西安南郊出土一枚拜占廷金币的科学分析与制作工艺研究

陕西省考古研究院文物保护研究室在对该院历年发掘出土的古代金银币进行保护处理时,发现了一枚特殊的拜占廷金币。该金币与其它金币从外观颜色以及表面成分上均有区别。为了了解该金币的制作工艺,本文利用扫描电子显微镜及能谱分析仪,对该金币与一枚拜占廷纯金币和一枚汉代鎏金铜币分别从表面微观形貌和成分分析两方面进行了对比研究。根据分析及对比结果,初步认定该金币很可能是以金汞剂(金泥)为原材料,采用模制法制作金币粗胎,再加热使汞挥发而制成的。

Wheat flour-derived N-doped mesoporous carbon extrudes as an efficient support for Au catalyst in acetylene hydrochlorination

We recently reported an N‐doped mesoporous carbon(N‐MC)extrudate,with major quaternary N species,prepared by a cheap and convenient method through direct carbonization of wheat flour with silica,which has excellent catalytic performance in acetylene hydrochlorination.Herein,we examined the activity of Au supported on N‐MC(Au/N‐MC)and compared it with that of Au supported on nitrogen‐free mesoporous carbon(Au/MC).The acetylene conversion of Au/N‐MC was 50%at 180°C with an acetylene space velocity of 600 h–1 and VHCl/VC2H2 of 1.1,which was double the activity of Au/MC(25%).The introduced nitrogen atoms acted as anchor sites that stabilized the Au3+species and inhibited the reduction of Au3+to Au0 during the preparation of Au/N‐MC catalysts.

Co-intensification of cyanide leaching gold by mercury ions and oxidant

The effects of mercury ions on gold cyanidation were studied. The results show that under low cyanide concentration, gold cyanide process is controlled by CN- transfer, while at higher cyanide concentration, there forms passivation on gold surface. Therefore, chemical oxidation of gold in cyanide solution of higher concentration is controlled by surface reaction. Small quantity of additions of mercury ions bring about great increases in anodic gold dissolution rate, decreases the passivation and reduces the equilibrium activated energy. In addition, they also markedly change the effect pattern of cyanide concentration. Mercury ions show positive effects on cathodic reduction of oxygen and raise the rate of electrochemical step of the cathodic reduction of oxygen. Addition of a certain amount of hydrogen peroxide is confirmed to be an effective way for intensification of cathodic process on gold electrode. Active potential range and current peak on anodic dissolution are enlarged when being co-intensified with Hg^2＋ and hydrogen peroxide. Co-intensifying effect may be obtained and gold from gold concentrates. gold leaching rate is considerably increased on cyanide leaching of

非物质文化遗产传统技艺——传统鎏金技艺

鎏金工艺是我国的一种传统的技艺,青铜鎏金的技术发明始于战国,至今已有两千多年的历史了,传统鎏金技艺操作步骤就是先把金和水银高温合成金汞剂(金泥),把它涂在青铜器或银器的表面上,加热水银蒸发金就会牢牢地附在铜器表面不脱落,经过两三次操作后,就形成了金光闪闪的鎏金器物。