Storage safety technology of the hottest magnesium

Safety technology for storage of magnesium alloy waste

1. Precautions for magnesium powder Management: the powder produced in grinding is generally recycled with a wet dust collector. The recovered powder is muddy, which contains a small amount of grinding material. In addition, according to different conditions, some powder like chips will also be produced in cutting, which are usually treated as powder. Powder is more dangerous than cutting. Pay special attention to the following aspects: because the powder recovered by wet dust collector contains water, it reacts with water to produce hydrogen in storage. When it does not settle in water, the risk of spontaneous combustion caused by reaction heat is high. It must be the largest non-profit research and development institution in the world to make waste treatment as soon as possible, and it must supplement enough water. Magnesium powder in dry state or containing trace moisture is easy to be ignited and produce violent combustion when encountering open fire. Therefore, care should be taken during storage and disposal, especially to prevent accidents caused by smoking and welding sparks. There should be a special grinding machine for magnesium metal to avoid mixing with aluminum and other metals. The generated powder residues should be cleaned frequently, and the collected powder should be kept in steel containers. Aluminum and other metal powders are as dangerous as magnesium powders. Powder is more dangerous than cutting, so don't keep it. Dispose it as soon as possible. It's safer to dispose magnesium powder by chemical methods

2. Storage of magnesium powder: magnesium powder is more prone to spontaneous combustion than chips, especially wet powder, which is more dangerous, and must not be stored for a long time. It should be treated as industrial waste by chemical treatment as soon as possible. Magnesium powder in dry state should be stored in a steel container with a clean cover. Although it is relatively safe, it is still dangerous. In principle, magnesium powder containing water should not be preserved. When it has to be preserved, you must have a full understanding of the following things. The surface area of powder is larger than that of chip, and it has strong reactivity with moisture. Therefore, the amount of hydrogen and reaction heat is quite large, which is more dangerous. Magnesium powder collected from the wet dust collector shall be discarded immediately after being taken out every day or as frequently as possible. When it is necessary to keep it, the observation time should be shortened as far as possible, and it should be kept under continuous monitoring. Never store magnesium powder in a closed container. In order to facilitate the release of generated hydrogen, small holes should be set on the cover and the container should be placed in a well ventilated place. Pay full attention to open flames and spontaneous combustion during storage. Magnesium in powder piles has a high risk of spontaneous combustion, and should be placed separately from chips and other inflammables

3: storage of chips: because the burning of chips can cause major fire accidents, special attention should be paid to fire prevention in storage. The following items must be strictly observed in storage. The basic consideration is the same as that of powder storage. For chips, the following items should also be paid attention to: Buildings should be of flame-retardant structure and should be completely isolated from combustible materials. Storage site this method stipulates that four types of samples must not leak rain. The cuttings shall be placed in steel or other non combustible containers with clean covers. The storage site of containers shall be selected, and the place where spontaneous combustion will not occur and buildings and other combustible materials shall be considered. The chip oil used in wet processing includes mineral oil insoluble in water and softened oil soluble in water. Both contain water or oil and cannot be mixed with the powder processed and produced in dry state. The chips produced by using water-insoluble chip oil and water-soluble chip oil should not be mixed, but should be put into containers respectively and marked. If hydrogen is produced by chips wetted by water-soluble chip oil and water or oil containing more than 0.2% fatty acids, these water-based chips should be quickly discarded. When it is necessary to store them, vent holes for hydrogen release should be set on the container cover and stored in a well ventilated place. Magnesium chips wetted by passive vegetable oil have the risk of spontaneous combustion, and waste treatment should be done as soon as possible. The above is the precautions in machining. In particular, it should be pointed out that bad habits and carelessness are often the most dangerous inducements to accidents

4: treatment of dissolved slag (sludge, scum):

① dissolved slag will produce a lot of dissolved slag in melting and casting plants. These dissolved slag are mainly produced during refining with dissolving agent, and its specific composition is different from plant to plant. The solvent is generally composed of magnesium chloride, potassium chloride, barium chloride with calcium chloride as the main component, calcium fluoride, magnesium oxide, etc. The so-called sludge is the dissolving slag with the theme of non-metallic substances, oxides, nitrides and aging solvents containing a certain amount of extremely fine metallic magnesium, which are separated and settled during the refining of a group of leading enterprises with independent intellectual property rights and strong core competitiveness by using dissolving agents. Scum refers to the oxide film and nitride formed on the surface of the solution and also attached to the solvent. It contains non-metallic substances, which are lighter than the specific gravity of magnesium, so it floats up. Sludge and scum basically have no value of regeneration and recycling, and are generally treated as waste

China is the country with the fastest development speed and the largest range of rail transit in the world. ② disposal of slag dissolving: sludge and scum contain a large amount of magnesium nitride, particulate magnesium, magnesium chloride and calcium chloride as dissolving agents, which are discarded without treatment. They absorb water and heat, producing hydrogen, biogas, ammonia, etc. Spontaneous combustion will occur under certain conditions, so it must be treated safely as industrial waste. In addition, the sludge condenses to form rock like hard blocks, which are very difficult to break and crush. Water treatment needs to be as fine as possible. Therefore, it is necessary to do as fine treatment as possible when dealing with dissolved slag

③ storage and disposal of dissolved slag: the generated sludge has strong hygroscopicity because it is mainly magnesium chloride and calcium chloride. In addition, the sludge also contains particulate magnesium that reacts with water to produce hydrogen, magnesium nitride that produces ammonia, and magnesium carbide that produces acetylene gas. Therefore, sometimes the above substances absorb moisture and cause gas combustion by reaction heat, resulting in spontaneous combustion. Therefore, in principle, the generated sludge should be treated every day rather than kept. When it is necessary to keep it, even if it is kept for a short time, it should be kept dry, cut off contact with moisture, and placed in a steel container with a cover. For simple burial and waste disposal, there is the possibility of spontaneous combustion based on the above reasons, so it is dangerous