Solubility of KFe3(CrO4)2(OH)6 at 4 to 35°C

Baron, Dirk; Palmer, Carl D.

doi:10.1016/0016-7037(96)00206-2

Cited by 49 publications

(18 citation statements)

References 18 publications

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“…Sorbent minerals used for this experiment were synthesized according to several procedures [13,17,[52][53][54][55][56][57]. No sample of schwertmannite with co-precipitated arsenic was synthesized, instead, a natural sample form the acid mine drainage of Monte Romero mine (Iberian Pyrite Belt, Spain) was used [58].…”

Section: Methodsmentioning

confidence: 99%

“…At pH ~ 3.7, a slight increase in arsenic (7 µg/L), iron (0.96 mg/L), and sulphate (2.5 g/L) concentrations can be interpreted as a minor dissolution that ends when the system normalizes around pH 4. In order to understand the low TLC (~0.81 wt %) compared with values given in the literature (~10 wt %) [56,65], it should be considered that under the Regenspurg method a quick precipitation process could affect the morphology of the grains and subsequently the development of surface area [54]. …”

Section: Arsenic Release From Schwertmannitementioning

confidence: 99%

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Liberation of Adsorbed and Co-Precipitated Arsenic from Jarosite, Schwertmannite, Ferrihydrite, and Goethite in Seawater

2014

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Sea level rise is able to change the geochemical conditions in coastal systems. In these environments, transport of contaminants can be controlled by the stability and adsorption capacity of iron oxides. The behavior of adsorbed and co-precipitated arsenic in jarosite, schwertmannite, ferrihydrite, and goethite in sea water (common secondary minerals in coastal tailings) was investigated. The aim of the investigation was to establish As retention and transport under a marine flood scenario, which may occur due to climate change. Natural and synthetic minerals with co-precipitated and adsorbed As were contacted with seawater for 25 days. During this period As, Fe, Cl, SO 4 , and pH levels were constantly measured. The larger retention capability of samples with co-precipitated As, in relation with adsorbed As samples, reflects the different kinetics between diffusion, dissolution, and surface exchange processes. Ferrihydrite and schwertmannite showed good results in retaining arsenic, although schwertmannite holding capacity was enhanced due its buffering capacity, which prevented reductive dissolution throughout the experiment. Arsenic desorption from goethite could be understood in terms of ion exchange between oxides and electrolytes, due to the charge difference generated by a low point-of-zero-charge and the change in stability of surface complexes between synthesis conditions and natural media. OPEN ACCESSMinerals 2014, 4 604

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Section: Methodsmentioning

confidence: 99%

Section: Arsenic Release From Schwertmannitementioning

confidence: 99%

Liberation of Adsorbed and Co-Precipitated Arsenic from Jarosite, Schwertmannite, Ferrihydrite, and Goethite in Seawater

2014

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“…Otherwise, different groups of peaks would appear for each phase, which did not happen. 22 Nature of the decomposition reaction I n o r d e r t o d e t e r m i n e t h e n a t u r e o f t h e decomposition reaction, samples of the solid solution KFe 3 (SO 4 ) 2−x (CrO 4 ) x (OH) 6 were taken and treated with Ca(OH) 2 ; they were analyzed for K + and CrO 4 2− by AAS, and for SO 4 2− by gravimetry, at different times. The solid residues were characterized by SEM-EDS.…”

Section: Synthesis and Characterizationmentioning

confidence: 99%

“…The substitution of H 3 O and Na in site A significantly increases the jarosite solubility compared to jarosite with K, while the substitution of chromate by sulfate decreases the solubility of potassium jarosite. 5,22 The most widespread method used to mitigate acid effluents is an active treatment process involving addition of a chemical-neutralizing agent, being lime the most common used agent. Addition of lime to acid mine drainage (AMD) raises its pH, accelerates the rate of chemical oxidation of ferrous iron and causes precipitation of metals present as hydroxides and carbonates.…”

Section: Introductionmentioning

confidence: 99%

Kinetic Analysis of the Decomposition of the KFe₃(SO₄)_2-x(CrO₄)_x(OH)₆Jarosite Solid Solution in Ca(OH)₂Medium

Mireles¹,

Reyes²,

Flores³

et al. 2015

Journal of the Brazilian Chemical Society

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The decomposition of the solid solution of potassium jarosite with chromium(VI) in Ca(OH) 2 media was studied in the present work. According to experimental results, the incorporation of CrO 4 2− into the crystal structure of jarosite resulted in a solid solution with the following approximate formula: [K 0.86 , and E a = 51.56 kJ mol −1 . The CrO 4 2− diffusion is slower compared to that of sulfate, a slight amount of chromate is adsorbed in the layer of the solid residue consisting on Fe(OH) 3 . Finally, the equations that satisfactorily describe the reaction process were established from the data obtained.

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“…[7] More recently, studies have detailed the solubility of the chromate analogue and have demonstrated that an ideal solid solution series exists between KFe 3 (SO 4 ) 2 (OH) 6 and KFe 3 (CrO 4 ) 2 (OH) 6 . [8,9] The behavior of Cr(III) during jarosite precipitation is less well defined, although the Cr(III) analogues of both hydronium jarosite (H 3 OCr 3 (SO 4 ) 2 (OH) 6 ) and potassium jarosite (KCr 3 (SO 4 ) 2 (OH) 6 ) have been synthesized from chromium sulfate solutions at 300 °C. [10,11] Furthermore, Kolitsch and Pring [12] have reported extensive Cr(III) substitutions in some naturally occurring phosphate and arsenate analogues of jarosite-type compounds.…”

Section: Introductionmentioning

confidence: 99%

Factors affecting the precipitation of chromium(III) in jarosite-type compounds

Dutrizac,

Chen

2005

Metall Mater Trans B

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Jarosite precipitation is a useful means of stabilizing toxic species, and accordingly, the factors affecting the precipitation of chromium(III) in jarosite-type compounds was systematically investigated in a series of laboratory experiments. Although end-member Cr(III) analogues of jarosite-type compounds could not be precipitated at temperatures Ͻ100 °C, several percent Cr(III) substitution for Fe(III) in potassium jarosite and sodium jarosite was observed. However, at temperatures Ͼ200 °C, the Cr(III) analogue of potassium jarosite (KCr 3 (SO 4 ) 2 (OH) 6 ) is readily precipitated. The Cr(III) analogue has the structure characteristic of jarosite-type compounds, with a ϭ 7.23 Ϯ 0.02Å and c ϭ 17.02 Ϯ 0.02 Å. The well-crystallized material typically contains (wt pct): ϳ7K, ϳ25Cr, and ϳ41SO 4 . The composition suggests the partial substitution of hydronium ion for potassium and some chromium vacancies in the structure. The formation of the Cr(III) analogue is promoted by increasing temperatures, retention times, and Cr(III) concentrations. Increasing acid concentrations reduce the amount of product formed but suppress the undesirable precipitation of amorphous phases. Although increasing K 2 SO 4 concentrations result in a greater mass of precipitate, the products formed from concentrated K 2 SO 4 solutions are contaminated with an amorphous phase. In fact, the overall results suggest that an amorphous phase precipitates initially and that the Cr(III) analogue of potassium jarosite forms by the recrystallization, or the dissolution-reprecipitation, of the amorphous phase. R3 m

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Solubility of KFe3(CrO4)2(OH)6 at 4 to 35°C

Cited by 49 publications

References 18 publications

Liberation of Adsorbed and Co-Precipitated Arsenic from Jarosite, Schwertmannite, Ferrihydrite, and Goethite in Seawater

Liberation of Adsorbed and Co-Precipitated Arsenic from Jarosite, Schwertmannite, Ferrihydrite, and Goethite in Seawater

Kinetic Analysis of the Decomposition of the KFe₃(SO₄)_2-x(CrO₄)_x(OH)₆Jarosite Solid Solution in Ca(OH)₂Medium

Factors affecting the precipitation of chromium(III) in jarosite-type compounds

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Solubility of KFe3(CrO4)2(OH)6 at 4 to 35°C

Cited by 49 publications

References 18 publications

Liberation of Adsorbed and Co-Precipitated Arsenic from Jarosite, Schwertmannite, Ferrihydrite, and Goethite in Seawater

Liberation of Adsorbed and Co-Precipitated Arsenic from Jarosite, Schwertmannite, Ferrihydrite, and Goethite in Seawater

Kinetic Analysis of the Decomposition of the KFe3(SO4)2-x(CrO4)x(OH)6Jarosite Solid Solution in Ca(OH)2Medium

Factors affecting the precipitation of chromium(III) in jarosite-type compounds

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Kinetic Analysis of the Decomposition of the KFe₃(SO₄)_2-x(CrO₄)_x(OH)₆Jarosite Solid Solution in Ca(OH)₂Medium