scholarly journals Copper metallurgy at the crossroads

2007 ◽  
Vol 43 (1) ◽  
pp. 1-19 ◽  
Author(s):  
F. Habashi
Keyword(s):  
Sulfuric Acid ◽  
Elemental Sulfur ◽  
Copper Production ◽  
Pressure Leaching ◽  
Copper Industry ◽  
Hydrothermal Conditions ◽  
The Past ◽  
Copper Metallurgy ◽  
Horizontal Furnace ◽  
Sulfide Concentrates

Copper technology changed from the vertical to the horizontal furnace and from the roast reaction to converting towards the end of the last century. However, the horizontal furnace proved to be an inefficient and polluting reactor. As a result many attempts were made to replace it. In the past 50 years new successful melting processes were introduced on an industrial scale that were more energy efficient and less polluting. In addition, smelting and converting were conducted in a single reactor in which the concentrate was fed and the raw copper was produced. The standing problem in many countries, however, is marketing 3 tonnes of sulfuric acid per tonne of copper produced as well as emitting large amounts of excess SO2 in the atmosphere. Pressure hydrometallurgy offers the possibility of liberating the copper industry from SO2 problem. Heap leaching technology has become a gigantic operation. Combined with solvent extraction and electrowinning it contributes today to about 20% of copper production and is expected to grow. Pressure leaching offers the possibility of liberating the copper industry from SO2 problem. The technology is over hundred years old. It is applied for leaching a variety of ores and concentrates. Hydrothermal oxidation of sulfide concentrates has the enormous advantage of producing elemental sulfur, hence solving the SO2 and sulfuric acid problems found in smelters. Precipitation of metals such as nickel and cobalt under hydrothermal conditions has been used for over 50 years. It has the advantage of a compact plant but the disadvantage of producing ammonium sulfate as a co-product. In case of copper, however, precipitation takes place without the need of neutralizing the acid, which is a great advantage and could be an excellent substitute for electrowinning which is energy intensive and occupies extensive space. Recent advances in the engineering aspects of pressure equipment design open the door widely for increased application. .

Preparation of Thin Cadmium Telluride Samples for Electron Microscope Studies

1974 ◽  
Vol 32 ◽  
pp. 548-549
Author(s):  
T. J. Magee ◽  
J. Peng ◽  
J. Bean
Keyword(s):  
Electron Microscope ◽  
Sulfuric Acid ◽  
Solid State ◽  
Sample Preparation ◽  
Cadmium Telluride ◽  
Potassium Dichromate ◽  
Optical Components ◽  
The Past ◽  
Solid State Devices

Cadmium telluride has become increasingly important in a number of technological applications, particularly in the area of laser-optical components and solid state devices, Microstructural characterizations of the material have in the past been somewhat limited because of the lack of suitable sample preparation and thinning techniques. Utilizing a modified jet thinning apparatus and a potassium dichromate-sulfuric acid thinning solution, a procedure has now been developed for obtaining thin contamination-free samples for TEM examination.

scholarly journals Distinct Roles of Acidophiles in Complete Oxidation of High-Sulfur Ferric Leach Product of Zinc Sulfide Concentrate

2020 ◽  
Vol 8 (3) ◽  
pp. 386 ◽  
Author(s):  
Maxim Muravyov ◽  
Anna Panyushkina
Keyword(s):  
Microbial Community ◽  
Zinc Sulfide ◽  
Elemental Sulfur ◽  
Waste Product ◽  
Sulfur Oxidation ◽  
Low Grade ◽  
Sulfide Concentrates ◽  
Sulfide Concentrate ◽  
Elemental Sulfur Oxidation ◽  
Ferric Leaching

A two-step process, which involved ferric leaching with biologically generated solution and subsequent biooxidation with the microbial community, has been previously proposed for the processing of low-grade zinc sulfide concentrates. In this study, we carried out the process of complete biological oxidation of the product of ferric leaching of the zinc concentrate, which contained 9% of sphalerite, 5% of chalcopyrite, and 29.7% of elemental sulfur. After 21 days of biooxidation at 40 °C, sphalerite and chalcopyrite oxidation reached 99 and 69%, respectively, while the level of elemental sulfur oxidation was 97%. The biooxidation residue could be considered a waste product that is inert under aerobic conditions. The results of this study showed that zinc sulfide concentrate processing using a two-step treatment is efficient and promising. The microbial community, which developed during biooxidation, was dominated by Acidithiobacillus caldus, Leptospirillum ferriphilum, Ferroplasma acidiphilum, Sulfobacillus thermotolerans, S. thermosulfidooxidans, and Cuniculiplasma sp. At the same time, F. acidiphilum and A. caldus played crucial roles in the oxidation of sulfide minerals and elemental sulfur, respectively. The addition of L. ferriphilum to A. caldus during biooxidation of the ferric leach product proved to inhibit elemental sulfur oxidation.

Alpine sparsely vegetated areas in the eastern Qilian Mountains shrank with climate warming in the past 30 years

2018 ◽  
Vol 42 (4) ◽  
pp. 415-430 ◽  
Author(s):  
Biao Zeng ◽  
Fuguang Zhang ◽  
Taibao Yang ◽  
Jiaguo Qi ◽  
Mihretab G Ghebrezgabher
Keyword(s):  
Climate Change ◽  
Climate Warming ◽  
Vegetation Index ◽  
Normalized Difference Vegetation Index ◽  
Regional Scale ◽  
Qilian Mountains ◽  
Visual Interpretation ◽  
Hydrothermal Conditions ◽  
The Past ◽  
Distribution Ranges

Alpine sparsely vegetated areas (ASVAs) in mountains are sensitive to climate change and rarely studied. In this study, we focused on the response of ASVA distribution to climate change in the eastern Qilian Mountains (EQLM) from the 1990s to the 2010s. The ASVA distribution ranges in the EQLM during the past three decades were obtained from the Thematic Mapper remote sensing digital images by using the threshold of normalized difference vegetation index (NDVI) and artificial visual interpretation. Results indicated that the ASVA shrank gradually in the EQLM and lost its area by approximately 11.4% from the 1990s to the 2010s. The shrunken ASVA with markedly more area than the expanded one was mainly located at altitudes from 3700 m to 4300 m, which were comparatively lower than the average altitude of the ASVA distribution ranges. This condition led to the low ASVA boundaries in the EQLM moving upwards at a significant velocity of 22 m/decade at the regional scale. This vertical zonal process was modulated by topography-induced differences in local hydrothermal conditions. Thus, the ASVA shrank mainly in its lower parts with mild and sunny slopes. Annual maximum NDVI in the transition zone increased significantly and showed a stronger positive correlation with significantly increasing temperature than insignificant precipitation variations during 1990–2015. The ASVA shrinkage and up-shifting of its boundary were attributed to climate warming, which facilitated the upper part of alpine meadow in the EQLM by releasing the low temperature limitation on vegetation growth.

Luminescence Intensity Enhancement of Copper Doped Hydronium Alunite Synthesized under Hydrothermal Conditions Using Sulfates Solution

2014 ◽  
Vol 90 ◽  
pp. 127-132
Author(s):  
Yuichiro Kuroki ◽  
Takashi Hatsuse ◽  
Tomoichiro Okamoto ◽  
Masasuke Takata
Keyword(s):  
Crystal Structure ◽  
Luminescence Intensity ◽  
Single Phase ◽  
Elemental Sulfur ◽  
Nitrate Solution ◽  
Hydrothermal Condition ◽  
Copper Nitrate ◽  
Hydrothermal Conditions ◽  
Photoluminescence Peak ◽  
Blue Photoluminescence

A novel phosphor, copper doped hydronium alunite ((H3O)Al3(SO4)2(OH)6:Cu), exhibiting a blue photoluminescence peak at a wavelength of 420 nm was successfully synthesized from aluminum and copper sulfates solution under hydrothermal condition (240 °C, 60 min). The measurement of XRD revealed that the obtained products were single phase with a crystal structure of (H3O)Al3(SO4)2(OH)6. Luminescence intensity of (H3O)Al3(SO4)2(OH)6:Cu synthesized from sulfates solution was 6.2 times higher than that from an aluminum nitrate solution mixed with an elemental sulfur and a copper nitrate solution. The increase of luminescence intensity was resulted from an improvement of the crystallinity of (H3O)Al3(SO4)2(OH)6.

scholarly journals Integrating Digital Datasets into Public Engagement through ArcGIS StoryMaps

2020 ◽  
Vol 8 (4) ◽  
pp. 351-360
Author(s):  
Matthew D. Howland ◽  
Brady Liss ◽  
Thomas E. Levy ◽  
Mohammad Najjar
Keyword(s):  
Iron Age ◽  
Public Engagement ◽  
Three Dimensional ◽  
First Century ◽  
Copper Production ◽  
The Public ◽  
The Past ◽  
Archaeological Methods ◽  
Three Dimensional Models

AbstractArchaeologists have a responsibility to use their research to engage people and provide opportunities for the public to interact with cultural heritage and interpret it on their own terms. This can be done through hypermedia and deep mapping as approaches to public archaeology. In twenty-first-century archaeology, scholars can rely on vastly improved technologies to aid them in these efforts toward public engagement, including digital photography, geographic information systems, and three-dimensional models. These technologies, even when collected for analysis or documentation, can be valuable tools for educating and involving the public with archaeological methods and how these methods help archaeologists learn about the past. Ultimately, academic storytelling can benefit from making archaeological results and methods accessible and engaging for stakeholders and the general public. ArcGIS StoryMaps is an effective tool for integrating digital datasets into an accessible framework that is suitable for interactive public engagement. This article describes the benefits of using ArcGIS StoryMaps for hypermedia and deep mapping–based public engagement using the story of copper production in Iron Age Faynan, Jordan, as a case study.

scholarly journals Arsenic in Chemical and Metallurgical Conversions of Copper-zinc Concentrates

2020 ◽  
Author(s):  
Evgeny Nikolaevich Selivanov ◽  
Dmitry Olegovich Novikov ◽  
Vyacheslav Vasi- Lyevich Belyaev ◽  
Gennady Veniaminovich Skopov
Keyword(s):  
Sulfuric Acid ◽  
Electrostatic Precipitator ◽  
Metallic Copper ◽  
Gas Treatment ◽  
Sulfuric Acid Production ◽  
Keywords Arsenic ◽  
Copper Zinc ◽  
Sulfide Concentrates ◽  
Impurity Elements

Due to the deterioration of the quality of obtained sulfide-copper concentrates, arsenic circulates and accumulates in the intermediate products, which reduces the quality of the metal and associated product – sulfuric acid. A method of estimation the distribution of impurity elements can be created using the recycling of sulfide concentrates by various technologies (including autogenous smelting, matte conversion and flotation of slags). This technique is based on solving balance equations for iron, copper and arsenic with known compositions of the resulting products. The obtained data were used to assess of the extraction of arsenic into produce outputs (slag, matte, dust, etc.). In this study, the concentration of arsenic in the dust of metallurgical processes and sludge for cleaning acid solutions is confirmed. The increased temperature in the electrostatic precipitator of gas purification of autogenous processes lead to a partial transition of arsenic into the gas stream directed to the sulfuric acid production. It is possible to regulate the fraction of transition of arsenic to dust and sulfuric acid while changing the operating temperature in the electrostatic precipitator. To a lesser extent arsenic is concentrated in the tails of flotation of slag (11.7%) and metallic copper (2.9%). These data are useful for substantiating measures for the wastes recycling and improvement of the ecological environment in the enterprise operating districts. Keywords: arsenic, autogenous melting, matte conversion, slag flotation, purified gas treatment, distribution, dust, sludge

scholarly journals Nitrogen mineralization and microbial activity as influenced by sulfur sources in an alkaline calcareous soil

1970 ◽  
pp. 14-18
Author(s):  
Tufail Shah ◽  
Zahir Shah ◽  
Syed Atizaz Ali Shah ◽  
Nazir Ahmad
Keyword(s):  
Organic Matter ◽  
Sulfuric Acid ◽  
Microbial Activity ◽  
Calcareous Soil ◽  
Bacterial Population ◽  
Elemental Sulfur ◽  
Microbial Population ◽  
Organic Matter Content ◽  
Matter Content ◽  
Fungal Population

A study was performed to check the effects of various sources of sulfur on microbial activity, microbial population, N mineralization and organic matter content in an alkaline calcareous soil by using soil samples collected from Malakandher Farm at 0-20 cm depth, and analyzed for microbial activity, total mineral nitrogen, bacterial and fungal population and organic matter content. The results showed that the rate of CO2 evolution and cumulative CO2 production were higher in soils amended with elemental sulfur followed by sulfuric acid and gypsum treated soils. The microbial activity decreased with incubation period in all treatments, and the microbial population was greatly affected by sulfur sources. Generally, the bacterial population decreased in soils amended with elemental sulfur, but the population was higher in soils amended with gypsum. Bacterial population was suppressed in soils treated with sulfuric acid. However, the fungal population was higher in soils amended with sulfuric acids was less in soil amended with elemental sulfur. The sulfur amendments promoted immobilization of N. The net N immobilized was higher in soil amended with gypsum followed by soils amended with sulfuric acid and elemental sulfur. The percent organic matter was higher in soils amended with gypsum and was decreased compared with that amended with elemental sulfur or sulfuric acid. These results suggested that soil microbiological properties changed with sulfur amendments during laboratory incubation.

Beneficiation of titania by sulfuric acid pressure leaching of Panzhihua ilmenite

2014 ◽  
Vol 150 ◽  
pp. 92-98 ◽  
Author(s):  
Linie Jia ◽  
Bin Liang ◽  
Li Lü ◽  
Shaojun Yuan ◽  
Lijuan Zheng ◽  
...  
Keyword(s):  
Sulfuric Acid ◽  
Pressure Leaching
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