scholarly journals Rational crushing of mineral raw materials by well charges as a factor of environmental safety of blasting works in quarries

2021 ◽  
Vol 64 ◽  
pp. 138-153
Author(s):  
V Kolesnik ◽  
A Pavlychenko ◽  
T Kholodenko ◽  
A Kirichenko
Keyword(s):  
Particle Size ◽  
Rock Mass ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Construction Materials ◽  
Environmental Safety ◽  
Shock Adiabats ◽  
Rock Destruction ◽  
Dust Emissions

Purpose. Improving the environmental safety of blasting operations in quarries for the extraction of non-metallic and construction materials based on their rational explosive crushing, aimed at reducing the effect of overgrinding, accompanied by the formation of fine fractions of materials and significant dust emissions. The research methodology provided a theoretical analysis of the destruction processes of a rock massif by well charges of explosives on the basis of calculations of shock adiabats of an explosive wave in rocks at different speeds of detonation of explosives. Experimental verification of the identified patterns was performed by assessing the quality of blasting by the particle size distribution of the rock in the collapse. Research results. The scientific and practical task of ensuring rational explosive crushing of materials in quarries with the use of elongated borehole charges has been solved. Mechanisms for the destruction of rock massifs and the peculiarities of the distribution of destruction zones by dispersed composition have been established, which contributes to the reduction of dust emissions into the atmosphere to an acceptable level of environmental safety of blasting operations in quarries. Comparative estimates of the shock load during the explosion of the explosive charge for the main rocks at different levels of the rate of detonation of charges are given. The dependence of the volume of overgrinding rock in the zone of its adjacency to the charge on the detonation velocity of explosives has been established. An experimental verification of the identified patterns in the current quarry by assessing the quality of blasting by the particle size distribution of rock mass in its collapse after experimental explosions with different parameters is done. Scientific novelty. The multiphase process of rock destruction by explosion was investigated by the calculated determination of the parameters of the shock adiabats of the blast wave in different rocks and at different detonation velocities of explosives. It is shown that during the destruction of a rock mass by the explosion of an elongated borehole charge of explosives, several specific zones of destruction are formed, the characteristics of which differ in particle size distribution. The area of controlled crushing is highlighted, where the intensity of rock destruction can be changed by adjusting the parameters of the explosive load and the area of little or almost unregulated crushing. The possibility of managing the process of dust formation and, accordingly, the level of environmental safety of blasting works in quarries for the extraction of non-metallic and construction materials is substantiated. Practical meaning. The identified patterns and provisions to reduce the effect of mineral overgrinding were used in the development of measures to improve the environmental safety of blasting in the quarry, which, in particular, provided an increase in well spacing in the range up to 3.0-3.4 m and reduce specific energy consumption from 1.27 g/cm3 to 0.97 g/cm3.

The Quality of U100 Sampling

1986 ◽  
Vol 2 (1) ◽  
pp. 419-423
Author(s):  
I. L. Whyte
Keyword(s):  
Particle Size ◽  
Moisture Content ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
General Purpose ◽  
Volume Changes ◽  
Sample Quality ◽  
Class 1 ◽  
Sample Disturbance

AbstractThe origins and development of the U100 (U4) thick-walled open-drive sampler are reviewed. The requirements of CP 2001 and BS 5930 are examined in relation to sample quality, and these are shown to be too favourable. Causes of sample disturbance are considered, particularly those due to volume changes, and shown to depend on moisture content, plasticity and particle size distribution. Quality classes possible with conventional U100 samples are suggested, and Classes 3 or 4 are to be generally expected. Class 1 samples are improbable. It is recommended that a general purpose sampler such as the U100 should have a maximum inside clearance of 1% and not ‘about 1%’ as recommended in BS 5930.

Effect of the particulate morphology of resin on the gelation process of PVC plastisols

2017 ◽  
Vol 37 (8) ◽  
pp. 757-764 ◽  
Author(s):  
Yubi Ji ◽  
Zhao Yang ◽  
Min Shi ◽  
Hong Tan
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Key Factors ◽  
Factors Affecting ◽  
Gelation Process ◽  
Secondary Particles ◽  
Poly Vinyl Chloride ◽  
Opposite Behavior

Abstract The gelation process of poly(vinyl chloride) (PVC) plastisol is very important to ensure the quality of the product and is affected by the type of resins, plasticizers, and other additives. In this study, the gelation process of the as-prepared PVC plastisol was characterized by measuring the evolution of vibrational viscosity with temperature or time using a vibrational viscometer. Furthermore, the effect of some commercial resins with different particulate morphologies on the gelation process was investigated by synchronously combining scanning election microscopy and laser particle size analyses. The results of this study proved that the particle size distribution and the aggregation degree of the secondary particles of a resin are the key factors affecting the gelation process. For the resin with bimodal particle size distribution, the closer the aggregation of the secondary particles, the slower the gel speed; however, an opposite behavior was observed for the resins with unimodal particle size distribution.

scholarly journals INFLUENCE OF PARAMETERS OF EXPLOSIVE DESTRUCTION OF MINING BLOCKS OF COMPLEX GEOLOGICAL STRUCTURE ON THE PREPARATION OF THE MINING MASS FOR PROCESSING

2018 ◽  
pp. 68-74
Author(s):  
К.V. Babii
Keyword(s):  
Particle Size ◽  
Rock Mass ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Iron Ore ◽  
Geological Structure ◽  
Contact Zones ◽  
Complex Geological Structure ◽  
A Charge ◽  
Explosive Destruction

Purpose: to investigate the influence of the parameters of explosive destruction of mining blocks of complex geological structure on the production processes of mining and processing of iron ore. Determine the stability of the escarpment slopes during excavation of rocks in ore mining blocks with barren layers. Results. The analysis of geophysical methods for studying the structure of deposits. It is proposed to use the magnetic susceptibility method for well logging. The structure of mining blocks of a complex geological structure with contact zones "ore - host rocks" was investigated. It has been proven that for the effective use of equipment for the pre-enrichment of ore in a quarry there are conditions: the regulation of the granulometric composition of the rock mass and the reduction of ore splices with overburden rocks. It is proposed to use a charge design of an explosive with inert gaps or a charge section of a cumulative action in the explosive destruction of rocks with contact zones. The influence of parameters of explosive destruction of mining blocks of complex geological structure on the formation of technological complexes of ore beneficiation in quarries is established. The dependence of the factor of stability of slopes of slopes during excavation of rocks, depending on the geological parameters. Scientific novelty. The regularities of changes in the parameters of the ore mass flow (medium piece and oversize) are established depending on the diameter of the drilling-blast wells, which allows you to adjust the particle size distribution. Practical significance. Based on the established patterns and improvement of the design of well charges, their influence on the quality of the blown-up rock mass in the ledges of a complex geological structure has been substantiated, which makes it possible to form the corresponding technological complexes of ore dressing in quarries. The result is a significant increase in the productivity of the technological equipment of the mining enterprise and the profitability of iron ore mining. Key words: quarry, ledge, complex geological structure, downhole charge structures, particle size distribution.

scholarly journals Risiko des Eintrags von Phosphor in den Hallwilersee durch Bodenerosion

2015 ◽  
Vol 70 (3) ◽  
pp. 193-198 ◽  
Author(s):  
S. Müller ◽  
D. Schaub
Keyword(s):  
Particle Size ◽  
Soil Erosion ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Surface Waters ◽  
Aggregate Stability ◽  
Eutrophic Lake ◽  
Soil Samples

Abstract. An important factor in the release of phosphorus by soil erosion, with corresponding consequences on the quality of surface waters, is the formation of aggregates and their stability. Around the eutrophic Lake Hallwil six arable lands were examined in five repetitions regarding aggregate and particle size distribution, P-contents of the different fractions and aggregate stability. Central to this was the use of the setting column for fractionation of soil samples. In the case of Lake Hallwil the risk of phosphorus discharges by soil erosion seems low since the phosphorus is mainly bound in aggregates which are transported over short distances only. Thus other pathways (runoff from grassland, leaching via drains) may be more important.

Анализ параметров медицинского технологического оборудования, учитывающие факторы, влияющие на качество изготовления лекарств

2020 ◽  
pp. 90-95
Author(s):  
T.V. Karlova ◽  
◽  
D.O. Sv ◽  
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Particle Shape ◽  
Particle Surface ◽  
Technological Equipment ◽  
Factors Affecting ◽  
Particle Strength ◽  
The Web

The article is devoted to the analysis of parameters of medical technological equipment that take into account factors affecting the quality of manufacture of drugs. Factors such as particle size, particle size distribution, particle shape, particle surface properties, particle strength, which, based on the «Web» method, are used to analyze the «vibrosieve» technological equipment, are considered.

Modelling and Simulation of Particle Breakage in Jaw Crushers

2011 ◽  
Vol 130-134 ◽  
pp. 1148-1151
Author(s):  
Li Mei Zhao ◽  
Lun Jun Chen ◽  
Da Bin Zhang ◽  
Yi Li
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Performance Model ◽  
Eccentric Shaft ◽  
Parallel Strip ◽  
Object Of Study ◽  
Strip Length ◽  
Jaw Crushers

Jaw crushers are commonly-used machines in aggregate production. The aim of the research is to present a model which is able to predict particle size distribution in jaw crushers and to provide a new method for effectively controlling the quality of crushed product. The object of study was a domestic PEF 400×600 jaw crusher. A performance model was developed based on the standard mass balance formulation and chamber dividing results. Some important parameters that influence the particle output of the crushers were taken into account in the model. The variations of the particle size distribution resulting from changes in the eccentric shaft rotational speed and the parallel strip length were investigated.

Study of Particle Size Distribution of Selected Material of Solid Fertilizer by Using Photo-Optical Image Analysis

2014 ◽  
Vol 1059 ◽  
pp. 19-25
Author(s):  
Miroslav Macák ◽  
Ladislav Nozdrovický
Keyword(s):  
Particle Size ◽  
Image Analysis ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Production Systems ◽  
Physical And Mechanical Properties ◽  
Optical Image ◽  
National Standard ◽  
Sieve Analysis

In many branches of industrial production, there is a need for continual monitoring of the quality of manufactured product. Such requirements arise in the production of fertilizers, as the physical and mechanical properties of fertilizers affect the quality of application provided by fertilizer spreaders. The aim of the presented paper was to compare the suitability and applicability of the photo-optical image analysis with the sieve analysis used for the determination of fertilizer particle size distribution. The photo-optical method was used by [1] to study the fertilizer particle size distribution. These researchers tried to measure the size and velocity of flying particles in relation to the quality of application of centrifugal spreaders. During our comparative experiments, we have compared the photo-optical image analysis and sieve analysis. In experiments, we used the samples of the granulated fertilizer NMgS produced by the Duslo, a.s. company. The sieve analysis was conducted according to the national standard STN EN 1235 in the laboratories of the Department of Machines and Production Systems at the Faculty of Engineering, Slovak University of Agriculture in Nitra.

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