Measurement and evaluation of natural radioactivity in phosphogypsum in industrial areas from Romania

Calin, Marian Romeo; Rădulescu, Ileana

doi:10.1007/s10967-015-3970-3

Cited by 21 publications

(13 citation statements)

References 13 publications

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“…However, few researchers have investigated the preparation of α-HH from PG using hydrothermal autoclave method. In those studies, PG is not used due to the weak radioactivity and complex impurity components [16,17]. Therefore, preparation of high-strength α-HH from PG would have broad market potential and environmental benefits.…”

Section: Introductionmentioning

confidence: 99%

Facile preparation of high-strength α-CaSO4·0.5H2O regulated by maleic acid from phosphogypsum: experimental and molecular dynamics simulation studies

et al. 2020

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Crystal modifier is a significant factor in preparation of α-hemihydrate gypsum (α-HH) from phosphogypsum (PG). The influence of maleic acid, reaction temperature, time, and solid-liquid ratio on the preparation of high-strength α-HH from PG was systematically studied herein. The optimum condition for α-HH prepared by hydrothermal autoclave method was pH of 4, temperature of 140 °C for 2.0 h with solid-liquid ratio of 4:5. Crystal modifier of maleic acid can effectively regulated the crystal morphology of α-HH. SEM-EDS and FTIR analysis suggested that maleic acid could preferentially absorbed on the top face of α-HH crystals that decreased the growth rate of α-HH along the c-axis, resulting in the morphology of α-HH crystals transformed to hexagonal prisms, and the regulatory mechanism was estimated by molecular dynamics (MD). When maleic acid (0.1%) was added, the obtained α-HH showed aspect ratio of 1.2, and the flexural and compressive strength of the hardened α-HH could reach to 14.79 and 46.24 MPa, respectively. All of these results will help to design long-term effectiveness of phosphogypsum recycling strategies.

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Section: Introductionmentioning

confidence: 99%

Facile preparation of high-strength α-CaSO4·0.5H2O regulated by maleic acid from phosphogypsum: experimental and molecular dynamics simulation studies

et al. 2020

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“…The activity concentrations of 228 Ra, a 232 Th decay product, were lower than the detection limit. Concerning the 226 Ra activities, lower values for PG were reported for Romania (444-544 Bq kg -1 ) [3], Syria (318 ± 50 Bq kg -1 ) [43], Spain (South of Huelva-278-662 Bq kg −1 ) [44] and Greece (462 Bq kg -1 ) [45]. On the other hand, higher 226Ra activity concentrations values were reported for PG from Florida (500-1200 Bq kg -1 ), Morocco (500-1200 Bq kg -1 ) and Israel (500-1200 Bq kg -1 ) [46].The dark grey aggregates, rich in bassanite, with traces of Ti oxide, have high activities of 226 Ra (5385 ± 473 Bq kg -1 2302 Bq kg -1 ).…”

Section: Natural Radioactivitymentioning

confidence: 83%

“…The PG, the insoluble by-product resulting from the sulfuric acid attack (wet chemical treatment) of the phosphate rock to produce phosphoric acid, has associated high activities of natural radionuclides from U and Th series [1,2] and is designated as a TENORM. This by-product is usually deposited in dumps and stacks of very large volume and surface representing a great danger to the environment [3].…”

Section: Introductionmentioning

confidence: 99%

“…PG stockpiles contain two main types of mineral phases: a) the original materials which were not modified during acidification and b) minerals formed during acidification. The majority of minerals (up to 95%) belong to the second group, which is formed mainly of bassanite and gypsum [3,6]. High contents of sodium fluorosilicate have also been reported [7].…”

Section: Introductionmentioning

confidence: 99%

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Distribution of Natural Radionuclides, Rare Earth Elements, Metals and Metalloids in a Phosphogypsum Stockpile

Madruga¹,

Prudêncio²,

Corisco³

et al. 2019

Int J Waste Resour

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A first detailed study of phosphogypsum (PG) from a stockpile in Barreiro (Portugal) was performed aiming for a better characterization of this industrial waste deposit, considering its enhanced content in natural radionuclides and toxic metals, making it a potential contamination source to the Tejo estuary. Whole samples and aggregates of these wastes resulting from phosphate industries were analysed by neutron activation, gamma-spectrometry, X-ray diffraction and scanning electron microscopy. This work clearly shows that a significant chemical heterogeneity in the PG occurs due to the existence of aggregates with different compositions randomly distributed. Among these aggregates, the dark grey ones have high concentrations of Sc, Cr, Zn, Ga, Ba, REE, Ta, W, Th and U and the highest concentrations of 226 Ra and 210 Pb. The separation of these dark aggregates prior to any application of the PG would lead to a safer reuse of these wastes. The chemical patterns, including the REE distribution with a significant negative Ce anomaly, found in PG, are certainly related with the geochemical signatures of the phosphate rocks used as raw material. This PG stockpile may play a significant role as a radioactive source in the Tejo estuarine environment.

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“…The remaining (85%) of world PG production is discarded without a treatment. Usually, this by-product is put away in a large stockpile open for the weathering processes, occupying a large land area and resulting in dangerous damage to the environment, such as radioactive and chemical contaminations [7,8]. Phosphogypsum has mainly consisted of calcium sulfate dehydrates (CaSO 4 .2H 2 O).…”

Section: Introductionmentioning

confidence: 99%

(Polyphenyl Sulfone - Polyether Sulfone) Blending to Performance Flat Sheet Membrane to Remove Some Heavy and Radioactive Elements from Phosphogypsum Waste

Rashid

Alkadir²,

Jalhoom³

et al. 2021

ETJ

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In this research, the traditional version of the phase inversion method was used to fabricate a flat sheet of a blended membrane. The method was involved using a polymer that blends polyether sulfone (PES) varied proportions (0,3,4 and 5 wt.%), and polyphenyl sulfone (PPSU) was 20wt%. It was found that with the addition of PES, the membrane properties increased, the best properties were with 4%wt. The ratio was chosen PES 4wt% to study the effect of time, temperature, and pressure on the rejection of heavy and radioactive elements. The increase in the porosity was with the addition of 4% PES. The rejection of heavy and radioactive elements for thUF membrane increases with increasing of the operating pressure and time. While by increasing the temperature, the rejection of heavy and radioactive elements for thUF membrane decreased. The rejection of K, Th, and Pb are higher than other elements, the order of the rejection is K˃Th˃Pb˃U˃Cd˃Zn˃Cu>Ni.

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Measurement and evaluation of natural radioactivity in phosphogypsum in industrial areas from Romania

Cited by 21 publications

References 13 publications

Facile preparation of high-strength α-CaSO4·0.5H2O regulated by maleic acid from phosphogypsum: experimental and molecular dynamics simulation studies

Facile preparation of high-strength α-CaSO4·0.5H2O regulated by maleic acid from phosphogypsum: experimental and molecular dynamics simulation studies

Distribution of Natural Radionuclides, Rare Earth Elements, Metals and Metalloids in a Phosphogypsum Stockpile

(Polyphenyl Sulfone - Polyether Sulfone) Blending to Performance Flat Sheet Membrane to Remove Some Heavy and Radioactive Elements from Phosphogypsum Waste

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