钢材盐酸酸洗废液资源化处理的研究

用盐酸作为钢材酸洗介质,会产生相当多的盐酸酸洗废液,废液如果直接排放会严重污染环境,而且浪费资源。以宝鸡瑞星化工机械厂和宝鸡铁塔厂的酸洗废液为原料,通过实验室小试,探索出了通过蒸馏浓缩以及浓缩液酸化制备盐酸的工艺条件;在此基础上设计了相关的工艺路线并进行中试,制得了浓度高达34%的盐酸,同时副产氧化铁红和磷肥;探讨了中试时所遇到问题的解决办法,并对中试结果进行了讨论。实践证明,该工艺不仅可消除酸洗废液对环境的污染,且有良好的经济效益,为钢材盐酸酸洗废液资源化处理综合利用提供了实用技术,是循环经济的很好实例。     

页岩-钢渣组合填料湿地强化脱氮除磷研究

以城市污水A/O工艺出水为处理对象,运用页岩和钢渣物化除磷、调控进水碳氮比和氮素氧化性等技术手段,在中试规模上研究了页岩和钢渣组合填料湿地的脱氮除磷效能及影响因素.结果表明,当COD面积负荷率、TN面积负荷率、TP面积负荷率、HRT(水力停留时间)分别为6.5～20.7 g·(m²·d)^-1、2.57～8.22 g·(m²·d)^-1、0.41～1.32 g·(m²·d)^-1、0.5～1.6d时,①氨氮、亚硝态氮和硝态氮的去除率分别为85.8%、56.3%和18.6%,TN去除率为58.0%,TN面积负荷去除率为3.58g·(m²·d)^-1,TN反应动力学常数为0.31 m·d^-1,TN面积负荷去除率随进水TN负荷的增加而线性增加.②TP去除率为90.4%,TP面积负荷去除率为0.89 g·(m²·d)^-1,TP反应动力学常数为0.86 m.d^-1,TP面积负荷去除率随进水TP负荷的增加而线性增加.③水温、HRT、氮素组分、C/N等因素对湿地系统的脱氮除磷效率有显著影响.TN面积负荷去除率随HRT、COD/TN值的增加而幂函数增加.TN面积负荷去除率随水温(、NO₂^--N+NO₃^--N)/TN值的增加而呈指数函数增加.     

Ancient manuring practices pollute arable soils at the St Kilda World Heritage Site, Scottish North Atlantic

The impact of ancient fertilization practices on the biogeochemistry of arable soils on the remote Scottish island of Hirta, St Kilda was investigated. The island was relatively unusual in that the inhabitants exploited seabird colonies for food, enabling high population densities to be sustained on a limited, and naturally poor, soil resource. A few other Scottish islands, the Faeroes and some Icelandic Islands, had similar cultural dependence on seabirds. Fertilization with human and animal waste streams (mainly peat ash and bird carcases) on Hirta over millennia has led to over-deepened, nutrient-rich soils (plaggen). This project set out to examine if this high rate of fertilization had adversely impacted the soil, and if so, to determine which waste streams were responsible. Arable soils were considerably elevated in Pb and Zn compared to non-arable soils. Using Pb isotope signatures and analysis of the waste streams, it was determined that this pollution came from peat and turf ash (Pb and Zn) and from bird carcases (Zn). This was also confirmed by ¹³C and ¹⁵N analysis of the profiles which showed that soil organic matter was highly enriched in marine-derived C and N compared to non-arable soils. The pollution of such a remote island may be typical of other ‘bird culture’ islands, and peat ash contamination of marginal arable soils at high latitudes may be widespread in terms of geographical area, but less intense at specific locations due to lower population densities than on Hirta.     

Formation of ferric flocks to remove for the removal of Zn and Cu from dockyard wastewater

Wastewater from wash down of boat hulls contains typically Cu, Zn and organometallic biocides, e.g. tributyltin (TBT). In some cases this wastewater is led directly into the marine system. In the present paper, a cheap flocculation method (iron flocculants) for removal of Cu and Zn from the wastewater is investigated and the method was shown successful. TBT concentration in a sample from a German dockyard was also decreased during flocculation, but the TBT removed was already associated with small particulates in the original sample. Low concentrations of heavy metals were obtained by flocculation: <0.05 mg Cu/l and 0.2 mg Zn/l. An erratum to this article can be found at     

Cu和Cd胁迫下接种外生菌根真菌对油松根际耐热蛋白固持重金属能力的影响

铜和镉是我国土壤重金属常见种类,生物固定过量重金属以降低其生理毒害是修复土壤重金属污染的有效方法之一.外生菌根能够通过分泌大量有机物质来降低土壤中重金属的生物有效性.在Cu或Cd胁迫下,外生菌根真菌接种油松幼苗根际分泌的耐热蛋白具有固持重金属的潜力.结果表明,纯培养条件下接种并没有增加耐热蛋白的分泌,但是在Cu或Cd的胁迫培养下,接种幼苗耐热蛋白的分泌量增加.不同Cu浓度处理下,接种油松幼苗总提取耐热蛋白(total thermostable protein,TTP)和易提取耐热蛋白(easily extracted thermostable protein,EETP)的分泌量为未接种油松的2.64~11.79倍;Cd处理下接种油松TTP和EETP的分泌量,分别是未接种油松的1.49~7.56倍.虽然Cu处理下无论是接种还是未接种,根际耐热蛋白和根系细胞中固持的总Cu量显著大于空白对照,但接种显著增加了根际的重金属固持量,其Cu总相对含量是未接种的1.81~2.75倍,且绝大部分重金属固持在耐热蛋白中,使得根际耐热蛋白中的Cu相对含量是根系细胞含量的4.19~43.00倍.Cd处理下也得到了相似的结论.说明接种菌根真菌促进了植物分泌耐热蛋白量,加强了根系对重金属的固持能力,从而达到减少过量重金属的生物有效性,缓解土壤重金属污染的目的.     

吸附Cu~(2+)接枝纤维的制备与表征

以漂白蔗渣浆纤维素为基体,二乙烯三胺为单体,硝酸铈铵为引发剂,制备胺基接枝纤维,制备高效重金属吸附剂。研究了单体用量、引发剂用量、温度、时间等反应因素对胺基接枝纤维制备的影响。采用红外光谱、X射线衍射和扫描电镜分析表征胺基接枝纤维的结构。结果表明:绝干蔗渣纤维:单体二乙烯三胺=1:1(质量比),硝酸铈铵的用量为25%,温度为70℃,时间为2 h时可以获得较高的吸附量,其吸附量可以达到12.8 mg/g。通过红外光谱和扫描电镜分析手段,对接枝纤维的结构进行表征。     

某退役辐照装置储源井钢件表面沾污测量

利用物理测量及擦拭法对某退役辐照装置储源井钢件进行表面沾污测量及结果验证,结果表明,本次测量中两种方法测量结果基本一致。物理法受测量物体自身结构及尺寸的影响导致测量结果存在误差,擦拭法要保证较高的去除因子。擦拭法可对物理法测量结果进行验证。     

北方某大型钢铁企业表层土壤中多环芳烃污染特征与健康风险评价

采集我国北方某大型钢铁企业22个表层土壤(0~20 cm)样品,采用气相色谱-质谱联用仪(GC-MS)分析了土壤中16种优控多环芳烃(PAHs)的含量.结果表明,土壤中Σ16PAHs含量范围为22.0~20 062.0μg·kg~(-1),且以中高环(4、5环)为主,单体以Flu、Pyr的含量最高.与同类相关研究比较,该钢铁厂表层土壤中PAHs污染处于中等水平,中、重度污染采样点主要位于焦化厂、球团厂等典型区域.20个采样点PAHs单体均超过荷兰土壤质量标准中10种PAHs的目标值,而与北京工业场地土壤筛选值相比,仅部分采样点BaA、BaP超标.源解析结果表明,表层土壤中PAHs主要来源于以煤为主的化石燃料的燃烧,石油类燃烧和泄漏的贡献较少.健康风险评价结果表明,BaP、BaA、DBA、BbF、InP在居住用地条件下的致癌风险超过了1×10~(-6),BaP、BaA、DBA在工业用地条件下的致癌风险超过了1×10-6,BaP的致癌风险最大,该钢铁厂表层土壤中PAHs已对人群健康产生危害,需实施土壤修复工程.     

典型钢铁行业汞排放特征及质量平衡

以重庆市某钢铁企业各工艺单元的进出物料为研究对象,分析样品总汞及各物料中汞的输入输出量,初步探讨钢铁生产各工序汞的排放特性及其质量平衡.结果发现,各工艺输入物料汞含量为2.93~159.11μg·kg~(-1),其中,高炉所用块矿汞含量最高,其次为烧结以及高炉用煤.输出物料中汞含量为3.09~18.13μg·kg~(-1),除尘灰汞含量最高,其次为转炉渣.该钢铁企业自备焦化厂汞输入量和输出量分别为1 346.74 g·d~(-1)±36.95 g·d~(-1)和177.42 g·d~(-1)±13.73 g·d~(-1),焦化工序中的汞主要来源于焦煤的燃烧.钢铁生产过程中烧结工序汞输入量最高,为1 075.27 g·d~(-1)±60.89 g·d~(~(-1)),占钢铁生产总汞带入量的68.06%,其来源主要是铁矿粉.固体输出物料中,烧结工序输出汞量为14.15 g·d~(-1)±0.38 g·d~(-1),占总固体输出量22.61%.经估算,该钢铁企业2013年汞排放量约为553.83 kg,汞排放因子为0.092 g·t~(-1)钢产量.为控制汞排放,钢铁企业应结合生产实际,进一步降低焦化以及烧结工序能耗水平,或提高原料质量,减少汞的输入.     

Metal-cored arc welding process for joining of modified 9Cr-1Mo (P91) steel

In the present work, metal-cored arc welding process was used for joining of modified 9Cr-1Mo (P91) steel. Metal-cored arc welding process is characterized by high productivity, slag-free process, defect-free weldments that can be produced with ease, and good weldability. Toughness is essential in welds of P91 steel during hydro-testing of vessels. There is a minimum required toughness of 47 J for welds that has to be met as per the EN1557:1997 specification. In the present study, welds were completed using two kinds of shielding gases, each composition being 80% Argon + 20% CO₂, and pure argon respectively. Microstructural characterization and toughness evaluation of welds were done in the as – weld, PWHT at 760 °C – 2 h and PWHT at 760 °C – 5 h conditions. The pure argon shielded welds (‘A2’ and ‘B2’) have higher toughness than 80% argon + 20% CO₂ shielded welds (‘A1’ and ‘B1’). Pure argon shielded welds show less microinclusion content with low volume fraction of δ-ferrite (<2%) phase. Themo-calc windows (TCW) was used for the prediction of equilibrium critical transformation points for the composition of the welds studied. With increase in post-weld heat treatment (PWHT) duration from 2 h to 5 h, there was increase in toughness of welds above 47 J. Using metal-cored arc welding process, it was possible to achieve the required toughness of more than 47 J after PWHT at 760 °C – 2 h in P91 steel welds.