rp 400 graphite electrode

Determination of the largest particle size in the formula of rp 400 graphite electrode

Kneading: At a certain temperature, the process of kneading various quantitative carbon particles and powder materials with quantitative binders is called kneading. Kneading process: dry mixing (20-35 minutes) wet mixing (40-55 minutes) kneading effect:

① During dry mixing, all kinds of raw materials are evenly mixed, and solid carbon materials of different particle diameters are mixed and filled evenly, which improves the density of the mixture;

② After coal tar pitch is added, the dry material and the asphalt mixture are uniform, and the liquid asphalt is evenly coated on the surface of the particles to wet, forming an asphalt bonding layer, combining all materials together to form a uniform plastic paste, which is beneficial to molding;

③ Part of the coal pitch is immersed in the internal space of the carbonaceous material, which further improves the density and cohesiveness of the paste.

Forming: The forming of carbon materials refers to the process of plastically deforming the kneaded carbon paste under the external force of the forming equipment to finally form a green body (or original product) with a certain shape, size, density and strength. Molding type, equipment and products: molding method, general equipment, main products, molding vertical hydraulic press, low-grade sub-fine structure graphite electric carbon extrusion horizontal hydraulic extruder screw extruder rp 400 graphite electrode, square rp 400 graphite electrode vibration forming vibration Forming machine aluminum and carbon bricks for blast furnace isostatic pressing isostatic pressing isotropic graphite ☆ extrusion operation

① Cooling material: disc cooling material, cylinder cooling material, kneading cooling material, etc. to remove volatiles, reduce the volatiles to a suitable temperature (degrees Celsius), increase adhesion, and make the paste uniform and easy to form for 20-30 minutes ② Loading: Press Lifting baffle-cutting 2-3 times-4-10mpa compaction

③ Pre-compression: pressure 20-25mpa, time 3-5min, and vacuum at the same time ④ Extrusion: press baffle-5-15mpa extrusion-shear-turn to cooling water tank extrusion process parameters: compression ratio, pressure chamber and Nozzle temperature, cold material temperature, pre-pressing time, extrusion pressure, extrusion speed, cooling water temperature ☑ green body inspection: bulk density, external knocking, analysis 9209 roasting: in a specially designed heating furnace, The process of carbonizing coal tar pitch in green carbon products through high-temperature heat treatment under the protection of the filler. The pitch coke formed by the carbonization of coal tar combines the carbonaceous aggregates and powder particles together. The calcined carbon products have high mechanical strength, low resistivity, good thermal stability and chemical stability. Roasting is one of the main processes in the production of carbon products, and it is also an important part of the three heat treatment processes in the production of rp 400 graphite electrode. The baking cycle is long (according to the furnace type, it is divided into 22-30 days for one baking and 5-20 days for two baking), and high energy consumption. The baking quality of the green body has a certain influence on the quality of the finished product and the production cost. During the roasting process, the coal pitch in the green body is coked, and about 10% of the volatile matter is discharged. At the same time, the volume of coal tar pitch is reduced by 2-3%, and the quality loss is 8-10%.

The physical and chemical properties of carbon billets have also undergone significant changes. As the porosity increases, the bulk density decreases from 1.70g/cm3 to 1.60g/cm3, and the resistivity decreases from about 10000μΩ. M to 40-50μΩ. M. The mechanical strength of the calcined carbon billet is also greatly improved.

The second roasting is a process of carbonizing the pitch immersed in the pores of the roasted product and then roasting it again. RP 400 graphite electrode (except RP) and joint blanks with high bulk density need to be re-baked, and joint blanks also need to be re-baked or re-baked. Roasting furnace main furnace type: continuous operation-ring furnace (with cover, no cover), tunnel kiln intermittent operation: inverted flame furnace, bottom roasting furnace, box roasting furnace ☑ baking curve and maximum temperature: one-time baking Baking-320, 360, 422480 hours, 1250 degrees Celsius Secondary baking-125, 240, 280 hours, degrees Celsius Baked product inspection: external knock, resistivity, bulk density, compressive strength, internal structure analysis Impregnation is to put the carbon material under pressure The process of immersing the liquid-impregnated pitch into the hole of the product’s rp 400 graphite electrode under a certain temperature and pressure in the container. Its purpose is to reduce the porosity of the product, increase the volume density and mechanical strength of the product, and improve the electrical conductivity and thermal conductivity of the product.

The impregnation process and related technical parameters are: baking blanks-surface cleaning-preheating °C, 6-10 hours)-loading into the dipping tank-vacuuming (8-9kpa, 40-50min)-pitch injection °C)-pressurization (1.2-1.5mpa, 3-4h)-Asphalt reflux-cooling (in or outside the tank) impregnation product inspection: impregnation weight gain rate G=(w2-w1)/w1×100% single impregnation weight gain rate ≥14% The weight gain rate of the second immersion ≥9% The weight gain rate of the third immersion ≥5% Graphitization refers to heating the carbon product above 2300℃ in the protective medium of the high-temperature electric furnace to transform the amorphous carbon into the disordered structure It is a high temperature heat treatment process of three-dimensional ordered graphite crystal structure. Planar hexagonal grid layered structure.