Recovering and recycling Hg from chlor-alkali plant wastewater sludge

Twidwell, L.G.; Thompson, R. J.

doi:10.1007/s11837-001-0155-z

Cited by 11 publications

(12 citation statements)

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“…To regenerate ferric chloride solution from the leaching solution by solvent extraction with these extractants, FeCl 2 must be oxidized to FeCl 3 . Since the oxidation reaction depends on the HCl concentration in the solution, 8) the control of HCl concentration is important.…”

Section: Introductionmentioning

confidence: 99%

Chemical Model of the FeCl3-HCl-H2O Solutions at 25°C

Lee

Ahn

2003

Mater. Trans.

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A chemical model was developed to calculate the equilibrium concentrations of chemical species in the FeCl 3 -HCl-H 2 O system at 25 C by using chemical equilibria, mass and charge balance equations. The activity coefficients of solutes and the activity of water were calculated with the Bromley equation. The interaction parameters for the individual chemical complexes, which were necessary to calculate the activity coefficients, were obtained from the reported interaction parameters between ions. By applying this model, the distribution of iron species with the electrolyte concentrations was obtained. In the experimental ranges of the ionic strength of solution up to 7.28 m, the experimental pH values were in good agreement with the predicted pH values.

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Section: Introductionmentioning

confidence: 99%

Chemical Model of the FeCl3-HCl-H2O Solutions at 25°C

Lee

Ahn

2003

Mater. Trans.

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“…Since a wide range of pH and reaction times were reported in the literature (Twidwell and Thompson 2001;Hummer et al 2006;Bussi et al 2010), the impact of these parameters on the effectiveness of oxidative leaching was investigated by conducting preliminary tests for determining the concentrations of the reagents. According to these preliminary results, the leaching tests for each reactive solution were conducted at an agitation rate of 120 rpm, pH=7.5, and a process time of 2 or 5 h for the NaOCl/NaCl and KI/I 2 solutions, respectively.…”

Section: Determination Of the Initial Mercury Concentrationmentioning

confidence: 99%

“…High hypochlorite concentration would cause the precipitation of Fe(OH) 3 if Fe powder were to be used as the reducing agent during cementation. This condition would have caused the elemental mercury, which was recovered during cementation, to dissolve back again, thus adversely affecting the cementation efficiency (Twidwell and Thompson 2001;Bussi et al 2010). The optimal leaching conditions for the 50 % pulverized mixture of glass + phosphorous powder from spent T8-T12 lamps were achieved by the central point tests that were conducted at a temperature of 50°C, a solid/ liquid ratio of 1/2 and at reactive solution concentrations of 0.5 M NaOCl/0.2 M NaCl (96 % mercury leaching efficiency) and 0.5 M KI/0.2 M I 2 (95 % mercury leaching efficiency).…”

Section: Leaching Experimentsmentioning

confidence: 99%

“…Therefore, oxidative leaching using sodium hypochlorite/sodium chloride (NaOCl/NaCl) and potassium iodide/ iodine (KI/I 2 ) was conducted as efficient methods to extract mercury as an Hg(II) complex (mercury tetrachloride, HgCl 4 2− , and HgI 4 2− ) as given by Eq. 1 (Twidwell and Thompson 2001) and Eq. 2 (Klasson et al 1998).…”

Section: Introductionmentioning

confidence: 99%

“…These oxidizing agents were generally used in mercury recovery from the process sludge in chlorinealkaline facilities (Twidwell and Thompson 2001) and from industrial wastes (Klasson et al 1998) with high mercury content. The recovery efficiencies were in the range of 85 to 99 %.…”

Section: Introductionmentioning

confidence: 99%

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Recovery of Mercury from Spent Fluorescent Lamps via Oxidative Leaching and Cementation

Coşkun

Civelekoğlu

2015

Water Air Soil Pollut

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In this work, the recovery of mercury from spent fluorescent lamps by oxidative leaching followed by cementation process was studied. Two different reactive solutions (NaOCl/NaCl and KI/I 2 ) during oxidative leaching were investigated whereas at the cementation process, metallic powders of iron (Fe), copper (Cu), and zinc (Zn) were used as reducing agents to capture mercury in solid phase. Mercury could be transferred to the solution with an efficiency of 96 % from the spent lamp samples through the NaOCl/NaCl reagent. The optimal leaching conditions were determined as 2-h contact time, 120 rpm agitation speed, pH 7.5, and 50°C of temperature. The reducing agent, Zn, provided 99 % of the cementation. The optimal process conditions were observed to be as 5-min contact time, pH 1, and 5 g L −1 of reducing agent concentration. This combined approach appears to be technically effective for the recovery of mercury from spent fluorescent lamps.

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Reaction of Mercury(0) with the I₂ Adduct of Tetraphenyldithioimidodiphosphinic Acid (SPPh₂)₂NH (HL) − Crystal Structures of [Hg(HL)I₂] and HgL₂

et al. 2004

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The complex [Hg(HL)I2] (1) has been synthesised by reacting liquid Hg(0) in Et2O under mild reaction conditions with the I2 adduct of HL, HL·I2, while HgL2 (2) has been obtained from the reaction of compound 1 with HL in CH3CN. A single‐crystal X‐ray investigation of 1 shows four independent molecules in the asymmetric unit, each of which contains an HgII ion coordinated to two iodine atoms and two sulfur atoms of one bidentate neutral ligand in a distorted tetrahedral coordination geometry. Compound 2 consists of two anionic ligands coordinated to an HgII ion, which again displays a distorted tetrahedral coordination sphere. The reaction of 2 with HI (55 wt.‐% in water) affords [Hg(HL)2](I)2 (3). Compounds 1, 2, and 3 have been characterised by FT‐IR and 31P NMR spectroscopy. Density functional calculations suggest that compound 3 should feature a distorted tetrahedral coordination around the metal centre, with unequal Hg−S bond lengths. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)

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Recovering and recycling Hg from chlor-alkali plant wastewater sludge

Cited by 11 publications

References 0 publications

Chemical Model of the FeCl<SUB>3</SUB>-HCl-H<SUB>2</SUB>O Solutions at 25°C

Chemical Model of the FeCl<SUB>3</SUB>-HCl-H<SUB>2</SUB>O Solutions at 25°C

Recovery of Mercury from Spent Fluorescent Lamps via Oxidative Leaching and Cementation

Reaction of Mercury(0) with the I₂ Adduct of Tetraphenyldithioimidodiphosphinic Acid (SPPh₂)₂NH (HL) − Crystal Structures of [Hg(HL)I₂] and HgL₂

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Recovering and recycling Hg from chlor-alkali plant wastewater sludge

Cited by 11 publications

References 0 publications

Chemical Model of the FeCl<SUB>3</SUB>-HCl-H<SUB>2</SUB>O Solutions at 25&deg;C

Chemical Model of the FeCl<SUB>3</SUB>-HCl-H<SUB>2</SUB>O Solutions at 25&deg;C

Recovery of Mercury from Spent Fluorescent Lamps via Oxidative Leaching and Cementation

Reaction of Mercury(0) with the I2 Adduct of Tetraphenyldithioimidodiphosphinic Acid (SPPh2)2NH (HL) − Crystal Structures of [Hg(HL)I2] and HgL2

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Chemical Model of the FeCl<SUB>3</SUB>-HCl-H<SUB>2</SUB>O Solutions at 25°C

Chemical Model of the FeCl<SUB>3</SUB>-HCl-H<SUB>2</SUB>O Solutions at 25°C

Reaction of Mercury(0) with the I₂ Adduct of Tetraphenyldithioimidodiphosphinic Acid (SPPh₂)₂NH (HL) − Crystal Structures of [Hg(HL)I₂] and HgL₂