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Examines trends in the production of nonferrous metals in Kazakhstan during the 1990s. Overall importance of nonferrous metals within the Kazakh economy; Analysis of production of each of the important mineral commodities; Information on resource base, development of new infrastructure and projects involving international participation.

Examines the issue of whether member states of the International Tin Council (ITC) were secondarily or concurrently liable to third parties for the debts of the organization. Generally little difficulty in determining when international law governs a transaction; The ITC cases; Textual authorities; State practice; General principles of law; Conceptual considerations; Rationale for the ITC ruling; Conclusion.

The strongly acidic wastewater containing fluoride [F(-I)] is generally neutralized using lime, producing massive hazardous solid waste, which may present serious environmental risks. In this study, a novel precipitant, N,N′-Bis(3-(triethoxysilyl)propyl)thiourea, was developed for the selective removal of F(-I) from strongly acidic wastewater. The precipitant was synthesized using (3-aminopropyl)triethoxysilane and thiourea at a molar ratio of 2:1 under 160 ℃. More than 90% of initial F(-I) was removed by the prepared precipitant from strong acidic wastewater produced by nonferrous metal smelting industry, and the residual F(-I) concentration decreased to below 100 mg/L. The F(-I) removal performance is almost free from the interference of coexisting ions. Only 6 kg/m3 of fluoride slag, which can be recycled as a concrete waterproofing agent, was produced. The F(-I) removal mechanism including substitution, polycondensation, ion exchange and complexation was clarified: ‒OH on Si atoms in the hydrolysis product of BTPT was substituted by F(-I), and a fluoro-substituted product formed; the polycondensation of BTPT and fluoro-substituted product produced polymer precipitates; the specific adsorption of F(-I) on the polymer precipitates occurred through ion exchange with ‒OH and complexation with -NH 2 +-. ga1 • The precipitant selectively removes thousands of ppm F to below 100 mg/L. • The complexation of F(-I) with protonated imino group formed F-N species. • The substitution and exchange of oxhydryl on Si atom by F(-I) formed F-Si species. • The fluoride slag was reduced by 96% and it was recycled as waterproof agent. [ABSTRACT FROM AUTHOR]

In this paper, we comprehensively consider the environment and economic performance by employing non-radial distance function to study the regional eco-efficiency of China's Non-ferrous Metals Industry (NMI) during 2000–2016, from the perspective of total-factor through Data Envelopment Analysis (DEA)-Malmquist analysis framework. The change of regional technology gap ratio and the source of regional eco-inefficiency is also explored. Moreover, this paper analyzes the evolution of regional eco-efficiency and the main factors that contribute to changes in eco-efficiency. The results indicate that: First, the eco-efficiency of China's NMI has improved and has shown a certain degree of regional heterogeneity. Second, the main source of eco-inefficiency is management inefficiency in eastern China. The central, western and northeastern China all showed an increasing trend of technology gap inefficiency and a declining trend of management inefficiency during the sample period. Third, eastern China is regarded as a technology leader. The improvement of eco-efficiency in the central and northeastern China is mainly due to the promotion of technological progress, while the western region relies on the improvement of technical efficiency. The study suggests that strengthening scientific and technological research, promoting inter-regional technical exchanges are particularly important for eco-efficiency improvement and regional coordinated development in China's NMI. [ABSTRACT FROM AUTHOR]

• Average mercury isotopic signature in Chinese street dust was −0.61 ± 0.92 ‰ for δ202Hg and −0.03 ± 0.08 ‰ for Δ199Hg. • E-waste dust featuring positive δ202Hg (0.36 ± 0.63‰) and near-zero Δ199Hg (0.10 ± 0.02 ‰) was reported for the first time. • Mercury mining/smelting, nonferrous metal smelting, and coal-based industries resulted in hotspots of Hg contamination. • Street dust is an important THg exposure source for children in urban environments. Spatial distribution and isotope signature of mercury (Hg) in street dusts across China were investigated by collecting dust samples from 14 cities and reviewing previously published data from an additional 46 cities. Potential sources of street dust and the associated health risks to humans were also assessed. The total Hg (THg) concentrations in street dust ranged from 0.020–39.1 mg kg−1 with an average of 0.433 ± 0.185 mg kg−1 in the 60 cities. Street dust samples collected from 14 cities were characterized by slightly negative δ202Hg (−0.61 ± 0.92‰) and near-zero Δ199Hg (−0.03 ± 0.08‰) values, and coal combustion and industrial activities were estimated to be the major sources of Hg in street dust. The estimated average probable daily intake (PDI) of THg from street dust exposure for adults and children (1.36E–03 and 1.27E–02 μg d−1 kg−1, respectively) were comparable to their respective exposures via rice consumption in China. Children being exposed to THg in dust is a major concern in mercury mining areas (e.g., Wangshan and Xunyang), and may also be a concern in cities with major coal-based industries and nonferrous metal smelting. Results from this study suggest that exposure to street dust is not a primary MeHg exposure pathway in China. [ABSTRACT FROM AUTHOR]

• Li 2 CO 3 particles were prepared by thermally decomposing LiHCO 3 in a RPB reactor. • Ethanol was selected as the optimal dispersant during thermal decomposition. • The RPB enhances the heat transfer during the thermal decomposition. With the increasing demand for lithium battery, the use amount of Li 2 CO 3 has substantially increased, especially for the well-dispersed fine particles. However, preparing and reducing the size of battery-grade Li 2 CO 3 by the thermal decomposition method is still a challenge. In this work, a rotating packed bed (RPB) reactor was applied to prepare well-dispersed fine Li 2 CO 3 particles by thermal decomposition of LiHCO 3. Selection of dispersants in the thermal decomposition process was carried out as the first step and then ethanol was selected as the optimal dispersant, compared with polyethylene glycol (PEG) and polyvinyl alcohol (PVA). Effects of the volume fraction of dispersant, rotational speed, liquid flow rate, steam mass flow rate, and preheating temperature on the particle size were investigated. The median particle size (d 50) of Li 2 CO 3 product obtained in this study can meet the requirement of Chinese National Nonferrous Metal Industry Standard of battery-grade Li 2 CO 3 (YS/T582-2013) by adjusting the operation parameters appropriately, which displays the potential and considerable application prospects. [ABSTRACT FROM AUTHOR]

Examines the equipment and technology for recycling nonferrous metals. Classification of wastes based on the size and heat treatments administered to the surface in active gases and salts; Use of modern chemico-thermal and refining facilities; Recycling of nonferrous metal wastes at small plants only if an optimum processing system is established.