| 1. |
- Hoseinian, Fatemeh Sadat, et al.
(author)
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Ion flotation for removal of Ni(II) and Zn(II) ions from wastewaters
- 2015
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In: International Journal of Mineral Processing. - : Elsevier BV. - 0301-7516 .- 1879-3525. ; 143, s. 131-137
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Journal article (peer-reviewed)abstract
- Ion flotation was applied to Ni(II) and Zn(II) cation removal from low concentration synthetic wastewaters. Ethylhexadecyldimethylammonium bromide (EHDABr) and sodium dodecyl sulfate (SDS) were used as collectors and Dowfroth250 and methyl isobutyl carbonyl (MIBC) as frothers. The effective parameters were investigated by the experimental design performed by DX7 software. In this regard, a two-level factorial method was used, and sixteen experiments including 6-level variables were designed. In the first step, the tests were conducted in a Hallimond tube. It was concluded from test results that the optimum conditions for the removal of Ni(II) and Zn(II) ions by initial concentrations of 10. ppm were: pH = 3, SDS = 300. ppm, Dowfroth250 = 90. ppm and air flow rate = 1.8. ml/min. In the second step, optimal results from the first step were evaluated in a mechanical flotation cell. In optimal conditions, the recovery of Ni(II) and Zn(II) ions were 88% and 92%, respectively at 60. min. This study showed that the use of ion flotation is a very effective method for Ni(II) and Zn(II) ion removal from industrial wastewaters. The flotation time in achieving an optimum recovery of Zn(II) ions is shorter than that for Ni(II) ions.
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| 2. |
- Javadi Nooshabadi, Alireza, et al.
(author)
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Formation of hydrogen peroxide by pyrite and its influence on flotation
- 2013
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In: Minerals Engineering. - : Elsevier BV. - 0892-6875 .- 1872-9444. ; 49, s. 128-134
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Journal article (peer-reviewed)abstract
- Formation of hydrogen peroxide (H2O2), an oxidizing agent stronger than oxygen, by pyrite (FeS2), the most abundant metal sulphide on Earth, during grinding was investigated. It was found that pyrite generated H2O2 in pulp liquid during wet grinding and also the solids when placed in water immediately after dry grinding. Type of grinding medium on formation of hydrogen peroxide revealed that the mild steel produced more H2O2 than stainless steel grinding medium, where Fe2+ and/or Fe3+ ions played a key role in producing higher amounts of H2O2. The effect of grinding atmosphere of air and N2 gas showed that nitrogen environment free from oxygen generated more H2O2 than air atmosphere suggesting that the oxygen in hydrogen peroxide is derived from water molecules. In addition, the solids after dry grinding producing more H2O2 than wet grinding indicate the role of pyrite surface or its catalytic activity in producing H2O2 from water. This study highlights the necessity of relooking into the electrochemical and/or galvanic interaction mechanisms between the grinding medium and pyrite in terms of its flotation behaviour.
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