A Cascade Impactor for Mineral Particle Analysis

Cunha, K. Dias da; Lipsztein, J. L.; Fang, C. P.; Leite, C. V. Barros

doi:10.1080/02786829808965557

Cited by 12 publications

(4 citation statements)

References 9 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The particle size distributions were determined using a six-stage cascade impactor with an operational flow rate of 12 l/min, and cut-off diameters of 0.64, 1.0, 2.4, 4.7, 9.9 and 19.4 μm (Dias da Cunha et al 1998b). The cascade impactor was located near the workers at the point of highest total dust concentration and at 1.5 m from the soil.…”

Section: Experimental Methodsmentioning

confidence: 99%

Tantalum Dissolution Rate in Simulant Lung Fluid

Lima

Coelho

Dalia

et al. 2007

Water Air Soil Pollut

Self Cite

View full text Add to dashboard Cite

The aim of this study is to determine the solubility rate of tantalum contained in pyrochlore, columbite-tantalite and columbite in simulant lung fluid. The International Commission on Radiological Protection (ICRP), in its recommendation for limiting intakes of radionuclide by workers, has consistently recognized that the biological behavior of any specific material after incorporation can significantly diverge from model prevision. Model parameters should be adjusted to adapt the model for each specific substance material in order to estimate the dose due to this element intake. The most recent ICRP publication 66, respiratory tract dosimetry model, point out that information as data like particle size, aerosols solubility and the material chemical compounds are important parameters in the dose coefficients calculation. This paper studies the solubility in Simulant Lung Fluid (SLF) of Ta present in mineral dust particles. For this study 3 minerals were selected: pyrochlore, columbite-tantalite and columbite. Tantalum dissolution in vitro samples were obtained using the Gamble solution and PIXE (Particle Induced X-ray Emission) as analytical technique. In order to characterize the worker exposure to Ta bearing particles, one Brazilian niobium mine was selected. The mineral dust particles were collected using a sixstage cascade impactor and the elemental mass concentrations and the MMAD (Mass Median Aerodynamic Diameter) were determined. Concentrations of radionuclides from natural series of thorium and uranium were also determined. The results show that the workers are exposed to Ta bearing particles in the respirable fraction of aerosols (aerodynamic diameter (d aer ) <2.5 μm) during the mineral processing to obtain Fe-Nb alloy. The solubility in Simulant Lung Fluid (SLF) of Ta present in mineral dust particles depends on the mineral characteristics. The solubility half-time varies between 34 and 62 h depending on the associated mineral.

show abstract

Section: Experimental Methodsmentioning

confidence: 99%

Tantalum Dissolution Rate in Simulant Lung Fluid

Lima

Coelho

Dalia

et al. 2007

Water Air Soil Pollut

Self Cite

View full text Add to dashboard Cite

show abstract

“…The CI operational flow rate was 12.5 L min −1 and the total volume was measured by a volume integrator system. The cut-off diameters of each stage of the CI are 19.9, 9.9, 4.7, 2.4, 1.0 and 0.64 μm, respectively (Dias da Cunha et al 1998). The airborne particles in the fine fraction of aerosol (d aer <2.5 μm) were collected using the portable air samplers with cyclone at four sampling sites: Punta Plaza, Ipanema refuge, Flagstaff I, and Flagstaff II.…”

Section: Aerosol Samplingmentioning

confidence: 99%

Atmospheric Impacts due to Anthropogenic Activities in Remote Areas: The Case Study of Admiralty Bay/King George Island/Antarctic Peninsula

Leal

Joppert

Licínio

et al. 2007

Water Air Soil Pollut

Self Cite

View full text Add to dashboard Cite

“…Metal-bearing particle inhalation can cause damage for workers health. Previous studies have shown that these workers are exposed to mineral dust particles (Dias da Cunha et al 1998a, b, 2002. At this plant, the workers are exposed to Ta-bearing particles, by inhalation and by ingestion of drink water containing Ta (Dália 2006).…”

Section: Introductionmentioning

confidence: 99%

Dissolution Factors of Ta, Th, and U Oxides Present in Pyrochlore

Cunha

Santos

Zouain

et al. 2009

Water Air Soil Pollut

Self Cite

View full text Add to dashboard Cite

Air pollution can be a problem in industrial processes, but monitoring and controling the aerosols in the work place is not enough to estimate the occupational risk due to dust particle inhalation. The solubility in lung fluid is considered to estimate this risk. The aim of this study is to determine in vitro specific dissolution parameters for thorium (Th), uranium (U), and tantalum (Ta) associated to crystal lattice of a niobium mineral (pyrochlore). Th, U, and Ta dissolution factors in vitro were obtained using the Gamble solution (simulant lung fluid, SLF), particle induced X-ray emission, and alpha spectrometry as analytical techniques. Ta, Th, and U are present in the pyrochlore crystal lattice as oxide; however, they have shown different dissolution parameters. The rapid dissolution fraction (f r ), rapid dissolution rate (λ r ), slow dissolution rate (f s ), and slow dissolution fraction (λ s ) measured for tantalum oxide were equal to 0.1 and 0.45 and 0.00007 day −1 , respectively. For uranium oxide, f r was equal to 0.05, λ r was equal to 1.1 day −1 , and λ s was equal to 0.000068 day −1 . For thorium oxide, f r was 0.025, λ r was 1.5 day −1 , and λ s was 0.000065 day −1 . These results show that chemical behavior of these three compounds in the SLF could not be represented by the same parameter. The ratio of uranium concentration in urine and feces samples from workers exposed to pyrochlore dust particle was determined. These values agree with the theoretical values of estimated uranium concentration using specific parameters for uranium oxide present in pyrochlore.

show abstract

A Cascade Impactor for Mineral Particle Analysis

Cited by 12 publications

References 9 publications

Tantalum Dissolution Rate in Simulant Lung Fluid

Tantalum Dissolution Rate in Simulant Lung Fluid

Atmospheric Impacts due to Anthropogenic Activities in Remote Areas: The Case Study of Admiralty Bay/King George Island/Antarctic Peninsula

Dissolution Factors of Ta, Th, and U Oxides Present in Pyrochlore

Contact Info

Product

Resources

About