浸金体系中影响硫脲消耗因素的研究

本文测定了硫化矿及其氧化焙砂对硫脲的吸附，空气对硫脲的氧化，以及Ｆｅ（Ⅲ）离子作氧化剂时，浮选剂黄、民泡剂松节油、硫化矿和焙砂对硫脲稳定性的影响。研究结果表明：硫化矿及焙砂对硫脲都有吸附作用；空气的氧化亦不容忽视；硫化矿的焙砂对硫脲－Ｆｅ（Ⅲ）离子之间的氧化还原反应均表现出显著的催化作用，而浮选药剂则几乎没有影响。在浸取体系中，苦有过量的Ｆｅ（Ⅲ）离子绝大部分转化为Ｆｅ（Ⅲ）离子，硫脲很不稳定，迅     

浅析炼铜密闭鼓风炉熔炼时Fe3O4的行为与控制

介绍了天马山硫砷金精矿焙砂制团替代转炉渣熔炼的方案概况，比较了焙砂与转炉渣中Ｆｅ３ Ｏ４ 含量的差异，研究分析了熔炼时Ｆｅ３ Ｏ４ 的行为机理、分配率及分配量，探讨了Ｆｅ３ Ｏ４ 控制的具体措施，得出了措施控制得当时，基本能消除焙砂中Ｆｅ３ Ｏ４ 对熔炼过程产生不良影响的结论。     

金属阳离子对含金黄铁矿浮选的影响及消除方法的研究

矿浆中难免的金属离子Ｃｕ＾２＋、Ｆｅ＾２＋、Ｆｅ＾３＋在达到一定浓度时，会严重抑制含金黄铁矿的浮选。腐植酸钠可用来络合Ｃｕ＾２＋、Ｆｅ＾２＋、Ｆｅ＾３＋完全消除这些金属离子对含金黄铁矿浮选的影响。     

废弃锰矿焙砂浸出液的铁,钴,锰分离研究

本文对四川省某地废弃锰矿焙砂浸出液进行了铁、钴、锰分离工艺研究。研究结果表明，用ＭｎＯ２作氧化剂，在溶液ｐＨ＝１￣２，温度１００℃，时间１ｈ，ＭｎＯ２用量为理论量的１．５倍的条件下，氧化了Ｆｅ＾２＋；氧化后控制溶液ｐＨ＝３．８￣４．１，用浓度为６￣７％的石灰乳液中和除铁，铁的去除率可达９８．０５％；除铁后的溶液控制ｐＨ＝４．５￣５．４，温度８０℃，用２０％Ｎａ２Ｓ溶液沉钴，Ｎａ２Ｓ的用量为理论量的     

高砷高硫金精矿固化焙烧-氰化浸出试验研究

介绍了高砷高硫金精矿矿物成分、固化焙烧-氰化浸出工艺条件，探讨了焙砂氰化浸出的机理。试验结果表明，金精矿经固化焙烧，焙砂氰化浸出时加入适量混合氧化剂(H2O2 KMnO4)和助浸剂G能显著提高金的浸出率，金浸出率为88．4％，砷、硫固化率均为90％。     

液膜法从湿法炼锌系统中提取镓的研究

对利用液膜法从湿法炼锌系统中分离提取镓的工艺进行了系统研究，确定了分离提取镓的最佳液膜条件。结果表明，在最佳条件下Ｇａ３＋的迁移率为９８５％，内水相可富集近１０００倍，Ｚｎ２＋、Ｃｕ２＋、Ｇｅ４＋及Ｆｅ３＋等杂质对Ｇａ３＋的迁移影响很小。     

液膜法从湿法炼锌系统是提取镓的研究

对利用液膜法从湿法炼锌系统中分离提取镓的工艺进行了系统研究，确定了分离提取镓的最佳液膜条件。结果表明，在最佳条件下Ｇａ＾３＋的迁移率为９８．５％，内水相可富集近１０００保，Ｚｎ＾２＋、Ｃｕ＾２＋、Ｇｅ＾４＋及Ｆｅ＾３＋等杂质对Ｇａ＾３＋的迁移影响很小。     

氟碳铈矿热分解行为的研究

采用ＸＲＤ法分析了不同温度下氟碳铈矿焙烧分解产物的组成，探讨了氟碳铈矿的热分解过程。试验结果表明氟碳铈矿的热分解是分步进行的。首先（Ｃｅ，Ｌａ）ＣＯ３Ｆ分解成（Ｃｅ，Ｌａ）ＯＦ；升高焙烧温度，（Ｃｅ，Ｌａ）ＯＦ发生相分解，生成Ｃｅ０．７５Ｎｄ０．２５Ｏ１．８７５和（Ｃｅ，Ｐｒ）Ｌａ２Ｏ３Ｆ３两相；随着焙烧温度的继续升高，（Ｃｅ，Ｐｒ）Ｌａ２Ｏ３Ｆ３可分解为ＬａＦ３、Ｃｅ２Ｏ３、ＰｒＯ１．８３等相。焙烧过程中Ｃｅ３＋、Ｐｒ３＋氧化为四价，没有明显的脱氟行为。     

用锌精矿作还原剂净液除铁

在９０～９５℃条件下，采用锌精矿作还原剂，经过４ｈ，可将硫酸酸性溶液中Ｆｅ￣（３＋）的８０％还原成Ｆｅ￣（２＋），用此溶液浆化锌焙砂，中性浸出澄清性好，能使生产正常进行。     

提高水洗效率的新途径

在水洗过程中，洗水中加入柠檬酸，使Ｆｅ＾３＋与柠檬酸络合，且抑制Ｆｅ＾３＋的水解，从而缩短了水洗时间，提高了水洗后偏钛到的铁含量明显降低。     

酸法浸铀过程中Fe3+与浸出铀之间关系的数值模拟

为探究酸法地浸过程中Fe³⁺作为氧化剂时铀的浸出情况，通过使用模拟软件PHREEQE建立模型，观察浸出液各组分的浓度及迁移变化，揭示氧化剂Fe³⁺与浸出铀之间的关系。结果表明：作为氧化剂的Fe³⁺促使铀矿的溶解及Fe²⁺的出现，随着铀的浸出结束，Fe³⁺的浓度趋于稳定；且铀矿的溶解速率与Fe³⁺、Fe²⁺的增长速率密切相关。Fe³⁺的浓度增长变快时，Fe²⁺的浓度增长及铀矿的溶解也加快；随着铀矿的溶解速率降为零后，Fe²⁺的增长速率也趋近于零，氧化剂Fe³⁺的增长速率也降为零。     

氯化钠-硫氰酸铵-正丙醇-水体系中铁（Ⅲ）的析相萃取分离和富集研究

研究了氯化钠-硫氰酸铵-正丙醇-水体系析相萃取分离和富集铁的行为及铁与一些金属离子分离的条件。结果表明,氯化钠能使正丙醇的水溶液分成两相,在分相过程中,Fe（Ⅲ）和NH4SCN生成的［Fe（SCN）4~6］［（4~6）-3］-与质子化正丙醇C3H7OH2+ 形成的缔合物［Fe（SCN）4-6］［ C3H7OH2］1-３能被正丙醇相完全萃取。当溶液pH值为3,正丙醇的体积分数、NH4SCN溶液的浓度和氯化钠溶液的质量浓度分别为30 %,7.0×10-2 mol/L和0.2 g/mL时, Fe（Ⅲ）的萃取率达到97.5%以上,而W(Ⅵ),Ag（Ⅰ）,Ce（Ⅲ）,Cr（Ⅲ）,Mn（Ⅱ）,Cd（Ⅱ）,Al（Ⅲ）,Ni（Ⅱ）,Ga（Ⅲ）和Mg（Ⅱ）基本不被萃取,实现了Fe（Ⅲ）与上述金属离子的分离。对合成水样和镍铬铝合金中Fe（Ⅲ）进行分离和测定,结果满意。该萃取体系可以用作微量铁的分离和富集,在分析中具有实用价值。     

释放螯合滴定法测定钼铁中的铁含量

用ＮＨ４ＳＣＮ、（Ｃ４Ｈ９）４ＮＣＩ为释放剂,选择性螯合一法测定钼铁中的铁。先用ＥＤＴＡ合Ｆｅ＾３＋和其他阳离子,然后加入ＮＨ５ＳＣＮ和（Ｃ４Ｈ９）４ＮＣＩ,分解Ｆｅ－ＥＤＴＡ螯合物、释放出的ＥＤＴＡ,用Ｉｎ（ＮＯ３）３标准溶液返滴定,而Ｆｅ＾３＋形成〖（Ｃ４Ｈ９）４Ｎ〗３〖Ｆｅ（ＳＣＮ）６】缔合物。实验结果表明,一般常见阳离子完全不干扰测定铁,该法已成功地用于测铁中的铁含量。     

H2O2-driven reduction of the Fe3+-quin2 chelate and the subsequent formation of oxidizing species

The objective of this study was to compare effects of quin2 and EDTA in iron-driven Fenton-type reactions. Seven different assays for detection of strong oxidants were used: the DMSO, deoxyribose, benzoate hydroxylation, and plasmid DNA strand breakage assays, detection of 8-oxo-deoxyguanosine in deoxyguanosine mononucleosides and calf thymus DNA, and electron spin resonance with the spin-trap (4-pyridyl-1-oxide)-N-tert-butylnitrone (4-POBN) in the presence of ethanol or DMSO. With H2O2 and Fe3+, quin2 generally strongly increased the formation of reactive species in all assays, whereas with EDTA the results varied between the assays from barely detectable to highly significant increases compared to H2O2 and unchelated Fe3+. We found that the species produced in the reaction between Fe3+-quin2 and H2O2 behaved like the hydroxyl radical in all assays, whereas with Fe3+-EDTA no clear conclusion could be drawn about the nature of the oxidant. The effect of quin2 on the formation of oxidants on Fe2+ autoxidation, varied from generally inhibiting to slightly promoting, depending on the assay used. EDTA had a promoting effect on the amount of oxidant detected by all but one assay. None of the autoxidation systems produced DMSO or ethanol radical adducts with 4-POBN. In the presence of either chelator, H2O2, and Fe2+ DMSO and ethanol radical adducts of 4-POBN were produced. Using the Fe2+ indicator ferrozine, evidence for direct reduction of Fe3+-quin2 by H2O2 was found. Superoxide anion radical appeared to be less efficient than H2O2 as reductant of Fe3+-quin2 as addition of superoxide dismutase in the ferrozine experiments only decreased the amount of Fe2+ available for Fenton reaction by 10-20%. The main conclusions from our study are that the reduction of Fe3+-quin2 can be driven by H2O2 and that Fe2+ in the following oxidation step produces a species indistinguishable from free hydroxyl radical.     

锑金精矿酸性电积工艺中电解液中总铁、Fe2+、Fe3+的含量测定

铁的存在对锑金精矿浸出至关重要,某公司锑金精矿电积工艺中Fe³⁺和Fe²⁺共存,为了准确测定总铁、Fe²⁺和Fe³⁺含量,有效指导生产,通过研究,使用简单的铈量法能解决这一问题。此方法操作简单,可快速准确地测量出电解液中的总铁、Fe²⁺和Fe³⁺含量。     

选择性磷酸沉淀分离铬铁的新工艺

针对酸性水溶液中铬铁分离难题,基于Fe3+还原预处理,提出选择性磷酸沉淀铬分离铬铁的方法。研究沉淀剂Na₃PO₄用量、溶液初始pH值、反应温度及保温时间等对铬铁分离的影响,所得较优工艺条件为:溶液初始pH值为2.0,按PO₄3-/Cr3+摩尔比0.375的量加入Na₃PO₄,90 ℃保温60 min。在上述条件下,铬沉淀率可达98.53%,铁沉淀率仅1.42%,分离效果理想。实验还证明,该方法适用于较宽的铁浓度范围,而且Cu2+、Zn2+、Ni2+及Cl-等杂质离子对选择性沉铬无明显干扰。该方法为含铬物料的铬分离提取提供了一条新的可选途径。      

Distribution of Ca2+-dependent protein kinase C isoforms in the suprachiasmatic nucleus of the diurnal murid rodent, Arvicanthis niloticus

The suprachiasmatic nuclei (SCN) contain the major 'biological clock' in mammals that controls most circadian rhythms expressed by these animals. The functional importance of protein phosphorylation and intracellular Ca2+ in the mammalian circadian pacemaker is becoming increasingly apparent. Here we report the immunocytochemical localization of the four Ca2+-dependent protein kinase C (PKC) isoforms (alpha, betaI, betaII, gamma) within the SCN of the diurnal murid rodent, Arvicanthis niloticus, and the nocturnal golden hamster. In the SCN of A. niloticus, PKCalpha was the most abundant of the four isoforms. Cells containing PKCalpha were homogeneously distributed throughout the SCN. PKCbetaI cells were sparsely distributed in the perimeter of the SCN and were absent in its central area. PKCbetaII and -gamma were not found in the SCN of A. niloticus. In the SCN of the golden hamster, PKCalpha cells were most heavily concentrated in the dorsomedial region, though some were also present laterally and ventrally. The distribution of arginine-vasopressin (AVP) cells in the SCN overlapped with that of PKC in both species. Species differences in the location of the Ca2+-dependent PKC isoforms suggest differences in function such as the relaying of photic or non-photic information to the clock mechanism, or the synchronization of AVP neurons and their subsequent output signals.     

Carvedilol inhibition of lipid peroxidation. A new antioxidative mechanism

To define the molecular mechanism(s) of carvedilol inhibition of lipid peroxidation we have utilized model systems that allow us to study the different reactions involved in this complex process. Carvedilol inhibits the peroxidation of sonicated phosphatidylcholine liposomes triggered by FeCl2 addition whereas atenolol, pindolol and labetalol are ineffective. The inhibition proved not to be ascribable (a) to an effect on Fe2+ autoxidation and thus on the generation of oxygen derived radical initiators; (b) to the scavenging of the inorganic initiators O2*- and *OH; (c) to an effect on the reductive cleavage of organic hydroperoxides by FeCl2; (d) to the scavenging of organic initiators. The observations that (a) carvedilol effectiveness is inversely proportional to the concentration of FeCl2 and lipid hydroperoxides in the assay; (b) the drug prevents the onset of lipid peroxidation stimulated by FeCl3 addition and; (c) it can form a complex with Fe3+, suggest a molecular mechanism for carvedilol action. It may inhibit lipid peroxidation by binding the Fe3+ generated during the oxidation of Fe2+ by lipid hydroperoxides in the substrate. The lag time that carvedilol introduces in the peroxidative process would correspond to the time taken for carvedilol to be titrated by Fe3+; when the drug is consumed the Fe3+ accumulates to reach the critical parameter that stimulates peroxidation. According to this molecular mechanism the antioxidant potency of carvedilol can be ascribed to its ability to bind a species, Fe3+, that is a catalyst of the process and to its lipophilic nature that concentrates it in the membranes where Fe3+ is generated by a site specific mechanism.     

循环伏安法测定溶液中Fe3+和Fe2+浓度比

采用循环伏安法（CV）测定铁泥制备Fe3O4过程中Fe3+与Fe2+浓度比值的变化,为该工艺过程提供方便、快捷的监测方法。在实验条件下,溶液中的Fe3+与Fe2+组成可逆的氧化还原体系,产生一对峰形良好的氧化还原峰。对影响峰电流的扫描速度、pH值及干扰离子等因素进行考察,结果表明,扫描速度在0.002~0.01 V/s、pH在1.5~2.5时对氧化峰电流及还原峰电流没有影响;溶液中存在的SO42-离子在实验范围内对体系基本无干扰。Fe3+的浓度在0.000 8～0.008 4 mol/L呈线性关系,相关系数为0.999 9,相对标准偏差(n=7)在 0.70%~2.0%之间。该法与标准重铬酸钾滴定法对比,相对误差为1.7%。