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Ran X, Yuan J. Study on the Deashing of Lignite with Hydrochloric Acid/Sodium Fluoride Leaching, Assisted by Microwave and Ultrasonic Waves. MATERIALS (BASEL, SWITZERLAND) 2024; 17:3537. [PMID: 39063829 PMCID: PMC11279183 DOI: 10.3390/ma17143537] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2024] [Revised: 07/12/2024] [Accepted: 07/15/2024] [Indexed: 07/28/2024]
Abstract
This study was aimed at investigating the effects of adding sodium fluoride (NaF) and using the assistance of ultrasonic and microwave energy on the removal efficiency of ash content during the hydrochloric acid (HCl) chemical leaching process of lignite samples from Zhaotong, Yunnan, China. Chemical leaching was conducted on lignite samples from Zhaotong, Yunnan, China, under the experimental conditions of time (30-120 min), temperature (55-95 °C), microwave power (240-800 W), ultrasonic power (25-100%), and NaF addition concentration (0.2-1.2 M). The addition of NaF greatly improved the removal efficiency of ash content from lignite. Under optimized conditions, the addition of NaF increased the removal rate of ash content from lignite from 25% to 65.27%. The microwave-assisted deashing of lignite can significantly improve the deashing efficiency, with positive implications for the microstructure regulations of lignite. Ultrasonic-assisted deashing can lower the temperature for coal powder burnout and enhance the combustion performance of coal.
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Affiliation(s)
- Xinming Ran
- College of Environmental and Chemical Engineering, Dalian University, Dalian 116622, China;
| | - Jie Yuan
- School of Chemistry and Materials Engineering, Liupanshui Normal University, Liupanshui 553004, China
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Huo Q, Li R, Chen M, Zhou R, Li B, Chen C, Liu X, Xiao Z, Qin G, Huang J, Long T. Mechanism for leaching of fluoride ions from carbon dross generated in high-temperature and low-lithium aluminum electrolytic systems. JOURNAL OF HAZARDOUS MATERIALS 2024; 469:133838. [PMID: 38430589 DOI: 10.1016/j.jhazmat.2024.133838] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2023] [Revised: 02/05/2024] [Accepted: 02/18/2024] [Indexed: 03/05/2024]
Abstract
Carbon dross, a hazardous solid waste generated during aluminum electrolysis, contains large amounts of soluble fluoride ions for the main components of the electrolyte (such as Na3AlF6 and NaF). Response surface methodology (RSM) was used to investigate the mechanism for fluoride ion leaching from carbon dross via water leaching, acid leaching and alkali leaching, and the kinetic and thermodynamic principles of the leaching process were revealed. The RSM predicted the optimum conditions of water leaching, alkali leaching and acid leaching, and the conditions are as follows: temperature, 50 °C; shaking speed, 213 r·min-1; particle size, 0.075 mm; shaking speed, 194 r·min-1; liquid-solid ratio, 12.6 mg·L-1; sodium hydroxide concentration, 1.53 mol·L-1; liquid-solid ratio, 25.0 mg·L-1; sulfuric acid concentration, 2.00 mol·L-1; and temperature, 60 °C,and actual results which were almost consistent with the predicted results were gained. The fluoride ions in the alkaline and acid leaching solutions were mainly the dissociation products of fluorides such as Na3AlF6, Na5Al3F14 and CaF2, as indicated by thermodynamics calculations. In particular, the fluoride compounds dissolved in alkali solution were Na3AlF6, Na5Al3F14, AlF3, ZrF4, K3AlF6, while the acid solution could dissolve only Na3AlF6 and CaF2. The leaching kinetics experiments showed that the leaching rate fit the unreacted shrinking core model [1-2/3α-(1-α)2/3 =kt] and that the leaching process was controlled by internal diffusion. This study provides theoretical guidance for the removal of soluble fluoride ions from carbon dross and will also assist in the separation of electrolytes from carbon dross. ENVIRONMENTAL IMPLICATION: Carbon dross, a hazardous waste generated during the aluminum electrolysis production process, contains a large amount of soluble fluoride. Improper storage will lead the fluoride ions pollution in soil, surface water or groundwater under the direct contact between carbon dross and rainfall, snow or surface runoff. The influence of wind will cause carbon dross dust to pollute further areas. With the human body long-term contact with fluoride ion contaminated soil or water, human health will be seriously harmed.
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Affiliation(s)
- Qiang Huo
- Key Laboratory of Ecology of Rare and Endangered Species and Environmental Protection (Guangxi Normal University), Ministry of Education - Guangxi Key Laboratory of Landscape Resources Conservation and Sustainable Utilisation in Lijiang River Basin, Guilin, Guangxi 541006, China; Guangxi Key Laboratory of Environmental Processes and Remediation in Ecologically Fragile Regions, Guilin, Guangxi 541006, China; College of Environment and Resources, Guangxi Normal University, Guilin, Guangxi 541006, China
| | - Ruoyang Li
- Guangxi Key Laboratory of Environmental Processes and Remediation in Ecologically Fragile Regions, Guilin, Guangxi 541006, China; College of Environment and Resources, Guangxi Normal University, Guilin, Guangxi 541006, China
| | - Mingyan Chen
- Guangxi Key Laboratory of Environmental Processes and Remediation in Ecologically Fragile Regions, Guilin, Guangxi 541006, China; College of Environment and Resources, Guangxi Normal University, Guilin, Guangxi 541006, China
| | - Runyou Zhou
- College of Environment and Resources, Guangxi Normal University, Guilin, Guangxi 541006, China
| | - Bin Li
- College of Environment and Resources, Guangxi Normal University, Guilin, Guangxi 541006, China
| | - Chunqiang Chen
- College of Environment and Resources, Guangxi Normal University, Guilin, Guangxi 541006, China
| | - Xi Liu
- Key Laboratory of Ecology of Rare and Endangered Species and Environmental Protection (Guangxi Normal University), Ministry of Education - Guangxi Key Laboratory of Landscape Resources Conservation and Sustainable Utilisation in Lijiang River Basin, Guilin, Guangxi 541006, China; School of Economics and Management, Guangxi Normal University, Guilin 541006, China
| | - Zeqi Xiao
- College of Environment and Resources, Guangxi Normal University, Guilin, Guangxi 541006, China
| | - Guozhao Qin
- College of Environment and Resources, Guangxi Normal University, Guilin, Guangxi 541006, China
| | - Jianghui Huang
- College of Environment and Resources, Guangxi Normal University, Guilin, Guangxi 541006, China
| | - Tengfa Long
- Key Laboratory of Ecology of Rare and Endangered Species and Environmental Protection (Guangxi Normal University), Ministry of Education - Guangxi Key Laboratory of Landscape Resources Conservation and Sustainable Utilisation in Lijiang River Basin, Guilin, Guangxi 541006, China; Guangxi Key Laboratory of Environmental Processes and Remediation in Ecologically Fragile Regions, Guilin, Guangxi 541006, China; College of Environment and Resources, Guangxi Normal University, Guilin, Guangxi 541006, China.
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Xu Z, Xu L, Wei Q, Shen S, Liu J, Zhu Y. Microwave hydrothermal sulfuric acid leaching of spent cathode carbon from aluminum electrolysis for high efficiency removal of insoluble calcium fluoride. WASTE MANAGEMENT (NEW YORK, N.Y.) 2024; 179:110-119. [PMID: 38471249 DOI: 10.1016/j.wasman.2024.03.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Revised: 02/21/2024] [Accepted: 03/05/2024] [Indexed: 03/14/2024]
Abstract
Toxic substances, like fluoride salts present in spent cathode carbon (SCC), have been a great risk to the environment and public health. Our approach involves alkali leaching to eliminate soluble fluoride, followed by microwave hydrothermal acid leaching to efficiently remove insoluble CaF2 from SCC. The optimized conditions, including a temperature of 353 K, a solid-liquid ratio of 1:20, and a 60-minute reaction time, resulted in an impressive 95.6 % removal of fluoride from SCC. Various characterization techniques were employed to analyze the composition, micro-morphology, and elemental content of the materials before and after the leaching process. Furthermore, critical process parameters on the leaching separation of insoluble CaF2 during microwave hydrothermal acid leaching were systematically investigated. The study removal mechanism revealed the transformation of insoluble CaF2 in the process of microwave oxidation insertion-hydrothermal acid leaching for SCC. The kinetic characteristics of the two-stage leaching process of CaF2 at different temperatures were analyzed according to the shrinkage kernel model. The results indicate that the two-stage leaching process of CaF2 is affected by mixing control and by diffusion control, severally. The expansion of the graphite flake layer of SCC through oxidative intercalation was identified as a critical process for the thorough removal of CaF2. Microwave hydrothermal acid leaching demonstrated a 17 % improvement over traditional hydrothermal acid leaching within the same reaction time, showcasing a noteworthy enhancement in fluoride removal. Consequently, the microwave oxidizing intercalation-hydrothermal acid leaching treatment of SCC, as explored in this study, offers an effective approach for achieving deep defluoridation of SCC.
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Affiliation(s)
- Zhangbiao Xu
- Faculty of Metallurgical and Energy Engineering, National Local Joint Laboratory of Engineering Application of Microwave Energy and Equipment Technology, Kunming University of Science and Technology, Kunming 650093, PR China
| | - Lei Xu
- Faculty of Metallurgical and Energy Engineering, National Local Joint Laboratory of Engineering Application of Microwave Energy and Equipment Technology, Kunming University of Science and Technology, Kunming 650093, PR China; State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization, Kunming University of Science and Technology, Kunming 650093, PR China.
| | - Qun Wei
- Faculty of Metallurgical and Energy Engineering, National Local Joint Laboratory of Engineering Application of Microwave Energy and Equipment Technology, Kunming University of Science and Technology, Kunming 650093, PR China; State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization, Kunming University of Science and Technology, Kunming 650093, PR China
| | - Shifu Shen
- BGRIMM Technology Group, Beijing 100160, PR China
| | - Jianhua Liu
- Faculty of Metallurgical and Energy Engineering, National Local Joint Laboratory of Engineering Application of Microwave Energy and Equipment Technology, Kunming University of Science and Technology, Kunming 650093, PR China; State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization, Kunming University of Science and Technology, Kunming 650093, PR China
| | - Yanli Zhu
- State Key Laboratory of Explosion Science and Technology, Beijing Institute of Technology, Beijing 100081, PR China
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Liu B, Duan L, Cai S, Ren Q, Li J, Wang Y, Zeng Y. A clean and efficient route for extraction of vanadium from vanadium slag by electro-oxidation combined with ultrasound cavitation. ULTRASONICS SONOCHEMISTRY 2024; 102:106735. [PMID: 38128390 PMCID: PMC10772816 DOI: 10.1016/j.ultsonch.2023.106735] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Revised: 12/07/2023] [Accepted: 12/15/2023] [Indexed: 12/23/2023]
Abstract
Extracting vanadium (V) from vanadium slag (VS) by the traditional roasting-leaching process has disadvantages of high energy consumption and high poisonous gases emission. In this work, a green and efficient route was developed to extract V from VS without roasting by electro-oxidation combined with ultrasound cavitation (EOUC) intensification in sulfuric acid solution. The leaching parameters (e.g., leaching temperature, sulfuric acid concentration, anodic current density, ultrasound power, liquid to solid ratio, leaching time and particle size) were optimized. The leaching mechanism was explored by comparing the leaching behavior and mineralogical evolution of the direct sulfuric acidic leaching (DSL), electro-oxidation-assisted sulfuric acidic leaching (EOSL), ultrasound cavitation-assisted sulfuric acidic leaching (UCSL) and EOUC methods. The results show that introducing electric field strengthens the ultrasound cavitation effect on slag particles in sulfuric acid solution. Under the optimum parameter of EOUC method, the leaching rate of V from VS is as high as 94.64 %. Using EOUC method can open the silicate-wrapped structure of the spinel, increase pore volume of VS from 0.00127 cm3 g-1 to 0.01124 cm3 g-1, decrease slag particle size from 26.8 μm to 16.4 μm and improve specific surface area from 0.508 m2 g-1 to 10.855 m2 g-1, which significantly accelerate V leaching process. The exposed spinel was oxidized by both electrochemical route and chemical route, forming a mixture of V3+ ion and VO2+ ion after leaching.
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5
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Wang C, Mao S. Study on the effect of an ultrasound assisted reaction on the crystallization properties of recovered cryolite. RSC Adv 2023; 13:35359-35368. [PMID: 38053682 PMCID: PMC10695192 DOI: 10.1039/d3ra06661d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2023] [Accepted: 11/29/2023] [Indexed: 12/07/2023] Open
Abstract
During the treatment of spent cathode carbon from electrolytic aluminum, a large amount of fluoride containing wastewater is generated. By adding different sodium source and aluminum source reagents, under the conditions of different addition order, pH, temperature and time, the effects of conventional static reaction, stirring reaction and ultrasonic assisted reaction on the crystallization properties of recovered cryolite were investigated. The results showed that under the optimum reaction conditions (sodium source: NaCl, aluminum source: AlCl3, the molar ratio of AlCl3 to NaCl is 1 : 3, addition order: first addition of AlCl3 and then NaCl, pH is 8.57, time is 40 min, temperature at room temperature), the removal efficiency of fluoride ions was the highest when ultrasound assisted treatment was used. The cryolite products with ultrasound assisted crystallization and without ultrasound assisted crystallization were characterized using SEM and TEM. The results showed that the crystal particles obtained by ultrasound assisted crystallization were relatively concentrated, and the morphology was regular and the surface was smooth. Design Expert orthogonal software was used to design the response surface test, it was found that ultrasound time has the most significant impact on the content of recovered cryolite among single factors, and the interaction between ultrasound frequency and ultrasound power, ultrasound power and ultrasound time was highly significant among multiple factors.
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Affiliation(s)
- Chenchen Wang
- Mining College, Guizhou University Guiyang 550025 China
- National & Local Joint Laboratory of Engineering for Effective Utilization of Regional Mineral Resources from Karst Areas Guiyang 550025 China
- Guizhou Key Laboratory of Comprehensive Utilization of Nonmetallic Mineral Resources Guiyang 550025 China
| | - Song Mao
- Mining College, Guizhou University Guiyang 550025 China
- National & Local Joint Laboratory of Engineering for Effective Utilization of Regional Mineral Resources from Karst Areas Guiyang 550025 China
- Guizhou Key Laboratory of Comprehensive Utilization of Nonmetallic Mineral Resources Guiyang 550025 China
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Li X, Liu Y, Zhang TA. A comprehensive review of aluminium electrolysis and the waste generated by it. WASTE MANAGEMENT & RESEARCH : THE JOURNAL OF THE INTERNATIONAL SOLID WASTES AND PUBLIC CLEANSING ASSOCIATION, ISWA 2023; 41:1498-1511. [PMID: 37052310 DOI: 10.1177/0734242x231164321] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
Aluminium is produced by electrolysis using alumina (Al2O3) as raw material and cryolite (Na3AlF6) as electrolyte. In this Hall-Héroult process, the energy consumption is relatively large, and solid wastes such as spent anodes and spent pot liner, flue gas and waste heat are generated. Therefore, this article discusses from the perspective of high energy consumption and high pollution and summarizes the methods to reduce energy consumption and solve pollution problems. The functions of carbon anode, carbon cathode, refractory material and sidewall in aluminium electrolysis cells are discussed in detail. The process of aluminium electrolysis and the ways to improve the current efficiency of aluminium electrolysis cells and reduce their energy consumption are outlined. The causes and treatment methods of spent anodes, spent cathodes, spent refractories and spent spot liner are reviewed. The research progress of waste heat recovery and aluminium electrolysis flue gas purification are analysed. And the future research directions of aluminium electrolysis flue gas are provided.
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Affiliation(s)
- Xueke Li
- Key Laboratory of Ecological Metallurgy of Multi-metal Intergrown Ores of Ministry of Education, School of Metallurgy, Northeastern University, Shenyang, Liaoning, China
| | - Yan Liu
- Key Laboratory of Ecological Metallurgy of Multi-metal Intergrown Ores of Ministry of Education, School of Metallurgy, Northeastern University, Shenyang, Liaoning, China
| | - Ting-An Zhang
- Key Laboratory of Ecological Metallurgy of Multi-metal Intergrown Ores of Ministry of Education, School of Metallurgy, Northeastern University, Shenyang, Liaoning, China
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Wang C, Mao S, Li L. Study on ultrasonic leaching and recovery of fluoride from spent cathode carbon of aluminum electrolysis. RSC Adv 2023; 13:16300-16310. [PMID: 37266505 PMCID: PMC10230273 DOI: 10.1039/d3ra02088f] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Accepted: 05/22/2023] [Indexed: 06/03/2023] Open
Abstract
Under the assistance of ultrasound, the fluoride in the spent cathode carbon of aluminum electrolysis was recovered by the process of washing first and then leaching. The effects of time, temperature, liquid-solid ratio, ultrasonic power, alkali amount and acid concentration on the leaching rate of fluoride were investigated. The useful components in the leaching solution were recovered by evaporation crystallization and cryolite regeneration. The tests of X-ray diffraction (XRD), X-ray fluorescence spectroscopy (XRF), and scanning electron microscopy combined with energy dispersive spectroscopy (SEM-EDS) showed that under the optimal experimental conditions (water washing: 50 s, 3 : 1, 420 W; alkaline leaching: alkali amount 1 g, 60 min, 70 °C, 7 : 1, 480 W; acid leaching: acid concentration 0.6 mol L-1, 60 min, 5 : 1, 70 °C, 480 W), the leaching rate of fluoride was 82.99%, and the fluoride contents recovered in the water washing and leaching processes are 94.67% and 95%, respectively. There is no solid waste and waste water in the whole experimental process.
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Affiliation(s)
- Chenchen Wang
- College of Mining, Guizhou University Guiyang 550025 China
- Guizhou Key Laboratory of Comprehensive Utilization of Non-metallic Mineral Resources Guiyang 550025 China
- National & Local Joint Laboratory of Engineering for Effective Utilization of Regional Mineral Resources from Karst Areas Guiyang 550025 China
| | - Song Mao
- College of Mining, Guizhou University Guiyang 550025 China
- Guizhou Key Laboratory of Comprehensive Utilization of Non-metallic Mineral Resources Guiyang 550025 China
- National & Local Joint Laboratory of Engineering for Effective Utilization of Regional Mineral Resources from Karst Areas Guiyang 550025 China
| | - Longjiang Li
- College of Mining, Guizhou University Guiyang 550025 China
- Guizhou Key Laboratory of Comprehensive Utilization of Non-metallic Mineral Resources Guiyang 550025 China
- National & Local Joint Laboratory of Engineering for Effective Utilization of Regional Mineral Resources from Karst Areas Guiyang 550025 China
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Nazerian M, Bahaloo-Horeh N, Mousavi SM. Enhanced bioleaching of valuable metals from spent lithium-ion batteries using ultrasonic treatment. KOREAN J CHEM ENG 2023. [DOI: 10.1007/s11814-022-1257-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
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Sang Y, Liu C, Yuan H, Chi Z, Ji L, Cao R, Gu Q. Fluoride-immobilized co-processing and resource utilization of aluminum-electrolyzed spent cathode carbon in brick-fired kiln. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2022; 29:87527-87533. [PMID: 35809169 DOI: 10.1007/s11356-022-21713-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Accepted: 06/24/2022] [Indexed: 06/15/2023]
Abstract
Spent cathode carbon (SCC) is hazardous waste from the electrolytic aluminum industry due to its high levels of soluble fluoride, while brick-fired kiln provides the clay and heating conditions needed to immobilize fluoride. However, SCC reusing is still understudied, meanwhile co-processing and resource utilization of SCC in brick-fired kiln were still not reported in the literatures in addition to a Chinese patent of the authors. Here, the effects of firing temperatures, firing time, clay doses and calcium doses on the fluoride-immobilized performance of SCC co-processing were explored in a simulated brick-firing kiln, and their mechanisms were analyzed by SEM and XRD. The results indicated that clay-added co-processing in brick-fired kiln was a preferred choice without required additional additives or operations. The leached fluoride met Chinese standards by clay-added co-processing at ≥ 800 °C/ ≥ 40 g clay/ ≥ 120 min. Clay and calcium-added co-processing in brick-fired kiln was another alternative choice with higher fluoride-immobilization rates. The leached fluoride met Chinese standard (GB5085.3-2007) by clay and calcium-added co-processing at ≥ 500 °C/ ≥ 30 min/ ≥ 5 g clay/ ≥ 0.5 g CaCO3. SEM and XRD indicated that SiO2 in clay reacted with sodium in SCC and formed vitreous analog (Na1.55Al1.55Si0.45O4) to prevent fluoride ion migration and the newly-formed k-Feldspar (K2O.Al2O3.6SiO2) may adsorb fluoride ions in clay-added co-processing. Soluble fluoride NaF in SCC were converted into water-insoluble cuspidine in clay and calcium-added co-processing, in addition to the crystalline phase conversion in clay-added co-processing. Therefore, the risks of finished bricks to human health and the environment were greatly reduced after clay-added or clay and calcium-added treatments.
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Affiliation(s)
- Yimin Sang
- Department of Environmental Engineering, Beijing Institute of Petrochemical Technology, Beijing, 102617, China
| | - Chang Liu
- Department of Environmental Engineering, Beijing Institute of Petrochemical Technology, Beijing, 102617, China
| | - Huicong Yuan
- Department of Environmental Engineering, Beijing Institute of Petrochemical Technology, Beijing, 102617, China
| | - Zhaoxu Chi
- Department of Environmental Engineering, Beijing Institute of Petrochemical Technology, Beijing, 102617, China
| | - Longjie Ji
- Beijing Construction Engineering Group Environmental Remediation Co. Ltd., Beijing, 100015, China
| | - Ruiqi Cao
- Department of Environmental Engineering, Beijing Institute of Petrochemical Technology, Beijing, 102617, China
| | - Qingbao Gu
- State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China.
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Sang Y, Liang Z, Li C, Lu T, Zhu L, Sun Y, Gu Q. Solidification/stabilization of spent cathode carbon from aluminum electrolysis by vitric, kaolin and calcification agent: fluorides immobilization and cyanides decomposition. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2022; 29:85537-85546. [PMID: 35799010 DOI: 10.1007/s11356-022-21803-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2022] [Accepted: 06/29/2022] [Indexed: 06/15/2023]
Abstract
Spent cathode carbon (SCC) is a hazardous waste containing fluorides and cyanides from aluminum electrolysis. Many literatures have focused on SCC leaching; however, SCC hazard-free treatment remains understudied. This article used 10.0 g raw SCC sample to explore the vitric/kaolin solidification and calcium stabilization of SCC, and analyze their hazard-free mechanisms by the methods of XRD and SEM. The leached fluorides were all below the Chinese identification standard for hazardous wastes (GB5085.3-2007), whether at 750/950 °C for 60 min above 8.0 g vitric, or at 1200 °C for 120 min with above 8.0 g kaolin, or above 700 °C for more than 30 min with above 0.5 g CaCO3. Kaolin/vitric solidification relied on the massive addition of vitric and kaolin to produce glassy or glass-like material (K2O·Al2O3·6SiO2) which may retain fluoride. Calcium stabilization converted soluble fluoride NaF in raw SCC sample into insoluble CaF2. Heating 60 min at 500-1200 °C at oxygen atmosphere decomposed almost of cyanides, with leached cyanides meeting Chinese standard GB5085.3-2007. Mass-loss rates of kaolin addition came from a large amount of adsorbed water and structural water in kaolinite and illite wai lost, and that of CaCO3/CaSO4 addition was attributed to their decomposition into volatile CO2/SO2, while that of CaO was a little negative due to its absorption of water vapor and CO2. In brief, as the effective hazard-free manner of SCC, both kaolin/vitric solidification and calcium stabilization successfully have achieved fluoride immobilization and cyanide decomposition.
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Affiliation(s)
- Yimin Sang
- Department of Environmental Engineering, Beijing Institute of Petrochemical Technology, Beijing, 102617, China
| | - Zengyin Liang
- Department of Environmental Engineering, Beijing Institute of Petrochemical Technology, Beijing, 102617, China
| | - Chenyang Li
- Department of Environmental Engineering, Beijing Institute of Petrochemical Technology, Beijing, 102617, China
| | - Taotao Lu
- Department of Environmental Engineering, Beijing Institute of Petrochemical Technology, Beijing, 102617, China
| | - Ling Zhu
- Department of Environmental Engineering, Beijing Institute of Petrochemical Technology, Beijing, 102617, China
| | - Yiming Sun
- State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China
| | - Qingbao Gu
- State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China.
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Chen Y, Li P, Bu X, Wang L, Liang X, Chehreh Chelgani S. In-depth purification of spent pot-lining by oxidation-expansion acid leaching – A comparative study. Sep Purif Technol 2022. [DOI: 10.1016/j.seppur.2022.122313] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Zhang L, Xiao J, Yao Z, Yuan J, Ye S, Zhong Q. Complementary advantages of spent pot lining and coal gangue in the detoxification and valuable components recovery process. CHEMOSPHERE 2022; 307:136064. [PMID: 35981622 DOI: 10.1016/j.chemosphere.2022.136064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Revised: 08/04/2022] [Accepted: 08/10/2022] [Indexed: 06/15/2023]
Abstract
As a hazardous solid waste rich in carbon and fluorine, spent pot lining (SPL) is a huge threat to sustainable production and environmental security. As abundant carbon and fluorine resources, the use of such valuable components has great practical and economic significance. Based on the environmental concerns and the component characteristics of SPL, coal gangue (CG), the largest output of solid wastes in the coal-producing industry and rich in aluminum and silicon, was introduced in the utilization and detoxification process of SPL in this work. The substance flow of the co-utilization process presents a circular economy and complementary advantages of SPL and CG. Pure regular fibrous silicon carbides were obtained owing to the synergy effect of SPL and CG. Aluminum from CG and SPL was utilized to prepare dawsonite combined with the sodium from the impurities removal process. Pure cryolite was obtained via mixing wastewater from the silicon carbide purification process and the dawsonite extraction process. Almost all components in SPL and CG were converted into valuable products, and no wastewater and residue was discharged. Thus, a sustainable process of trash to treasure and circular economy for treating CG and SPL was established here with environmental and economically friendly characteristics, which gave a new insight into utilizing wastes with complementary advantages.
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Affiliation(s)
- Liuyun Zhang
- School of Metallurgy and Environment, National Engineering Laboratory of Efficient Utilization of Refractory Nonferrous Metal Resources, Central South University, Changsha, 410083, PR China
| | - Jin Xiao
- School of Metallurgy and Environment, National Engineering Laboratory of Efficient Utilization of Refractory Nonferrous Metal Resources, Central South University, Changsha, 410083, PR China.
| | - Zhen Yao
- School of Materials and Architectural Engineering, Guizhou Normal University, Guiyang, 550001, PR China
| | - Jie Yuan
- School of Chemistry and Materials Engineering, Liupanshui Normal University, Liupanshui, 553004, PR China
| | - Shengchao Ye
- School of Metallurgy and Environment, National Engineering Laboratory of Efficient Utilization of Refractory Nonferrous Metal Resources, Central South University, Changsha, 410083, PR China
| | - Qifan Zhong
- School of Metallurgy and Environment, National Engineering Laboratory of Efficient Utilization of Refractory Nonferrous Metal Resources, Central South University, Changsha, 410083, PR China.
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Chen R, Chen Y, Liang X, Kong Y, Fan Y, Liu Q, Yang Z, Tang F, Muya J, Dessie Walle M, Wang L. Oxidative exfoliation of spent cathode carbon: a two-in-one strategy for its decontamination and high-valued application. Chin J Chem Eng 2022. [DOI: 10.1016/j.cjche.2022.10.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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15
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Yang K, Li J, Huang W, Zhu C, Tian Z, Zhu X, Fang Z. A closed-circuit cycle process for recovery of carbon and valuable components from spent carbon cathode by hydrothermal acid-leaching method. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2022; 318:115503. [PMID: 35752004 DOI: 10.1016/j.jenvman.2022.115503] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Revised: 05/16/2022] [Accepted: 06/07/2022] [Indexed: 06/15/2023]
Abstract
Spent carbon cathode (SCC) as a hazardous solid waste produced in aluminum electrolysis industry, contains plenty valuable components but generate a seriously threat to the environment. This paper focus on a closed-circuit cycle process for direct treatment of SCC based on the hydrothermal acid-leaching method. Thermodynamic calculation, single factor experiment, orthogonal experiment and kinetic study are utilized to obtain the leaching properties of impurities, optimize the leaching conditions, study the influence of conditions on leaching, and capture the restriction factors of leaching. The results indicate that the carbon content of the treated SCC can reach 97.3% when the leaching condition attach the optimal (liquid-solid ratio of 25 mL/g, temperature of 413 K, time of 270 min and acid concentration of 4 mol/L), and liquid-solid ratio is regarded as the crucial factor influencing on that. In addition, the activation energy of impurities reaches 6.25 kJ/mol and the whole leaching process is controlled by the diffusion extent. Finally, the filtrate after the hydrothermal acid leaching is treated, and calcium fluoride, cryolite and sodium chloride are successfully separated. The proposed process eliminates the harm of SCC to the environment, and completes a closed-circuit cycle for the treatment of SCC and recovery of valuable components. It enriches the hydrometallurgical processes of SCC, and provides an attractive scheme for the treatment of SCC.
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Affiliation(s)
- Kai Yang
- School of Metallurgical Engineering, Xi'an University of Architecture and Technology, Xi'an, 710055, Shaanxi, China
| | - Jie Li
- School of Metallurgical Engineering, Xi'an University of Architecture and Technology, Xi'an, 710055, Shaanxi, China
| | - Wenlong Huang
- School of Metallurgical Engineering, Xi'an University of Architecture and Technology, Xi'an, 710055, Shaanxi, China
| | - Chengping Zhu
- School of Metallurgical Engineering, Xi'an University of Architecture and Technology, Xi'an, 710055, Shaanxi, China
| | - Zhongliang Tian
- School of Metallurgy and Environment, Central South University, 410083, Changsha, China
| | - Xinye Zhu
- School of Metallurgical Engineering, Xi'an University of Architecture and Technology, Xi'an, 710055, Shaanxi, China
| | - Zhao Fang
- School of Metallurgical Engineering, Xi'an University of Architecture and Technology, Xi'an, 710055, Shaanxi, China.
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16
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Xiao Y, Li L, Huang M, Liu Y, Xu J, Xu Z, Lei Y. Treating waste with waste: Metals recovery from electroplating sludge using spent cathode carbon combustion dust and copper refining slag. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 838:156453. [PMID: 35660588 DOI: 10.1016/j.scitotenv.2022.156453] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Revised: 05/21/2022] [Accepted: 05/31/2022] [Indexed: 06/15/2023]
Abstract
Electroplating sludge is a hazardous waste and secondary metal resource because of its heavy metal content, which poses a huge threat to environmental safety if not properly disposed. An innovative process of oxidizing roasting followed by water leaching and smelting reduction to recover Cr, Cu, and Ni from electroplating sludge was proposed in this research, in which other two hazardous wastes of spent cathode carbon combustion dust and copper refining slag were co-treated. The NaF from spent cathode carbon combustion dust could convert Cr2O3 to Na2CrO4 using the oxidizing roasting process, resulting in a Cr recovery through the subsequent water leaching. The Na2CrO4 formation was promoted by CaO owing to it transferring the Cr spinel phase of FeCr2O4 [1+] to CaCrO4 and then to Na2CrO4. Under optimal conditions, the Cr recovery reached 97.1 %, and most 'F' was solidified into CaF2. In the next smelting reduction of the leaching residue, the Cu and Ni were recovered mainly in the form of Cu-Ni alloy. The addition of copper refining slag promoted their recovery, due to it modifying the molten slag and alloy structures and increasing the Cu-Ni alloy separation from molten slag. Some generated high-melting-point Cu-Ni-Fe and Ni-Fe alloys were converted to a Cu-Ni alloy with a low melting point in presence of Co from the copper refining slag, simultaneously with which the Fe was transferred out from Cu-Ni-Fe and Ni-Fe alloys and combined with Co to form a Fe-Co alloy. It increased Cu-Ni alloy droplets aggregation from molten slag and decreased their contents in the residual slag. Under optimized conditions, the Cu and Ni contents in the residual slag decreased to 0.37 and 0.06 wt%, respectively. Besides, the residual slag mainly composed of CaO, CaF2 and SiO2 could be used to prepare building materials rendering it harmless.
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Affiliation(s)
- Yang Xiao
- College of Environmental Science and Engineering, Donghua University, Shanghai 201620, PR China
| | - Lei Li
- College of Environmental Science and Engineering, Donghua University, Shanghai 201620, PR China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, PR China.
| | - Manhong Huang
- College of Environmental Science and Engineering, Donghua University, Shanghai 201620, PR China
| | - Yanbiao Liu
- College of Environmental Science and Engineering, Donghua University, Shanghai 201620, PR China
| | - Jingzhuang Xu
- College of Environmental Science and Engineering, Donghua University, Shanghai 201620, PR China
| | - Zhipeng Xu
- College of Environmental Science and Engineering, Donghua University, Shanghai 201620, PR China
| | - Yun Lei
- Faculty of Metallurgical and Energy Engineering, Kunming University of Science and Technology, Kunming 650093, PR China
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17
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Leaching Kinetics of Aluminum from Alkali-Fused Spent Cathode Carbon Using Hydrochloric Acid and Sodium Fluoride. Processes (Basel) 2022. [DOI: 10.3390/pr10050849] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Abundant carbon resides in spent cathode carbon (SCC) of aluminum electrolysis and its high-purity carbon powder is conducive to high-value recycling. The alkali-fused SCC was separated and effectively purified using an HCl/NaF solution. Effects of particle size, leaching temperature, time, initial acid concentration, and sodium fluoride dosage, on the purity of carbon powder and aluminum removal rate, were investigated. Using aluminum as the research object, kinetics of aluminum acid leaching were examined by single-factor experiments. Results showed that under an initial 4 M HCl concentration, particle size D(50) = 67.49 μm, liquid-solid ratio of 15:1, 333 K, 120 min, 0.3 M NaF, carbon powder with ash level below 1% were obtained in subsequent purification of SCC. The leaching process was described by Avram equation, the model characteristic parameter was 0.75147 and the apparent activation energy was 22.056 kJ/mol, which indicated a mixed control mechanism between chemical reactivity and diffusion. The kinetic reaction equation of leaching aluminum from alkali-fused SCC in a mixed HCl/NaF system was established.
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18
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Huang P, Zhu R, Zhang X, Zhang W. A milliseconds flash joule heating method for the regeneration of spent cathode carbon. JOURNAL OF ENVIRONMENTAL SCIENCE AND HEALTH. PART A, TOXIC/HAZARDOUS SUBSTANCES & ENVIRONMENTAL ENGINEERING 2022; 57:33-44. [PMID: 35389829 DOI: 10.1080/10934529.2021.2022422] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Revised: 12/10/2021] [Accepted: 12/12/2021] [Indexed: 06/14/2023]
Abstract
Spent cathode carbon (SCC) blocks of aluminum electrolytic cell were hazardous waste produced in the production of electrolytic aluminum. In this present work, a facile, rapid, and economical strategy was proposed to remove fluoride and other toxic substances in the SCC block by the flash joule heating method. SCC after flash joule heating (F-SCC) were prepared in different flash voltages and number of passes; the chemical composition, microscopic morphology and carbon configuration of the SCC and F-SCC were described in detail. The results show that the purification efficiency depends upon the flash voltages and pass number. In terms of flash voltage, 150 V (5.62 kJ/g) is the optimal voltage to maintain the micro-expansion characteristics of the cathode carbon. Multiple flash joule heating can not only maintain its high-graphitization carbon, but also improve its micro-expansion characteristics. In addition, the electrochemical performance of F-SCC was characterized, and F-SCC displayed excellence capacitance performance. The low-cost, rapid -regeneration method based on the flash joule heating provides an effective method for the clean recycling and high-value utilization of carbonized solid waste.
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Affiliation(s)
- Pengfei Huang
- Key Laboratory of Coal Processing and Efficient Utilization of Ministry of Education, China University of Mining and Technology, Xuzhou, Jiangsu, China
| | - Rongtao Zhu
- Key Laboratory of Coal Processing and Efficient Utilization of Ministry of Education, China University of Mining and Technology, Xuzhou, Jiangsu, China
- School of Chemical Engineering and Technology, China University of Mining and Technology, Xuzhou, Jiangsu, China
| | - Xinxi Zhang
- Key Laboratory of Coal Processing and Efficient Utilization of Ministry of Education, China University of Mining and Technology, Xuzhou, Jiangsu, China
- School of Chemical Engineering and Technology, China University of Mining and Technology, Xuzhou, Jiangsu, China
| | - Wenjun Zhang
- School of Chemical Engineering and Technology, China University of Mining and Technology, Xuzhou, Jiangsu, China
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19
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Modelling of the Erosive Dissolution of Metal Oxides in a Deep Eutectic Solvent—Choline Chloride/Sulfosalicylic Acid—Assisted by Ultrasonic Cavitation. METALS 2021. [DOI: 10.3390/met11121964] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Here we report on the results concerning the influence of ultrasound on the dissolution process of metal oxides CoO, Ni2O3 and Mn2O3 in choline chloride/sulfosalicylic acid as a deep eutectic solvent. The mechanism of dissolution under cavitation conditions with ultrasonic assistance is described. Theoretical research resulted in equations describing the dissolution process kinetics and linking its basic parameters. Optimal conditions for the most effective ultrasound application were found. Experimental data on dissolution kinetics of metal oxides in deep eutectic solvents was also obtained. It was discovered that experimental data correlates well with theoretical calculations, which confirms the correctness of developing a picture about the physicochemical nature of the process under study.
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20
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Zhang J, Teng Z, Han K, Li Y, Wang M. Co-combustion characteristics and kinetics of meager coal and spent cathode carbon block by TG-MS analysis. ARAB J CHEM 2021. [DOI: 10.1016/j.arabjc.2021.103198] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
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21
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Detoxified Spent Pot Lining from Aluminum Production as (Alumino-)Silicate Source for Composite Cement and AutoClaved Aerated Concrete. APPLIED SCIENCES-BASEL 2021. [DOI: 10.3390/app11083715] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
New sources of supplementary cementitious materials (SCMs) are needed to meet the future demand. A potential new source of SCM is spent pot lining, a residue from aluminum production. The present work showed that the refined aluminosilicate part of spent pot lining (SPL) has a moderate chemical reactivity in a cementitious system measured in the R3 calorimetry test, comparable to commercially used coal fly ash. The reaction of SPL led to the consumption of Ca(OH)2 in a cement paste beyond 7 days after mixing. At 28 and 90 days a significant contribution to strength development was therefore observed, reaching a relative strength, which is similar to composite cements with coal fly ash. At early age a retardation of the cement hydration is caused by the SPL, which should most likely be associated with the presence of trace amounts of NH3. The spent pot lining is also investigated as silica source for autoclaved aerated concrete blocks. The replacement of quartz by spent pot lining did not show an adverse effect on the strength-density relation of the lightweight blocks up to 50 wt% quartz substitution. Overall, spent pot lining can be used in small replacement volumes (30 wt%) as SCM or as replacement of quartz (50 wt%) in autoclaved aerated concrete blocks.
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22
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Yao Z, Zhong Q, Xiao J, Ye S, Tang L, Zhang Z. An environmental-friendly process for dissociating toxic substances and recovering valuable components from spent carbon cathode. JOURNAL OF HAZARDOUS MATERIALS 2021; 404:124120. [PMID: 33068991 DOI: 10.1016/j.jhazmat.2020.124120] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 08/29/2020] [Accepted: 09/25/2020] [Indexed: 06/11/2023]
Abstract
Spent carbon cathode (SCC), a hazardous solid waste discharged from the aluminum electrolysis industry, has a serious environmental pollution risk. This study aims to explore an environmental friendly process for dissociating toxic substances and recovering valuable components from SCC. Parameters of molten salt-assisted roasting and water leaching were optimized. A possible dissociation mechanism of toxic substances was proposed. Results showed that 99.12% of cyanide was decomposed and 96.63% of fluoride was leached under optimal conditions. The recovery route of fluoride was designed according to the solution equilibrium chemical calculation and the difference in solubility and particle size between the recovered products. Exhaust gas with a high concentration of CO and CO2 was used for the carbonation of the leaching solution to recover cryolite. Effects of reaction conditions on precipitation mass and phase composition of recovered cryolite were investigated in detail. Characterization results indicated that the crystallinity and particle size of cryolite recovered under optimal conditions were extremely similar to those of commercial products. Finally, NaF and Na2CO3 were separated and recovered via evaporative crystallization combined with selective filtration. This proposed process with circular economy and green chemistry characteristics is expected to recover valuable components while minimizing environmental hazards of SCC.
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Affiliation(s)
- Zhen Yao
- School of Metallurgy and Environment, Central South University, Changsha 410083, PR China; School of Materials and Architectural Engineering, Guizhou Normal University, Guiyang 550001, PR China
| | - Qifan Zhong
- School of Metallurgy and Environment, Central South University, Changsha 410083, PR China; National Engineering Laboratory for Efficient Utilization of Refractory Nonferrous Metal Resources, Central South University, Changsha 410083, PR China.
| | - Jin Xiao
- School of Metallurgy and Environment, Central South University, Changsha 410083, PR China; National Engineering Laboratory for Efficient Utilization of Refractory Nonferrous Metal Resources, Central South University, Changsha 410083, PR China.
| | - Shengchao Ye
- School of Metallurgy and Environment, Central South University, Changsha 410083, PR China
| | - Lei Tang
- School of Metallurgy and Environment, Central South University, Changsha 410083, PR China
| | - Zhenhua Zhang
- School of Metallurgy and Environment, Central South University, Changsha 410083, PR China
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23
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Dynamic evolutionary model based on a multi-sampling inherited HAPFNN for an aluminium electrolysis manufacturing system. Appl Soft Comput 2021. [DOI: 10.1016/j.asoc.2020.106925] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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24
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Hu Y, Guo P, Wang S, Zhang L. Leaching Kinetics of Antimony from Refractory Gold Ore in Alkaline Sodium Sulfide under Ultrasound. Chem Eng Res Des 2020. [DOI: 10.1016/j.cherd.2020.09.029] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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25
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Zhang G, Sun G, Chen Z, Evrendilek F, Liu J. Water-soluble fluorine detoxification mechanisms of spent potlining incineration in response to calcium compounds. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2020; 266:115420. [PMID: 32829031 DOI: 10.1016/j.envpol.2020.115420] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2020] [Revised: 07/19/2020] [Accepted: 08/10/2020] [Indexed: 06/11/2023]
Abstract
In this study, the detoxification mechanisms of water-soluble fluorine in the bottom ash and the distribution of fluorine during the spent potlining (SPL) incineration were characterized in response to four calcium compounds using an experimental tube furnace. CaSiO3, CaO, Ca(OH)2, and CaCO3-assisted SPL incineration converted NaF to low toxicity compounds in the bottom ash yielding a conversion range of 54.24-99.45% relative to the individual SPL incineration. The two main mechanisms of the fluorine transformation were the formations of CaF2 and Ca4Si2O7F2. The fluorine transformation efficiency was greater with CaSiO3 than CaO, Ca(OH)2, and CaCO3. Our simulations demonstrated that SiO2 enhanced the conversion of NaF. The fluorine leaching content of the bottom ash was estimated at 13.71 mg⋅L-1 after the SPL co-incineration with CaSiO3 (Ca:F = 1.2:1). The acid-alkali solutions had no significant effect on the fluorine leaching content of the bottom ash when 3 ≤ pH ≤ 12. Fluorine during the SPL co-incineration with CaSiO3 (Ca:F = 1.2:1) at 850 °C for 60 min was partitioned into 83.37, 13.90, and 2.72% in the bottom ash, fly ash, and flue gas, respectively. The transformation and detoxification mechanisms of water-soluble fluorine provide new insights into controls on fluorine emission from the SPL incineration.
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Affiliation(s)
- Gang Zhang
- Engineering Research Center of None-food Biomass Efficient Pyrolysis and Utilization Technology of Guangdong Higher Education Institutes, Dongguan University of Technology, Dongguan, 523808, China
| | - Guang Sun
- Engineering Research Center of None-food Biomass Efficient Pyrolysis and Utilization Technology of Guangdong Higher Education Institutes, Dongguan University of Technology, Dongguan, 523808, China; School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou, 510006, China
| | - Zihong Chen
- School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou, 510006, China
| | - Fatih Evrendilek
- Department of Environmental Engineering, Bolu Abant Izzet Baysal University, Bolu, 14052, Turkey
| | - Jingyong Liu
- School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou, 510006, China.
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26
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Abstract
Abstract
Kinetics, as a fundamental requirement of nearly all industrial activities and engineering researches, plays a great role in leaching processes. Although there are many pieces of research on its application, there is not a clear pathway for investigating the kinetics of leaching and researchers usually follow different strategies in their studies. The conventional investigation techniques, which usually do not consider the mixed mechanisms and possibility of any change in the mechanism, normally include many calculations, plots, and inadequate capabilities to detect changes in the controlling mechanism of leaching. In this review, the main mathematical models of leaching and all possible scenarios are presented and discussed. The effect of various leaching parameters (including leaching agent, temperature, particle size, agitation, and solid to liquid ratio) on the rate of dissolution is summarized. Besides, two main approaches of rate determination step (single controlling mechanism and combined resistances method) are described and compared by reporting related equations and suitable examples. A technique to detect any changes in the leaching controlling mechanism is introduced and the alternatives to confirm the results are described. Additional models and equations were suggested for the cases that there is no agreement between data and the conventional models. Also, situations which are ignored in simple models (e.g., reversibility of the leaching reactions, adsorption and desorption of leached species, influence of charge and surface potential, existence of multiple reactants in the solid, galvanic effect, wide particle size distribution, etc.) to develop more legalistic models are discussed. Considering various possible mechanisms in the kinetics of leaching, equations are derived for industrial leaching reactors.
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27
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Li R, Lu T, Xie M, Liu F. Analysis on thermal behavior of fluorides and cyanides for heat-treating spent cathode carbon blocks from aluminum smelters by TG/DSC-MS & ECSA®. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2020; 189:110015. [PMID: 31830602 DOI: 10.1016/j.ecoenv.2019.110015] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2019] [Revised: 11/23/2019] [Accepted: 11/26/2019] [Indexed: 06/10/2023]
Abstract
This paper adopts a novel data-processing method of ECSA® based on TG/DSC-MS system to basically study the characteristics of release and conversion of fluorides and cyanides during heat treatment of the spent cathode carbon block (SCCB). All the experiments were conducted at 10 K⋅min-1 heating rate and under Ar or Ar-O2 atmospheres. The results indicate that the release of fluorides was just a steady but slow phase transition process under both Ar and Ar-O2 atmospheres, which can be comparatively accelerated when the carbon material was burnt. The cyanides were effectively decomposed at high temperature and at Ar-O2 atmosphere, with around three quarters of the cyanides being converted to the N2 and nearly a quarter being to the NO. Finally, analysis on the flue gas composition indicates that it had a more complicated composition of CO2, N2, NO, NO2, HCN under Ar-O2 atmosphere but only had a composition of CO2 and NO under Ar atmosphere.
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Affiliation(s)
- Rongbin Li
- School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing, 100083, China
| | - Tingting Lu
- School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing, 100083, China
| | - Mingzhuang Xie
- School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing, 100083, China
| | - Fengqin Liu
- School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing, 100083, China.
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28
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Nejadshafiee V, Naeimi H, Islami MR. Sonochemical synthesis of library benzodiazepines using highly efficient molecular ionic liquid supported on Fe‐MCM‐41 nanocomposites as a recyclable catalyst. Appl Organomet Chem 2019. [DOI: 10.1002/aoc.5072] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Vajihe Nejadshafiee
- Department of Organic Chemistry, Faculty of ChemistryUniversity of Kashan Kashan 87317 I.R. Iran
- Chemistry DepartmentShahid Bahonar University of Kerman Kerman 76169 I.R. Iran
| | - Hossein Naeimi
- Department of Organic Chemistry, Faculty of ChemistryUniversity of Kashan Kashan 87317 I.R. Iran
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29
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Sun G, Zhang G, Liu J, Xie W, Kuo J, Lu X, Buyukada M, Evrendilek F, Sun S. Thermogravimetric and mass-spectrometric analyses of combustion of spent potlining under N 2/O 2 and CO 2/O 2 atmospheres. WASTE MANAGEMENT (NEW YORK, N.Y.) 2019; 87:237-249. [PMID: 31109523 DOI: 10.1016/j.wasman.2019.01.047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Revised: 01/24/2019] [Accepted: 01/31/2019] [Indexed: 06/09/2023]
Abstract
Thermal decomposition and gaseous evolution of the spent potlining (SPL) combustion were quantified using thermogravimetric and mass-spectrometric analyses in CO2/O2 and N2/O2 atmospheres using three heating rates (15, 20 and 25 °C/min). The thermal decomposition of SPL occurred mainly between 450 and 800 °C. Based on the four kinetic methods of Friedman, Starink, Kissinger-Akahira-Sunose and Flynn-Wall-Ozawa under the various conversion degrees (α) from 0.1 to 0.7, the lowest apparent activation energy was estimated at 149.81 kJ/mol in the 70% CO2/30% O2 atmosphere. The pre-exponential factor, and changes in entropy, enthalpy and free Gibbs energy were also estimated. The reaction model did not suggest a single reaction of the SPL combustion. With the α value of 0.25-0.7, the following function best described the reaction based on the Malek method: f(α) = 1/2α and G(α) = lnα2. The gases released during the combustion process included CO2, CO, NOx, HCN, and HF.
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Affiliation(s)
- Guang Sun
- Guangzhou Key Laboratory Environmental Catalysis and Pollution Control, Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, School of Environmental Science and Engineering, Institute of Environmental Health and Pollution Control, Guangdong University of Technology, Guangzhou 510006, China; Department of Energy and Chemical Engineering, Dongguan University of Technology, Dongguan 523808, China
| | - Gang Zhang
- Department of Energy and Chemical Engineering, Dongguan University of Technology, Dongguan 523808, China
| | - Jingyong Liu
- Guangzhou Key Laboratory Environmental Catalysis and Pollution Control, Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, School of Environmental Science and Engineering, Institute of Environmental Health and Pollution Control, Guangdong University of Technology, Guangzhou 510006, China.
| | - Wuming Xie
- Guangzhou Key Laboratory Environmental Catalysis and Pollution Control, Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, School of Environmental Science and Engineering, Institute of Environmental Health and Pollution Control, Guangdong University of Technology, Guangzhou 510006, China
| | - Jiahong Kuo
- Guangzhou Key Laboratory Environmental Catalysis and Pollution Control, Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, School of Environmental Science and Engineering, Institute of Environmental Health and Pollution Control, Guangdong University of Technology, Guangzhou 510006, China
| | - Xingwen Lu
- Guangzhou Key Laboratory Environmental Catalysis and Pollution Control, Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, School of Environmental Science and Engineering, Institute of Environmental Health and Pollution Control, Guangdong University of Technology, Guangzhou 510006, China
| | - Musa Buyukada
- Department of Chemical Engineering, Bolu Abant Izzet Baysal University, Bolu 14052, Turkey
| | - Fatih Evrendilek
- Department of Environmental Engineering, Bolu Abant Izzet Baysal University, Bolu 14052, Turkey; Department of Environmental Engineering, Ardahan University, Ardahan 75002, Turkey
| | - Shuiyu Sun
- Guangzhou Key Laboratory Environmental Catalysis and Pollution Control, Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, School of Environmental Science and Engineering, Institute of Environmental Health and Pollution Control, Guangdong University of Technology, Guangzhou 510006, China
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30
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Yuan J, Xiao J, Tian Z, Yang K, Yao Z. Optimization of Spent Cathode Carbon Purification Process under Ultrasonic Action Using Taguchi Method. Ind Eng Chem Res 2018. [DOI: 10.1021/acs.iecr.7b05351] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Jie Yuan
- School of Metallurgy and Environment, Central South University, Changsha, 410083, PR China
| | - Jin Xiao
- School of Metallurgy and Environment, Central South University, Changsha, 410083, PR China
- National Engineering Laboratory of Efficient Utilization of Refractory Nonferrous Metal Resources, Central South University, Changsha, 410083, PR China
| | - Zhongliang Tian
- School of Metallurgy and Environment, Central South University, Changsha, 410083, PR China
| | - Kai Yang
- School of Metallurgy and Environment, Central South University, Changsha, 410083, PR China
| | - Zhen Yao
- School of Metallurgy and Environment, Central South University, Changsha, 410083, PR China
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31
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Yuan J, Xiao J, Li F, Wang B, Yao Z, Yu B, Zhang L. Co-treatment of spent cathode carbon in caustic and acid leaching process under ultrasonic assisted for preparation of SiC. ULTRASONICS SONOCHEMISTRY 2018; 41:608-618. [PMID: 29137793 DOI: 10.1016/j.ultsonch.2017.10.027] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Revised: 10/26/2017] [Accepted: 10/26/2017] [Indexed: 06/07/2023]
Abstract
Spent cathode carbon (SCC) from aluminum electrolysis has been treated in ultrasonic-assisted caustic leaching and acid leaching process, and purified SCC used as carbon source to synthesize silicon carbide (SiC) was investigated. Chemical and mineralogical properties have been characterized by X-ray diffraction (XRD), X-ray fluorescence (XRF), scanning electron microscopy (SEM), and thermogravimetry and differential scanning calorimetry (TGA-DSC). Various experimental factors temperature, time, liquid-solid ratio, ultrasonic power, and initial concentration of alkali or acid affecting on SCC leaching result were studied. After co-treatment with ultrasonic-assisted caustic leaching and acid leaching, carbon content of leaching residue was 97.53%. SiC power was synthesized by carbothermal reduction at 1600 °C, as a result of yield of 76.43%, and specific surface area of 4378 cm2/g. This is the first report of using purified SCC and gangue to prepare SiC. The two industrial wastes have been used newly as secondary sources. Furthermore, ultrasonic showed significant effect in SCC leaching process.
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Affiliation(s)
- Jie Yuan
- School of Metallurgy and Environment, Central South University, Changsha 410083, PR China
| | - Jin Xiao
- School of Metallurgy and Environment, Central South University, Changsha 410083, PR China; National Engineering Laboratory of Efficient Utilization of Refractory Nonferrous Metal Resources, Central South University, Changsha 410083, PR China.
| | - Fachuang Li
- School of Metallurgy and Environment, Central South University, Changsha 410083, PR China
| | - Bingjie Wang
- School of Metallurgy and Environment, Central South University, Changsha 410083, PR China
| | - Zhen Yao
- School of Metallurgy and Environment, Central South University, Changsha 410083, PR China
| | - Bailie Yu
- School of Metallurgy and Environment, Central South University, Changsha 410083, PR China
| | - Liuyun Zhang
- School of Metallurgy and Environment, Central South University, Changsha 410083, PR China
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