Research On Smelting Technology Of Several Lead And Silver Sites In Yunnan

Most of the research on the lead and silver metallurgical techniques in the acade mic circle focuses on the interpretation of ancient documents,and there is little study on the analysis of slags collected from the lead and silver sites.Up to now,no schol ars have discussed the metallurgical relics of lead and silver sites in Yunnan.Therefor e,this study plays a positive role in revealing the lead and silver metallurgical techni ques in Yunnan.Guanyinshan site,Luoze community site,Caojiaping site and Houzhai village site are respectively located in Luozeshe town and Longjie township in Yiliang County.Fu jiashaopo site is located in Laodian Town,Qiaojia County.Baixiang factory is located in Binchuan County.Shiyang factory is located in Shuangbai County.Laochang village is located in Nanhua County.The period of eight lead and silver metallurgical sites is the Qing Dynasty,with a large number of slag distributed in the sites.The methods such as literature survey,field investigation and experiment analysis were applied to this research.The slags discovered at the eight sites were mainly exa mined and analyzed by scanning electron microscope(SEM),which preliminarily reveale d the silver and lead smelting technology of these eight sites.The result was obtained that the sites of Guanyinshan,Caojiaping,Luozeshe in Yiliang County and Baixiang f actory site used lead smelting furnace,added charcoal and calcium fluxs,and employe d roasting-reduction smelting method to smelt lead-zinc ores containing silver.The sm elting products were considered as lead bullion containing silver and slags.The sites of Fujiashaopo,Houzhai village,Shiyang factory and Laochang village utilized cupellat ion furnace.The lead bullion containing silver was oxidized and blown with charcoal as fuel.The smelting product was considered to be pure silver and lead oxide slags.T he silicic acidity,alkalinity and density of slags basically meet the requirements of mo dern metallurgical theory for the physical and chemical properties of slags.According to the research on literature survey and field investigation,it was found that the size of lead smelting furnace was gradually expanded,the furnace type was constantly cha nging,and the efficiency was also correspondingly developed while reducing the labor force;the structure of cupellation furnace was consistent,all of which were elliptical,and the effective separation of fuel and lead pool in the furnace was realized through sand bars,different hoods were used for different types of minerals.Based on the fiel d investigation of two lead and silver sites in Shuangbai County,it was shown that there were two types of lead smelting furnaces: semi-circular and square.It was specula ted that two different lead smelting technologies were used in the two places.In view of the modern metallurgical theory,it could be concluded that the sintering-reduction smelting method was mainly used to smelt lead-zinc ores containing silver in the old Shiyang factory site,while the roasting-reduction method was mainly adopted in the n ew Shiyang factory site.Due to the limited materials and the problem of ventilation not recorded in the literature,the specific silver extraction methods of the eight sites need to be further st udied and discussed in detail through archaeological discovery.