CN109468461B

CN109468461B - High silicon-zirconium alloy and production method thereof

Info

Publication number: CN109468461B
Application number: CN201811379617.3A
Authority: CN
Inventors: 于跃华
Original assignee: Ningxia Lanhu New Material Technology Co ltd
Current assignee: Ningxia Lanhu New Material Technology Co ltd
Priority date: 2018-11-20
Filing date: 2018-11-20
Publication date: 2021-05-14
Anticipated expiration: 2038-11-20
Also published as: CN109468461A

Abstract

The invention provides a high-silicon-zirconium alloy, which comprises the following elements in parts by weight: si: 81-95%, Zr: 1-5%, Ca: 1-3%, Al <1.5%, C < 0.3%, S < 0.05%, P <0.02, and also provides a production method of the high-silicon zirconium alloy, which comprises the following furnace preheating steps: the radius of the electrode in the furnace body in the furnace entering preheating step is r, the circumferential range of one r away from the outer wall of each electrode is a small material area, the circumferential range of one r away from the small material area is a large material area, the range from the large material area to the side wall of the furnace body is a cold material area, the temperatures of the cold material area, the large material area and the small material area are sequentially increased, and when each batch of mixed materials are put into the furnace body, the putting position is close to the junction of the large material area and the cold material area.

Description

High silicon-zirconium alloy and production method thereof

Technical Field

The invention relates to the technical field of alloy smelting, in particular to a high-silicon-zirconium alloy and a production method thereof.

Background

The high silicon-zirconium alloy is a new ferroalloy product different from the common silicon-zirconium alloy produced by a carbothermic process of a submerged arc furnace. As a silicon inoculant, the inoculant has the advantages of good inoculation effect, good section uniformity and small thickness surface hardness difference due to high silicon content. Zirconium is a very strong carbide forming element, increases the austenite base, refines the grains, and thus improves the strength of the cast iron.

The silicon content in the silicon-zirconium alloy produced in the prior art is 70-80%, the improvement of the silicon content in the high-silicon series alloy is the bottleneck technology of the production process, and the problem of how to produce the high-silicon-zirconium alloy and control the impurity content in the high-silicon series alloy to be lower exists in the industry all the time.

Disclosure of Invention

There is a need for a high silicon zirconium alloy.

It is also necessary to provide a production method of the high-silicon-zirconium alloy.

A high silicon zirconium alloy comprises the following elements in percentage by weight: si: 81-95%, Zr: 1-5%, Ca: 1-3%, Al <1.5%, C < 0.3%, S < 0.05%, P < 0.02%.

The production method of the high-silicon-zirconium alloy comprises a furnace preheating step, wherein the furnace preheating step of the mixed material comprises the following steps:

the radius of the electrode in the furnace body is r, the circumference range of r apart from the outer wall of every electrode is the small material district, the circumference range of two r apart from the small material district is the big material district, the scope of big material district to furnace body lateral wall is the cold burden district, and the temperature in cold burden district, big material district, small material district rises in proper order, and when every batch of mixed material drops into the furnace body, the position of dropping into is for being close to big material district and cold burden district juncture.

According to the invention, by controlling the position and the time when the material enters the furnace body molten pool and fully utilizing the temperature of each position in the molten pool, not only can the waste of heat loss be avoided, but also the entering material is preheated at a lower temperature in advance, so that the heat loss and the impact on a thermal field and an electrode caused by overlarge temperature difference are avoided.

The high-silicon-zirconium alloy product is mainly used as an inoculant in the cast iron smelting process.

Drawings

FIG. 1 is a top view of a submerged arc furnace body.

In the figure: furnace body 10, electrode 20, small material district 21, big material district 22, cold burden district 23, triangle district 24, unloading pipe 30.

Detailed Description

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to these drawings without creative efforts.

Referring to fig. 1, an embodiment of the present invention provides a high silicon-zirconium alloy, which contains the following elements in parts by weight: si: 81-95%, Zr: 1-5%, Ca: 1-3%, Al <1.5%, C < 0.3%, S < 0.05%, P < 0.02%.

Further, the element components and the proportion are as follows: si: 81-85%, Zr: 3-5%, Ca: 2-3%, Al <1.5%, C < 0.3%, S < 0.05%, P < 0.02%.

Further, the element components and the proportion are as follows: si: 85-90%, Zr: 2.5-3.5%, Ca: 2-3%, Al <1.5%, C < 0.3%, S < 0.05%, P < 0.02%.

Further, the element components and the proportion are as follows: si: 90-95%, Zr: 1-2%, Ca: 1-2%, Al <1%, C < 0.2%, S < 0.04%, and P < 0.02%.

The invention also provides a production method of the high-silicon-zirconium alloy, and the step of preheating the mixed materials in the furnace comprises the following steps:

the radius of the electrode 20 in the furnace body 10 is r, the circumferential range of one r away from the outer wall of each electrode 20 is a small material area 21, the circumferential range of one r away from the small material area 21 is a large material area 22, the range from the large material area 22 to the side wall of the furnace body 10 is a cold material area 23, the temperatures of the cold material area 23, the large material area 22 and the small material area 21 are sequentially increased, and when each batch of mixed materials are put into the furnace body 10, the putting position is close to the junction of the large material area 22 and the cold material area 23.

The temperature of the cold material area 23, the large material area 22 and the small material area 21 is less than 600 ℃, more than 800 ℃ and more than 1000 ℃ in sequence, the depth of a molten pool of the furnace body 10 is 2-2.3 meters, and the position 1-2 meters below the liquid level of the molten pool is the highest temperature reduction area.

Because the external mixed material is cold material, the temperature is very low, the mixed material is directly put into the furnace, the putting position can not be ensured, if the mixed material is put into the small material area 21, the cold material is contacted with the small material area 21, the temperature difference is large, the mixed material is in temperature fusion with the small material area 21 after being contacted with the small material area 21, the process ensures that a large amount of heat of the small material area 21 is used for preheating the cold material firstly and then melting the cold material again, the heat used for preheating in the small material area 21 is wasted due to the fact that the material cannot be melted, the more serious temperature difference between the cold material and the small material area 21 is large, cold and heat impact is formed, the uniformity of a thermal field is influenced, low-temperature impact is easily caused on the electrode 20, the loss of the electrode 20 is accelerated, the stress damage is caused on the electrode 20 or the furnace body 10, and the service life of the.

Therefore, in the invention, when the material is fed into the furnace, the cold material is controlled to fall into the junction of the large material area 22 and the cold material area 23, wherein the temperature is about 600-.

Further, a material pushing, temperature rising and reducing step is also arranged before the furnace preheating step, and the material pushing, temperature rising and reducing step is as follows: and pushing the mixed material which is fed into the junction of the large material area 22 and the cold material area 23 in the furnace from the previous batch into the large material area 22 and the small material area, so that the mixed material sequentially enters the large material area 22 and the small material area 21, is secondarily preheated, heated and melted in the large material area 22 and the small material area 21, is reduced, and vacates a space for the mixed material of the next batch to enter the furnace.

The material falling into the junction of the large material area 22 and the cold material area 23 is preheated for the first time, when the material in the small material area 21 becomes alloy liquid and flows downwards to cause the sinking of the material surface, the material which is preheated for the second time in the large material area 22 is pushed to the small material area 21 slowly, then the material which falls into the junction of the large material area 22 and the cold material area 23 and is preheated for the first time is pushed to the large material area 22, the cold material is added to the large material area 22 and the cold material area 23 continuously, the material which is preheated for the second time in the large material area 22 is melted at high temperature in the small material area 21, then flows downwards in the small material area 21 and enters a high-temperature reduction area with the highest temperature to carry out reduction reaction to become the alloy liquid.

The invention realizes the primary preheating, the secondary preheating, the heating melting and the high-temperature reduction of the fed materials from low temperature to high temperature.

Further, the number of the electrodes 20 in the furnace body 10 is three, the three electrodes 20 are connected in a triangular shape, a triangular area 24 is formed between the three electrodes 20, the temperature of the triangular area 24 is higher than that of the small material area 21, and a separate blanking pipe 30 is arranged above the triangular area 24 to independently supply materials to the triangular area 24 or add part of furnace materials according to the change of the furnace condition.

Because the triangular area 24 is formed by surrounding three electrodes 20, the temperature is higher than the temperature of the small material area 21, and the area of the triangular area 24 is smaller, the melting speed of the materials at the area is high, the speed of forming the alloy liquid is high, the flowing speed of the alloy liquid to the high-temperature reduction area below is also high, the sinking speed of the liquid surface is high, the liquid surface of the triangular area 24 is lower than that of the small material area 21 or other areas, the triangular area 24 is the area with higher temperature, after the liquid surface sinks, much heat is accumulated at the area, if the materials are not supplemented in time, the heat at the area cannot be fully used for melting the materials, and therefore, the enrichment waste is caused, more seriously, the temperature difference between the high temperature at the area and the small material area 21 at the outer side can cause temperature difference burning loss to the electrodes 20, therefore, the material feeding pipe 30 is independently arranged at the triangular area 24 for timely supplementing the materials, and the heat, the heat cannot be wasted, and the materials which are planned to be put into the junction of the large material area 22 and the cold material area 23 can be shared, so that the time for putting the materials into the furnace is shortened, the material melting unit consumption is reduced, and the cost is reduced.

Further, the falling mode of the material in the blanking pipe 30 is small, multiple and intermittent.

The amount of a small amount of single blanking is not more than 10kg, the times of single blanking are not less than 3 times for a plurality of times, and the time interval between two adjacent blanking is not less than 5min intermittently.

Further, the method also comprises a batching step arranged before the preheating in the furnace, wherein the batching step is as follows: according to the mass proportion of the raw materials, 2600kg of silica: conductive and reducing material 1700 kg: 85kg of zircon: 70kg of limestone, wherein the content of silicon dioxide in silica is more than 98%, the content of zirconium oxide in zirconite is not less than 65%, and the content of calcium carbonate in limestone is not less than 95%.

Further, the conductive and reducing material is a semi-coke and bituminous coal mixed material with a ratio of 1:1-3: 5.

The semi-coke has high fixed carbon, higher calorific value than that of bituminous coal, stronger chemical activity and favorable reduction, and the bituminous coal has high volatile matters and contains caking substances such as tar and the like, so that the bituminous coal is favorable for caking and smoldering materials in a furnace, and the heat loss is reduced, such as the temperature rise of a molten pool in the furnace body 10.

Further, the batching step is operated as follows: the silica is crushed into large blocks of 90-140mm and the conductive and reducing material is small granules of 8-18mm, the silica is first placed in a mixing bin, the conductive and reducing material is then spread on the surface of the silica, and the silica and the conductive and reducing material are mixed through stirring to coat the surface of the silica with the conductive and reducing material.

The conductive and reducing material is wrapped on the surface of the silica to form a conductive layer, the electrode 20 is electrified when the silica is put into the furnace, the silica and other materials in the furnace form a resistor, in order to ensure that the electrode 20 and the massive silica in the furnace are heated fully and melted, the conductive and reducing material wrapped on the surface of the silica can reduce the resistance of the material to form a conductive path, so that the current of the electrode 20 can form a path with the material, and further the material is promoted to be heated and melted;

because the granularity of the conductive and reducing material is smaller than that of silica, when the conductive and reducing material is mixed with silica or other raw materials, the small-grained material is easy to sink to the bottom, so that the conductive and reducing material cannot be uniformly coated on the surface of the silica, and the resistance of the surface of the silica is not uniform or is larger.

The scheme controls the resistance of the material in the furnace to be not too small by controlling the proportion of the conductive and reducing material, and controls the resistance of the material to be not too large by wrapping the conductive and reducing material on the surface of silica, thereby ensuring that the melting speed of the material is in a controllable state.

The silica is broken into larger blocks, the rest raw materials are smaller powder, the large blocks of powder are matched for use, in addition, the conductive and reducing materials are wrapped on the surfaces of the large blocks of silica, the resistance of the materials can be controlled to be proper, more importantly, the large blocks of powder are matched for use, the proper resistance in the furnace body 10 is met, meanwhile, the granularity and the density of the materials are not compact, because the compact materials easily form a pasty layer when being heated in the furnace body 10, the pasty layer easily plugs the surface of a molten pool and obstructs the discharge of generated carbon monoxide, and therefore, carbonaceous materials cannot be discharged in time, the carbon content in alloy liquid is high, and redundant carbon can react with silicon to generate semi-molten materials such as silicon carbide with heavy specific gravity and the like to be deposited at the bottom of the alloy liquid as a lower slag layer to be removed.

In the prior art, the problems often exist, and due to the fact that the material particles are not properly mixed, a pasty layer exists and blocks carbon monoxide from being discharged, the carbon content is high, silicon carbide is generated, and the impurity content in the silicon-zirconium alloy is high.

The method comprises the steps of discharging, slagging and casting, wherein the discharging step comprises the step of arranging a furnace eye at the bottom of a furnace body 10, discharging alloy liquid after high-temperature reduction into a ladle along the furnace eye, the slagging step comprises the step of spraying a slagging agent on the surface of the alloy liquid discharged along the furnace eye along with flow, and simultaneously blowing oxygen to the bottom of the alloy liquid, so that an upper slag layer floating on the surface and a lower slag layer settling on the bottom of the ladle are formed in the ladle, and the upper slag layer is pulled out by a slag rake.

The slag former comprises dolomite powder, quartz sand and fluorite powder, wherein the upper slag layer is calcium silicate with light specific gravity, and the lower slag layer is high-melting-point substances such as silicon carbide semi-molten substances.

During high-temperature reduction, silicon oxide and zirconium oxide in the raw materials are reduced to generate a silicon simple substance and a zirconium simple substance, and the reduced oxygen element reacts with carbon element to generate carbon monoxide which is discharged, so that the probability of generating silicon carbide through the reaction of carbon and silicon is reduced, the content of impurities in the alloy liquid is also reduced, and the content of silicon is increased.

The modules or units in the device of the embodiment of the invention can be combined, divided and deleted according to actual needs.

While the invention has been described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the invention.

Claims

1. A production method of high-silicon-zirconium alloy is characterized by comprising the following steps: the method comprises a step of preheating the mixture in a furnace, wherein the step of preheating the mixture in the furnace comprises the following steps:

the radius of the electrodes in the furnace body is r, the circumferential range of one r away from the outer wall of each electrode is a small material area, the circumferential range of one r away from the small material area is a large material area, the range from the large material area to the side wall of the furnace body is a cold material area, the temperatures of the cold material area, the large material area and the small material area are sequentially increased, and when each batch of mixed materials are put into the furnace body, the putting position is close to the junction of the large material area and the cold material area;

a material pushing, temperature rising and reducing step is also arranged before the step of preheating the mixed material in the furnace, and the step of material pushing, temperature rising and reducing comprises the following steps: pushing the mixed material which is put into the junction of the large material area and the cold material area in the furnace from the previous batch into the large material area and the small material area so that the mixed material of the previous batch sequentially enters the large material area and the small material area, is secondarily preheated, heated and melted in the large material area and the small material area and is reduced, and vacates a space for the mixed material of the next batch to enter the furnace;

the method also comprises the step of batching before the preheating of the furnace, wherein the step of batching is as follows: the operations of the batching step are as follows: crushing silica into blocks of 90-140mm, wherein the conductive and reducing material is small granules of 8-18mm, placing the silica in a mixing bin, spreading the conductive and reducing material on the surface of the silica, and stirring and mixing the silica and the conductive and reducing material to wrap the conductive and reducing material on the surface of the silica;

the high-silicon-zirconium alloy produced by the production method comprises the following elements in parts by weight: si: 81-95%, Zr: 1-5%, Ca: 1-3%, Al <1.5%, C < 0.3%, S < 0.05%, P < 0.02%.

2. The method for producing the high-silicon silicozirconium alloy according to claim 1, wherein: the three electrodes in the furnace body are connected in a triangular mode, the triangular area is formed between the three electrodes, the temperature of the triangular area is higher than that of the small material area, and an independent discharging pipe is arranged above the triangular area, so that independent feeding is facilitated for the triangular area or an additional part of furnace burden is changed according to the furnace condition.

3. The method for producing the high-silicon silicozirconium alloy according to claim 2, wherein: the falling mode of the materials in the blanking pipe is small, multiple and intermittent.

4. The method for producing the high-silicon silicozirconium alloy according to claim 2, wherein: the method also comprises the step of batching before the preheating of the furnace, wherein the step of batching is as follows: according to the mass proportion of the raw materials, 2600kg of silica: conductive and reducing material 1700 kg: 85kg of zircon: 70kg of limestone, wherein the content of silicon dioxide in silica is more than 98%, the content of zirconium oxide in zirconite is not less than 65%, and the content of calcium carbonate in limestone is not less than 95%.

5. The method for producing the high-silicon silicozirconium alloy according to claim 4, wherein: the conductive and reducing material is a semi-coke and bituminous coal mixed material with a ratio of 1:1-3: 5.

6. The method for producing the high-silicon silicozirconium alloy according to claim 2, wherein: the method comprises the steps of discharging, slagging and casting, wherein the discharging step is to arrange a furnace eye at the bottom of a furnace body, discharging alloy liquid after high-temperature reduction into a ladle along the furnace eye, the slagging step is to spray a slagging agent on the surface of the alloy liquid discharged along the furnace eye along with flow, and simultaneously blowing oxygen to the bottom of the alloy liquid, so that an upper slag layer floating on the surface and a lower slag layer settled at the bottom of the ladle are formed in the ladle, a slagging rake is adopted to remove the upper slag layer, the casting step is to cast the alloy liquid in the ladle with the upper slag layer removed into a mold, and when the lower slag layer cast to the bottom of the ladle is exposed, the casting is stopped, and the lower slag layer at the bottom of the ladle is removed, so that the slag layer is prevented from entering the mold.