31results about How to "Prevent resulfurization" patented technology

The invention relates to a tundish covering agent for ultra-low carbon steel, belonging to the technical field of steelmaking and continuous casting. The invention mainly solves the technical problem that the high-alkalinity tundish covering agent in the prior art has poor thermal insulation performance and is difficult to meet the continuous casting of ultra-low carbon molten steel. The technical solution adopted in the present invention is: a tundish covering agent for ultra-low carbon steel, the weight percentage of which is composed of: CaO 40-60%, MgO 5-15%, Al 2 o 3 15~30%, SiO 2 8~20%, Ce 2 o 3 1~6%, C<1%, and the rest are unavoidable impurities. The invention is mainly used for heat insulation and heat preservation of molten steel in a tundish when a slab caster casts ultra-low carbon molten steel, and for absorbing inclusions in molten steel.

The invention relates to a slag conglomeration agent applied to hot metal pretreatment magnesium injection deep desulphurization and an application method thereof, which pertain to the technical field of hot metal pretreatment in the steelmaking process. The slag conglomeration agent is sealed and packaged at 3kg to 7kg after magnesium injection or scattered on the slag surface evenly in the formof particulate. The addition amount is 0.5 kg / t to 1.0kg / t iron which contains the following components by the weight percentages: MgO: 32 percent to 40 percent, SiO2: 0.4 percent to 1.1 percent, S: 0.010 percent to 0.025 percent, water: 0 percent to 0.5 percent, and the rest is CaO and inevitable impurities. The weight percentages of various slagging constituents in the slag conglomeration agentare as follows: light-burned dolomite: 85 percent to 100 percent, and quick lime: 0 percent to 15 percent. The slag conglomeration agent has the advantages that: the slag conglomeration agent can be added immediately after magnesium injection to cause slag to form into blocks which are easy to remove, and resulfurization is prevented by adding acid slag conglomeration agent that is generally adopted.

The invention discloses an RH refining desulphurization process of non-oriented electrical steel, belonging to the technical field of steel making. The process comprises the following steps: setting the lift gas flowrate to 1200 NL / min after the entering of the RH, and enhancing the lift gas flowrate to 1600 NL / min 3 minutes later; blowing oxygen to perform the forced decarburization when the vacuum degree is reduced to 2.0 mba, and when the oxygen blowing is finished and the vacuum degree is lower than 2.0 mba, performing the natural decarburization for 20 minutes; adding the aluminum for deoxidation when the vacuum decarburization is finished; and performing the silicon alloying by using the low carbon ferrosilicon, and adding the desulfurizing agent into the vacuum chamber in two timesthrough the RH alloy bin. The circulation time of the test furnace batch is from 10 minutes to 15 minutes. The process provided by the invention has the advantages that the RH device needs no reconstruction, and the operation is simple. The average RH desulphurization degree is 36.7%, and the desulphurization effect is better. The contents of the FeO and the MnO of the ladle slag have significantinfluence on the desulphurization effect, and the enhancing of the alkalinity of the ladle slag can increase the RH desulphurization efficiency as well as reduce the corrosion of the RH device.

The invention discloses a desulfurizer for steelmaking based on calcium oxide and a preparation method thereof. The desulfurizer is prepared from the following raw materials in parts by weight: 30-35 parts of calcium oxide, 15-20 parts of aluminum ash, and 14 parts of iron slag ‑18 parts, 8‑9 parts of calcium difluoride, 6‑8 parts of barium carbonate, 5‑7 parts of attapulgite, 4‑6 parts of boric anhydride, 3‑7 parts of flame retardant silicone grease; the desulfurizer of the present invention It is prepared based on calcium oxide, and aluminum ash and iron slag are added at the same time, which realizes resource reuse and reduces production costs. The desulfurizer has improved purity, stable performance, and good desulfurization effect. Larger contact surface with sodium hydroxide powder, while the stirring tube rotates, it can heat the mixing material 2 and sodium hydroxide powder evenly, so as to speed up the removal of impurities in the iron slag, ensure the purity of the desulfurizer, and improve production efficiency.

The invention discloses a converter furnace steel-making desulfurizing agent and a preparation method thereof. The converter furnace steel-making desulfurizing agent is mainly obtained by evenly mixing the following composition raw materials in parts by weight: calcium oxide, calcium fluoride, barium carbonate, silica, carborundum, attapulgite, boron anhydrous and flame retardant silicone grease.The preparation method is used for the converter furnace steel-making desulfurizing agent which is the desulfurizing agent free from aluminum and can be used for improving the physical, mechanical and technical performances of steel. According to the converter furnace steel-making desulfurizing agent, gas is removed, nonmetal inclusions are changed, and the quality and mechanical performance of furnace steel making can be improved.

Disclosed is a slag conglomeration agent-free sulfur-fixing agent for magnesium-spraying deep desulfurization in the hot metal pretreatment as well as a desulfurization process thereof, belonging to the technique field of hot metal pretreatment in the steelmaking process. The materials of the sulfur-fixing agent include quicklime, light-burned dolomite and fluorite; and are present in weight percentage: quicklime: 57 to 80 percent, light-burned dolomite: 15 to 35 percent, and fluorite: 0 to 8 percent; and chemical constituents of the sulfur-fixing agent comprise, in weight percentage: CaO: 55to 80 percent, MgO: 5 to 25 percent, SiO2: 0 to 9 percent, CaF2: 0 to 8 percent, Al2O3: 0 to 3 percent, MnO: 0 to 2 percent, K2O: <0.30 percent, Na2O: <0.01 percent, S: <0.025 percent, and P2O5: <0.1percent. The materials are added before hot metal charging or in the hot metal charging process of the hot metal pretreatment. Slag of the sulfur-fixing agent added with molten iron for magnesium-spraying pretreatment has strong capacities of sulfur adsorption and fixation, and has rather high viscosity and melting point, is easy in accumulation and agglomeration, the direct slag skimming can be implemented without adding slag conglomeration agent, meanwhile, the resulfurization caused by adding generally adopted acid slag conglomeration agent can be prevented.

The invention discloses a molten iron slag-removal method, and belongs to the field of molten iron desulfurization pretreatment. The molten iron slag-removal method comprises the following steps of: hoisting a roasted hot metal ladle with a slide plate mechanism to a molten iron carrying position through an overhead crane with a weighing device, recording weight of an empty idle, carrying molten iron, and performing temperature measuring and sampling after tapping is completed; then, performing desulfuration according to a normal procedure, and performing temperature measuring and sampling after desulfuration is completed; hoisting the hot metal ladle subjected to desulfuration, and recording weight of the full ladle, thereby obtaining total weight of the molten iron and iron slag; moving a long nozzle to a position above a common hot metal ladle, opening a slide plate, naturally injecting the molten iron into the common hot metal ladle from the long nozzle to perform ladle pouring operation, displaying through a scale of the overhead crane, respectively closing the slide plate once when residual molten iron is 10 ton and 5 ton, and starting a slag-unloading monitoring and control system when the molten iron is reduced to be 10 ton. The molten iron slag-removal method has the advantages of being simple, stable and controllable, getting rid of limitation that technical level of people is depended, and realizing automatic control on stable control. The molten iron slag-removal method guarantees an iron slag separation effect, can realize 100% slag-free control, and prevents reflux to the greatest extent.

The invention discloses a high-performance spray gun for molten iron injection pretreatment. The high-performance spray gun comprises a connection segment, a gun body segment and an injection segment, which are sequentially communicated, wherein a swirling diffuser is arranged between the gun body segment and the injection segment and comprises an upper cone, a cylinder and a lower reversed cone, which are sequentially communicated; 2-4 nozzles are uniformly formed between a main pipe of the spray gun and a seal head in the circumferential direction of the spray gun and positioned in the side wall of the injection segment; swirling pieces obliquely arranged on the outer wall from the top end of the lower reversed cone to the bottom end surface of the injection segment and positioned above the nozzles. By strengthening three key kinetic parameters of molten iron injection pretreatment, the spray gun significantly improves the kinetic conditions of molten iron injection pretreatment and achieves the comprehensive purposes of improving the sulfur removal efficiency of injection pretreatment and the utilization rate of desulfurizer reaction, shortening the injection time and increasing the production capacity of desulfurization equipment.

The invention relates to a tundish covering agent for non-oriented silicon steel, which mainly solves the technical problems that the existing tundish covering agent has high content of impurity elements and poor thermal insulation performance, and is difficult to meet the continuous casting of non-oriented silicon steel. The technical scheme adopted in the present invention is: a tundish covering agent for non-oriented silicon steel, the weight percent of its chemical composition is CaO 40-50%, SiO2 15-25%, Al2O3 5-8%, MgO 5-10%, MgCO3 10~12%, CaCO3 8~10%, CaF2 2~5%, C <1%, Ti<0.06%, P <0.01%, S <0.01%, silicon aluminum magnesium powder 2~5%, silicon aluminum magnesium The mass ratio of silicon, aluminum and magnesium in the powder is 1:2:3, and the rest are unavoidable impurities. The covering agent of the invention has good thermal insulation performance, can effectively absorb inclusions, prevent molten steel from increasing carbon, and is mainly used in the production of non-oriented silicon steel.

The invention belongs to the field of metallurgy, and relates to a cast steel riser covering agent and its preparation and use method. The cast steel riser covering agent includes 15 to 40 parts of aluminum electrolysis waste cathode carbon blocks in 100 parts by mass, 10-35 parts of dolomite, 10-25 parts of vermiculite, 20-40 parts of waste silicon carbide-silicon nitride bricks for aluminum electrolysis; during preparation, the dried raw materials are first crushed and ground, and the particle size is not greater than 2mm; Then weigh each raw material according to the composition quality of the raw materials, then stir evenly, and dry to obtain the casting steel riser covering agent. When in use, the cast steel riser covering agent is added to the ladle to form a slag layer, and finally the thickness of the slag layer is 6-8 cm, the liquid surface of the ladle does not leak red, and the slag layer does not crust. By using the casting steel riser covering agent of the present invention, the heat loss at the top of the riser can be solved, and the solidification speed of the molten steel in the riser can be extended, thereby improving the feeding capacity of the molten steel in the riser, ensuring the process yield of castings, and reducing the risk of leakage. The height of the mouth can save molten steel and ultimately reduce the cost.