various magnesium oxide and magnesium hydroxide.

magnesium oxide Magnesium oxide has been widely used in various fields after continuous development in recent years. Magnesium oxide is a white powder, which exists in the form of free magnesite in nature. The main component of magnesite is magnesium carbonate, and the main component of dolomite is the eutectic of MgCO3 and CaCO3. Artificial marble has a specific gravity of 3.65-3.9, a melting point of 2800℃ and a relative molecular weight of 40.3. Magnesium oxide can be roughly divided into the following categories according to different production processes and uses: calcined magnesia According to the operating temperature, the magnesium oxide produced by calcining magnesite at high temperature is calcined magnesium oxide; Magnesium oxide burned by coke at 1400-1800℃ is reburning magnesium, also called dead burning magnesium. Or coal gas as fuel at 700-1000℃ is light burnt powder, also called caustic magnesium. Low-grade magnesia, also called magnesia powder, is fired by mixing low-grade magnesite and anthracite. The chemical composition of magnesite is MgCO3, the relative molecular weight is 84.31, MgCO3 is the main component, SiO2, CaO, Al2O3 and Fe2O3 are the secondary components, and the content of MgO is usually 35%-47%. The reburning magnesite is mainly used for refractory materials, and is also used in the fields of manufacturing magnesia-chrome bricks and calcium-magnesia-carbon bricks, insulating fillers for electric heating and electrical components, feed, building materials, etc. Industrial magnesium oxide Industrial magnesium oxide is also called light magnesium oxide, and its bulk density is between 0.2-0.3g/ml. Magnesium oxide prepared from MgCl·6H2O or sea brine is light magnesium oxide, and magnesium oxide produced by dolomite carbonization is also classified as light magnesium oxide. Light magnesium oxide is odorless, tasteless and nontoxic white amorphous powder, which is mainly used to manufacture enamel, ceramics and refractory materials. Acting as filler in the production of polishing adhesive and paint; Acting as accelerant and catalyst in artificial fiber and rubber (fluororubber and neoprene); In food processing, it can be used as decolorant and ice cream powder PH regulator in refined granulated sugar. It is used as laxative and antacid in medicine for treating duodenal ulcer and hyperacidity. As animal feed and fertilizer in agriculture; In the construction industry, it can produce special cement and insulation board containing magnesium. In addition, it can also be used for water treatment and flue gas flue washing, and has applications in cable, glass dye, uranium processing, silicon steel industry, insulating material industry, petroleum additive, electronic industry, foundry, phenolic plastics and other industries. magnesiumoxide,heavy The bulk density of heavy magnesium oxide obtained by deep processing of light burned magnesium oxide and separation of impurities is between 0.5 and 0.7g/ml. Heavy magnesium oxide can replace light magnesium oxide in magnetic materials for color TV deflection coils (soft magnetic ferrite) and other ferromagnetic materials. Acting as polishing agent in steel ball polishing industry; Dyes are used as auxiliary materials in the production of aminophenol. Electrical appliances are used as raw materials of phenolic resin. Secondly, it is also used in ceramic glass, industrial catalyst, feed and environmental protection industries. active magnesium oxide Active magnesium oxide is one of many varieties of magnesium oxide products. Activity refers to the reaction difficulty of magnesium oxide, which is determined by the thickness of magnesium oxide solid particles (specific surface area). Some indexes of active magnesium oxide are different from those of ordinary magnesium oxide, such as proper particle size distribution, average particle size < 2μm (2000nm); The microscopic morphology is irregular particles or nearly spherical particles or flaky crystals, and the activity marked by citric acid (CAA value) is 12.25s (the smaller the value, the higher the activity). The activity expressed by iodine uptake value was 80~120 (mgI2/ 100gMgO). The specific surface area is between 5 and 20 m2/g, and the apparent specific volume is between 6 8.5 ml/g. It can be said that heavy magnesium oxide is pure Mg0, and light magnesium oxide is xMg0*YMg(0H)2, that is, basic magnesium oxide, and the percentage of light magnesium oxide plays an important role in the activity. Generally, high-activity magnesium oxide is prepared by long time warp of basic magnesium carbonate at low temperature. The furnace structure is special, the energy consumption is high, and the apparent specific volume of the prepared product is large. magnesium hydrate Magnesium hydroxide is an inorganic weak base product, which is called "green neutralizer", "environment friendly flame retardant" and "the third alkali" because of its strong buffer performance, high activity and adsorption capacity, non-corrosive, non-toxic and harmless, etc. It is one of the products that are favored and respected in the process of promoting sustainable development strategy, protecting the environment and benefiting ecological development. Magnesium hydroxide can also be used as an intermediate material to produce magnesium oxide. Ultra-fine magnesium hydroxide is also one of the important raw materials for producing nano magnesium oxide. As a product, it has many uses, among which large consumption and remarkable use effect are mainly in two major fields. First, as an inorganic additive non-toxic flame retardant, it has various properties such as flame retardancy, smoke elimination, drip resistance and filling; The second is the application in the field of environmental protection. As an environmental protection product, because of its excellent performance, it has occupied the first place in the consumption of magnesium hydroxide. The preparation method of magnesium hydroxide includes: 1. Physical crushing method Physical crushing method refers to the direct crushing of ore, and the coarse grinding by dry method and ultra-fine grinding by wet method, so as to produce magnesium hydroxide products with the required granularity grade, and the commonly used ore is brucite. 2. Calcination and hydration method of ore This method calcines the ore and hydrates the prepared magnesium oxide to prepare magnesium hydroxide, which is the process of magnesium oxide dissolution and magnesium hydroxide precipitation, and the dissolution of magnesium oxide is the control step. Because of the different ore composition, magnesite is used more. 3. Liquid-phase precipitation There are two sources of raw materials in this method. One is that magnesite, dolomite, serpentine, etc. are treated by acid hydrolysis or other methods to obtain magnesium salt, which is precipitated with alkali to prepare magnesium hydroxide. One is that magnesium salt obtained from seawater, salt lake water and well brine is precipitated with alkali to prepare magnesium hydroxide.