Recycling it requires only a tiny fraction of the energy consumed when mining bauxite and refining it into the same amount ofmetal.
回收它们所需要消耗的能量，跟重新开掘并提炼相同质量金属的能耗相比，只是一个很小的数目而已。
2
They tried to hasten this transformation by heating and refining the metal in a variety of chemical processes, most of which were kept secret.
他们尝试用各种化学方法加热、冶炼金属来加速这种转化，但大部分方法是秘密进行的。
3
Metal thread feeding machine is one of the refining equipment outside the steel-making furnace, which is quite important to improve steel-making quality.