Strength And Environmental Properties Of Cemented Paste Backfill That Contains Sodium Silicate
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Strength And Environmental Properties Of Cemented Paste Backfill That Contains Sodium Silicate
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Author : Hoda Mohammad Pour
language : en
Publisher:
Release Date : 2020
Strength And Environmental Properties Of Cemented Paste Backfill That Contains Sodium Silicate written by Hoda Mohammad Pour and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2020 with categories.
Mining is an important industry that plays a significant role in the development of human civilization and economies. However, the underground mining process produces a large volume of mine wastes (e.g., tailings) as well as creates large voids that require filling, typically with an engineering backfill material. Filling the voids with mine waste materials provides an environmental-friendly way of disposing mining waste. It is also an effective way of increasing ore recovery and improving the safety of miners. One of the best techniques of mine backfill is called cemented paste backfill (CPB), which is typically a mixture of tailings, binder and water. The most common binder used in the preparation of CPB is Portland cement (PC). PC is not only a costly binder, but its production is highly energy-intensive and also generates a large amount of CO2. The cement consumption can represent up to 75% of the cost of CPB. These above-mentioned factors have compelled mining companies to seek for cement alternatives that enhance the engineering properties of the CPB, decrease the cement content and reduce the carbon footprint of the mining industry. Sodium silicate is the most recent chemical additive that is proposed to reduce the binder content in CPB. Sodium silicate is an alkaline solution that is used to activate a pozzolanic material, such as cement, slag and Fly ash. However, the effect of sodium silicate on the strength and key environmental properties (permeability or saturated hydraulic conductivity, reactivity) of CPB is not well understood. The objective of this thesis is to investigate the possibility of using sodium silicate as an activator in cemented paste backfill and obtain an improvement in the aforementioned engineering properties of CPB. In order to determine the effect of the sodium silicate on backfill properties, some CPB testing methods were developed to fulfill the objectives of this research. Thus, the evolution of hydraulic, mechanical and microstructural properties of CPB samples containing sodium silicate (SS-CPB) have been tested or monitored at different curing ages (1, 3, 7, 28 and 90 days) and different CPB mixtures as well. The results of these studies show that activating CPB with sodium silicate develop CPB strength faster than CPB samples without sodium silicate. In addition, hydraulic conductivity and reactivity results show a positive change in samples containing sodium silicate compared to free sodium silicate CPB samples. Indeed, this activation leads to decreasing permeability and reactivity due to the formation of cement hydration products and acceleration of the binder hydration process. Moreover, binder type and content in the presence of sodium silicate as an alkali activator in the CPB play a significant role in lowering hydraulic conductivity and reactivity of CPB.
Cemented Paste Backfill
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Author : Yong Wang
language : en
Publisher: Elsevier
Release Date : 2024-05-19
Cemented Paste Backfill written by Yong Wang and has been published by Elsevier this book supported file pdf, txt, epub, kindle and other format this book has been release on 2024-05-19 with Science categories.
In view of the demand for the research on the transport resistance characteristics and mechanical properties of CPB under the influence of temperature effect, the book comprehensively describes the studies on rheological and mechanical properties of CPB materials used in underground metal mines. This book covers a wide range of topics, including a new definition of CPB, past participation and flow-induced corrosion of pipeline under the constant temperature condition, multiphysics processes in CPB and the associated consolidation process, the variation of rheological parameters and transport resistance, prediction model for rheological properties, mechanical behavior and properties of CPB and fiber-reinforced CPB, and control technology to reduce the adverse effect of temperature. Therefore, an academic framework for the transport resistance characteristics and mechanical properties under the temperature effect was established in this book. - Investigates rheological properties and multiphysics processes in CPB materials around the world - Looks into systematic studies on pipe transport and mechanical properties of CPB under temperature effects - Focuses mainly on the effect of temperature on paste transport and mechanical properties under the temperature effect, which provides a theoretical basis for safe and efficient filling operation and associated future research in this field - Offer in-depth insights into the evolution of the rheological and mechanical properties of CPB under the effect of temperatures
Paste Tailings Management
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Author : Erol Yilmaz
language : en
Publisher: Springer
Release Date : 2017-03-03
Paste Tailings Management written by Erol Yilmaz and has been published by Springer this book supported file pdf, txt, epub, kindle and other format this book has been release on 2017-03-03 with Technology & Engineering categories.
This book provides an overview of paste tailings disposal at mine sites. It deals comprehensively with the characterization of sulphide-rich tailings, geotechnical and microstructural behaviour, surface tailings disposal applications, underground paste backfilling, and case studies. The authors place emphasis on the characterization, monitoring, disposal and treatment, as well as environmental considerations of problematic sulphidic tailings. The framework is supported by worldwide case studies.
Non Bf Slag Based Green Cementitious Materials
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Author : Lijie Guo
language : en
Publisher: Frontiers Media SA
Release Date : 2022-08-12
Non Bf Slag Based Green Cementitious Materials written by Lijie Guo and has been published by Frontiers Media SA this book supported file pdf, txt, epub, kindle and other format this book has been release on 2022-08-12 with Technology & Engineering categories.
Minefill 2020 2021
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Author : Ferri Hassani
language : en
Publisher: CRC Press
Release Date : 2021-06-02
Minefill 2020 2021 written by Ferri Hassani and has been published by CRC Press this book supported file pdf, txt, epub, kindle and other format this book has been release on 2021-06-02 with Technology & Engineering categories.
The series of International Symposiums on Mining with Backfill explores both the theoretical and practical aspects of the application of mine fill, with many case studies from both underground and open-pit mines. Minefill attendees and the Proceedings book audience include mining practitioners, engineering students, operating and regulatory professionals, consultants, academics, researchers, and interested individuals and groups. The papers presented at Minefill symposiums regularly offer the novelties and most modern technical solutions in technology, equipment, and research. In that way, the papers submitted for the Minefill Symposia represent the highest quality and level in the conference domain. For the 2020-2021 edition organizers hope that the papers presented in this publication will also be received with interest by readers around the world, providing inspiration and valuable examples for industry and R&D research.
Temperature Dependency Of The Rheological Properties And Strength Of Cemented Paste Backfill That Contains Sodium Silicate
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Author : Ghada Abdulbaqi Ali
language : en
Publisher:
Release Date : 2021
Temperature Dependency Of The Rheological Properties And Strength Of Cemented Paste Backfill That Contains Sodium Silicate written by Ghada Abdulbaqi Ali and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2021 with categories.
Over the past decades, cemented paste backfill (CPB) has become a common, environmentally friendly method of managing mine wastes (such as tailings). This technology allows up to 60% of the total amount of tailings to be reused and filled in the mine stopes after converting them into cemented material. Beside reducing the environmental risks associated with the traditional disposal of these materials, turning them into cemented material and placing them in the underground mine stopes can also provide secondary support for these stopes in addition to minimizing the risk of ground subsidence in the mine area. CPB is an engineered mixture of tailings, water, and hydraulic binder (such as cement, blast furnace slag, and fly ash) that is mixed in the paste plant and delivered into the mine stopes through a gravity or pumping based transportation system. During the transportation of CPB through the delivery system pipelines, the flowability of CPB depends on the rheology of the transported CPB, which is affected by different factors, such as the transportation time, temperature variation, binder type, and chemical composition of these mixtures. In addition, the performance of CPB, after placing the CPB mixture into the mine stopes, is mainly dependent on the role of the hydraulic binder, as it increases the mechanical strength of the mixture through the process of cement hydration. The mechanical strength is also influenced by different factors, such as time progress, temperature variation, and presence of chemical additives. It has previously been found that fresh CPB transported and/or placed in the mine stopes can be susceptible to temperature variation of different sources, such as the climatic effects, heat generated from the surrounding rocks, and heat generated during the process of cement hydration. Unsuitable flowability of CPB through the delivery system might lead to significant financial losses due to clogging of pipelines with unexpected hardening of CPB during transportation, which will cause delay in work and possible damages to the pipelines. Also, failure of CPB structure in the mine stopes due to inappropriate mechanical strength may cause casualties to the mine workers as well as significant environmental and economic damages. Many researchers studied the rheological properties and/or strength development of CPB under the individual effect of any of the aforementioned factors. Additionally, many researchers have evaluated the coupled effect of some of these factors on the rheology and mechanical strength of CPB material. Hitherto, there are currently no studies that addressed the combined effect of all these conditions on the rheological properties and strength development of CPB. At the first stage of this M.A.Sc. study, a series of experimental tests was conducted on fresh CPB in order to determine the combined effect of time, temperature, binder content, and chemical additives on the rheological properties of CPB. These experiments include rheological properties test (yield stress and viscosity), microstructural analysis (thermal analysis and XRD), chemical analysis (pH and Zeta potential), and monitoring tests (electrical conductivity), which were conducted on 125 CPB samples that were mixed and prepared at different temperatures (2oC, 20oC, 35oC) and cured for different curing time (0 hrs., 0.25 hrs., 1 hr., 2hrs, and 4 hrs.). These samples were prepared with different blends of hydraulic binders (PCI, PCI/Slag, and PCI/FA) and contained different dosages of sodium silicate (0%, 0.1%, 0.3%, and 0.5%). The results obtained show that rheology of CPB increases with the progress of curing time. It also increases with the increase in the initial (mixing and curing) temperature and content of sodium silicate. It was also found that the partial usage of slag and FA reduces the rheological properties. However, CPBs containing PCI/FA as binder have lower rheological properties, and thus better flowability, than those that contain PCI/Slag as binder. At the second stage of this M.A.Sc. study, in order to understand the combined effect of time, temperature and sodium silicate content on the strength development of slag-CPB, unconfined compression (UCS) test, microstructural analysis (thermal analysis and MIP), and monitoring tests (electrical conductivity, suction, and volumetric water content) were conducted on 72 CPB samples that were prepared with PCI-Slag as a binder, cured for different times (1 day, 3 days, 7 days, and 28 days) under different curing temperatures of (2oC, 20oC, 35oC), and contained different dosages of sodium silicate (0%, 0.3% and 0.5%). The results obtained at this stage showed that the strength development of slag-CPB increases with the progress of curing time and temperature. It also increases with the increase in the sodium silicate content. Also, the combined effect of high temperature, high dosage of sodium silicate and longer curing time showed significant enhancement in the mechanical strength of slag-CPB. The findings of this M.A.Sc. research will contribute to cost effective, efficient, and safer design of CPB structures in the mine areas. It will also help in minimizing financial loss associated with unsuitable flowability of CPB transported in the CPB delivery system besides reducing the risks of human loss, and the environmental and economic damages associated with the failure of CPB structures.
Advances In Design And Implementation Of Cementitious Backfills Adicb
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Author : Erol Yilmaz
language : en
Publisher: Frontiers Media SA
Release Date : 2022-10-05
Advances In Design And Implementation Of Cementitious Backfills Adicb written by Erol Yilmaz and has been published by Frontiers Media SA this book supported file pdf, txt, epub, kindle and other format this book has been release on 2022-10-05 with Technology & Engineering categories.
Recent Trends In Phosphate Mining And Beneficiation And Related Waste Management
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Author : Mostafa Benzaazoua
language : en
Publisher: MDPI
Release Date : 2020-02-11
Recent Trends In Phosphate Mining And Beneficiation And Related Waste Management written by Mostafa Benzaazoua and has been published by MDPI this book supported file pdf, txt, epub, kindle and other format this book has been release on 2020-02-11 with Science categories.
The extraction of apatite minerals is becoming more and more crucial with the depletion of high-grade ores. At the same time, many streams of waste are continuously being produced by the phosphate industry, including calcareous and siliceous waste rocks, clayey sludge and phosphogypsum. These waste products are produced in huge volumes reaching a ratio of between 5 to 10 tons of waste per each ton of concentrated phosphate. The management of these waste products is becoming a real issue in terms of growing public awareness and environmental and financial aspects. In addition, phosphate ores are known to contain other critical raw materials (CRM) such as rare earth elements and uranium. The recovery of these vital elements from phosphate waste may help to develop the needs of the green energy of the future and contribute to the achievement of the sustainable development goals. In this Special Issue, insights related to the following aspects were studied: phosphate extraction and beneficiation, novel phosphate ores, the fine characterization of phosphate ores and waste, phosphoric acid production, critical raw material (CRM) recovery from phosphate ores and waste, reprocessing of phosphate wastes and finally the valorization and reuse of phosphate waste and phosphogypsum.
Fluid Flow In Fractured Porous Media
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Author : Richeng Liu
language : en
Publisher: MDPI
Release Date : 2019-09-30
Fluid Flow In Fractured Porous Media written by Richeng Liu and has been published by MDPI this book supported file pdf, txt, epub, kindle and other format this book has been release on 2019-09-30 with Technology & Engineering categories.
The fluid flow in fracture porous media plays a significant role in the assessment of deep underground reservoirs, such as through CO2 sequestration, enhanced oil recovery, and geothermal energy development. Many methods have been employed—from laboratory experimentation to theoretical analysis and numerical simulations—and allowed for many useful conclusions. This Special Issue aims to report on the current advances related to this topic. This collection of 58 papers represents a wide variety of topics, including on granite permeability investigation, grouting, coal mining, roadway, and concrete, to name but a few. We sincerely hope that the papers published in this Special Issue will be an invaluable resource for our readers.
Dissertation Abstracts International
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Author :
language : en
Publisher:
Release Date : 2008
Dissertation Abstracts International written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2008 with Dissertations, Academic categories.