February 3, 2023
Ferrous sulfate is blue-green monoclinic crystal or particle, odorless. It is weathered in dry air and oxidized to brown basic ferric sulfate in wet air. It becomes tetrahydrate at 56.6 ° C and monohydrate at 65 ° C. Soluble in water, almost insoluble in ethanol. Its aqueous solution oxidizes slowly in the air when it is cold, and oxidizes quickly when it is hot. Adding alkali or dew can accelerate its oxidation. Relative density (d15) 1.897. It is irritating. Anhydrous ferrous sulfate is a white powder, and the crystal containing crystalline water is light green crystal, commonly known as "green alum", which is light green when dissolved in aqueous solution.
Ferrous sulfate can be used for the determination of platinum, selenium, nitrite and nitrate by chromatography reagent and drop analysis. Ferrous sulfate can also be used as reducing agent, manufacturing ferrite, water purification, polymerization catalyst, photographic plate making, etc.
Chemical properties of ferrous sulfate
Ferrous sulfate is reductive. It is decomposed by high heat to release toxic gas. In the laboratory, it can be obtained by reacting copper sulfate solution with iron. It will be weathered in dry air. It is easy to oxidize into brown basic ferric sulfate which is insoluble in water in moist air. 10% aqueous solution is acidic to litmus (Ph value is about 3.7). When heated to 70~73% C, 3 molecules of water will be lost, when heated to 80~123 * C, 6 molecules of water will be lost, and when heated to above 156 ° C, it will be converted into basic ferric sulfate.
Function and use of ferrous sulfate
Ferrous sulfate can be used to make iron salts, iron oxide pigments, mordants, water purification agents, preservatives, disinfectants, etc.
1. Water treatment: ferrous sulfate is used for flocculation and purification of water and removal of phosphate from urban and industrial sewage to prevent eutrophication of water.
2. Reducing agent: a large amount of ferrous sulfate is used as reducing agent, mainly reducing chromate in cement.
3. Medicinal: ferrous sulfate is used to treat iron deficiency anemia; It is also used to add iron to foods. Long-term overdose may cause side effects such as abdominal pain and nausea. In medicine, it can also be used as a local astringent and blood tonic, and can be used for chronic blood loss caused by uterine leiomyoma arch.
A. Ferrous sulfate is required for the production of iron tannate ink and other inks. The mordant for wood dyeing also contains ferrous sulfate.
B. Ferrous sulfate can be used to dye the concrete yellow rust color.
C. The maple wood is dyed with silver color with ferrous sulfate for carpentry.
5. Agriculture: regulate the soil acidity and alkalinity, promote the formation of chlorophyll (also known as iron fertilizer), and prevent and cure the yellowing disease of flowers and trees caused by iron deficiency. It is an indispensable element of acid-loving flowers and trees, especially iron trees. In agriculture, it can also be used as a pesticide to prevent and control wheat smut, apple and pear scab, and fruit tree rot; It can also be used as fertilizer to remove moss and lichen from tree trunks.
6. Analytical chemistry: ferrous sulfate can be used as a chromatographic analysis reagent.