Changing the conventional clarification method in metal sulfide precipitation by a membrane-based filtration process

Nonmagmatic, carbonate-hosted epigenetic hydrothermal Pb–Zn deposits similar to those at the Huize Pb–Zn Mine are widespread across the Sichuan–Yunnan–Guizhou (SYG) polymetallic province. The precipitation mechanisms of these geologically intriguing deposits are an area of interest for many researchers. To simulate the underlying precipitation reaction mechanisms and dynamics of each aspect, a fluid mixing model for metal sulfide precipitation was used in a series of experiments, where solutions that contain Pb/Zn chloride complexes and sulfide were subjected to pH changes, water-rock reactions, and dilutions. Based on the results of these experiments, thermodynamic phase diagrams, and other experimental findings, a fluid mixing genetic model was developed for SYG Pb–Zn deposits, and this model was used to analyze the mechanisms of metal sulfide precipitation. The results indicate that acidic fluids in the form of chloride complexes transported Pb and Zn, whereas sulfide exists in the form of H2S within these fluids. The precipitation of metal sulfides occurs when these fluids undergo changes in pH, water-rock reactions, or isothermal dilution. The pH changes were found to be the most effective method for the induction of sulfide precipitation, followed by dilution and then water-rock reactions. The formation of sulfide precipitates due to pH changes, water-rock reactions, and dilution can be attributed to a single mechanism, i.e., changes in the pH of the fluid. Therefore, changes in pH are the primary mechanism of sulfide precipitation.

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Metal Sulfide Precipitation: Recent Breakthroughs and Future Outlooks

Minerals ◽

10.3390/min11121385 ◽

2021 ◽

Vol 11 (12) ◽

pp. 1385

Author(s):

Humberto Estay ◽

Lorena Barros ◽

Elizabeth Troncoso

Keyword(s):

Membrane Filtration ◽

Metal Sulfide ◽

Flow Diagram ◽

Research Approach ◽

Liquid Separation ◽

Direct Production ◽

Unit Operations ◽

Sulfide Precipitation ◽

Solid Liquid ◽

Solid Liquid Separation

The interest in metal sulfide precipitation has recently increased given its capacity to efficiently recover several metals and metalloids from different aqueous sources, including wastewaters and hydrometallurgical solutions. This article reviews recent studies about metal sulfide precipitation, considering that the most relevant review article on the topic was published in 2010. Thus, our review emphasizes and focuses on the overall process and its main unit operations. This study follows the flow diagram definition, discussing the recent progress in the application of this process on different aqueous matrices to recover/remove diverse metals/metalloids from them, in addition to kinetic reaction and reactor types, different sulfide sources, precipitate behavior, improvements in solid–liquid separation, and future perspectives. The features included in this review are: operational conditions in terms of pH and Eh to perform a selective recovery of different metals contained in an aqueous source, the aggregation/colloidal behavior of precipitates, new materials for controlling sulfide release, and novel solid–liquid separation processes based on membrane filtration. It is therefore relevant that the direct production of nanoparticles (Nps) from this method could potentially become a future research approach with important implications on unit operations, which could possibly expand to several applications.

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Base Metal Sulfide Deposits in Sedimentary and Volcanic Environments

10.1007/978-3-662-02538-3 ◽

1988 ◽

Keyword(s):

Base Metal ◽

Metal Sulfide ◽

Base Metal Sulfide ◽

Sulfide Deposits

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Native Metal Sulfide Mineralization of Perga Ore Knot (the Ukrainian Shield)

Mineralogical Journal ◽

10.15407/mineraljournal.39.04.077 ◽

2017 ◽

Vol 39 (4) ◽

pp. 77-88

Author(s):

B. SLOBODYAN ◽

V. PAVLYSHYN ◽

S. BONDARENKO ◽

L. STEPANYUK ◽

V. SYOMKA ◽

...

Keyword(s):

Metal Sulfide ◽

Ukrainian Shield ◽

Sulfide Mineralization ◽

Native Metal

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METHODS AND ALGORITHMS FOR THE COMPLETE PROCESSING OF A POSTDETECTOR LOW-CONTRAST OPTICAL IMAGE

Issues of radio electronics ◽

10.21778/2218-5453-2018-3-99-107 ◽

2018 ◽

pp. 99-107

Author(s):

V. V. Lavrov ◽

R. S. Luchkin ◽

O. I. Nemykin ◽

M. E. Prokhorov ◽

Yu. G. Ryndin ◽

...

Keyword(s):

Optical Image ◽

Structural Elements ◽

Filtration Process ◽

Low Contrast ◽

Information Object ◽

Detection Stage ◽

Metric Structures ◽

Spot 5 ◽

Integrated Indicators ◽

Complete Processing

Methods and algorithms for the complete processing of a post-detector low-contrast optical image (OI) of an unknown remote object obtained by ground-based optical means of observation under conditions of a complex background situation are considered. The purpose of processing is to separate and interpret at least with the help of the analyst, of the main constructive elements using the integrated indicators introduced in [6] and the characteristics of the analyzed OI, which are connected by the information, topological and metric structures of the OI. The stages of processing the OI include extracting the image-containing information object of the image portion (detection) and filtration of the OI, using recursive rank filtering. The final stages of processing include the segmentation of the OI and the allocation on it constructive elements using the apparatus of graph theory. An example of image processing of a Spot-5 spacecraft obtained in real conditions is given. It is shown that in this case at the detection stage it is possible to reduce the volume of information processed at subsequent stages by 8 times, in the filtration process to increase the compactness of the OI and to increase its connectivity in comparison with the post-detection OI. As a result of segmentation and allocation of constructive elements, three structural elements that can be interpreted as a spacecraft case and two remote panels can be identified with the analyst’s participation.

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Preparation and photocatalytic performance of metallic Nb0.9Ta0.1S2/2D-C3N4 composite

Oxford Open Materials Science ◽

10.1093/oxfmat/itab005 ◽

2020 ◽

Vol 1 (1) ◽

Author(s):

Hanxiang Chen ◽

Jianjian Yi ◽

Zhao Mo ◽

Yanhua Song ◽

Wenshu Yang ◽

...

Keyword(s):

Separation Efficiency ◽

Low Cost ◽

Metal Sulfide ◽

Electron Hole ◽

Practical Applications ◽

Energy And Environment ◽

Photocatalytic Application ◽

Light Utilization ◽

Ternary Metal ◽

Key Issues

Abstract Photocatalysis technology has potential application in the field of energy and environment. How to expand visible light utilization and promote the separation efficiency of the carriers are the key issues for the high active photocatalysts preparation and future practical applications. In this work, a ternary metal sulfide Nb0.9Ta0.1S2 was prepared and used as an electron collector in the photocatalytic application. As a result, the generated electrons are quickly transferred to the surface of the composite to participate in the reaction. It was demonstrated that the photocatalytic activity of 2D-C3N4 was enhanced after the modification of Nb0.9Ta0.1S2. The Nb0.9Ta0.1S2/2D-C3N4 composite material was synthesized by solvothermal method. The composition of 5% Nb0.9Ta0.1S2/2D-C3N4 showed the highest H2 evolution rate of 1961.6 μmolg−1h−1, which was 6.6 times that of 2D-C3N4. The 15% Nb0.9Ta0.1S2/2D-C3N4 exhibited the best activity in Rhodamine B degradation rate of 97% in 2 h, which is 50% higher than that of 2D-C3N4. Nb0.9Ta0.1S2/2D-C3N4 can be used as electron trap to promote the effective separation of electron–hole pairs. This work provides benchmarks in exploring low-cost and efficient cocatalyst.

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