Recovery Of Boron Research Articles

A Review on Various Techniques for Boron Recovery: Focusing on Efficiency, Sustainability, Scalability, and Cost-Effectiveness

Boron is a critical element extensively used across various industries—such as glass manufacturing, ceramics, agriculture, detergents, nuclear energy, and aerospace—due to its unique chemical and physical properties. However, its widespread industrial use has raised significant environmental concerns, particularly its accumulation in aquatic systems, posing risks to biodiversity, plant life, and human health. This review examines the impacts of boron pollution on aquatic organisms, plants, and humans, highlighting the necessity for effective recovery strategies. We provide a comprehensive analysis of boron recovery techniques—such as reverse osmosis, electrodialysis, nanofiltration, adsorption, membrane distillation, and leaching—focusing on their efficiency, sustainability, scalability, and cost-effectiveness. The evaluation compares each method’s operational parameters, environmental impact, and economic feasibility. While methods like reverse osmosis and electrodialysis offer high removal efficiencies, they are often limited by operational costs and environmental drawbacks. Alternative methods like adsorption and nanofiltration present more sustainable and cost-effective options but may require optimization for large-scale applications. This review underscores the need for advanced, economically viable, and sustainable boron recovery technologies to mitigate environmental risks and comply with regulatory standards.

Sustainable treatment of boron from oilfield produced water for optimum recovery using zirconium chloride oxo-precipitation

This study focuses on the recovery of boron from oilfield-produced water employing the chemical oxo-precipitation method. Zirconium chloride was used to recover boron as a sustainable approach. The study aimed to optimize the parameters to achieve the highest possible boron recovery. It also sought to investigate the impact of operating parameters, including pH, time, oxidizing agent, and dosage of the precipitant, on boron recovery. The optimal operating conditions were optimized through response surface methodology (RSM). A comparative study was conducted with barium chloride (chemical oxo-precipitation) and calcium hydroxide (conventional precipitation). The results indicated that the highest boron recovery was achieved at 97% by utilizing chemical oxo-precipitation with zirconium chloride. Meanwhile, barium chloride and calcium hydroxide recovered boron at 89% and 88%, respectively. The precipitates were characterized by Fourier transform infrared (FTIR), x-ray fluorescence (XRF), scanning electron microscopy (SEM), and energy dispersive x-ray spectroscopy (EDX). The XRF and EDX characterization analysis confirmed the highest boron recovery at 97% with zirconium chloride. SEM showed that zirconium chloride precipitated visible amorphous insoluble solids. The chemical-oxo-precipitation procedure outperforms barium chloride and calcium hydroxide precipitation. The zirconium chloride oxo-precipitation method was proved to be a greener solution for boron recovery.

Production of boric acid by bipolar membrane electrodialysis: Evaluation of commercial and polyelectrolyte multilayers-coated ion exchange membranes

Boron is an essential element for many industrial sectors, but the European Union (EU) is entirely dependent on imports for its boron supply. To ensure a sustainable supply of boron for the EU, developing recovery strategies from secondary sources is essential. Thus, boron recovery from seawater reverse osmosis (SWRO) desalination brines using bipolar membrane electrodialysis (BMED) as part of a multi-mineral brine mining process is proposed. BMED experiments were conducted with 35 triplets of commercial membranes (100 cm2), using sodium borate solution (92.5 mM) as feed, at three different pHs (2, 9 and 12), identifying pH 12 as the best option. Moreover, commercial ion exchange membranes from PCA GmbH and Mega a.s. were coated with polyelectrolyte multilayers using layer-by-layer technique. Characterization of the coated membranes included zeta potential, contact angle, ATR-FTIR, transport number and ion exchange capacity analyses. Subsequent BMED experiments with three triplets comparing virgin and modified membranes (100 cm2), using sodium borate solution (92.5 mM) as feed, demonstrated that the coating with 4 bilayers increased the selectivity of membranes. Although the coated RALEX membranes presented the highest selectivity (7.2 for B(OH)4-/Na+ in the acid compartment), uncoated PCA membranes were the optimal choice for H3BO3 and NaOH production due to higher Na and B removal (97 %), higher concentration factors (2.5 for the acid and 4.3 for the base), and higher current efficiency for H3BO3 production (78 %).

Recovery of boron and zinc from wastewater via electrodialytic metathesis

With the development of industrial civilization, large amounts of wastewater containing boron and zinc are being produced. Such wastewater poses a great threat to human health if discharged without treatment. In this study, an integrated technology of electrodialytic metathesis (EDM) and a hydrothermal process was utilized to recover boron and zinc from wastewater in the form of zinc borate (Zn2B6O11·3H2O). Experimental results showed that electrolyte concentration, current density, and initial boron and zinc concentration clearly affected the recovery ratios for B4O72− and Zn2+ and their corresponding specific energy consumption and current efficiencies. Under the optimal experimental conditions (an electrolyte concentration of 1.0 mol/L in the recycling compartment in the experimental setup, a current density of 15 mA/cm2, initial ZnSO4 and Na2B4O7 concentrations of 0.1 mol/L, and a flow rate of 20 mL/min), the recovery ratio, specific energy consumption, and current efficiency were 85.6 %, 6.5 kW·h/mol, and 12.3 %, respectively, for recovering B4O72− and 80.6 %, 1.7 kW·h/mol, and 45.7 %, respectively, for recovering Zn2+. When one recovery compartment was employed, the current efficiencies for recovering B4O72− and Zn2+ were 12.3 % and 45.7 %, respectively, and these values were 11.4 % and 43.8 %, respectively, when two recovery compartment were used. After B4O72− and Zn2+ concentrated by EDM were treated via a hydrothermal process, a white precipitate was produced. The results of X-ray diffraction, Fourier transform infrared spectroscopy, and thermogravimetric analyses showed that this precipitate exhibited physicochemical properties similar to those of commercial Zn2B6O11·3H2O. Thus, the integrated technology can be regarded as an effective method for recovering boron and zinc from wastewater.

Accurate Boron Determination in Tourmaline by Inductively Coupled Plasma Mass Spectrometry: An Insight into the Boron-Mannitol Complex-Based Wet Acid Digestion Method.

Tourmaline, a boron-bearing mineral, has been extensively applied as a geothermometer, provenance indicator, and fluid-composition recorder in geological studies. In this paper, the decomposition capability of an HF-HNO3-mannitol mixture for a tourmaline sample was investigated in detail for the first time, and a wet acid digestion method based on the boron-mannitol complex for accurate boron determination in tourmaline by inductively coupled plasma mass spectrometry (ICP-MS) was proposed. With a digestion temperature of 140 °C, tourmaline samples of 25 mg (±0.5 mg) can be completely decomposed by a ternary mixture, which consisted of 0.6 mL of HF, 0.6 mL of HNO3, and 0.7 mL of 2% mannitol (wt.), via a continuous heating treatment of 36 h. Following gentle evaporation at 100 °C, the sample residues were re-dissolved using 2 mL of 40% HNO3 solution (wt.) and diluted to about 2.0 × 105-fold by a two-step method using 2% HNO3 solution (wt.). The boron contents in a batch of parallel tourmaline samples were then determined by ICP-MS, and results showed that the boron concentration levels were in a range of 3.20-3.44% with determination RSDs less than 4.0% (n = 5). It was found that the boron concentrations obtained at the mass of 10B were comparable with results from the measurements at the mass of 11B. This revealed that the usage of 2% mannitol with a quantity as high as 0.7 mL in this developed approach did not exhibit significant effect on the quantification accuracy of boron at the mass of 11B. It was also found that the processes including fluoride-forming prevention and fluoride decomposition deteriorated the boron-reserving efficiency of mannitol for tourmaline, causing the averaged boron contents to vary from 2.25% to 3.57% (n = 5). Furthermore, the stability of the boron-mannitol complex under 185 °C by applying the laboratory high pressure-closed digestion method was evaluated, which showed that there existed a 60.36% loss of boron compared to that under 140 °C by using this proposed approach. For this ternary mixture, the tourmaline decomposing efficiency was found to be weakened prominently using 100 °C as the digestion temperature, and tourmaline powders can be observed even after 72 h of continuous heating with B contents within 1.09-1.23% (n = 5). To assess the accuracy of this developed method, the boron recovery of anhydrous lithium tetraborate was studied. It was found that the boron recoveries were within 96.59-102.12% (RSD < 1%, n = 5), demonstrating the accuracy and reliability of this proposed method, which exhibits advantages of high B preserving efficiency, and giving concentration information of both B and trace elements simultaneously. By applying such a boron-mannitol complex-based wet acid digestion method, the chemical composition of boron and trace elements in three tourmaline samples from different pegmatites were quantified, which provided valuable information to distinguish regional deposits and the associated evolution stages.

Continuous recovery of lithium and boron from Jezechake Salt Lake brine using fixed-bed adsorbers

Jezechake Salt Lake brine in China is rich in lithium ions coexisting with relatively high concentrations of carbonate and borate anions. Both carbonate and borate anions have a pH-buffering ability to accept the exchanged H+ ions of lithium ion sieves, enhancing the adsorption process of Li+ ions. When Jezechake Salt Lake brine passes through a titanium-type ion-sieve-packed column, good lithium breakthrough occurs owing to the pH-buffering action in the brine, which is of great significance for effective lithium recovery from brines in industrial production. In addition, the boron content of Jezechake Salt Lake brine is high, and its recovery is valuable for industrial applications. Here, an N-methylglucamine resin-packed column was connected in series behind a titanium-type ion-sieve-packed column to obtain boron simultaneously with the aim of lowering the energy consumption and cost of lithium recovery. During the adsorption process, Jezechake Salt Lake brine was successively fed into the lithium and boron adsorption columns. The two packed columns were then desorbed independently through acidic solution washing to obtain the Li and B eluents. The breakthrough behavior and elution performance of Li and B in the packed columns were investigated experimentally, and the practicability and efficacy of the proposed process were assessed.

RECOVERY OF BORON WASTES WITH INORGANIC ACID

Approximately 73-74% of boron mineral reserves all over the world are located in the Western Anatolian region of Turkey, in the provinces of Eskişehir, Kütahya, Balıkesir, and Bursa. The most intense minerals extracted from these fields are colemanite, ulexite, and tincal minerals, respectively. The general principle in the recovery of these minerals is to extract the raw ore and obtain it by size reduction processes of concentrates in high grade. In addition to concentrates, boric acid (H3BO3) production is also possible in Balıkesir and Kütahya. The production of this acid in question includes a series of processes from dissolution with sulfuric acid at high temperatures to crystallization. In this study, except for the aforementioned high concentrations, boron recovery from clay waste, which is high in boron content and is collected from plant waste ponds, is investigated. For this purpose, ulexite-colemanite-containing slime wastes of the Bigadiç (Balıkesir) Plant were dissolved in 7% solids at 60°C in different sulfuric acid concentrations (1-6% H2SO4) and were obtained with 83-97% B2O3 recovery. When the boron wastes are evaluated, issues such as the discovery and establishment of a new waste pond/dam will be solved, the valuable content in the wastes will be recovered, and the environmental problems of boron and other contents in clay will be eliminated. This article includes information about the characterization of the structure by considering the dissolution of boron and other compounds, as well as obtaining boric acid from inorganic acid and boron wastes.

Specific Removal and Recovery of Bromide Ions: The Search for Stable Electrodes and Operation Modes

In previous work, we introduced an elegant approach for bromide recovery from water by the introduction of a hybrid physical adsorption and capacitive deionization processes for selective removal and recovery of boron from water. In this paper, we show that the harsh environment of water contaminated with bromine-moieties adversely affects the longevity of relevant electrodes, with close to 100 consecutive work hours of bromides removal without noticeable degradation. To extend the lifespan of electrodes, we used an asymmetric CDI cell with a 1:5 positive/negative electrodes ratio in which a polarity switch between electrodes is applied every six adsorption-desorption cycles in a way that in each adsorption-desorption cycle, a different electrode of the six electrodes, functions as the positive electrode. We deduce that the polarity switch reduces oxidation and subsequent degradation of the positive electrodes, resulting in an extended lifecycle. After examining nine different carbonaceous materials, carbon cloth was chosen to be incorporated in the bromide- recovery cells because of its favorable kinetics and its physical and mechanical properties. We show that with a combination between endurance of the electrodes and asymmetric mode of operation, it is possible to overcome the main barrier that holds the technology from being practical.

Selective separation and recovery of boron from spent Nd-Fe-B magnets leaching solution

The accumulation of boron during the recovery of rare earth elements (REEs) from spent Neodymium-Iron-Boron (Nd-Fe-B) magnets affects the extraction of REEs and causes environmental pollution through the boron-containing wastewater. Given that boron is a globally scarce strategic resource, this study proposes a method for the selective separation and recovery of boron from spent Nd-Fe-B magnets leaching solution. The synergistic extraction of boron adopting 2-ethylhexanol (EHA) and 2-ethyl-1,3-hexanediol (EHD), and the extraction mechanism were investigated. Under optimized conditions (30 % EHA-20 % EHD-50 % sulfonated kerosene, 1:1O/A phase ratio, pH 3.3, 10 min), the two-stage countercurrent extraction achieved a remarkable 99.9 % extraction efficiency with minimal loss of REEs. Slope analysis, Raman, FT-IR, and NMR combined with DFT were used to elucidate the extraction mechanism. Specifically, some of the boric acid molecules complexed with the OH groups of EHD to form stable six-membered ring complexes, while another part bound with both EHA and EHD to form linear complexes containing six-membered rings. Employing 0.4 mol/L NaOH as the stripping agent, the two-stage countercurrent stripping process achieved a stripping efficiency of 99.8 %. Subsequently, borax pentahydrate products exceeding 99 % purity were obtained via evaporative crystallization from the stripping solution. Notably, the raffinate contained only ∼ 5 mg/L of boron, which could be further reduced below the discharge standard via the REEs recovery process, allowing for safe emission. This work offers a novel approach for the selective separation and recovery of boron from spent Nd-Fe-B magnets, eliminating its adverse effects on REEs extraction and the environment, while simultaneously recovering a valuable resource.

Selective recovery of boron, cobalt, gallium and germanium from seawater solar saltworks brines using N-methylglucamine sorbents: Column operation performance

The European Union (EU) identified a list of Critical Raw Materials (CRMs) crucial for its economy, aiming to find alternative sources. Seawater is a promising option as it contains almost all elements, although most at low concentrations. However, to the present, the CRMs' recovery from seawater is technically and economically unfeasible. Other alternatives to implement sea mining might be preferred, such as reverse osmosis brines or saltworks bitterns (after sodium chloride crystallisation). The CRMs' extraction in a selective way can be achieved using highly selective recovery processes, such as chelating sorbents. This study focuses on extracting Trace Elements (TEs) from solar saltworks brines, including boron, cobalt, gallium and germanium, using commercial N-methylglucamine sorbents (S108, CRB03, CRB05). The application of these sorbents has shown potential for boron recovery, but their selectivity for cobalt, gallium, and germanium requires further investigation. This research aims to assess these sorbents' kinetics and column mode performance for TEs recovery from synthetic bitterns. Boron and germanium were rapidly sorbed, reaching equilibrium (>90 %) within 1 h, except for S108, which took 2 h. In column mode, 20–25 pore volumes of bittern were treated to remove boron and germanium, but competition from other elements reduced treatment capacity. An acidic elution (1 M hydrochloric acid) allowed to elute them (>90 %), reaching concentration factors for germanium and boron of 35 and 11, respectively, while cobalt and gallium had less affinity for the sorbents. In addition, the experiments performed were fitted by a mass transfer model to determine the equilibrium constants and selectivities. Therefore, bittern mining has been proven as a secondary/alternative source to obtain CRMs, which can lead the EU to a position in which its dependence on other countries to obtain these raw materials would be decreased.

Boron Recovery from Organic Solutions Used in Brine Treatment through a Water Stream

This research evaluates the modification of the lithium carbonate (Li2CO3) production process and particularly the boron removal step, which currently employs a recirculated stream. This recirculated stream is a liquor with low boron content but rich in lithium, currently being wasted. In this process, the recirculating stream is substituted with a freshwater stream. Boron is re-extracted from the loaded organic stream to form an input stream for a boric acid process. Under certain operational conditions, the formation of emulsions was observed; due to this, the analysis of emulsion formation involved controlling the pH of each sample, which lead to the development of a procedure to prevent such formations. From this analysis, it was determined that emulsions form in water with pH values below 1.3 and above 6.9. In addition, a speciation analysis showed that the concentrations of the H2BO3− and H+ species influence the formation of emulsions. The mass balance of the process showed that by replacing the recirculated stream, boron recovery of 89% was achieved, without the need to add new stages or equipment.

Liquid-liquid extraction of boron from continental brines by 2-butyl-1-octanol diluted in kerosene.

Lithium production from brines generates significant quantities of salts, including boron, that are not effectively utilized and end up being stored in landfills. This study delves into a novel approach for directly extracting boron from native brines without performing solar evaporation as an alternative to traditional methods based on boron extraction from ores, offering a sustainable route to producing boric acid or borax. By exploring factors such as 2-butyl-1-octanol concentration, phase volume ratio, temperature, and pH, the research scrutinizes boron extraction efficiency from two native brines sourced from the salar de Hombre Muerto in Argentina, alongside a synthetic brine simulating these native compositions. Notably, the extractant demonstrates exceptional promise due to its limited solubility in the brine, measuring at just 18 mg L-1. Optimal conditions-2 mol L-1 2-butyl-1-octanol, O/A ratio of 4, 25 °C temperature, and pH of 5.5-resulted in a remarkable 98.2% and 94.2% recovery of boron from synthetic and native brines, respectively. Importantly, this extraction process showcased minimal co-extraction of lithium, calcium, magnesium, potassium, and sodium. Leveraging these findings, a proposed flowsheet outlines a highly selective method for extracting boron from brines, presenting an alternative avenue to conventional borax production from boron ores.

К ВОПРОСУ ПОЛУЧЕНИЯ ФОРСТЕРИТСОДЕРЖАЩЕГО ЛИТЬЯ ИЗ ХВОСТОВ БОРОИЗВЛЕЧЕНИЯ И СТЕКЛОБОЯ ЭЛЕКТРОДУГОВЫМ СПОСОБОМ

The article investigates the characteristics of man-made waste in form of boron tailings (China) and cullet to establish the possibility of their joint use as a raw material composition in production stone forsteritecontaining casting by electric arc method. It studies of granulometric elemental, chemical and mineralogical composition of raw materials, using dispersion-gravimetric, Ultraviolet-Visible spectroscopic, microscopic, energy dispersion, as well as X-ray phase analyses. The study established true density, specific surface area, granulometric, elemental, chemical and mineralogical (XFA) compositions of raw materials and calculated modulus of acidity of the melt, which amounted to Mk = 2.04. It allows casting from two-component charge (tailings cullet) represented by percentage ratio of 70:30. In process of electric arc melting of the raw material composition, forsterite-containing stone casting was obtained, which is solidified melt of a given geometric shape made of forsterite (Mg2SiO4) in a glass phase. Thus, the conducted complex of studies testifies to the suitability of man-made waste represented by boron recovery tailings and cullet for obtaining a melt from them by electric arc method, with further production of forsterite-containing stone casting.

Sustainable treatment of boron industry wastewater with precipitation-adsorption hybrid process and recovery of boron species

Boron removal from wastewater has been investigated by using various processes, including ion exchange resins, membrane processes and adsorption. Each method has various advantages and disadvantages, but most produce excessive waste in addition to high operational costs. Therefore, more sustainable methods are required for wastewater containing high concentrations of boron. In this study, a sustainable treatment process was developed for wastewater containing high concentrations of boron. This study investigated the removal of boron from wastewater by Al(OH)3 sorption. The reuse of adsorbent (Al(OH)3) and the potential recovery of boric acid was the main goal of the study. It was observed that although lower concentrations of boron were obtained at pH 10.5 (980 mg/L and 635 mg/L at pH of 9.0 and 10.5, respectively), the amount of sorbed boron at pH 9 was substantially higher (94.7 mg B/g Al(OH)3 and 27.8 mg B/g Al(OH)3 at pH of 9.0 and 10.5, respectively). This was attributed to the higher initial boron concentrations and the formation of boric acid and polyborate complexes at pH 9.0. Results showed that polyborate species sorption was an outer sphere complex formation, which led to the desorption of boron as pH lowered. Adsorbed boron species to Al(OH)3 could effectively be desorbed at low pH values (pH<5.0); which allows Al(OH)3 to be used in successive adsorption studies. Approximately 55% of boron recovery from pretreated wastewater was possible with the effective reuse of adsorbent. A net profit of 2.85 $/m3 could be obtained based on the amounts of chemical consumptions and boron recovery.

Bottleneck analysis of lithium and boron recovery technologies from oil and gas produced water: a conceptual approach

Bottleneck analysis of lithium and boron recovery technologies from oil and gas produced water: a conceptual approach

Enhanced boron recovery by a new synthesized polyvinyl alcohol anchored gallic acid moiety via ethyl carbamate linker

ABSTRACT An innovative promising Gallic acid anchored poly vinyl alcohol via ethyl carbamate linker (PVA-EC-GA), was functionalized to extract boron from a tourmaline ore sample from Sikait area in South Eastern Desert of Egypt, which assaying 10.45% boron oxide. Specifications for PVA-EC-GA composite were accomplished by employing a variety of methods including XPS, FT-IR, EDX, BET, 1 H-NMR, TGA, 13C-NMR and GC-MS analyses, which assure an equitable prepare of PVA-EC-GA. Investigational measurements, namely: pH, agitation time, initial concentration of boron, composite dose, co-ions, temp. and agents of eluting, have been improved. At 25°C, pH 10, 20 min agitation and 0.0092 mol/L boron ions, PVA-EC-GA composite has an extreme uptake capacity of 43.75 mg per gram which is equivalent to 175 mg/L boron ions. From the isotherm modeling, Langmuir’s quite fitting the practical data. Conferring to kinetic modeling, pseudo-second order kinetic model well predicted the kinetics of boron ions adsorption by PVA-EC-GA giving a theoretical retention capacity of 43.86 mg/g. Thermodynamic prospects expose that the adsorption process was expected as an exothermic, spontaneous, and preferable adsorption at low temp. Boron ions can be eluted from the loaded composite, by 0.5 M H2SO4 with a 97% effectiveness

Boron continuous recovery from brines by the multicolumn simulated moving bed process with boron chelating resin

The objective of this work is to develop an advanced adsorption process to continuously recover and remove boron from brines. Firstly, the adsorption and desorption performances of boron on the commercially available N-methylglucamine resin (D403 resin) are evaluated, then, the cyclic adsorption and desorption process is investigated experimentally in the fixed bed adsorber for boron recovery from brine. It is confirmed that the cyclic process involves five steps, such as boron recovery from brine, water washing 1 to remove the retained brine, boron desorption to obtain boron-rich solution, water washing 2 to recover the retained HCl solution, and resin regeneration for the reuse. Furthermore, the seven-column simulated moving bed (SMB) process with four zones is designed and investigated experimentally. Experimental results demonstrate that boron can be recovered continuously from brine in adsorption zone, and boron-rich solution is obtained continuously in desorption zone. When the inlet brine contains a low boron content (for example 296.5 mg/L), most boron in brine can be recovered by the seven-column SMB unit with 96.8 % boron adsorption efficiency, and the discharged brine contains 8.77 mg/L boron, approximately meeting the environmental protection requirement for the limitation of boron emission. Therefore, the simultaneous recovery and removal of boron from brine can be achieved by the proposed multicolumn SMB process.

Recovery of phosphorus and other minerals from greenhouse wastewater generated during soilless tomato cultivation by means of alkalizing agents

The research was aimed at determining the possibility of recovering part of nutrients by precipitation from greenhouse wastewater (GW) from soilless tomato cultivation. Analyses included such elements as: P, S, N, Cl, Ca, Mg, K, Mo, Mn, Fe, Zn, Cu, and B. Three alkalizing agents were tested in a pH range of 6.5–12.0: Ca(OH)2, KOH, and NH4OH, which simultaneously enrich greenhouse wastewater in calcium, potassium, and nitrogen. It was determined what dose of the alkalizing agent should be used, how the composition of the treated GW will change, how much and what kind of sludge will be formed, what will be the stability and technical possibility of sediment separation, and whether the type of alkalizing agent affects the course of the process. Precipitation triggered by the alkalizing agents proved to be an effective method for the recovery of phosphorus, calcium, magnesium, manganese, and boron, while it turned out ineffective in the case of the other elements tested, including nitrogen and potassium. Phosphorus recovery depended mainly on GW pH and forms of phosphate ions corresponding to this pH, and not on the alkalizing agent type. The pH value adjustment to pH = 9 for KOH and NH4OH and to pH = 9.5 for Ca(OH)2 ensured <99 % phosphorus recovery, which corresponded to P concentration in GW below 1 mgP/L and to the applied Ca(OH)2, KOH, and NH4OH doses of 0.20 g/L, 0.28 g/L, and 0.08 g/L, respectively. The highest P contents in the sludge were determined at pH = 7 and reached 18.0 %, 16.8 %, and 16.3 % in the experimental series with Ca(OH)2, KOH, and NH4OH, respectively. The sludge volume index increase along with pH increase up to pH = 10.5 for KOH and to pH = 11 for Ca(OH)2 and NH4OH.

Study on properties of boron bearing blast furnace slag composite as shielding material for D-T neutron generator

Recovery of boron bearing blast furnace slag (B3FS) as a highly cost-effective radiation shielding material can reduce radiation hazards and protect the environment. Four different shielding configurations based on the Monte Carlo Particle Transport Program (MCNP) has been established to calculate the percentage for neutron shielding, radiation dose and neutron flux to evaluate the shielding properties of B3FS composites for Deuterium-Tritium (D-T) neutron. The properties of the B3FS composite are compared with common commercial shielding materials, include boron carbide (B4C), barite concrete, boron containing polyethylene (BPE), high-density polyethylene (HDPE), ordinary concrete, Portland concrete and lead. The results indicated that the B3FS composite has a high neutron shielding property, which is close to that of B4C, BPE, HDPE and some kinds of concrete under shielding plate configuration. The neutron shielding properties of the composite are similar to those of BPE and HDPE, and are better than other shielding materials under shielding material wrapping device configuration. Based on the results, B3FS composite can be used as a new type of neutron shielding material with excellent neutron shielding performance and environmental protection.

Crystallization in Fluidized Bed Reactors: From Fundamental Knowledge to Full-Scale Applications

A review is presented on fifty years of research on crystallization in fluidized bed reactors (FBRs). FBRs are suitable for recovery of slightly soluble compounds from aqueous solutions, as it yields large, millimeter sized particles, which are suitable for reuse and permits low liquid residence times in the timescale of minutes. Full-scale applications for water softening have been applied since the 1980s, and since then, new applications have been developed or are in development for recovery of phosphorus, magnesium, fluoride, metals, sulfate, and boron. Process integration with membrane, adsorption, and biological processes have led to improved processes and environmental indicators. Recently, novel FBR concepts have been proposed, such as the aerated FBR for chemical-free precipitation of calcium carbonate, the seedless FBR to yield pure particulate products, a circulating FBR for economic recovery and extended use of seeds, as well as coupled FBRs for separation of chiral compounds and FBRs in precipitation with supercritical fluids. Advances are reported in the understanding of elementary phenomena in FBRs and on mathematical models for fluid dynamics, precipitation kinetics, and FBR systems. Their role is highlighted for process understanding, optimization and control at bench to full-scale. Future challenges are discussed.