硫脲浸金新进展

综述了最有希望取代氰化法浸金的硫脲法近年来的研究进展。酸性硫脲法存在硫脲过多消耗、设备严重腐蚀、溶金没有选择性、以及溶液的再生和净化工序复杂等一系列问题。为克服这些缺点，笔者从硫脲本身的微观结构出发，根据“构效关系”找到了一种能使硫脲在碱性介质中稳定的稳定剂，并对碱性硫脲浸金工艺及其基础理论进行了系统深入的研究，此工艺在含金废料的回收及金矿的浸取中取得了满意的效果，是一条经济合理、简单可行的提金新途径。文中最后指出了碱性硫脲法浸金尚待解决的问题，并展望了其发展前景。     

某金矿石浮选-硫脲炭浸综合回收金银铜硫的工艺试验研究

阐述了采用浮选－－硫脲炭浸一步法处理铜硫砷含量高的某难选金矿石的工艺。工艺的试验结果体现了联合流程处理难选金矿石的优势。     

Adsorption of 1,1,3,3-tetramethyl-2-thiourea on the mercury electrode: dependence on the concentration of the base electrolyte

Adsorption of 1,1,3,3-tetramethyl-2-thiourea (TMTU) on a mercury electrode from 1, 0.5, and 0.1 M NaClO₄ is described by means of the adsorption isotherms constants calculated from the surface pressure as a function of electrode charge density and adsorbate bulk concentration. The adsorption parameters for the double-layer were calculated based on the data from the differential capacity-potential curves. The values of the relative surface excess increase with an increase in the concentration of NaClO₄. In each system studied, significantly smaller values of Γ_S for σ_M<0 were obtained, compared with the corresponding values for σ_M≥0. At positive values of σ_M, the values of ΔG° obtained from either the Frumkin or the Flory-Huggins isotherm are similar. However, the values of the parameter A obtained from the Flory-Huggins isotherm are lower.The dependence of Φ^M−2 on the relative surface excess at a constant charge density is nonlinear. The rectilinear segments of these dependences obtained for smaller values of Γ′ were analyzed in order to calculate the electrostatic parameters of the inner layer.     

镧(Ⅲ)与硫脲配合物的合成、表征及抗菌活性研究

本文报道了配合物 L a I3 · 2 CS(NH2 ) 2 · 10 H2 O的新的合成方法 ,通过元素分析、X射线粉末衍射、红外光谱、核磁共振谱、质谱、差热—热重分析 ,确定了配合物的组成和结构 ,首次测定了配体和配合物的抗菌活性。     

Urea, thiourea and guanidine derivatives as multifunctional fuel stabilisers

Different N-substituted derivatives of urea, thiourea and guanidine have been synthesised and characterised for structural information by FT-IR and ¹³C NMR spectroscopy. Accelerated stability tests have been done to evaluate their sediment inhibition and dispersant characteristics on distillate fuels containing high proportions of unstable components and results discussed. It is inferred that urea and guanidine derivatives not only inhibit the reactions responsible for sedimentation in the test fuel but also effectively disperse the gum and sediment formed. It is concluded that the nature of substituents on the central carbon atom and on the amino groups determines the performance behaviour of these compounds.     

Novel imino diacetamide grafted styrene divinyl benzene resin for separation and recovery of palladium from simulated high level liquid waste

Imino diacetamide styrene divinyl benzene resin was evaluated for separation of palladium from simulated high level liquid waste (HLLW). The kinetics of sorption was found to be fast, and the kinetic data were fitted well to the pseudo-second-order kinetics model. Very high K_d (~10³) were obtained for Pd for feed solutions having acidity from 0.25 M to 4.0 M HNO₃. The loading studies of the resin showed the maximum sorption capacity of 54 mg/g. Back extraction studies showed that sorbed Pd can be effectively back extracted using 0.01 M thiourea in 0.2 M HNO₃. Studies with simulated HLLW showed preferential sorption of Pd over other metal ions.     

Magnetically separable nano CuFe2O4: an efficient and reusable heterogeneous catalyst for the green synthesis of thiiranes from epoxides with thiourea

The magnetically separable nano CuFe₂O₄ was prepared and used as an efficient heterogeneous catalyst for conversion of various epoxides to the corresponding thiiranes with thiourea in refluxing ethanol. The reactions were completed within 34?45 min to give thiiranes in 80?95% yields. The utilized nano CuFe₂O₄ can be reused for several times without losing its activity.     

废旧手机电路板硫脲提金的预处理工艺对比

分别采用硝酸和生物浸出对废旧手机电路板颗粒样品进行预处理,然后在硫脲浓度12g/L、Fe2(SO4)3质量分数0.3%、溶液pH=1.5、30℃条件下进行提金试验,从金浸出率、金属杂质浸出率和环境影响等方面对这两种预处理工艺进行评估。结果表明,硝酸氧化预处理—硫脲提金工艺在金属除杂效率方面有较大优势;而生物浸出—硫脲提金工艺的优势主要体现在生产成本和环境影响等方面。     

硫脲-亚硫酸体系中金电极的电化学动力学研究

采用Tafel曲线的电化学测试方法 ,研究了有无亚硫酸存在时 ,金电极在硫脲体系阳极过程的动力学。试验结果表明 ,硫脲浓度的增加可以提高金电极的腐蚀电流密度 ,有无亚硫酸时 ,金在硫脲体系溶解的活化能分别为5 9.11kJ/mol和 48.47kJ/mol。理论计算表明 ,在 2 5℃下 ,添加 5× 10 - 6 mol/L的亚硫酸可使硫脲阳极氧化速率提高73 .3倍。而在有无亚硫酸存在时 ,体系温度由 2 98K提高至 3 2 3K ,金在硫脲体系中的阳极溶解速率分别提高 4.5 5倍和 6.3 7倍     

硫脲浸金过程选择氧化剂的热力学判据研究

本文从热力学角度提出：只要氧化剂的氧化电位大于＋０．３８Ｖ，硫脲浸金反应在热力学上就可能发生，否则硫脲浸金过程不可能顺利地进行。这为硫脲浸金工艺氧化剂的选择指明了方向，同时比较和分析了硫脲和氰化物浸金的热力学判据和相关参数。