Extraction of valuable components from coal gangue through thermal activation and HNO3 leaching

Shao, Shuang; Ma, Baozhong; Wang, Chengyan; Chen, Yongqiang

doi:10.1016/j.jiec.2022.06.033

Cited by 38 publications

(6 citation statements)

References 43 publications

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“…Generally, research on the resource utilization of CG is based on its physical and chemical properties and composition structure. At present, CG is mainly used in filling mining [7] , for the preparation of building materials [8,9] , as a fuel [10] , for soil improvement [11] , for the extraction of valuable elements [12] , and to obtain adsorbent materials [13] . In addition, the preparation of electromagnetic wave (EMW)-absorbing materials has emerged as a new green and cost-effective method for the valorization of CG.…”

Section: Introductionmentioning

confidence: 99%

Coal gangue as an efficient absorber for X-band applications

Zhu,

Gao,

Zhang

2024

Preprint

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Coal mining generates coal gangue (CG), whose poses considerable ecological challenges. Therefore, using CG in the preparation of electromagnetic wave (EMW)-absorbing materials has emerged as a promising approach for its high-value utilization. In this study, CG was dried and ball-milled. The microscopic morphology, element composition, elemental chemical state, and thermal stability of CG were characterized analyses. The EMW absorption performance of CG in the X-band was tested at filling ratios of 10%, 20%, and 40%. The results showed that CG mainly consisted of SiO2, Al2O3, and C. The CG/paraffin absorber exhibited strong reflection loss (RL) at a relatively thin thickness. When the thickness of the CG/paraffin absorber was 4.0 mm, the minimum RL reached − 50.2 dB at 8.8 GHz. The simulation results of the radar cross section showed that the absorbing coating can reduce EMW scattering on a perfectly conductive substrate, which renders it promising as an excellent EMW-absorbing material.

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Section: Introductionmentioning

confidence: 99%

Coal gangue as an efficient absorber for X-band applications

Zhu,

Gao,

Zhang

2024

Preprint

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“…Ye et al [ 42 ] successfully synthesized a ZSM-5 zeolite catalyst with tailings as the raw material using a template-free method. Coal gangue mainly contains SiO 2 and Al 2 O 3 ; they account for approximately 50–80% of the coal gangue component [ 43 ], making it an appropriate raw material for the synthesis of ZSM-5 molecular sieves. Although there has been progress in the preparation of ZSM-5 molecular sieves from coal gangue in recent years, shortcomings remain.…”

Section: Introductionmentioning

confidence: 99%

Preparation of a High-Silicon ZSM-5 Molecular Sieve Using Only Coal Gangue as the Silicon and Aluminum Sources

Zheng

Zhou

et al. 2023

Materials

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The traditional preparation of ZSM-5 molecular sieves relies on chemical reagents to provide silicon and aluminum sources, which are limited as raw materials and cannot be commonly used in production practice. Using coal gangue as the raw material and using medium-temperature chlorination roasting and the pressure acid leaching process to control the silicon–aluminum ratio [n(Si/Al)] of coal gangue, a ZSM-5 molecular sieve was prepared using the alkali melting hydrothermal method. The pressure acid leaching process solved the limitation that kaolinite and mica cannot simultaneously be activated. Under optimal conditions, the n(Si/Al) of the coal gangue increased from 6.23 to 26.14 and complied with the requirements for the synthesis n(Si/Al) of a ZSM-5 molecular sieve. The effect of n(Si/Al) on the preparation of the ZSM-5 molecular sieve was studied. Finally, spherical granular ZSM-5 molecular sieve material with a microporous specific surface area of 169.6329 m2/g, an average pore diameter of 0.6285 nm, and a pore volume of 0.0988 cm3/g was prepared. Providing ideas for the high-value utilization of coal gangue, it is significant for solving the problem of coal gangue solid waste, as well as the problem of ZSM-5 molecular sieve feed stock.

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“…So more iron ions are hydrolyzed into hematite at high temperatures, which achieves selective leaching of Al; (2) the scaling problem of the autoclave caused by the formation of CaSO 4 when H 2 SO 4 is used as the medium can be avoided; (3) the decomposition temperature of Al(NO 3 ) 3 ·9H 2 O is only 250 °C, which is far below 1000–1200 °C of AlCl 3 ·6H 2 O and 1350 °C of Al 2 (SO 4 ) 3 ·18H 2 O . Hence the thermolysis of Al(NO 3 ) 3 ·9H 2 O and the regeneration of HNO 3 are bound to greatly reduce the cost of acid recovery Al from coal gangue/fly ash; and (4) our team has successfully applied HNO 3 pressure leaching technology to the treatment of laterite ore, realizing the recovery of HNO 3 and the enrichment of Fe in slag. − Eighty percent of Al in coal fly ash , and 95% of Al in coal gangue were leached out via HNO 3 pressurization technology by our team, but 6% of Fe in coal fly ash and 2% of Fe in coal gangue still inevitably entered the leach liquor. To obtain pure Al 2 O 3 by direct pyrolysis at a low cost, the removal of Fe 3+ from the leach liquor is a thorny challenge …”

Section: Introductionmentioning

confidence: 99%

Phase Diagram of the Al(NO₃)₃–Fe(NO₃)₃–H₂O(−HNO₃) System and Its Application in the Separation of Al³⁺ and Fe³⁺

Shi

Shao

et al. 2023

J. Chem. Eng. Data

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An original technology named HNO3 pressure leaching has been proposed by our team to leach Al from coal gangue and fly ash. Although the preliminary separation of Al and Fe had been achieved during leaching, a small amount of Fe impurity was still unavoidably dissolved into the leach liquor. To obtain pure Al2O3 during subsequent pyrolysis, it is imperative to synchronously remove Fe3+ during the crystallization of Al(NO3)3·9H2O. Herein, the phase equilibria of the Al(NO3)3–Fe(NO3)3–H2O(−HNO3) system at 25–40 °C and 0–8.12 mol kg–1 of HNO3 molality were investigated. The results indicated that the ternary system was a simple cosaturated type consisting of an immutable point, two univariate curves, and two crystallization regions. Notably, the solubility and crystallization region of Al(NO3)3·9H2O were barely impacted by acidity, while the opposite was true for Fe(NO3)3·9H2O. This finding was instructive for the crystallization of Fe(NO3)3·9H2O from the liquor with high Fe and low Al. Moreover, a high crystallization yield could be obtained at low temperatures. Finally, an appropriate crystallization procedure was provided. This study is expected to provide basic data and theoretical support for the crystallization and separation of mixed nitrates containing Al and Fe.

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Extraction of valuable components from coal gangue through thermal activation and HNO3 leaching

Cited by 38 publications

References 43 publications

Coal gangue as an efficient absorber for X-band applications

Coal gangue as an efficient absorber for X-band applications

Preparation of a High-Silicon ZSM-5 Molecular Sieve Using Only Coal Gangue as the Silicon and Aluminum Sources

Phase Diagram of the Al(NO₃)₃–Fe(NO₃)₃–H₂O(−HNO₃) System and Its Application in the Separation of Al³⁺ and Fe³⁺

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Extraction of valuable components from coal gangue through thermal activation and HNO3 leaching

Cited by 38 publications

References 43 publications

Coal gangue as an efficient absorber for X-band applications

Coal gangue as an efficient absorber for X-band applications

Preparation of a High-Silicon ZSM-5 Molecular Sieve Using Only Coal Gangue as the Silicon and Aluminum Sources

Phase Diagram of the Al(NO3)3–Fe(NO3)3–H2O(−HNO3) System and Its Application in the Separation of Al3+ and Fe3+

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Product

Resources

About

Phase Diagram of the Al(NO₃)₃–Fe(NO₃)₃–H₂O(−HNO₃) System and Its Application in the Separation of Al³⁺ and Fe³⁺