Chemical Characterization of Iron Oxide Precipitates From Wetlands Constructed to Treat Polluted Mine Drainage

Fish, Caryl L.; Partezana, J.M.; Hedin, Robert S.

doi:10.21000/jasmr96010541

Cited by 14 publications

(9 citation statements)

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“…The endpoint of pH neutralisation and the molar ratio between iron and other pollutants are the key factors that control the rate and extent of sorption/co-precipitation processes. For example, the iron precipitates as goethite, mainly when the endpoint of pH neutralisation is lower than 5,0 (Fish et al, 1996) with minimal co-precipitation of silica and gypsum. The generated rich-in-iron-sludge (the content of iron oxides is higher than 50%) is with satisfactory pigmentary characteristics, and it is used as a raw material for the production of mineral pigments for industry (Hedin et al, 2002).…”

Section: Paragoethite Processmentioning

confidence: 99%

Iron Removal From Laden Bioleaching Solution by Processes of Solvent Extraction and Magnetite Synthesis

Georgiev¹,

Nicolova²,

Spasova³

et al. 2023

SEPRM

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Laden leach solution, generated from bioleaching of pyrometallurgical copper slags with a mixed culture of moderately thermophilic bacteria in a bioreactor, contains several base metals (Cu, Co, Zn) and a very high concentration of iron (33,9 g/ L). Further processing of cobalt and zinc to the respective final products requires preparatory iron removal from the laden leach solution. The direct iron removal from that solution as goethite was unacceptable because of the significant co-precipitation of copper and cobalt from the solution. The main aim of this paper is to study magnetite (Fe3O4) synthesis as an approach for iron removal to a value-added product as a step of the processing of a laden solution generated due to the bioleaching of non-ferrous metals in a bioreactor. Ferrous iron oxidation to ferric state was efficient when the addition of H2O2 (30 %) was combined with maintaining the pH 3,1-3,3 with NaOH and air purging. Solvent extraction with 25 % D2EHPA and 7,5 % TBP dissolved in kerosene efficiently separated the dissolved iron and the base metals from the processed solution. However, in the presence of H2, the iron was stripped from the organic solvent with low acid consumption. The applied precise control of the chemical precipitation and oxidation processes at 50 degrees Celsius allowed the iron content (11,7 g/ L) in the stripping solution to be removed efficiently as magnetite (Fe3O4). Based on the chemical content of iron, copper and sulphur, the synthesised nanoparticles of magnetite could be applicable in many sectors (steel, chemical, and electronics).

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Section: Paragoethite Processmentioning

confidence: 99%

Iron Removal From Laden Bioleaching Solution by Processes of Solvent Extraction and Magnetite Synthesis

Georgiev¹,

Nicolova²,

Spasova³

et al. 2023

SEPRM

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Section: Paragoethite Processmentioning

confidence: 99%

Features of Vibration Crushing of Geological Samples of Material

Fedoskina,

Yerisov,

Fedoskin

2023

SEPRM

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An innovative method of vibro-impact grinding of geological samples, implemented in a vibrating jaw crusher with an inclined crushing chamber, is considered to obtain a product of -1 mm in one crushing cycle. The technique consisted in comparing the results of crushing quartzite and magnetite with a particle size of 60...80 mm according to the existing multi-stage technology using jaw and roller crushers, as well as the proposed single-stage technology using a vibrating jaw crusher. Three technological schemes for the preparation of samples of quartzite and magnetite were modelled with obtaining granulometric characteristics after each piece of equipment. The analysis of the results showed almost the same particle size distribution of the samples according to the multi-stage scheme: jaw crusher, screening -2mm, roller crusher, screening -1mm and single-stage: vibrating jaw crusher, screening -1mm. The output of the finished material was 80%. The studies substantiated the feasibility of creating a small-sized vibrating jaw crusher with a crushing ratio of i ≥ 100 for the preparation of geological samples, operating in an open cycle and replacing at least two pieces of crushing equipment, two screens and mounting elements, which significantly reduces the metal consumption of the structure, the occupied area and simplifies maintenance.

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“… CO 2 evolved when organic compounds that are oxidized and carbonate compounds are calcined;  SO 2 evolved when sulfur-containing compounds are calcined; and  H 2 O evolved during heat-induced changes in Fe oxyhydroxide compounds. X-ray diffraction has indicated that the primary crystalline form of Fe in the raw samples is goethite (FeOOH) (Fish et al, 1996). The amorphous phase is likely Fe hydroxide (Fe(OH) 3 ).…”

Section: Contributors To Loi Includementioning

confidence: 99%

“…The research was prompted by the observation that many Fe-precipitating systems have negligible effect on other water constituents (Hedin et al 1994a), suggesting that the Fe solids retained were relatively pure. The research determined that the Fe oxides that precipitate in passive systems can be pure enough to have market value, particularly as raw unfinished pigment (Fish et al, 1996). A method for producing saleable Fe oxide from mine drainage was developed and patented (Hedin 1999).…”

Section: Introductionmentioning

confidence: 99%

Sustainable Mine Drainage Treatment Through the Passive Production of Saleable Iron Oxide Solids

Hedin¹

2006

ASMR

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Iron is the most common metal contaminant of coal mine drainage. Its treatment creates a metal-rich sludge whose management accounts for a substantial portion of the total treatment costs. For decades, researchers have searched unsuccessfully for cost-mitigating uses for mine drainage sludge. This paper describes our progress in the development of a passive treatment process that yields iron oxide sludge that has valuable pigmentary characteristics. Samples of iron solids were collected from a variety of environments. All samples from chemical treatment systems were impure because of the coprecipitation of multiple chemical parameters. Only passive treatment systems yielded sludge pure enough to be considered for pigmentary applications. At several sites, the purity of the samples from passive systems was substantially decreased by the presence of alumino-silicate minerals introduced by inflows of surface water containing sediment. Mechanical and moderate chemical treatment, that was intended to accelerate iron oxidation without the precipitation of nontarget elements, caused the precipitation of calcium-containing minerals that lessened the pigment strength. Solids collected from passive systems where the pH ranged below 6 were pure, but were weak pigments. Saleable pigment-quality iron solids were produced from passive systems where sediment inflows were minimal and the pH was maintained between 6 and 7. A treatment system that produces saleable iron solids through passive treatment techniques has the potential to provide self-sustaining mine drainage treatment.

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Chemical Characterization of Iron Oxide Precipitates From Wetlands Constructed to Treat Polluted Mine Drainage

Cited by 14 publications

References 0 publications

Iron Removal From Laden Bioleaching Solution by Processes of Solvent Extraction and Magnetite Synthesis

Iron Removal From Laden Bioleaching Solution by Processes of Solvent Extraction and Magnetite Synthesis

Features of Vibration Crushing of Geological Samples of Material

Sustainable Mine Drainage Treatment Through the Passive Production of Saleable Iron Oxide Solids

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