scholarly journals Evaluation of Mechanical Properties and Microscopic Structure of Coal Gangue after Aqueous Solution Treatment

Materials ◽  
2019 ◽  
Vol 12 (19) ◽  
pp. 3207 ◽  
Author(s):  
Yan Zhang ◽  
Xiaoyun Yang ◽  
Susan Tighe
Keyword(s):  
Mechanical Properties ◽  
Aqueous Solution ◽  
Building Materials ◽  
Water Environment ◽  
Solution Treatment ◽  
Coal Gangue ◽  
Engineering Properties ◽  
Coal Waste ◽  
Microscopic Structure ◽  
X Ray

Coal gangue, a solid waste produced in coal production, had caused serious environmental pollution due to accumulation on dumps. Embankment filling can solve the problem while significantly consuming the amount of coal waste for mining. The main purpose of this study is to investigate the mechanical properties and microscopic structure of coal gangue when it is subjected to erosion from water environment with different acidity. Using immersion testing to evaluate its stability in different hydro-chemical environments. Mechanical property parameters of coal gangue treated by solutions were investigated. The action microstructure of coal gangue was revealed through a series of X-ray diffraction (XRD), X-ray fluorescence spectrometry (XRF), scanning electron microscopy (SEM), and energy dispersive spectrometry (EDS). The results show that acidic solution behaved better improvement effect on compressive modulus and fraction of coal gangue samples owing to the generation of quartz and the reduction of aluminum, dissolving of some substances, and transforming of small scattered angular grains through soaking treatment. Alkalinity treatment can be chosen to improve cohesion of coal gangue as a result of polymeric silicon aluminum salt, with high viscosity, was produced by chemical reaction during immersion. Therefore, aqueous solution treatment contributes to engineering properties and presents great potential in both supplement road building materials and recycling of coal gangue.

Heterogeneous Fenton Catalytic Removal of Organic Pollutant in Aqueous Solution by using Coal Gangue as a Catalyst

2019 ◽  
Vol 12 (4) ◽  
pp. 312-325
Author(s):  
Jiwei Zhang ◽  
Jingjing Xu ◽  
Shuaixia Liu ◽  
Baoxiang Gu ◽  
Feng Chen ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Hydrogen Peroxide ◽  
Hydroxyl Radical ◽  
Removal Rate ◽  
Organic Pollutant ◽  
Coal Gangue ◽  
Ion Leakage ◽  
Heterogeneous Fenton ◽  
Solution Ph ◽  
X Ray

Background: Coal gangue was used as a catalyst in heterogeneous Fenton process for the degradation of azo dye and phenol. The influencing factors, such as solution pH gangue concentration and hydrogen peroxide dosage were investigated, and the reaction mechanism between coal gangue and hydrogen peroxide was also discussed. Methods: Experimental results showed that coal gangue has the ability to activate hydrogen peroxide to degrade environmental pollutants in aqueous solution. Under optimal conditions, after 60 minutes of treatment, more than 90.57% of reactive red dye was removed, and the removal efficiency of Chemical Oxygen Demand (COD) up to 72.83%. Results: Both hydroxyl radical and superoxide radical anion participated in the degradation of organic pollutant but hydroxyl radical predominated. Stability tests for coal gangue were also carried out via the continuous degradation experiment and ion leakage analysis. After five times continuous degradation, dye removal rate decreased slightly and the leached Fe was still at very low level (2.24-3.02 mg L-1). The results of Scanning Electron Microscope (SEM), energy dispersive X-Ray Spectrometer (EDS) and X-Ray Powder Diffraction (XRD) indicated that coal gangue catalyst is stable after five times continuous reuse. Conclusion: The progress in this research suggested that coal gangue is a potential nature catalyst for the efficient degradation of organic pollutant in water and wastewater via the Fenton reaction.

Effect of Processing Conditions on Properties of KMnO4-Treated PAN Fibers

2013 ◽  
Vol 821-822 ◽  
pp. 23-27
Author(s):  
Xiang Li ◽  
Chun Yi Liu ◽  
Ai Wen Qin ◽  
Xin Zhen Zhao ◽  
Chun Ju He
Keyword(s):  
Mechanical Properties ◽  
Aqueous Solution ◽  
Chemical Structure ◽  
Suitable Condition ◽  
Wide Angle ◽  
Processing Conditions ◽  
X Ray Diffraction ◽  
X Ray ◽  
Scanning Electron ◽  
Pan Fibers

Plasticized polyacrylonitrile(PAN) fibers have been chemically impregnated with aqueous solution of KMnO4under varying conditions of temperature and time. The effect of modification conditions on the chemical structure and the mechanical properties of precursor fibers are characterized by wide-angle X-ray diffraction, Fourier transform infrared spectroscopy and scanning electron microscope. The experimental results show that KMnO4can be used not only as catalyst for cyclization reaction, but also as plasticizer. The chemical modification between KMnO4and PAN can not occur below70°C, the most suitable condition for modification is performed at 80°C for 5 min.

scholarly journals Dispersibility of Kaolinite-Rich Coal Gangue in Rubber Matrix and the Mechanical Properties and Thermal Stability of the Composites

Minerals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1388
Author(s):  
Kenan Zhang ◽  
Hao Zhang ◽  
Linsong Liu ◽  
Yongjie Yang ◽  
Lihui Liu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Coal Gangue ◽  
Rubber Matrix ◽  
Styrene Butadiene Rubber ◽  
Butadiene Rubber ◽  
Scanning Calorimetry ◽  
Laser Scattering ◽  
X Ray ◽  
Thermal Stability Of

The aim of this work was to investigate the dispersibility of kaolinite-rich coal gangue in rubber matrix, the mechanical properties and thermal stability of coal gangue/styrene butadiene rubber (SBR) composites, and to compare these properties to those of the same coal gangue but had undergone thermal activation and modification. Several experimental techniques, such as X-ray diffraction (XRD), X-ray fluorescence (XRF), scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), thermogravimetric-differential scanning calorimetry (TG-DSC), laser-scattering particle analyzer were adopted to characterize the coal gangue particles and then the obtained composites. The results demonstrated the raw coal gangue (RCG) was mainly composed of kaolinite. Calcination led to amorphization of thermal activated coal gangue (ACG), increased hydrophilicity and void volume, and decreased pH. The grain size of ACG became coarser than RCG, but ACG turned loose confirmed by higher degree of refinement after grinding. Modification enhanced the hydrophobicity of the coal gangue and improved its dispersibility than fillers without modification. Calcined samples had better dispersibility than uncalcined fillers. Additionally, the coal gangue treated by calcinating, grinding and modifying (MGA) had the best dispersion in rubber matrix. Either calcination or modification could improve the mechanical properties and thermal stability of coal gangue filled rubber, while the performance of MGA reinforced SBR (MGA-SBR) was the best. The enhanced performance of the MGA-SBR was owed to better dispersion of particles as well as stronger interactions between particles and rubber macromolecules.

scholarly journals Influence of different sources of coal gangue used as aluminosilicate powder on the mechanical properties and microstructure of alkali-activated cement

2019 ◽  
Vol 69 (336) ◽  
pp. 199 ◽  
Author(s):  
B. J. Frasson ◽  
R. C.A. Pinto ◽  
J. C. Rocha
Keyword(s):  
Mechanical Properties ◽  
Coal Mining ◽  
Building Materials ◽  
Mechanical Performance ◽  
Pulse Velocity ◽  
Coal Gangue ◽  
Microstructural Development ◽  
Mining Wastes ◽  
Alkali Activated ◽  
Alkali Activated Cement

Coal mining wastes are associated with serious environmental problems; they have potential as building materials, including alkali-activated cement. In this study, the effect of different coal mining wastes on the mechanical properties and microstructural development of alkali-activated materials (AAMs) was evaluated through XRD, SEM and FTIR spectroscopy. Different alkali-activated compounds were produced; the alkaline solution was composed of NaOH+Na2SiO3. The results obtained using the calcined coal sludge showed excellent mechanical performance, with compressive strength higher than 60 MPa. However, addition of metakaolin and ordinary Portland cement was necessary to increase the mechanical performance of calcined coal gangue materials. The formation of N-A-S-H gel and the incorporation of iron ions into the cementitious matrix were evidenced. Ultrasonic pulse velocity indicated the early polymerization during the reaction processes. The study verified that the different characteristics of the wastes influence the performance of alkali-activated materials.

scholarly journals Zn-Al Layered Double Hydroxide Thin Film Fabricated by the Sputtering Method and Aqueous Solution Treatment

Coatings ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 669
Author(s):  
Jaehwan Shin ◽  
Kyunghwan Kim ◽  
Jeongsoo Hong
Keyword(s):  
Aqueous Solution ◽  
Solution Treatment ◽  
X Ray Diffraction ◽  
Zno Film ◽  
Experiment Data ◽  
X Ray ◽  
Facing Target Sputtering ◽  
Double Hydroxide ◽  
Double Hydroxides ◽  
Synthesis Experiment

Zn-Al layered double hydroxides (LDHs) were synthesized herein via a simple process. First, Al-doped ZnO film was deposited onto a glass substrate using the facing target sputtering system. Successful synthesis of the Zn–Al LDH was achieved via a treatment process using an aqueous solution which contains NO3− anions. X-ray diffraction analysis confirmed that it was consistent with the previous Zn–Al LDH synthesis experiment data, and the calculated d-value was 9.1 Å. Scanning electron microscopy observations revealed that the as-synthesized sample had a plate-like structure.

scholarly journals Evaluation for the Leaching of Cr from Coal Gangue Using Expansive Soils

Processes ◽  
2019 ◽  
Vol 7 (8) ◽  
pp. 478 ◽  
Author(s):  
Yan Zhang ◽  
Hassan Baaj ◽  
Rong Zhao
Keyword(s):  
Heavy Metal ◽  
Compressive Strength ◽  
Unconfined Compressive Strength ◽  
Building Materials ◽  
Negative Impact ◽  
Expansive Soil ◽  
Coal Gangue ◽  
Engineering Properties ◽  
Leaching Behavior ◽  
The Impact

Coal gangue can cause significant heavy metal pollution in mining areas, which would have a negative impact on the environment and human health. The objective of this research is to investigate the relationship between expansive soil amount and the leaching behavior of Chromium from coal gangue and the engineering properties of coal gangue used as building materials. The leaching behavior of Chromium from coal gangue was observed using atomic absorption spectrometry. A column leaching experiment was conducted to examine the impact of leaching time and heavy metal concentration. Furthermore, the unconfined compressive strength test was employed to evaluate the engineering properties of coal gangue with expansive soil. The results of the study demonstrate that pH of leachate solutions, leaching time, and expansive soil amounts in mixtures have important influence on Chromium concentration. The leachate solutions, which behave like alkaline, provide a positive environment for adsorbing Cr. Adding expansive soil can reduce leached concentrations of Chromium from coal gangue when compared to leachate of original coal gangue. It was found that 30% expansive soil was an improved solution because it delayed the cumulative concentration to reach the limitation line. Moreover, the unconfined compressive strength of coal gangue was boosted through adding expansive soil.

Influence of Yttrium and Heat Treatment on Microstructure and Mechanical Properties of AM60 Alloy

2011 ◽  
Vol 194-196 ◽  
pp. 1319-1325
Author(s):  
Zheng Tian ◽  
Zhan Yi Cao ◽  
Jian Meng
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Solid Solution ◽  
Yield Strength ◽  
Solution Treatment ◽  
Aging Treatment ◽  
Hardness Measurement ◽  
X Ray ◽  
Solid Solution Treatment ◽  
Yttrium Addition

The effect of yttrium addition and heat treatment on the mechanical properties and microstructure of AM60 magnesium alloy have been investigated using X-ray phase analysis, microstructure investigation, tensile test, hardness measurement and fracture surfaces analysis. The results showed that the mechanical properties of the alloys were obviously improved with the addition of yttrium no more than 1.0%. The reinforcement of the alloys resulted from the appearance of Al2Y phase. After solid-solution treatment (T4), the Mg17Al12 phase almost dissolved in Mg matrix, but the rare earth compounds Al2Y phase was rather stable. The ultimate tensile strength σb was improved, but the yield strength σ0.2 and elongation δ were only slightly changed. After solid-solution + aging treatment (T6), the Mg17Al12 phase precipitated again and their morphology was changed. The yield strength σ0.2 was improved.

Microstructural and Mechanical Properties of Ti3Al-Based Intermetallics Produced by Powder Metallurgy

2005 ◽  
Vol 494 ◽  
pp. 211-216 ◽  
Author(s):  
B. Dimčić ◽  
M. Vilotijević ◽  
D. Božić ◽  
D. Rajnović ◽  
M.T. Jovanović
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Powder Metallurgy ◽  
Room Temperature ◽  
Solution Treatment ◽  
Microstructural Characterization ◽  
Compression Tests ◽  
X Ray Diffraction ◽  
X Ray ◽  
Scanning Electron

The structural and compression mechanical properties of Ti3Al-based intermetallics produced by powder metallurgy techniques have been studied. The as-milled powders were compacted by hot pressing to non-porous homogenous compacts. Prior to compression tests, all compacts were homogenized by a solution treatment at 1050°C (a+β region) for 1h, followed by water quenching. The compression tests were performed from room temperature to 500°C in vacuum at a strain rate of 1 3 10 4 . 2 − − × s . Detailed microstructural characterization was evaluated by scanning electron microscopy (SEM), followed by energy dispersive spectroscopy (EDS) and X-ray diffraction analysis.

scholarly journals The Effect of Solution Treatment on Mechanical Properties and Micro Structure of Zr-10Ti-Sn Alloy for Screw Dental Implant Application

2021 ◽  
Vol 2 (2) ◽  
pp. 91
Author(s):  
Deva Ayu Utami ◽  
R. Henny Mulyani ◽  
Djoko Hadi Prajitno
Keyword(s):  
Mechanical Properties ◽  
Corrosion Resistance ◽  
Dental Implant ◽  
Solution Treatment ◽  
Hardness Test ◽  
Alpha Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Good Corrosion Resistance ◽  
Low Modulus

<p>The research was to investigate the effect of solution treatment on the mechanical properties and microstructure of Zr-10Ti-Sn alloy for dental implant biomaterials. The addition of titanium as a material has good corrosion resistance and stannum as a material has a low modulus young and can increase hardness of the alloy in accordance with the material criteria as a dental implant, which must have good corrosion resistance and good mechanical properties. Zr -10Ti-xSn alloy (x = 0, 2, and 4% wt) were subjected to solution treatment with temperature variations of 900<sup>o</sup>C, 1000<sup>o</sup>C and 1100<sup>o</sup>C with water quenching. The results  is increase in stannum content can also increase the hardness because stannum can inhibit the enlargement of grain boundaries and the microstructure is more homogeneous and tends to be smaller with an uniaxial shape. Stannum as alpha stabilizer will form a hard alpha phase. Micro Vickers hardness test with the highest hardness value of 601,438 HV alloy Zr-10Ti-2Sn with 900<sup>o</sup>C solution treatment, phases formed were α-Zr and β-Zr and intermetallic Zr<sub>4</sub>Sn and SnTi<sub>3</sub> Zr-10Ti-4Sn alloys which were identified using X-Ray Diffraction (XRD).</p>

Effects of Swelling Treatments on Fine Structure and Mechanical Properties of Cellophane Film

1988 ◽  
Vol 58 (4) ◽  
pp. 233-238
Author(s):  
N. V. Bhat ◽  
D. N. Makwana
Keyword(s):  
Mechanical Properties ◽  
Aqueous Solution ◽  
Tensile Strength ◽  
Fine Structure ◽  
Sonic Velocity ◽  
X Ray Diffraction ◽  
X Ray ◽  
Structural Modifications ◽  
Cellophane Film ◽  
Tearing Strength

Commercial cellophane film was studied, primarily with a view to determining structural modifications as a result of swelling treatments. Cellophane films were subjected to swelling in ethylenediamine, pyridine, and an aqueous solution of sodium hydroxide. Structural properties such as crystallinity and crystallite size were determined by x-ray diffraction. Changes in orientation were followed by determining birefringence and sonic velocity. Mechanical properties such as tensile strength, elongation, and tearing strength were also studied. An analysis of the data revealed that the swelling treatment increases the crystallinity, which improves the mechanical properties.

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