scholarly journals Metodología geometalúrgica para mejorar el proceso de extracción de oro en pequeña escala de la mina Gualconda en Nariño – Colombia

2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Gabriel Kamilo Pantoja-Barrios ◽  
Eliana Katherine Molina-Ramírez ◽  
Silvia Natalia Fuentes-Torres ◽  
Fabian Andrés Ramírez ◽  
Jaime Mojica ◽  
...  
Keyword(s):  
Particle Size ◽  
Low Cost ◽  
Size Reduction ◽  
Gold Recovery ◽  
Small Scale ◽  
Operational Parameters ◽  
Particle Size Reduction ◽  
Mineralogical Characterization ◽  
Analytical Technique ◽  
Gold Bearing

In the gold beneficiation processes, the degree of particle size reduction is strongly influenced by the size and shape of the mineral species associated with the economically important metals. The capacity, energy consumption, and costs of the gold-bearing ore processing depend mainly on the operational parameters of the equipment of comminution and gravimetric concentration; therefore, it is essential to characterize the liberation degree of the minerals of interest as function of particle size. The small-scale mining beneficiation plants usually do not consider the liberation of sulfide particles as a requirement to define the grinding size reduction ratio, this is determined empirically, evaluating in which size a higherpercentage of gold recovery is obtained. The methodology proposed in this paper constitutes a low cost analytical technique, using the free software IMAGE-J, to determine the appropriate liberation size for sulfide particles and associated gold particles,as well as the size distribution of gold ore particles. Additionally, the Molycop-Tools software was used to simulate the best grinding strategy based on the liberation results obtained.Through the methodology of automatic image analysis to determine the liberation degree of sulfides, the mineralogical characterization, and the recommendation of a metallurgical processing strategy for the gold-bearing ore based on steady-state simulations, it was possible to establish the appropriate parameters of ball mill grinding and gravimetric concentration of the Gualconda mine in the Department of Nariño, in order to improve the gold recovery and increase the plant capacity.

Methods for particle size reduction of liposomal amphotericin B

2018 ◽  
Vol 60 (1) ◽  
pp. 42-45
Author(s):  
Tuan Quang Nguyen ◽  
Van Lam Nguyen ◽  
Thai Son Nguyen ◽  
Thi Minh Hue Pham ◽  
◽  
...  
Keyword(s):  
Particle Size ◽  
Amphotericin B ◽  
Liposomal Amphotericin ◽  
Size Reduction ◽  
Liposomal Amphotericin B ◽  
Particle Size Reduction

scholarly journals Laser Superficial Fusion of Gold Nanoparticles with PEEK Polymer for Cardiovascular Application

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 971
Author(s):  
Oktawian Bialas ◽  
Mateusz Lis ◽  
Anna Woźniak ◽  
Marcin Adamiak
Keyword(s):  
Particle Size ◽  
Laser Beam ◽  
Gold Particle ◽  
Laser Power ◽  
Biomedical Application ◽  
Parameters Optimization ◽  
Size Reduction ◽  
Particle Size Reduction ◽  
Nano Gold ◽  
Gold Particle Size

This paper analyses the possibility of obtaining surface-infused nano gold particles with the polyether ether ketone (PEEK) using picosecond laser treatment. To fuse particles into polymer, the raw surface of PEEK was sputtered with 99.99% Au and micromachined by an A-355 laser device for gold particle size reduction. Biomimetic pattern and parameters optimization were key properties of the design for biomedical application. The structures were investigated by employing surface topography in the presence of micron and sub-micron features. The energy of the laser beam stating the presence of polymer bond thermalisation with remelting due to high temperature was also taken into the account. The process was suited to avoid intensive surface modification that could compromise the mechanical properties of fragile cardiovascular devices. The initial material analysis was conducted by power–depth dependence using confocal microscopy. The evaluation of gold particle size reduction was performed with scanning electron microscopy (SEM), secondary electron (SE) and quadrant backscatter electron detector (QBSD) and energy dispersive spectroscopy (EDS) analysis. The visibility of the constituted coating was checked by a commercial grade X-ray that is commonly used in hospitals. Attempts to reduce deposited gold coating to the size of Au nanoparticles (Au NPs) and to fuse them into the groove using a laser beam have been successfully completed. The relationship between the laser power and the characteristics of the particles remaining in the laser irradiation area has been established. A significant increase in quantity was achieved using laser power with a minimum power of 15 mW. The obtained results allowed for the continuation of the pilot study for augmented research and material properties analysis.

scholarly journals Characterization of Astaxanthin Nanoemulsions Produced by Intense Fluid Shear through a Self-Throttling Nanometer Range Annular Orifice Valve-Based High-Pressure Homogenizer

Molecules ◽  
2021 ◽  
Vol 26 (10) ◽  
pp. 2856
Author(s):  
Gary B. Smejkal ◽  
Edmund Y. Ting ◽  
Karthik Nambi Arul Nambi ◽  
Richard T. Schumacher ◽  
Alexander V. Lazarev
Keyword(s):  
Particle Size ◽  
Size Reduction ◽  
Hydrodynamic Diameter ◽  
Fluid Shear ◽  
Particle Size Reduction ◽  
Annular Gap ◽  
Oil In Water ◽  
High Pressure Homogenizer ◽  
Pass Through

Stable, oil-in-water nanoemulsions containing astaxanthin (AsX) were produced by intense fluid shear forces resulting from pumping a coarse reagent emulsion through a self-throttling annular gap valve at 300 MPa. Compared to crude emulsions prepared by conventional homogenization, a size reduction of over two orders of magnitude was observed for AsX-encapsulated oil droplets following just one pass through the annular valve. In krill oil formulations, the mean hydrodynamic diameter of lipid particles was reduced to 60 nm after only two passes through the valve and reached a minimal size of 24 nm after eight passes. Repeated processing of samples through the valve progressively decreased lipid particle size, with an inflection in the rate of particle size reduction generally observed after 2–4 passes. Krill- and argan oil-based nanoemulsions were produced using an Ultra Shear Technology™ (UST™) approach and characterized in terms of their small particle size, low polydispersity, and stability.

scholarly journals Sonocrystallization—Case Studies of Salicylamide Particle Size Reduction and Isoniazid Derivative Synthesis and Crystallization

Crystals ◽  
2018 ◽  
Vol 8 (6) ◽  
pp. 249 ◽  
Author(s):  
Zhen-Yu Yang ◽  
Shih-Kuo Yen ◽  
Wei-Syun Hu ◽  
Yu-Zhe Huang ◽  
Tsung-Mao Yang ◽  
...  
Keyword(s):  
Particle Size ◽  
Case Studies ◽  
Size Reduction ◽  
Particle Size Reduction

Substrate particle size reduction by Bacillus coagulans in solid-state fermentation

1996 ◽  
Vol 18 (2) ◽  
pp. 121-125 ◽  
Author(s):  
M.P. Nandakumar ◽  
M.S. Thakur ◽  
K.S.M.S. Raghavarao ◽  
N.P. Ghildyal
Keyword(s):  
Particle Size ◽  
Solid State ◽  
Solid State Fermentation ◽  
Bacillus Coagulans ◽  
Size Reduction ◽  
Particle Size Reduction ◽  
Substrate Particle

Liquid antisolvent recrystallization and solid dispersion of flufenamic acid with polyvinylpyrrolidone K-30

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Rahul Kumar ◽  
Sanjay Kumar ◽  
Pranava Chaudhari ◽  
Amit K. Thakur
Keyword(s):  
Particle Size ◽  
Dissolution Rate ◽  
Solid Dispersion ◽  
Fine Particles ◽  
Xrd Analysis ◽  
Solution Concentration ◽  
Injection Rate ◽  
Size Reduction ◽  
Flufenamic Acid ◽  
Particle Size Reduction

Abstract Flufenamic acid (FFA) is a Biopharmaceutical Classification System- II (BCS-II) class drug with poor bioavailability and a lower dissolution rate. Particle size reduction is one of the conventional approaches to increase the dissolution rate and subsequently the bioavailability. The use of the liquid antisolvent method for particle size reduction of FFA was studied in this work. Ethanol and water were used as solvent and antisolvent, respectively. Experimental parameters such as solution concentration (10–40 mg/ml), flow rate (120–480 ml/h), temperature (298–328 K) and stirring speed (200–800 rpm) were investigated. Furthermore, the solid dispersion of FFA was prepared with polyvinylpyrrolidone K-30 (PVP K-30) with different weight ratios (1:1, 1:2, 1:3 and 1:4) and samples were characterized using SEM, FTIR and XRD techniques. The experimental investigation revealed that higher values of concentration, injection rate, stirring speed, along with lower temperature favored the formation of fine particles. SEM analysis revealed that the morphology of raw FFA changed from rock-like to rectangular-like after liquid antisolvent recrystallization. FTIR analysis validated the presence of hydrogen bonding between FFA and PVP in solid dispersion. XRD analysis showed no significant change in the crystallinity of the processed FFA.

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