scholarly journals Lead-Zinc Mine Tailings Valorization Through Fly Ash-Based Geopolymer for Building Material: Synthesis, Microstructure, and Mechanical Properties

2021 ◽  
Author(s):  
ALSENY BAH ◽  
Andrea ORTIZ Ramos ◽  
Feng Daolun ◽  
jie Jin ◽  
Alhassane Bah ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Mine Tailings ◽  
Unconfined Compressive Strength ◽  
Building Materials ◽  
Fourier Transforms ◽  
Coal Fly Ash ◽  
Environmentally Friendly ◽  
Cement Industry ◽  
Moderate Amount

Abstract Using geopolymerization to value mining wastes in order to meet construction demand is a sustainable and environmentally friendly strategy. Fly ash geopolymer materials have been developed to address environmental issues such as climate change caused by the emissions of CO2 from coal fly ash plants, mining, and cement industry into the atmosphere. The main objective of this study is to study the feasibility of using mine tailings to produce environmentally friendly building materials (so-called geopolymer products) with excellent mechanical strength through fly-based geopolymer technology. Fly ash (F.A.) and mine tailings (M.T.) were utilized as raw materials and gypsum (G.Y.) as additives. Sodium hydroxide (NaOH) at (5-10M) and sodium silicate (water glass) constituted the alkaline solution and were added separately to the mixture. The mechanical property and microstructure of the geopolymers were assessed by performing the Unconfined Compressive Strength (UCS), Scanning Electron Microscopy (SEM), X-ray diffractions (XRD), and Fourier transforms infrared (FTIR). A 24 MPa was achieved at 10M NaOH with 100% F.A. Besides, low UCS values were obtained with only M.T. as a binder. The SEM imaging analysis confirmed similar results showing that the geopolymer specimens cured with 100% of F.A. at 10M NaOH with a moderate amount of gypsum are denser than those prepared without gypsum at 5M. The findings revealed that F.A., MT, and gypsum, together with the alkali reagents, influenced the geopolymerisation process. These factors responded effectively to the microstructural performance(increasing density), resulting in increased unconfined compressive strength.

An Investigation of Usability of Brown Coal Fly Ash for Building Materials

2013 ◽  
Vol 438-439 ◽  
pp. 30-35 ◽  
Author(s):  
Nirdosha Gamage ◽  
Sujeeva Setunge ◽  
Kasuni Liyanage
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Brown Coal ◽  
Water Contamination ◽  
Building Materials ◽  
Coal Fly Ash ◽  
Sustainable Building ◽  
Laboratory Investigations ◽  
Cold Pressed ◽  
Initial Results

The Victoria State of Australia has the second largest reserves of brown coal on earth, representing approximately 20% of the worlds reserves, and at current use, could supply Victoria with its energy for over 500 years. Its combustion, annually, yields up to 1.3 million tonnes of fly ash, which is largely use for land-fills. Disposal of fly ash in open dumps cause massive environmental problems such as ground water contamination that may create various health problems. This study focuses on the usability of brown coal fly ash to develop a sustainable building material. A series of laboratory investigations was conducted using brown coal fly ash combined with cement and aggregate to prepare cold pressed samples aiming to test their properties. Initial results indicate that compressive strength satisfies minimum standard compressive strength required for bricks or mortar.

scholarly journals Synthesis of Geopolymer from Coal Fly Ash and its Comparative Study with Fly Ash Based Ordinary Nepalese Cement

2020 ◽  
Vol 13 (13) ◽  
pp. 24-28 ◽  
Author(s):  
Deepa Humbahadur Gurung ◽  
Vinay Kumar Jha
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Comparative Study ◽  
Cement Mortar ◽  
Coal Fly Ash ◽  
Cement Industry ◽  
Mass Ratio ◽  
Cement Mortars ◽  
The Comparative Study ◽  
Alkali Activated

The world cement industry is responsible for 5-8 % of the total CO2 emission. Thus, the cement industry has a crucial role in global warming. The search for an alternative green inorganic binder with improved durability led to the discovery of alkali-activated binder termed “geopolymer”. In this study, geopolymer was synthesized from coal fly ash (CFA) with the parameters such as particle size ≤ 53 μm, NaOH concentration 8 M and the mass ratio of CFA/Na2SiO3 was 0.75. For the comparative study with fly ash based cement, the cement mortars were prepared by varying the cements and mass ratio. The highest compressive strength (14.16 MPa) of the cement mortar was however obtained with 1:3 cement sand ratio after 7 days of curing, the ratio of 1:4 was considered for comparison. The cement and geopolymer mixture mortars were also prepared with varying (cement + sand) and (CFA+ NaOH+ Na2SiO3) mass ratio. The maximum compressive strength of 3.84 MPa was obtained for 1:2 mass ratio with 7 days of curing. The maximum compressive strengths of CFA based geopolymer, CFA added cement and cement and geopolymer mixture were 17.06, 21.3 and 11.42 MPa with 90 days of curing respectively.

scholarly journals Characterization and Comparison Research on Composite of Alluvial Clayey Soil Modified with Fine Aggregates of Construction Waste and Fly Ash

2021 ◽  
Vol 28 (1) ◽  
pp. 83-95
Author(s):  
Qu Jili ◽  
Wang Junfeng ◽  
Batugin Andrian ◽  
Zhu Hao
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Unconfined Compressive Strength ◽  
Clayey Soil ◽  
Dry Density ◽  
Maximum Dry Density ◽  
Construction Waste ◽  
Comparison Research ◽  
Fine Aggregates ◽  
Optimum Water Content

Abstract Fine aggregates of construction waste and fly ash were selected as additives to modify the characteristics of Shanghai clayey soil as a composite. The laboratory tests on consistency index, maximum dry density, and unconfined compressive strength were carried out mainly for the purpose of comparing the modifying effect on the composite from fine aggregates of construction waste with that from fly ash. It is mainly concluded from test results that the liquid and plastic limit of the composites increase with the content of two additives. But their maximum dry density all decreases with the additive content. However, fine aggregates of construction waste can increase the optimum water content of the composites, while fly ash on the contrary. Finally, although the two additive all can increase the unconfined compressive strength of composites, fly ash has better effect. The current conclusions are also compared with previous studies, which indicates that the current research results are not completely the same as those from other researchers.

scholarly journals Production of ceramics from coal fly ash

2012 ◽  
Vol 18 (2) ◽  
pp. 245-254 ◽  
Author(s):  
Biljana Angjusheva ◽  
Emilija Fidancevska ◽  
Vojo Jovanov
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Solid State ◽  
Liquid Phase ◽  
Bending Strength ◽  
Coal Fly Ash ◽  
Liquid Phase Sintering ◽  
Heating Rates ◽  
Republic Of Macedonia ◽  
The Subject

Dense ceramics are produced from fly ash from REK Bitola, Republic of Macedonia. Four types of fly ash from electro filters and one from the collected zone with particles < 0.063 mm were the subject of this research. Consolidation was achieved by pressing (P= 133 MPa) and sintering (950, 1000, 1050 and 11000C and heating rates of 3 and 100/min). Densification was realized by liquid phase sintering and solid state reaction where diopside [Ca(Mg,Al)(Si,Al)2O6] was formed. Ceramics with optimal properties (porosity 2.96?0.5%, bending strength - 47.01?2 MPa, compressive strength - 170 ?5 MPa) was produced at 1100?C using the heating rate of 10?C/min.

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