scholarly journals Optimium conditions for the production of sub-micron cobalt power

2015 ◽  
Author(s):  
◽  
Andricia Hareepersad
Keyword(s):  
Particle Size ◽  
Response Surface Methodology ◽  
Particle Size Distribution ◽  
Design Of Experiments ◽  
Response Surface ◽  
Size Distribution ◽  
Process Conditions ◽  
Cobalt Powder ◽  
Optimal Response ◽  
Factor Design

Cobalt powder is a grey metallic powder that is produced by the thermal decomposition and reduction of a cobalt compound. The challenge faced by Shu Powders Africa was that sub-micron cobalt powder had never been produced in a two-step furnace by any manufacturer in the cobalt powder industry. Hence there was no prior information to guide this type of processing. Therefore this research set out to investigate the production of sub-micron cobalt powder through a two-step furnace to determine the optimum parameters for this process. For the company to remain competitive, it was imperative to begin producing sub-micron cobalt powder. Sub-micron cobalt powder is much more valuable and profitable to produce. The second production line would be operational due to the production of sub-micron cobalt powder hence creating job opportunities for the local community. Sub-micron cobalt powder shares the same chemical composition and physical characteristics as cobalt powder. The only differences are particle size (0.60 - 0.90 µm), oxygen content (0.30 - 0.80%) and the microscopic structure which is the particle size distribution d90 (7 - 10 µm). The approach taken was to understand the variables that had a large effect on the powder. The effects needed to be established by determining how it impacted on the quality of the powder which is pertinent to making sub-micron cobalt powder. Due to the experience in producing cobalt powder, variables that had a large effect on normal cobalt powder production were assumed to be the same variables that would impact the production of sub-micron cobalt powder. Some of these effects were also confirmed by literature. A strategy of statistical design of experiments was used to evaluate the conditions for sub-micron cobalt powder production. Design of experiments assisted in planning the experimental design matrices for both experiments. For the furnace experimentation a 24 factor design was selected. For the jet mill experimentation a 23 factor design was selected. Response surface methodology was used to determine optimum ranges of the variables at various process conditions. The central composite rotatable design laid out the design in which the variables interacted with one another at different process conditions. Evaluation of results was based on the generated model. Models such as the 3D surface model, cubic model and the contour model were generated to graphically illustrate the effects that the variables have on the response. Analysis of furnace data indicated that the optimal response was achieved at a temperature range (445 - 460)°C, hydrogen gas range (225 - 250) Nm3/h, belt speed (80 - 90) mm/min, and carbon dioxide gas range (80 - 90) Nm3/h. Analysis of the jet mill experimental data indicated that the optimal response particle size distribution, was achieved at a classifier speed range of (5500 - 6000) rpm, AFG grinding bin range (30 - 35) kgs and grinding gas pressure of (4.0 - 4.5) bar. The study confirms the efficiency of a two-step furnace to produce sub-micron cobalt powder at high volumes. The advantage of the two-step furnace was the increased throughput of 2.3-2.7 tons/day whilst in industry furnace throughputs are 1.3-1.6 tons/day. This represented a 60% increase in productivity over conventional furnaces. The response surface methodology also proved to be a suitable technique for process optimization.

scholarly journals Numerical Simulations of Molten Breakup Behaviors of a de Laval-Type Nozzle, and the Effects of Atomization Parameters on Particle Size Distribution

Processes ◽  
2020 ◽  
Vol 8 (9) ◽  
pp. 1027
Author(s):  
Lianghui Xu ◽  
Xianglin Zhou ◽  
Jinghao Li ◽  
Yunfei Hu ◽  
Hang Qi ◽  
...  
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Gas Flow ◽  
Nozzle Geometry ◽  
Particle Model ◽  
Process Conditions ◽  
Operating Pressure ◽  
Gas Temperature ◽  
Tracking Model

In this work, an atomizer with a de Laval-type nozzle is designed and studied by commercial computational fluid dynamics (CFD) software, and the secondary breakup process during atomization is simulated by two-way coupling and the discrete particle model (DPM) using the Euler-Lagrange method. The simulation result demonstrates that the gas flow patterns greatly change with the introduction of liquid droplets, which clearly indicates that the mass loading effect is quite significant as a result of the gas-droplet interactions. An hourglass shape of the cloud of disintegrating molten metal particles is observed by using a stochastic tracking model. Finally, this simulation approach is used for the quantitative evaluation of the effects of altering the atomizing process conditions (gas-to-melt ratio, operating pressure P, and operating gas temperature T) and nozzle geometry (protrusion length h, half-taper angle α, and gas slit nozzle diameter D) on the particle size distribution of the powders produced.

scholarly journals Encapsulation of Menthol in Beeswax by a Supercritical Fluid Technique

2010 ◽  
Vol 2010 ◽  
pp. 1-7 ◽  
Author(s):  
Linjing Zhu ◽  
Hongqiao Lan ◽  
Bingjing He ◽  
Wei Hong ◽  
Jun Li
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Flow Rate ◽  
Saturated Solution ◽  
Narrow Particle Size Distribution ◽  
Solution Flow Rate ◽  
Process Conditions ◽  
Solution Flow ◽  
Expansion Temperature

Encapsulation of menthol in beeswax was prepared by a modified particles from gas-saturated solutions (PGSS) process with controlling the gas-saturated solution flow rate. Menthol/beeswax particles with size in the range of 2–50 μm were produced. The effects of the process conditions, namely, the pre-expansion pressure, pre-expansion temperature, gas-saturated solution flow rate, and menthol composition, on the particle size, particle size distribution, and menthol encapsulation rate were investigated. Results indicated that in the range of studied conditions, increase of the pressure, decrease of the gas-saturated solution flow rate, and decrease of the menthol mass fraction can decrease the particle size and narrow particle size distribution of the produced menthol/beeswax microparticles. An N2-blowing method was proposed to measure the menthol release from the menthol/beeswax microparticles. Results showed that the microparticles have obvious protection of menthol from its volatilization loss.

Synthesis of Titania Powder by Titanium Tetrachloride Oxidation in an Aerosol Flow Reactor

1991 ◽  
Vol 249 ◽  
Author(s):  
M. Kamal Akhtar ◽  
Yun Xiong ◽  
Sotiris E. Pratsinis
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Residence Time ◽  
Titanium Tetrachloride ◽  
Flow Reactor ◽  
Geometric Standard Deviation ◽  
Process Conditions ◽  
Average Particle ◽  
Powder Size

ABSTRACTVapor phase synthesis of titania particles by oxidation of titanium tetrachloride (TiCI4) was studied in an aerosol reactor between 1200 K and 1723 K. The effect of process variables (reactor residence time, temperature, reactant concentration) on powder size and phase characteristics was investigated using the differential mobility particle sizer, scanning electron microscopy and X-ray diffraction. The morphology of the particles remained unchanged under the process conditions investigated; titania particles were primarily anatase though the rutile weight fraction increased with increase in reactor temperature. The geometric number average diameter of the particles was between 0.13 µm and 0.35 [m and the geometric standard deviation of the particle size distribution was about 1.4. The average particle size increased with increasing temperature, TiCI4 concentration and residence time. The observed changes in the particle size distribution were compared with those predicted by solving the aerosol dynamic equation by a sectional method and accounting for coagulation and first order chemical reaction.

scholarly journals Curcumin-loaded sterically stabilized nanodispersion based on non-ionic colloidal system induced by ultrasound and solvent diffusion-evaporation

2016 ◽  
Vol 88 (1-2) ◽  
pp. 43-60 ◽  
Author(s):  
Khang Wei Tan ◽  
Siah Ying Tang ◽  
Renjan Thomas ◽  
Neela Vasanthakumari ◽  
Sivakumar Manickam
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Stability Study ◽  
Narrow Particle Size Distribution ◽  
Process Conditions ◽  
Colloidal System ◽  
Ambient Conditions ◽  
Solution Ph

AbstractCurcumin has been found to possess significant pharmaceutical activities. However, owing to its low bioavailability, there is a limitation of employing it towards clinical application. In an attempt to surmount this implication, often the choice is designing novel drug delivery systems. Herein, sterically stabilized nanoscale dispersion loaded with curcumin (nanodispersion) based on non-ionic colloidal system has been proposed. In this study, the process conditions were effectively optimized using response surface methodology (RSM) with Box–Behnken design (BBD). The suggested optimum formulation proved to be an excellent fit to the actual experimental output. STEM images illustrate that the optimal curcumin-loaded nanodispersion has spherical morphology with narrow particle size distribution. Particle size distribution study confirms that the solution pH does not affect the nanodispersion, and physical stability study shows that the colloidal system is stable over 90 days of storage at ambient conditions. More importantly, controlled release profile was achieved over 72 h and the in vitro drug release data fit well to Higuchi model (R2=0.9654).

scholarly journals Improvement of a 1D Population Balance Model for Twin-Screw Wet Granulation by Using Identifiability Analysis

Pharmaceutics ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 692
Author(s):  
Ana Alejandra Barrera Jiménez ◽  
Daan Van Hauwermeiren ◽  
Michiel Peeters ◽  
Thomas De Beer ◽  
Ingmar Nopens
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Population Balance ◽  
Wet Granulation ◽  
Process Conditions ◽  
Model Parameters ◽  
Modeling Tools ◽  
Identifiability Analysis ◽  
Twin Screw

Recently, the pharmaceutical industry has undergone changes in the production of solid oral dosages from traditional inefficient and expensive batch production to continuous manufacturing. The latest advancements include increased use of continuous twin-screw wet granulation and application of advanced modeling tools such as Population Balance Models (PBMs). However, improved understanding of the physical process within the granulator and improvement of current population balance models are necessary for the continuous production process to be successful in practice. In this study, an existing compartmental one-dimensional PBM of a twin-screw granulation process was improved by altering the original aggregation kernel in the wetting zone as a result of an identifiability analysis. In addition, a strategy was successfully applied to reduce the number of model parameters to be calibrated in both the wetting zone and kneading zones. It was found that the new aggregation kernel in the wetting zone is capable of reproducing the particle size distribution that is experimentally observed at different process conditions as well as different types of formulations, varying in hydrophilicity and API concentration. Finally, it was observed that model parameters could be linked not only to the material properties but also to the liquid to solid ratio, paving the way to create a generic PBM to predict the particle size distribution of a new formulation.

Effect of Process Parameters on the Particle Size Distribution of Paclitaxel Nanocrystals

2020 ◽  
Vol 12 (2) ◽  
pp. 137-146
Author(s):  
Gannimitta Arvind ◽  
Srinivas Prathima ◽  
Atla Venkateshwar Reddy
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Response Surface ◽  
Size Distribution ◽  
Process Parameters ◽  
Physicochemical Characteristics ◽  
Precipitation Method ◽  
Influence Of Process Parameters ◽  
Predicted Values ◽  
Two Phases

The main intention of this work was to study the effect of process variables on the particle size distribution of paclitaxel nanocrystals. Paclitaxel nanocrystals were prepared by using anti-solvent precipitation method. Box Behnken design was used to optimize the process parameters including the Ratio (v/v) of two phases (A), Ulatrasonication time in min (B) and Surfactant concentration (%w/v) (C). A response surface methodology comprising 17 runs was carried out to optimize the nanocrystal formulation of paclitaxel. Two dependent variables particle size and polydispersity index (PDI) were identified as responses. Polynomial equations and response surface curves were used to relate the dependent and independent variables. The optimization model predicted a mean particle size of 147.653 nm and PDI of 0.1706 with A, B and C levels of 5, 15 min and 0.03% w/v respectively. The observed values were in close agreement with the predicted values. The optimized batches of nanocrystals were analyzed by FTIR, DSC and XRPD techniques. The optimized batch revealed irregular morphology as assessed by transmission electron microscopy and was crystalline as determined by thermal analysis and XRPD studies. Paclitaxel nanocrystals exhibited a considerable increase in solubility as well as dissolution rate in comparison with the pure drug. The present work thoroughly explored the influence of process parameters on the physicochemical characteristics of the produced drug nanocrystals.

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