铅鼓风烧结的改进

铅鼓风烧结－鼓风炉熔炼工艺是世界铅阈炼的主要生产工艺，在我国也有几十年的应用实践。我国的铅鼓风烧结技术与世界水平相比，在烧结床能力、脱硫强度、自动控制等相对落后，从而导致烟气、粉尘对环境的污染。本文针对我国铅烧结存在的问题，提出改进措施，以彻底改变烧结的落后现状。     

我国铅冶炼的技术现状及进展

简述了我国铅冶炼的生产现状,介绍了传统烧结炼铅工艺、熔池炼铅新工艺、再生铅冶炼工艺、液态高铅渣直接还原技术等进展,指出应大力推广液态高铅渣还原技术,废旧电池自动分离-底吹熔炼新工艺将成为再生铅冶炼的主流工艺。     

铅冶炼技术的发展现状及旋涡闪速炼铅工艺

铅是发展国民经济的重要基础原材料,然而,传统的烧结-鼓风炉熔炼工艺具有能耗大和污染重等缺陷,因此,加快铅冶炼技术的科技进步对整个国民经济的可持续发展具有重要意义.文中综述了Kivcet法、QSL法、Kaldo法、Ausmelt/Isasmelt法、SKS法等国内外直接炼铅新工艺,重点介绍了具有我国自主知识产权的旋涡闪速炼铅工艺过程、主要设备及技术特点.     

铅烧结工艺改造的思路

针对铅烧结烟气的治理，展开关于铅烧结工艺改进的分析，提出铅烧结工艺改进的几种思路。     

富铅渣与铅烧结块在还原反应中的差异研究

选用实验室制备的不同PbO含量的富铅渣与工业化生产的铅烧结块在竖管炉中用石墨坩埚进行还原反应对比试验。结果表明,烧结块和富铅渣主要以液相形式与碳反应。它们之间由于结构上的差异对还原反应的影响要小于成分的影响。     

铅烧结配料专家系统

介绍针对株洲冶炼厂铅粗炼分厂现场生产而建立的铅烧结配料专家系统。阐述了建立专家系统工具的选择、铅烧结配料领域专家知识的归纳、整理、编程及专家系统的检验。本专家系统符合率高,对现场生产有指导意义。     

治理水口山铅冶炼烟气污染的方案探讨

针对水口山矿务局铅冶炼烟气治理,将国内外的炼铅工艺进行了分析比较,论证了鼓风烧结－鼓风炉熔炼流程目前是治理水口山铅冶炼污染的最佳技术方案,对并提高铅烧结烟气ＳＯ２浓度提出了看法。     

铅烧结工艺改造的思路

针对铅烧结烟气的治理，展开关铅烧结工艺改进的分析，提出铅烧结工艺改进的几种思路。     

希尔姑兰炼铅厂

希尔姑兰（Herculaneum）炼铅厂位于美国密苏里州的东南部，始建于１８９２年，至今有１１０年的历史。在这１１０年间，该厂不断发展，至上世纪６０年代它已拥有三台现代化炼铅鼓风炉，年产铅能力２５万t。自上世纪６０年代以来，该冶炼厂不断提高生产效率、产品质量、职工安全保证程度、工业生产卫生条件以及环境保护水平。希尔姑兰炼铅厂是世界上最大的炼铅厂之一。在历史上，它曾经是熔炼产自密苏里州东南地区铅矿的工厂，后来它熔炼的铅精矿来自世界各地。希尔姑兰炼铅厂的生产流程是烧结—鼓风炉熔炼流程：铅精矿经烧结机烧结后，送…     

微波消解-火焰原子吸收光谱法测定铅烟灰和铅泥中银

采用王水和氟化铵在微波消解仪中消解样品,建立了火焰原子吸收光谱法测定铅烟灰和铅泥中银的方法。考察了溶样方法、消解试剂、微波消解程序、盐酸浓度和干扰离子对测定的影响。结果表明,以王水和氟化铵为消解试剂,采用三步消解程序即60℃、8 atm/1 min, 70℃、13 atm/2 min, 100 ℃、20 atm/3 min,效果最佳;铅泥和铅烟灰中的铜对银的测定没有影响;银浓度在0.2~10 μg/mL范围内与吸光度呈线性关系,方法检出限为0.03 μg/mL。采用本方法对铅烟灰和铅泥样品中的银进行分析,测得结果与常规溶样-原子吸收光谱法基本吻合,相对标准偏差（RSD,n=5）为1.1%~1.3%。     

Urinary non-precipitable lead in lead workers

Sixty-six workers engaged in lead-glazing pottery with a presumed moderate exposure to lead were studied. The group comprised 20 men with long-term exposure to lead and positive laboratory signs of increased lead absorption (Group A); 22 with long-term exposure and negative laboratory signs (Group B); 11 with short-term exposure and positive laboratory signs (Group C); and 13 with short-term exposure and negative laboratory signs (Group D). In addition, 14 workers employed in casting the kelmet alloys with presumed heavy exposure to lead (Group E) and seven healthy individuals (Group F) were included. Urine samples from all the subjects were analysed to determine, first, the total lead using the ashing technique, and then the precipitable lead using the coprecipitation technique of Cholak, Hubbard, and Burkey (1948), but modified slightly by us. Thus, the non-precipitable lead fraction in urine was the difference between the two measurements and this was also expressed as a percentage of the total lead. The mean total lead and the mean proportion of non-precipitable lead were 0.62 mumol/l and 48.7%, 0.35 mumol/l and 44.9%, 0.40 mumol/l and 48.9%, 0.17 mumol/l and 24.6%, 1.43 mumol/l and 44.3%, 0.14 mumol/l and 18.8% for Groups A, B, C, D, E, and F respectively, showing that a large part of urinary lead was eliminated as precipitable lead in Groups D and F who had normal lead excretion, while about half was eliminated as non-precipitable lead in the other four groups who had excessive lead excretion. No essential difference in the proportion of non-precipitable lead among Groups A, B and C excluded the possibility that the proportion might be directly related to the period of exposure to lead and to the laboratory findings of excessive lead absorption. The mean proportion of non-precipitable lead for the physiological (up to 0.240 mumol/l), intermediate (0.241 to 0.721 mumol/l), and excessive (above 0.722 mumol/l) total lead levels was 26.7, 41.3, and 52.3% respectively, in the lead workers comprising Groups A, B, C, and E each showing increased lead excretion when grouped together. these data suggested that, when urinary lead is within the normal range, it is excreted largely as precipitable lead even in individuals exposed to lead, and that the principal conditions determining the excretion of non-precipitable lead would be the current or recent degree of lead absorption. The excretory mechanisms and the biological significance of the non-precipitable lead are also discussed.     

论铅业的废铅资源

采用废铅指数(S)作为衡量废铅资源状况的指标,简明地分析了铅产量变化、废铅回收状况与S值之间的关系。结果表明,铅产量增长,会造成废铅资源短缺;反之,产量下降,废铅资源将比较充足;产量不变,废铅资源状况介于以上二者之间。废铅实得率愈高,废铅资源愈充足。根据统计数据,估算了1990～2000年间中国、瑞典、美国的S值,讨论了这三个国家S值不同的原因及其今后可能发生的变化。     

Electroextraction of lead from a lead trilonate solution

Laboratory studies of the cathode process of the electroextraction of zinc from the trilonate electrolyte obtained after the purification of solutions after leaching lead cakes of zinc production are performed. The potential scan rate is determined by recording potentiodynamic curves; the optimal electrolyte acidity, the composition, and the temperature are established. Values of activation energy confirming the concentration nature of process polarization are found.     

Plasma and blood lead concentrations, lead absorption, and lead excretion in nonhuman primates

The effects of pH, temperature, block of energy production, calcium/calmodulin, protein phosphorylation, and cytoskeleton-disrupting agents (cytochalasin D, nocodazole) on the integrity of the membrane skeleton were studied in polarized MDCK cells. The intracellular distributions of alpha-fodrin, actin, and ankyrin were monitored by immunofluorescence microscopy. The membrane skeleton, once assembled, seemed to be quite stable; the only factors releasing alpha-fodrin from the lateral walls were the acidification of the cytoplasm and the depletion of extracellular calcium ions. Upon cellular acidification, some actin was also released from its normal location along the lateral walls and was seen in colocalization with alpha-fodrin in the cytoplasm, whereas ankyrin remained associated with the lateral walls. No accumulation of plasma membrane lipids was observed in the cytoplasm of acidified cells, as visualized by TMA-DPH. These results suggest that the linkages between the fodrin-actin complex and its membrane association sites are broken upon acidification. The pH-induced change in alpha-fodrin localization was reversible upon restoring the normal pH. Reassembly of the membrane skeleton, however, required temperatures above +20 degrees C, normal energy production, proper cell-cell contacts, and polymerized actin. Release of alpha-fodrin from the lateral walls to the cytoplasm was also observed upon depletion of extracellular calcium ions. This change was accompanied by the disruption of cell-cell contacts, supporting the role of proper cell-cell contacts in the maintenance of the membrane skeleton polarity. These results suggest that local alterations of the cytoplasmic pH and calcium ion concentration may be important in regulating the integrity of the membrane skeleton.     

Survey of lead exposure around a closed lead smelter

OBJECTIVE: To test the hypothesis that elevated lead in soil is positively correlated with blood lead (BPb) levels in children in an urban population surrounding a closed lead smelter, a US Environmental Protection Agency Superfund clean-up site was surveyed. METHOD: A total of 827 volunteers including 490 children under 6 years of age participated. A questionnaire was administered. Blood lead was determined as was lead content of samples of house dust, soil, paint, and water of the participants' homes. RESULTS: The arithmetic mean venous BPb in 490 children between 6 and 72 months of age was 6.9 micrograms/dL (0.33 mumol/L) range 0.7 to 40.2 micrograms/dL (0.03 to 1.94 mumol/L). The BPb of 78 (16%) children in this group was > or = 10 micrograms/dL (0.48 mumol/L). Based on multiple regression modeling, lead in house dust accounted for 18% of the variance in BPb. Lead in paint together with the condition of the house were the main contributors to the dust lead variance (26%) with soil lead accounting for an additional 6%. Lead in paint alone accounted for 3% of the BPb variance. Lead in paint together with the condition of the house accounted for 12% of BPb variance, and lead in soil accounted for an additional 3%. Factors other than environmental lead such as education of parents, household income, and behavior were associated with BPb levels. CONCLUSIONS: The mean BPb in children was below the present level of concern of the Centers for Disease Control and Prevention. Children with BPb of > or = 10 micrograms/L (0.48 mumol/L) tended to live in poorly maintained older houses. Based on these findings lead in soil and paint in well-maintained homes contributed little to the lead exposure of children.     

The settling of metallic lead from lead blast furnace slag

As a consequence of inadequate working methods, excessive losses of lead can occur in the slags of lead blast furnaces. The settling of metallic lead from a slag containing 20.5 pct SiO₂, 33.4 pct FeO, 16.8 pct CaO, 12.4 pct ZnO, 0.9 pct S, and 6.1 pct Pb has been studied as a function of the temperature (1200 to 1300 °C), composition (addition of CaO, ZnO, and Fe), and time (up to 2 hours). Under these conditions sufficient, although not total, sedimentation of the metal retained is achieved. The best conditions were obtained at 1260 °C with no modification to the composition of the slag. The settled lead was visible macroscopically in a section of the lower part of the melts.     

Relationship between lead mining and blood lead levels in children

The authors studied blood lead levels of 226 randomly selected children, aged 6-92 mo, who lived in either a lead-mining area or a nonmining area, and 69 controls. The authors sought to determine to what extent mining activities contributed to blood lead levels in the children. The mean blood lead levels in the study and control groups were 6.52 microg/dl and 3.43 microg/dl, respectively. The corresponding proportions of children with elevated blood lead levels were 17% and 3%. Soil and dust lead levels were up to 10 times higher in the study than the control group. Elevated blood lead levels appeared to result from exposure to both lead-mining waste and lead-based paint. Mining waste was the cause of the higher prevalence of elevated blood lead levels in these children.