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Kunming, China

Ma L.-W.,Beijing University of Technology | Dong H.-G.,Sino Platinum Metals Co. | Xi X.-L.,Beijing University of Technology | Zhu X.-G.,Beijing University of Technology
Beijing Gongye Daxue Xuebao/Journal of Beijing University of Technology | Year: 2015

The two-step leaching was studied torecover the valuable metals in waste printed circuit boards (PCBs). Firstly, sulfuric acid with hydrogen peroxide was used to leach the base metal; andsecondly, the aqua regiato leach gold in the base metal. The optimal base metal leaching conditions were as follows: hydrogen peroxide of 20 mL; solid-liquid ratio of 1:5; sulfuric acid concentration of 5 mol/L; reaction temperature of 60 ℃ and reaction time of 90 min. Thedissolution ratio of raw material (10 g) reached 90.0% under the above conditions. The gold leaching efficiency reached 97.5% at 40 ℃ with reaction time of 30 min. Studies have shown that the two-step leaching can effectively deal with PCBs, and the gold dissolution process is controlled by diffusion. ©, 2015, Beijing University of Technology. All right reserved. Source


Li Y.,Kunming Institute of Precious Metals | Li Y.,Sino Platinum Metals Co. | Wang J.-k.,Yunnan Metallurgy Group Corporation | Wei C.,Kunming University of Science and Technology | And 3 more authors.
Minerals Engineering | Year: 2010

Low-grade complex Pb-Zn oxide ore is an important source, and the reserve is very great in the world. It is very difficult to obtain Pb and Zn from the source by traditional technology. In this work, a new technology characterized by sulfidation of low grade Pb-Zn oxide ore with elemental sulfur was developed. The effects of temperature, time, particle size and sulfur amount on the sulfidation extent of Pb-Zn oxide ore was studied at a laboratory-scale. The experimental results show that the sulfidation extent of Pb and Zn oxide reaches 98% and 95% under the optimum conditions, respectively. A flotation concentrate was obtained with 38.9% Zn and 10.2% Pb from the materials which was treated by sulfidation, and the recovery of Zn and Pb is 88.2% and 79.5%, respectively. Crown Copyright © 2010. Source


Wang Q.,Kunming Gui Yan Pharmaceutical Co. | Pu S.,Kunming Gui Yan Pharmaceutical Co. | Li Y.,Kunming Gui Yan Pharmaceutical Co. | He J.,Kunming Gui Yan Pharmaceutical Co. | And 4 more authors.
Advanced Materials Research | Year: 2012

In order to obtain a gallic acid platinum complex, the title compound was synthesed from potassium tetrachloroplatinate by the reaction potassium iodide, (1R,2R)-1,2-cyclohexanediamine, silver nitrate and gallic acid respectively. The complex structure and component were characterized by elemental analysis, ESI-MS, 1H-NMR and IR and the anticancer activity was measured by MTT method. The result showed that its structure was consistent with the title compound and had inhibiting effect on the growth of tumor cell lines in vitro. © (2012) Trans Tech Publications, Switzerland. Source


Xing W.,Kunming Institute of Precious Metals | Fan X.,Kunming Institute of Precious Metals | Fan X.,Sino Platinum Metals Co. | Fan X.,Platinum Technology | And 6 more authors.
Xiyou Jinshu/Chinese Journal of Rare Metals | Year: 2014

The kinetics behavior of nickel and cobalt leaching from waste superalloys with sulfuric acid was investigated. The kinetics experiments were carried out with the ratio of liquid to solid of 400:1, the acid concentration of from 10% to 25%(volume fraction) and the temperature of from 55 to 75℃. The results showed that the apparent activation energy of nickel and cobalt was 13.37 and 21.59 kJ·mol-1, respectively. This indicated that the dissolution kinetics followed a shrinking core model with inter-diffusion of nickel, cobalt and sulfate ions through the porous region of alloying layer in the rate determining step. The kinetics study of leaching Ni and Co from waste superalloys with sulfuric acid provided some reference for the recycle of waste superalloy in industry practice. Source


Liu Y.,Sino Platinum Metals Co. | Liu Y.,Kunming Institute of Precious Metals | Jiang G.,Kunming Institute of Precious Metals | Xu K.,Sino Platinum Metals Co. | And 3 more authors.
Jinshu Xuebao/Acta Metallurgica Sinica | Year: 2015

In recent years, there have been great efforts focused on joining ceramics to metals to establish processes for a wide range of industrial uses. Several important problems, however, still remain unsolved. Among them, how to produce atomic bonds at ceramic/metal interfaces and how to minimize the residual stress due to large thermal expansion mismatch between two constituents are the most critical. The thermal expansion mismatch effect is a serious problem because, even if a strong interface could be achieved, joints with large residual stress are easily broken. Therefore, it is desirable to reduce the magnitude of the residual stress. Some researchers have succeeded in achieving a strong joint between alumina and stainless steel by using a soft metallic interlayer. In this study, the effects of interlayers of nickel, copper and copper coated with nickel on the microstructure and shear strength of alumina ceramic and 1Cr18Ni9Ti stainless steel bonding with Ag-Cu-Ti filler metal were investigated. The results indicated that, when using copper as an interlayer, sufficient interfacial reaction between the ceramic and the filler metal could obtain. However, when using nickel as an interlayer, resulting in an insufficient reaction between the ceramic and the filler metal and the formation of large amount Ni3Ti intermetallic compounds, and thus, the strength of the joint decreased heavily. It is very interesting that when using copper coated with Ni, the existence of the small amount of nickel didn't affect the activity of titanium in the filler metal, meanwhile, it decreased the effect of the filler metal on the solubility of copper. Compared with copper and Ni interlayer, this interlayer could reduce interfacial residual stress more effectively. And the shear strength of 109 MPa was obtained when the thickness of Cu was 0.2 mm coated with 30 μm thick nickel. © Copyright. Source

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