Ferrous sulfate, also known as green vitriol, is light green, blue-green or light yellow crystals or particles, odorless and tasteless. Its chemical formula is FeSO4·7H2O, relative molecular mass is 278.02, relative density is 1.898, melting point is 64℃, it loses 6 crystal water at 90℃, and all crystal water at 300℃. It is soluble in water and glycerin, slightly soluble in alcohol, and easily oxidized into yellow or rust color in humid air.
Mechanism of action
Ferrous sulfate can dissociate into Fe2+ and SO42- in aqueous solution. Fe2+ hydrolyzes or reacts with alkali in water to form Fe(OH)2. The flocculation effect of ferrous iron is not as good as ferrous iron. Therefore, when ferrous sulfate is used, methods such as oxidation and aeration are required to oxidize the ferrous iron to ferric iron.
Application of ferrous sulfate
The common ferrous sulfate in the market is usually a by-product of titanium dioxide produced by the decomposition of ilmenite by the sulfuric acid method. It is widely used in printing and dyeing, papermaking, pesticide and sewage treatment industries.
In the sewage treatment process, ferrous sulfate is often used as a flocculant. In various wastewaters, a series of reactions such as electroneutralization, polymerization coagulation, adsorption, bridging, and crosslinking of polluted organic matter or suspended matter in the water make the pollutants form alum precipitation and destroy the chromophoric groups in the wastewater Its decolorization has the functions of coagulation, turbidity removal, decolorization, degreasing and sterilization.
In some cities and industrial wastewater treatment, ferrous sulfate is used as a precipitant to achieve the purpose of removing phosphate. Because of its reducibility, it is also used for the reduction of hexavalent chromium in some electroplating plants.
The printing and dyeing industry can also be used as a precipitant, as a raw material for iron red plants, and also as a dyeing agent, such as: dyeing concrete into rust color, adding ferrous sulfate to iron tannate ink, etc.
In agriculture, it is often used as iron fertilizer and as an iron supplement for plants. It can be used in combination with watering and fertilization to promote the formation of chlorophyll, prevent yellowing disease caused by iron deficiency in plants, and improve the utilization of soil nutrients. Enhance soil moisture retention capacity; also can be used as pesticides and herbicides to treat wheat smut and fruit tree disease; in agriculture, it is mixed with soil to adjust soil acidity and alkalinity and improve soil compaction. , Prevent the invasion of plant soil-borne diseases, remove moss and lichen.
Medically, it can be used as an iron supplement to treat iron deficiency anemia.
In the food industry, it can also be used as an antioxidant for anti-corrosion preservation in food packaging.
Changlong Technology adopts a new process independently developed to produce dried ferrous sulfate, that is, ferrous sulfate pentahydrate, which solves the "pouring soup" phenomenon of ferrous sulfate produced by traditional processes (the surface of the dried ferrous sulfate is dry Yes, but the inside of the crystal is wet), the content of dried ferrous sulfate produced is stable above 98% (calculated based on ferrous sulfate heptahydrate), and the content of dried ferrous sulfate produced by traditional technology is basically 93%-100% .
The quality is stable, not easy to compact, and basically does not absorb moisture.
The content exceeds 98%;
Good decolorization effect. It has obvious effect on wastewater treatment such as printing and dyeing and washing;
The price is low, it can be added directly, it is convenient to use, and the cost is lower than other chemicals when treating the same sewage.
When ferrous sulfate is used as a water purifier, it is usually prepared as a 5%-10% aqueous solution and then added to the raw water. After adjusting the pH of the raw water to 9-11 with lime, the use effect is more significant.