Agglomeration Time Research Articles

Investigation of oil agglomeration behaviour of Tuncbilek clean coal and separation of artificial mixture of coal–clay by oil agglomeration

Oil agglomeration technique is one of the several major physicochemical separation processes in fine particle processing. In this study, the oil agglomeration behaviour of Tuncbilek clean coal was investigated and studied to find operating parameters that would decrease the ash content of the clean coal. The optimum conditions for agglomeration time, kerosene concentration and stirring speed were determined to be 20min, 31.6wt.%, and 1500rpm, respectively. Also, the ash content of the coal could be decreased by the addition of methanol.The separation of various artificial mixtures of coal–clay samples was also investigated under the determined optimum conditions. The coal could be agglomerated with above 80% of combustible recovery. The ash content was nearly the same for all conditions and determined to be approximately 6%. The coal was separated from clay minerals with high combustible recovery and low ash content using selective oil agglomeration technique.

Optimization studies on coal–oil agglomeration using Taguchi (L16) experimental design

Coal–oil agglomeration has been a prominent fine coal processing technique, which involves agitation of coal–water slurries in presence of immiscible oil forming coal–oil agglomerates. The present study investigates this technique using Taguchi (L16) design of experiments (DoE) methodology. Further, the process parameters like oil dosage, agitation speed, agglomeration time, pH and temperature were optimized using Analysis of Mean (ANOM) statistical approach and the percentage contribution of each of these parameters towards organic matter recovery (OMR) was determined by Analysis of Variance (ANOVA) statistical approach.The optimum conditions for maximum OMR (91.38%) were identified as oil dosage of 30%, agitation speed of 2500rpm, agglomeration time of 2min, pH of 12 and temperature of 30°C. The contribution of each of the above process parameters towards the OMR was found to be in the following order: pH (30.38%)>agitation speed (23.06%)>oil dosage (20.63%)>agglomeration time (13.72%)>temperature (10.61%). Multiple linear regression analysis carried out using SPSS 19.0 ascertained a similar order of influence on the OMR. The highest contribution of suspension pH further establishes the fact that oil agglomeration process is a surface property based technique, as pH affects the surface charge on coal/mineral matter/oil droplets. A mathematical model was also developed using SPSS 19.0 to predict the OMR by oil agglomeration under the given set of experimental conditions. The developed model could predict the OMR to a significant extent, which can be further improved by a DoE technique of higher order.

Oil Agglomeration of Coal Fines in Continuous Mode of Operation

Coal–oil agglomeration plays a vital role in addressing the ever increasing pollution due to coal utilization apart from minimizing coal-waste generation. Numerous studies were available on coal–oil agglomeration in batch mode; however, the process has been seldom investigated under continuous mode of operation. In the present study, an attempt has been made to examine the coal–oil agglomeration process under continuous mode of operation using high ash power grade coal procured from Jharkhand (India) with Karanja oil as agglomerant. The effectiveness of the process was estimated in terms of organic matter recovery (OMR) and ash rejection (AR). Preliminary experiments were performed under batch mode to optimize the process variables (oil dosage, agitation speed, agglomeration time, and coal particle size). Subsequently, the process was operated in continuous mode under these optimum conditions by varying the reactor residence time. In batch mode, a maximum OMR (78.09%) with significant AR (51.28%) was observed under the following optimized conditions: oil dosage (20% by wt of coal); agitation speed (1,500 rpm); agglomeration time (120 s); and coal particle size (+75–200 µm). However, operation under continuous mode resulted in lower OMR (maximum 47.51%) with higher AR (70.38%), which can be attributed to inadequate contact between coal fines and oil.

Development of Lemon Fruit Flavored Tasty Saline Functional Powder Drinks

Nowadays, agglomerated citrus fruit flavored Tasty Saline functional powder drink represents a very appealing functional beverage for adult customers. It is produced by mixing basic ingredients (refined sucrose, refined common salt, encapsulated lemon flavor, dextrose anhydrous and potassium chloride) which were followed by agglomeration. Agglomeration is necessary, because non-agglomerated refined sucrose exhibit very poor flow and reconstitution properties. This research showed the influence of process conditions and composition of the different powder mixtures on the physical properties of the agglomerated final product. Agglomeration was conducted using batch fluid bed agglomerator at a constant air temperature (60°C), with a constant addition of citric acid with acid regulators with varying duration of the process and varying amount of added water. Bulk density and particle size were conducted prior to and post agglomeration, while agglomerate hardness was estimated by conducting a compression test with a 30 mm probe on Texture Analyzer. Percentage of added water had a significant effect on bulk density and the duration of the agglomeration process. This effect was more significant with mixtures made with salt. As for mixtures with 0.45 % to 0.55% encapsulated flavor, a significant influence of water addition on agglomerate median diameter was found. Agglomeration time and the percentage of added water showed dependence towards the composition of the mixture. This research showed that, in order to agglomerate powder mixtures successfully, parameters such as mixture composition, particle size, percentage of added water and acidulates, drying temperature, process duration and ambient conditions should be well coordinated and controlled to get agglomerates with optimal quality.

The Process Research on VN-Making which Deploy Vanadium Pentoxide Powder, Graphite and Carbon Black in the Lab

This paragraph deploys high temperature non-vacuum methods, and vanadium pentoxide powder, carbon black and graphite is used to make VN. The result shows that the particle sizes of these three raw materials vary greatly. When they are mixed with a certain proportion, the kinetics condition of reaction is greatly improved. when the vanadium pentoxide powder enters agglomeration level(1490°C) after it has been reduced and nitrided, agglomeration time has small effect on the reaction process and chemical composition of product. On the contrary，if the agglomeration time lasts too long, it will generate VC. Therefore, the agglomeration time can be reduced to 2~4 hours.

Comprehensive study of process parameters affecting oil agglomeration using vegetable oils

Spherical agglomeration is a size enlargement process in which the disperse medium is held together in aggregates by liquid bridges of an immiscible agglomerating agent in the dispersion medium in general, an aqueous environment. Extensive studies on the process have shown that the process is affected by a number of process parameters. In the present paper, a large number of process parameters such as agitation speed, oil dosage, agglomeration time, coal particle size, slurry pulp density, pH and temperature of the dispersion medium, oil type, surfactant (anionic) use, and sea water usage as pulping medium. affecting the oil agglomeration of Indian bituminous coal procured from North-Eastern region of the country were investigated. Initially, the process parameters were optimized for maximum coal recovery with significant ash rejections. Subsequent experiments to study the effect of surfactant, oil type and sea water usage as pulping medium were performed under the optimized conditions. All the experiments were performed under batch mode of operation. The coal–oil agglomerates were recovered by screening using a standard test sieve whose pore size was same as the maximum size of feed coal particle. The overall agglomeration performance was studied in terms of efficiency index which took into account both combustible recovery and ash rejection, the two important process estimates of the agglomeration process. The experimental results showed that the Indian bituminous coal used in the study was quite receptive to oil agglomeration process and significant recovery of coal fines with considerable ash rejections was possible through this clean coal technology.

The Selective Oil Agglomeration of Combustibles in Fines of Low Grade Lignite of Barmer Rajasthan (India)

Oil agglomeration is one of the more effective methods for recovering and reducing ash of lignite fines. The effects of some parameters that markedly influence the effectiveness of selective oil agglomeration, such as solid concentration, amount of agglomeration oil, agglomeration time, and effect of various hydrocarbon oils were systematically studied. The sample of Giral Lignite Mines of RSSM in Barmer district was agglomerated with different hydrocarbon oils, such as toluene, diesel, and pine oil. The calorific value of the lignite sample has been recovered to 2,190 kcal/kg from 1,687 kcal/kg and reduced ash from 35.50 to 28.47%.

Gold Nanocluster Agglomeration Kinetic Studies: Evidence for Parallel Bimolecular Plus Autocatalytic Agglomeration Pathways as a Mechanism-Based Alternative to an Avrami-Based Analysis

The most extensive and highest quality Au0n nanocluster agglomeration size vs time TEM data set yet obtained are analyzed by a nanoparticle size vs time equation that is derived herein for parallel bimolecular (B + B → C, rate constant k3) and autocatalytic (B + C → 1.5C, rate constant k4) agglomeration steps of preformed nanoclusters, B. The results show that the size vs time data are well fit by the new size vs time equation. The fits and resultant k3 and k4 rate constants yield several interesting insights that are presented and discussed, including the finding that to date k4 > k3, that is, that the autocatalytic agglomeration rate constant is faster than the bimolecular rate constant, at least for the cases examined to date. The results of the effects of added TOABr (tetraoctylammonium bromide) on the 180 °C agglomeration k3 and k4 rate constants in unstirred diphenylmethane solvent are also presented and discussed, the TOABr being added originally to compact the nanoclusters double layer thereby helping induce agglomeration. The observed different [TOABr] effects on k3 vs k4 also provide prima facie evidence that the two agglomeration steps are fundamentally different and unique. Literature size vs time data, from El-Sayed et al. for Pd nanocluster agglomeration, are also fit as a further test of the new, mechanism-based size vs time equation. The combined results, showing good fits by the k3 and k4 steps to the Au0n as well as literature Pd, Pt, and Ir nanocluster data, provide good support for the underlying B + B → C and B + C → 1.5C agglomeration steps themselves as well as for the assumptions and math behind the new size vs time equation. The significance of the results in general, as well as for future measurements of k3 and k4 rate constants as a preferred way to quantitate nanocluster stability in solution, are also presented and discussed. Most significant, however, is that as a result of the present work one can now use chemical equations and associated, mechanistically rigorously defined concepts of bimolecular (B + B → C; rate constant k3) and autocatalytic (B+ C → 1.5C; rate constant k4) agglomeration to analyze and describe nanoparticle agglomeration rather than the harder to interpret, more obscure n and k parameters from an Avrami-type, semiempirical curve fit.

Agglomeration kinetics of submicron barium sulfate precipitates

Unwanted agglomeration, especially in highly concentrated submicron and nano- particle suspensions, can rapidly change the physical product properties of produced particles. Knowledge of the agglomeration kinetics and mechanisms is crucial to achieve control over this secondary sub-process of particle formation.To obtain this kinetics a new measurement method is presented to monitor the shear induced agglomeration behavior of submicron barium sulfate particles while passing a narrow pipe. The residence time, i.e. agglomeration time was varied with the pipe length at constant suspension flow rate. Before measurement, the particle suspension was stabilized by rapid mixing with a dispersing agent. Based on measured agglomerate size distribution, the agglomeration behavior is discussed in terms of non-turbulent flow in a narrow pipe.Barium sulfate agglomeration in a simple shear flow could be monitored on submicron scale. The effect of steric stabilization to reduce or prevent agglomeration was shown and quantified. The controlling mechanism for agglomeration in a pipe is identified based on the hydrodynamic characteristics. The adhesion probability was found to decrease with agglomerate size.

Controlled Synthesis of Single-Walled Carbon Nanotubes in an Aerosol Reactor

The growth mechanism and influence of synthesis parameters on the properties of single-walled carbon nanotubes (SWNTs) produced by ferrocene vapor decomposition in a carbon monoxide atmosphere have been investigated in detail by a combined study of Raman and UV−vis−NIR absorption spectroscopy and transmission electron microscopy (TEM). CO2 plays an essential role in selective etching of small diameter nanotubes and the purification of SWNTs. This etching effect is beneficial to narrow the diameter distribution and to control the average diameter of SWNTs. Increasing the synthesis temperature results in the formation of larger catalyst particles due to a higher agglomeration rate, thereby forming larger diameter nanotubes. Decreasing the CO flow rate, and thus lengthening the agglomeration time, also provides the possibility to enlarge the diameter of SWNTs. Therefore, by varying the growth parameters, the mean diameter of SWNTs can be effectively changed from 1.2 to 1.8 nm to satisfy the needs of various applications.

Numerical simulation of standing waves for ultrasonic purification of magnesium alloy melt

It was attempted to enhance and accelerate the separation of oxidation inclusions from magnesium alloy melt by virtue of ultrasonic agglomeration technology. In order to investigate the feasibility and effectiveness of standing waves for ultrasonic purification of magnesium alloy melt, numerical simulation and relevant experiment were carried out. The numerical simulation was broken into two main aspects. On one hand, the ultrasonic field propagations within the cells with various shapes were characterized by numerical solutions of the wave equation and with a careful choice of geometry a nearly idealized standing wave field was finally obtained. On the other hand, within such a standing wave field the agglomeration behavior of oxidation inclusions in magnesium alloy melt was analyzed and discussed. The agglomeration time and agglomeration position of oxidation inclusions were predicted with numerical simulation method. The results show that the oxidation inclusions whose apparent densities are close to the density of the melt can agglomerate at wave nodes in a short time which to a great extent enhances and accelerates the separation of oxidation inclusions from magnesium alloy melt.

Optimization of experimental conditions for recovery of coking coal fines by oil agglomeration technique

The significance of coking coal in the metallurgical sector as well as the meager coking coal reserves across the globe increase the necessity to recover coking coal fines from the fine coking coal slurries generated from coal preparation and utilization activities. Oil agglomeration studies were carried out by varying the experimental conditions for maximum recovery of coking coal fines i.e., yield of the agglomerates. The various operational parameters studied were oil dosage, agitation speed, agglomeration time and pulp density. By using Taguchi experimental design, oil dosage (20%), agitation speed (1100 rpm), agglomeration time (3 min) and pulp density (4.5%) were identified as the optimized conditions. A confirmation experiment has also been carried out at the optimized conditions. The percentage contribution of each parameter on agglomerate yield was analyzed by adopting analysis of variance (ANOVA) statistical method as well as multiple linear regression analysis. The order of influence of the parameters on the agglomerate yield is of the following order: pulp density > oil dosage > agitation speed > agglomeration time. A mathematical model was developed to fit the set of experimental conditions with the yield obtained at each test run and also at the optimized conditions. The experimentally obtained yield was compared with the predicted yield of the model and the results indicate a maximum error of 5% between the two. A maximum yield of 90.42% predicted at the optimized conditions appeared to be in close agreement with the experimental yield thus indicating the accuracy of the model in predicting the results.

Amenability of Muzret bituminous coal to oil agglomeration

Laboratory scale agglomeration tests were undertaken to investigate the amenability of Muzret (Yusufeli-Artvin) bituminous coal to oil agglomeration. Kerosene was extensively used as oil in the tests. In addition, fuel oil, diesel oil, and hazelnut oil were also used in order to determine the effect of oil type. The effects of the parameters including coal content, kerosene content, agglomeration time, coal particle size, pH, oil type, and agitation rate, on the combustible matter recovery, ash reduction and pyritic sulphur reduction, were investigated. It was found that Muzret bituminous coal could be readily cleaned by oil agglomeration with substantial reductions in ash and pyritic sulphur content. Maximum combustible matter recovery, ash reduction and pyritic sulphur reduction were achieved to be 85.54%, 59.98%, and 85.17%, respectively.

In line monitoring of wet agglomeration of wheat flour using near infrared spectroscopy

The aim of this work was to investigate the ability of the NIR spectroscopy method to describe the physical and chemical changes occurring during wet agglomeration of wheat flour. The NIR spectra were analysed as raw spectra and after second derivative treatment by using principal components analysis (PCA). The results are discussed in terms of physical and chemical changes involved in wet agglomeration. The results confirm the ability of NIR spectroscopy to identify the wet agglomeration time of wheat flour (time necessary to obtain an homogenous distribution of particle size) and the possibility to propose physical and chemical analysis of NIR spectra. The spectra show that the most important physical and chemical modifications occurring during crumbly dough mixing are associated to the modifications of the glutenin depolymerisation, flour particle hydration and changes in particle size.

Kinetics of NiSi-to-NiSi 2 transformation and morphological evolution in nickel silicide thin films on Si(0 0 1)

We have investigated the kinetics of the NiSi-to-NiSi 2 transformation by monitoring the phases present in nickel silicide films after various annealing treatments. It has been found that, for very short annealing times, essentially pure NiSi films can be retained on Si(0 0 1) at temperatures up to 800 °C, a temperature significantly higher than that normally observed (∼700 °C) for the NiSi-to-NiSi 2 transformation. A time–temperature transformation diagram was constructed to elucidate the kinetics of the NiSi-to-NiSi 2 transformation, which was explained in terms of the classical theories of nucleation and growth. It was also found that, at a given temperature, agglomeration of NiSi films can be avoided by using short annealing times. The activation energy for grain growth in NiSi films was estimated using a concept of “agglomeration time”.

FLOW AND TEMPERATURE DEPENDENCE OF PARTICLE FORMATION IN AR-SILANE RF CAPACITIVELY COUPLED PLASMAS

In this work we present an overview of our investigations on the particle formation in Silane plasma. We propose a generalized model, based on a simple balance equation, explaining the temperature and flow dependence of the agglomeration time of nano-clusters in Ar-SiH4 plasmas. This model allows easy incorporation of specific mechanisms and verification of their effect on particle growth.

Temperature Dependence and Silane Consumption During Particle Formation in Ar–Silane RF Capacitively Coupled Plasma

We propose a generalized model, based on a simple balance equation, explaining the temperature dependence of the agglomeration time of nanoclusters in Ar-SiH/sub 4/ plasmas. This model allows easy incorporation of specific mechanisms and verification of their effect on particle growth. We consider extra silane consumption due to back diffusion, an important issue for the laboratory plasma experiments and modeling results interpretation.

Morphological evolution of thin gold films studied by Auger electron spectroscopy in beading conditions

The evolution of thin gold films deposited on a sapphire surface was studied in UHV using Auger electron spectroscopy and atomic force microscopy techniques. The annealing temperatures were in the range 573–843 K. Starting from a continuous film, we observed at the end of the process a collection of beads. The incubation time in this temperature range was negligible, while the agglomeration time varied from about 2 h at 573 K to a few minutes at 843 K. The kinetics of metal agglomeration allowed the evaluation of the surface self diffusion coefficients of gold which can be expressed by

Investigation of spherical oil agglomeration properties of celestite

In this study, concentration of celestite particles was investigated by using oil agglomeration. For this purpose, effects of operating parameters were investigated, and zeta potential measurements and Fourier transform infrared spectrophotometry (FTIR) analyses have also been carried out. In the experiments, effects of operating parameters such as pH, stirring speed, amount of Na oleate as a anionic type collector and kerosene as a bridging liquid, solid ratio, agglomeration time, collector stirring time, conditioning time, and amount of EDTA were investigated to obtain optimum conditions. Zeta potential measurements were carried out for various pH values and amounts of Na oleate. FTIR analyses were investigated to determine the adsorption type of Na oleate on celestite surface. By evaluation of the experimental results, optimum oil agglomeration conditions of celestite were determined as follows: pH 7, stirring speed 1500 rpm, amount of kerosene 100 l/t, amount of Na oleate 10 kg/t, solid ratio 5 wt%, conditioning time 5 min, collector stirring time 1 min, agglomeration time 5 min, and amount of EDTA 1.0 kg/t. In the optimum conditions, celestite was concentrated with recovery of 89.47 wt%.

Particle drift in a resonance tube--a numerical study.

The paper considers longitudinal drift of small particles in a resonance tube, caused by periodic shock waves, and its effect on particle agglomeration. It is found that depending on particle size, drift is caused by shock waves and/or gas acceleration and compression. It is also shown that the drift velocity and direction can be controlled by the frequency of the piston that causes gas oscillations in the resonance tube. The obtained numerical solutions indicate that particle drift in a resonance tube enhances aerosol agglomeration. An agglomeration kernel is derived for this case, accounting for particle drift, leading to an estimate of agglomeration time. The time predicted by present model is of the same order of magnitude as that obtained from experiments in the literature.