Recovery Of Gallium Research Articles

Behaviors of Adsorption and Elution on Amidoxime Resin for Gallium, Vanadium, and Aluminium Ions in Alkaline Aqueous Solution

ABSTRACT For recovery of gallium from Bayer liquor, adsorption, and elution on amidoxime resin for gallium (Ga), vanadium (V), and aluminum (Al) ions in alkaline solution were systematically investigated by batch and column experiment. Amidoxime resin did not adsorb Al. The adsorption separation efficiency of Ga and V increased with increasing NaOH concentration and decreasing temperature and contact time. The adsorption kinetics of Ga and V are fit by a pseudo-second-order model. The adsorption isotherms of Ga and V could be fit well by the Langmuir model. Gallium was easily eluted using low concentration acid (1~2 mol/L H+), but it was difficult to elute V. Although high concentration acid could elute 70% of V, this treatment would destroy resin. With high NaOH concentration and a long eluting time, more than 50% of V could be eluted at temperatures greater than 50°C, and NaOH did no damage to the resin. The optimum condition of Ga separation from V and Al is at low temperature with short contact time and high NaOH concentration. After adsorption and desorption, a high-purity Ga is obtained, from which V can be recovered V by elution with a strong NaOH concentration at 50°C. FT-IR spectra and XPS showed that the adsorption mechanism of Ga was only related to interaction with oxygen atoms of amidoxime groups (C = NOH). Furthermore, the adsorption mechanism of V was related to both nitrogen and oxygen atoms of amidoxime groups that caused the difficulty of desorbing V from resin.

Recovery of Gallium from Smartphones—Part II: Oxidative Alkaline Pressure Leaching of Gallium from Pyrolysis Residue

In this article, we examine the selective hydrometallurgical extraction of gallium from pyrolyzed smartphones. Gallium-enriched pyrolysis residue originating from pyrolyzed smartphones was leached using NaOH and gaseous oxygen at elevated temperatures and pressures. The high content of organic carbon in the material strongly influenced the leaching performance. Oxygen, which is indispensable for the dissolution of gallium, also oxidized the organic carbon in the feed so that CO2 was released, which had a neutralizing effect on the alkaline solution. As a result, the CO2 formation complicated the accurate process control as the leaching temperature increased. The highest gallium yield of 82% was obtained at 180 °C, 5 g/L NaOH and 5 bar oxygen pressure. Decreased temperatures, NaOH concentrations and oxygen pressures resulted in lower leaching yields but with a higher selectivity for Ga. Temperatures higher than 180 °C resulted in extensive carbon oxidation, NaOH consumption and the coextraction of Cu and Ag. We propose that those conditions also facilitated the formation of water-soluble organic compounds, which would also influence the metal dissolution.

Recovery of gallium from yellow phosphorus flue dust by vacuum carbothermal reduction

Yellow phosphorus flue dust (YPFD) is a kind of solid waste generated from yellow phosphorus production. Because it contains approximately 0.05% of gallium (Ga), the recovery of Ga from YPFD has attracted the interest of many researchers. To reduce environmental pollution and storage problems associated with YPFD, a new vacuum thermal reduction method to recover Ga from YPFD was proposed in this study. Thermodynamic calculations and thermogravimetric analysis were first used to determine the initial reaction temperature between Ga2O3 and C. High-purity Ga2O3 and activated carbon were evenly mixed and heated at 1273 K and 10 Pa for 2 h. Experimental results showed that metallic Ga could be obtained in the condensation zone by vacuum carbothermal reduction. Based on this result, we next attempted to recover Ga from YPFD by vacuum carbothermal reduction. YPFD containing 30 wt% carbon was heated at 1273 K and 10 Pa for 2 h, and the experimental results also yielded Ga enrichment in the condensation zone. Therefore, this study provides a new and potential useful technology for recovery of Ga from YPFD, as well as a certain practical approach to comprehensively utilizing such industrial waste.

Uniform macroporous amidoximated polyacrylonitrile monoliths for gallium recovery from Bayer liquor

AbstractEfficient recovery of gallium from aqueous solution remains a problem to be solved in industry. Here a novel crosslinked monolith based on polyacrylonitrile/dimethyl sulfoxide (C‐PAN) was prepared by thermally induced phase separation and supercritical CO2 extraction drying technology. The influences of dissolution temperature and exchange solvents with different solubility parameters on the pore structure of C‐PAN were systematically studied. It was found that the pore diameter decreased with the decrease of dissolution temperature and the increase of Δδ between exchange solvent and PAN. Meanwhile, the C‐PAN with a small and dense pore structure showed better mechanical strength. Thereafter, the Ga3+ adsorption ability of amidoximated monolith (C‐PAO) in simulated Bayer liquor was determined by batch tests. In the case of using methanol as the exchange solvent, the kinetic and equilibrium inspection study illustrated that both physical and chemical adsorption are present due to the multiscale and interconnected structure and the amidoxime groups. The adsorption capacity of C‐PAO monolith toward gallium was 15.8 mg/g, with the equilibrium time as fast as 140 min, which can meet the requirement for the rapid extraction of gallium from Bayer liquor. It is expected that our work can provide some new ideas for fabricating gallium adsorbents.

Recovery of gallium by silica‐based polymer TBP/SiO2‐P obtained from hydrochloric acid solution

AbstractResin adsorption methods are widely used to recover gallium (Ga) from Bayer liquid. However, when the resin adsorbs Ga(III), a part of vanadium (V), magnesium (Mg), silicon (Si), calcium (Ca), and aluminum (Al) were coextracted with Ga and then was eluted together by using hydrochloric acid (HCl) solution. These impurities would affect the recovery of high‐purity Ga by electrolysis. Ga‐bearing acid eluted solution treatment followed by secondary adsorption was used to purify Ga(III) by a porous silica‐based adsorbent tributyl phosphate (TBP)/SiO2‐P. The adsorption properties of Ga(III) by TBP/SiO2‐P from HCl were investigated. TBP/SiO2‐P exhibits significantly high selectivity toward Ga than other impurities with SFA/B is 3478 in 8 mol/L HCl solution. The adsorption capacity reaches 22.01 mg/g and adsorption equilibrium was obtained within 5 min. Moreover, Ga(III) is easy to be eluted by ultrapure water with a rate of 95.58%. The adsorption kinetics and isotherms of Ga fit well with the pseudo‐first‐order model and Langmuir adsorption model, respectively. TBP/SiO2‐P is an excellent material to recover Ga(III) from HCl solution effectively and efficiently. Moreover, this work provides a potential candidate for purifying Ga from Bayer liquor by the two‐step method (purify and adsorb the desorption liquid containing Ga hydrochloride).Highlights A silica‐polymer based adsorbent TBP/SiO2‐P was prepared through a simple vacuum impregnation method and use to purify Ga from Bayer liquor by the two‐step method. A simple and efficient method for Ga purification was proposed with a high‐adsorption capacity and short equilibrium time. In the coexisting ions mixed solution, TBP/SiO2‐P has a high‐selective toward Ga(III), Ultrapure water can effectively desorb Ga from adsorbent with the desorption rate of about 95.58%.

Production of polyacrylonitrile nanofibres modified with Cyanex 272 for recovery of gallium from solution

ABSTRACT The objectives of this work were to develop polyacrylonitrile nanofibres modified with the commercial Cyanex 272 extractor and apply them for the recovery of gallium present in aqueous solution. The nanofibres were produced using the centrifugation technique, employing Forcespinning® equipment. The average nanofibre diameter ranged from 530 to 840 nm. The highest adsorption of gallium was achieved at pH 2.5, with a pseudo-second order kinetic model and the Freundlich equilibrium isotherm model providing the best fits of the experimental data. The thermodynamic parameters showed that the adsorption was spontaneous, favourable, and endothermic. The maximum capacity of the PAN/Cyanex 272 nanofibres for the recovery of gallium was 38.93 mg g−1. In successive reuse cycles, the nanofibres showed a small decrease of the adsorption capacity for the metal after the first cycle, while the efficiency remained constant in the subsequent cycles. The desorption efficiency remained constant throughout the cycles, with values in the range 80%–90%. The findings demonstrated that PAN/Cyanex 272 nanofibres have excellent potential for use as adsorbents, providing good capacity for the recovery of gallium and satisfactory stability during reuse in several cycles.

A new method of recycling gallium from yellow phosphorus flue dust by vacuum thermal reduction process

Gallium is widely used in the field of semiconductors, and is mainly recovered as a by-product from other production processes utilizing metals such as aluminum and zinc. As a waste generated during the production of yellow phosphorus, yellow phosphorus flue dust is a potential resource for recovery of gallium. In this study, vacuum carbothermic reduction technology was applied to extract gallium from yellow phosphorus flue dust. Under the optimal conditions of 1323 K, 40 min holding time, 50 wt% carbon content, and 1−10 Pa, the recovery rate of gallium was 92.5 %. The condensate was analyzed and the enrichment area of gallium in the condensation zone was determined. No hazardous gases and materials were generated during the process. Compared with other methods of recovering gallium from yellow phosphorus flue dust by hydrometallurgical process, this study has the advantages of short process, easy collection of products, low energy consumption. Overall, this work demonstrates a new and environmentally friendly method for the recovery of gallium from yellow phosphorus flue dust, and also provides a reference value for the comprehensive utilization of this material.

Recovery of Gallium and Indium from Waste Light Emitting Diodes†

Recovery of gallium and indium from waste light emitting diodes has been emphasized gradually owing to high content of gallium and indium. This study was established the recovery of gallium (Ga3+) and indium (In3+) from waste gallium nitride was contained in waste light-emitting diodes. The procedure was divided into the following steps; characteristic analysis, alkaline roasting, and leaching. In characteristic analysis part, the results were used as a theoretical basis for the acid leaching part, and the chemical composition of waste light emitting diodes is 70.32% Ga, 5.31% Si, 2.27% Al and 2.07% In. Secondly, with reduction of non-metallic components by alkaline roasting, gallium nitride was reacted into sodium gallium oxide, in this section, the optimal condition of alkaline roasting is that the furnace was soaked at 900°C for 3 hours with mixing Na2CO3. Next, leaching of waste light emitting diodes was extremely important in the process of recovery of gallium and indium. The result of leaching efficiency was investigated on the optimal condition accounting for the acid agent, concentration of acid, the ratio of liquid and solid, and reaction time. The optimal condition of leaching procedures was carried out for 2.0M of HCl liquid-solid mass ratio of 30 ml/g in 32minutes at 25°C and about 96.88% Ga and 96.61% In were leached.

Recovery of Gallium from Simulated GaAs Waste Etching Solutions by Solvent Extraction

Gallium arsenide is used in semiconductor industries worldwide. Numerous waste etching solutions are produced during the processes of GaAs wafer production. Therefore, a complete and eco-friendly technology should be established to recover gallium as a gallium chloride solution and remove arsenic ion from waste GaAs etching solution. In this study, the gallium trichloride and arsenic trisulfide powders were dissolved in ammonia solutions to prepare the simulated solutions, and the pH value was adjusted to pH 2 by nitric acid. In the extraction step, the GaAs etching solutions were extracted using 0.5 M Cyanex 272 solutions in kerosene at pH 2 and 0.1 O/A ratio for 5 min. The extraction efficiency attained 77.4%, which had an optimal ratio of concentration, and the four steps extraction efficiency attained 99.5%. After extraction, iron sulfate heptahydrates were added into the raffinate, and the arsenic ions were precipitated. The removed rate attained 99.9% when the Fe/As ratio was 10. In the stripping step, the organic phase was stripped with 0.5 M hydrochloric acid at 1 O/A ratio for 3 min, and 97.5% gallium was stripped. Finally, the purity of gallium chloride solution was 99.95% and the gallium was seven times the concentration of the etching solutions.

The extraction of gallium from chloride solutions by emulsion liquid membrane: Optimization through response surface methodology

Emulsion liquid membrane was used to extract gallium from a chloride medium. The influence of several critical parameters including, carrier concentration, surfactant concentration, the ratio of the internal phase to the membrane, agitation speed and their interactions on gallium recovery were investigated. A response surface methodology based on a Box-Behnken design was used to find out optimum conditions and determine the interaction effects of parameters. The liquid membrane including a diluent (kerosene), a surfactant (sorbitan monooleate), a carrier (tri-isobutyl phosphate), and 0.1 M sulfuric acid as the stripping solution was used. Maximum gallium recovery (94.6%) were obtained at the carrier concentration of 5.8% (v/v), the surfactant concentration of 3.2% (v/v), the ratio of the internal phase to the membrane of 1.1 and the agitation speed of 245 rpm. The gallium recovery increased with an increase in the level of the investigated parameters, and after reaching the optimum conditions, it decreased. A predictive model was proposed to predict the gallium recovery from the chloride solution by emulsion liquid membrane. The results indicated that the gallium can be effectively recovered from the chloride solution using emulsion liquid membrane with tri-butyl phosphate (TBP) as a carrier.

Recovery of gallium from waste LEDs by oxidation and subsequent leaching

In this paper, gallium recycling from waste light emitting diode (LED) by oxidation and subsequent leaching was studied. Gallium is present in the LED chip as gallium nitride. Disassembling and crushing of the LEDs were carried out after burning the polymeric parts, and then the chip is separated from the LED. Leaching of the gallium from the chips was performed after oxidation step at optimum temperature of 1100 °C. The oxidation heat treatment was carried out at 1000, 1100 and 1200 °C and the oxidation mechanism was studied in detail. Oxidation causes depletion of nitrogen gas and absorption of oxygen atoms by the gallium nitride structure, which results in the formation of a porous oxide structure. The minimum transformation temperature of gallium nitride to gallium oxide, was 1100 °C. In the final oxide phase, comparison of the structure and morphology of the chip surface after oxidation at 1200 °C and 1100 °C shows that at higher oxidation temperature the surface area decreases and the grain size increases. Changing the solubility of the phase containing the gallium by oxidation at different temperatures considering has been investigated. Leaching experiments were designed using design of experiment (DOE) method. At optimum leaching conditions of 4 M hydrochloric acid, 93 °C and 120 min, the gallium leaching recovery was 91.4%. Based on the results, leaching temperature is the most effective parameter in this process.

A Process for the Recovery of Gallium from Gallium Arsenide Scrap

The recovery of gallium (Ga) from gallium arsenide (GaAs) scrap using a leaching-ion exchange method was investigated. The ground GaAs scrap was leached, using 2.0 N nitric acid at 30 °C for 1.0 h, and the dissolution of Ga and arsenic (As) reached 98%. The pregnant solution with a 1/20 dilution ratio was then passed through a weak acid chelating resin Diaion CR-11. Highly charged Ga3+ has the ability to form complexes with the chelating resin and separate from the coexisting H3AsO4 in the leachate with very low pH. The loaded column was eluted with 0.1 M H2SO4, and the final concentrated solution had 4.5 g/L of Ga with 99.3% purity. The effluent from the column was further processed to remove As by ferric arsenicate precipitation, and reused continuously as the dilution water for raw leachate.

Highly efficient and selective recovery of gallium achieved on an amide-functionalized cellulose

Highly efficient and selective recovery of gallium achieved on an amide-functionalized cellulose

Investigation on the Effect of Roasting and Leaching Parameters on Recovery of Gallium from Solid Waste Coal Fly Ash

Coal fly ash (CFA) provides important resources of gallium, which is regarded as an irreplaceable material in many technologies. A prospective roasting reagent assisted acid leaching process was proposed for the purpose of extracting gallium. The extraction efficiency of gallium by NaF (sodium fluoride) roasting followed by HNO3 (nitric acid) leaching process was demonstrated. The effect of roasting temperature, roasting time, the NaF-CFA mass ratio, acid leaching temperature, acid leaching time, and acid concentration were investigated. The results revealed that under optimal conditions (roasting temperature of 800 °C, roasting time of 10 min, acid leaching in 2 mol/L HNO3 for 1 h, and the NaF-CFA mass ratio of 0.75:1), 94% of gallium was extracted. Compared to previous studies, the process is a cost-effective method which can greatly shorten reaction time. It can reduce environmental pollution as it requires fewer acid reagents with low concentration and additives. It is expected to provide a method for the extraction of gallium from CFA.

Recovery of gallium from sulfuric acid leach liquor of coal fly ash by stepwise separation using P507 and Cyanex 272

For the ever-growing demand of gallium (Ga) resources in electronic applications, the recovery of Ga from the mining residues or waste has received considerable interest. The present paper is focused on the selective recovery of Ga from the sulfuric acid leach liquor of coal fly ash (CFA) by stepwise separation using acidic extractant. The results show that Ga(III) can be effectively separated by controlling the equilibrium pH values and meanwhile employing appropriate extractant based on the different ionic potential and electronic configuration of metal ions. At equilibrium pH ≤ 0.8, the impurities Ti(IV) and Fe(III) in the liquor can be preferably removed by a two-stage cross current extraction with 1 mol/L P507. Then Ga(III) can be selectively separated against Al(III) using 0.5 mol/L Cyanex 272 at equilibrium pH of 2.4–2.6. The separation factors of Fe/Ga, Fe/Al and Ga/Al can reach 145, 133 and 40, respectively. The extraction mechanism of Ga(III) as well as the Ga(III) complexes with Cyanex 272 were investigated using slope analysis and spectroscopic methods including FT-IR, NMR and ESI-MS, indicating that the extraction of Ga(III) with Cyanex 272 follows an ion exchange mechanism. The Ga(III) complexes with Cyanex 272 (H2L2) contains three coordination compounds, GaL3, Ga(HL)L3 and Ga(HL)3L3. Both the P-O and P = O groups of Cyanex 272 play the roles in the coordination reaction of Ga(III). The study provides a feasible way for the selective recovery of Ga from coal fly ash.

Polyacrylic acid-functionalized graphene oxide for high-performance adsorption of gallium from aqueous solution

Graphene oxide (GO) has great potential in metal recovery and water purification owing to their high surface area, abundant hydroxyl (OH) and carboxyl (COOH) groups. To fully understand the influence of the dispersity of GO on the adsorption capacity of metal ions, a series of polyacrylic acid (PAA) functionalized GO (PAA/GO) composites with different dispersity were prepared. The charge density of the PAA/GO composites were much higher than that of the untreated GO in acidic conditions, demonstrating a significant improvement of dispersibility by introducing PAA on the surfaces. Moreover, recovery of gallium by employing the PAA/GO composites as adsorbent were studied. The maximum adsorption capacity towards gallium ions of the adsorbent can reach 196.84 mg·g−1, much higher than that of other commercially available resins (CL-P204, P507). This superiority could be attributed to the abundant COOH groups on the surfaces and the good dispersity of the PAA/GO composites. These results revealed that the PAA/GO composites could be promising adsorbents for selective adsorption and efficient recovery of Ga(III).

Recovery of Gallium, Indium, and Arsenic from Semiconductors Using Tribromide Ionic Liquids

Leaching of semiconductors (GaN, GaAs, and InAs) and light-emitting diodes (LEDs) in a nonvolatile tribromide ionic liquid, and the selective recovery of gallium, indium, and arsenic from this ioni...

Recovery of Gallium from Bauxite Residue Using Combined Oxalic Acid Leaching with Adsorption onto Zeolite HY

Bauxite residue, the byproduct of alumina production, may potentially be a valuable source of strategically important metals, e.g. Gallium. Ga is considered critical element for the EU. To ensure adequate supply of Ga for the future, secondary sources such as bauxite residue should be exploited with efficient extraction methods. Therefore, in this study, mineral acids (H2SO4, HCl, and HNO3) and an organic acid (H2C2O4—oxalic acid), were evaluated for their efficiencies to extract Ga from bauxite residue. Using H2C2O4, the highest Ga leaching efficiencies were achieved, compared to other acids. The achieved leaching experimental results were considered for the construction of a design of experiment (DOE) model to achieve optimal conditions for Ga extraction using H2C2O4. These values were validated by experiments which resulted in ~ 94% accuracy. In the second part of the study, using pure Ga solution, the adsorption of Ga onto zeolite HY was studied. The effects of adsorbent dosage, temperature, and contact time on the adsorption of Ga from solution by zeolite HY were studied. The obtained adsorption experimental results were used to construct a DOE model to achieve optimal conditions for Ga adsorption on to zeolite HY. The DOE-achieved optimal conditions were evaluated by experiments in pure Ga solution, which resulted in an efficiency of ~ 99.4 %. In the third stage, the bauxite residue was leached in H2C2O4 under the optimal DOE conditions which resulted in 71% efficiency; thus the resulting bauxite residue solution was subjected to adsorption using zeolite HY under the optimal DOE conditions achieved. The Ga adsorption onto the zeolite was only 16% compared to the Ga adsorption of 99.4 % under the pure Ga solution, thus, representing the influences of the other leachates in the solution, which are minimizing the Ga adsorption onto the zeolite HY and providing an opportunity for future studies on the different mechanisms involved.

A novel step-wise indirect bioleaching using biogenic ferric agent for enhancement recovery of valuable metals from waste light emitting diode (WLED).

Waste light-emitting diodes (WLED) are of major interest as they are a considered secondary source of valuable metals with a high potential for polluting the environment. To recover the valuable metals from WLEDs, various methods have been applied such as direct and indirect bioleaching. A novel step-wise indirect bioleaching process has been developed in this study for recycling valuable metals from WLEDs using adapted Acidithiobacillus ferrooxidans. The ferric ion concentration was controlled at 4-5 g/L with step-wise addition of biogenic ferric for faster bioleaching rate. The results indicated the negative effect of bacterial attachment in bioleaching of WLEDs. A direct bioleaching offers low copper, nickel, and gallium leach yields, while all metals' recovery improved with step-wise indirect bioleaching. At a pulp density of 20 g/L, the copper, nickel, and gallium recovery efficiency was 83%, 97%, 84%, respectively. In addition, leaching time was reduced to 15 days from 30 days. From a technological perspective, the study proved that step-wise indirect bioleaching by biogenic ferric resulted in maximum valuable metal recovery from WLEDs at a low cost and via a short, simple and environmentally-friendly process.

Recovery of gallium from wafer fabrication industry wastewaters by Desferrioxamine B and E using reversed-phase chromatography approach

Gallium (Ga) is a critical element in developing renewable energy generation and energy efficient systems. The supply of Ga is at risk and needed recycling technologies for its availability in future. This study demonstrated the recovery of Ga3+ from low gallium concentrated wafer fabrication industry wastewaters using the siderophores desferrioxamine B (DFOB) and desferrioxamine E (DFOE). The complexation of Ga3+ by DFOB and DFOE was through hydroxamate group as demonstrated by infrared spectroscopy, nuclear magnetic resonance and density functional theory calculations. The high selectivity of DFOB/E towards Ga3+ was observed due to the formation of highly stable complex. Indeed, due to the formation of such high stability complex, the DFOB and DFOE were able to successfully complex 100% Ga in the two different process water from wafer fabrication industry. For the recovery of the siderophores, a high rate of decomplexation of Ga (>90%) was achieved upon addition of 6 times excess of ethylenediaminetetraacetic acid (EDTA) at pH of 3.5. More than 95% of Ga-DFOB and Ga-DFOE complex were recovered with purity (% of Ga moles in comparison to total moles of metals) of 69.8 and 92.9%, respectively by application of a C18 reversed-phase chromatography column. This study, for the first time, demonstrated a technical solution to the recovery of Ga3+ from the low concentrated wastewater based on siderophores and reversed-phase chromatography. A German patent application had been filed for this technology.