A kind of silicon iron product with low content of nitrogen
Technical field
The present invention relates to field of metallurgy, low nitrogen ferrosilicon is mainly used in produces senior electrical steel, because this product does not contain arsenic, antimony, mercury, cadmium, gathers bromine two stupid ethers and gathers objectionable impurities such as bromo biphenyl, only contains lead, the chromium of denier, is a kind of environmentfriendly products therefore.
Background technology
The nitrogen in steel too high levels will cause age hardening; Hardness increases and the ductility variation; Reduce the nitrogen content in the steel, can improve the maximum permeability (magnetic induction density) of siliconized plate, reduce coercive force (iron loss); Will add ferrosilicon during the smelting silicon steel final alloy, content of elements such as the nitrogen in the ferrosilicon, lead, cadmium, arsenic, antimony directly influence the quality and the environmental requirement of silicon steel.Chinese patent 96120093.6,97109344.X, the ferrosilicon that ZL01112586.1 etc. produce are only only considered to reduce impurity such as carbon, titanium, aluminium, calcium to satisfy the requirement of silicon steel in the past; But do not recognize nitrogen, lead, chromium, arsenic, antimony etc. to efficient, the production of high grade silicon steel now and the requirement of environmental protection aspect, cause in the past in the process of producing these products nitrogen a large amount of in starting material, slag former and oxygen, the air, lead, chromium, arsenic, antimony etc. to enter into product, the N in the general high purity ferrosilicon is 100-200ppm; Pb is 20-30ppm, and Cr is 300-500ppm, and As is 10-20ppm; Sb is 10-20ppm; Can not satisfy production and environmental requirement (European Union environmental protection instruction and household electric appliances environmental requirement) efficient now, high grade silicon steel, also not have the ferrosilicon of N≤50ppm to occur so far, the objective of the invention is to provide a kind of and can overcome existing shortcoming of producing the ferrosilicon technology; Can stably produce and contain N≤0.003%; Pb≤0.001%, Cr≤0.015%, Ti≤0.010%; C≤0.012%; Mn≤0.070% does not contain the silicon iron product with low content of nitrogen of arsenic, antimony etc. (in the silicon steel require low more good more) objectionable impurities, demand efficient now to satisfy, that high grade silicon steel is produced.
Summary of the invention
The present invention provides a kind of silicon iron product with low content of nitrogen, and it consists of (wt%): Si 74-80%, and Fe 20-26%, N≤0.003%, Pb≤0.001%, Ti≤0.010%, C≤0.012%, Cr≤0.015%, Mn≤0.070%, surplus is a unavoidable impurities.
In a kind of preferred implementation, the present invention provides a kind of silicon iron product with low content of nitrogen, and it consists of (wt%): Si 74-80%, Fe 20-26%; N≤0.002%, Pb≤0.001%, Ti≤0.008%, C≤0.010%; Cr≤0.010%, Mn≤0.050%, surplus is a unavoidable impurities.
In the another kind of preferred implementation, the present invention provides a kind of silicon iron product with low content of nitrogen, and it consists of (wt%): Si 76-78%, Fe 22-24%; N≤0.002%, Pb≤0.001%, Ti≤0.007%, C≤0.008%; Cr≤0.010%, Mn≤0.035%, surplus is a unavoidable impurities.
Preferred silicon iron product with low content of nitrogen of the present invention do not contain hazardous substance arsenic, antimony, bismuth, tin, mercury, cadmium, gather bromine two stupid ethers and gather bromine and join stupid.
The method production of silicon iron product with low content of nitrogen according to the invention through may further comprise the steps:
(1) raw material is smelted: the electrode paste that adopts Graphite Electrodes or ash content to be not more than 4wt% is made self baking electrode; Smelt adding the hot stove in ore deposit behind siliconized plate, quartzite and the reductive agent mixing; Wherein reductive agent selects ash content to be not more than the refinery coke of 0.3wt%, and the dioxide-containing silica of quartzite is greater than 99wt%;
(2) refining: add dry rice straw 50-100 kilogram when tapping a blast furnace in the bag; After the perfect combustion rice-straw ash is made real; Make it form the thick thermal insulation layer of one deck 20-40cm and isolated on the molten iron surface, open gas bomb then chlorine is imported liquid ferrosilicon from molten iron refining bag bottom through gas permeable brick with air;
(3) the secondary debris retaining is handled: during casting with a wet straw blocking in the refining bag slips mouth, straw blocks at pour point at the back with carbon rod in the ingot mould by the clad compacting, carbon rod is 40-60mm apart from the height of ingot mould.
In a kind of preferred implementation, used refinery coke is not leaded, and the ash content of electrode paste is less than 3%, and titanium content is less than 0.003% and do not contain arsenic, antimony, bismuth, tin in the quartzite, and siliconized plate uses pure oriented silicon steel sheet waste material.
In the another kind of preferred implementation, the used refining encrust of step (2) is made thermal insulation layer with asbestos, and middle one deck refractory brick of building is coated with one deck Graphite Powder 99 as internal layer on the refractory brick, and a kind of integral air brick of resist chemical is equipped with at the bag end.
In the another kind of preferred implementation, the flow of chlorine is 2-5m in the step (2)
3/ h, the time of logical chlorine is 0.5-3 hour.
In the another kind of preferred implementation, it is the pure oriented silicon steel sheet less than 50mm that siliconized plate uses granularity.
In the another kind of preferred implementation, the diameter of carbon rod is 8-15cm in the step (3), and length is 0.5-1.5m.
Smelting operation of the present invention is similar with common ore deposit hot stove production ferro-silicon, and different is: 1. each starting material is required all very strictness, to guarantee nitrogen, lead, chromium, arsenic, objectionable impuritiess such as antimony do not get in the product; 2. chlorine feeds from molten iron refining bag bottom; The refining encrust is made thermal insulation layer with the thick asbestos of 3mm, and middle one deck refractory brick of building is coated with one deck Graphite Powder 99 as internal layer on the refractory brick; To prevent that nitrogen higher in the refractory brick from dissolving in the molten iron, a kind of integral air brick of resist chemical is equipped with at the bag end; 3. guarantee the separation of slag iron and carry out secondary debris retaining processing.
Through N≤0.003% in the ferrosilicon of working method production of the present invention, Pb≤0.001%, Cr≤0.015%, Mn≤0.05%.Utilize this ferrosilicon to produce siliconized plate same level trade mark iron loss and reduce by 15%~25%, magnetic strength improves 0.02~0.04T.Because raw material has passed through selected in the production process; Do not contain lead in the refinery coke; Do not contain arsenic, antimony, bismuth, tin in the quartzite; And the straw that has used cleaning is as lagging material, causes not contain arsenic, antimony, bismuth, tin, mercury, cadmium in this ferrosilicon, gather bromine two stupid ethers and gather the bromo biphenyl objectionable impurities, therefore a kind of especially environmentally friendly machine.
Embodiment:
Embodiment 1:
In the hot stove in 6300KVA ore deposit, adopt ash content be 3.6% and fixed carbon be that 85% electrode paste is made self baking electrode, with dioxide-containing silica be 99.2%, titanium content is 200 kilograms of 0.002% quartzites; 28 kilograms in pure silicon steel disc waste material, ash content are 0.25%, fugitive constituent is 12%, fixed carbon is 95 kilograms of 87% refinery cokes, and the mixing fed to boiler is smelted; Secondary voltage 125V, primary current 400A, the molten iron of will coming out of the stove is then put into the refining bag; Add 70 kilograms of dry rice straw burnings; With spade plant ash are made real, form the thick thermal insulation layer of the about 30cm of one deck, then with 3m
3The flow of/h imported the ferrosilicon melt 1.5 hours through gas permeable brick with chlorine, blocked in the refining bag slips mouth with a big and wet straw handle during casting, and the straw handle is by a clad compacting that 3mm is thick, and ingot mould is interior with a diameter 0.1m; The carbon rod of long 1m blocks in the pour point back, and carbon rod is from the high 50mm of ingot mould, and gauge control is cooled off the back sampling analysis in the 50-70mm scope during casting; Adopt potassium fluoride volumetry to analyze silicon, oxygen-nitrogen analyzer is analyzed nitrogen, and high frequency infrared ray carbon sulphur analyser is analyzed carbon, sulphur, and atomic emission spectrometry (ICP) is analyzed metallic impurity elements such as aluminium, titanium, lead, manganese, chromium; Detected result is Si 76.80%, and Fe 22.98%, and N 0.0025%, Pb0.001%; Cr 0.011%, and Ti 0.0085%, and C 0.010%, and Mn 0.068%; P 0.018%, S0.003%, and Al 0.0088%, and Ca 0.0085%.
Embodiment 2:
In the hot stove in 6300KVA ore deposit, adopt ash content be 2.5% and fixed carbon be that 85% electrode paste is made self baking electrode, with dioxide-containing silica be 99.2%, titanium content is 200 kilograms of 0.002% quartzites, 27 kilograms of pure oriented silicon steel sheet waste materials; Ash content is 0.25%, fugitive constituent is 12%, fixed carbon is 95 kilograms of 87% refinery cokes, and the mixing fed to boiler is smelted, secondary voltage 125V, primary current 400A; The molten iron of will coming out of the stove is then put into the refining bag, adds 80 kilograms of dry rice straw burnings, with spade plant ash is made real, and forms the thick thermal insulation layer of the about 35cm of one deck; Flow with 3m3/h imported the ferrosilicon melt 1.5 hours through gas permeable brick with chlorine then, blocked in the refining bag slips mouth with a big and wet straw handle during casting, and the straw handle is by a clad compacting that 3mm is thick, and ingot mould is interior with a diameter 0.1m; The carbon rod of long 1m blocks in the pour point back, and carbon rod is from the high 50mm of ingot mould, and gauge control is cooled off the back sampling analysis in the 50-70mm scope during casting; Adopt potassium fluoride volumetry to analyze silicon, oxygen-nitrogen analyzer is analyzed nitrogen, and high frequency infrared ray carbon sulphur analyser is analyzed carbon, sulphur, and atomic emission spectrometry (ICP) is analyzed metallic impurity elements such as aluminium, titanium, lead, manganese, chromium; Detected result is Si 77.45%, and Fe 22.28%, N0.0015%; Pb 0.001%, and Cr 0.0095%, and Ti 0.007%; C 0.008%, and Mn 0.035%, P0.013%; S 0.002%, and Al 0.0085%, and Ca 0.0085%.
Comparative Examples
Explained hereafter according to Chinese patent ZL01112586.1 embodiment.In the hot stove in 6300KVA ore deposit, smelt, the ore staple is a dioxide-containing silica 98.8%; Steel cuttings is selected silicon steel bits waste material for use; The refinery coke staple: ash content is 0.2%, and fugitive constituent is 13%, and fixed carbon is 86%; The electrode paste staple is: ash content is 3.2%, and fugitive constituent is 13%, and fixed carbon is 84%; After going into the stove smelting; Obtain the lower liquid ferrosilicon of foreign matter content, strengthen refining further with Impurity removal through two-way pair of gas then, be blown into liquid ferrosilicon through gas permeable brick from platform bag bottom by air compressed and supplied air; Air pressure is regulated by valve; Initiation pressure transfers to 0.1~0.2Mpa, transfers to 0.2~0.3Mpa after 5 minutes, transfers to 0.3~0.4Mpa after 15 minutes; Service life is 60~120 minutes/ton ferrosilicon.Chlorine (or oxygen) is imported the liquid ferrosilicon from the Tai Bao top by carbon tube, and its pressure is adjusted to 0.2~0.4Mpa through valve, and aeration time is 45~100 minutes/ton ferrosilicon.After refining is accomplished, liquid ferrosilicon is injected ingot mould ingot casting, cooling, sampling analysis, finishing is broken, the packing warehouse-in, chemical ingredients is seen table 1.
The chemical ingredients of ferrosilicon (%) after table 1 refining treatment
Element |
Si |
Ti |
C |
Al |
N |
S |
Pb |
Cr |
Mn |
P |
Comparative Examples |
≥ 76 |
< 0.008 |
< 0.008 |
< 0.002 |
0.017 |
< 0.002 |
< 0.001 |
< 0.05 |
0.10 |
< 0.02 |
Embodiment 2 |
77.45 |
0.007 |
0.008 |
0.0085 |
0.0015 |
0.002 |
0.001 |
0.0095 |
0.035 |
0.013 |
The working method of Comparative Examples is to raw-material requirement and basically identicals of the present invention such as quartzite, refinery coke, electrode paste, silicon steel bits; Different just these methods are used pressurized air; Cause nitrogen a large amount of in the pressurized air to get in the ferrosilicon; Because this method is not handled through debris retaining, the product qualified rate of its C≤0.008% is less than 20% simultaneously.It is 170ppm that product is delivered to research institute of Wuhan Iron & Steel (Group) Corp. check nitrogen content; And nitrogen of the present invention only is below the 25ppm.Use this ferrosilicon can only produce IF steel, car and can not produce efficient, high grade silicon steel with steel and common silicon steel.
The silicon iron product of producing with above-mentioned two kinds of methods makes the siliconized plate of the same level trade mark, and its performance is seen table 2.
The silicon iron product that two kinds of methods of table 2 are produced is to the siliconized plate Effect on Performance
Can find out that production same level grade silicon steel uses the low nitrogen ferrosilicon of the present invention can make silicon steel magnetic induction density improve 0.04T, iron loss reduces by 20%.And this product only contain the trace lead, chromium, do not contain objectionable impuritiess such as arsenic, antimony, tin, bismuth, mercury, cadmium, a kind of especially environmentally friendly machine.