ferrum pulveratum

例句：

1. 1. The ancient city iscovered with layers of ferrum pulveratum from the past centuries.
   这座古城被过去几个世纪的铁粉覆盖。
2. 2. Thescientist used a special machine to grind upthe ferrum pulveratum foranalysis.
   科学家使用一种特殊机器将铁粉磨碎以便分析。
3. 3. Theold books were filled withnotes and diagrams made withferrum pulveratum.
   旧书里充满了用铁粉制成的笔记和图表。