scholarly journals Methods for intensification of borehole uranium mining at the fields with low filtration characteristics of ores

2021 ◽  
Vol 15 (3) ◽  
pp. 95-101
Author(s):  
Zhiger Kenzhetaev ◽  
Marzhan Nurbekova ◽  
Kuanysh Togizov ◽  
Moldir Abdraimova ◽  
Bakytzhan Toktaruly
Keyword(s):  
Sulphuric Acid ◽  
Hydrogen Fluoride ◽  
Mineralogical Composition ◽  
Uranium Mining ◽  
Industrial Safety ◽  
Phase Method ◽  
Uranium Deposits ◽  
Advantages And Disadvantages ◽  
Before And After ◽  
Ammonium Hydrogen

Purpose. Improving the efficiency of borehole uranium mining and the selection of special decolmating solutions to improve the filtration characteristics of the seam due to effective destruction, as well as by preventing the sedimentation in the productive horizon, depending on the mineralogical composition and structure of sediment-forming materials. Methods. The advantages and disadvantages of the main methods used for improving the filtration characteristics of the productive horizon, when mining the uranium deposits by the borehole method, have been studied. Samples of sedimentation from the productive horizon are taken at the uranium deposit of the Shu-Syrasu depression. The quantitative and qualitative parameters, as well as the peculiarities of the mineral compositions have been determined by the X-ray phase method. A methodology has been developed and laboratory experiments have been conducted on the treatment of sedimentation samples by the drop method using various compositions of selected decolmating solutions. The microscopic method is used to determine the structure and peculiarities of sedimentation before and after treatment with various decolmating solutions. Findings. The effectiveness of the main methods used to improve the filtration characteristics of seams in the uranium deposits, mined by the borehole method, has been determined. The structure and composition of sedimentation, which causes a decrease in the filtration characteristics of the productive horizon, have been determined. To destroy and prevent the sedimentation in the productive horizon, an effective composition of a special decolmating solution using ammonium hydrogen fluoride with the addition of sulphuric acid and surfactants has been selected. An effective method for increasing the filtration characteristics of the productive horizon with the use of special decolmating solutions has been developed and scientifically substantiated. Originality. The use of special decolmating solutions based on ammonium hydrogen fluoride with the addition of sulphuric acid and surfactants according to the developed methodology allows to effectively destroy and prevent sedimentation in the productive horizon of borehole uranium ore mining. Practical implications. The use of the developed decolmating solution and a special methodology for the intensification of borehole uranium mining can reduce the operating costs of its production. This increases the ecological and industrial safety of the work to intensify the leaching of uranium ores.

Sedimentary Clays as Geopolymer Precursor

2018 ◽  
Vol 39 ◽  
pp. 97-111
Author(s):  
F. Mostefa ◽  
Nasr Eddine Bouhamou ◽  
H.A. Mesbah ◽  
Salima Aggoun ◽  
D. Mekhatria
Keyword(s):  
Sodium Hydroxide ◽  
Mineralogical Composition ◽  
Cementitious Materials ◽  
Raw Material ◽  
X Ray Diffraction ◽  
Calcination Time ◽  
Calorimetric Analysis ◽  
X Ray ◽  
Before And After ◽  
Mechanical Performances

This work aims to study the feasibility of making a geopolymer cement based on dredged sediments, from the Fergoug dam (Algeria) and to evaluate their construction potential particularly interesting in the field of special cementitious materials. These sediments due to their mineralogical composition as aluminosilicates; are materials that can be used after heat treatment. Sedimentary clays were characterized before and after calcination by X-ray diffraction, ATG / ATD, spectroscopy (FTIR) and XRF analysis. The calcination was carried out on the raw material sieved at 80 μm for a temperature of 750 ° C, for 3.4 and 5 hours. The reactivity of the calcined products was measured using isothermal calorimetric analysis (DSC) on pastes prepared by mixing an alkaline solution of sodium hydroxide (NaOH) 8 M in an amount allowing to have a Na / Al ratio close to 1 (1: 1). Also, cubic mortar samples were prepared with a ratio L / S: 0.8, sealed and cured for 24 hours at 60 ° C and then at room temperature until the day they were submited to mechanical testing. to check the extent of geopolymerization. The results obtained allowed to optimize the calcination time of 5 hours for a better reactivity of these sediments, and a concentration of 8M of sodium hydroxide and more suitable to have the best mechanical performances.

Comparison of a Non Electrostatic Surface Complexation Model and Surface Phase Theories for Prediction of Future Sorption Properties.

2004 ◽  
Vol 824 ◽  
Author(s):  
Allan T. Emrén ◽  
Anna-Maria Jacobsson
Keyword(s):  
Aqueous Solution ◽  
Chemical Potential ◽  
Surface Complexation ◽  
Sorption Properties ◽  
Phase Method ◽  
Detailed Knowledge ◽  
Surface Phase ◽  
Surface Complexation Model ◽  
Advantages And Disadvantages ◽  
The One

AbstractIn performance assessments, sorption of radionuclides dissolved in groundwater is mostly handled by the use of fixed Kd values. It has been well known that this approach is unsatisfying. Only during the last few years, however, tools have become available that make it possible to predict the actual Kd value in an aqueous solution that differs from the one in which the sorption properties were measured.One such approach is surface complexation (SC) that gives a detailed knowledge of the sorption properties. In SC, one tries to find what kinds of sorbed species are available on the surface and the thermodynamics for their formation from species in the bulk aqueous solution. Recently, a different approach, surface phase method (SP), has been developed. In SP, a thin layer including the surface is treated as a separate phase. In the bulk aqueous solution, the surface phase is treated as a virtual component, and from the chemical potential of this component, the sorption properties can be found.In the paper, we compare advantages and disadvantages of the two kinds of models. We also investigate the differences in predicted sorption properties of a number of radionuclides (Co, Np, Th and U). Furthermore, we discuss under which circumstances, one approach or the other is preferable.

scholarly journals Structural changes in clays subjected to heat treatment: an analysis by structural refinement using the Rietveld method

2021 ◽  
Vol 67 (6 Nov-Dec) ◽  
Author(s):  
Mauro Quiroga Agurto ◽  
Elvira Leticia Zeballos Velásquez ◽  
Felipe Americo Reyes Navarro
Keyword(s):  
Heat Treatment ◽  
Structural Changes ◽  
Rietveld Method ◽  
Mineralogical Composition ◽  
Structural Factors ◽  
Expansive Clay ◽  
Structural Refinement ◽  
Weight Percentage ◽  
Before And After ◽  
Cerro De Pasco

Structural factors in clays influence their physical properties. Therefore, it is particularly important to understand the effects of heat treatment on the structure of the material during the ceramic process. In this work, we have analyzed clays from quarries in the Cerro de Pasco region, Peru, to evaluate their characteristics and the structural changes produced by heating, particularly in the interlaminar region. The samples were thermally treated between 150 oC and 800 oC with intervals of 50 oC. To evaluate the structural changes produced by temperature, X-ray diffraction were carried out before and after each heat treatment. The qualitative analysis of the measurements allowed to identify the mineralogical composition of the samples, finding phases of calcium montmorillonite, kaolinite, illite and quartz. The quantitative analysis by the Rietveld method found structural changes, particularly in the Ca-montmorillonite expansive clay. It was also possible to determine the decrease in the weight percentage of the kaolinite until the collapse of its structure between 450 °C and 500 °C. The illite presented greater thermal stability, with slight variations in its weight percentage during heat treatment, without compromising its structure. Although the quartz phase did not show relevant structure changes, it slightly increased its weight percentage with increasing temperature.

scholarly journals Legal and Economic Reglamentation Aspects of Individual Enterprise Functioning

Ekonomika ◽  
2008 ◽  
Vol 81 ◽  
Author(s):  
Dalia Perkumienė ◽  
Vida Čiulevičienė
Keyword(s):  
Legal Entity ◽  
Advantages And Disadvantages ◽  
Individual Enterprise ◽  
Before And After ◽  
The Individual

The operation of individual enterprises established in Lithuania was regulated by various separate laws which caused much inconvenience. Therefore, the Lithuanian law on individual enterprises entered into force on 1 January 2004. The article aims to present the outstanding peculiarities of an individual enterprise as a legal entity which could be considered as advantages and disadvantages. The article considers the individual enterprise before and after the entry into force of the Lithuanian law on individual enterprises.

scholarly journals IMPROVEMENTS IN TEACHERS' KNOWLEDGE AND UNDERSTANDING OF BASIC ASTRONOMY CONCEPTS THROUGH DIDACTIC GAMES

2020 ◽  
Vol 19 (6) ◽  
pp. 1020-1033
Author(s):  
Katarina Susman ◽  
Jerneja Pavlin
Keyword(s):  
Primary School ◽  
School Teachers ◽  
Knowledge Test ◽  
Primary School Teachers ◽  
Moon Phases ◽  
University Teachers ◽  
Advantages And Disadvantages ◽  
Poor Understanding ◽  
Before And After ◽  
Astronomy Concepts

Literature review shows that many primary school teachers have poor understanding of basic astronomy contents. Therefore, the aim of the study was to introduce specific astronomical content to in-service primary school teachers through two didactic games, to evaluate the didactic games and the teachers’ knowledge and understanding before and after the implementation of the didactic games. The research included 24 in-service primary school teachers. The data were collected through the knowledge test (pre-post design) and questionnaires for each didactic game. The results showed that the teachers evaluated the didactic games as suitable for use in the classroom as they emphasized that they are educational, explicit and interesting. The implementation was identified as effective because the median for fractional gains was 0.54 and showed the medium gain in teachers’ knowledge and understanding of selected astronomy contents. It was recognized that in-service primary school teachers do not feel competent for introducing complex astronomical contents to their students. However, the presented approach could encourage in-service primary school teachers to deepen their knowledge and to teach astronomy contents with a method that is closer to their students. University teachers could point out the advantages and disadvantages of didactic games in astronomy content and discuss them with pre-service primary school teachers. Keywords: astronomy education, didactic games, in-service primary school teachers, Moon phases

Fluoride und Fluorosäuren, VI. Verbindungsbildung und Kristallstrukturen im System Ammoniak—Fluorwasserstoff [1, 2] / Fluorides and Fluoro Acids, VI. Compound Formation and Crystal Structures in the System Ammonia-Hydrogen Fluoride

1984 ◽  
Vol 39 (3) ◽  
pp. 290-297 ◽  
Author(s):  
Dietrich Mootz ◽  
Wolfgang Poll
Keyword(s):  
Hydrogen Bonding ◽  
Binary System ◽  
Crystal Structures ◽  
Hydrogen Fluoride ◽  
Melting Diagram ◽  
Melting Points ◽  
Compound Formation ◽  
Ammonium Hydrogen ◽  
Quasi Binary System

The melting diagram of the quasi-binary system NH3-HF between the limits NH4HF2 and HF was redetermined. The compounds NH3 · 4HF, NH3 · 5HF and NH3 · 8HF with melting points of 26, -14 (dec.) and -95 °C (dec.), respectively, were established as the stable phases. Their crystal structures were determined as those of ammonium hydrogen fluorides NH4[F(HF)4], NH4[F(HF)4] and NH4[HF2(HF)3] · 3HF with extended N-H···F and F-H···F hydrogen bonding.

scholarly journals Comparing the Effects of Four Instructional Treatments on EFL Students’ Achievement in Writing Classified Ads

2016 ◽  
Vol 9 (3) ◽  
pp. 139
Author(s):  
Farzaneh Khodabandeh
Keyword(s):  
Proficiency Test ◽  
New Techniques ◽  
Advantages And Disadvantages ◽  
Self Study ◽  
Before And After ◽  
Post Test ◽  
Efl Students ◽  
Instructional Treatments ◽  
Junior Students ◽  
And Task

<p>The current study set out to compare the effect of traditional and non-traditional instructional treatments; i.e. explicit, implicit, task-based and no-instruction approaches on students’ abilities to learn how to write classified ads. 72 junior students who have all taken a course in Reading Journalistic Texts at the Payame-Noor University streamed by performing a TOEFL proficiency test. The selected participants were randomly divided into the following four groups; an explicit group which received direct instruction; an implicit group which were instructed indirectly, and the self-study group with no-instruction treatment in comparison to the task-based group which were asked to prepare a classified ad. A pre-test and a post-test were administered before and after the treatment. The moves in classified ads pre- and post- tests were analyzed through descriptive and inferential statistics. The quantitative analysis of the post-tests revealed that the explicit and task-based groups outperformed the implicit and self-study instruction groups. The findings of this research offer English teachers the chance to reconsider their practices and performances through the advantages and disadvantages of the traditional and new techniques which were employed in the current research and combine them to help learners improve their reading and writing skills.</p>

scholarly journals Increasing of filtration characteristics of ore bodies in borehole uranium mining

2020 ◽  
Vol 168 ◽  
pp. 00014
Author(s):  
Bayan Rakishev ◽  
Zhiger Kenzhetayev ◽  
Asel Shampikova ◽  
Bakytzhan Toktaruly
Keyword(s):  
Experimental Work ◽  
Uranium Mining ◽  
Optimal Parameters ◽  
Chemical Reagents ◽  
Chemical Type ◽  
Ore Bodies ◽  
Geological Conditions ◽  
Before And After ◽  
Degree Of Extraction ◽  
Borehole Mining

There is a description of technology by borehole uranium mining in Kazakhstan. The factors which affect for reduction of filtration characteristics in productive reservoirs are studied in detail and described an effective method for increasing borehole uranium production. The processes that occur during borehole mining of uranium with the use of sulfuric acid as solvent, as well as the conditions and reasons for reducing the productivity of geotechnical wells during their operation are considered. The results of experimental work on the intensification of borehole uranium mining in complex mining and geological conditions are analyzed and discussed, comparative graphs of the content of uranium in the productive solution, the flow rate of wells, the degree of extraction and the volume of production before and after the experiments are constructed. The results of experimental work on the efficiency of borehole uranium production, the content of uranium in PS and the productivity of wells, with predominance of the chemical type of sedimentation, are positively evaluated. The optimal parameters for the intensification of borehole uranium production in complex mining and geological conditions are recommended, and method for using complex of multi-purpose chemical reagents in combination with traditional methods of well regeneration is developed.

scholarly journals Study on the Properties of Transparent Bamboo Prepared by Epoxy Resin Impregnation

Polymers ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 863 ◽  
Author(s):  
Yan Wu ◽  
Yajing Wang ◽  
Feng Yang ◽  
Jing Wang ◽  
Xuehua Wang
Keyword(s):  
Heat Treatment ◽  
Tensile Strength ◽  
Visible Light ◽  
Epoxy Resin ◽  
Raw Materials ◽  
Light Transmittance ◽  
Advantages And Disadvantages ◽  
Heat Treated ◽  
Before And After ◽  
Different Parts

In this paper, Moso bamboo (Phyllostachys heterocycle) before and after heat treatment were used as raw materials to prepare transparent bamboo (TB). In an acidic environment, the lignin contained in the bamboo material was removed to obtain a bamboo template, and an epoxy resin similar to the cellulose refractive index was used for vacuum impregnation into the bamboo template to obtain a transparent bamboo material. The purpose of this study was to compare the physical and chemical properties of TB and original bamboo and the differences between TBs before and after heat treatment, taken from different parts of bamboo, in order to explore the performance advantages and disadvantages of TB as a new material. The Fourier transform infrared spectroscopy analysis (FTIR), scanning electron microscope testing (SEM), three elements analysis, light transmittance testing, and mechanical strength testing were used to study the molecular composition, microstructure, chemical composition, light transmittance, and tensile strength of the TB samples. The results showed that the lignin content of the delignified bamboo templates was greatly reduced. In addition, the SEM images showed that a large amount of epoxy resin (type E51 and type B210 curing agent) was covered on the cross-section surface and pores of the TB samples. The FTIR showed that the epoxy molecular groups appeared on the TB, and the delignified bamboo template and the resin had a good synergy effect. According to the light transmittance testing, the original bamboo samples hardly contained light transmittance under visible light. The transmittance of transparent inner bamboo (TIB) and transparent heat-treated inner bamboo (THIB) could reach about 11%, and the transmittance of transparent outer bamboo (TOB) and transparent heat-treated outer bamboo (THOB) was about 2%. The light transmittance had been significantly improved when compared with the original bamboo samples. The transmittances of the TB samples before and after heat treatment in different parts of bamboo were different. In the visible light irradiation range, the light transmittances of TB samples were as follows: TIB > THIB and THOB > TOB. Meanwhile, the tensile strength of TB was reduced, especially for TOB and THOB. In addition, TB has a wide range of raw materials, and the preparation process is environmentally friendly. It can be used for decorative materials in homes, buildings, etc., and has a great application potential.

The Strategic Value of Big Data Analytics in Health Care Policy-Making

2018 ◽  
Vol 14 (3) ◽  
pp. 20-33 ◽  
Author(s):  
Hamed M. Zolbanin ◽  
Dursun Delen ◽  
Sushil K Sharma
Keyword(s):  
Health Care ◽  
Big Data ◽  
Data Analytics ◽  
Health Care Policy ◽  
Big Data Analytics ◽  
Advantages And Disadvantages ◽  
Strategic Value ◽  
Before And After ◽  
The Government ◽  
New Policies

This article describes how the metrics that are used to gauge acceptable versus inadequate care have spurred debates among health care administrators and scholars. Specifically, they argue that the use of readmissions as a quality-of-care metric may reduce patients' safety. Consequently, the new well-intended policies may prove ineffective, or even worse, yield disappointing results. While the discussions over the advantages and disadvantages of the new policies are based more on conjectures rather than on evidence, analytics provides a vehicle to measure the effectiveness of such overarching strategies. In this effort, the authors analyze large volumes of hospital encounters data before and after the implementation of the Patient Protection and Affordable Care Act (PPACA) to show how overlooking some aspects of a problem may lead to unexpected outcomes. The authors conclude that the feedback provided by big data analytics can be used by the government and organization policymakers to obtain a better understanding of loopholes and to propose more effective policies in prospective endeavors.

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