Triiron Tetraoxide Has Excellent Electrical Conductivity
Ferrosoferric oxide is the only iron compound that can be magnetized in the secondary school. Ferroferric oxide contained Fe2 + and Fe3 +, and X-ray diffraction experiments showed that the ferroferric oxide has a trans-spinel structure, and the ferrate ion FeO₂²²- never existed in the crystal. Ferrosoferric oxide, also known as magnetic iron oxide, iron oxide black, magnets, magnets, magnetite, natural mineral type magnetite. Iron in ferroferric oxide in two valences for the trans-spinel structure, that is, [Fe Ⅲ] t [Fe Ⅲ Fe Ⅱ] o O ₄, the most cubic oxygen cubic accumulation. In addition, ferroferric oxide is also a conductor because in magnetite, Fe 2+ and Fe 3+ are arranged in an octahedral arrangement in an almost random order and the electrons can rapidly shift between the two oxidation states of iron, Therefore, ferroferric oxide solid has excellent electrical conductivity.
Ferric oxide, chemical formula Fe 3O 4. Commonly known as iron oxide black, magnet, magnetite, black iron, with black magnetic crystals, it is also known as magnetic iron oxide. Can not be read as "ferrous ferrite" or "ferrous iron [Fe (FeO 2) 2]" and is not a mixture of ferric oxide and ferrous oxide but can be approximated as ferrous oxide and ferric oxide compound of. This material is soluble in acid solution, insoluble in water, alkali solution and organic solvents such as ethanol and ether. Natural ferrosoferric oxide is insoluble in acid solution and easily oxidized into iron oxide (Fe2O3) in the air under humid conditions. They are commonly used as pigments and polishes, as well as tapes and telecommunications equipment.
Hydrogen reduction of α-Fe2O3
The high purity powdery α-Fe2O3 into the plate, the powder layer should not be too thick. After the tray into the reaction tube, the introduction of high purity nitrogen to replace the air completely out. Then slowly through the scrubber bottle into the water-saturated hydrogen. Heating temperature 300 ~ 400 ℃ (for example 330 ℃) is more appropriate. Make sure the reaction is complete (usually 1 ~ 3h) after cooling, stop sending hydrogen, and then replaced with nitrogen, remove the sample. The amount of water vapor is insufficient, the heating temperature is too high or too much reduction will generate FeO, it must be noted. Increase the gas bottle temperature can increase the amount of water vapor (40 ~ 60 ℃ more appropriate). The acicular α-FeO (OH) as the starting material was dehydrated to obtain α-Fe2O3. With this α-Fe2O3 needle acicular ferroferric oxide particles can be obtained. Black tape is the use of such ferrosilicon as a tape recording medium.
Ferrous sulfate and ferrous sulfate are reacted to obtain ferrous sulfate, then adding caustic soda and ferric oxide to carry out an adduct reaction at 95 to 105 DEG C to generate ferriferrous oxide, filtering, drying and crushing to obtain ferric oxide black.
Slow oxidation of ferrous hydroxide
A ferroferric oxide precipitate containing aqueous solution is heated to a temperature of 70 ° C or higher and slowly oxidized to obtain ferroferric oxide powder consisting of relatively uniform regular octahedron or cubic single crystal particles having an edge length of about 0.2 μm. Air bubbles can also be transported as a means of oxidation. Oxidants like KNO3 can also be used.
The skilled operator can get the stoichiometric composition of Fe3.00O4.00 of the ferroferric oxide, Harber method 220g of 20% ammonia solution is added to 2.2L FeSO4 · 7H2O aqueous solution, boil under air cut off (can be equipped with capillary Round bottom flask) and a boiled concentrated solution of 25.5 g KNO3 was added.
Add alkali method
Ferrous sulfate solution plus alkali oxidation or iron salt and ferrous salt solution by a certain percentage of mixed alkali precipitation after the system.