Members of Japan’s Olympic organising committee tabled the idea to government officials and companies earlier this year， local media reports said。
据日本当地媒体报道，日本奥组委成员在今年年初将这一想法提交给了政府官员和一些公司。
Olympic host cities have traditionally obtained the metal from mining firms。
一直以来，奥运主办城市都是从矿业公司处获得制作奖牌的金属。
But Japan， which lacks its own mineral resources， is keen to take the theme of a sustainable future a step further。
但是由于本土缺少矿产资源，日本渴望在“可持续性未来”这个主题上走出更远的一步。
The International Olympic Committee （IOC） has developed strict criteria for the world’s greatest sporting event， and this extends to how the medals should be produced。
国际奥委会（IOC）为这场全世界最盛大的体育赛事制定了严格的标准，包括奥运奖牌应该如何制作。
The Rio Olympics， for example， used gold that was extracted without the use of mercury and a third of the silver and bronze used came from recycled sources。
举例来说，里约奥运会所使用的金在萃取的时候是不能够使用水银的，制作奖牌的银和铜有三分之一来自于可再生资源。
How does e-waste recycling work？
电子垃圾回收工作怎么展开？
Discarded consumer electronics such as smartphones and tablets contain small amounts of precious and rare earth metals， including platinum， palladium， gold， silver， lithium， cobalt and nickel。
废弃的消费电子产品（例如智能手机和平板电脑）含有少量的贵金属和稀土金属，包括铂、钯、金、银、锂、钴、镍。
Scrap cars and home appliances such as fridges and air conditioners also contain these rarer metals， along with base metals， including iron， copper， lead and zinc。
报废的汽车和家用电器（例如冰箱和空调）也含有这些稀有金属，但也含有其他一些基本的金属，包括铁、铜、铅和锌。
Recycling or refining companies either collect or purchase tons of this e-waste and industrial scraps。 They then use chemical processes to separate the various metals。
回收公司和精炼公司都会成吨地收集或购买这些电子垃圾和工业废料。然后就可以用化学反应来分离这些不同的金属。
Much of this work takes place in developing countries such as China， India and Indonesia。
这种工作许多都是在中国、印度和印尼等发展中国家进行的。
Does Japan have enough for 2020？
日本有足够的电子垃圾来制造2020东京奥运会的奖牌吗？
Japan has one of the highest recycling rates in Asia， according to OECD data。 However， this mainly applies to plastic， paper and glass。
据经合组织（OECD）的数据显示，在整个亚洲，日本是回收率最高的几个国家之一。但是日本所回收的物品主要是塑料、纸张和玻璃。
About 650，000 tonnes of small electronics and home appliances are discarded in Japan every year， the Nikkei newspaper said。 However， it is estimated that less than 100，000 tonnes is collected for recycling。
据日本经济新闻报道，日本每年大约要丢弃65万吨小电子产品和家用电器。但是，据估计只有不到10万吨被收集以供回收。
So for the 2020 Games， Japan will probably have to ask individual countries or companies to contribute towards the recycled metal collection effort。
因此，对于2020东京奥运会来说，日本也许将会寻求个别国家或公司的帮助，以协助他们进行回收金属收集工作。
How much metal is needed？
需要多少金属？
The amount of metal needed will depend on the size and number of medals， since each year， they seem to get bigger and heavier。
金属需要的量取决于奥运会奖牌的大小和数量，因为每次奥运会的奖牌都在变大变重。
Five new sports have also been added to the Tokyo 2020 competition， including baseball， karate， skateboarding， sport climbing and surfing。
2020东京奥运会也新增了5个项目，包括棒球、空手道、滑板、攀岩和冲浪。
The 2016 Rio Olympics had the largest medals of any games， weighing in at 500g each and 1cm thick in the middle。
2016里约奥运会的奖牌比以往任何一届奥运会的奖牌都要大，每块奖牌重500克，中央厚度1公分。
The Brazilian Mint produced 5，130 medals in total， up from the 4，700 made by London’s Royal Mint for the 2012 Games。
巴西铸币局为此次奥运会一共制造了5130块奖牌，而伦敦皇家铸币局为2012伦敦奥运会一共制造了4700块奖牌。
