Minerals
Latest Publications


TOTAL DOCUMENTS

3742
(FIVE YEARS 3586)

H-INDEX

32
(FIVE YEARS 24)

Published By Mdpi Ag

2075-163x
Updated Friday, 25 June 2021

Minerals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 671
Author(s):  
Constanza Rivas-Romero ◽  
Martin Reich ◽  
Fernando Barra ◽  
Daniel Gregory ◽  
Sergio Pichott

Porphyry Cu-Mo deposits are among the world’s largest source of Cu, Mo, and Re, and are also an important source of other trace elements, such as Au and Ag. Despite the fact that chalcopyrite, bornite, and pyrite are the most common sulfides in this deposit type, their trace element content remains poorly constrained. In particular, little is known about minor and trace elements partitioning into Cu-(Fe) sulfides as a function of temperature and pH of the hydrothermal fluid. In this study, we report a comprehensive geochemical database of chalcopyrite, bornite, and pyrite in the super-giant Chuquicamata porphyry Cu-Mo deposit in northern Chile. The aim of our study, focused on the new Chuquicamata Underground mine, was to evaluate the trace element composition of each sulfide from the different hydrothermal alteration assemblages in the deposit. Our approach combines the electron microprobe analysis (EMPA) and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) of sulfide minerals obtained from six representative drill cores that crosscut the chloritic (propylitic), background potassic, intense potassic, and quartz-sericite (phyllic) alteration zones. Microanalytical results show that chalcopyrite, bornite, and pyrite contain several trace elements, and the concentration varies significantly between hydrothermal alteration assemblages. Chalcopyrite, for example, is a host of Se (≤22,000 ppm), Pb (≤83.00 ppm), Sn (≤68.20 ppm), Ag (≤45.1 ppm), Bi (≤25.9 ppm), and In (≤22.8 ppm). Higher concentrations of Se, In, Pb, and Sn in chalcopyrite are related to the high temperature background potassic alteration, whereas lower concentrations of these elements are associated with the lower temperature alteration types: quartz-sericite and chloritic. Bornite, on the other hand, is only observed in the intense and background potassic alteration zones and is a significant host of Ag (≤752 ppm) and Bi (≤2960 ppm). Higher concentrations of Ag and Sn in bornite are associated with the intense potassic alteration, whereas lower concentrations of those two elements are observed in the background potassic alteration. Among all of the sulfide minerals analyzed, pyrite is the most significant host of trace elements, with significant concentrations of Co (≤1530 ppm), Ni (≤960 ppm), Cu (≤9700 ppm), and Ag (≤450 ppm). Co, Ni, Ag, and Cu concentration in pyrite vary with alteration: higher Ag and Cu concentrations are related to the high temperature background potassic alteration. The highest Co contents are associated with lower temperature alteration types (e.g., chloritic). These data indicate that the trace element concentration of chalcopyrite, bornite, and pyrite changed as a function of hydrothermal alteration is controlled by several factors, including temperature, pH, fO2, fS2, and the presence of co-crystallizing phases. Overall, our results provide new information on how trace element partitioning into sulfides relates to the main hydrothermal and mineralization events controlling the elemental budget at Chuquicamata. In particular, our data show that elemental ratios in chalcopyrite (e.g., Se/In) and, most importantly, pyrite (e.g., Ag/Co and Co/Cu) bear the potential for vectoring towards porphyry mineralization and higher Cu resources.


Minerals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 673
Author(s):  
Luthando Xolo ◽  
Pulleng Moleko-Boyce ◽  
Hlamulo Makelane ◽  
Nobathembu Faleni ◽  
Zenixole R. Tshentu

The need to drive towards sustainable metal resource recovery from end-of-cycle products cannot be overstated. This review attempts to investigate progress in the development of recycling strategies for the recovery of strategic metals, such as precious metals and base metals, from catalytic converters, e-waste, and batteries. Several methods for the recovery of metal resources have been explored for these waste streams, such as pyrometallurgy, hydrometallurgy, and biohydrometallurgy. The results are discussed, and the efficiency of the processes and the chemistry involved are detailed. The conversion of metal waste to high-value nanomaterials is also presented. Process flow diagrams are also presented, where possible, to represent simplified process steps. Despite concerns about environmental effects from processing the metal waste streams, the gains for driving towards a circular economy of these waste streams are enormous. Therefore, the development of greener processes is recommended. In addition, countries need to manage their metal waste streams appropriately and ensure that this becomes part of the formal economic activity and, therefore, becomes regulated.


Minerals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 674
Author(s):  
Sílvio Junio Ramos ◽  
Duane Azevedo Pinto ◽  
Rafael Silva Guedes ◽  
Yan Nunes Dias ◽  
Cecílio Fróis Caldeira ◽  
...  

Organic materials, such as biochar and organic compost, can reduce P sorption mechanisms and improve soil fertility, benefiting the reclamation of areas impacted by mining. This study evaluated how the chemical properties of Fe mining soil, the adsorption of P onto this substrate, and the growth of the native plant Dioclea apurensis, were affected by the application of açaí biochar (BC), organic compost (OC), and different P doses. Substrate collected from mining soil piles was incubated for 30 days with BC or OC. Each mining substrate with or without the addition of BC or OC received five doses of P (0, 40, 80, 120, and 240 mg∙kg−1 P). The addition of BC or OC promoted an increase in pH and nutrient availability (P, K, Ca, and B) in Fe mining soil. However, plants grown in the unamended mining soil (W) showed higher growth. The maximum P adsorption capacity decreased as a function of the addition of BC. We conclude that the application of BC reduced P sorption, while the application of either OC or BC altered the chemical properties of the soil and caused contrasting effects on P dynamics in Fe mining soil, and these treatments also affected plant growth.


Minerals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 675
Author(s):  
Hui Chao ◽  
Mingcai Hou ◽  
Wenjian Jiang ◽  
Haiyang Cao ◽  
Xiaolin Chang ◽  
...  

The Jurassic was mainly a “greenhouse” period characterized by global warming and by significant peat accumulations in some continental basins. However, studies of Jurassic climate and environments have mainly focused on marine records and only a few on terrestrial sediments. Yili Basin, a mid-latitude terrestrial basin in present Northwest China, included accumulation of the important recoverable coal seams. In this study, geological data, clay mineral analysis, and palynological assemblages were employed on fine-grained samples from the Su’asugou section in southern Yili Basin. The factors (paleoclimate, depositional conditions, and paleo-vegetation) impacting peat accumulation were investigated. The results suggest that the siliciclastics may have been derived from exposed Carboniferous rocks in a continental arc environment. A warm and humid paleoclimate in the Yili basin dominated during the early-Early Jurassic deposition of the Badaowan Formation and the Middle Jurassic deposition of the Xishanyao Formation. This climate contributed to high sedimentary rates and to a high productivity of peat-forming paleo-vegetation that was preserved under dysoxic conditions. In contrast, during the late-Early Jurassic between these two formations, the Sangonghe Formation was an interval of relatively aridity that included red beds preserved under more hypoxic sedimentary conditions, and with an interruption in peat formation and preservation.


Minerals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 672
Author(s):  
Anette Regelous ◽  
Lars Scharfenberg ◽  
Helga De Wall

The origin and evolution of granites remain a matter of debate and several approaches have been made to distinguish between different granite types. Overall, granite classification schemes based on element concentrations and ratios, tectonic settings or the source rocks (I-, A-, S-type) are widely used, but so far, no systematic large-scale study on Th/U ratio variations in granites based on their source or tectonic setting has been carried out, even though these elements show very similar behavior during melting and subsequent processes. We therefore present a compiled study, demonstrating an easy approach to differentiate between S-, A- and I-type granites using Th and U concentrations and ratios measured with a portable gamma ray spectrometer. Th and U concentrations from 472 measurements in S- and I-type granites from the Variscan West-Bohemian Massif, Germany, and 78 measurements from Neoproterozoic A-type Malani granites, India, are evaluated. Our compendium shows significant differences in the average Th/U ratios of A-, I- and S-type granites and thus gives information about the source rock and can be used as an easy classification scheme. Considering all data from the studied A-, I- and S-type granites, Th/U ratios increase with rising Th concentrations. A-type granites have the highest Th/U ratios and high Th concentrations, followed by I-type granites. Th/U ratios in S- to I-type granites are lower than in A-type and I-type granites, but higher than in S-type granites. The variation of Th/U ratios in all three types of granite cannot be explained by fractional crystallization of monazite, zircon and other Th and U bearing minerals alone, but are mainly due to source heterogeneities and uranium mobilization processes.


Minerals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 670
Author(s):  
Kenneth N. Han ◽  
Rina Kim

The selective precipitation of rare earth elements (REEs) in acidic media often plays a key role in the effective extraction of these elements from various sources such as ores and recycling streams. In this study, the precipitation characteristics of REEs with sulfate, a frequently used precipitant, were carefully examined, and the results were compared with those of other precipitants, such as phosphate, oxalate, and fluoride/carbonate systems. Emphasis is given on various forms of precipitates, such as anhydrous sulfate, octa-hydrated sulfate, and sodium double salt, in which the sodium double salt was compared with the anionic double salt precipitation of the fluoride-carbonate system. It was found that anions such as Cl−, NO3−, and SO42− play an important role in the precipitation behavior, particularly through complexation with the dissolved REEs. In general, the effectiveness of precipitation follows the order of sodium double salt, a hydrated form of sulfate, and anhydrous sulfate. In this study, it was observed that the synergistic role of a double salt precipitation, either cationic or anionic, is frequently as effective as that of oxalate and phosphate, even in a low pH range.


Minerals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 667
Author(s):  
H. Kory Cooper ◽  
Antonio Simonetti

The Indigenous inhabitants of Arctic and Subarctic North America had been using native copper for several centuries prior to sustained interaction with Europeans beginning in the 18th century. The connection, if any, between the use of copper in these two adjacent regions is, at present, unclear. The ability to determine the source of native copper artifacts found in greater northwestern North America would inform on the movement of copper via trade and exchange between, and aid in understanding the innovation and diffusion of native copper metallurgy among, ancestral Dene and Inuit People. This paper provides the results of a Lead Isotope Analysis (LIA) pilot study examining Pb isotope ratios of native copper samples from multiple locations in the northern regions of North America. The results from this preliminary study indicate some overlap in Pb isotope ratios between Arctic and Subarctic sources of native copper, and these nonetheless record distinct isotope signatures relative to those associated with other North American native Cu deposits.


Minerals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 668
Author(s):  
Timur Nizamutdinov ◽  
Eugenia Morgun ◽  
Alexandr Pechkin ◽  
Jakub Kostecki ◽  
Andrzej Greinert ◽  
...  

Dynamically developing urbanization causes a number of environmental effects, including those related to the chemical transformation of soils. Relatively less information about the urban areas of the Arctic and Subarctic zones, constructed mostly on permafrost and intensively populated areas can be found. By the example of the analysis of basic soil properties and concentrations of trace metals in the soils of the cities of Salekhard, Urengoy, Nadym, Novy Urengoy and Gaz Sale (the Yamalo-Nenets Autonomous District), as well as various functional zones within the cities, the relationship between the age of the cities, the level of anthropogenic pressure and the type of parent materials and the character of accumulation of metals in the soil profile of urban soils have been described. The direct correlation was found between the content of Pb, Cr, Ni, As and soil sorption characteristics. In young cities built on sandy sediments, there is less accumulation of heavy metals in the topsoil horizons. Relatively higher concentrations of Cu and Cd were noted in soils of industrialized cities, regardless of functional zones. The higher content of Cr, Ni, Cu, Zn, As and Pb has been registered in older zones also frequently used for residential purposes. The calculated values of the PI index for some functional zones of young cities show the medium and high content of heavy metals. The analysis of Igeo and PLI indices shows a large diversity both in relation to individual cities and their functional zones. Soil quality, in spite of the high level of anthropogenic load, was assessed as mostly satisfactory.


Minerals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 669
Author(s):  
Stephan Kaufhold ◽  
Reiner Dohrmann ◽  
Kristian Ufer ◽  
Daniel Svensson ◽  
Patrik Sellin

The present study reports on the analysis of all blocks of the ABM5 test, which is a medium scale bentonite buffer deposition test. In contrast to similar tests, the ABM5 was conducted at higher temperature (up to 250 °C). The aim of the study was to characterize the chemical and mineralogical reactions and to identify the effect of the extraordinarily high temperature. Reactions observed were similar to those observed in previous and/or similar tests covering cation exchange, anion inflow, dissolution and precipitation of C- and S-phases, Fe corrosion, and Mg increase at the heater. Neither the type nor the extent of the different reactions could be related to the significantly higher temperature. However, due to the absence of lubricant used between heater and bentonite, it could be proved that the calcite previously present was dissolved and precipitated as siderite at the contact, pointing towards the importance of the presence of carbonate when considering different Fe corrosion products. Moreover, for the first time, a decrease of the Mg content at the heater was observed, which was probably because a Mg-rich clay was used. The reasons for Mg increase or decrease are still not completely understood.


Minerals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 659
Author(s):  
Mingyang Wei ◽  
Zhidong Bao ◽  
Axel Munnecke ◽  
Wei Liu ◽  
G. William M. Harrison ◽  
...  

Just as in deep-water sedimentary environments, productive source rocks can be developed in an evaporitic platform, where claystones are interbedded with evaporites and carbonates. However, the impact of the paleoenvironment on the organic matter enrichment of shallow water source rocks in an evaporite series has not been well explored. In this study, two wells in the central uplift of the Tarim Basin were systematically sampled and analyzed for a basic geochemical study, including major elements, trace elements, and total organic carbon (TOC), to understand the relationship between TOC and the paleoenvironmental parameters, such as paleosalinity, redox, paleoclimate, paleo-seawater depth, and paleoproductivity. The results show that the Lower–Middle Cambrian mainly developed in a fluctuating salinity, weak anoxic to anoxic, continuous dry and hot, and proper shallow water environment. The interfingering section of evaporites, carbonates, and claystones of the Awatag Fm. have higher paleoproductivity and higher enrichment of organic matter. Paleosalinity, redox, paleoclimate, paleo-seawater depth, and paleoproductivity jointly control the organic matter enrichment of shallow water source rocks in the evaporite series. The degree of enrichment of organic matter in shallow water source rocks first increases and then decreases with the increase in paleosalinity. All the samples with high content of organic matter come from the shallower environment of the Awatag Fm.


Export Citation Format

Share Document