Leaching of arsenic from arsenic and iron slag obtained from cobalt metallurgy with sodium hydroxide has been studied. 研究了用氢氧化钠浸出钴冶金过程中产出的高砷铁渣中的砷。
The best presidents are like magnets below a piece of paper, invisibly aligning iron filings into a new pattern of their making. 最好的总统，就像放在纸下面的一块磁铁，虽然看不见，但会吸引铁渣形成新的图案。
