Determination of the wetting angle using gas bubble method

2021 ◽  
Vol 87 (4) ◽  
pp. 38-42
Author(s):  
Yu. F. Patrakov ◽  
S. A. Semenova
Keyword(s):  
Contact Angle ◽  
Particle Size ◽  
Surface Characterization ◽  
Wetting Angle ◽  
Powdered Sample ◽  
Pressing Pressure ◽  
Gas Bubble ◽  
Working Surface ◽  
Coal Particles ◽  
Contact Angle Of Wetting

Most of the technological processes of coal mining and primary processing (transportation, crushing, and enrichment) depend on the physical and chemical properties of the external surface of coal particles. When determining the wetting angle — the wettability characteristics of the coal surface — the method of preparing the working surface of the sample and the choice of the measurement procedure (a drop of liquid on a solid surface or fixing a gas bubble on the surface of coal placed in water) are of great importance. We present the results of determining the contact angle of wetting using an air bubble. The working surface was prepared by briquetting a powdered sample. Scanning electron microscopy and laser diffraction analysis of the particle size distribution were used for surface characterization and fractional analysis of carbon particles. It is shown that the contact angle of wetting depends on the particle size, mineral composition of coal, and pressing pressure. At the same time, when determining the wetting angle, the optimal particle size and pressing pressure of the briquette are <100 μm and ~500 MPa, respectively. The obtained results can be used to improve technologies for mining, conversion and dressing of coals.

scholarly journals Effect of ash existence in the coal particles on the dewatering performance of fine coal

2020 ◽  
Author(s):  
Suhong Zhang ◽  
Ni Gao ◽  
Ke Zhao
Keyword(s):  
Contact Angle ◽  
Particle Size ◽  
Moisture Content ◽  
Coal Sample ◽  
Ash Content ◽  
Primary Role ◽  
Fine Coal ◽  
Angle Measurements ◽  
Coal Particles ◽  
Contact Angle Measurements

Abstract The dewatering experiments of fine coal with different ash contents in the particle size range of 0.125 mm − 0 mm were investigated in this study. Structures of coal samples were characterized by X-ray diffractometer (XRD) and surface functional groups were detected by Fourier transform infrared (FTIR). Wettability and wetting heats of coal samples were determined by contact angle measurements and micro-calorimeter system, respectively. In this study, the dewatering results indicate that the ash content of fine coal had less effect on the coal dewatering than the coalification degree in the dewatering process. However, for the given coal sample the moisture content was significantly affected by the ash content while the coal particle size was less than 0.125 mm. The decrease of moisture content in coal sample after the ash was removed indicating that the hydrophobic property of coal surface was enhanced based on contact angle measurements and wetting heats. In addition, kaolinite played a primary role of minerals in coal for the coal dewatering.

scholarly journals Characterization of Steel Slag Filler and Its Effect on Aging Resistance of Asphalt Mastic with Various Aging Methods

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 869
Author(s):  
Minghua Wei ◽  
Shaopeng Wu ◽  
Haiqin Xu ◽  
Hechuan Li ◽  
Chao Yang
Keyword(s):  
Particle Size ◽  
Surface Characterization ◽  
Steel Slag ◽  
Self Healing ◽  
Limestone Filler ◽  
Asphalt Mastic ◽  
Pore Characterization ◽  
Asphalt Mastics ◽  
Healing Property

Steel slag is the by-product of the steelmaking industry, the negative influences of which prompt more investigation into the recycling methods of steel slag. The purpose of this study is to characterize steel slag filler and study its feasibility of replacing limestone filler in asphalt concrete by evaluating the resistance of asphalt mastic under various aging methods. Firstly, steel slag filler, limestone filler, virgin asphalt, steel slag filler asphalt mastic and limestone filler asphalt mastic were prepared. Subsequently, particle size distribution, surface characterization and pore characterization of the fillers were evaluated. Finally, rheological property, self-healing property and chemical functional groups of the asphalt mastics with various aging methods were tested via dynamic shear rheometer and Fourier transform infrared spectrometer. The results show that there are similar particle size distributions, however, different surface characterization and pore characterization in the fillers. The analysis to asphalt mastics demonstrates how the addition of steel slag filler contributes to the resistance of asphalt mastic under the environment of acid and alkaline but is harmful under UV radiation especially. In addition, the pore structure in steel slag filler should be a potential explanation for the changing resistance of the asphalt mastics. In conclusion, steel slag filler is suggested to replace limestone filler under the environment of acid and alkaline, and environmental factor should be taken into consideration when steel slag filler is applied to replace natural fillers in asphalt mastic.

Penetration Dynamics of Solid Particles into Liquids High-Speed Experimental Results and Modelling

2005 ◽  
Vol 473-474 ◽  
pp. 429-434 ◽  
Author(s):  
Olga Verezub ◽  
György Kaptay ◽  
Tomiharu Matsushita ◽  
Kusuhiro Mukai
Keyword(s):  
Contact Angle ◽  
Particle Size ◽  
Aqueous Solutions ◽  
Particle Velocity ◽  
Weber Number ◽  
High Speed ◽  
Solid Particles ◽  
Bulk Liquid ◽  
Distilled Water ◽  
Critical Weber Number

Penetration of model solid particles (polymer, teflon, nylon, alumina) into transparent model liquids (distilled water and aqueous solutions of KI) were recorded by a high speed (500 frames per second) camera, while the particles were dropped from different heights vertically on the still surface of the liquids. In all cases a cavity has been found to form behind the solid particle, penetrating into the liquid. For each particle/liquid combination the critical dropping height has been measured, above which the particle was able to penetrate into the bulk liquid. Based on this, the critical impact particle velocity, and also the critical Weber number of penetration have been established. The critical Weber number of penetration was modelled as a function of the contact angle, particle size and the ratio of the density of solid particles to the density of the liquid.

scholarly journals A two-jet arc plasma: matrix effects and ways to their suppression

2019 ◽  
Vol 85 (1II)) ◽  
pp. 139-144
Author(s):  
N. P. Zaksas ◽  
A. F. Veryaskin
Keyword(s):  
Thermal Stability ◽  
Particle Size ◽  
Biological Samples ◽  
Matrix Effects ◽  
Certified Reference Materials ◽  
Organic Matrix ◽  
Graphite Powder ◽  
Powdered Sample ◽  
Experimental Conditions ◽  
Emission Analysis

A two-jet plasma is used for direct atomic emission analysis of powdered samples. It is characterized by relatively weak matrix effects, which allows using unified calibration samples on the basis of graphite powder for analysis of the samples with inorganic, organic, and organomineral matrix. In the present paper the effects limiting the usage of the unified approach due to different thermal stability and evaporation efficiency of the samples are discussed. The understated concentrations of a set of elements (Al, Ba, Ca, La, Mg, Mn, Sr, Ti, and Y) were obtained in analysis of certified reference materials of geological samples. It was shown that determination of rare earth elements should be carried out in the region behind the jet confluence providing their complete evaporation. For other elements, registration of the spectra in this region improves the results to some extent but they do not achieve the certified values. To speed up evaporation of these elements, the experimental conditions were chosen for plasma chemical reactions which provide conversion of the matrix elements into more volatile compounds. Addition of ammonium hydrofluoride to powdered sample considerably increased the line intensities of Al and Ca strongly associated with the silicon matrix. Incomplete evaporation was observed in analysis of biological samples with particle size more than 100 μm. A decrease in consumption of carrier argon is quite enough for effective decomposition of the organic matrix in plasma; the value of gas consumption depends on thermal stability and particle size of the sample. Preliminary sample carbonization is another way to improve evaporation of biological samples.

scholarly journals IMPROVEMENT OF THE METHOD OF MEASURING THE CONTACT ANGLE OF WETTING WITH THE USE OF THE COMPASS-3D PROGRAM

2018 ◽  
Vol 25 (1) ◽  
pp. 77
Author(s):  
G. A. Teptereva ◽  
S. Yu. Shavshukova ◽  
V. G. Konesev ◽  
I. I. Sultanov ◽  
R. R. Rakhimov ◽  
...  
Keyword(s):  
Contact Angle ◽  
Contact Angle Of Wetting

scholarly journals Improving the technology of repair painting with powder-coated paints in agro-industrial complex

2021 ◽  
Vol 285 ◽  
pp. 07012
Author(s):  
Andrey Bodrov ◽  
Anton Panichkin ◽  
Denis Lomakin ◽  
Andrew Simushkin
Keyword(s):  
Contact Angle ◽  
Roughness Parameter ◽  
Corrosion Damage ◽  
Industrial Complex ◽  
Powder Coatings ◽  
Chemical Methods ◽  
Painted Surface ◽  
Stain Resistance ◽  
Separation Force ◽  
Contact Angle Of Wetting

The article presents the results of studies to determine the dependence of the degree of adhesion and the separation force of the powder coatings layer on the roughness parameter of the substrate, as well as the contact angle of wetting for various methods of preparing the painted surface by chemical methods. In addition, practical tests for stain resistance were carried out, which showed the absence of corrosion damage, as well as a slight change in color, gloss of coatings, chalking and dirt retention on the studied coating samples.

A matrix analysis of processes involving particle assemblies

1956 ◽  
Vol 249 (960) ◽  
pp. 99-123 ◽  
Keyword(s):  
Particle Size ◽  
Matrix Analysis ◽  
Mathematical Form ◽  
Size Distributions ◽  
Ball Mills ◽  
Particle Assembly ◽  
Coal Particles ◽  
Breakage Function ◽  
Grinding Machine ◽  
Particle Assemblies

The processes analyzed in this paper are the size reduction and size classification of particle assemblies. Particle size distributions are described by vectors, and alterations to size distributions during breakage processes are described by matrices multiplying the vectors. The matrix approximation gives an adequate representation of the processes studied, and the manipulation of the matrices is easy and flexible. The breakage of a particle assembly is thought of as two processes. In the first, the machine breaking the particles is said to select for breakage a proportion of the particles, and the remaining particles are unbroken. To discover a function or matrix which describes the process of selection is to understand how the machine operates. In the second process, the particles selected are broken in a regular way; the proportions of particles of each size formed by the breakage are described by a breakage function or a breakage matrix. The analysis of breakage is in this way given convenient mathematical form. These matrices depend on the characteristics of the machine and on the nature of the particle assembly. After breaking the particles, crushing and grinding machines frequently pass the product assemblies to a classifier from which the larger particles are returned, mixed with fresh material, to the grinding zone. The analysis is extended to the description of such circuits. The experimental work reported concerns the breaking of coal particles in a new grinding machine, ball mills, shatter tests and a beater mill. The selection functions derived throw light on the operation of these machines. Coal breakage has been studied since it is an important field of application, and because coal is typical in breakage of homogeneous rocks. For each of the machines examined and for each particle size, a single breakage function has sufficed to describe the product of breakage: [1 —exp ( —z)]/[ 1 —exp ( — 1)] is the proportion of the product smaller than a fraction z of the original particle size.

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