A hunk of pure iron, for example, doesn't tend to stay pure for very long.

例如，一大块纯铁不能长时间保持它的纯度。

They also need purer iron ore, because it does not melt fully in hydrogen-powered furnaces, making it more difficult to skim off contaminants.

他们还需要更纯的铁矿石， 因为它在氢动力熔炉中不会完全熔化，因此更难撇去污染物。

A smelting furnace turned iron ore from the near-by mountain into lumps of pure iron all ready for the farm's blacksmith to hammer and beat into horseshoes, pincers, tongs, crowbars, hammers, and other tools needed on the farm.

一座熔炉把附近山上的铁矿石变成了一块块纯铁，农场里的铁匠可以把它们锤成马蹄铁、钳子、钳子、撬棍、锤子和农场里需要的其他工具。