共查询到19条相似文献,搜索用时 171 毫秒
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研究了水泥窑炉协同处置垃圾焚烧飞灰过程中重金属挥发特性,探讨了水泥工业协同处置城市生活垃圾焚烧飞灰的技术及其可行性。研究结果表明,飞灰中重金属挥发率随着煅烧温度的升高而升高;在水泥高率值配方条件下飞灰的重金属挥发率要高于在低率值配方条件下的挥发率;重金属元素中Mn、Cr、Zn、Cu的挥发率相对较低,1 450℃以下挥发率大多小于40%;Pb、Cd的挥发率相对较高,在1 450℃挥发率可达到90%~100%。水泥矿物对重金属元素中Mn、Cr、Zn、Cu的固化效果较好,对Ba、Pb、Cd的固化效果较差,因此在水泥生产过程中应加强粉尘回收,防止造成环境污染。 相似文献
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对合肥市南淝河表层沉积物中重金属污染状况进行采样调查,选取了8个采样点,测定了沉积物中Cr、Cd、Pb、Ni、Zn、Cu 6种重金属的含量,并采用地质累积指数法和Hakanson潜在生态风险指数法对其污染程度进行分析评价。地质累积指数评价结果表明:南淝河6种重金属的生态风险等级由强至弱依次为Cd、Zn、Cu、Ni、Pb、Cr;生态风险指数评价结果显示:在南淝河沉积物重金属中,Cd存在一定的潜在生态风险,Cr、Pb、Ni、Zn、Cu均处于轻微等级,重金属生态风险等级由强至弱依次为Cd、Cu、Ni、Pb、Zn、Cr,多数采样点的沉积物重金属综合潜在生态风险等级处于轻微级,个别采样点达到了中等甚至强生态风险等级。 相似文献
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《煤炭加工与综合利用》2016,(3)
通过对贵州省六盘水市煤炭矿区土壤中Cr、Cd、Zn、Cu、Ni、Pb共6种重金属元素的测定,应用地积累指数法和生态危害指数法对3座矸石山周边土壤重金属污染状况进行分析和评价;结果表明:土壤重金属含量在平面上与煤矸石山距离总体成负相关趋势,最大污染点位置与煤矸石周边环境条件相关;煤矸石周边土壤中Cd、Pb、Zn污染程度最严重,其中Cd潜在生态风险系数最大,污染主要集中于土壤表土层,对深层土壤环境影响不大;Cu、Ni、Zn总体污染程度不高,对土壤环境影响较轻。 相似文献
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为研究生活垃圾焚烧炉渣应用于道路基层对环境的影响,首先分析炉渣的理化性质和重金属浸出特性,其次通过室内模拟浸出试验,研究炉渣替代率分别为0%、10%、17%和27%的水泥稳定炉渣碎石混合料的重金属浸出特性.结果表明:炉渣内部晶体发育良好,重金属Zn、Cd、Ni、Cr、Pb、Cu浸出浓度低,属无害固废;炉渣参与炉渣碎石的水化反应,使炉渣碎石中针棒状晶体、孔隙数量和孔隙直径明显减少,结构更密实;整个试验过程中,炉渣碎石的Zn、Cd、Ni、Cr、Pb、Cu浸出浓度均低于《填埋标准》和《景观标准》限值,对环境影响较小;但炉渣替代率对炉渣碎石中不同重金属的浸出行为影响不同,尤其对Zn的浸出行为影响较大,因此在实际使用时应通过试验确定合适的炉渣替代率. 相似文献
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本论文研究了南四湖沉积物中重金属的含量及生态风险;结果表明沉积物重金属Cd、Cr、Cu、Pb、Zn、Ni、Co的含量为0.08~1.12、58.92~135.62、38.09~78.65、24.51~53.95、110.51~235.36、11.30~65.40、4.12~20.14 mg/kg,均值顺序Zn Cr Cu Pb Ni Co Cd;重金属生态风险评价结果表明,Cd和Zn的相对富集因子明显高于其它元素,且某些点这两种元素的富集程度较高。因此,在南四湖环境污染防控中,应该关注沉积物中的Cd、Zn的污染。 相似文献
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The aim of this study has been to investigate the chemistry and volatility of the heavy metals As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn on the grate of a MSW fired furnace, using equilibrium calculations. Focus has been on the influence of varying MSW composition and operational parameters such as air/fuel ratio and temperature. Equilibrium distributions at 950–1600 K, under reducing and oxidising conditions on the grate, showed that Cd, Hg and Pb are fully volatilised. However, Cr is found to be stable in solid phase, in the entire temperature range. The volatile behaviour of Cd, Cr, Hg and Pb show no significant influence, while As, Cu, Ni and Zn are strongly influenced by one or more of the parameters; temperature, fuel/air and chlorine/metal ratios. 相似文献
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垃圾水分对垃圾焚烧过程重金属迁移转化影响的实验研究(英文) 总被引:2,自引:0,他引:2
The effect of moisture in municipal solid waste (MSW) on partitioning of lead (Pb), zinc (Zn), copper (Cu) and cadmium (Cd) was studied in a laboratory tubular furnace by using simulated MSW. The moisture in MSW influences heavy metals in following ways, to increase the moisture in flue gas and decrease the combustion temperature, to prolong the combustion time, and to prolong the releasing time of volatiles with the furnace temperature decreased by increasing the moisture. The volatilization of Pb, Zn and Cd was enhanced by increasing the moisture in MSW because of the prolonged combustion time. For Pb and Zn, the combustion time was important at higher temperature, while for Cd, it was important at low temperature. The moisture content showed slight effect on Cu partitioning. When extra chlorine was added to MSW, such as 1%PVC + 0.5%NaCl, the volatilization of Pb, Zn and Cu was enhanced by increasing the moisture because water evaporation reduced the temperature and increased devolatilization time. At higher temperature, NaCl tends to decompose and generates more free chlorine, producing more metal chlorides. Since Cd is a strong volatile heavy metal in MSW, the effect of moisture content on its volatilization is less than that of Pb, Zn or Cu during the MSW incineration. 相似文献
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采用微波消解法对惠州市五个县区采集的71个蔬菜样品进行前处理,用ICP-AES测定蔬菜中As、Cd、Cr、Cu、Ni、Pb、Zn等7种元素含量,并对五个县区蔬菜重金属污染情况进行统计分析。结果表明:五县区蔬菜主要受Cd和Zn的污染,As、Cr、Cu、Ni、Pb等含量均未超过国家限量标准,叶菜类蔬菜重金属含量相对较高,瓜果类及卷心类蔬菜重金属含量比较低。 相似文献
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通过分析污泥热水解处理过程中重金属含量与形态的变化,考察不同温度(120~200℃)和不同处理时间(15~90min)对污泥中重金属(Cr、Mn、Ni、Cu、Cd、Pb)迁移转化和环境风险的影响,并对污泥热水解过程中理化参数[挥发性固体(VS)、溶解性蛋白质、多糖、溶解性化学需氧量(SCOD)、碱度、NH4+-N和pH]与重金属生物可利用性变化的相关性进行了分析。结果表明,热水解处理后污泥得到有效破解,部分重金属释放进入液相,但大部分重金属仍残留在固相中。固相中Cr和Mn含量在处理温度较高时(≥180℃)较原泥升高,其他重金属含量均低于原泥。热水解处理后大部分重金属(除Pb外)弱酸提取态占比随处理温度升高和处理时间延长呈下降趋势,且处理后污泥中Cr、Ni、Cu、Cd和Pb残渣态占比明显上升。具有生物有效性重金属含量与污泥NH -N、SCOD、溶解性蛋白质、VS等指标变化有较强相关性。单个重金属生态风险变化与重金属迁移转化密切相关,污泥重金属总潜在生态风险RI在热水解处理后显著降低。 相似文献
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Content, mobility and transfer behavior of heavy metals in MSWI bottom ash in Zhejiang province, China 总被引:2,自引:0,他引:2
Municipal solid waste incinerator (MSWI) bottom ash samples were taken from six cities of Zhejiang province, where 1/4 incinerators of China were located. The samples were instrumentally analyzed to detect the content of heavy metals. Sequential extraction procedure (SEP) was adopted to characterize the mobility and environmental impact of heavy metals. And the transfer coefficients of heavy metals from the input MSW to the bottom ash during the incineration were also calculated. It showed that the average content of Zn, Mn, Cu, Pb and Cr in the bottom ash exceeded 300 mg/kg, which was much higher than that in the soils. SEP results showed that although the residue fraction was the primary fraction of the heavy metals in the bottom ash, there were still 1.84 mg of Cd, 86.21 mg of Cu, 83.46 mg of Pb and 939.46 mg of Zn in 1 kg bottom ash having the potential of leaching, which indicated a great threat to the surrounding environment. The result of coefficients calculation revealed that almost all the Cu, Cr, Mn and Ni in the input MSW were transferred to the bottom ash during the incineration. Bottom ash was also the main destination of Cd, Co, As, Mo, Pb and Zn though considerable amounts of those metals were transferred to the raw gas. 相似文献
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扬州古运河是京杭大运河最古老的一段,为了解沉积物中重金属污染状况,采用Hakanson潜在生态风险评价扬州古运河三湾段沉积物中重金属Cr、Ni、Cu、Zn、Cd和Pb的风险水平,并对形态分布特征进行了研究。结果表明:扬州古运河六种重金属的含量均高于背景值,其中Cd含量为其背景值的13.15倍。沉积物中重金属的累积潜在生态风险指数RI高达456.55,沉积物的总体潜在生态风险等级为强。沉积物中Pb的主要赋存形态主要以铁锰氧化态存在,而Zn和Cd主要以酸可溶态形式存在,说明这三种重金属的潜在生态风险水平较高。 相似文献
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通过氧化硫硫杆菌生物淋滤处理城市垃圾焚烧飞灰中的重金属。采用分批摇床培养,研究了生物淋滤过程中,底物浓度(S)对飞灰中重金属去除速率的影响。采用经验方程研究了S浓度对飞灰中重金属去除速率的影响,得到不同S浓度下4种重金属(Cu、Zn、Cd、Pb)的去除速率常数km,其大小顺序为ZnCuCdPb。综合各个动力学参数推知S浓度为5 g/L是本生物淋滤体系的最佳底物浓度。 相似文献