Hasil untuk "Mineral industries. Metal trade"

A. Nazari, Rebecca Radzinski, A. Ghahreman

A. R. Circuncisão, Marcelo D. Catarino, S. Cardoso et al.

Seaweeds are well-known for their exceptional capacity to accumulate essential minerals and trace elements needed for human nutrition, although their levels are commonly very variable depending on their morphological features, environmental conditions, and geographic location. Despite this variability, accumulation of Mg, and especially Fe, seems to be prevalent in Chlorophyta, while Rhodophyta and Phaeophyta accumulate higher concentrations of Mn and I, respectively. Both red and brown seaweeds also tend to accumulate higher concentrations of Na, K, and Zn than green seaweeds. Their valuable mineral content grants them great potential for application in the food industry as new ingredients for the development of numerous functional food products. Indeed, many studies have already shown that seaweeds can be used as NaCl replacers in common foods while increasing their content in elements that are oftentimes deficient in European population. In turn, high concentrations of some elements, such as I, need to be carefully addressed when evaluating seaweed consumption, since excessive intake of this element was proven to have negative impacts on health. In this regard, studies point out that although very bioaccessible, I bioavailability seems to be low, contrarily to other elements, such as Na, K, and Fe. Another weakness of seaweed consumption is their capacity to accumulate several toxic metals, which can pose some health risks. Therefore, considering the current great expansion of seaweed consumption by the Western population, specific regulations on this subject should be laid down. This review presents an overview of the mineral content of prevalent edible European macroalgae, highlighting the main factors interfering in their accumulation. Furthermore, the impact of using these marine vegetables as functional ingredients or NaCl replacers in foods will be discussed. Finally, the relationship between macroalgae’s toxic metals content and the lack of European legislation to regulate them will be addressed.

Yue‐Jun Zhang, Wei Shi, Lin-Kui Jiang

China's carbon emissions trading (CET) policy aims to force relevant enterprises to implement low‐carbon technology innovation and address environmental challenges through marketization means. However, how China's CET policy may affect enterprise technology innovation and whether this effect may differ in industries remain to be further investigated. Therefore, based on the panel data of listed enterprises covered by the CET policy in China during 2009–2017, this paper employs the difference‐in‐difference (DID) and DID‐based propensity score matching models to evaluate the effect of CET on technology innovation. The empirical results indicate that the effect of China's CET on the technology innovation of related enterprises is generally not significant during the sample period, but this effect presents evident industrial heterogeneity. Specifically, among the eight CET‐covered industries, the CET policy helps to improve technology innovation for power and aviation enterprises but not in the other six industries (i.e., steel, chemical, building material, petrochemical, nonferrous metals, and paper), which implies that China's CET policy still has great potential for promoting the technology innovation of related enterprises. In addition, the central findings remain robust when the system generalized method of moment and DID‐based coarsened exact matching models are applied to consider the influence of omitted variables, unobservable confounders, and different matching methods.

C. Beard, K. Goodenough, A. Borst et al.

Nickolay Rulyov

Flotation of small particles is one of the global challenges facing the mineral raw materials processing industry. Large amounts of non-ferrous and rare metals are lost in the flotation tailings in the form of mineral particles below 15 µm in size as a result of the low effectiveness of their capture by coarse bubbles generated in conventional flotation machines. The method of combined microflotation, developed in recent years, uses conventional coarse bubbles (CB) and microbubbles (MB) produced in the stand-alone generator of air-in-water microdispersion, which serves as the flotation carriers. Depending on the MB dose, the effect of their application may be positive or negative. The theoretical analysis of various mechanisms of particle transfer onto the surface of coarse bubbles and further into the froth layer allowed to obtain the formula for the optimal MB dose f=dd/2dprp, where dd is MB size; dp and rp respectively are the size and the density of particles. Experiments performed on the copper ore flotation tailings at the Atalaya Mining (Spain) and Chaarat Kapan (Armenia) concentrators showed that, besides the optimal MB dose in the range of 1-3 ml/g, there is another optimal MB dose in the range of 10-20 ml/g, where the copper recovery increases by several percent compared to the reference test (f = 0). The deep minimum in copper recovery is observed in the area between the optimal MB doses, which is by several percent lower than the value in the reference test.

K. K. Brar, Sara Magdouli, Selma Etteieb et al.

Abstract The recovery of copper from secondary waste resources (e.g. electronic wastes, slag, fly-ash, sludge and spent catalysts) via oxidative and reductive bioleaching becomes a running trend and a potential alternative to limited metal supply. The motive of this review is to ponder over recycling of secondary waste towards the circular economy to reduce environmental risks as well as to increase the economic profitability of the mining industry. The biochemistry of iron/sulfur minerals, bacteria–mineral interactions and adaptive behavior allowing the acidophiles to survive are among the key parameters to be optimized during the bio recovery of copper. The use of OMICS approaches such as genomics, proteomics, transcriptomics and metabolomics is also crucial to elucidate a comprehensive view of the bioleaching communities, their mechanisms and interactions with minerals. This handy information can act as a boon to develop potential strains by adopting synthetic biology and antiviral CRISPR-Cas9 technologies to efficiently control the bioleaching process. Furthermore, some of these recent discoveries to design bioelectrochemical system (BES) and to achieve higher rate of metal recovery are discussed. Finally, the objective of this study is to narrow the gap between fundamental and applied research to fully address scientific, technological and economic challenges and bottlenecks of bioleaching process in general and BES in particular.

A. Ahmad

Exporting and importing develops national economies and grows the worldwide market. Each nation is supplied with specific features in resources and skills. For instance, a few nations are wealthy in common assets, for example, petroleum derivatives, timber, fruitful soil or valuable metals and minerals, while different nations have deficiencies of a considerable lot of these assets. Furthermore, a few nations have profoundly evolved frameworks, instructive frameworks and capital markets that license them to participate in complex assembling and mechanical advancements, while numerous nations don't. Imports are significant for organizations and individual customers [1] . Nations like Ellen's frequently need to import products that are either not promptly accessible locally or are accessible less expensive abroad. Singular customers likewise advantage from the privately delivered items with imported parts just as different items that are brought into the nation. As a rule, imported items give a superior cost or more decisions to purchasers, which helps increment their way of life.

D. P. Mohapatra, D. Kirpalani

D. R. Leal-Ayala, J. Allwood, E. Petavratzi et al.

Tungsten is an economically important metal with diverse applications ranging from wear resistant cutting tools to its use in specialized steels and alloys. Concerns about its supply security have been raised by various studies in literature, mostly due to trade disputes arising from supply concentration and exports restrictions in China and its lack of viable substitutes. Although tungsten material flows have been analysed for specific regions, a global mass flow analysis of tungsten is still missing in literature and its global supply chain remains opaque for industry outsiders. The objective of this paper is to create a map of global tungsten flows to highlight and discuss key material efficiency (i.e., using less of a material to make a product or supply a service, or reducing the material entering production but ending up in waste) and supply security opportunities along tungsten’s supply chain that could be incorporated into the planning and prioritization of future supply security strategies. The results indicate the existence of various intervention alternatives that could help to broaden the supply base and improve the overall material efficiency of the system. In particular, future policy and research and development (R&D) efforts to improve tungsten’s material efficiency should focus on minimizing tungsten losses as fine particles during beneficiation and extraction (current global losses estimated at 10–40%), as well as on evaluating alternatives to improve recycling collection systems and technologies, which could lead to 17–45% more tungsten discards being recycled into new products.

Zhu Liu

China has become the world’s largest carbon emitter. Its total carbon emission output from fossil fuel combustion and cement production was approximately 10 Gt CO_2 in 2013. However, less is known about carbon emissions from the production of industrial materials, such as mineral products (e.g., lime, soda ash, asphalt roofing), chemical products (e.g., ammonia, nitric acid) and metal products (e.g., iron, steel and aluminum). Carbon emissions from the production processes of these industrial products (in addition to cement production) are also less frequently reported by current international carbon emission datasets. Here we estimated the carbon emissions resulting from the manufacturing of 5 major industrial products in China, given China’s dominant position in industrial production in the world. Based on an investigation of China’s specific production processes, we devised a methodology for calculating emission factors. The results indicate that China’s total carbon emission from the production of alumina, plate glass, soda ash, ammonia and calcium carbide was 233 million tons in 2013, equivalent to the total CO_2 emissions of Spain in 2013. The cumulative emissions from the manufacturing of these 5 products during the period 1990–2013 was approximately 2.5 Gt CO_2, more than the annual total CO_2 emissions of India. Thus, quantifying the emissions from industrial processes is critical for understanding the global carbon budget and developing a suitable climate policy.

A. Boulamanti, J. Moya

Our study compares production costs of the non-ferrous metals (NFM) industry in the European Union (EU) and other countries in order to understand whether these costs are higher in Europe. Our analysis focuses on copper and zinc, since they are considered to be the most greatly consumed non-ferrous metals after aluminium. The countries selected for comparison depend on the metal and are based on high shares of extra-EU28 trade and/or of global installed capacity. A bottom-up approach has been followed, based on information at facility level for primary production of the two metals. The analysis includes 32 copper smelters, 34 copper refineries and 23 zinc smelters, representing 72%, 58% and 30% of global production of copper anodes, cathodes and zinc slab respectively. Taking into consideration the complex structure of the industry, costs are broken down to three components: (1) Energy, (2) Labour and other costs (salaries, consumables and other on-site costs) and (3) Credits (due to co-products). Our findings suggest that although interesting observations emerge in each of these components, overall costs compare more favourably among countries than initially thought. The EU industry does not have the highest production costs. On the contrary, especially in the case of copper refineries and zinc, it has lower production costs than most of the countries included in the study.

D. Roberts, R. de Nys, N. Paul

The energy, mining and mineral processing industries are point sources of metal-contaminated waste water and carbon dioxide (CO2). Freshwater macroalgae from the genus Oedogonium can be grown in metal-contaminated waste water to generate biomass for bioenergy applications and concomitantly bioremediate metals. However, interactions between CO2 addition and algal growth, which can affect bioremediation, remain untested. The addition of CO2 to algal cultures in the Ash Dam Water (ADW) from a coal-fired power station increased the biomass productivity of Oedogonium sp. from 6.8 g dry weight (DW) m-2 d-1 to a maximum of 22.5 g DW m-2 d-1. The greater productivity increased the rate of bioremediation of most elements. However, over time carbon-amended cultures experienced a decline in productivity. Possible explanations include metal toxicity at low pH or essential trace element limitation as a result of competition between toxic and essential trace elements for uptake into algae. Higher productivity increased bioremediation rate and yielded more biomass for bioenergy applications, making maintenance of maximum productivity the central aim of the integrated culture model. To do so it will be necessary to resolve the mechanisms responsible for declining yields over time in carbon-amended cultures. Regardless, our data demonstrate that freshwater macroalgae are ideal candidates for bioremediation of metal-contaminated waste streams. Algal culture delivered significant improvement in ADW quality, reducing 5 elements that were initially in excess of water quality criteria (Al, As, Cd, Ni and Zn) to meet guidelines within two to four weeks.

D. Humphreys

E. Fisher, John Childs

Ibraheem Tarawneh, M. Lampl, D. Robins et al.

Work-related musculoskeletal disorders (WMSDs) resulting from ergonomic hazards are common in the United States. Recent data from the Bureau of Labor Statistics (BLS) indicate that in 2011, one third of occupational injuries and illnesses resulting in lost time from work were WMSDs. Based on data from the 2010 BLS Survey of Occupational Injuries and Illnesses, a higher rate of WMSDs resulting in lost time from work occurred in the Wholesale and Retail Trade (WRT) industry compared with most other industries. To assess trends and identify WRT subsectors and subgroups associated with high rates of WMSD workers' compensation claims, the Ohio Bureau of Workers' Compensation (OBWC) and CDC analyzed OBWC claims data for single-location WRT employers in Ohio for the period 2005-2009. From 2005 to 2009, the rate of WMSD claims declined from 86.3 to 52.8 per 10,000 employees. The three WRT industry subsectors with the highest rates of WMSD claims were Merchant Wholesalers, Nondurable Goods; Furniture and Home Furnishings Stores; and Merchant Wholesalers, Durable Goods. Within those three WRT subsectors, the highest rates of WMSD claims were noted in five subgroups: furniture stores and wholesalers of alcoholic beverages, groceries and related products, metal and minerals, and motor vehicle parts. Providing recommendations for WMSD prevention is particularly important for these WRT subgroups.

M. E. López-Mosquera, C. Moirón, E. Carral

L. Welch, Elizabeth Haile, J. Dement et al.

A. Zouboulis, K. A. Matis

M. Prasad