电化学法制备辛酸亚锡新工艺

采用电化学法代替传统的复分解法制备辛酸亚锡,研究了电解质、搅拌速度、电流密度、电压、温度、电极材料及抗氧化剂等诸多因素对辛酸亚锡产品质量的影响,并获得了最佳工艺参数。实验结果表明,在以浓度为 6 mol/L氯化钠为电解质、以金属锡为阳极、以钛板为阴极、阳极电流密度为100～120 A/m2、阴极电流密度为800～ 1 000 A/m²、搅拌转速为100 r/min、电解液温度为60～70 ℃,同时加抗氧化剂的情况下,可制备得到亚锡质量分数为28.32%、全锡质量分数为29.23%的辛酸亚锡产品。     

甘肃某含金多金属硫化矿金铅回收试验

对甘肃某含金多金属硫化矿石进行了浮选工艺技术条件研究。结果表明,采用1粗2精2扫、中矿顺序返回流程优先选铅,1粗2精2扫、中矿顺序返回流程选金,最终获得了铅品位为40.86%、铅回收率为93.13%、含金35.51 g/t、金回收率为36.74%的铅精矿,和金品位为8.94 g/t、金作业回收率为93.48%的金精矿,金的总回收率为95.88%。     

ICP-MS法测定保鲜薄膜中微量溶出铅镉的研究

采用电感耦合等离子体质谱(ICP-MS)法,用4％乙酸溶液萃取分离Pb,Cd,对保鲜薄膜表面微量溶出元素Pb和Cd进行了分析.对影响其测量的各种因素进行了较为详细的研究,确定了实验的最佳测定条件.结果表明,方法的检出限为:0.03(Pb)和0.02μg/L(Cd),回收率为94.4％～104.2％,RSD小于2.02％.该法准确、快速、简便,应用于保鲜薄膜中的微量溶出铅镉的测定,结果满意.     

安徽省市售大米铅、镉、汞污染状况及健康风险评价

测定安徽省市售大米中的重金属元素铅、镉、汞,评估其污染状况,并进行健康风险评价,为保障人们饮食安全提供科学依据。采用ICP-MS法[2,4],共检测了101份样品。其中铅检出率为40%,超标率为0;镉检出率为100%,超标率为0;汞检出率为69%,超标率为0。健康风险评价结果表明,安徽省市售大米中的铅、镉、汞对人体健康风险影响较小,镉对人体健康影响存在一定的风险。     

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.     

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…