Recovery Of Boron Research Articles

Boron Recycling from Obsolete Propulsion Engine

A process was developed to recover boron from the chemicals of an old propulsion engine. The pellet igniter in a propulsion engine is composed of oxidizers, boron compounds and binders. In order to extract the boron compounds, an organic solvent and/or aqueous treatments were employed and followed by a sintering process. A qualitative and quantitative characterization of boron was performed by differential scanning calorimeter and thermogravimetric analyses (DSC-TGA), X-ray diffractometer (XRD), X-ray fluorescence (XRF), inductively coupled plasma (ICP) and scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM–EDX). Overall, 79.7% of boron recovery was achieved. The final purity level of boron was 94%, which is sufficiently pure to satisfy the US Military’s specifications (US-MIL-P-46994B) for the pellet igniter. From the pellets igniter (a), boron (b) and potassium nitrate (c) are purely separated.

Recovery and separation of rare earths and boron from spent Nd-Fe-B magnets

The environmental and economic benefits of recycling spent Nd-Fe-B magnets are becoming increasingly important. Nevertheless, the reprocessing of this type of material by conventional processes remains a challenge due to the difficulties of rare earth elements (REEs) and Fe separation, low products purity and large-scale generation of boron wastewater. This research presents an effective approach for the comprehensive recovery of REEs, iron and boron from Nd-Fe-B magnet wastes. Investigations of the initial roasting pretreatment showed it to be an effective method that aids the subsequent selective separation of REEs, with the most suitable temperature determined to be 800 °C. During the following selective hydrochloric acid pressure leaching of the roasted magnet, the addition of 2 g/L NaNO3 was found to significantly improve the separation of REEs and B from Fe. The results indicated that almost 99% of REEs and 97% of B could be extracted, whilst in contrast, less than 0.1% of iron dissolved, to leave a hematite rich residue. The extracted REEs were then directly precipitated as oxalates with >99% extraction and 99.95% purity at a value n(oxalic acid)/n(REEs) of 1, resulting in significant improvements to oxalic acid consumption and REEs product purity. In the final step, 99.5% of boron was recovered via a three-stage counter current extraction with 30% (v/v) (EHD) and 70% (v/v) sulfonated kerosene. These findings demonstrate that high recoveries of REEs, Fe and B are achievable with hydrochloric acid pressure leaching followed oxalate precipitation and boron recovery.

Graphene oxide modified porous P84 co-polyimide membranes for boron recovery by bipolar membrane electrodialysis process

Composite anion-exchange membranes with porous structures have been successfully prepared by incorporating quaternized graphene oxide (QGO) into P84 co-polyimide, and then undergoing the phase inversion, amination and quaternization processes. The membranes’ porous structures can be readily adjusted by the category of non-solvent during the phase inversion process. Large finger-like voids are present in the lower parts of the membrane cross sections by using water or 50% isopropanol aqueous solution, which facilitate the entrance of polyethylenimine chains into the membrane matrix, leading to higher degree of amination and quaternization. The incorporation of QGO does not influence the membrane morphology obviously, but can further enhance the ion exchange capacity (1.23–1.65 mmol/g) and decrease the membrane area resistance (1.6–1.9 Ω cm2).The QGO-P84 composite membranes are used in bipolar membrane electrodialysis (BMED) for the removal of boron from synthetic model solutions (Na2B4O7·10H2O, 1000 mg B/L). The finger-like pores decrease the steric resistance of boron transport, while the incorporation of QGO improves the membrane electro-chemical properties and thus the BMED performances. The separation efficiency is 76.6% after running 3 h under 30 V, the current efficiency is 94.9% and the energy consumption is 26.16 kW h/kg by using the optimal composite membrane. The BMED performances are better than those of commercial membrane CJMA-3 (separation efficiency of 51.6%, current efficiency of 81.2%, and energy consumption of 30.56 kWh/kg). Hence, the QGO-P84 composite membranes are effective for removal and recovery of boron from aqueous solution through BMED method.

Simultaneous Recovery of Display Panel Waste Glass and Wastewater Boron by Chemical Oxo-precipitation with Fluidized-Bed Heterogeneous Crystallization.

Silica-based carrier is a promising material for recovery of metal and nonmetal contaminants in chemical oxo-precipitation-fluidized bed crystallization (COP-FBC) system. Boron species are an essential element for plant growth and can cause health concerns in human beings at high concentrations in water environments. The composition of thin-film transistor liquid crystal display (TFT-LCD) contains a wide variety of metal oxides and can be tailored as promising functional mesoporous carriers for boron crystallization recovery in the presence of barium ions and hydrogen peroxide. In this study, waste-derived mesoporous aluminosilicate (MAS) nanomaterial in the presence of barium ions and hydrogen peroxide was used as a carrier for sustainable recovery of crystallized boron, a priority wastewaters pollutant. The MAS shows the hierarchically homogeneous distribution of nanostructured aluminosilicate particles with an average size of 12.8 ± 3.6 nm on the surface after the activation with Na2CO3 at 1000 °C. Moreover, the negatively charged surface and the mesoporous structure of MAS enhance the adsorption of Ba2+ onto MAS, and the Langmuir adsorption capacity of 105 mg/g is achieved, which is conducive to the enhancement of the recovery of boron species. Moreover, the recovery efficiency and crystallization ratio of boron by MAS can be up to 84.5 and 93.4%, respectively. The cross-sectional scanning electron microscopy images and the high-temperature X-ray diffraction results confirm the boron recovery mechanism that the negatively charged functional group as well as the mesoporosity of MAS triggers the rapid formation of needle-shaped precipitates of barium peroxoborate, and then converted to barium borate after calcination at 1050 °C. Results obtained in this study clearly demonstrate the possibility of fabricating environmentally benign mesoporous aluminosilicate adsorbents from TFT-LCD waste to sustainably recover and crystallize boron species from water and wastewater in COP-FBC.

Effect of Cryolite on Microstructure of Insitu AlB2 Aluminium Metal Matrix Composites

Todays composite material have gained more popularity due to their improved properties over the conventional materials. In the present paper, insitu composites were fabricated via chemical reaction between molten aluminium alloy and halide salt KBF4 with cryolite at 8000C by stir casting method. The microstructures of the composite containing 3 and 5 wt. % of AlB2 reinforcement phase have been compared with the unreinforced aluminium alloy. The microstructure analysis shows clean AlB2 particles uniformly distributed throughout the matrix. With the increase in the AlB2 reinforcement, insitu composite show less agglomeration and recovery of boron is more when compared to the unmixed halide salt in the fabrication of inistu composite

Bioinspired modified nanocellulose adsorbent for enhanced boron recovery from aqueous media: Optimization, kinetics, thermodynamics and reusability study

In this current study, platelet-shaped gels of amino modified nanocellulose (A-NCC) were facilely prepared and applied for the enhanced recovery of boron from aqueous media. The gels were characterized using FTIR, XRD, SEM, BET, TGA and the results revealed good thermal as well as mechanical stability. Optimization by Taguchi design model was further applied to investigate the significance of input adsorption factors influencing boron recovery from aqueous phase. Under optimized conditions, 87.38% (≈120.9 mg boron/g of A-NCC) boron recovery was achieved at pH 7. Kinetic evaluations determined the pseudo 2nd-order model (R2 = 0.997) to best describe the adsorption process mainly via intraparticle diffusion. Thermodynamic studies confirmed the adsorption process was spontaneous and exothermic in nature. In addition, reusability capacity of the adsorbent proved significant for at least four consecutive adsorption/desorption cycles with minimum recovery efficiency loss.

Production of the Al–B master alloy by KBF4and B 2O3aluminothermic reduction in molten salt flux medium

The study covers the process of obtaining the Al–B master alloy by the KBF4and B2O3aluminothermic reduction using KF–AlF3and KF–NaF–AlF3fluoride fluxes at 983 and 1123 К, respectively, and KCl–NaCl–KF chloride-fluoride fluxes at Т= 1173÷1223 К. All experiments were carried out under the same conditions: molten mixture stirring rate was 400 rpm, synthesis duration was 30min. The maximum amount of boron (1,5 %) in the Al–B alloy was obtained when using KBF4(3 % per B) as a boron-containing raw material in the KF–AlF3medium with a molar (cryolite) ratio (CR) of KF/AlF3equal to 1,3, atТ= 983 К, while boron recovery ratio did not exceed 75 %. Comparable results were obtained in experiments with KF–NaF–AlF3f lux (CR = 1,5) at Т= 1123 К. However, with the increased concentration of fed boron its recovery ratio decreased substantially. It is connected with the higher decomposition temperature of not only KBF4, but also less thermally stable NaBF4 formed as a result of exchange reaction in the melt. Therefore it is not recommended to use sodium salts as a f lux component. The Al–B master alloys obtained by KBF4reduction in fluoride fluxes were solid solutions of B in Al containing the AlB2intermetallic compound. The lowest amount of boron in aluminum with the minimum degree of extraction was obtained in experiments with the B2O3in molten KF–AlF3with CR = 1,5. Nevertheless, the results of scanning electron microscopy indicate a uniform distribution of B over the Al matrix and the absence of intermetallic compounds, while a large amount of Al2O3was found, which is the product of B2O3reactions with both liquid Al and KF–AlF3flux.

Metallothermic Production of Boron-containing Silicon Barium

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Stabilization of Self-slaking Slags from Ferroalloy Production

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Boron recovery from separate of Pauzhetskaya geothermal station based on modified zeolites of Yagodninsky deposit of Kamchatka

Experimental data on boron sorption from separate of Pauzhetskaya geothermal station by sorbents obtaining by directional modification of zeolites surface of Kamchatka Yagodninsky deposit are presented. The modification was carried out with urotropine (ZEO-UB) or mannite (ZEO-MB). It was determined, that sorbent ZEO-MB has better properties in comparison with ZEO-UB. Sulfate-ions concentration does not affect on sorption capacity; chloride-ions concentration effects negligible. The sorbent is selective relative to boric acid due to reaction of mannite-boric acid formation. Sulfate-and chloride-ions greatly influence on H3BO3 chemosorption with ZEO-UB due to reaction of amino radicals salification with amines of urotropine.

Pyrohydrolysis separation of percentile level boron in borated Zr-Nb alloy and its determination by ion chromatography

ABSTRACTA pyrohydrolysis method has been developed for separating percentile level boron in borated Zr-Nb alloy. The pyrohydrolytic behaviour of this alloy was studied and the optimum separation conditions required for achieving complete recovery of boron were identified. Zr-Nb alloy turnings (thickness < 0.1 mm) were subjected to pyrohydrolysis at 1,230°C for 120 min with moist oxygen carrier gas at a flow rate of 2 L/min. The pyrohydrolysis distillates were analysed by ion chromatography (5 mM NaOH and d-mannitol as eluent) for boron quantification. The method showed an external precision better than 2.5%.

Recovery of Boron from Underground Brine by Continuous Centrifugal Extraction with 2-Ethyl-1,3-hexanediol (EHD) and Its Mechanism

In order to economical and environmental-friendly recycle of boron from underground brine, the extraction of boron was carried out in this work by the continuous centrifugal technique using 2-ethyl-1,3-hexanediol (EHD) + sulfonated kerosene (SK) extraction system, and the extraction mechanism was also investigated by the combination of FT-IR with slope method. The results showed that boron can be effectively extracted from underground water with the concentration of boron 5.43 g·L−1 by five-stage centrifugal extraction using 30% EHD + 70% SK at pH = 2.0–3.0, R(O/A) = 1 : 2, and the extraction rate reached 98.46%. Boron in the organic phase can be well five-stage back-extracted by 1.0 mol·L−1·NaOH at R(O/A) = 1 : 1 with a back-extraction rate of 97.00%. About 88.32% boron in the aqueous phase obtained by back-extraction can be recycled in H3BO3 form by evaporation crystallization after acidified to pH &lt; 2.5. The extraction mechanism indicated that the extraction is completed mainly based on the esterification reaction between alcoholic hydroxyl in EHD and -OH in B(OH)3 at the stoichiometric ratio 1 : 1 to generate a stable six-membered ring structure of boric acid ester.

Effect of acid-base solutions used in acid-base compartments for simultaneous recovery of lithium and boron from aqueous solution using bipolar membrane electrodialysis (BMED)

Application of bipolar membrane electrodialysis (BMED) for simultaneous separation and recovery of lithium and boron from aqueous solution was investigated using Astom Acilyzer EX3B model ED device. In the laboratory scale experiments performed, effects of acid and base solutions types and their concentrations employed in acid and base compartments, electrical potential applied on process efficiency were investigated. The results showed that separations and recoveries of both boron and lithium were effective when 0.05 M HCl and 0.05 M NaOH solutions have been used in acid and base compartments, respectively. The percent separations of boron and lithium were 86.9% and 94.7%, respectively, while their respective recoveries were 50% and 62% at 30 V. The maximum separation and recovery values for boron and lithium were obtained when a 30 V of electrical potential was applied. With optimal initial acid and base concentrations (0.05 M) used in acid and base compartments, the specific power consumption (SPC) was calculated as 7.9 kWh/m3 at 30 V.While higher initial acid and base concentrations showed higher boron and lithium separation efficiencies, relatively lower concentrations of acid and base solutions employed in acid and base compartments improved the recoveries of boron and lithium. Acid and base solutions generating a moderate conductive medium in acid and base compartments improved separations along with recoveries of boron and lithium from solution. When the solutions of 0.1 M HCl and 0.1 M NaOH were used in acid and base compartments, recoveries of boron and lithium were 27% and 33%, respectively. On the other hand, the recoveries of boron and lithium were 62% and 56%, respectively when 0.1 M H3BO3 and 0.1 M LiOH solutions were employed in acid and base compartments.

Simultaneous removal and recovery of boron from waste water by multi-step bipolar membrane electrodialysis

We have developed bipolar membrane electrodialysis (BPED) for simultaneous removal and recovery of boron from waste water. BPED is performed with a two-cell electrodialysis unit composed of an anion exchange membrane (AEM) sandwiched between two bipolar membranes (BPM). A semi-batch type operation was performed by circulating solutions through the cells, namely, the removal and concentration cells. The volume ratio of the reserve tanks for the feed stream to the cells was set to 4:1 (removal: concentratation). Tetrahydroxyborate ions were transported from the removal cell to the concentration cell through the AEM. In the ideal case, the boron concentration in the concentrate should be concentrated to 5 times the initial concentration, when the solutions of the same initial concentration were supplied to both cells of concentration and removal. The concentrated solution was then used for second step to further concentrate the solution. This concentrated solution was then used for third step, and so forth. The operation was continued step-by-step until the boron concentration was sufficiently high to easily recover boric acid. The experimental results with a stack of five cells for the sodium borate solutions (initial concentration: 100 mg/L) showed that the boron concentration in the concentrate was about 4, while that in the diluate was less than 10 mg/L, which is below the regulatory value for waste water in Japan. After four steps, the boron concentration in the concentrate reached close to the solubility of boric acid (ca 10,000 mg/L), at which boron can be recovered for recycling.

Application of bipolar membrane electrodialysis (BMED) for simultaneous separation and recovery of boron and lithium from aqueous solutions

Simultaneous separation and recovery of lithium and boron from the aqueous solution prepared by dissolving lithium tetraborate using bipolar membrane electrodialysis (BMED) was studied to investigate the effect of applied potential and initial concentrations of lithium and boron as well as co-existing ions in the solution. The results revealed that mass transfer rates of lithium and boron increased with applied voltage up to a maximum limit voltage. Good linear correlation between initial concentrations and transfer rates of lithium and boron was helpful to elucidate the mass transfer mechanism which can be explained by Fick's first law of diffusion. The permeation of lithium and boron through the membrane were little bit affected by the applied voltage and also by the initial concentrations of lithium and boron. The influence of co-existing sodium or chloride ions on the BMED performance was not observed. The separation efficiencies of lithium and boron were quite high with a BMED performance >90%. The current efficiency of lithium and boron gradually decreased with an increase in the applied voltage while specific power consumption increased with an increase in the applied voltage.

Research on boron recovery from sulfate-type saline lakes with a novel dilution method

A novel dilution method was developed to extract boron from sulfate-type salt lake brine in the Qinghai Tibet plateau. The boron-concentrated brine was prepared by evaporation after magnesium removal using Na2SO4·10H2O solid. The extraction process parameters such as boron concentration, dilution ratio, temperature, initial precipitation time, aging time, and extraction efficiency of boron were tested. The results showed that the solution pH after dilution with deionized water increased from 4.2 to 8.0, indicating dissociation of polyborate ions in brine by hydrolysis to give monoborate species and hydroxide ions. The initial precipitation time and aging time were observed to be strongly influenced by the boron concentration, dilution ratio, and temperature. A low temperature, high boron concentration and moderate mass dilution ratio (water/brine) were beneficial to boron extraction, allowing for an extraction efficiency of more than 80%. The only salts that precipitated from diluted brine were magnesium borates. The obtained results indicated the application potential of the novel technology of boron extraction from salt lake brine.

Effect of process conditions on recovery of lithium and boron from water using bipolar membrane electrodialysis (BMED)

Electrodialysis (ED) combined with bipolar membrane, a new system known as bipolar membrane electrodialysis (BMED) has been developed to separate ions from aqueous saline solutions and recover them in their corresponding acids and bases. In this study, separation and recovery of lithium and boron from aqueous solution by BMED method was investigated. Lithium and boron were recovered as LiOH and H3BO3 with BMED, respectively. The influence of process conditions such as applied potential, initial sample volume and pH on BMED performance was monitored. The performance of BMED method increased with an increase in applied voltage but decreased with an increase in initial sample volume. At optimum conditions of 15V and 0.5L as initial sample volume, separation and recovery of lithium were 99.6% and 88.3%, respectively, while the respective values for boron were 72.3% and 70.8%. An increase in pH improved separation and recovery of boron more than those of lithium. At pH12.25, separation and recovery of boron were 95.6% and 78.8%, respectively. The BMED method was found to be effective for simultaneous separation and recovery of lithium and boron from same aqueous solution at optimum operating conditions.

Targeted boron removal from highly-saline and boron-spiked seawater using magnetic nanobeads: Chemometric optimisation and modelling studies

Chitosan-based magnetic nanobeads (CBN) were facilely synthesised and applied for selective recovery of boron from highly-saline wastewater. The CBN was characterised, and the results showed that the nanobeads are thermally and mechanically stable to withstand deterioration, had a saturation magnetisation of 65.25emu/g, the surface area of 635m2/g and nanobeads size of ∼2.6–3.8nm. An artificial neural network (ANN) model and Box-Behnken design (BBD) were developed and applied to study the relative effect and significance of input variables affecting boron sorption. Under optimised conditions, 89, 78 and 70% boron removal efficiencies were recorded at pH 7.0 in distilled water, highly-saline water and boron-spiked seawater respectively. The combination of intraparticle diffusion model and pseudo-second-order rate equation was applicable to describe the sorption kinetics.

Recovery of boron from high-boron iron concentrate using reduction roasting and magnetic separation

The comprehensive utilization of abundant high-boron iron concentrate is of particular significance to China, and the high-boron iron concentrate has not yet been utilized as a source for boron at an industrial scale due to its complex mineralogy and fine mineral dissemination. An innovative method was proposed for recovery of boron and iron from high-boron iron concentrate by reduction roasting and magnetic separation. The effects of reduction temperature and roasting time were investigated and their optimum conditions were determined. The mineralogical changes during roasting were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results showed that the pyrrhotite (FeS) contained in the high-boron iron concentrate and the new-formed FeS-Fe solid solution softened or melted at high temperatures owing to their low melting points, and then decreased the metallic iron ratio and accelerated the growth of metallic iron particles. Meanwhile, the magnetite and szaibelyite were converted into metallic iron and suanite, respectively. Consequently, boron was readily enriched into the non-magnetic product and the metallic iron was aggregated to the magnetic concentrate by magnetic separation. Boron recovery of 88. 6% with corresponding B2 O3 content of 14. 5% and iron recovery of 95. 1% with an iron grade of 92. 7% were achieved when high-boron iron concentrate was reduced at 1125 °C for 150 min. Besides, the boron reactivity of the boron-rich non-magnetic product was up to 80. 8%.

Pyrocatechol-modified resins for boron recovery from water: Synthesis, adsorption and isotopic separation studies

Two kinds of pyrocatechols, pyrocatechol (CL) and nitropyrocatechol (NCL), were chosen by the conductive value change (Δ) they cause in the boric acid-polyol solutions, and corresponding modified resins (CL-RESIN and NCL-RESIN) were synthesized by new methodology for effective boron removal and isotopic separation. The optimized boron adsorption occurs at pH=9.06 for CL-RESIN, and pH=6.70 for NCL-RESIN, with the maximum adsorption capacity 0.7886mmol·g−1 and 0.7931mmol·g−1, which were comparable to commercial IRA 743. Boron adsorption on prepared resins was saturated within 12h and can be well described by pseudo-second-order kinetic model. Freundlich isotherm model fits well at low boron concentration while Langmuir isotherm model fits better at high concentration. Furthermore, the boron isotopic separation factors S on two prepared resins are 1.080 for CL-RESIN and 1.140 for NCL-RESIN, which are far higher than all previous results. Boron removal and isotopic separation capacities make it possible that three problems, boron removal, isotopic separation and boron reusability, can be addressed in single adsorption process.