In this study, the average values of vertical velocity of particles emitted from an aluminum smelter in the surface layer of the atmosphere were estimated using a semi-empirical method. The method is ...based on regression analysis of the horizontal profile of pollutants measured along the selected direction using moss bioindicators. The selection of epiphytic mosses Sanionia uncinata was carried out in 2013 in the zone of influence of a metallurgical industry enterprise in the city of Kandalaksha, Murmansk region. The concentrations of As, Si, Ni, Zn, Ti, Cd, Na, Pb, Co, K, Ba, Ca, Mg, Mn, Sr, Fe, Al, V, Cr, Cu were determined using atomic emission spectrometry. The conducted assessments showed that the average particle velocity toward the Earth's surface, when considering large spatial and temporal scales, is tens of times higher than gravitational settling velocities.
PurposeThis study aims to identify the significant factors of the multi-dimpling process, determine the most influential parameters of multi-dimpling to increase the dimple sheet strength and make a ...low-cost model of the multi-dimpling for sheet metal industries. To create an empirical expression linking process performance to different input factors, the percentage contribution of these elements is also calculated.Design/methodology/approachTaguchi grey relational analysis is used to apply a new effective strategy to experimental data in order to optimize the dimpling process parameters while taking into account several performance factors and low-cost model. In addition, a statistical method called ANOVA is used to ensure that the results are adequate. The optimal process parameters that generate improved mechanical properties are determined via grey relational analysis (GRA). Every level of the process variables, a response table and a grey relational grade (GRG) has been established.FindingsThe factors created for experiment number 2 with 0.5 mm as the sheet thickness, 2 mm dimple diameter, 0.5 mm dimple depth, 8 mm dimples spacing and the material of SS 304 were allotted rank one, which belonged to the optimal parameter values giving the greatest value of GRG.Practical implicationsThe study demonstrates that the process parameters of any dimple sheet manufacturing industry can be optimized, and the effect of process parameters can be identified.Originality/valueThe proposed low-cost model is relatively economical and readily implementable to small- and large-scale industries using newly developed multi-dimpling multi-punch and die.
Price changes in the non-ferrous metal industry affect economic development, especially in resource-rich regions. However, the degree of price fluctuation differs among sectors in this industry. ...These differences would mislead policy makers on formulating policy about the long-term development of economic and industry. Existing studies do not present the whole feature picture regarding the effects of price changes in the non-ferrous metal industry. This paper analyzes the segmented effects of prices in the non-ferrous metal industry chain on economic development in Yunnan province, China. The effects caused by price changes in the mining, smelting, and processing sectors were studied using a static computable general equilibrium model with a looping algorithm to avoid omitting the key point of price. Furthermore, the relationships between sectors are discussed by categorizing the effects into crowding-out and pulling effects. Considering the situation of non-ferrous industry in China, the scenarios of price change between −30% and 30% in different sectors of the non-ferrous metal industry were developed. The results show that decreases in the smelting price benefit regional economic development and international trade. Price changes in the mid-stream smelting sector generate more pulling effects than changes in other sectors. This suggests that regional economic development can be promoted by adjusting the smelting price of non-ferrous metals in regions with abundant non-ferrous metal resources. Moreover, as price changes bring different crowding-out and pulling effects among sectors, new price-related policies should consider the effects on other sectors of the industry.
In this study, positive matrix factorization, multilinear engine 2, and geographic information systems were used to characterize the spatial-temporal patterns of sources for nine heavy metals in the ...surface sediments of the Yangtze River Estuary in different seasons. Results showed that six sources were identified: agricultural pesticide, marine transportation, chemical factory wastewater, metal smelter waste, atmospheric deposition, and agricultural fertilizer. The proportions of sources were similar during the entire year but varied among the seasons. The differences in the proportions of agricultural pesticide between winter and other seasons were greater than 12%. Over 40% of the Cd concentration in most seasons was attributed to atmospheric deposition, while less than 5% in autumn. The impact strength of most sources, except marine transportation and metal smelter waste, decreased from the inner regions to the adjacent sea. The difference in the impact strength of agricultural pesticide was the largest throughout the study area.
•Source apportionment and seasonal variation was analyzed with PMF and ME2.•Contents of metals were higher in autumn and winter than in spring and summer.•Proportions of sources were similar in a year, while varied largely among seasons.
Water is one of the basic necessities of life and having clean water is extremely important for human health. In recent years, β-cyclodextrin (β-CD)–based polymers and nanosystems have been ...extensively studied as adsorbents for the purpose of water purification. They present high efficiency and capability to remove inorganic, organic, and heavy metal impurities from wastewater as compared to conventional methods of water purification. β-CDs are cyclic polysaccharides having specific dimension of hydrophobic cavities and hydrophilic functional groups. The hydrophobic cavities form inclusion complexes through host–guest interactions. The hydroxyl groups form sites of hydrogen bonding and electrostatic interaction with pollutants. Additionally, they are also the sites of modification to bring about different derivatisation and polymerization reactions in order to impart desirable properties for efficient adsorption material. This article comprises of various derivatives of β-cyclodextrins: their nanoparticulate systems and their characterization and applications to remove different types of impurities from wastewater. The chemical reactions for their synthesis and mechanism of adsorption are highlighted.
This article presents a review of the main physical, chemical, electrochemical, and biological technologies used for treating heavy metals in the wastewater of industrial processes and in synthetic ...aqueous solutions which could be applied to leachate from landfills. This paper outlines the generalities, operating principles, and modifications made to the technologies described. It discusses and assesses which of these have better removal rates and higher levels of efficiency in minimizing the heavy metal concentrations contained in leachates, such as mercury, chromium, lead, nickel, and copper among others. The first part of the document presents the so-called conventional technologies, such as chemical, physical, and electrochemical treatment. These have been used to treat different wastewater, especially industrial waste, operating adequately from the technical topic, but with high costs and the secondary products’ production. The second part exposes biological treatments tend to be most widely used due to their versatility, effectiveness, and low cost, when compared with traditional technologies. It is important to note that there is no single treatment and that each of the technologies reviewed has different heavy metal decontamination rates. All technologies search to reduce concentrations of heavy metals to values that are safe for the natural resources where they are discharged or disposed, thereby complying with the regulatory limits regulated in each of the regions.
A new approach for the efficient and highly selective synthesis of 1,2‐amino alcohols by direct reductive hydrolysis of N‐formyl‐protected α‐amino nitriles is reported. The commercially available ...RuHCl(CO)(PPh3)3 complex was found to be a suitable catalyst for this operationally simple protocol, in which no stoichiometric amounts of undesired metal waste are generated. The deaminative hydrogenation is performed at 55 bar of H2, using a 6:1 mixture of 1,4‐dioxane/water as solvent. In addition, hydroxymethyl alcohols were prepared from cyanoketones under very similar conditions.
Keep it simple: A new protocol for the reductive hydrolysis of protected α‐amino nitriles using RuHCl(CO)(PPh3)3 complex as the catalyst has been developed to afford 1,2‐amino alcohols, in which no stoichiometric amounts of undesired metal waste are generated. This method is suitable for the preparation of industrially valuable compounds, such as 2‐amino‐2‐methyl propanol (AMP). In addition, hydroxymethyl alcohols can also be accessed from cyanoketones under analogous conditions.
The Ghanaian government aims to develop an integrated bauxite–aluminium industry and seeks to further bauxite extraction at several sites across the country. This vision is embedded within the ...political agenda “Ghana Beyond Aid,” introduced by the country's president, Nana Akufo‐Addo. One possible mining area is Atewa Forest, one of the few remaining intact upland evergreen rainforests in Ghana. This study highlights the important narratives local NGOs use to mobilise against bauxite mining at Atewa Forest: (a) the case of environmental justice with a strong focus on clean water and (b) the foreign Chinese influence. Both narratives have gained national as well as international attention. However, the government avoids direct discussion and legitimises extraction through the newly created political agenda Ghana Beyond Aid. The latter is better understood as a future‐making practice, a practice creating a single development path that only needs to be managed. At the same time, revenue from refined bauxite finances huge infrastructure projects that are the foundation of this political agenda. In addition, this legitimation to extract bauxite appears to be powerful because it is linked to broader global narratives about modernisation and economic growth.
Bauxite mining at Atewa Forest is linked with future promises about development that make the extraction appear as something achievable and without alternatives. Looking at “Ghana Beyond Aid” as a future‐making practice gives more attention to how the resource bauxite gains importance and its extraction gains legitimisation.
Purpose
The purpose of this study was to update the average environmental impacts of global primary zinc production using a life cycle assessment (LCA) approach. This study represents the latest ...contribution from zinc producers, which historically established the first life cycle inventory for primary zinc production in 1998 (Western Europe) and the first global LCA-based cradle-to-gate study for zinc concentrate and special high-grade zinc (SHG; 99.99 %) in 2009. Improvements from the previous studies were realized through expanded geographical scope and range of production technologies.
Methods
The product system under study (SHG zinc) was characterized by collecting primary data for the relevant production processes, including zinc ore mining and concentration, transportation of the zinc concentrate, and zinc concentrate smelting. This data was modeled in GaBi 6 and complemented with background data from the GaBi 2013 databases to create the cradle-to-gate LCA model. Allocation was used to distribute the inputs and outputs among the various co-products produced during the production process, with mass of metal content being the preferred allocation approach, when applicable.
Results and discussion
In total, this global study includes primary data from 24 mines and 18 smelters, which cover 4.7 × 10
6
MT of zinc concentrate and 3.4 × 10
6
MT of SHG zinc, representing 36 and 27 % of global production, respectively. While the LCA model generated a full life cycle inventory, selected impact categories and indicators are reported in this article (global warming potential, acidification potential, eutrophication potential, photochemical ozone creation potential, ozone creation potential, and primary energy demand). The results show that SHG zinc has a primary energy demand of 37,500 MJ/t and a climate change impact of 2600 kg CO
2
-eq./t. Across all impact categories and indicators reported here, around 65 % of the burden are associated with smelting, 30 % with mining and concentration, and 5 % with transportation of the concentrate. Sensitivity analyses were carried out for the allocation method (total mass versus mass of metal content) and transportation of zinc concentrate.
Conclusions
This study generated updated LCA information for the global production of SHG zinc, in line with the metal industry’s current harmonization efforts. Through the provision of unit process information for zinc concentrate and SHG zinc production, greater transparency is achieved. Technological and temporal representativeness was deemed to be high. Geographical representativeness, however, was found to be moderate to low. Future studies should focus on increasing company participation from underrepresented regions.
► Pyrolysis of plastic waste. ► Comparison of different samples: real waste, simulated and real waste+catalyst. ► Study of the effects of inorganic components in the pyrolysis products.
Pyrolysis may ...be an alternative for the reclamation of rejected streams of waste from sorting plants where packing and packaging plastic waste is separated and classified. These rejected streams consist of many different materials (e.g., polyethylene (PE), polypropylene (PP), polystyrene (PS), polyvinyl chloride (PVC), polyethylene terephthalate (PET), acrylonitrile butadiene styrene (ABS), aluminum, tetra-brik, and film) for which an attempt at complete separation is not technically possible or economically viable, and they are typically sent to landfills or incinerators. For this study, a simulated plastic mixture and a real waste sample from a sorting plant were pyrolyzed using a non-stirred semi-batch reactor. Red mud, a byproduct of the aluminum industry, was used as a catalyst. Despite the fact that the samples had a similar volume of material, there were noteworthy differences in the pyrolysis yields. The real waste sample resulted, after pyrolysis, in higher gas and solid yields and consequently produced less liquid. There were also significant differences noted in the compositions of the compared pyrolysis products.
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