Monazite Sand Research Articles

Solvent Extraction and Spectrophotometric Determination of Uranium (VI) Using 2,2′-[1,2-phenylenebis(nitrilomethylidene)]bisphenol (BSOPD) as an Analytical Reagent

2,2'-[1,2-phenylenebis(nitrilomethylidene)]bisphenol (BSOPD) is synthesized in the laboratoryand characterized by NMR, IR and elemental analysis for its purity. This reagent forms a yellowcomplex with U(VI) which can be quantitatively extracted into chloroform at pH 10. This complex inchloroform shows an intense absorption peak at 413.0 nm. It is observed that Beer’s law is obeyed inthe range of 2.0-10.0 ppm of metal solution. It gives a linear and reproducible graph under appropriateconditions, the complex having a molar absorptivity of 3.69 x 104 L mol-1·cm-1. Sandell’s sensitivitycalculated was found to be 4.4 x 10-3μg·cm-2. Nature of the extracted complex, determined by Job’scontinuous variation method, Slope ratio method and Mole ratio method shows that the compositionof U(VI) : BSOPD complex is 1:4. Interference by various ions is studied and masking agents usedwhere required. The proposed method has been applied for the determination of U(VI) in monazite sand and synthetic samples. The results of the analysis are found to be comparable with those obtained by standard method.

Preconcentration procedure using vortex-assisted liquid–liquid microextraction for the fast determination of trace levels of thorium in water samples

A new simple and rapid vortex-assisted liquid–liquid microextraction method was applied for the determination of thorium in water samples. In this method, chloroform used as extraction solvent was directly injected into the water sample solution. The extraction solvent was dispersed into the aqueous phase under vigorously shaking with the vortex. After centrifuging, the fine droplets of extractant phase were settled to the bottom of the conical-bottom centrifuge tube. The effect of different experimental parameters on the performance of the method were studied and discussed. Under the optimum conditions, the detection limit for Th(IV) was 7.5 ng mL−1. The precision of the method, evaluated as the relative standard deviation obtained by analyzing of 10 replicates, was 2.8 %. The practical applicability of the developed method was examined using natural water and monazite sand samples.

TRACE ELEMENTAL ANALYSIS OF SOUTH INDIAN NATURAL EAST COASTAL BEACH SAND DEPOSITS BY PROTON INDUCED X-RAY EMISSION

A selected number of South Indian East Coastal natural beach sand samples were studied with the nuclear analytical and non-destructive Proton Induced X-ray Emission (PIXE) technique. Twenty three elements, including Sc, Zr, Ga, Br, Mo, Nb, Ce, La, and Dy, were identified in these beach sands and may be useful in interpreting the various geochemical conditions and the probable cause of their inceptions in the beach sand matrix. The PIXE technique is a powerful method for quickly determining the elemental concentration of a substance. A 3 MeV proton beam was employed to excite the beach sand samples. The chemical constituents of Ilmenite, Monazite, and Sillimanite beach sands from different parts of the Andhra Pradesh, India were analyzed. In the present article, the usefulness and versatility of the PIXE technique for research in geo-scientific methodology was established.

Solvent Extraction and Spectrophotometric Determination of Uranium (VI) Using 2,2′-[1,2-phenylenebis(nitrilomethylidene)]bisphenol (BSOPD) as an Analytical Reagent

2,2'-[1,2-phenylenebis(nitrilomethylidene)]bisphenol (BSOPD) is synthesized in the laboratoryand characterized by NMR, IR and elemental analysis for its purity. This reagent forms a yellowcomplex with U(VI) which can be quantitatively extracted into chloroform at pH 10. This complex inchloroform shows an intense absorption peak at 413.0 nm. It is observed that Beer’s law is obeyed inthe range of 2.0-10.0 ppm of metal solution. It gives a linear and reproducible graph under appropriateconditions, the complex having a molar absorptivity of 3.69 x 104 L mol-1·cm-1. Sandell’s sensitivitycalculated was found to be 4.4 x 10-3μg·cm-2. Nature of the extracted complex, determined by Job’scontinuous variation method, Slope ratio method and Mole ratio method shows that the compositionof U(VI) : BSOPD complex is 1:4. Interference by various ions is studied and masking agents usedwhere required. The proposed method has been applied for the determination of U(VI) in monazite sand and synthetic samples. The results of the analysis are found to be comparable with those obtained by standard method.

Rare Earth Mining and Exploration in North America

The occurrences of rare earth elements (REEs) in North America are abundant and diverse in mineralogy and geology. The Mountain Pass carbonatite in California historically has been a major world source for the light REEs. Monazite sands have also been mined on a moderate level in the southeastern United States. Fluids released from the mining of uraninite at Elliot Lake, Ontario, were intermittently a source for yttrium. Peralkaline igneous rocks in several areas of North America are currently under exploration for the entire REE spectrum, with emphasis on the heavy REEs. Although many REE occurrences contain a substantial tonnage of REEs, amenability to mineral processing and extraction of the REEs must be definitively established in each case.

Potential Treatment of Inflammatory and Proliferative Diseases by Ultra-Low Doses of Ionizing Radiations

Ultra-low doses and dose- rates of ionizing radiation are effective in preventing disease which suggests that they also may be effective in treating disease. Limited experimental and anecdotal evidence indicates that low radiation doses from radon in mines and spas, thorium-bearing monazite sands and enhanced radioactive uranium ore obtained from a natural geological reactor may be useful in treating many inflammatory conditions and proliferative disorders, including cancer. Optimal therapeutic applications were identified via a literature survey as dose-rates ranging from 7 to 11μGy/hr or 28 to 44 times world average background rates. Rocks from an abandoned uranium mine in Utah were considered for therapeutic application and were examined by γ-ray and laser-induced breakdown fluorescence spectroscopy. The rocks showed the presence of transuranics and fission products with a γ-ray energy profile similar to aged spent uranium nuclear fuel (93% dose due to β particles and 7% due to γ rays). Mud packs of pulverized uranium ore rock dust in sealed plastic bags delivering bag surface β,γ dose-rates of 10-450 μGy/h were used with apparent success to treat several inflammatory and proliferative conditions in humans.

Levels of thoron and progeny in high background radiation area of southeastern coast of Odisha, India

Exposure to radon, (222)Rn, is assumed to be the most significant source of natural radiation to human beings in most cases. It is thought that radon and its progeny are major factors that cause cancer. The presence of thoron, (220)Rn, was often neglected because it was considered that the quantity of thoron in the environment is less than that of radon. However, recent studies have shown that a high thoron concentration was found in some regions and the exposure to (220)Rn and its progeny can equal or several time exceed that of (220)Rn and its progeny. The results of thoron and its progeny measurements in the houses of high background radiation area (HBRA) of the southeastern coast of Odisha, India presented here. This area is one of the high background radiation areas in India with a large deposit of monazite sand which is the probable source of thoron. Both active and passive methods were employed for the measurement of thoron and its progeny in cement, brick and mud houses in the study area. Thoron concentration was measured using RAD-7 and Raduet. A CR-39 track detector was employed for the measurement of environmental thoron progeny, both in active and passive modes. Thoron and its progeny concentrations were found to be comparatively high in the area. A comparison between the results obtained with various techniques is presented in this paper.

Study of stillbirth and major congenital anomaly among newborns in the high-level natural radiation areas of Kerala, India

Monitoring newborns for adverse outcomes like stillbirth and major congenital anomalies (MCA) is being carried out in government hospitals since 1995 in and around high-level natural radiation areas, a narrow strip of land on the southwest coast of Kerala, India. Natural deposits of monazite sand containing thorium and its daughter products account for elevated levels of natural radiation. Among 141,540 newborns [140,558 deliveries: 139,589 singleton, 957 twins (6.81‰), 11 triplets (0.078‰), and one quadruplet] screened, 615 (4.35‰) were stillbirth and MCA were seen in 1,370 (9.68‰) newborns. Clubfoot (404, 2.85‰) was the most frequent MCA followed by hypospadias (152, 2.10‰ among male newborns), congenital heart disease (168, 1.19‰), cleft lip/palate (149, 1.05‰), Down syndrome (104, 0.73‰), and neural tube defects (72, 0.51‰). Newborns with MCA among stillbirths were about 20-fold higher at 190.24‰ (117/615) compared to 8.89‰ (1,253/140,925) among live births (P < .001). Logistic regression was carried out to compare stillbirth, overall, and specific MCA among newborns from areas with dose levels of ≤1.5, 1.51-3.0, 3.01-6.0 and >6mGy/year after controlling for maternal age at birth, gravida, consanguinity, ethnicity, and gender of the baby. Clubfoot showed higher prevalence of 3.26‰ at dose level of 1.51-3.0mGy/year compared to 2.33‰ at ≤1.5mGy/year (OR = 1.39; 95% CI, 1.12-1.72), without indication of any clear dose-response. Prevalences of stillbirth, overall MCA, and other specific MCA were similar across different dose levels and were relatively lower than that reported elsewhere in India, probably due to better literacy, health awareness, and practices in the study population.

Ingestion dose from 238U, 232Th, 226Ra, 40K and 137Cs in cereals, pulses and drinking water to adult population in a high background radiation area, Odisha, India

A natural high background radiation area is located in Chhatrapur, Odisha in the eastern part of India. The inhabitants of this area are exposed to external radiation levels higher than the global average background values, due to the presence of uranium, thorium and its decay products in the monazite sands bearing placer deposits in its beaches. The concentrations of (232)Th, (238)U, (226)Ra, (40)K and (137)Cs were determined in cereals (rice and wheat), pulses and drinking water consumed by the population residing around this region and the corresponding annual ingestion dose was calculated. The annual ingestion doses from cereals, pulses and drinking water varied in the range of 109.4-936.8, 10.2-307.5 and 0.5-2.8 µSv y(-1), respectively. The estimated total annual average effective dose due to the ingestion of these radionuclides in cereals, pulses and drinking water was 530 µSv y(-1). The ingestion dose from cereals was the highest mainly due to a high consumption rate. The highest contribution of dose was found to be from (226)Ra for cereals and drinking water and (40)K was the major dose contributor from the intake of pulses. The contribution of man-made radionuclide (137)Cs to the total dose was found to be minimum. (226)Ra was found to be the largest contributor to ingestion dose from all sources.

Radioactive toothpaste and reversed helicity

Maurice Goldhaber, who died in May 2011, shortly after his 100th birthday (PHYSICS TODAY, May 2011, page 40, and October 2011, page 65), was not only a great nuclear and particle physicist but also a witty and engaging speaker. Many years ago, when someone asked him if he was yet retired from Brookhaven National Laboratory, he said, “How can I be re-tired; I am not even tired yet.”On the occasion of the 50th anniversary of his mentor James Chadwick’s 1932 discovery of the neutron, Goldhaber gave talks about the early days of nuclear physics. When he spoke at the University of Michigan, someone drew his attention to a radioactive toothpaste, named Doramad, that was produced in Germany from the 1920s to the 1940s. At a later talk I attended at Duke University, he showed a poster advertising Doramad. I told him that the toothpaste had been manufactured as a byproduct by the industrial firm Auergesellschaft near Berlin; my father, an organic chemist, worked there until our emigration from Nazi Germany in 1935. During my entire childhood I brushed my teeth with Doramad!Naturally occurring thorium has a half-life of 14 billion years and emits 4-MeV alpha particles—a very mild activity. It was extracted by my father’s company from monazite sand, imported from India primarily as a source of rare-earth elements. Those rare-earth materials were used by the company’s founder, Austrian scientist Carl Auer von Welsbach, to impregnate the mantles in gas lanterns, so they would shine brightly, and for a number of other products, including tinted sunglasses and dyes. As one of the companies involved in the production of nuclear fuel for potential German weapons, the Auergesellschaft also figured in the report of the Alsos Mission, led by Goldhaber’s colleague Samuel Goudsmit. After the war, the company was taken over by Degussa.The health benefits of Doramad were touted on the toothpaste tube: “Its radioactive radiation increases the defenses of teeth and gums. The cells are loaded with new life energy, the bacteria are hindered in their destroying effect. This explains the excellent prophylaxis and healing process with gingival diseases. It gently polishes the dental enamel so it turns white and shiny. Prevents dental calculus.”11. http://www.orau.org/ptp/collection/quackcures/toothpaste.htm.Maurice Goldhaber never forgot that I grew up using radioactive toothpaste.REFERENCESSection:ChooseTop of pageREFERENCES <<1. http://www.orau.org/ptp/collection/quackcures/toothpaste.htm. Google Scholar© 2012 American Institute of Physics.

Extraction of cerium(IV) using tributyl phosphate impregnated resin from nitric acid medium

Tributyl phosphate (TBP) solvent was used for impregnation into Amberlite XAD-16 nonionic polymeric resin beads using the wet method to prepare solvent impregnated resin (SIR). Undiluted TBP in a ratio to the resin support (volume to mass) of 6.0 at room temperature (RT) in 24 h was impregnated the resin with a mass ratio of 1.944, while the prepared gross sample of SIR at the ratio of solvent to resin of 3.0 was impregnated with a mass ratio of 1.88. Cerium(IV) oxide concentrate, prepared from crude Egyptian monazite sand, containing 37% cerium, 1.6% thorium and about 40% the other trivalent rare earth oxides, was used to prepare cerium(IV) nitrate solution for extraction using the prepared SIR. The impregnated resin was satisfactory for Ce(IV) extraction from nitric acid medium at room temperature. Cerium loading capacity of the impregnated resin reached 95.6% of the calculated theoretical capacity (173 g/kg (Ce/SIR)) under the conditions of 51.57 g/L cerium and 2.48 g/L thorium, 5.0 mol/L free nitric acid, solution to resin ratio of 10.0 and contacting the phases for 5.0 min. The loading capacity reached 98.75% when cerium concentration was increased to 91.43 g/L under the same conditions.

Amberlite XAD-2 impregnated Cyanex272: sorption desorption studies of thorium(IV)

Abstract Amberlite XAD-2 impregnated with Cyanex272 was packed in a column and studied for separation and recovery of Th(IV). The effect of various parameters influencing sorption of Th(IV) viz. acid concentration, aqueous phase flow rates, nature and concentration of eluents and other ions were systematically studied. Under optimized conditions Th(IV) was quantitatively sorbed from 0.001 M HNO3 and recovered using 10 cm3 of 4.0 M HCl at 0.6 cm3 min−1 flow rate. Batch studies using impregnated resin were evaluated for using Langmuir and Freundlich adsorption isotherms. The sorption capacity of the impregnated resin for Th(IV) was 8.48 mmol g−1. The limit of detection for Th(IV) was 0.67 μg dm−3 and a reusability for more than 65 cycles was observed. The method developed was applied for isolation of Th(IV) from monazite sand. It was reproducible with a relative standard deviation (R.S.D.) of 0.8%.

Selective separation of U(VI) from its solutions using amine modified silica gel produced from leached zircon

A solution of sodium silicate produced from the alkali fusion of Egyptian zircon mineral as a waste was used to prepare silica gel in the pH range 6–7. The surface of the obtained silica was functionalized with diethylenetriamine (DET) and tetraethylenepentamine (TEP) to give triamine modified silica (TAMS) and pentamine modified silica (PAMS), respectively. The success of functionalization process was confirmed by means of FT-IR, energy dispersive X-ray analysis (EDX) and elemental analysis. The surface properties of the modified silica obtained were also investigated. The uptake behavior of the modified silica towards U(VI) ions at different experimental conditions of pH, time, concentration and temperature was studied. The maximum uptake values at 25 °C were found to be 90.3 and 112 mg/g for TAMS and PAMS, respectively. Kinetics and thermodynamics studies showed an endothermic pseudo-second order adsorption process. Regeneration of the loaded silica was performed using 1 M HNO 3. The investigated silicas have successfully been applied for extracting of U(VI) obtained from alkaline leaching of Egyptian monazite sand.

Selective separation of Th(IV) from its solutions using amine modified silica gel produced from leached zircon

A solution of sodium silicate produced as a waste from the alkali fusion of Egyptian Rosetta zircon mineral was used for preparation of a silica gel in the pH range 6–7. A silica gel modified with tetraethylenepentamine (TEP) and diethylenetriamine (DET) functionalities were prepared. The success of immobilization process was confirmed by means of FT-IR, energy dispersive X-ray spectrometric analysis (EDX) and elemental analysis. The surface properties of the modified silica obtained were investigated by means of nitrogen surface area. The uptake behaviour of the modified silica towards Th(IV) ions at different experimental conditions of pH, time, concentration and temperature using batch method was studied. Kinetics and thermodynamics studies showed an endothermic pseudo-second order adsorption process. Regeneration of the loaded silica was performed using 1 M HNO3. The investigated silicas have successfully been applied for separating of Th(IV) from U(VI) in nitric acid solution obtained from alkaline leaching of Egyptian monazite sand.

Changes in coastal morphology at Kalpakkam, East Coast, India due to 26 December 2004 Sumatra tsunami

The tsunami which struck the east coast of India on 26 December 2004 caused a significant impact at Kalpakkam coast. To study the effect of the tsunami on the coastal environment, high-resolution satellite images of pre (19 November 2004) and post (29 December 2004) data were used. Aerial images of Kalpakkam coast of 28 December 2004 were employed to demarcate precisely the inundation zones and assess the impact in detail on land-use/land-cover features. The area affected by the tsunami is mapped using satellite images. The prominent changes in vegetation pattern, water-logged areas, soil wetness, creek pattern and sand deposition were delineated with the help of visual analysis. The inundation mapping derived from satellite imagery was validated with the help of ground truth data obtained from the field survey on 28 December 2004. The present study shows that at Kalpakkam coast, inundation ranges between 95 and 530 m, and the run-up varies between 3.3 and 7.7 m. The morphological changes along the coast in the form of reappearance of old drainage have been observed. Coastal vegetation such as small shrubs and grasses was either washed away or uprooted. A fair amount of sediments, including traces of monazite sands, were deposited all along the coast.

Heterogeneity of uranium in water from south peninsular India

The South Peninsular India is known to have very high levels of natural background radiation due to the monazite rich beach sand. Primordial uranium is ubiquitous and the heaviest radio toxic trace element available in all terrestrial substances at varying levels depending on the geology of the region. Uranium series supports several short-lived radioisotopes during its decay including radium. Uranium in drinking water is important in terms of the ingestion dose also. This report depicts the results of uranium analysis of 600 water samples collected from the south coast peninsular region extending parts of Kerala and Tamilnadu states of India through fission track registration technique. Results of the analyses of water samples collected from different sources in the south coast of India show that uranium concentrations vary from 0.82 µg/l to 7.32 µg/l equivalents to the specifi c activity of 10.33 Bq/m 3 and 92.23Bq/m 3 , respectively. Estimated daily intake of uranium through drinking water ranges from 20.22 to 18.58mBq/kg and is lower than the recommended limits of intake. The heterogeneity in distribution of uranium in water bodies is due to the presence of monazite sand deposited in the coast over the years.

LIQUID - LIQUID EXTRACTION OF CERIUM(IV) FROM SALICYLATE MEDIA USING N-7V-OCTYLANILINE IN XYLENE AS AN EXTRACTANT

Extraction behaviour of Ce(IV) from salicylate medium has been studied with the using N-n-octylaniline in xylene as an extractant. Cerium(IV) was completely recovered from the organic phase using 2.0 M hydrochloric acid and determined spectrophotometrically as complex with Arsenazo III. The influence of equilibrium pH, extractant concentration, stripping agents, equilibration time, nature of diluents, and diverse ions on the extraction of Ce(IV) was investigated. The stoichiometry of the extracted species was determined on the basis of slope analysis. The separation of Ce(IV) was carried out from some associated metals like U(VI), Th(IV), La(III), Y(III), Zr(IV), Nb(V), Gd(III) and Nd(III). The method presented is simple, reproducible, rapid and has been successfully applied for the determination of Ce(IV) in synthetic mixture, semiconductor films and monazite sand.

Preliminary indoor thoron measurements in high radiation background area of southeastern coastal Orissa, India

This paper presents the preliminary results of radon and thoron measurements in the houses of Chhatrapur area of southeastern coast of Orissa, India. This area is one of the high radiation background radiation areas in India, which consists of monazite sand as the source of thoron. Both active and passive methods were employed for the measurements. Radon and thoron concentrations were measured in the houses of Chhatrapur area using twin cup radon dosemeters, RAD7 and radon-thoron discriminative detector (Raduet). Thoron progeny concentration was also measured in the houses using deposition rate measurements. Radon and thoron concentrations in the houses of study area were found to vary from 8 to 47 Bq m(-3) and the below detection level to 77 Bq m(-3), respectively. While thoron progeny concentration in these houses ranges between 0.17 and 4.24 Bq m(-3), preliminary investigation shows that the thoron concentration is higher than radon concentration in the houses of the study area. The thoron progeny concentration was found to be comparatively higher, which forms a base for further study in the area. The comparison between the results of various techniques is presented in this paper.

Identification of multiple rare earths and associated elements in raw monazite sands by laser-induced breakdown spectroscopy

Laser-induced breakdown spectroscopy (LIBS) is an emerging and promising tool for rapid and efficient elemental analysis. We used the LIBS technique to analyze the raw monazite sands collected from the beaches in southern Bangladesh. We have detected a number of rare earths (lanthanides) such as cerium, lanthanum, praseodymium, neodymium, yttrium, ytterbium, gadolinium, dysprosium and erbium, in addition to other metallic elements such as zirconium, chromium, titanium, magnesium, manganese, niobium and aluminum. To the best of our knowledge, this is the first time multiple rare earths have been identified in a natural mineral by LIBS.

Sorption study of U(VI), Th(IV) and Ce(III) on poly[dibenzo-18-crown-6] in l-arginine to develop sequential column chromatographic separation method

A simple and efficient column chromatographic method has been developed for the sequential separation of U(VI), Th(IV) and Ce(III) using poly[dibenzo-18-crown-6] as stationary phase and l-arginine as a counter ion. The different elution patterns with various eluting agents were observed for individual element. The capacity of poly[dibenzo-18-crown-6] for U(VI), Th(IV) and for Ce(III) was found to be 0.96, 0.86 and 1.49 (±0.01) mmol/g of crown polymer, respectively. The method is efficient to separate the elements in multicomponent mixtures and has good recovery. The method is extended to determine the U(VI), Th(IV) and Ce(III) from monazite sand. The method is simple, rapid and selective having good reproducibility (~±2%).