Uranium Concentration Research Articles

Highly acid-stable polyvinyl alcohol/chitosan/phytic acid aerogel for selective separation of uranium from actual wastewater

Conventional adsorption materials encounter difficulties in achieving optimal selectivity in uranium-containing wastewater (UCW) because of the low uranium concentration and the presence of diverse coexisting ions. Aerogel, renowned for its abundance of adsorption sites and remarkable structural flexibility, is widely regarded as an innovative material. Nonetheless, its stability in solution hinders its utility in the separation of uranium during wastewater treatment. To counter this limitation, a polyvinyl alcohol/chitosan/phytic acid aerogel (PCPA) was synthesized by employing several polymerization agents. An exceptional degree of selectivity, speed, and stability was achieved in the separation of low concentration uranium from UCW. The results indicated that polyvinyl alcohol (PVA) proved to be the most effective in generating stable aerogels, even when immersed in 0.1 M HCl or acidic UCW. PCPA displayed the highest efficacy in isolating U(VI) in UCW at a pH of 6.0. The novel aerogel exhibited remarkable resistance to ion interference during adsorption, leading to an impressive 96.3 % efficiency in the separation of U(VI) from actual low-concentration UCW. Even after five desorption, PCAC could still achieve U(VI) separation efficiencies of more than 80 %. The adsorption of U(VI) in this aerogel is characterized by chemisorption. PVA plays a crucial role in the condensation process of the aerogel, resulting in an increase in the presence of easily dissociable -OH groups. This, in turn, effectively improves the selectivity of the aerogel. PCPA has demonstrated successful capability in the efficient recovery of uranium from UCW.

Radiation protection for Gabes phosphate area residents: Assessing natural radioactivity in soil and potable water samples

Phosphate mining activities are recognized to be one of various industrial processes generating enhanced Naturally Occurring Radioactive Materials (NORM) by introducing natural radionuclides into the surrounding soils and water bodies, posing a risk to human health.This study was carried out to assess the level of natural radionuclides in soils and potable waters collected from the phosphate area of Gabes city, located in southeastern Tunisia, and to evaluate radiation protection measures by estimating radiological health hazard parameters. Gamma spectrometry system employing an HPGe detector was used in this study to assess 40K, 232Th and 226Ra activity concentration in soils. The average values were found to be 163.7, 14.5, and 7.7 Bq kg−1, respectively, which were lower than worldwide average values. The radiological hazard parameters assessed in this study were radium equivalent activity (Ra-eq), external hazard index (Hex), external gamma absorbed rate (GDR), external annual effective dose (Deff) and excess lifetime cancer risk (ELCR). The calculated average values of the above-mentioned parameters were of 41 Bq kg−1, 0.1, 20.2 nGy h−1, 24.8 μSv y−1 and 8.7 × 10−5 all of which were found to be below their permissible standards.For potable water samples, the activity concentrations of radium were analyzed using an HPGe detector and those of uranium were determined by alpha spectrometry. The average activity concentrations of uranium and radium isotopes in underground water samples were found to be higher than those obtained in tap water samples. For both types of water, the average values for all radionuclides were found to be below their respective reference limits.The annual ingestion effective doses were also estimated in this study. The estimated average values for infant and children for underground water samples were higher than the permissible limit of 100 μSv y−1 set by WHO. The 226Ra was the main contributor to the effective doses for different age categories, followed by 228Ra.

Enhanced capture of uranyl in simulated seawater by supramolecular PSA@PAO hydrogel through carboxyl synergistic effect

Efficient capture of uranium from seawater is of great significance for promoting the sustainable development of nuclear energy and environmental protection. The preparation of highly efficient adsorbent materials plays a key role in this process. In this study, a composite gel PSA@PAO with ultra-high uranium adsorption capacity and excellent desorption efficiency was successfully designed through the supramolecular crosslinking and synergistic effect of glutaraldehyde, hydrazine oxime, sodium alginate, and polyvinyl alcohol. The gel achieved a uranium adsorption capacity of 348 mg·g−1 in a solution with an extremely low uranium concentration (8 ppm) and exhibited ultra-high adsorption selectivity for uranium oxyanions in simulated seawater containing various metal ions. XPS analysis showed that the acylhydrazone groups and carboxylic acid ligands in the PSA@PAO gel could form more stable synergistic uranium complexes. In the desorption solution, the recovery rate of uranium by the PSA@PAO gel reached 98 %, providing a certain strategy for designing efficient adsorbent materials with multi-functional group synergistic effect.

Iron-carbon composite as flow electrode active material for highly efficient electrosorption of uranium from radioactive wastewater

A kind of iron-carbon composite for efficient electrosorption of uranium from radioactive wastewater was prepared by simply carbonization of cellulose and ferric nitrate, and the uranium electrosorption performance and behavior of the iron-carbon composite as flow electrode active material were investigated for low-concentration (below 50 mg/L) uranium-containing wastewater. By regulating the experimental conditions such as cellulose particle sizes, the mass ratio of cellulose/Fe(NO3)3, liquid flow rate, pH, and electric field strength, it was found that under the optimized conditions, the uranium removal ratios were 66.8, 81.92, 95.2, and 97.75 % for initial concentrations of 0.1, 0.5, 5.0, and 50.0 mg/L, respectively. The uranium concentration could be reduced from 0.1 mg/L to 0.0332 mg/L (the emission standard is 0.05 mg/L in China, GB 8798–1996) within 180 min of treatment. In addition, the material maintained an average salt removal rate of 26.27 μg cm−2 min−1 after 36 cycles of electrosorption. It achieved a uranium removal ratio of 87 %, and the upper limit of the electrosorption capacity was still not reached. Combined with X-ray photoelectron spectroscopy (XPS) analysis, the results indicated that the uranyl ion (UO22+) was firstly adsorbed on the surface of the active material after entering the flow electrode. Then, parts of the UO22+(Ⅵ) were reduced to uranium dioxide [UO2(Ⅳ)] under the synergistic action of zero-valent iron (ZVI) and cathodic electro-reduction and were finally immobilized on the electrode surface. This study proposed an innovative application of iron-carbon composite as flow electrode active material in FCDI for the treatment of uranium-containing wastewater with low-concentration (below 50 mg/L).

The Geometric Correction Method for zircon (U–Th) ∕ He chronology: correcting systematic error and assigning uncertainties to alpha-ejection corrections and eU concentrations

Abstract. The conventional zircon (U–Th) / He (ZHe) method typically uses microscopy measurements of the dated grain together with the assumption that the zircon can be appropriately modeled as a geometrically perfect tetragonal or ellipsoidal prism in the calculation of volume (V), alpha-ejection correction (FT), equivalent spherical radius (RFT), effective uranium concentration (eU), and corrected (U–Th) / He date. Here, we develop a set of corrections for systematic error and determine uncertainties to be used in the calculation of the above parameters for zircon, using the same methodology as Zeigler et al. (2023) for apatite. Our approach involved acquiring both “2D” microscopy measurements and high-resolution “3D” nano-computed tomography (CT) data for a suite of 223 zircon grains from nine samples showcasing a wide range of morphology, size, age, and lithological source, calculating the V, FT, and RFT values for the 2D and 3D measurements and comparing the 2D vs. 3D results. We find that the values derived from the 2D microscopy data overestimate the true 3D V, FT, and RFT values for zircon, with one exception (V of ellipsoidal grains). Correction factors for this misestimation determined by regressing the 3D vs. 2D data range from 0.81–1.04 for V, 0.97–1.0 for FT, and 0.92–0.98 for RFT, depending on zircon geometry. Uncertainties (1σ) derived from the scatter of data around the regression line are 13 %–21 % for V, 5 %–1 % for FT, and 8 % for RFT, again depending on zircon morphologies. Like for apatite, the main control on the magnitude of the corrections and uncertainties is grain geometry, with grain size being a secondary control on FT uncertainty. Propagating these uncertainties into a real dataset (N=28 ZHe analyses) generates 1σ uncertainties of 12 %–21 % in eU and 3 %–7 % in the corrected ZHe date when both analytical and geometric uncertainties are included. Accounting for the geometric corrections and uncertainties is important for appropriately reporting, plotting, and interpreting ZHe data. For both zircon and apatite, the Geometric Correction Method is a practical and straightforward approach for calculating more accurate (U–Th) / He data and for including geometric uncertainty in eU and date uncertainties.

Uranium content in drinking water limescale and children’s hair in the Republic of Bashkortostan, Russia

ABSTRACT Analysis of limescales, collected from the walls of kitchenware used to boil drinking water, were used as a surrogate for analysis of uranium in drinking water. Geological features of the territory mainly explained the spatial distribution of uranium concentrations in the samples. Furthermore, uranium was analysed in human hair samples from inhabitants of the region. The median concentration of U in drinking water limescale was 5.4 μg/g (range 0.01 to 61.0 μg/g), and in children’s hair was 0.035 μg/g (range 0.001–0.179 μg/g). A significant correlation (R2 = 0.946) was detected between U in drinking water limescale and U concentration in human hair. Concentrations of uranium in limescales and human hair indicated that the current levels of exposure are in the range of values reported worldwide and are not particularly elevated.

A study of the concentration of uranium in soil samples was evaluated using the CR_39 detector in the south of Amara Governorate

The quantity of uranium in soil samples taken from various residential, industrial, and agricultural areas in southern Iraq's Southern Omara governorate was evaluated using the neutron activation technique for solid-state nuclear track detectors CR-39. Uranium values in soil samples varied from 0.77 ppm to 1.94 ppm, according to the findings. Soil samples were collected at a depth of 10 cm. The outcomes were compared to publicly available data and found to be within acceptable ranges.

Predictive Geogenic Radon Potential (P-GRP): A novel approach for comprehensive hazard assessment and risk modeling in subsurface environment

Geogenic radon potential (GRP) is traditionally used for mapping radon-prone areas. However, this has challenges in the accurate assessment of radon risk because of limitations such as oversimplified soil measurements and lack of geological profiles. This study presents predictive geogenic radon potential (P-GRP), integrating geological characterization and advanced modeling for the emanation and transport of radon in the subsurface environment. Seoul, South Korea, was selected as the research area for the evaluation of hazards using P-GRP, while subway station A was selected for the assessment of indoor health risks. The geology was characterized by the layers of bedrock and soil using uranium contents and porosity. The emanation of radon was modeled considering the radioactive decay chain of uranium and the pore structures. The vertical transport of radon was modeled considering the porosity variation within geological media, which was used for the calculation of P-GRP. Without loss of continuity, the P-GRP map was constructed by calculating P-GRP at a specific depth over the Seoul area. The calculation of P-GRP in the case of subway station A demonstrates that the radon concentration in the bedrock at the platform depth was expected to be 382 million Bqm−3. The indoor radon risk was calculated using the P-GRP by coupling the vapor intrusion process. This presented a high cancer risk for the employees as well as commuters. The P-GRP map of Seoul demonstrated higher hazards in granite zones compared to banded gneiss zones. These results have demonstrated that the P-GRP could be a novel and promising approach for assessing hazard and risk by geogenic radon during subsurface development.

Health risk assessment due to uranium contamination in groundwater: MATLAB based Monte-Carlo simulations

ABSTRACT Uranium contamination is a growing concern due to its inherent toxicity, which poses a significant threat to human health. The health risk assessment due to uranium contamination in groundwater of Mansa district, Punjab (India) is investigated. The LED LF-2a Fluorimeter model by Quantalase (Indore) was used for measurement of uranium concentration in groundwater collected in October 2021 from twenty-six locations. A comparison is conducted between the deterministic and probabilistic approaches since the deterministic approach might either underestimate or exaggerate the risk estimation. Monte-Carlo simulations are used to curtail the associated uncertainties in the data. The simulations are carried out in MATLAB for risk assessment and sensitivity analysis. The deterministic and probabilistic approaches are used to calculate hazard quotient, excess cancer risk and annual effective dose. Using probabilistic approach, the hazard quotient for male and female at 5th percentile is 4.36 and 3.81, respectively. Similarly, the hazard quotient for male and female at 95th percentile is 38.95 and 34.26, respectively. The mean hazard quotient is 18.45 and 15.68 for male and female, respectively, using deterministic approach. The hazard quotient is greater than 1 for both genders (male and female) and excess cancer risk is also higher than 10−4 using both deterministic and probabilistic approaches. The annual effective dose using deterministic approach is 0.23 mSv year−1 whereas using probabilistic approach, the 5th and 95th percentile is 0.56 mSv year−1 and 4.33 mSv year−1, respectively. The sensitivity analysis indicated that the overall risk is more sensitive to concentration of uranium in groundwater and the exposure frequency. This study emphasises on the hazards posed to humans by the ingestion of uranium contaminated groundwater, hence stressing the urgency for taking actions to protect the population of the study area.

Main characteristics and effectiveness analysis of potential helium source rocks in crust-source helium-rich natural gas reservoirs

The evaluation of potential helium source rocks’ effectiveness is a core issue in the field of helium resource exploration and development. However, previous studies predominantly rely on uranium (U) and thorium (T) contents and the age of the rock for evaluating the effectiveness of potential helium source rocks, which fails to fully characterize the key factors affecting their effectiveness. Therefore, this paper takes four typical potential helium source rocks—granite, mud shale, gneisses, and bauxite, as the research object. Through the establishment of a calculation model for accumulated dissolved helium in pore water, combined with gas reservoir examples, a quantitative analysis of dissolved helium accumulation and exsolution in the pores of each potential helium source rock is carried out. This analysis aims to discuss and summarize the effectiveness of each potential helium source rock and the evaluation method for identifying effective helium source rocks. It is believed that: (1) The exsolution of dissolved helium accumulated in the pores of potential helium source rocks into free helium on a large scale under suitable conditions is the key prerequisite for identifying their effectiveness; (2) In addition to the content of U and Th elements, parameters such as large volume, suitable porosity, and water saturation, the good matching relationship of “sedimentary and burial history, gas accumulation history and tectonic evolution history”, and relatively specific helium generation ability are also the key parameters for judging the effectiveness of potential helium source rocks; (3) By establishing the calculation method of dissolved helium enrichment efficiency (ηHe), it is concluded that under similar conditions, free helium enrichment is most easily achieved in granite, followed by mud shale and bauxite, while gneiss poses the greatest difficulty.

Enhanced microbial remediation of uranium tailings through red soil utilization

Seepage of uranium tailings has become a focus of attention in the uranium mining and metallurgy industry, and in-situ microbial remediation is considered an effective way to treat uranium pollution. However, this method has the drawbacks of easy biomass loss and unstable remediation effect. To overcome these issues, spare red soil around the uranium mine was used to enhance the efficiency and stability of bioremediation. Furthermore, the bioremediation mechanism was revealed by employing XRD, FTIR, XPS, and 16S rRNA. The results showed that red soil, as a barrier material, had the adsorption potential of 8.21–148.00 mg U/kg soil, but the adsorption is accompanied by the release of certain acidic and oxidative substances. During the dynamic microbial remediation, red soil was used as a cover material to neutralize acidity, provide a higher reduction potential (<-200 mV), and increase the retention rate of microbial agent (19.06 mL/d) compared to the remediation group without red soil. In the presence of red soil, the anaerobic system could maintain the uranium concentration in the solution below 0.3 mg/L for more than 70 days. Moreover, the generation of new clay minerals driven by microorganisms was more conducive to the stability of uranium tailings. Through alcohol and amino acid metabolism of microorganisms, a reducing environment with reduced valence states of multiple elements (such as S2−, Fe2+, and U4+) was formed. At the same time, the relative abundance of functional microbial communities in uranium tailings improved in presence of red soil and Desulfovirobo, Desulfocapsa, Desulfosporosinus, and other active microbial communities reconstructed the anaerobic environment. The study provides a new two-in-one solution for treatment of uranium tailings and resource utilization of red soil through in-situ microbial remediation.

Evaluation of natural radioactivity and radiological hazards in water sample of Tounsa Sharif, South Punjab, Pakistan

Radioactive material, especially Uranium, is very dangerous for human beings, creatures, and plants. It has been documented that the groundwater of the Dera Ghazi Khan Division in Punjab is contaminated with 238U. In this communication, the groundwater of the Tehsil Taunsa located at Indus River has been investigated. 144 samples of drinking water were collected from 48 villages/towns located in the area of about 500 km2 of the city. The samples were collected in the month of June, August and November, to concentrate on the temperature impact over the Uranium concentration. All samples were analyzed for 238U concentration using a fluorometric technique. The fluorometric technique was applied after pre-treatment of the sample. The analysis of the result revealed that groundwater obtained from this region contains a high value of 238U contents. Among the 48 trials, 26 samples were found below the permissible limit, while the remaining samples contained 238U contents above the permissible level. The sample collected from areas like, Qarim Wala, Jhoke Jamki, Basti peer, Tibi Qaisrani, Pehar Adda & Malana contained even up to the alarming level (30 μg l−1 to 54 μg l−1). In addition, it was observed that the sampling period had a significant effect on the contents, which were most prominent in June. This area being almost annually flooded by water from Rodh Kohi, who originated from Koh-e-Suleiman, may lead to such a high concentration of 238U. The additional reason could be the topographical and geological structure of the earth from which the samples were collected.

Chemical modification of Aspergillus flavus extracted chitosan for uranium remediation from aqueous solution

ABSTRACT Fungal chitosan derived from Aspergillus flavus AFC was employed in the synthesis of a cross-linked polystyrene biopolymer, P-AFC, which was investigated as a biosorbent material for the effective removal of uranium ions U(VI) from aqueous solutions. The characterisation of both fungal biopolymers was achieved using Brunauer-Emmett-Teller (BET) analysis, scanning electron microscopy (SEM), and Fourier-transform infrared (FTIR) spectroscopy. The efficacy of the P-AFC biosorbent in removing uranium from an aqueous solution reached equilibrium in 240 minutes at an initial uranium concentration of 50 ppm, a biosorbent amount of 0.4 g/L, and a pH of 4.0. The maximum biosorption capacity for U(VI) was determined to be 128.21 mg g−1 at room temperature, calculated using the Langmuir model. Furthermore, kinetic and thermodynamic analyses indicated that the biosorption process was characterised by chemisorption, was exothermic, and occurred spontaneously (ΔHo = –59.98 kJ mol−1 and ΔSo = –113.32 J K−1 mol−1). Recycling experiments demonstrated that the material could be reused up to five times without a noticeable decrease in removal efficiency.

Geological characteristics of early cretaceous volcanic rocks and analysis of metallogenic potential of uranium mineralization in Moganshan basin, northern Zhejiang province, China

The Moganshan Volcanic Basin is located in the northeastern section of the Ganhang volcanic-tectonic-uranium polymetallic metallogenic belt. To explore the uranium mineralization potential of these volcanic rocks, petrographic, elemental geochemical, zircon U-Pb chronology, and Sr-Nd-Pb isotope analyses were performed on the volcanic rocks in the Moganshan Basin. The results showed that the volcanic rocks within the Moganshan Basin were formed at 130.8 ± 2.0 Ma; In addition, they are Si-rich (SiO2 content of 72.98%–77.32%), alkali-rich (Na2O+ K2O, with ALK values of =7.15–9.74), and potassium-rich (K2O/Na2O content of 1.41–4.34), with light rare earth elements (Rb, Th Nd, Zr, and Hf). Further more, the volcanic rocks within the Moganshan Basin are deficient in Ba, Ta, Nb, and Sr, with a negative europium anomaly (δEu of 0.10–0.17), high ISr (0.71028–0.71160), low εNd(t) values (−6.43–5.77), and other characteristics. The geological characteristics of the volcanic rocks in the Moganshan Basin are the same as those of the volcanic rocks in eastern China, and the formation age is Early Cretaceous. The formation environment is intra-land extensional and tensional. The rock-forming material primarily originates from the upper crust and has a higher average uranium content than that in the Ganhang volcanic belt. Additionally, it is speculated that the Moganshan Volcanic Basin has good potential for uranium mineralization.

Design and performance of an epithermal neutron detector based on PFN

In this paper, an epithermal neutron detector suitable for the Prompt Fission Neutron (PFN) uranium logging method is designed by Monte Carlo simulation. According to the simulation results, the epithermal neutron detector composed of a 1 mm cadmium (Cd) layer, a 5 mm high-density polyethylene (HDPE) layer, and a 3He tube is sensitive to epithermal neutrons. Through the simulation test of Monte Carlo in formations with different uranium content, the results show that the uranium content in the formation has an obvious linear relationship with E/T, and the detection limit can meet the minimum standard for uranium ore detection. It meets the design expectation and provides a basis for the optimal design of an epithermal neutron detector.

Response of early diagenesis to methane leakage in the inner shelf of the East China Sea

Shelf seas are experiencing a rise in shallow gas leaks, primarily methane, raising concerns due to their environmental impact. However, the effect of the leaks on early diagenesis remains poorly understood. This study analyzes sediment lithology, organic geochemistry and porewater geochemistry of two short cores collected nearby the pockmarks in the muddy inner shelf of the East China Sea. Our findings clearly demonstrate the impact of methane leakage on early diagenesis, evidenced by the shallower position of the SMTZ (sulfate-methane transition zone), higher concentrations of uranium (U), vanadium (V), and manganese (Mn) in the porewater near and above the SMTZ, and downcore decrease in Mg2+, Ca2+, and Sr2+ concentrations versus increase in Mg2+/Ca2+ and Sr2+/Ca2+ ratios. Their profile variations and the difference between two cores are determined by the intensity of methane leakage. The estimated methane diffusive flux of 619 mmol m-2 yr-1 at YEC7–2 is roughly 8.5 times that at YEC7–1 (73 mmol m-2 yr-1), consistent with a shorter distance of YEC7–2 to the pockmark with active methane leakage. A schematic model is summarized to demonstrate the response of early diagenesis processes to the increasing methane leakages in response to changing sedimentation regimes from accretion to severe erosion. This study undoubtedly improves our understanding mutual promotion effect between seafloor erosion and gas leakage, and their impact on early diagenesis processes and resultant porewater geochemical changes and authigenic mineral records.

System optimization study of hybrid K-edge/XRF densitometer for uranium–plutonium solution measurement

In this paper, a comprehensive hybrid K-edge/XRF densitometer (HKED) device model is constructed using MCNP simulation. After the modeling process, a systematic simulation study is conducted to analyze the physical parameters and material selection of KED and XRF. The simulation results reveal that the optimal parameters for the X-ray tube are an X-ray source voltage of 160 kV and a 1 mm Fe filter. The sample should be placed in a vial with an inner diameter of 1.4 cm and an outer diameter of 2 cm. For the KED technique, the determined main parameters are a 1.9 cm Fe filter rod and an inner diameter of 0.08 cm for the collimator. For the XRF technique, the determined main parameters are a 0.01 cm Gd filter and an inner diameter of 0.3 cm for the collimator, with a detector angle of 150°. After selecting appropriate parameters, the average calibration factor Δμ of the KED technique was found to be 3.301 cm2 g−1, with a relative standard deviation (RSD) of 3.36%. Additionally, the comparison between the simulated and calculated values of uranium concentration revealed a minimum measurement error of 0.4%. The minimum detection concentration of KED for uranium solutions is approximately 1 g/L. For plutonium solutions ranging from 0.5 to 20 g/L, linear fitting of the Ka1 net peak area and plutonium concentration showed a coefficient of determination (R2) of 0.999. The detection limit of XRF for plutonium measurement was 2.33✕10−4 g/L. The linear fitting coefficients (R2) of uranium concentration versus K-edge transmission rate and plutonium concentration versus Ka1 net peak area for the hybrid technique in measuring uranium-plutonium mixed solutions are determined as 0.999 and 0.996, respectively, demonstrating the response relationship of the HKED device to uranium and plutonium under different concentrations.

Uranium concentration in groundwater of Charkhi Dadri district of Haryana, India by using LED fluorimeter

Uranium concentration in groundwater of Charkhi Dadri district of Haryana, India by using LED fluorimeter

Hydrodynamic simulation-informed compartment modelling of an annular centrifugal contactor

Abstract The geometrical and hydraulic parameters have a great impact on the mass transfer characteristics of annular centrifugal contactors. The objective of this study is to evaluate the mass transfer performance of a single annular centrifugal contactor by applying the computational fluid dynamics informed compartment modelling approach. In the study, a steady state compartment model of an annular centrifugal contactor is developed in gProms general purpose process modeller by using the hydrodynamic parameters obtained from computational fluid dynamics simulations performed in OpenFOAM with the GEneralised Multifluid Modelling Approach (GEMMA). The mass transfer rate predicted by the developed compartment model is compared with data obtained from uranium extraction with Tributyl Phosphate experiments performed with a laboratory-scale annular centrifugal contactor. Uranium concentrations in the organic and aqueous outlets and the mass transfer rate evaluated by the developed compartmented contactor model are in good agreement with the experimental data. The results reveal that the use of a hydrodynamic-informed compartment modelling approach raises the possibility of designing full-scale annular centrifugal contactors without the need for detailed computational fluid dynamics simulations and the prediction of mass transfer performance of the whole system from laboratory scale experiments.

Reducing operational risks during suspensions separation in rare metals technology

The work presents the results of studies of the solid-liquid separation processes of different mineralogical and granulometric compositions, different viscosity and concentrations of uranium, zirconium, nitric acid, soda, sodium nitrate. It has been shown that the process of industrial filtration is impossible for finely dispersed phases due to the low separation rate. Requirements for the purity of technological solutions of uranium and zirconium for the extraction process are limited by the technological ability of the filter fabric to retain the smallest particles, including chemical compounds with a particle size of 1–5 μm. The control filtration process is only possible under pressure, for which a new disk press filter was created, which reduced the concentration of the solid phase in the filtrate to 0.06 g/L. For difficult-to-filter suspensions, a screw centrifuge was developed, which ensured minimum sediment moisture after separating the finely dispersed phase from a solution of soda and sodium silicate and created conditions for maximum extraction of zirconium and hafnium from the solid phase. The separation of water-soluble sodium silicate ensured the stability of the process of extraction separation of zirconium and hafnium and made it possible to isolate silicon oxide.