CN1064896A

CN1064896A - A kind of method of smelting duriron

Info

Publication number: CN1064896A
Application number: CN 92103047
Authority: CN
Inventors: 吴宽鸿; 张惠棠; 刘英杰; 张学军; 赵德香; 王存忠; 田培文
Original assignee: BEIJING COAL CHEMISTRY INST COAL SCIENCES GENERAL INST; Coal Science Research Institute Zaozhuang Coal Coke Chemical Experiment Factory; Central Iron and Steel Research Institute
Current assignee: BEIJING COAL CHEMISTRY INST COAL SCIENCES GENERAL INST; Coal Science Research Institute Zaozhuang Coal Coke Chemical Experiment Factory; Central Iron and Steel Research Institute
Priority date: 1992-05-05
Filing date: 1992-05-05
Publication date: 1992-09-30
Anticipated expiration: 2007-05-05
Also published as: CN1022192C

Abstract

The present invention is a kind of new ferrosilicon smelting method.Its major technique feature is that raw material that smelting duriron adopts and proportioning (weight unit) are: with silica is that 100 (weight unit) are base, iron silicon Jiao 65～90 (weight unit), steel cuttings＜18 (weight cell).Refining iron silicon Jiao's proportioning raw materials (weight %) is: the medium caking coal 60～80% of high volatilization, powdered iron ore 10～39%, ground silica 1～10%.Iron silicon Jiao's coking temperature is 800～1100 ℃.Adopt the inventive method smelting duriron, its effect is that the reductive agent that is consumed is few, the silicon content height in the ferrosilicon, silicon, iron recovery height.

Description

A kind of method of smelting duriron

The invention belongs to the ferroalloy smelting method.Mainly be applicable to the production ferrosilicon.

Traditional ferrosilicon production method is to form in the Shanhai melting of mining and metallurgy electricity with silica, steel cuttings and carbonaceous reductant.Used carbonaceous reductant is a metallurgical coke, also available in addition gas coke, semicoke, blue charcoal and hard coal etc.Steel cuttings mainly is that machinery manufacturing industry is processed the car bits that get off.And the steel cuttings bulk density is little, and it is big to account for volume, transports uneconomical; In addition, the steel cuttings that mechanical workout is got off is generally longer, can not directly use, and fragmentation is difficulty again, and cost is higher.

In the prior art, also useful iron ore pellets, steel rolling iron sheet and block iron ore replace steel cuttings as the ferric charge (Chinese patent CN87106762.5) of producing ferrosilicon.But the used iron ore material of this method is the oxide compound of iron, and in the process of smelting duriron, the oxide compound of these iron of reducing will increase the consumption and the heat of reductive agent, causes power consumption to raise.

The object of the present invention is to provide a kind of its raw material without metallurgical coke, use no or little steel cuttings, and the method for the low production ferrosilicon of cost.

Major technique measure of the present invention is that the production main raw material that ferrosilicon adopted is iron silicon Jiao and silica, does not add or add a small amount of steel cuttings in addition.

Iron silicon Jiao is also contained a certain amount of iron and silicon-dioxide except that carbon containing.This is by the medium caking coal of high volatile, contains Al ₂O ₃Low and contain SiO ₂High powdered iron ore and a certain amount of ground silica after mixing, are refined in not having the pit kiln of recovery and are formed.

For iron silicon Jiao who makes refining has higher reactivity and higher ratio resistance, and broken loss is little, just must adopt lower coking temperature and short coking time.By coal chemistry as can be known, amorphous carbon is not only than resistance height, and reactivity is strong.Coal is exactly the process that decolorizing carbon transforms to graphite by the process that pyrolytic polycondensation becomes coke.The coking temperature is high more, and the time is long more, and then decolorizing carbon transforms many more to graphite in the coal.Therefore, adopt suitable thermal system,, reduce the degree of graphitization of coke as far as possible with lower coking temperature and short coking time.So both can avoid using the high-quality coking coal, and can obtain to satisfy iron alloy again and produce the special-purpose burnt of needs.

In process of coking, a series of pyrolytic polycondensation effects take place in coal, and wherein the volatile matter hydrocarbon polymer produces a large amount of CO and H after cracking ₂Deng gas, form good reducing atmosphere, make the powdered iron ore that is dispersed in the coal have good reductive condition, the ferric oxide in the iron ore is reduced into metallic iron, the reduction ratio of ferric oxide＞95%.And in the reduction process, do not consume the fixed carbon in the coal; Reduction result has strengthened the structural strength of coke.Ground silica does not change in process of coking, but it plays the effect that stops the amorphous carbon greying and improve iron silicon coke ratio resistance.

Iron silicon Jiao is in water quenching process, and the metallic iron part in the coke is oxidized to Fe ₃O ₄, promptly

But because metallic iron is surrounded by the carbon in the coke, put out in the process at water, the reducing gas that water and carbon generated plays a protective role.

Therefore, still have most of metallic iron not oxidized, prove that through x-ray diffraction and chemical analysis the metallic iron in the coke reoxidizes rate＜50%, and do not have ferric metasilicate to exist among iron silicon Jiao.Simultaneously, in process of coking, do not generate ferric metasilicate yet.

When considering iron silicon Jiao's proportioning raw materials, at first consider the content of powdered iron ore in the coal blending, and the content of ground silica will be foundation to guarantee that coke has certain intensity and higher ratio resistance, simultaneously, after also will considering to add powdered iron ore, the residue viscosifying power of coal charge and the intensity of variation of powdered iron ore in process of coking.

In sum, refining iron silicon Jiao's proportioning raw materials (weight %) is: the medium caking coal 60～80% of high volatilization, powdered iron ore 10～39%.Ground silica 1～10%.

The parameter of the medium caking coal of high volatile (butt) is: FC46～64%, and Vdaf28～40%, Aadf 8～14%, and GRI 58～85, Y12～25mm.

Iron silicon Jiao's concrete production method is as follows:

Prepare burden by its proportioning raw materials, and mix, to be mixed evenly after, by travelling belt and transport trolley, compound is sent into the cloth platform, bed thickness 1000～1800mm, the coking of lighting a fire then, 800～1100 ℃ of coking temperature, 850～950 ℃ of best coking temperature, 7～9 days time.After coke was smelt, cold stoking was not come out of the stove immediately, reduced degree of graphitization.

Iron silicon Jiao who is refined according to the method described above contains fixed carbon 45～70%, TFe10～35%, SiO ₂6～20%.

Iron silicon Jiao's physicals is:

Than resistance＞2000 Ω mm ²/ m

Reactive:＞80%

The method of smelting duriron of the present invention is that burnt and silica is a main raw material with iron silicon, does not add or add steel cuttings after a little while in addition, smelts in the mining and metallurgy electric furnace.

The proportioning raw materials of smelting duriron (weight unit) is: be the 100(weight unit with the silica) be base, iron silicon Jiao is 65～90(weight unit), steel cuttings＜18(weight unit).

Wherein iron silicon Jiao is through fragmentation, granularity be 2～15mm account for 80%, granularity is no more than 20% less than 2mm's.

Adopt smelting duriron of the present invention in the ferrosilicon smelting electric furnace of various capacity, to carry out, can produce the ferrosilicon of the various trades mark.

Compared with prior art, the present invention has following characteristics:

First characteristics of smelting duriron method of the present invention are that the reductive agent that is consumed is low, on the same terms, and the silicon content height of ferrosilicon.

Smelted in the kind, the main chemical reactions in the electric furnace is as follows:

Because the Fe that in water quenching process, produces ₃O ₄Be the high dispersing thing of nascent state, in the smelting duriron process, furnace charge promptly is not reduced SiO before dropping to cupola well ₂The CO that produces in the process is reduced into metallic iron, so in the cupola well Fe does not take place ₃O ₄Direct reduction reactor, i.e. Fe ₃O ₄Reduction do not consume charcoal in the coke, and only by reduction SiO ₂The CO that produces just enough reduces Fe ₃O ₄Needs.Because the gas that reaction produces contains CO ₂Higher, combustiblecomponents is low in the plug for outlet gas, and therefore, flame significantly reduces on the fire door face, make the fire door temperature low, not only easy to operate, and because the fire door temperature is low, burnt itself to contain fixed carbon low relatively for iron silicon in addition, contains more inert material, and the burnt coal-fired loss of iron silicon is significantly reduced.For this reason, when the burnt batching of iron silicon, the content of the coal of effect reductive agent can satisfy the requirement of smelting duriron by the lower limit proportioning, thereby has saved the reductive agent consumption.

On the other hand, owing to contain higher SiO among iron silicon Jiao ₂(the SiO in the coal ₂, the SiO in the iron, ore deposit ₂With the SiO in the silica ₂Three's sum surpasses 10%), and high dispersing is in iron silicon Jiao, closely contacts with carbon among iron silicon Jiao, causes the reduction kinetics condition good, very easily is reduced, and improved the silicon content of ferrosilicon under the same conditions.

Second characteristic of smelting duriron method of the present invention are the secondary voltage height, and power consumption is reduced.

Because iron silicon Jiao's ratio resistance is higher than metallurgical coke, adding to smelt does not have high conduction material-steel cuttings in the batching, so the total electrical resistance of furnace charge increases substantially, thereby can adopt than the higher leveled power supply system of common smelting duriron secondary voltage.Because secondary voltage has improved, short network loss is lost and is reduced, so improved electrical efficiency, has increased output, has reduced power consumption.

The 3rd characteristics of smelting duriron method of the present invention are silicon rate of recovery height, and the product silicon content improves.

Because the total resistance of furnace charge increases, then electrode is inserted deeply down, and charge level is low, and heat concentrates on the cupola well bottom, so electric furnace thermo-efficiency height, the tapping temperature height, and the silicon content of not only silicon rate of recovery height, and product improves.

Embodiment

According to the method described in the present invention, 4 crowdes of iron silicon Jiao at first on non-recovery coke oven, have been refined.The chemical ingredients of coal, powdered iron ore and silica that these 4 crowdes of iron silicon Jiao are adopted is respectively at shown in table 1, table 2 and the table 3, and its proportioning raw materials is as shown in table 4, and iron silicon Jiao's who is refined physicals is as shown in table 5.

The coal analysis result of the used coal of table 1

Dry basis ash content Aad %	Butt volatile matter Vdaf %	Butt fixed carbon FC %	Caking index GRI	Thickness of colloidal matter layer y mm
					9.25	31.42	59.33	81.0	15.5

The chemical ingredients of the used powdered iron ore of table 2 (weight %)

TFe	FeO	Al ₂O ₂	CaO	SiO ₂	MnO	S	P ₂O ₅	MgO	Other
										61.00	23.15	0.39	0.39	11.08	0.065	0.055	0.069	2.40	1.401

The chemical ingredients of 3 used silicas (weight %)

SiO ₂	Al ₂O ₂	Fe ₂O ₅	Other
				98.1	0.13	0.09	1.68

Table 4 embodiment refines iron silicon Jiao's proportioning raw materials (weight %)

Lot number	Coal	Powdered iron ore	Ground silica
				1 2 3 4	80 76.19 72.12 66.37	10 19.05 24.04 32.41	10 4.76 3.84 1.22

4 batches of iron silicon of table 5 Jiao's physicals

Adopt above-mentioned 4 crowdes of iron silicon Jiao, be equipped with corresponding silica or a small amount of steel cuttings again, on iron alloy mining and metallurgy electric furnace, smelt corresponding 4 stove ferrosilicon.The proportioning raw materials of 4 stove ferrosilicon (weight unit)) as shown in table 6.

Table 6, the proportioning raw materials (weight unit) of smelting 4 stove ferrosilicon

The heat (batch) number raw material	1	2	3	4
					Iron silicon Jiao	135	145	160	180
Silica	200	200	200	200
					Steel cuttings	／	／	／	36

The chemical ingredients (weight %) of 4 batches of stove ferrosilicon being smelted is as shown in table 7, and the iron of 4 stove ferrosilicon, the silicon rate of recovery are as shown in table 8.

The chemical ingredients (weight %) of table 7 embodiment smelting duriron

Heat (batch) number	The ferrosilicon trade mark	Chemical ingredients (weight %)
											Si	Al	Ca	Mn	Cr	P	S	C	Fe
		1	FeSi90	89.53	2.78	1.05	0.32	0.15	0.04	0.02										0.2	5.91
2	FeSi75										72.72	1.88	0.56	0.26	0.36	0.03	0.02	0.2	23.97
		3	FeSi65	67.18	1.5	1.0	0.52	0.40	0.03	0.02										0.2	29.15
4	FeSi45										43.35	1.5	1.0	0.67	0.40	0.03	0.02	0.2	52.83

Table 8 is smelted iron, the silicon rate of recovery (%) of 4 stove ferrosilicon

The heat (batch) number raw material	1	2	3	4
					Silicon	80.0	88.96	90	92
Iron	92.3	90.4	88.7	86.6

Claims

1, a kind of is the method for the smelting duriron of raw material with silica, carbonaceous reductant and iron ore material, it is characterized in that:

The raw material of A, smelting duriron and proportioning (weight unit) are: with silica is that 100 (weight unit) are base, iron silicon Jiao 65～90 (weight unit), steel cuttings＜18 (weight unit);

B, refining iron silicon Jiao's raw material and proportioning (weight %) are: the medium caking coal 60～80% of high volatilization, powdered iron ore 10～39%, ground silica 1～10%;

C, iron silicon Jiao's coking temperature is 800～1100 ℃.

2, method according to claim 1, the granularity that it is characterized in that iron silicon Jiao be 2～15mm scope account for 80%, granularity is no more than 20% less than 2mm's.

3, method according to claim 1 is characterized in that best coking temperature is 850～950 ℃.

4, method according to claim 1 is characterized in that iron silicon Jiao's chemical ingredients (weight %) is: fixed carbon 45～70%, TFe10～35%, SiO ₂6～20%.