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International Journal of Environment Science and Technology
Center for Environment and Energy Research and Studies (CEERS)
ISSN: 1735-1472 EISSN: 1735-1472
Vol. 11, No. 7, 2014, pp. 1989-1998
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Bioline Code: st14194
Full paper language: English
Document type: Research Article
Document available free of charge
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International Journal of Environment Science and Technology, Vol. 11, No. 7, 2014, pp. 1989-1998
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Optimization of sample preparation method of total sulphur measurement in mine tailings
Khan, A.H.; Shang, J.Q. & Alam, R.
Abstract
A sample preparation method of total sulphur
measurement of reactive mine tailings was optimized. The
total sulphur was measured by inductively coupled plasma
optical emission spectroscopy, and ultrasound technique
was used for sample digestion. The optimization process
was adopted by a combined approach of experimental
design and response surface methodology. The digestion
time, temperature and acid-oxidant combination (i.e.
effect of H2O2 with a fixed amount of acid mixture) were
investigated. A two-level and three-factor (23) full factorial
design of experiment was applied to identify the most
significant factors, and a central composite design was
used to optimize the digestion procedure. KZK-1, a sericite
schist, was selected as the certified reference material.
The optimum methodology at 95 % confidence level
(P < 0.05) was identified to be 10 min of digestion at
77 ℃, with a solution of 1 ml HNO3:1 ml HCl:1.35 ml
H2O2. This combination resulted in 100 % sulphur
recovery. The investigated method was verified by X-ray
diffraction analysis. The optimum digestion level was
applied to a reactive mine tailings, which achieved satisfactory
results with a percentage relative standard
deviation <3 %.
Keywords
Process optimization; Response surface methodology; Central composite design; Total sulphur analysis; ICP-OES; Ultrasound-assisted digestion
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