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Characterization of rice hull ash and its performance in turbidity removal from water

  • Authors: Adams, F. V. , Ikotun, B. D. , Patrick, D. O. , Mulaba-Bafubiandi, A. F.
  • Date: 2014
  • Subjects: Rice hull ash , Turbidity removal
  • Type: Article
  • Identifier: uj:4790 , http://hdl.handle.net/10210/12041
  • Description: This study characterizes the locally obtained samples of rice hull ash and investigates its performance on turbidity removal from water. Four samples of this material were studied, namely, unwashed parboiled rice hull ash (UPRHA), washed parboiled rice hull ash (WPRHA), unwashed unparboiled rice hull ash (UUPRHA), and washed unparboiled rice hull ash (WUPRHA). Scanning electron microscopy (SEM), x-ray diffractometer (XRD), and Fourier infrared spectroscopy (FTIR) were carried out to characterize these samples. A filtration process was carried out to investigate the effectiveness of the rice hull ash medium in removing water turbidity. The XRD results showed the silica, which is present in the ashes, to be cristobalite, quartz, and tridymite. The silica contents of the UUPRHA and WUPRHA were observed to be 77.10% and 98.24%, respectively, while those of UPRHA and WPRHA were 79.07% and 94.97%, respectively. The SEM images showed agglomeration of ash particles after the ashes were washed. The washed RHA samples showed improved pH, a good percentage of turbidity removal (<5 NTU) from water sample. Washing RHA with distilled water increased the efficiency of RHA in turbidity removal from water and regulated water pH to an acceptable range.
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Technological feasibility and cultural acceptability study of solar power systems for microwave assisted sandstone artisanal mining

  • Authors: Agwa-Ejon, J. F. , Mulaba-Bafubiandi, A. F. , Pretorius, J. H.
  • Date: 2015-08-06
  • Subjects: Artisinal mining - South Africa - QwaQwa , Sandstone - South Africa - QwaQwa , Microwave energy , Solar energy
  • Type: Article
  • Identifier: uj:5218 , http://hdl.handle.net/10210/14504
  • Description: This paper investigates the technical feasibility of microwave assisted artisanal mining in the production of Sandstone from QwaQwa in South Africa. It further discusses the cultural acceptability by the rural community of the synergetic application of the emerging technology (microwave energy) and the renewable resource (solar). Sandstone in QwaQwa, Free State is artisanally mined using chisels and hammers. This form of mining is extensively laborious and is normally accompanied by numerous casualties. The paper demonstrates the existence and the possible utilization of alternative methods including emerging technologies which are more productive, efficient, effective and sustainable. The solar energy systems are used to trigger the microwave magnetron which results into high energy microwave dosage. The dosage causes differential or selective heating on the rocks which culminate into rock breaking along the interfacial grain boundaries between the different constituting minerals. The data used in the analysis was collected by administering questionnaires to the artisanal mining community in QwaQwa and from observations made on site as well as desk top information obtained from secondary sources. The paper contributes to knowledge by drawing on the solar energy systems to generate the dosage required to trigger the microwave magnetron used to facilitate a more efficient and economical artisanal mining of sandstones. In conclusion the paper recommends to policy makers the application of microwave energy in mineral artisanal mining and processing instead of the manual chisel and hammer currently being utilized country wide. It then gives a detail analysis of the technical, scheduling and economic analysis of the sandstone artisanal mining in QwaQwa.
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Alkaline leaching of nickel bearing ammonium jarosite precipitate using KOH, NaOH and NH4OH in the presence of EDTA and Na2S

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