氢氧化亚铁和氢氧化铁的制取课题：氢氧化亚铁和氢氧化铁的制取摘要：氢氧化亚铁与氢氧化铁都是重要的无机化合物，本文介绍了两者的主要性质，并讨论了它们的制取方法。
以铁和氢氧化钠为原料，采用催化反应的方法，可在一定的pH值和温度条件下，形成氢氧化铁以及相应的氢氧化亚铁。
另外，采用碱溶解法、湿法法等，也可以制取氢氧化铁和氢氧化亚铁。
本文还介绍了高化氢氧化铁、氢氧化铁凝胶等制备过程。
关键词：氢氧化亚铁，氢氧化铁，催化，碱溶解，高化IntroductionHydrated ferric oxide and ferrous hydroxide are important inorganic compounds. They have a variety of physical and chemical properties, and have a wide range of applications in chemical production and life. This paper introduces the main properties of the two, and discusses their preparation methods, so as to provide references for the production of ferric hydroxide and hydrous ferric oxide.1 Properties of Hydrated Ferric Oxide and FerrousHydroxideHydrated ferric oxide, chemical formula is Fe(OH)3, is an amorphous white-gray powder. The structure is three-dimensional, the crystals are in a rhombic crystal system,and its Mohs hardness is up to 4-4.5. Under normaltemperature and pressure, it has a melting point of 630-650 °C, a boiling point of 7000-9000 °C and specificgravity of 5.28-5.32 g/cm3. Soluble in acids and ammonium salts, insoluble in water, almost insoluble in ethanol,alkali and other organic solvents. The lattice constants area = 5.35 Å and c = 6.41 Å.Ferrous hydroxide, chemical formula Fe(OH)2, is an amorphous light grey powder. Its structure is three-dimensional and of rhombic crystal system. Under normal temperature and pressure, it has melting point at 667℃,boiling point of 6500-7000℃ and specific gravity of 4.19g/cm3. It is soluble in acids and alkalis, almost insolublein water, ethanol, and other organic solvents. The lattice constants are a = 4.9680 Å and c = 4.7144 Å.2 Method of Preparing Hydrous Ferric Oxide and Ferrous Hydroxide2.1 Catalytic Reaction MethodThe catalytic reaction method is to use iron and sodium hydroxide as raw materials, under the condition of thecertain pH value and temperature, the reaction of ferrous hydroxide and sodium hydroxide is carried out, and the products of ferrous hydroxide and hydrous ferric oxide are formed. First, the iron and sodium hydroxide are weighed according to the molar ratio of 1:3, and then the solution is stirred evenly and heated to 100℃. Under the basic condition, the reaction progresses rapidly, and the reaction reaches the end after 1.5h. Finally, the products are cooled, filteredand washed with deionized water, and then dried to obtain the products.2.2 Alkali Dissolution MethodAlkali dissolution method is to use a large amount of strong alkali, such as caustic soda and caustic potash, as the dissolution agent to obtain the correspondingproducts.The method is as follows: about 20 g of iron oxideis divided into two parts, one of which is added to the aqueous solution of caustic soda at a concentration of 26.9%, and the other is added to the aqueous solution of caustic potash at a concentration of 35.3%. After three hours of stirring at about 60℃, the reaction is over. Then use filter paper to filter out insoluble substances, and wash with deionized water repeatedly to obtain the product. After drying, the products are hydrous ferric oxide and ferrous hydroxide.2.3 Wet ProcessUsing FeCl2, FeCl3 and NaOH as raw materials, FeOH2 andFe(OH)3 can be obtained by wet process. The reacting system needs to be controlled at the alkaline side. The molar ratio of Fe2+ and Fe3+ is 1:1, and the molar ratio of Fe3+ and NaOH is 1:3. The production method is as follows: firstly, prepare the FeCl2 and FeCl3 aqueous solution in the beaker according to certain concentration. Then slowly add a certain concentration of NaOH aqueous solution to the FeCl2, FeCl3 aqueous solution, and use the magnetic stirrer to make the FeCl2 and FeCl3 aqueous solution evenly dispersed in the NaOH aqueous solution. After stirring for 1 hour at the same temperature, the reaction is over and the products formed are hydrous ferric oxide and ferrous hydroxide. After cooling andfiltration, the product of the reaction is obtained bywashing with deionized water and drying.2.4 Preparation of High-Metallized Ferric HydroxideHigh-metallized ferric hydroxide has higher Ferric hydroxide content and better stability. Its preparationmethod is as follows: firstly, prepare the FeCl2, FeCl3 aqueous solution and the NaOH aqueous solution with certain concentration. Then, slowly add NaOH aqueous solution toFeCl2, FeCl3 aqueous solution, add FeCl2, FeCl3 aqueous solution and NaOH aqueous solution in the ratio of 1:3:3, and add the average particle diameter 0.3-3μm ferric hydroxide into the mixture solution. After stirring, the molar ratio of Fe2+ with NAOH should be controlled to be 1:[2~2.5], and the reaction time should be 1-2h. After the reaction is completed, it can be obtained after cooling, filtering and washing with deionized water.2.5 Preparation of Ferric Hydroxide GelThe preparation of ferric hydroxide gel includes two steps. The first step is the preparation of ferric hydroxide. Please refer to the catalytic reaction method in the above paragraph 2.1 for details. The second step is to add the ferric hydroxide solution obtained in the first step into a neutral gelator solution, and evenly mix them, and stir for 30 minutes. Then, the obtained gel is washed with deionizedwater several times and dried for a certain time to obtainthe finished product. Experiments have shown that thegelation rate of ferric hydroxide was up to 70%.ConclusionThat's all for this article. In summary, hydrated ferric oxide and ferrous hydroxide have many important physical and chemical properties, and they have high application value in chemical production and life. This paper mainly introducesthe properties of hydrated ferric oxide and ferrous hydroxide, and discusses their preparation methods. By catalytic reaction, alkali dissolution, wet process and other methods, hydrous ferric oxide and ferrous hydroxide can be prepared.In addition, this paper also introduces the preparation process of high-metallized ferric hydroxide and ferric hydroxide gel, so as to provide references for thepreparation of the two products.。
