Nanoparticles of silver powder obtained by mechano-chemical process

The silver (Ag) powder was synthesised in a mechano-chemical (MC) process by inducing a solid-state displacement reaction between silver chloride (AgCl) and copper (Cu). The AgCl and Cu were ground in atmosphere conditions using a planetary ball mill. The reaction caused the mixture of AgCl and Cu to change the composition of the mixture, such as Ag and copper chloride (CuCl). CuCl was separated from MC product by leaching with ammonium hydroxide and we obtained Ag powder as the final product. Moreover, ascorbic acid (C₆H₈O₆) was used as the additive to improve dispersion of Ag powder during MC process. The ground powders, formed in the presence of additive, were characterised by X-ray diffraction (XRD) and scanning electron microscope (SEM). The XRD determined that the reaction between AgCl and Cu was complete in almost all the experiments carried out. SEM examinations revealed that the size of the particles in the synthesised metallic Ag powder was in the range of 30–300 nm.     

空心玻璃微珠化学镀银的研究

本文用甲醛-银氨溶液,对3～10微米的空心玻璃微珠进行化学镀银,制备出了吸波用银包覆空心玻璃微珠粉体,并探讨了pH值、稳定剂及装载量对微珠化学镀银的影响.微珠粉末中银含量的测定和SEM观察结果表明,通过增加镀液中NaOH的含量、提高镀液的pH值,能够增加镀液中的银析出量,微珠表面的银包覆较为致密连续;稳定剂可阻止镀液的自分解,但会导致表面包覆层不致密;通过调整空心玻璃微珠的装载量,能够调节表面包覆银颗粒的粒径大小,控制镀银层的厚度,同时增加装载量,也能减少自分解现象.     

首饰用抗变色银合金研究进展

简要分析了银合金变色的原因.评述了表面处理以及贵金属合金化、贱金属合金化、稀土合金化等方法以提高银合金抗变色性能的特点.并着重介绍了当前研究最多的贱金属合金化法制备的典型银合金成分及其抗变色机理.     

Comparative Antimicrobial Activity of Silver Nanoparticles Obtained by Wet Chemical Reduction and Solvothermal Methods

The synthesis of nanoparticles from noble metals has received high attention from researchers due to their unique properties and their wide range of applications. Silver nanoparticles (AgNPs), in particular, show a remarkable inhibitory effect against microorganisms and viruses. Various methods have been developed to obtain AgNPs, however the stability of such nanostructures over time is still challenging. Researchers attempt to obtain particular shapes and sizes in order to tailor AgNPs properties for specific areas, such as biochemistry, biology, agriculture, electronics, medicine, and industry. The aim of this study was to design AgNPs with improved antimicrobial characteristics and stability. Two different wet chemical routes were considered: synthesis being performed (i) reduction method at room temperatures and (ii) solvothermal method at high temperature. Here, we show that the antimicrobial properties of the obtained AgNPs, are influenced by their synthesis route, which impact on the size and shape of the structures. This work analyses and compares the antimicrobial properties of the obtained AgNPs, based on their structure, sizes and morphologies which are influenced, in turn, not only by the type or quantities of precursors used but also by the temperature of the reaction. Generally, AgNPs obtained by solvothermal, at raised temperature, registered better antimicrobial activity as compared to NPs obtained by reduction method at room temperature.     

{100}面明胶-氯化银扁平颗粒乳剂研究进展

高氯化银{100}面扁平颗粒(T-颗粒)乳剂结合了高氯化银乳剂和T-颗粒乳剂的独到优势,在当代传统照相与数字影像强烈竞争的时期,它的制备与研究有助于提升传统银盐感光材料的竞争力。本文综述了高氯化银{100}面T-颗粒乳剂的制备原料、制备工艺过程、化学增感、光谱增感及该乳剂的应用前景。     

铅银渣氯化浸出液净化及有价金属回收试验

采用净液-置换工艺处理铅银渣氯化浸出液并提取银、铅,重点研究了铅粉置换银、铁粉置换铅的工艺影响条件。结果表明:利用Fe~(3+)易水解的特性,采用中和除铁,石灰调节溶液pH为4.0即可完全除铁,铅粉加入量为6 g/L,pH=1.5～2.5,温度60℃,置换时间40～60 min,在此条件下,银的置换率大于98%,溶液中残银浓度低于1 mg/L;两段逆流可以较完全置换出溶液中的铅,两段综合置换率为87.08%,最终置换产物含铅量90%,满足精炼要求。     

超声协同光催化还原法制备Ag/TiO2光催化剂及其活性研究

在光催化还原反应体系中引入超声场制备了Ag/TiO2光催化剂.考察了超声频率、功率等对还原反应的影响,对所制得的负载型Ag/TiO2光催化剂进行微观性能表征,并以低浓度苯酚溶液为降解对象进行光催化氧化活性表征.结果表明,超声场的引入对光催化还原反应有很好的强化作用,促进光催化还原反应的最佳超声频率为45 kHz,同时,Ag 还原率随着超声功率的增加而增大.所制得的Ag/TiO2光催化剂具有粒径小、光催化活性高的特点.     

从锰银共生氧化矿中提取锰、银工艺研究

研究了用硫铁矿作还原剂,在酸性条件下浸出锰银氧化矿。结果表明:锰浸出率大于92.5%,浸出液可用于制备工业碳酸锰(锰质量分数45.71%);银留在浸锰渣中,通过重选+浮选可回收过量硫铁矿;对重选细渣和浮选尾渣氰化浸出银,银浸出液以锌粉置换产出银泥(银质量分数92.18%);全流程锰、银回收率分别为88.42%和86.25%。     

纯银含银量分析方法的误差及改进

本文研究现有分析方法的误差及改进方法．ＮａＣｌ溶液的加入量使用称重法．消除了移液管加液的偶然误差,用电位滴定法代替比浊法,原子吸收法消除了氯化银部分溶液造成的系统误差．新分析方法具有较高的精密度．     

我国铜阳极泥分银渣综合回收利用研究进展

分银渣是铜阳极泥处理工艺的尾渣,其中含有多种有价金属锡、铅、铋、锑等,1 t阳极泥一般产生0.5～0.6 t分银渣。本文综述了国内处理分银渣提取有价金属的工艺流程,对分银渣回收的前景进行了展望,同时为探索一种环保型、高效型处理分银渣的工艺提出了相关建议。