Ferrous Sulphate Heptahydrate

he ferrous ion (Fe²⁺) in ferrous sulfate heptahydrate (FeSO₄·7H₂O) is reducing, while heavy metal chromium usually exists in the form of high-valent chromate in the cement production process and is oxidizing. Ferrous ions can reduce high-valent chromium to low-valent chromium, such as reducing hexavalent chromium (Cr(VI)) to trivalent chromium (Cr(III)). The trivalent chromium hydroxide has a low solubility and is easy to form a precipitate under alkaline conditions, so it can be separated from cement raw materials or products by filtration and other methods to achieve the purpose of removing heavy metal chromium.