (Cemmix CemPlast), lime consumption was investigated. The negative effect of organic reagents additives, such as plasticizer (Cemmix CemPlast) and lignosulfonate, on the filtration process was established. Colmatation of agglomerated ore minimizes at CaO and Ca (OH)2 using as a modifier of the system, also phase separation in the percolation regime and under pressure proceeds without difficulty. Lime and cement joint use in the optimum proportion at clay ore agglomeration under the studied conditions reduces the filtration duration from a few hours to 2-5 minutes.

Abstract: The article provides an overview of the argillites raw material of Russia. It describes chemical and mineralogical characteristics of argillites and their main properties. It indicates that argillites chemistry has some peculiarities like high content of A₂O₃ – from 17 to 23 %, К₂О – from 2,5 to 4,3 % and iron oxides from 4 to 7 %. Mineralogy of argillites includes two types of hydra micas: an isometric one being allothigenous constituent and a bladed one being the transformation product of montmorillonite underwent catageneses. Also argillites always contain kaolinite, chlorite, glauconite, quartz, plagioclase. The article contains the main requirements for paving clinker and ceramic tile and major trends of their production. Information about dependence of the effect of argillites reduction ratio and firing temperature on strength, absorption capacity and density of the samples is provided. Influence of their interconnected nature on the properties of the product is described. It is specified that due to finer argillites reduction in the size range of 0-0.16 – 0-1.25 mm, the samples strength increases 1.5-2.5 times. Higher firing temperature in the range from 900 to 1100 °C allows increasing strength 2-4 times. In given intervals of reduction ratio and firing temperature the index of water absorption capacity of less than 5 % needed for ceramic tile is achieved by size reduction of 0 – 0.315 mm and firing temperature of 1000 °C and higher. The water absorption capacity of less than 2.5 % needed for paving clinker is achieved by size reduction of 0 - 0.315 mm and firing temperature of 1050 °C and higher. Rationale for production perspectiveness of paving clinker and ceramic tile of low-temperature sintering based on argillites is provided.

Abstract: This paper addresses the complicated process of carbon dioxide particle formation (agglomeration), which is essential for carbon dioxide snow blasting. Most effective process methods in this field possess a dedicated location where agglomeration is likely to occur. Research has shown that successful agglomeration is a key factor when cleaning or deburring with solid carbon dioxide. The following describes the mechanisms of carbon dioxide (CO₂) snow agglomeration inside this so-called agglomeration chamber. The elements of larger size, as well as an irregular shape directly lead to the increase of effectiveness. Therefore, it is necessary to determine how to improve this process for the purpose of dealing with difficult workpieces and materials and broaden the possibilities of carbon dioxide blasting. One of the main factors of agglomeration is turbulence. In short, the more turbulent activity that takes place, the better is the particle formation of solid carbon dioxide. Numerous geometries were created with different inserts, such as static mixers or angled tubes, in hope to increase turbulence. The basic idea is to implement these geometries in computational fluid dynamics (CFD) and finally proceed to an evaluation and comparison of the simulation results, in order to select the best candidates for optimization and realization.

Abstract: Under laboratory conditions, the method of mathematical planning of experiments was used to study the effect of charge fractional composition (in the range of 2 to 8 mm) and the amount of coke in the charge (in the range of 7 to 13 wt.%) on the agglomeration process characteristics of the “Mamatwan” manganese ore (South Africa). It was found that the main agglomeration parameters vary within the following limits: the initial vacuum under grate – 54...140 mm WC for the charge layer of 350 mm; the maximum temperature – 1365...1440 °С; linear burning speed – 13,4...26,2 mm/min; the charge length of stay at temperatures over 1300 °С (the width of the melting zone) – 2,4...4,8 minutes. Mathematical equations of the combined effect of charge fractional composition and the amount of coke on agglomeration temperature, linear burning speed, width of melting zone (in time), initial vacuum in reactor were calculated. It was found that a major factor in providing the optimum mode of agglomeration is not the amount of coke, but the charge piece size distribution. For example, increasing the charge piece size has an 3,5 times more effective influence on the agglomeration temperature than the amount of coke. For the dust-containing charges the moistening up to 4...6 wt.% H₂O is only partially solves the problem of the aerodynamic resistance. Pre-granulation of the dust fraction is needed to improve the gas permeability of the charge.

Abstract: Free Ti/Si/C powder mixtures with or without molten salt were heated under vacuum with various schedules. The effect of molten salt during synthesis on the morphology and phase composition of Ti₃SiC₂ powders were investigated. The combustion powders were analyzed by DSC, XRD, SEM and EDS. The results indicated that the existence of molten salt could promote the reaction process and decrease the synthesis temperature. The Ti₃SiC₂ powders obtained by molten salt method were uniform and well dispersive. The content of Ti₃SiC₂ phase was influenced by salt/powders ratio and molding pressure. The appropriate salt/powders ratio and pre-press pressure were 1:1and 100 MPa, respectively.

Abstract: In automobile application, suspensions are used for various purposes. To improve the stability and to withstand maximum load we are trying to add additional source which is called suspension. These suspensions are made attached along with the ordinary suspension. This is manufactured using magnetic fluid called ferrofluid. Here the complete preparation of ferrofluid was done and their characteristics were studied. In this, the experimental setup of suspension has been studied and working was analyzed. The fluid was prepared and compared the viscosity with ordinary fork oil. This liquid substance which acts as a source of suspension, which has maximum efficiency when compared to ordinary fluid. These can be varied to different shapes depending on the application and needs.