SEPARATION AND PURIFICATION TECHNOLOGY
·
2017
·
IF 3.359
Lang Yang,Feifei Jia,Shaoxian Song
The recovery of gold cyanide complex Au(CN) 2 − from gold cyanidation with graphene oxide (GO) and GO hydrogel have been studied to explore the possibility of the application of GO or GO hydrogel in gold cyanidation process for extracting gold. The study was performed on the adsorption of artificial Au(CN) 2 − aqueous solution on GO and GO hydrogel. The adsorption results, as well as the SEM-EDS, AFM and XPS, demonstrated that GO was a better adsorbent for the recovery of Au(CN) 2 − from aqueous solution than conventional activated carbon because of its higher adsorption capacity and adsorption rate. It has been also found that the adsorption of Au(CN) 2 − on GO followed the Langmuir isotherm and fitted well with both the pseudo-first-order and pseudo-second-order kinetics models. The recovery of Au(CN) 2 − with GO might be attributed to the interaction between Au(CN) 2 − and oxygenous function groups on GO surface. GO hydrogel exhibited excellent Au(CN) 2 − adsorption property and easy separation, which enabled it a potential adsorbent in gold cyanidation.
研究领域:
化学工程
·
材料科学
✓ 已验证
DOI
高影响因子
MINERALS ENGINEERING
·
2024
·
IF 4.9
Weilun Qian,Huibin Zhang,Jiankang Tan,Wenyu Feng,Huazhen Cao,Guoqu Zheng
The transformation of pyrite into ferrous sulfide (FeS) has a substantial significance in gold extraction from gold-bearing pyrite. This work proposed to treat pyrite by reactive diffusion with added elemental Fe for generating FeS. The diffusion kinetics and transformation mechanism during reactive synthesis were investigated via constructing Fe-FeS 2 powder diffusion couples. The results indicated that the formation of the pyrrhotite phase (Fe 1-x S, x = 0–0.5) firstly occurred at the interface of the diffusion couple. The interdiffusion coefficient ranged from 10 −16 m 2 s −1 ∼ 10 −12 m 2 s −1 at 723–873 K and the apparent activation energy of the product layer was about 147.59 kJ mol −1 . XRD and HRTEM results demonstrated that with the increase of sintering temperature, the diffusion of Fe played the pivotal role in the phase transformation of Fe 1-x S to FeS. Furthermore, the conversion rate of FeS can reach 95.82 % by optimizing sintering process. The synthesized FeS can be readily dissolved by sulfuric acid and the mass ratio of leaching residue is only 2.3 %, indicating that the precious metals in pyrite such as gold can be concentrated by nearly 43.5 times. This proposed method with the green economy characteristic would be a promising candidate for the pretreatment of gold-bearing pyrite.
研究领域:
化学工程
·
材料科学
·
冶金工程
✓ 已验证
产品关联
DOI
高影响因子
Journal of Environmental Chemical Engineering
·
2025
·
IF 7.2
Chao Luo,Enpei Zhu,Shengxuan Zhao,Shixing Wang,Hongying Xia,Jing Li,Linqing Dai,Gengwei Zhang,Likang Fu,Yonggang Zuo,Libo Zhang
Granular activated carbon (GAC) with large adsorptive capacity and high mechanical strength is the highly favored adsorbent for gold extraction. Once adsorption reaching saturation after prolong used, however, GAC usually needs periodic regeneration, which suffers from energy-intensity, low efficiency, serious carbon loss, and structure degradation. A novel approach for the ultrafast regeneration of spent activated carbon (SAC) after gold extraction is presented through combination of high temperature shock (HTS) and ultrasonic pickling (UP) treatment. This ultrafast regeneration is realized via a well-designed two-step method, in which the transient thermal treatment caused by HTS and chemical cleaning enhanced by ultrasound greatly shorten process duration to improve efficiency, suppress carbon loss and maintain carbon strength. As a result, SAC was regenerated to activated carbon (RAC) only in 150 s with an iodine adsorption value of ∼960.8 mg/g and average crushing strength of ∼43.51 N, respectively, significantly superior to the conventional methods. In addition, damaged fine-grained carbon after regeneration were also repurposed to prepare MoS 2 @AC composites for adsorbing organics (e.g. methylene blue dye), thereby achieving a sustainable application. This work not only provides a solution to the efficient regeneration of SAC, but also facilitate the sustainable recycle application of waste carbon materials.
研究领域:
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
ACS Sustainable Chemistry & Engineering
·
2023
·
IF 8.4
Xiaoxia Liu,Yangyang Wang,Ronghao Liu,Ping Lv,Wenfeng Xue,Jinxin Guo,Huiying Wei,Yanzhao Yang
With environmental problems and a shortage of resources, it is urgent to recover gold from electronic waste (e-waste). Meanwhile, it is necessary to explore the relationships between the structures and extraction performances of ionic liquids (ILs) to further improve the extraction capacities of ILs for gold. Herein, three pyrrolidinium-based ILs with various N-substituents were synthesized for solvent-free extraction of Au(III). The three pyrrolidinium-based ILs exhibited ultrahigh extraction capacities for Au(III) with the order of [Pyr-EA][NTf2] (524.6 mg·g–1) > [Pyr-Bu][NTf2] (457.3 mg·g–1) > [Pyr-C2OC2][NTf2] (403.5 mg·g–1). The effects of N-substituents on extraction performances were quantitatively investigated by electrostatic potential (ESP) and quantitative NMR. Among them, the ester group (−COOR) is the most beneficial to the extraction process, which is associated with an increased ESP value and boosted hydrophobicity. Notably, [Pyr-EA][NTf2] displayed outstanding selectivity in multimetal solutions; especially, it could selectively and efficiently extract Au(III) from the actual CPU. Furthermore, [Pyr-EA][NTf2] possesses significant reuseability and can maintain superior extraction efficiency of 84.3% after five cycles. These excellent performances together with low cost ($0.44·g–1 [Pyr-EA][NTf2]) and considerable profit ($29.72·g–1 [Pyr-EA][NTf2]) confirmed that [Pyr-EA][NTf2] is a promising prospect for sustainable recovery of gold from e-waste.
研究领域:
环境科学
·
材料化学
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2025
·
IF 13.2
Yasir Abbas,Sajjad Ali,Majid Basharat,H.M. Adeel Sharif,Muhammad Ahsan Iqbal,Mohamed Bououdina,Haoliang Wang,Niaz Ali Khan
The sustainable recovery of gold from electronic waste (E-waste) remains a significant challenge due to lack of multiple redox active-sites in the existing adsorbents, their high cost, and poor stability in extreme acidic conditions. Herein, we rationally designed the skeleton engineering of poly(organo)phosphazene via substitution reaction of hexachlorocyclotriphosphazene (HCCP) with p-phenylenediamine (DA), 1,4-benzenedithiol (DT), and 4-aminothiophenol (AT), producing poly(p-phenylenediamine-co-cylotriphosphazene) (PDA) with N-redox active-sites, poly(1,4-benzenedithiol-co-cylotriphosphazene) (PDT) containing S-redox active-sites, and poly(4-aminothiophenol-co-cylotriphosphazene) (PAT) holding dual N-S-redox active-sites. The PDA, PDT, and PAT in the N-bromosuccinimide/pyridine (NBS/Py) leaching solution demonstrated extraction efficiency of 83.7 % Au 3+ , 45.5 % Cu 2+, 44 % Ni 2+ , and 83.6 % Au 3+ , 47.4 % Cu 2+ , 48 % Ni 2+ , and 83.1 % Au 3+ , 48.5 % Cu 2+ , 48.8 % Ni 2+ . While, in the aqua regia, these adsorbents showed extraction efficiency of 70.0 % Au 3+ , 14.0 % Cu 2+ , 13.8 % Ni 2+ , and 92.3 % Au 3+ , 6.4 % Cu 2+ , 9.8 % Ni 2+ , and 95.6 % Au 3+ , 13.0 % Cu 2+ , 10.3 % Ni 2+ . In particular, the PAT with the dual N-S-redox active sites achieved maximal Au 3+ extraction efficiency (99.2 %), which is 1.05 and 1.04 times higher than PDA and PDT within 15 min, superb uptakes of 2000 mg/g, excellent selectivity (99.9 %) in a mixture of eight metal ions (Al, Co, Cu, K, Mg, Na, Ni, Mn), 100 % removal capacity and high stability even in pure aqua regia leaching solution. Gold ions adsorbed on these adsorbents, spontaneously reduced, experienced nucleation, and grew into single crystalline nanoplates along (111) planes as well as nanolayers composed of Au-single-atoms and Au-nanoclusters. The density function theory (DFT) calculations and variation in binding energies of N and S indicated that due to the synergy of dual N-S-redox active-sites, the PAT showed enhanced performances and excellent selectivity. For commercial applications, the as-synthesized PDA, PDT, and PAT were highly stable in pure aqua regia leaching solution, showing precisely selective and rapid gold extraction (70 %, 92 %, 96 %, respectively) than N- NBS/Py leaching systems (83 %) with traces of other competing metals. This study proves that skeleton-modulated poly(organo)phosphazene greatly facilitates gold extraction for industrial-scale applications.
研究领域:
材料科学
·
环境科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
RARE METALS
·
2020
·Vol. 40
·期 7
·1987-1994
·
IF 2.161
Wang Ya-Ting,Liu Men,Tang Nian,Li Sheng-Jian,Sun Yan,Wang Shi-Xiong,Yang Xiang-Jun
Abstract Solvent extraction based on ionic liquids is generally considered to be an environmentally benign and effective technology for gold(I) recovery. The aim of this work is to study gold(I) extraction from aurocyanide solution using fluorine-free ionic liquids [A336][SCN], [A336][MTBA] and [A336][Mal]. Various factors that affect gold(I) extraction (including concentration of ionic liquids, equilibrium pH, concentration of the modifier tributyl phosphate (TBP), reaction time and initial concentration of gold in an aqueous solution) were studied and optimized. The results indicate that the three Aliquat 336-based ionic liquids all exhibit excellent behaviors for gold(I) extraction. More than 99.8% of gold(I) can be extracted from the aqueous phase into the ionic liquid phase. The gold-loaded ionic liquids were characterized using infrared spectroscopy and mass spectrometry to study the extraction mechanism of gold(I). The results revealed that extraction of gold(I) into the ionic liquid phase was based on an exchange reaction between the anion Au(CN)
− 2
in aqueous solution and the anion SCN − in ionic liquid [A336][SCN]. The logarithmic relationship between distribution coefficient and TBP concentration indicates that two TBP molecules are involved in the formation of the extracted complex. The extracted complex was determined to be A336 + ·Au(CN)
− 2
·2TBP. In addition, the gold(I)-loaded ionic liquids can be efficiently stripped using NH 4 SCN, 2-methylthiobenzoic acid and methyl maltol. The results establish that Aliquat 336-based ionic liquids have potential application prospects in gold(I) recovery from cyanide solutions.
研究领域:
化学工程
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
NEW JOURNAL OF CHEMISTRY
·
2017
·Vol. 41
·期 14
·6180-6186
·
IF 3.269
Zeyang Xiang,Yan Zheng,Hong Zhang,Yan Yan,Xiaoyu Yang,Xia Xin,Yanzhao Yang
Microemulsions consisting of ionic liquid-type imidazolium gemini surfactants with different spacer lengths ([C14-n-C14im]Br2, n = 2, 4, 6), cyclohexane, n-hexyl alcohol and hydrochloric acid solution, were investigated for Au(III) extraction. [C14-n-C14im]Br2 in the microemulsion played a dual role as surfactant and extractant. The extraction efficiency (E%) of the [C14-n-C14im]Br2/cyclohexane/n-hexyl alcohol/HCl microemulsion system for Au was above 99% under optimal conditions. The results of our study indicated that the Au(III) extraction ability of the three different [C14-n-C14im]Br2 with different spacer lengths was better with longer a spacer. The mechanism for the Au(III) extraction by [C14-n-C14im]Br2 was confirmed to be based on an anion-exchange process by the continuous variation method and spectroscopic analysis (UV-Vis, FT-IR, 1H-NMR). The FT-IR spectra indicated that the better extraction ability of [C14-n-C14im]Br2 for Au(III) was positively correlated with the spacer length, due to a less significant steric effect of the methylene groups in surfactants with longer spacers. The electric conductivity values of the [C14-n-C14im]Br2 microemulsions indicated that surfactants with longer spacers can ionize to a higher extent to give more [C14-n-C14im]2+ cations and Br− anions, thus promoting anion-exchange and further increasing E%.
研究领域:
化学工程
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2021
·
IF 7.312
Ping Lv,Ronghao Liu,Yangyang Wang,Xiaoxia Liu,Yang Wu,Wenfeng Xue,Yanzhao Yang
In this study, a novel gemini-type benzimidazole ionic liquid [C 6 BIM 2 ][NTf 2 ] 2 was synthesized for efficient extract gold(III) from hydrochloric acid medium. Firstly, a series of parameters (e.g., vibrating time, the extractant concentration, acidity and salinity) were optimized and obtained the optimal extraction condition. Under this condition, the extraction efficiency can reach 98.42%, along with the distribution ratio of 186.87. Through the response surface methodology (RSM) model optimization, the amount of [C 6 BIM 2 ][NTf 2 ] 2 corresponding to different HCl concentration was determined for gold(III) extraction during actual operation. Then, verified the anion exchange mechanism with the aid of Job’s method, UV–vis, FT-IR and 13 C NMR. Thermodynamic parameters were calculated and implied that the extraction reaction was an exothermic and spontaneous process. Furthermore, organic phase loaded with gold(III) was easy to be completely stripped by CS(NH 2 ) 2 / HCl solution and its extraction ability was kept constant after 5 cycles extraction experiments. Meanwhile, [C 6 BIM 2 ][NTf 2 ] 2 has a superb ability to select gold(III) in the multi-metal solution. In general, [C 6 BIM 2 ][NTf 2 ] 2 showed distinguished selectivity and extraction ability for gold(III) from secondary resources, which was claimed to be a promising new style extractant.
研究领域:
化学工程
·
材料科学
✓ 已验证
DOI
高影响因子
Heliyon
·
2022
·
IF 3.776
Xiang Liu,Yongliang Wang,Li Xiao,Licheng Ma,Peiwei Han,Shufeng Ye
Gold is a valued, critical element whose chemical activation or extraction is challenging. Non-cyanide extraction of gold is now the focus, and N-bromosuccinimide(NBS) is attracting attention. Herein, new insights into the possible mechanism are deeply revealed through comprehensive analysis and detection of the reaction by using elementary gold and gold bearing ore. Experiments on gold foil indicate that Au can be activated in NBS solution to perform a satisfactory dissolution. Application of NBS in gold extraction from ore show a high yield of 86.24% under optimal conditions of NBS dosage 0.05 M, liquid-solid ratio 4:1, stirring speed 400 rpm, pH 8, 25 °C and leaching for 20 h, while yields of other coexisting metals are nearly negligible. The process leads to direct, efficient, one-pot conversion of gold, into simple water-soluble salts. Characterizations show that the framework of NBS are not destroyed, only bromine separates from the framework. The oxidation of neutral gold atom to trivalent Au (III) occurs in a mild, clean and room-temperature chemistry, which converts gold to [AuBr 4 ] - , and the framework to succinimide. The active bromine and radical Br (Br•) generated from in-situ autocatalysis of NBS are responsible for this. The systematic results herald a green procedure for preparation of gold derivatives and gold extraction industry.
研究领域:
化学工程
·
环境科学
✓ 已验证
DOI
PubMed
高影响因子
SCIENCE OF THE TOTAL ENVIRONMENT
·
2024
·
IF 8.2
Yu Qiang,Siyan Gao,Mengjiao Wu,Xiaoling Lei,Haiping Fang
Traditional mining practices not only cause severe environmental issues , but also face the problem of insufficient production capacity of gold to meet its growing demand. The proposed alternative strategies for gold production, such as the extraction of gold from seawater , still keep a formidable challenge due to their strong dependence on adsorbent materials with high capacity, selectivity , and sensitivity, while also needing to meet the demands of being environmentally friendly and cost-effective. In practice, the direct extraction of gold from seawater is limited by its extremely low yield and high energy expenditure. However, if the combination of gold extraction techniques with seawater desalination can substantially reduce the energy consumption, the extraction of gold from seawater will become economical and feasible. In this paper, we evaluate the feasibility of marine gold extraction using reduced graphene oxide membranes (rGOM) during the seawater desalination process . The rGOM can adsorb almost all Au 3+ from the solutions with trace concentrations of Au 3+ ranging from 10 ppb to 200 ppb. The adsorption quantity is linearly related to the concentration, indicating that the adsorption capacity of rGOM is much higher than the total amount of Au 3+ in the solution. Additionally, the rGOM can selectively adsorb 99 % of Au 3+ in the mixed solution while hardly adsorbing other common elements in seawater. More importantly, the rGOM exhibits the long-term stability over 30 days when being immersed in the solution, making it directly compatible with the existing seawater desalination processes. These specific properties allow the rGOM to be an ideal candidate for combining the extraction of gold from seawater with seawater desalination processes. Our findings provide a methodology for enhancing the economic efficiency of the extraction of gold from seawater and hold promise for addressing the problem of gold scarcity.
研究领域:
环境科学
·
材料科学
·
海洋学
✓ 已验证
DOI
PubMed
高影响因子
BRAZILIAN JOURNAL OF CHEMICAL ENGINEERING
·
2023
·Vol. 41
·期 1
·325-337
·
IF 1.2
Li Juan,Chen Shuliang,Chen Yunlong,Hu Xianzhi,Zi Futing
The thiosulfate method is a cyanide-free hydrometallurgical method for gold extraction, but the existence of copper ion in Cu 2+ –NH 3 –S 2 O 3 2− system is not conducive to the subsequent gold(I) recovery. This paper describes a process for improving the gold(I) adsorption capacity of mercapto-functionalized silica gel (MP-SG) by using ethylenediamine (en) as an additive to mask copper(II). The effects of en/Cu 2+ molar ratio, contact time, and pH on adsorption were investigated. The results showed that the addition of en increased the adsorption capacity of MP-SG to gold by more than 70%. X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) confirmed that the valence states of gold and copper on the adsorbent were both + 1, which confirmed the occurrence of competitive copper(II) adsorption. This could be inhibited by the addition of en without affecting the interfacial properties of MP-SG. UV–vis spectroscopy and the distribution of copper species revealed that addition of en changed the composition of the solution, forming a more stable Cu(en) 2 2+ complex, the fraction of Cu(en) 2 2+ increased with en content, thus reducing the competitive adsorption of Cu(II) to gold (I). The recovery rate of gold in the actual thiosulfate leaching solution was up to 92.35%, and en has almost no influence on the recycling process of the recovered leaching liquor, which proves the feasibility of this method in practical application.
研究领域:
湿法冶金
·
吸附技术
·
环境化学
·
材料科学
✓ 已验证
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2023
·
IF 8.6
Yong Xiang,Chang-Yuan Cheng,Meng-Hao Liu,Wen-Cai Bai,Zhou-Xuan Zang,Li Xu,Yi Yu,Guo-Ji Liu
The design of an efficient adsorbent for Au(III) has remained a challenging research focus, as the adsorbent needs to overcome competition from other ions while simultaneously addressing pore blockage caused by the reduction of Au(III) to elemental gold. In this study, we report the synthesis of a hierarchically porous metal–organic frameworks (MOFs) with ultra-large pores (300 nm) using the “MOF in MOF” method. This material facilitates enhanced adsorption kinetics by increasing the rate of gold ion adsorption and effectively prevents pore blockage resulting from Au(III) reduction, enabling access to the majority of adsorption sites. Batch experiments were conducted, and various complex water mixtures, including freshwater, simulated electronic waste solution, and gold ore leachate, were tested to demonstrate the rapid extraction of trace amounts of gold by the developed adsorbent. Remarkably, without additional functionalization, the adsorbent solely based on its pore advantage achieved a gold adsorption capacity of 1184 mg/g and reached 80 % adsorption within just 5 min (C0 = 100 mg/L, V/m = 2 L/g). Furthermore, the gold recovered from the leachate of gold ore exhibited a purity of 23.8 K (99.2 % purity).
研究领域:
材料科学
·
环境工程
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）