Comparative testing between conventional and microencapsulation approaches in controlling pyrite oxidation

Vandiviere, M. M.; Evangelou, V. P.

doi:10.1016/s0375-6742(98)00030-2

Cited by 36 publications

(31 citation statements)

References 8 publications

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“…Once a coating is established on the surface of pyrite, oxidation of pyrite and production of AMD would be prevented. There are reports on the application of silicate (Zhang and Evangelou 1998), phosphate (Vandiviere and Evangelou 1998;Evangelou 2001) and 1, 3-benzenediamidoethanethiol (Matlock et al 2003) as coating materials. Among these coating approaches, silica coating seems to be superior to other methods, because silica coatings are relatively water-stable solids at circumneutral pH, are more resistant to acidic surroundings, and sustain the inhibition of AMD production for several years (Zhang and Evangelou 1998).…”

Section: Introductionmentioning

confidence: 99%

Experimental study on prevention of acid mine drainage by silica coating of pyrite waste rocks with amorphous silica solution

et al. 2010

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Acid mine drainage (AMD) is a widespread environmental problem associated with working and abandoned mining operations. It results from the microbial oxidation of pyrite in the presence of water and air, affording an acidic solution that contains toxic metal ions. Pyrite microencapsulation, utilizing silica coating, is a novel approach for controlling AMD that has been shown to be very effective in controlling pyrite oxidation. The roles of the solution pH and silica concentration in the formation mechanism for the AMD-preventing coating were investigated. A silica coating can be formed from silica solution at pH 7, at which the amount of Fe eluted from pyrite into the solution is small. No coating was formed at other pH values, and the amounts of eluted Fe were larger than at pH 7, especially at pH 11. The silica coating forms from 2,500 to 5,000 mg/L silica solutions, but not from 0 or 1,000 mg/L silica solutions. The coating formation rate was slower in the 2,500 mg/L silica solution than in the 5,000 mg/L silica solution. The formation of silica coating on pyrite surfaces depends on three main steps: formation of Fe(OH) 3 on the surface of pyrite, reaction between Fe(OH) 3 and silicate in the solution on the pyrite surface, and growth of the silica layer on the first layer of silica. The best pH condition to enable these steps was around 7, and the silica coating formation rate can be controlled by the concentration of silica.

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Section: Introductionmentioning

confidence: 99%

Experimental study on prevention of acid mine drainage by silica coating of pyrite waste rocks with amorphous silica solution

et al. 2010

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“…These authors propose that in near neutral and alkaline environments, HCO 3 À and CO 3 2À react with pyrite surface and form some weak Fe-carbonate complexes which accelerate non-microbial pyrite oxidation rate. Vandiviere and Evangelou (1998) and Evangelou (2001) used other alkaline reagents to study the pyrite microencapsulation process. These authors propose the addition of a solution composed of hydrogen peroxide (H 2 O 2 ) and sodium acetate (NaOAc) to a pyritic waste.…”

Section: Introductionmentioning

confidence: 99%

The iron-coating role on the oxidation kinetics of a pyritic sludge doped with fly ash

Pérez‐López

Cama

Nieto

et al. 2007

Geochimica et Cosmochimica Acta

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“…24) The gel retains the heavy metals, and is covered with particles of mine waste to disturb the contact of the waste with water and oxygen, which is a similar phenomenon to silica coating reported in previous pa- pers. [25][26][27] Additionally, the increase in pH permits the reduction of catalytic bacterial activity and reduces the rate of oxidation in the mining residue. It is considered that these phenomena inhibit the oxidation and dissolution of the sulphuric minerals.…”

Section: àmentioning

confidence: 99%

Stabilization of Mine Waste Using Paper Sludge Ash under Laboratory Condition

2007

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The leaching of potentially toxic elements or the generation of acidity from mine waste often creates significant environmental pollution. A great deal of research has been undertaken to find an effective solution to the problem of acid mine drainage. An attractive solution has been proposed, not only efficient but also economical, as it uses another waste material. The objective of this study was to investigate the feasibility of stabilizing acidic mine waste using alkaline industrial waste, paper sludge ash, produced by the pulp and paper industry, under laboratory conditions. By mixing mine waste with paper sludge ash (the weight ratio of mine waste to paper sludge ash is 10: 4), the eluted solution became neutral, and the concentrations of almost all metals dropped below the Japanese effluent standard. The inhibition of acid mine drainage with addition of PSA is sustainable. Although Radish sprouts did not grow on mine waste, they could be grown on the waste mixed with paper sludge ash. These results suggest that it is possible to use paper sludge ash for afforestation of a mine waste site.

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Comparative testing between conventional and microencapsulation approaches in controlling pyrite oxidation

Cited by 36 publications

References 8 publications

Experimental study on prevention of acid mine drainage by silica coating of pyrite waste rocks with amorphous silica solution

Experimental study on prevention of acid mine drainage by silica coating of pyrite waste rocks with amorphous silica solution

The iron-coating role on the oxidation kinetics of a pyritic sludge doped with fly ash

Stabilization of Mine Waste Using Paper Sludge Ash under Laboratory Condition

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