Full Analysis of Sierra Leone Bauxite and Possibilities of Bauxite Residue Filtration

Dobra, Gheorghe; Kiselev, A. O.; Filipescu, Laurentiu; Alistarh, Vicol; Anghelovici, Nicolae; Iliev, S.

doi:10.17516/1999-494x-2016-9-5-643-656

Cited by 6 publications

(11 citation statements)

References 6 publications

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“…and heavy metal content and respectively, for assessment of the acute toxicity/irritation. All the data concerning this particular type of bauxite residue, representing 10% of the entire stockpiled material, were presented in the papers [1,12]. The second type of sampled bauxite residue, representing 90% of the entire stockpiled material, was used for studies on the deep changing of bauxite residue chemical properties and evaluation of the minimal required treatments for using it as remediation adjuvant for acid soils or for converting the bauxite residue into commercial products.…”

Section: Methods and Analysesmentioning

confidence: 99%

“…Also, by amending the regular doses of bauxite residue, organic compost and mineral fertilizers according the Table 10, a lot of changes were yielded in soil chemistry, as well as in its agrochemical properties (Table 11, 12).…”

Section: Chemical Analysis and Properties Of The Soil From Experimentmentioning

confidence: 99%

“…Thus, the total exchangeable bases (SB), degree of bases saturation (V Ah , %) and the total capacity of cationic exchange were substantially raised, and the hydrolytic acidity recorded earnest diminutions (Table 11, 12). Moreover, the total soluble salts content (TSS) dropped below the critical level of 100 mg/100 g (Table 11).…”

Section: Chemical Analysis and Properties Of The Soil From Experimentmentioning

confidence: 99%

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Bauxite Residue Safety Disposal and Possibilities to Further Utilization. Part 1. Acid Soils Remediation

Dobra¹,

Filipescu²,

Anghelovici³

et al. 2017

J. Sib. Fed. Univ. Chem.

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This paper is presenting the investigations concerning a new approach in acid soil remediation by deep reshaping the land surface layer, in order to change its agrochemical composition and properties. IntroductionAfter 2009 retrofit of the landfill site at Vimetco Alum SA Tulcea refinery and significant improvements brought by switching from bauxite residue sludge lagoon impoundment to deep thickening and disposal in dry state, the dried bauxite residue disposal site met the terms of main EU directives recommendation regarding environmental protection. During the retrofit of landfill site and afterward, many noteworthy works were carried out for the sake of investment consolidation [1]. Thus, the environmental risks have been considerably reduced compared to previous applied technology for dumping the bauxite residue, and the disposal site environmental impact on the surrounding agricultural area is not significant anymore.Since 2011 Vimetco Alum SA Tulcea was using predominantly the bauxite originating from Sierra Leone. From thenceforth, the factory accumulated a good experience in processing this type of bauxite and started some projects carried out in its laboratory or in cooperation with other Romanian research -8 -Gheorghe Dobra, Laurentiu Filipescu… Bauxite Residue Safety Disposal and Possibilities to Further Utilization… institutes, trying to find new applications for the well characterized bauxite residue (bauxite residue chemical/mineralogical analysis and physical properties, new measurements of radioactivity, heavy metal content, composition and properties of the minimal processed bauxite residue at the disposal site location, and toxicity/irritation and dermal corrosivity thresholds) [1]. Many studies underlined that the bauxite residue application to any soil is very effective for reducing the phosphorous leaching, improving the pasture growth, ameliorating the soil acidity, increasing the plant metal sorption and decreasing the soluble metals concentration, and above all, the bauxite residue reduces the heavy metals availability [2][3][4][5][6][7]. But, the acid soil rehabilitation with bauxite residue is not just a simple problem of mixing and dispersing. The simple addition of bauxite residue to soils involves increases in pH, in total dissolved solids (TDS), in dissolved organic compounds (DOC), as well as some raises in the concentrations of oxy-anion-forming heavy metals in the soil solutions. The extent of these changes depends highly on the final mixture pH and also, on the soil natural or induced buffering capacity. It should be avoided the pH values above 8.5-9.0 (promoting some larger increases in the concentrations of aluminium, vanadium and arsenic), as well as the low organic carbon and high clay content (promoting the heavy metal mobilization). This is the reason for the bauxite residue association with other materials rich in organic carbon [1][2][3][4][5][6][7].Researches concerning the uses of bauxite residue in agriculture could be classified according to their disclosed specific...

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Section: Methods and Analysesmentioning

confidence: 99%

Section: Chemical Analysis and Properties Of The Soil From Experimentmentioning

confidence: 99%

Section: Chemical Analysis and Properties Of The Soil From Experimentmentioning

confidence: 99%

See 1 more Smart Citation

Bauxite Residue Safety Disposal and Possibilities to Further Utilization. Part 1. Acid Soils Remediation

Dobra¹,

Filipescu²,

Anghelovici³

et al. 2017

J. Sib. Fed. Univ. Chem.

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“…The lanthanides and (additionally) scandium and yttrium content in a fluid and solid phases from the aluminum hydroxide production cycle were measured after the onset of all research facilities to develop of a technology for obtaining dry, milled and classified aluminum hydroxide. Representative samples of bauxite concentrated and spent Bayer liquors and different sorts of aluminum hydroxide dried, milled and classified were collected in many rounds for different purposes [65,66]. From this large number of samples, there were selected two sets of data representing the best results concerning: the mineralogy of both Sierra Leone bauxite (BA1, BA2) and bauxite residues (BR1, BR2), the composition of concentrated Bayer liquor and, impurity concentration in some of in the commercial grades of aluminum hydroxide.…”

Section: Experimental Part Materialsmentioning

confidence: 99%

“…Bauxite from Sierra Leone is still a little-known raw material for the Bayer's alumina production, even if the first information about its composition and petrography were published many years ago [61,62]. In the last 10 years, only a few papers were published by Alum SA, Tulcea, Romania, mainly related to the use of this bauxite as raw material for the production of Bayer alumina [63][64][65][66]. For a careful analysis of the minor elements from materials with complex mineralogy, such as the bauxite and bauxite residue, the literature recommends two ways of preliminary treatment: alkali fusion followed by the acid digestion [67][68][69], respectively, the acid baking followed by extraction with water [70][71][72].…”

Section: Introductionmentioning

confidence: 99%

Lanthanides as impurities in the Bayer production cycle of the aluminum hydroxide from Sierra Leone bauxite

Kim¹,

Dobra²,

Isopescu³

et al. 2022

RJEEC

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This paper is describing a careful study of the content and distribution of rare elements in the fluid and solid phases involved in dry and classified aluminum hydroxide production through the Bayer process at Alum SA, Tulcea, Romania. The source of rare elements in the Bayer process is the bauxite from Sierra Leone, a particular type of aluminous goethite-lateritic bauxite, not fully studied yet. Rare earth elements are fairly abundant in nature, but their distribution is very large, encompassing hundreds of types of minerals where the rare element appears as minor crystalline and amorphous compounds, solid solutions, or as ions adsorbed on the surface of common natural rocks. This study data show that Sierra Leone bauxite has only a small content in rare elements. Mainly, only the scandium and cerium concentrations (44.84 mg/kg and 11.49 mg/kg in bauxite residue) may reach the expected values required for eventual valorization. On the Bayer cycle, the rare metals enter with bauxite and concentrate in bauxite residues. Solubility of the rare element compounds in the Bayer process fluid phases is close to zero. In the final product, the aluminum hydroxide dried, milled and classified grades, the rare metals appear only as occlusion contaminants.

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Determination of the iron oxide content in bauxite: comparing ICP-OES with UV–VIS and volumetric analysis

Ostojić¹,

Lazić

Zeljković

2020

Chem. Pap.

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Full Analysis of Sierra Leone Bauxite and Possibilities of Bauxite Residue Filtration

Cited by 6 publications

References 6 publications

Bauxite Residue Safety Disposal and Possibilities to Further Utilization. Part 1. Acid Soils Remediation

Bauxite Residue Safety Disposal and Possibilities to Further Utilization. Part 1. Acid Soils Remediation

Lanthanides as impurities in the Bayer production cycle of the aluminum hydroxide from Sierra Leone bauxite

Determination of the iron oxide content in bauxite: comparing ICP-OES with UV–VIS and volumetric analysis

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