云南某铜铅硫化矿石选矿试验

云南某低品位铜铅硫化矿石铜、铅品位分别为0.54%和2.12%。为确定铜、铅选矿工艺,采用铜铅混浮再分离的原则流程进行了选矿试验。结果表明：在磨矿细度为-0.074 mm占75.40%的情况下,采用1粗1扫2精铜铅混合浮选、1粗2扫3精铜铅分离流程处理矿石,可获得铜品位为25.32%、含铅7.96%、铜回收率为82.06%的铜精矿,铅品位为58.36%、含铜0.73%、铅回收率为85.61%的铅精矿。     

丹寨县某铅锌矿选矿试验

为给丹寨县某硫化铅锌矿石的开发利用提供技术依据,在对矿石进行工艺矿物学研究基础上,采用优先浮铅再浮锌流程进行了铅锌选矿试验。结果表明,在磨矿细度为-0.074 mm占80%,铅粗选CaO用量为2 500 g/t、ZnSO₄+Na2SO₃为1 500+1 000 g/t、乙硫氮+丁铵黑药为10+10 g/t、2^#油为18 g/t,锌粗选CuSO₄用量为600 g/t、丁基黄药用量为130 g/t情况下,采用1粗1精1扫浮铅、1粗1精2扫浮锌、中矿顺序返回流程处理该矿石,获得了铅品位为48.72%、含锌4.95%、铅回收率为89.21%的铅精矿,以及锌品位为45.89%、含铅0.72%、锌回收率为82.42%的锌精矿。     

Effect of cadmium, lead and arsenic on the oviposition, hatching and embryonic survival of Biomphalaria glabrata

Biomphalaria glabrata is a widespread freshwater gastropod mollusc. The easy aquaculture of these organisms allow its use as an accessible tool for contamination bioassays. B. glabrata showed marked metabolic responses when exposed to cadmium, lead and arsenic. Those responses could also affect the reproduction of the snails. Taking into account this hypothesis, B. glabrata were exposed for 96 h (acute laboratory bioassays) to different concentrations of cadmium (0.1, 0.05 and 0 mg/L), lead (0.5, 0.1, 0.05 and 0 mg/L) and arsenic (0.5, 0.1, 0.05 and 0 mg/L). Snails were removed from the aquaria while eggs were left in the same contaminant concentrations. The effect of the assayed toxicants on snail reproduction was registered as the alterations of the total number of laid eggs (TNLE), hatching time and embryonic survival.At 0.10 mg/L cadmium significantly decreased the TNLE (p < 0.05) and no embryos survived. The lowest assayed level (0.05 mg/L) of cadmium, delayed the hatching time twice when it was compared with the control group (p < 0.01).Lead decreased the TNLE at 0.5 mg/L level (p < 0.01). The other assayed doses (0.05 and 0.10 mg/L) also decreased embryonic survival significantly (p < 0.05 and p < 0.01 respectively) and extended twice the time to hatching (p < 0.01). The 0.50 mg/L level killed all embryos.Arsenic at all studied concentrations decreased the TNLE (p < 0.05) while the hatching time was increased by 50%. Embryo survival only decreased at the highest level (0.5 mg/L) of arsenic assayed.In summary, the acute exposure (96 h) to cadmium lead and arsenic, altered the reproduction of B. glabrata, modifying the TNLE, hatching time and embryonic survival.     

Lead in saliva from lead-exposed and unexposed children

Introduction

Whole blood is used for diagnosis of lead exposure. A non-invasive method to obtain samples for the biomonitoring of lead contamination has become a necessity. This study 1) compares the lead content in whole saliva samples (Pb-saliva) of children from a city with no reported lead contamination (Ribeirão Preto, São Paulo State, Brazil) and children of a region notoriously contaminated with lead (Bauru, São Paulo State, Brazil), and 2) correlates Pb-saliva with the lead content in the enamel microbiopsy samples (Pb-enamel) in the case of these two populations.

Methods

From a population of our previous study that had included 247 children (4- to 6-year-old) from Ribeirão Preto, and 26 children from Bauru, Pb-saliva was analyzed in 125 children from Ribeirão Preto and 19 children from Bauru by inductively coupled plasma mass spectrometry (ICPMS). To correlate Pb-saliva with Pb-enamel, we used Pb-enamel data obtained in our previous study. The Mann-Whitney test was employed to compare the Pb-saliva data of the two cities. Pb-saliva and Pb-enamel values were then Log₁₀ transformed to normalize data, and Pb-saliva and Pb-enamel were correlated using Pearson's correlation coefficient.

Results

Median Pb-saliva from the Ribeirão Preto population (1.64 μg/L) and the Bauru population (5.85 μg/L) were statistically different (p < 0.0001). Pearson's correlation coefficient for Log₁₀ Pb-saliva versus Log₁₀ Pb-enamel was 0.15 (p = 0.08) for Ribeirão Preto and 0.38 (p = 0.11) for Bauru.

Conclusions

A clear relationship between Pb-saliva and environmental contamination by lead is shown. Further studies on Pb-saliva should be undertaken to elucidate the usefulness of saliva as a biomarker of lead exposure, particularly in children.     

双硫腙萃取分离原子吸收光谱法测定铅电解液中微量银含量

采用HCl—NaCl处理铅电解液,将银转为可溶性配位离子,用EDTA掩蔽基体和少量其他干扰元素,于pH=5～6的乙酸钠缓冲液中,用0.002%双硫腙—四氯化碳萃取银,然后用0.5mol/L的HCl—1%NaCl反萃取液反萃取,水相原子吸收分光光度法测定。方法流程较短,操作简单,回收率在95%以上。     

我国生物源农药半世纪的回顾与启示

综述了我国生物源农药研发概况,对植物源、微生物农药的开发作了重点介绍。     

Effect of Gap Size on Coating Extrusion of Pb-GF Composite Wire by Theoretical Calculation and Experimental Investigation

1.IntroductionContinuous fiber composite wire has been of great im-portance for its high market potential in recent decade.Lead-clad glass fiber(Pb-GF)composite wire can bewidely used in various fields,including grid plates in bat-teries for electric vehicles(EVs)and hybrid electric vehi-cles(HEVs),radiation protective grid plates and soundinsulation,due to its high tensile strength,good resis-tance to acid corrosion,sound electric conductivity,highdamping and radiation protection of lead[1…     

固体样品直接进样石墨炉原子吸收光谱法测定土壤中的Pb

应用analytikjena公司SSA600全自动固体进样装置石墨炉原子吸收光谱法测定土壤中的Pb。此方法采用固体样品直接进样方式,省略土壤消解等繁琐步骤,大大缩短土壤样品的测定时间,消除由于复杂的消解过程所带来的各种干扰和误差。此方法经多种标土验证,效果甚佳。     

无铅焊膏用松香型助焊剂活化点的研究

论述了无铅焊膏用松香型助焊剂活化点研究的重要性,探讨了活化点的物理意义及其影响因素.实验结果表明,无铅焊膏用松香型助焊剂的活化点就是松香树脂酸在有机溶剂中电离溶解平衡常数的升温曲线的拐点,松香种类对其活化点没有影响,决定其活化点的影响因素是松香本身的物理化学性质、溶剂以及有机酸的电离常数.     

光谱载体氯化锂对ICP-OES法测定铅锰的影响

为研究光谱载体LiCl对ICP-OES法测定Pb、Mn的影响,通过测定在不同LiCl浓度、射频功率、观测高度、载气流量和进样量条件下谱线Mn Ⅰ 279.482nm,Mn Ⅰ 403.075nm,Mn Ⅱ 257.610nm,Mn Ⅱ 259.372nm,Pb Ⅰ 217.000nm,Pb Ⅰ 283.306nm,Pb Ⅱ 220.353nm的净强度,得到了各谱线灵敏度的影响规律。证明LiCl是ICP-OES法测定Pb、Mn的良好光谱载体,LiCl增敏ICP-OES法测定地表水中Pb、Mn是可行的。