Graphite electrodes include:
(1) ordinary power graphite electrode
The graphite electrode with current density lower than 17A/ cm 2 is allowed to be used, which is mainly used in ordinary power electric furnaces such as steel making, silicon smelting and yellow phosphorus smelting.
(2) oxidation resistant coated graphite electrode
Graphite electrode coated with a protective layer of antioxidant (graphite electrode antioxidant). Form both conductive and high temperature oxidation resistant protective layer, reduce the electrode consumption in steelmaking (19%~50%), prolong the service life of the electrode (22%~60%), reduce the electrical energy consumption of the electrode. The spread of this technology can bring about the following economic and social effects:
① The unit consumption of graphite electrode is less, and the production cost has a certain reduction. A certain steel works, for example, not the year production level of LF refining furnace 35 root graphite electrode per week, 165 furnace refining processing consumption calculation, using graphite electrode after oxidation technology, can save 373 a year (153 tons) electrode, a year uhp electrode is 16900 yuan per ton, 2.5857 million yuan can be saved.
② The graphite electrode consumes less power, saves the unit steelmaking electricity consumption, saves the production cost, saves energy!
(3) Due to the less frequency of graphite electrode change, less labor and risk factor of the operator, improve the production efficiency.
(4) Graphite electrode is low consumption and low pollution products, in today's energy conservation, emission reduction and environmental protection advocate, has very important social significance.
This technology is still in the stage of research and development in China, and some domestic manufacturers have begun to produce it. In Japan and other developed countries have been more widely used. At present, there is also a special import of this kind of antioxidant protective coating company.
(3) High power graphite electrode
Graphite electrodes with a current density of 18 to 25A/ cm 2 are allowed, mainly used in high-power electric arc furnaces for steelmaking.
(4) ultra-high power graphite electrode
Graphite electrodes with current densities greater than 25A/ cm 2 are allowed. Mainly used in ultra-high power steel - making arc furnace.
First, what is calcium carbide
Calcium carbide generally refers to calcium carbide, calcium carbide, chemical formula: CaC2, namely calcium carbide, inorganic compounds. White crystal, industrial grayish-black mass with purple or gray cross section. In contact with water, a fierce reaction occurs immediately, forming acetylene and releasing heat. Calcium carbide is an important basic chemical raw material, mainly used to produce acetylene gas. Also used in organic synthesis, oxylene welding and so on.
Second, the purpose
(1) Many organic compounds can be synthesized from acetylene produced by the reaction of calcium carbide with water
For example: synthetic rubber, artificial resin, acetone, enone, carbon black, etc.; At the same time acetylene oxygen flame is widely used in metal welding and cutting.
(2) When heated powdery calcium carbide and nitrogen react to produce calcium cyanide, namely lime nitrogen. The cyanide melt generated by heating lime nitrogen and salt reaction is used in gold mining and non-ferrous metal industry.
(3) calcium carbide itself can be used as a desulfurizer in the iron and steel industry.
(4) production of polyvinyl chloride (PVC), calcium carbide production of PVC using calcium carbide (CaC2), water generated acetylene (C2H2), acetylene and hydrogen chloride (HCl) synthesis of vinyl chloride monomer (CH2CHCl), and then through polymerization reaction to make vinyl chloride into polyvinyl chloride - [CH CHCI] N - chemical reaction method.
(5) the old miners down the mine, the calcium carbide into the iron can weave using the generated acetylene (C2H2) made into calcium carbide lamp.
Three, storage method
Store in a cool, dry and well-ventilated warehouse. Keep away from fire and heat source. Keep relative humidity below 75%. The package must be sealed and protected from moisture. Should be stored separately from acids and alcohols, and do not mix storage. The storage area shall be equipped with suitable materials to hold the leakage. The best way is to put in a high strength moisture-proof box, maintain a stable humidity.
Calcium carbide (CaC₂) also called calcium carbide, natural state for the white crystalline solid, belongs to wet flammable goods, dry non-combustible, and water or moist air contact easy to produce highly flammable acetylene gas (explosion limit of 2.5%-82%< volume percentage >), and acid contact will have a violent reaction, release heat, may cause spashing.
With the coming of flood season and the increase of rainy and wet weather, the production, use and storage enterprises of calcium carbide should strengthen risk control according to the dangerous characteristics of calcium carbide.
First, pay close attention to meteorological forecasts and flood disaster warning information, and implement flood prevention, rain prevention, moisture-proof measures.
Second, calcium carbide storage process should ensure that there is no water or damp, stored in a cool, dry, well-ventilated, do not leak rainwater storeroom, is strictly prohibited after damp packaging storage, storage temperature is controlled below 32℃, relative humidity is kept below 75%, do not mix with acids, halogen (fluorine, chlorine, bromine), alcohol and other mixed storage.
Third, calcium carbide in the process of road transportation should pay attention to the influence of weather, season, temperature and other natural factors, choose the appropriate weather and climate conditions to transport. In case of rain or snow, stop at relevant stations in time, and take safety measures such as preventing moisture.
Fourth, when calcium carbide is on fire in water, dry sand, carbon dioxide or dry powder extinguisher should be used to extinguish the fire. It is forbidden to use water and foam extinguishing agent to extinguish the fire.
Calcium carbide has the following uses:
1, calcium carbide and water reaction to generate acetylene, can be synthesized many organic compounds, such as: synthetic rubber, artificial resin, acetone, enone, carbon black, etc.
2, heating powder calcium carbide and nitrogen, calcium cyanide, namely lime nitrogen; Lime nitrogen is an important raw material for the preparation of cyanuric acid. The melt produced by the reaction of heated lime nitrogen with salt is used in gold mining and non-ferrous metal industry.
3. Calcium carbide itself can be used as a desulfurizer in the iron and steel industry.
4, the production of polyvinyl chloride (PVC) : calcium carbide method production of PVC using calcium carbide (CaC2), water generated acetylene (C2H2), acetylene and hydrogen chloride (HCl) synthesis of vinyl chloride monomer (CH2=CHCl), and then through polymerization reaction to make vinyl chloride into polyvinyl chloride - [CH2 - CHCI] N - chemical reaction method.
5, the old miners under the mine, the calcium carbide into the tin using the generated acetylene (C2H2) made into calcium carbide lamp.
