The mining process involves drilling and excavation, resulting in the production of waste rock and tailings. The waste materials are then removed and stored in designated areas. This study aims to evaluate the mechani...The mining process involves drilling and excavation, resulting in the production of waste rock and tailings. The waste materials are then removed and stored in designated areas. This study aims to evaluate the mechanical strength and the environmental and economic impact of using Coltan Mining Waste (CMW) as a substitute for aggregates in concrete and mortar production. To achieve this, the CMW needs to be characterised. The Dreux Gorisse method was primarily used to produce concrete with a strength of 20 MPa at 28 days. The mortars, on the other hand, were formulated according to the NF P 18-452 standard. The environmental impact of using CMW as substitutes for natural aggregates in the production of concrete and mortar was analysed using SimaPro software. The results showed that mortars and concrete made with CMW have comparable compressive strengths to the reference mortar and concrete;reduce the negative impact on ecosystem quality, human health, resources, and climate change. It has also been shown that the substitution of aggregates by CMW reduces the cost of concrete and mortar as a function of the distance from the aggregate footprint.展开更多
铌、钽作为稀有金属,其熔点高、密度大、耐高温、超导性等优异性能使其在人类社会多个领域具有不可替代性,也是近20年及未来全球都极为重视的战略资源。了解铌钽在不同岩浆系统中的分异富集及不同类型铌钽矿床的成矿机制是至关重要的。...铌、钽作为稀有金属,其熔点高、密度大、耐高温、超导性等优异性能使其在人类社会多个领域具有不可替代性,也是近20年及未来全球都极为重视的战略资源。了解铌钽在不同岩浆系统中的分异富集及不同类型铌钽矿床的成矿机制是至关重要的。前人已有研究认为影响铌钽分异富集的主要因素有岩浆系统的碱性程度、熔体中水的含量、熔体温度,以及主要含铌、钽的矿物(铌钽铁矿、黑云母、多硅白云母等)的分离结晶和部分熔融过程中的结晶与熔融。此外,高浓度的助熔剂(F,Li, Be, P,H_2O)对铌钽分异富集也有不可忽视的作用。前人研究发现一些铌钽矿床表现出岩浆结晶分异成矿作用特征,但在铌钽矿化发育区域,常伴有强烈的钠长石化和锂云母化等交代作用现象,因此单一的岩浆结晶分异作用或热液交代作用都不能全面地解释复杂的铌钽成矿作用。铌钽分异富集成矿过程中,结晶分异和热液交代作用占比如何,哪个阶段更加富集铌和钽,这些问题有待进一步解决。此外,由于其高铀低普通铅的特性,铌铁矿族矿物也被广泛应用于LA-ICP-MS U-Pb定年,常用标样为Coltan139,其激光分辨率有待进一步提高以解决铌钽矿物复杂化学分带的激光原位定年问题。铌钽矿物Lu-Hf同位素工作开展较少,未来需继续开展同位素工作以示踪物源并指示铌钽分异富集成矿机制。展开更多
The Mufushan Complex(MFSC),located in northeastern Hunan,is a significant producer of Nb-Ta-Li-Be rare metals in South China.The present study examines the genetic relationship,material provenance,fluid evolution,and ...The Mufushan Complex(MFSC),located in northeastern Hunan,is a significant producer of Nb-Ta-Li-Be rare metals in South China.The present study examines the genetic relationship,material provenance,fluid evolution,and metallogeny of the co-developed ore-free pegmatite(OFP)and ore-bearing pegmatite(OBP)in granite-related pegmatite-type Nb-Ta rare-metal deposits in MFSC.Three minerals(columbite-tantalite(coltan),zircon,and monazite)were chosen for analysis.The coltan grains display both primary crystallization structures(crystal homogeneity,oscillatory zonings,and primary growth rims)resulting from equilibrium and disequilibrium reactions due to localized changes in the physicochemical conditions and environment,as well as later replacement structures(alteration rims,patches,irregular zonations,and complex zonations)from metasomatic replacement processes related to hydrothermal fluid activity.The coltan yielded two weighted mean^(206)Pb/^(238)U ages of 138.1±2.1 Ma and 125.3±2.0 Ma corresponding to magmatic and hydrothermal Nb-Ta mineralization ages.For the OFP,zircons also yielded two weighted mean^(206)Pb/^(238)U ages of 138.4±0.8 Ma and 131.5±0.7 Ma,whereas monazite gave a weighted mean U-Pb age 142.9±1.2 Ma.The ages of 142-138 Ma and 131 Ma represent the early and late stages of OFP crystallization and barren pegmatites in the MFSC,respectively.Zircon Lu-Hf isotopic compositions link rare-metal metallogenesis to the Lengjiaxi Group,which was the source material to the Mufushan composite batholith.Calculatedε_(Hf)(t)values and TDM2 ages from the OFP(-7.6 to-3.6 and 1676-1418 Ma,respectively)and the OBP(-14.1 to+4.9 and 2976-1548 Ma,respectively)are akin to those of schists and metasandstones of the metasedimentary Lengjiaxi Group.We propose a long-lived(ca.13-Myr)event involving two metallogenic episodes of Nb-Ta mineralization in the Mufushan region.This study demonstrates the potential of zircon,coltan,and monazite for fingerprinting minerals and classifying the mineralization potential of pegmatite veins.展开更多
文摘The mining process involves drilling and excavation, resulting in the production of waste rock and tailings. The waste materials are then removed and stored in designated areas. This study aims to evaluate the mechanical strength and the environmental and economic impact of using Coltan Mining Waste (CMW) as a substitute for aggregates in concrete and mortar production. To achieve this, the CMW needs to be characterised. The Dreux Gorisse method was primarily used to produce concrete with a strength of 20 MPa at 28 days. The mortars, on the other hand, were formulated according to the NF P 18-452 standard. The environmental impact of using CMW as substitutes for natural aggregates in the production of concrete and mortar was analysed using SimaPro software. The results showed that mortars and concrete made with CMW have comparable compressive strengths to the reference mortar and concrete;reduce the negative impact on ecosystem quality, human health, resources, and climate change. It has also been shown that the substitution of aggregates by CMW reduces the cost of concrete and mortar as a function of the distance from the aggregate footprint.
文摘铌、钽作为稀有金属,其熔点高、密度大、耐高温、超导性等优异性能使其在人类社会多个领域具有不可替代性,也是近20年及未来全球都极为重视的战略资源。了解铌钽在不同岩浆系统中的分异富集及不同类型铌钽矿床的成矿机制是至关重要的。前人已有研究认为影响铌钽分异富集的主要因素有岩浆系统的碱性程度、熔体中水的含量、熔体温度,以及主要含铌、钽的矿物(铌钽铁矿、黑云母、多硅白云母等)的分离结晶和部分熔融过程中的结晶与熔融。此外,高浓度的助熔剂(F,Li, Be, P,H_2O)对铌钽分异富集也有不可忽视的作用。前人研究发现一些铌钽矿床表现出岩浆结晶分异成矿作用特征,但在铌钽矿化发育区域,常伴有强烈的钠长石化和锂云母化等交代作用现象,因此单一的岩浆结晶分异作用或热液交代作用都不能全面地解释复杂的铌钽成矿作用。铌钽分异富集成矿过程中,结晶分异和热液交代作用占比如何,哪个阶段更加富集铌和钽,这些问题有待进一步解决。此外,由于其高铀低普通铅的特性,铌铁矿族矿物也被广泛应用于LA-ICP-MS U-Pb定年,常用标样为Coltan139,其激光分辨率有待进一步提高以解决铌钽矿物复杂化学分带的激光原位定年问题。铌钽矿物Lu-Hf同位素工作开展较少,未来需继续开展同位素工作以示踪物源并指示铌钽分异富集成矿机制。
基金the National Natural Science Foundation of China(No.92162103)the Natural Science Foundation of Hunan Province(No.2021J30699)+2 种基金the Geological Exploration Project of the Hunan Provincial Institute of Land and Resources Planning(Grant No.20190604)the Science and Technology Innovation program of the Hunan Province(Grant No.2021RC4055)the Fundamental Research Funds for the Central Universities of Central South University(Grant No.CX20200310).
文摘The Mufushan Complex(MFSC),located in northeastern Hunan,is a significant producer of Nb-Ta-Li-Be rare metals in South China.The present study examines the genetic relationship,material provenance,fluid evolution,and metallogeny of the co-developed ore-free pegmatite(OFP)and ore-bearing pegmatite(OBP)in granite-related pegmatite-type Nb-Ta rare-metal deposits in MFSC.Three minerals(columbite-tantalite(coltan),zircon,and monazite)were chosen for analysis.The coltan grains display both primary crystallization structures(crystal homogeneity,oscillatory zonings,and primary growth rims)resulting from equilibrium and disequilibrium reactions due to localized changes in the physicochemical conditions and environment,as well as later replacement structures(alteration rims,patches,irregular zonations,and complex zonations)from metasomatic replacement processes related to hydrothermal fluid activity.The coltan yielded two weighted mean^(206)Pb/^(238)U ages of 138.1±2.1 Ma and 125.3±2.0 Ma corresponding to magmatic and hydrothermal Nb-Ta mineralization ages.For the OFP,zircons also yielded two weighted mean^(206)Pb/^(238)U ages of 138.4±0.8 Ma and 131.5±0.7 Ma,whereas monazite gave a weighted mean U-Pb age 142.9±1.2 Ma.The ages of 142-138 Ma and 131 Ma represent the early and late stages of OFP crystallization and barren pegmatites in the MFSC,respectively.Zircon Lu-Hf isotopic compositions link rare-metal metallogenesis to the Lengjiaxi Group,which was the source material to the Mufushan composite batholith.Calculatedε_(Hf)(t)values and TDM2 ages from the OFP(-7.6 to-3.6 and 1676-1418 Ma,respectively)and the OBP(-14.1 to+4.9 and 2976-1548 Ma,respectively)are akin to those of schists and metasandstones of the metasedimentary Lengjiaxi Group.We propose a long-lived(ca.13-Myr)event involving two metallogenic episodes of Nb-Ta mineralization in the Mufushan region.This study demonstrates the potential of zircon,coltan,and monazite for fingerprinting minerals and classifying the mineralization potential of pegmatite veins.
