Evaluation of ammonium thiosulfate as a soil urease inhibitor

Interest in use of ammonium thiosulfate (ATS) in conjunction with urea as a fertilizer has been stimulated by recent reports that this compound retards hydrolysis of urea by soil urease and thereby reduces volatilization of urea N as ammonia from soils fertilized with urea. We evaluated ATS as a soil urease inhibitor by studying its effects on urea hydrolysis, seed germination, and early seedling growth in soil. We found that ATS significantly retarded urea hydrolysis only when applied at rates as high as 2,500 or 5,000µg g^–1 soil, whereasN-(n-butyl) thiophosphoric triamide (NBPT) (a patented inhibitor of urea hydrolysis in soil) caused substantial retardation of urea hydrolysis when applied at rates as low as 1µg g^–1 soil. We also found that ATS had an adverse effect on germination of corn or wheat seeds in soil when applied at the rate of 2,500 or 5,000µg g^–1 soil and caused a dramatic reduction of early seedling growth of corn or wheat when applied at the rate of 1,000, 2,500, or 5,000µg g^–1 soil. These findings indicate that ATS has little, if any, potential value for retarding hydrolysis of urea fertilizer in soil.     

催化氧化法生产硫代硫酸钠

用镍盐(NiSO4)催化空气氧化二硫化钠生产硫代硫酸钠,在室温下就可以快速完全氧化。与传统工艺相比,具有污染少、能耗低、质量稳定和操作方便等优点。     

金、银选冶联合流程中粗硒的测定

在9mol／L HCl介质中,用无水亚硫酸钠溶液将Se^4 还原成Se^0;被还原的硒经酸溶解后,在0．8mol／L HCl介质中,直接用硫代硫酸钠标准溶液滴定。该方法测定硒的范围为30％～90％,标准偏差为0．070％～0．098％,相对标准偏差为0．07l％～0．19％。该方法具有选择性高,稳定性好,准确度可信,测定范围广等优点。     

Review: Removal of Thiosalt/Sulfate from Mining Effluents by Adsorption and Ion Exchange

Thiosalts are generated as intermediate products in the oxidation of sulfide ores. Thiosalts have relatively low toxicity, however sulfate formed from the degradation of thiosalts, leads to pH depression in receiving water bodies creating toxic conditions for aquatic organisms. Therefore, proper management and treatment of mining effluent water containing thiosalts is critical. This article briefly discusses Acid Mine Drainage (AMD), different sulfur species present in AMD, behavior of thiosalts as a function of pH and temperature, and thiosalt treatment methods including natural degradation, chemical, and biological oxidation. Carbonaceous adsorbents, ion-exchange resins and other adsorbent approaches are discussed in detail.     

Na_2S_2O_3对镍钴电池负极材料电化学性能的影响

通过向镍钴电池的电解液中加入不同浓度Na_2S_2O_3,并研究了其对镍钴电池负极材料电化学性能的影响,采用SEM和XRD分析了沉淀产物的微观形貌和结构。结果表明,通过对钴电极的充放电性能测试发现,当Na_2S_2O_3浓度为0.04mol/L时,Co电极的最大放电容量高达411.1mA·h/g,当Na_2S_2O_3浓度0.02mol/L时,Co电极的循环稳定性最好,其容量保持率为86.16%,比未加Na_2S_2O_3时的容量保持率高出30.71个百分点。结合循环伏安特性曲线(CV)和交流阻抗图谱(EIS)分析得知,Na_2S_2O_3能够有效抑制CoOOH的形成,提高活性物质的利用率,从而实现放电容量和循环稳定性的提高。     

硫代硫酸盐浸金体系中活性炭表面Zeta电位研究

研究了硫代硫酸盐浸金体系下基底试剂浓度与pH值、模拟浸出液pH值与搅拌时间等对活性炭表面Zeta电位的影响。结果表明,活性炭零电点为2.13; 其表面Zeta电位随硫代硫酸盐浓度增加而负值减小,随硫酸铜浓度增加而正值减小,随氨水浓度增加保持不变; 氨水溶液pH值大于9.0时,活性炭Zeta电位开始负值增大; 而活性炭Zeta电位几乎不随硫代硫酸盐溶液pH值变化而变化。模拟浸出液中,活性炭表面Zeta电位随pH值、搅拌时间变化较小; 当pH值为9.0时,活性炭对Au(S₂O₃)₂^3-的吸附率最大,为27.8%。模拟浸出液中活性炭表面主要优先吸附了含硫含氮化合物,表面Zeta电位始终为负值,活性炭通过静电作用难以吸附Au(S₂O₃)₂^3-。     

贵州某微细浸染型金矿硫代硫酸盐浸出试验研究

贵州某微细浸染型金矿金品位为3.46 g/t, 在原矿性质分析的基础上, 采用硫代硫酸盐直接浸出工艺, 进行了探索试验、条件试验和综合优化试验, 确定了合理的浸出条件为: Na₂S₂O₃·5H₂O用量0.4 mol/L, CuSO₄用量4 g/L, NH₃·H₂O用量4 mol/L, Na₂SO₃用量0.3 mol/L, 液固比为4∶1, pH为9.5。将原矿直接浸出与预处理后试样浸出进行对比试验, 获得金浸出率分别为72.10%和85.09%, 并对两者浸出率差异进行了分析。     

硫代硫酸盐浸金过程中添加剂的作用研究进展

硫代硫酸盐是一种具有潜力的金银浸出剂,但是硫代硫酸盐在浸金体系中容易氧化分解,增加药剂成本。添加剂的加入可以有效缓解这一问题,同时改善浸金环境,促进金的浸出。评述了硫代硫酸盐浸金过程中常见的几种添加剂的作用,并对今后的发展及应用进行了展望。     

氨性硫代硫酸盐浸出金银过程中降低硫代硫酸盐消耗量研究进展

氨性硫代硫酸盐浸出金银过程中硫代硫酸盐消耗量大是阻碍该技术应用于工业生产中的主要因素之一。浸出体系中铜离子和铜氨络离子浓度是影响硫代硫酸盐消耗量的关键因素,通过控制铜离子和铜氨络离子的浓度、加入添加剂或预处理矿石均可达到降低硫代硫酸盐消耗的目的。     

硫代硫酸盐浸金中硫代硫酸盐稳定性研究状况

阐述了硫代硫酸盐浸金过程中保持浸金试剂稳定性的主要方法,包括标准氨性硫代硫酸盐浸金体系的改进和非铜氨体系。标准氨性硫代硫酸盐浸金体系的改进主要通过加入螯合剂控制溶液中铜氨络离子的浓度、控制溶解氧、改变溶液离子强度和加入相关硫氧化合物等方式,非铜氨体系主要讨论了铁螯合物,同时概括了研究发展趋势。