铁回收镀银废液中的银

一、概述镀银废液中银的回收方法有四种:硫化物沉淀法;锌还原法;次氯酸钠法;电解法。本文介绍用铁来还原制取银,所用原料仅铁片、盐酸、硫酸。镀银废液及镀件漂洗液一般用电解法来提取金属银。如果用盐酸沉淀氯化银,蒸馏水洗涤沉淀,就能得到较纯的氯化银。如配氰化镀银槽,经氰化钾络合即     

氯化银废液中银的回收

硝酸银的回收方法很多,但往往由于工厂实验室条件和辅助药品的费用关系,使银的回收工作感到困难。为了工作方便和降低回收时所用辅助药品的费用,可以在氯化钠溶液中,用漂净的铁棒或铁片来还原氯化银为金属银。这个方法是根据金属表面的不均一性。在同一电解质溶液中,其表面上相邻的两个区域具有不同的电极电位,而构成了局部的微电池。     

银的回收

在含银的溶液内搅拌下注加盐酸(比重1.19工业用),直到不再析出白色乳状的氯化银沉淀为止。在沉淀沉降后倾泻出母液,用水洗涤(倾泻)沉淀到完全除去铁离子和氯离子。为了把洗涤过的氯化银沉淀还原成金属银,在适当容积的容器内用稀硫酸(1:4)和金属锌(棒状的)处理。直到沉淀内不再有白色的粒子时,还原便已完全。所析出的暗灰色细的金属银沉淀仔细用水洗涤(倾泻)到除去游离酸和锌离子,将洗涤过的银沉淀烤干,并在耐火土或最好在石墨坩埚内熔融以得出金属渣。也可不用熔融的方法,而将洗     

玻璃镀银新法

玻璃镀银的过程是以从银氨络化物中还原银离子为金属银作根据的。此时除有金属银薄层在玻璃表面出现之外,同时一部份银呈粉末状出现在溶液中。镀银溶液中银的利用率就取决于这两种还原银的比率。В.М.Винокуров氏认为镀在镜上的银,总是比被还原在溶液中的银少得多。无论那一种已有的镀银方法,都不能有效地利用在镀银溶液中的银,而大部份的银成为所谓“废银”留于溶液中。镜上银子的析出率依一系列的因素而转移:主要是还原剂的特性,溶液的温度,硝酸银的浓度和镀银溶液中其他组份,以及在     

提高氯化银沉淀法回收银得率的探讨

以化学沉淀法回收银时,由于沉淀形式的不同,有硫化银沉淀法、氢氧化银沉淀法及氯化银沉淀法.在需要回收银的溶液里,除银离子外,通常还有铜、锌、铅、铬等金属离子.在进行硫化银沉淀或氢氧化银沉淀时,如不将这些金属离子与银离子事先分离,这些金属离子就会与银离子共同沉淀.而氯化银沉淀法是以氯离子与银离子生成氯化银沉淀的特征反应为基础的.除汞离子外,溶液中其它金属离子不与氯离子发生沉淀反应.所以,以氯化银沉淀法回收银时,可以不必事先将其它金属离子分离.采用氯化钠为沉淀剂,价格不仅比硫化钠便宜,而且又没有臭味.对于工业废水中氯化物含量的排放标准,又较硫化物要宽,不必增加治理氯化物的环保设施.通过综合比较,可见氯化银沉淀法要比硫化银沉淀法、氢氧化银沉淀法优点较多.     

从氯化银废液中回收金属银、再制硝酸银

我们遵照毛主席“综合利用大有文章可做”的伟大教导,开展对原盐化验分析废液的综合利用。从废液氯化银沉淀中提炼出拿属银(每十克氯化银可提炼出金属银七克左右),又用金属银再制成硝酸银。我们岱山盐区每年用于原盐定等收购,出场和科学实验的化验分析用硝酸银达五公斤左右。如全部收集,可以得到四公斤左右的氯化银,从中可提炼出三公斤左右的金属银。银是国家贵重物资,开展这项综合利用,对于支援社会主义建设有着一定意义。     

高校化学实验废液中银的提取

在含银废液中加入氯化钠生成氯化银沉淀,然后用氢氧化铵溶解沉淀,再用水合肼还原,制得单质银。提取的银粉的纯度是用佛尔哈德法测定的。实验结果表明:银的回收率为91.11%,纯度为96.11%,结果满意。并探讨了氢氧化铵溶解氯化银的最佳配比。     

银的快速还原法

从银的废渣中收回银的实用方法需要很长的时间。现在提出利用二价铬从无机的废渣中收回银的方法。用二价铬离子将氯化银还原成金属银只须5—10分钟。用 HC1 使硫氰化银和铬酸银转变为氯化银,然后在 AgCl 沉淀中加入 CrCl_2或CrSO_4液。分离出的金属银用水洗到除去 Cl-为止,然后溶解于 HNO_3(1:1)中,再在水浴上将     

CODcr测定废液中银的回收与利用

对重铬酸钾法测定CODCr的废液组成进行了估算,提出了以氯化银沉淀形式收集CODCr废液中的银离子,用Zn-H2SO4体系还原氯化银沉淀的方法,采用该方法可得到纯度为99.6%的金属银粉,回收率为94.8%,回收的银粉可用于CODCr的分析。回收银后的废液在碱性条件下加过量硫化钠生成硫化铬、硫化亚汞和硫化亚铁共沉淀,达到去除Cr3+,Hg2+和Fe3+的目的,清液可排放。     

用锌还原法从氯化银中提取银

本文讨论了采用锌还原法从含氯化银废液当中提取银,而后再将银转化为硝酸银溶液,并计算出其产率和纯度。     

从含银实验废液中回收银并制备硝酸银

采用高温还原法回收实验废液中的银(回收率达98%以上,回收银纯度达99.90%),然后溶于硝酸,制备实验用试剂—硝酸银。硝酸银的回收率为97.5%。     

不同Br~-浓度下铂电极上镀银层的氧化动力学

本文采用循环伏安法研究了镀银铂电极在溴化钾溶液中的成核过程及氧化动力学,结果表明:AgBr的形成包括三个步骤,首先在银表面某些吸附Br~-的特殊位置上以平面方式成核,然后经过二个三维的成核步骤。在较低浓度的KBr溶液中,AgBr的形成由溶液中的Br~-迁移控制。在较高浓度的溶液中,由于生成的AgBr膜是高度松散的,速度控制步骤转化为在膜孔内Br~-的迁移。随着AgBr的生成以及AgBr的溶解沉积作用,膜孔被堵塞,同时反应速度转化为由AgBr膜中的Ag~+迁移控制。电镜结果也支持了以上结论。     

载银活性炭的载银量分析

采用灼烧法预处理，银量法滴定来测定载银活性炭的载银量，获得稳定而准确的分析结果。结果表明，制备载银活性炭时所加入的银并未全部吸附在活性炭上；吸附性能高的活性炭能制得高载银量的载银活性炭。     

Effects of Silver on Barium Titanate as a Function of Stoichiometry

This work examines the effects of Ag on stoichiometric and nonstoichiometric BaTiO₃ in terms of the unit cell dimensions, the polycrystalline microstructure, and the dielectric properties. Stoichiometric BaTiO₃ and compositions with 0.5 mol% TiO₂ excess and 0.5 mol% BaO excess were prepared via solid-state synthesis with varying amounts of Ag up to 0.3 mol%. Experimental results indicate that stoichiometry plays a significant role in the solubility of Ag and its effects on the physical properties. Overall, the solubility of Ag was negligible in stoichiometric BaTiO₃. However, compositions with excess TiO₂ stabilized the solubility of Ag as evidenced from changes in the unit cell dimensions and dielectric properties. Based on these data, it is proposed that Ag occupies the A-site in the perovskite structure with an upper limit of Ag solubility of 0.06 mol% Ag in BaTiO₃ with 0.5 mol% excess TiO₂. Dielectric measurements showed that Ag concentrations approaching 0.3 mol% gave rise to an increase in the space charge effect, especially at temperatures above T _C. In both nonstoichiometric compositions, the presence of a liquid Ag phase during thermal processing was found to affect microstructural development and sintering.     

Green Formation of Spherical and Dendritic Silver Nanostructures under Microwave Irradiation without Reducing Agent

The rapid and green formation of spherical and dendritic silver nanostructures based on microwave irradiation time was investigated. Silver nanoparticles were successfully fabricated by reduction of Ag(+) in a water medium and using polyvinylpyrrolidone (PVP) as the stabilizing agent and without the use of any other reducing agent, and were compared with those synthesized by conventional heating method. UV-vis absorption spectrometry, transmission electron microscopy (TEM), atomic absorption spectroscopy (AAS) and photon correlation spectroscopy (PCS) measurements, indicated that increasing the irradiation time enhanced the concentration of silver nanoparticles and slightly increased the particle size. There was a lack of large silver nanoparticles at a high concentration, but interestingly, the formation and growth of silver dendrite nanostructures appeared. Compared to conventional heating methods, the silver nanoparticle suspension produced by irradiated microwaves was more stable over a six-month period in aqueous solution without any signs of precipitation.     

无机抗菌磷酸盐玻璃及其性能的研究

采用高温熔融法,在磷酸盐玻璃的配合料中引入抗菌剂硝酸银,一次烧制而成制得抗菌玻璃材料,对磷酸盐玻璃的抗菌性能和缓释性能进行分析.结果表明:制备抗菌磷酸盐玻璃时,合适的银质量分数为1.5%～2.0%,处理温度在1200～1350℃,即获得良好的抗菌效果和缓释性.     

从卤化银废液中回收银并制备硝酸银标准溶液

利用铁与浓盐酸反应产生的H2与AgCl、AgI废液反应，可得到粗制银粉；将粗制银粉与硝酸反应转化成硝酸银后，加入紫铜，制得99．99％以上的纯银粉；再用纯银粉制备硝酸银标准溶液，从而实现了卤化银废液的有效回收。     

紫外光固化聚氨酯基导电银浆的制备及其性能研究

以超细球银与片状银粉复配作为导电相,二官能度的端乙烯基聚氨酯丙烯酸酯预聚物作为粘结相,制备出高电导率、高附着力和高柔韧性的紫外光固化聚氨酯基导电银浆。研究了超细球银与片状银粉的相对用量对银浆电导率、附着力和耐弯折性能的影响,并通过扫描电镜对银浆中银粉的分散状态进行了分析。结果表明:采用适量的超细球银与片状银粉复配,可以有效提高银浆的电导率和力学性能。当超细球银用量为6.6%(wt),片状银粉用量为65%(wt)时,银浆的电导率高达1.33×106S/m;与聚对苯二甲酸乙二醇酯基材具有良好的附着力,百格测试级别为5B;耐弯折性能优良,10次弯折测试后,电导率仍能达到3.38×105S/m。     

Ethene/Ethane (C2H4/C2H6) Separation through an Inorganic–Organic Hybrid Membrane Containing Silver(I) Ions as Olefin Carriers, Using Poly(N-vinylpyrrolidone) as a Mediation Agent

Novel inorganic–organic membranes that contained Ag⁺ ions as olefin carriers were prepared using sol–gel and dip-coating processes. The permeance of the membranes for nitrogen, helium, ethane (C₂H₆), and ethene (C₂H₄) were evaluated using the single-gas permeation method at temperatures of 298, 373, and 423 K. The results showed that the selectivity of the membranes to C₂H₄ against C₂H₆ increased as the measurement temperature increased, because the decomplexation rate of C₂H₄ molecules from Ag⁺ sites is enhanced by increases in the temperature. Fourier transform infrared spectrophotometry of the hybrid membranes and the performance of the membranes at 373 and 423 K indicated that poly( N -vinylpyrrolidone) (PVP) had a role in increasing the flexibility of the inorganic network and also served as a mediation agent to fix Ag⁺ ions in the polymer segments, because of the coordination interaction between the Ag⁺ ions and the PVP.     

Silver nanoparticles enhanced luminescence and stability of CsPbBr3 perovskite quantum dots in borosilicate glass

Series of silver nanoparticles (NPs) embedded CsPbBr₃ quantum dots (QDs) glass was synthesized via the melt-quench method. Ag NPs and CsPbBr₃ QDs coexist in the TEM image of the Ag-doped glass sample. Photoluminescence (PL) spectra show that the 0.1 molar ratio Ag₂O-doped sample had a PL intensity 2.37 times than the undoped sample. This increase is generated by localized surface plasmon resonance coupling between the Ag NPs and CsPbBr₃ QDs. Excessive Ag doping weakens the PL intensity due to spectral self-absorption of the Ag NP surface plasmon resonance (SPR). Self-adsorption of SPR is detrimental to luminescence properties because it increases the amount of photogenerated charge carriers, which proceed through nonradiative relaxation pathways. In addition, stability results of Ag NP-doped-CsPbBr₃ QD glass show that they have excellent stability. This study on Ag NP-doped-CsPbBr₃ QD glass provides a new idea for the future development of perovskite QD optoelectronic devices.