Modern writing inks usually contain ferrous sulfate with a small amount of an acid; on paper they darken and bond becoming permanent.

现代写字用的墨水通常包括了硫酸亚铁和少量的酸；写在纸上，颜色会越来越深，且能保持永不褪色。

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The ferrous oxalate with crystal water was prepared with ferrous ammonium sulfate and oxalic acid in acid medium.

采用硫酸亚铁铵和草酸溶液在酸性介质条件下合成含有结晶水的草酸亚铁。

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A new process that industrial nitric acid reacts with iron chippings and shavings to produce ferrous nitrate solution is presented.

本文介绍了采用工业硝酸酸化废旧铁屑、制取硝酸亚铁溶液，并以该溶液为主要原料研制新型铁-铬系中温变换催化剂。

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