汞污染已成为一个全球性的环境问题,我国是世界上大气汞排放量最大的国家,在批准《关于汞的水俣公约》之后,我国的汞污染控制面临严峻的挑战.燃煤部门是我国大气汞排放的第一大部门,也是履约的重点部门.本研究建立了我国燃煤部门2010年和2012年的大气汞排放清单,评估了“大气污染防治行动计划”(“大气十条”)对燃煤部门大气汞排放的协同控制效果.同时,使用情景分析法,对2020年和2030年燃煤部门的大气汞排放进行了预测,分析了未来不同控制措施的减排效果.结果表明,2010年中国燃煤电厂、燃煤工业锅炉和民用燃煤炉灶的大气汞排放量的最佳估计值分别为100.0、72.5和18.0 t.“大气十条”的实施可使我国燃煤部门到2017年比2012年减少92.5 t的大气汞排放.能源结构的调整、洗煤比例的提高和除尘设备的升级改造对于大气汞的减排效果最显著.在最佳估计情景下,2020年和2030年燃煤部门大气汞排放量分别为128.5和80.0t,与2010年相比分别降低了33％和58％;在最严格控制情景下,2020年和2030年燃煤部门大气汞的排放量分别为103.2和50.9t,相较2010年分别下降了46％和73％.

Mercury (Hg) pollution control has become an urgent need at global and national scales. This study, for the first time, comprehensively examines Hg flows in Mainland China and uncovers domestic and external causal drivers of China's Hg emissions/releases. Results show that China's Hg input reaches 2643 t in 2010. China discharges 1368 t of Hg to the environment (to air, 633 t; water, 84 t; and land, 651 t). Embedded Hg transfers across production sectors via waste/byproduct flows reduce Hg releases to land, but lead to secondary Hg emissions to air. Such revelations of embedded Hg transfers adjusts China's comprehensive Hg control that would otherwise only tackle primary emitters. Domestic consumption causes 67% of China's Hg emissions/releases, and external consumption induces the remaining 33%. Besides traditional production-side Hg control measures, demand-side measures and international joint efforts are required to effectively combat Hg pollution. Uncovering embedded and embodied Hg flows within the global economy can assist a paradigm shift necessary to make real progress in global Hg control and the implementation of the Minamata Convention on Mercury.

Waste acid is the dominant Hg-containing byproduct of nonferrous metals production processes.The mercury pollution control during the waste acid disposal processes directly impacts aquatic mercury release.This study conducted a mercury flow investigation in the waste acid disposal processes of six nonferrous metal smelters.Our study found that mercury concentrations in the waste acid were in the range of 0.3 to 90 μg · mL-1.The mercury concentrations in the waste acid slags were from 73 to 26 354 μg · g-1.The mercury concentrations in the sulfide slag of zinc smelter 1 and copper smelter 1 were 404 218 μg · g-1 and 10 972 μg · g-1, respectively.In generaly, mercury concentrations in the desulfurization slags were much lower than those in the waste acid slag and the sulfide slag.During the waste acid disposal processes, most mercury was released to the above slags.The mercury removal efficiencies during the waste acid disposal processes ranged from 72.9％ to 99.9％.Compared to the lime neutralization method and the lime iron salt method, the vulcanization method removed mercury from low-mercury waste acid more stably.Mercury concentrations in the discharge water samples ranged from 0.006 to 0.065 μg · mL-1, some of which exceeded the emission standards.

Gold production has been identified as an important source of anthropogenic mercury emissions. Few measurements have been conducted on the mercury emission in the industrial gold production. In this study, field measurements on mercury concentration and speciation profile in the roasting flue gas were conducted in a two-stage roasting gold smelter, and the corresponding mercury emission factors were obtained using mass balance analysis. The average mercury concentration in the feed gold concentrates was 730.0μg/kg, and the daily input mercury was 94.9g in this research. In the roasting procedure, 38.4%, 27.3% and 9.0% of input mercury was removed into the sulfuric acid, contaminated water and arsenic, respectively, while 22.8% of input mercury flowed into the cyanidation-refining procedure within the roasting residue and the dust collected from the gas cooling tower and the electrostatic precipitator. Finally, 2.3% and 5.9% of input mercury was emitted into the atmosphere with the roasting flue gas and the refining flue gas. Mercury concentration in the roasting flue gas was 4.02μg/m3, where the proportion of Hgp:Hg2+:Hg0 was 11:57:33. The balance calculation results indicated that the atmospheric mercury emission factor was 2.27×10−3gmercury/g gold produced for the tested smelter. Both the emission factor and mercury removal efficiencies of air pollution control devices are useful for development of a more accurate emission inventory.

我国政府已于2016年8月正式批准《关于汞的水俣公约》,大气汞污染防治是我国履约工作的重中之重,在我国的大气汞排放源中,燃煤部门的排放量占40％以上,是首要的控制对象,优先制定燃煤部门大气汞排放控制对策具有重要意义.本文分析了我国燃煤部门的履约要求,并从建立并更新燃煤部门大气汞排放清单、推行最佳可得技术/最佳环境实践(BAT/BEP)、实行全国汞减排总量控制、采用浓度控制和脱汞效率控制相结合的排放标准、强化汞污染防治监管体系五个方面,提出了我国燃煤部门履行《关于汞的水俣公约》的对策建议,为我国大气汞污染防治提供技术支持.

This study investigated the flow of mercury (Hg) associated with zinc (Zn), lead (Pb), and copper (Cu) concentrates and provided new insights on the Hg emissions and recovery in both metals-production and wastes-disposal processes in China. Total Hg input from concentrates consumed in China reached 1005.4 t, of which 31.7% was dumped as discarded slags and 2.3% was stabilized (permanent storage). Approximately 202.1 t of Hg was directly emitted to air, water, and soil. More specifically, metals production processes emitted 100.4 t Hg to air. Wastes disposal processes contributed to an additional 47.8 t of atmospheric Hg emissions (which were ignored in most emission inventories) and 32.7 and 21.3 t of Hg to water and soil, respectively. At the same time, out of the 62.6 t of recovered Hg, 95.2% was reclaimed from acid slags. Interim storage of 398.9 t of Hg also highlights the significance of acid slags as potential Hg recovery sources due to the global ban on primary Hg production. The uncertainty ranges (confidence interval: 10%-90%) for Hg emissions to air, water, and soil and for Hg recovery were (-75%, 89%), (-96%, + 111%), (-120%, + 149%), and (-78%, 92%), respectively.

为研究中国燃煤电厂中汞的去向,基于2010年中国各省份燃煤中的汞含量、燃煤消耗量、燃煤电厂大气污染控制设备的安装比例以及粉煤灰、脱硫石膏的二次利用方式,计算了我国燃煤电厂2010年向大气、水体、土壤中捧放汞的量.2010年我国电厂燃煤共输入汞271.7t (147.1～403.60.煤炭在电厂燃烧一次排放到大气中的汞为101.3t (44.0～167.1t),进入燃煤副产物、水体的汞分别为167.4t(84.3～266.3t),3.0t (1.2～5.0t).燃煤副产物二次利用过程向大气排放的汞为32.7t (12.5～56.1t),进入土壤中的汞为58.6t(33.6～103.9t),还有76.1t(30.3～108.6t)汞留在了产品中.结果表明,粉煤灰用于水泥生产和粉煤灰制砖是副产物向大气中二次排放的重要源,分别占总二次排放量的81.7％和15.3％.

The mercury (Hg) flow paths from three zinc (Zn) smelters indicated that a large quantity of Hg, approximately 38.0-57.0% of the total Hg input, was stored as acid slag in the landfill sites. Approximately 15.0-27.1% of the Hg input was emitted into water or stored as open-dumped slags, and 3.3-14.5% of the Hg input ended in sulfuric acid. Atmospheric Hg emissions, accounting for 1.4-9.6% of the total Hg input, were from both the Zn production and waste disposal processes. Atmospheric Hg emissions from the waste disposal processes accounted for 40.6, 89.6, and 94.6% of the total atmospheric Hg emissions of the three studied smelters, respectively. The Zn production process mainly contributed to oxidized Hg (Hg2+) emissions, whereas the waste disposal process generated mostly elemental Hg (Hg0) emissions. When the emissions from these two processes are considered together, the emission proportion of the Hg2+ mass was 51, 46, and 29% in smelters A, B, and C, respectively. These results indicated that approximately 10.8±5.8 t of atmospheric Hg emissions from the waste disposal process were ignored in recent inventories. Therefore, the total atmospheric Hg emissions from the Zn industry of China should be approximately 50 t.