Method with the injection feeding technology molten iron pretreatment desulfurizing
Technical field
The present invention relates to a kind of method of molten iron pretreatment desulfurizing, particularly relate to a kind of method with the injection feeding technology molten iron pretreatment desulfurizing, namely coat the cored-wire that magnesium base composite desulfurizing agent is made with Thin Strip Steel, a kind of molten iron pretreatment desulfurizing method of cored-wire feeding molten iron inside, belong to technical field of ferrous metallurgy by wire reel and feeding wire machine.
Background technology
How to reduce cost of investment, exploitation efficiently, molten iron pretreatment desulfurizing technology easily, be the techno-economic question that iron and steel enterprise pays much attention to always.At present, the Hot Metal Desulphurization Pretreatment Technology that iron and steel metallurgical industry generally adopts is taken as the leading factor with winding-up, for example, publication number is a kind of " pulvis of magnesium desulphurization method for molten iron pretreatment and use " that the Chinese invention patent application of CN101161828 provides, be specifically related to the pulvis of magnesium desulphurization method for molten iron pretreatment and use, the pulvis that uses in the method comprises metal magnesium powder, be characterised in that the pulvis that uses also comprises with blast furnace slag and lime as raw material, through material choice, removal of impurities is dry, co-grinding, the pre-molten magnesium desulfurization promotor that the operations such as Passivation Treatment make is carried out desulfurization according to certain ratio mixing or composite blowing with MAGNESIUM METAL pulvis and pre-molten magnesium desulfurization promotor by existing blowing device in molten iron.Carry out desulphurization reaction in the molten iron owing to adopt spray gun under the pressure of carrier gas, the magnesium powder to be sprayed into, so there is following problem:
1., cost of investment is large, a cover injection system cost of investment is more than 1,000 ten thousand yuan;
2., material use efficiency is low, because carrier gas N in the winding-up process
2With the about magnesium metal more than 15% of the reaction meeting loss of magnesium powder, the factors such as splash when adding winding-up make the material effective rate of utilization very low, about about 60%;
3., temperature drop, energy consumption is large;
4., environmental pollution is serious the environmental pollutants that because the magnesium vapor that forms during winding-up is more than 2000 ℃, amount is large, temperature is high, be difficult to process, carry secretly in the steam directly is discharged in the atmosphere, causes very overall situation to pollute.
Injection feeding technology is the refining techniques that grows up in the eighties in 20th century.Because this technology has easy and simple to handle, the characteristics such as equipment is cheap, labor aptitude is strong, yield of alloy is high, the dust incidence is low, accurate composition control, energy-conserving and environment-protective, be rapidly developed abroad, such as the TECPRO company of the SKW company of the Kubo field company of Japan, Germany, the U.S. and Bumham company etc., all carrying out injection feeding technology and processing research, the exploitation and application of magnesium iron technology.
Different according to line feeding link in the bloom production process, can be divided into: 1. ladle feeding line, 2. tundish line feeding, 3. crystallizer line feeding.
Different according to the line feeding purpose, can be divided into:
1. deoxidation: aluminium wire, rare-earth wires or B alloy wire.
2. alloying and trimming: CaSiBa core spun yarn, aluminium, titanium, boron, rare earth etc., improve metallographic structure, control inclusion morphology.
3. nodularization: magnesium base composite filament, Mg alloy wire etc.
4. desulfurization: CaSi silk, magnesium base composite filament etc.
Injection feeding technology is listed in key popularized project during China " 85 ", at present, unit produced by cored-wire and the feeding wire machine industrialization is ripe day by day in field of metallurgy.Injection feeding technology is ripe at aspects such as nodularization, molten iron alloyings, and has received good economic and social benefit.But this technology is badly in need of being applied and promoting in the field of molten iron pretreatment desulfurizing.
Because the problems referred to above have become enterprise development and hindered the significant problem of national economy sustainable development, so the efficient advanced Hot Metal Desulphurization Pretreatment Technology of development of new is one of problem of needing to be resolved hurrily of domestic steel industry.
Summary of the invention
Purpose of the present invention just is to overcome the prior art above shortcomings, problem for existing injection feeding technology sulfur removal technology existence, provided a kind of method with the injection feeding technology molten iron pretreatment desulfurizing capable of being industrialized, namely coat the cored-wire that magnesium base composite desulfurizing agent is made with Thin Strip Steel, cored-wire is fed a kind of molten iron pretreatment desulfurizing method of molten iron inside by wire reel and feeding wire machine.
The technical solution that the present invention provides is: this method with the injection feeding technology molten iron pretreatment desulfurizing, include by line feeding and unwrapping wire Yarn feeding device dimerous, to coat the cored-wire that magnesium base composite desulfurizing agent makes with Thin Strip Steel places on the draw drum of Yarn feeding device, paying out machine aligning through Yarn feeding device is pulled out, enter through conduit and to carry out molten iron pretreatment desulfurizing in the molten iron melt, for add-on and the wire-feeding velocity of controlling wire rod, the counter and the speed controller that show feeding length also are housed on the described Yarn feeding device, be characterized in that catheter port is 400-600mm apart from molten iron melt liquid level distance, 60~80 tons of the molten iron melt qualities of pretreatment desulfurizing, when the molten iron melt temperature is 1300-1400 ℃, wire-feeding velocity is 350~450m/min, the line feeding time is 8~12 minutes, the composition of described magnesium base composite desulfurizing agent by quality % is: magnesium 20-30, calcium oxide 40-50, silicon 5-10, aluminium sesquioxide 10-20.
Purpose to better implement the present invention, the described cored-wire diameter made from Thin Strip Steel coating magnesium base composite desulfurizing agent is 9-12mm, Thin Strip Steel thickness is 0.4mm.
In the technical scheme that the present invention provides, for preventing the splash phenomenon in desulfurization, occurring, should guarantee that metal magnesium powder is no more than sweetening agent 30% (Mass%), and will control the metal magnesium powder granulometric range and can not surpass 1.5mm.
In the technical scheme that the present invention provides, should determine wire-feeding velocity and line feeding time in conjunction with the ladle size (iron water amount) of steel mill.
Compared with prior art, the invention has the beneficial effects as follows:
A, employing injection feeding technology desulfurization technology have successfully carried out industrial experiment in the 80t hot metal ladle, desulfurization degree reaches 84%, not splash, and hot metal temperature drop is little, and the line feeding time is short, and exhaust gas volumn is little.
B, multicomponent composite desulfate heart yearn have stronger sweetening power.
C, compare the advance that possesses skills and economic reasonableness, the characteristics such as process costs is low, easy and simple to handle, energy-saving and cost-reducing with blowing process.
Description of drawings
Accompanying drawing is process flow diagram of the present invention.
Mark among the figure: 1. line feeding platform, 2. draw drum, 3. paying out machine, 4. conduit, 5. steel ladle cover, 6. cored-wire, 7. molten iron melt.
Specific embodiments
Now in conjunction with the accompanying drawings and embodiments, technical scheme of the present invention is described in detail:
20XX tests at certain steelworks, and heat examination 7 stoves are processed 487.2 tons of iron water amounts altogether, and desulfurization degree all reaches more than 84%, technical indicator has reached the parameter request of steel mill, the splash phenomenon not occuring in the use, operate steadily in iron ladle, meets the processing requirement of steel mill fully.
As shown in the figure, this method with the injection feeding technology molten iron pretreatment desulfurizing that the present invention provides, include by line feeding and unwrapping wire Yarn feeding device dimerous, to coat on the draw drum that cored-wire 6 that magnesium base composite desulfurizing agent makes places Yarn feeding device 2 with Thin Strip Steel, paying out machine 3 alignings through Yarn feeding device are pulled out, carry out molten iron pretreatment desulfurizing in conduit 4 enters molten iron melt 7 in the hot metal ladle, wherein conduit 4 ports are 450mm apart from molten iron melt 7 liquid levels distance.
The hot metal pretreatment working method:
A, hot metal ladle enter the station and chemically examine initial sulphur;
B, skim;
C, set wire-feeding velocity according to initial sulphur and target sulphur;
New slag is made on d, line feeding limit, limit;
E, skim;
F, chemical examination stop sulphur;
G, to converter;
The line feeding parameter
Magnesium base composite desulfurizing agent forms
The line feeding operation
A, metal magnesium powder size range 0.3mm-1.5mm, Mg content be greater than 97%, and must carry out the passivation duration of fire resistance at 5-7 about second;
B, other raw material granularity scope 0-2.5mm;
C, carry out line feeding after various raw materials are proportionally stirred.