Gasification and smelting system using oxygen blowing for plastic waste including polyvinyl chloride

A new type of waste gasification and smelting system using oxygen blowing based on high-temperature metallurgy, was developed by Sumitomo Metals, Japan. This system can steadily gasify and melt not only municipal waste, but also plastic waste and polyvinyl chloride (PVC) waste by using a top-blow oxygen lance together with sideways-blow oxygen lances. As a result of gasification in the high-temperature reducing atmosphere and rapid gas cooling, dioxin-free, high-calorie purified gas was produced. Ash components in the wastes were smelted in a high-temperature reducing atmosphere, and high-quality slag free of heavy metals was produced. Most of the chlorine in the wastes was converted into hydrogen chloride in the off gas. The hydrogen chloride can be recovered as hydrochloric acid or chlorine, which are recyclable to PVC manufacturing.     

The Appalachian Mountains' Copper Basin and the concept of environmental susceptibility

The Copper Basin is located within the southern Appalachian Mountains primarily in extreme southeastern Tennessee, USA. It has long been known for its copper mining/smelting and associated chemical industry, as well as its severely injured environment. Virtually all previous commentary on the environmental degradation at this location have focused on human activities and their destructive impact. This article approaches the subject from a different angle, one that emphasizes the interaction between man and nature. The site's physical setting, industrial history, and environmental history are briefly reviewed. The theory then presented here is that certain of the Copper Basin's natural features made its environment unusually vulnerable to the negative impact of copper mining and smelting, especially as practiced around the turn of the century. These features are identified. This reasoning provides the basis for the concept of environmental susceptibility, which is defined and discussed. A few of its applications are mentioned. This study offers a new perspective on the Copper Basin, as well as insights for those whose work involves investigating the man/nature relationship—both past and present.     

锌冶炼烟尘中铅汞分布及形态研究

锌精矿脱硫焙烧烟气降温过程中,烟尘的性质及其中铅汞存在形态的变化规律是冶炼烟气重金属(Pb和Hg)污染控制的重要依据。通过电感耦合等离子体-原子发射光谱(ICP-AES)、激光粒度分析及筛分分析了不同降温收尘环节烟尘元素成分及粒度变化。烟尘主要含Zn、Fe、Ca、Cd、S、Pb元素,其累积质量分数达69.90%~77.62%,而Hg含量较低。烟尘粒径随烟气温度降低呈先增大后减小的变化规律,中位径由沸腾焙烧炉排出的28μm升至经余热锅炉降温后的36μm,再逐级降至经电收尘器后的5.6μm。据此,重点分析了Pb和Hg在烟气中的分布,并借助X射线光电子能谱(XPS)分析了其存在形态。结果表明,随烟气温度降低,烟气中Pb和Hg含量呈上升趋势,Pb由2.8%增至9.2%,Hg由4.8μg/g增至109.1μg/g。不同工艺环节的烟尘中Pb均以PbSO_4和含Pb—O键的复杂Pb配合物的形式存在。Hg变化较为明显,仅沸腾焙烧炉烟尘样品中能够检测到HgS与HgSO_4,其余工艺环节烟尘样品中无含Hg化合物的特征峰。     

采冶矿活动对贵州省赫章县地下水质量影响的空间特征

以赫章县地下河和泉为对象,通过采样、水质分析研究采冶矿活动对县域地下水中元素含量的影响,运用地下水质量标准(GB/T14848-93)评价其水质状况,并采用GIS软件揭示水质变化的空间特征。结果表明,赫章县地下水Fe、Mn、Pb元素平均含量超过国家地下水环境质量Ⅲ类标准,其中Fe的平均含量超过国标Ⅲ类水质量标准2.5倍,Mn超过1.4倍,Pb超过0.05倍。水体中Fe、Mn、Cu、Cd元素含量受区域原生地球化学环境控制,同时表生地球化学作用和人类活动也深刻影响水中元素的含量与分布。县域内地下水质量整体较好,较差水质仅分布在中部地区采冶矿点处,揭示了采冶矿带来的尾矿、矿渣经风化、蚀变、分解作用后向水体环境释放诸种重金属元素。     

论环评中铜冶炼行业的清洁生产评价

在环评中针对铜冶炼行业的现状,从工艺、设备、原材料、生产过程的控制、产品和管理等方面,进行清洁生产评价,同时阐述了清洁生产是预防和控制污染,实现可持续发展的必由之路,并就存在的问题提出自己的见解。     

Anthropogenic mercury emissions in China

An inventory of mercury emissions from anthropogenic activities in China is compiled for the year 1999 from official statistical data. We estimate that China's emissions were 536 (±236) t of total mercury. This value includes open biomass burning, but does not include natural sources or re-emission of previously deposited mercury. Approximately 45% of the Hg comes from non-ferrous metals smelting, 38% from coal combustion, and 17% from miscellaneous activities, of which battery and fluorescent lamp production and cement production are the largest. Emissions are heaviest in Liaoning and Guangdong Provinces, where extensive smelting occurs, and in Guizhou Province, where there is much small-scale combustion of high-Hg coal without emission control devices. Emissions are gridded at 30×30 min spatial resolution. We estimate that 56% of the Hg in China is released as Hg⁰, 32% as Hg²⁺, and 12% as Hg^p. Particulate mercury emissions are high in China due to heavy burning of coal in residential and small industrial settings without PM controls. Emissions of Hg²⁺ from coal-fired power plants are high due to the absence of flue-gas desulfurization units, which tend to dissolve the soluble divalent mercury. Metals smelting operations favor the production of elemental mercury. Much of the Hg is released from small-scale activities in rather remote areas, and therefore the activity levels are quite uncertain. Also, emissions test data for Chinese sources are lacking, causing uncertainties in Hg emission factors and removal efficiencies. Overall, we calculate an uncertainty level of ±44% (95% confidence interval) in the estimate of total emissions. We recommend field testing of coal combustors and smelters in China to improve the accuracy of these estimates.     

Serum and urine monitoring of fluoride exposed workers in aluminium smelting factory

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铅冶炼污染防治最佳可行技术筛选研究

分析了国外铅冶炼污染防治的相关政策、欧盟铅冶炼污染防治的最佳可行技术和我国铅冶炼技术现状,并应用层次分析-模糊综合评判法对铅冶炼污染防治技术进行筛选,利用层次分析法确定各评价指标的权重,利用模糊综合评判法进行铅冶炼污染防治技术的评价,通过评价提出铅冶炼污染防治的最佳可行技术工艺组合。     

钼冶炼行业二氧化硫尾气治理与回收利用技术

在分析国内外钼冶炼行业低浓度二氧化硫治理与回收利用技术的基础上,结合我国实际情况,重点介绍了采用多层大孔板洗涤塔洗涤净化焙烧回转窑烟气,回收亚硫酸钠技术。该技术有效地解决了高温、工况不稳定及强腐蚀等条件下含二氧化硫烟气治理难的问题,脱硫效率达到98%以上,实现了达标排放。回收亚硫酸钠和贵重金属钼、铼,具有显著的环境效益、经济效益和社会效益。     

Mercury contamination and health risk to crops around the zinc smelting plant in Huludao City,northeastern China

The Huludao zinc plant in Liaoning province, northeast China was the largest in Asia, and its smelting activities had seriously contaminated soil, water and atmosphere in the surrounding area. For the first time, we investigated the total mercury (THg) content in maize, soybean, broomcorn, 22 vegetables, and the soil around their roots from eight sampling plots near the Huludao zinc plant. THg contents of the seeds of maize, soybean, and broomcorn are 0.008, 0.006, and 0.057 mg kg⁻¹, respectively, with the broomcorn being the highest, exceeding the maximum level of contaminant in food (GB2762-2005) by 4.7 times. The edible parts of vegetables are also contaminated with a range of mercury contents of 0.001–0.147 mg kg⁻¹ (dry weight). THg contents in plant tissue decrease in the order of leaves > root > stalk > grain. Using correlation analysis, we show that mercury in the roots of these plants is mainly derived from soil, and the uptake of gaseous mercury is the predominant path by which the mercury accumulated in the foliage. The average and maximum mercury daily intake (DI) of adult around the Huludao zinc plant via consuming vegetables are 0.015 and 0.051 μg/kg/d, respectively, and those of children are 0.02 and 0.07 μg/kg/d, respectively. The average and maximum weekly intakes of total mercury for adult are 2.1 and 7.1%, respectively, of the provisional tolerable weekly intake (PTWI), and 2.8 and 9.7%, respectively, of the PTWI for children.