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Char extracted from coal ash as a replacement for natural graphite – “Charphite”

  • Authors: Badenhorst, Charlotte
  • Date: 2019
  • Subjects: Char , Coal ash , Graphite
  • Language: English
  • Type: Doctoral (Thesis)
  • Identifier: http://hdl.handle.net/10210/416537 , uj:35239
  • Description: Abstract: This thesis forms part of the third ERA-MIN collaboration between Portugal, Poland, Romania, Argentina, and South Africa under the project Charphite. The overall aim of the Charphite project was to determine if char found in coal ash can be used as a substitute replacement for natural graphite in green energy applications, including direct use of char in the electrocatalytic oxygen reduction reaction and the hydrogen oxidation reaction. Ash is a waste product resulting from the combustion of coal. The landfilling or ponding of ash can lead to serious environmental and health concerns, and therefore the utilisation of ash / certain components in the ash is desired. Literature shows that South African coal ash samples (>50 mill ton ash per annum) contain 0.5 to 8 % carbon in ash (chars) and also a significant amount of unburned carbon is associated with carbonaceous shale containing <10 % carbon and >90 % mineral matter. Char in coal ash has a high degree of structural order and can possibly be used as a substitute for natural graphite. The European Union, the United States, and the United Kingdom have all listed natural graphite as one of their raw critical commodities; hence the project has significant merits. Research on producing synthetic graphite from char in coal ash is scarce, with only a limited amount of papers being published as yet. .. , Ph.D. (Geology)
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Electrochemical co-detection of arsenic, lead and mercury on exfoliated graphite nanocomposite electrodes

The role of graphite addition on spark plasma sintered titanium nitride

  • Authors: Akinribide, O. J. , Obadele, B. A. , Ayeleru, O. O. , Akinwamide, S. O. , Nomoto, K. , Eizadjou, M. , Ringer, S. P. , Olubambi, P. A.
  • Date: 2020
  • Subjects: TiN , Graphite , Spark plasma sintering
  • Language: English
  • Type: Article
  • Identifier: http://hdl.handle.net/10210/451622 , uj:39803 , Citation: Akinribide, O.J. et al. 2020. The role of graphite addition on spark plasma sintered titanium nitride. , DOI: https://doi.org/10.1016/j.jmrt.2020.03.040
  • Description: Abstract: tComposites of titanium nitride reinforced with graphite were synthesized using sparkplasma sintering at 2000◦C. The effects of graphite addition on the microstructure, relativedensity, and mechanical properties of TiN ceramics matrix were examined. The investiga-tion was performed on TiN powder with varying graphite content (1–5 wt.%) for 8 h using anenergy ball milling equipment. Results show that TiN without and with graphite (TiN + 1 wt.%graphite) sintered at 2000◦C recorded sintered relative density of 96.7% and 97% respec-tively. Additionally, TiN with 3 wt.% graphite had a relative density of 98%. However, theshrinkage of TiN + 3 wt.% graphite was observed to be the lowest compared to other com-posites at the same sintering conditions. Microstructural analysis indicates that the grainof titanium nitride in the composite was very fine and continuous. Subsequently, a bimodalparticle sizes were observed when 5 wt.% graphite was dispersed in TiN. The highest Vickersmicrohardness of 23.5 GPa and fracture toughness of 6.5 MPa m1/2were achieved with com-posites reinforced with 3 wt.% graphite at milling period of 8 h. The combination of TEM/EDSand HRTEM/FFT show a single pattern of diffraction and consistency in interplanar distanceobtained from X-ray diffractometry of the milled sample. There is a clear coherence interfacebetween the phases.
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