In this paper, the recovery and nanoparticle synthesis of Ag from low temperature co-fired ceramic (LTCC) by-products are studied. The effect of reaction behavior on Ag leaching conditions from the LTCC by-products is confirmed. The optimum leaching conditions are determined to be: 5 M HNO₃, a reaction temperature of 75°C, and a pulp density of 50 g/L at 60 min. For the selective recovery of Ag, the [Cl]/[Ag] equivalence ratio experiment is performed using added HCl; most of the Ag (more than 99%) is recovered. The XRD and MP-AES results confirm that the powder is AgCl and that impurities are at less than 1%. Ag nanoparticles are synthesized using a chemical reduction process for recycling, NaBH4 and PVP are used as reducing agents and dispersion stabilizers. UV-vis and FE-SEM results show that AgCl powder is precipitated and that Ag nanoparticles are synthesized. Ag nanoparticles of 100% Ag are obtained under the chemical reaction conditions.

There has been much interest in recycling electronic wastes in order to mitigate environmental problems and to recover the large amount of constituent metals. Silver recovery from electronic waste is extensively studied because of environmental and economic benefits and the use of silver in fabricating nanodevices. Hydrometallurgical processing is often used for silver recovery because it has the advantages of low cost and ease of control. Research on synthesis recovered silver into nanoparticles is needed for application to transistors and solar cells. In this study, silver is selectively recovered from the by-product of electrodes. Silver precursors are prepared using the dissolution characteristics of the leaching solution. In the liquid reduction process, silver nanoparticles are synthesized under various surfactant conditions and then analyzed. The purity of the recovered silver is 99.24%, and the average particle size of the silver nanoparticles is 68 nm.

Ag nanoparticles are extensively studied and utilized due to their excellent catalysis, antibiosis and optical properties. They can be easily synthesized by chemical reduction methods and it is possible to prepare particles of uniform size and high purity. These methods are divided into vapor methods and liquid phase reduction methods. In the present study, Ag particles are prepared and analyzed through two chemical reduction methods using solvents containing a silver nitrate precursor. When Ag ions are reduced using a reductant in the aqueous solution, it is possible to control the Ag particle size by controlling the formic acid ratio. In addition, in the Polyol process, Ag nanoparticles prepared at various temperatures and reaction time conditions have multiple twinned and anisotropic structures, and the particle size variation can be confirmed using field emissions scanning electron microscopy and by analyzing the UV-vis spectrum.

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• Recovery and Synthesis of Silver Nanoparticles from Leaching Solution of LTCC Electrode By-Products
  Juyeon Yoo, Yubin Kang, Jinju Park, Hojin Ryu, Jin-Ho Yoon, Kun-Jae Lee
  Journal of Korean Powder Metallurgy Institute.2017; 24(4): 315.     CrossRef

Copper nanoparticles attract much attention as substitutes of noble metals such as silver and can help reduce the manufacturing cost of electronic products due to their lower cost and good conductivity. In the present work, the chemical reduction is examined to optimize the synthesis of nano-sized copper particles from copper sulfate. Sodium borohydride and ascorbic acid are used as reducing and antioxidant agents, respectively. Polyethylene glycol (PEG) is used as a size-control and capping agent. An appropriate dose of PEG inhibits the abnormal growth of copper nanoparticles, maintaining chemical stability. The addition of ascorbic acid prevents the oxidation of nanoparticles during synthesis and storage. Transmission electron microscopy (TEM) and Fourier transform infrared spectroscopy (FTIR) are used to investigate the size of the synthesized nanoparticles and the coordination between copper nanoparticles and PEG. For chemical reduction, copper nanoparticles less than 100 nm in size without oxidized layers are successfully obtained by the present method.

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• Correlation between electrical conductivity and antibacterial activity of chitosan-stabilized copper and silver nanoparticles
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• Green Synthesis and Characterization of Natural Magnetic Particles/Chitosan Composite Material Impregnated with Copper Nanoparticles
  Defia Indah Permatasari, Bambang Rusdiarso, Nuryono Nuryono
  Solid State Phenomena.2022; 339: 19.     CrossRef
• Copper Nanoparticle(CuNP’s)Synthesis: A review of the various ways with Photocatalytic and Antibacterial Activity
  Israfil Alam Tito, Sahab Uddin, Shafiul Islam, Snahasish Bhowmik
  Oriental Journal Of Chemistry.2021; 37(5): 1030.     CrossRef

Cobalt coated tungsten carbide-cobalt composite powder has been prepared through wet chemical reduction method. The cobalt sulfate solution was converted to the cobalt chloride then the cobalt hydroxide. The tungsten carbide powders were added in to the cobalt hydroxide, the cobalt hydroxide was reduced and coated over tungsten carbide powder using hypo-phosphorous acid. Both the cobalt and the tungsten carbide phase peaks were evident in the tungsten carbide-cobalt composite powder by X-ray diffraction. The average particle size measured via scanning electron microscope, particle size analysis was around 380 nm and the thickness of coated cobalt was determined to be 30~40 nm by transmission electron microscopy.

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• Electroless Ni-P deposition on WC powders through direct PdCl2 activation and study on the underlying mechanisms
  Peng Tang, Shuwen Jiang, Jiawei Yan, Xianquan Li
  Next Materials.2025; 6: 100496.     CrossRef
• Pre-treatments of initial materials for controlling synthesized TaC characteristics in the SHS process
  Jae Jin Sim, Sang Hoon Choi, Ji Hwan Park, Il Kyu Park, Jae Hong Lim, Kyoung Tae Park
  journal of Korean Powder Metallurgy Institute.2018; 25(3): 251.     CrossRef
• Spark plasma sintering of WC–Co tool materials prepared with emphasis on WC core–Co shell structure development
  Sungkyu Lee, Hyun Seon Hong, Hyo-Seob Kim, Soon-Jik Hong, Jin-Ho Yoon
  International Journal of Refractory Metals and Hard Materials.2015; 53: 41.     CrossRef