So a suitable maturation temperature and sulfuric acid concentration should be chosen for raisingiron recovery.
为了提高铁的提取率,应选择适宜的硫酸浓度和熟化温度。
3
In those stones I saw thundering war drums, fluttering flags, and brave villagers raisingiron halberds against invaders, their blood staining their clothing and seeping into the granite rampart.