What is the difference betweenferrous sulfate heptahydrate and ferrous sulfate monohydrate? First of all, the two are different in appearance: ferrous sulfate monohydrate, also known as feed grade ferrous sulfate, is produced by wet dissolution and recrystallization, with the appearance of dry white or light white powder solid. Ferrous sulfate heptahydrate is prepared by the reaction of dilute sulfuric acid and iron pin, which is light green or green granular solid. The crystal particles of ferrous sulfate heptahydrate are larger than that of ferrous sulfate monohydrate. Secondly, ferrous sulfate heptahydrate and ferrous sulfate monohydrate have different physical properties: ferrous sulfate monohydrate will decompose into ferric oxide and release sulfur dioxide when heated. Its content is generally over 98%. Its melting point and boiling point are 64℃ and 330℃ respectively. Ferrous sulfate heptahydrate contains seven crystal water, with molecular weight of 278.05, melting point of 69℃ and the content of 80-92%. Compared with ferrous monohydrate, ferrous sulfate heptahydrate is easy to oxidize with air. Finally, the use of ferrous sulfate heptahydrate is different from that of ferrous sulfate monohydrate: ferrous sulfate monohydrate is feed grade, so it is often used as feed additive. It has a very good role in supplying nutritional iron to the livestock, which can prevent the emergence of anemia and enhance the resistance of livestock to diseases in the process of growth. In addition, it can be used as raw material to prepare iron oxide red and other pigments, and gradually applied to the fertilizer market. Ferrous sulfate heptahydrate, as a reducing agent, is widely used in wastewater treatment for decolorization and flocculation. It can also be added to cement to remove toxic chromate.

Ferrous sulfate heptahydrate and ferrous sulfate monohydrate have the same point: because ferrous sulfate monohydrate is prepared by the reprocessing of ferrous sulfate heptahydrate, it contains a large number of ferrous ions. And they all have redox properties, but the oxidation of ferrous sulfate monohydrate after drying is not as strong as that of ferrous sulfate heptahydrate, but ferric sulfate will be formed after oxidation. Its physical properties are insoluble in ethanol. All of them can be used as flower fertilizer, and have a good effect of supplying iron to plants.