Development of Lead-Free Copper alloy Manufacturing System Based on Life Cycle Assessment

采用化合物分离法对含铅青铜中铅的脱除方法进行了研究。在熔融的青铜中加入氟化钠，然后加入钙硅化合物。因此，不需要钙与锡的反应，就可以促进钙与铅的反应。采用该方法可以从含Pb质量分数为5.5%的青铜中脱除82%的铅。对原无铅铜合金生产系统和采用生产过程中去除的含铅铜合金废料的新无铅铜合金制造系统进行库存分析。结果表明，从旧的制造系统向新的制造系统的转变显著地减少了全球变暖、酸化、能源消耗和资源消耗等环境影响。因此，从LCA的角度来看，使用回收铜合金废料的新制造系统优于使用原始材料的新制造系统。考察了二硫化钼对青铜加工性能的影响。结果表明，二硫化钼的加入可以显著提高切削力和切屑的可处理性。

The method for removing Pb from bronze containing Pb was examined by the compound-separation method. NaF is added to molten bronze, followed by adding the Ca-Si compound. Therefore, the reaction of ca with Pb is promoted without the reaction of Ca with Sn. Using this method, 82% of Pb can be removed from bronze containing 5.5 mass% Pb.The inventory analysis of both the former Pb-free copper alloy manufacturing system that uses virgin materials and the new one that uses copper alloy scrap containing Pb, which is removed in the production process, was carried out. The results show that the shift from the former manufacturing system to the new one reduces environmental impacts such as global warming, acidification, energy consumption and resource consumption significantly. Thus in the LCA perspective, the new manufacturing system that uses a recycled copper alloy scrap is superior to the former one that uses virgin materials.The effect of molybdenum disulfide on machinability of bronze was examined. The result shows the cutting forces and chip-disposability can be greatly improved by the addition of molybdenum disulfide.