CN107267703A - Molten iron dephosphorization device and dephosphorization method for rotary powder injection - Google Patents

Abstract

The invention discloses a molten iron dephosphorization device and a dephosphorization method for rotating powder spraying. Through the rotating powder spraying molten iron dephosphorization device, an inverted T-shaped powder spray gun can be used to realize multi-point simultaneous dephosphorization treatment, and the efficiency of the dephosphorization reaction is improved. Dynamic conditions can effectively improve the dephosphorization rate, accelerate the dephosphorization reaction speed, shorten the dephosphorization treatment time, and reduce investment; the feeding system and injection system can realize automatic control and online adjustment; effectively prevent the clogging of the powder spraying gun, and can realize The powder spray gun automatically removes slag.

Description

Dephosphorization device and dephosphorization method for molten iron with rotary injection powder

technical field

The invention relates to the field of iron and steel metallurgy, in particular to a molten iron dephosphorization device and a dephosphorization method for rotary spraying powder.

Background technique

Phosphorus is a harmful element in most steel types, and it is easy to segregate at grain boundaries, causing low temperature brittleness and temper brittleness of steel. In recent years, with the rapid development of science and technology, users' requirements for steel quality have been continuously improved. For example, for low-temperature steel, marine steel, hydrogen-induced cracking-resistant steel and steel for some thick plates, in addition to requiring extremely low sulfur content, the phosphorus content in steel is also required to be <0.01% or 0.005%.

In addition, in order to reduce the production cost of oxygen converter steel and implement less slag steelmaking, the phosphorus content of molten iron is also required to be <0.015%. Therefore, since the 1980s, many metallurgists have devoted themselves to the research on the pretreatment and dephosphorization of molten iron, and developed various treatment methods.

Hot metal pre-dephosphorization treatment can be divided into oxidative dephosphorization and reductive dephosphorization. At present, the oxidation dephosphorization process is widely used in steel mills. Dephosphorization methods are divided into SARP method, hot metal tank method, ORP method, converter method and NRP method according to different dephosphorization agents. There are two commonly used types: one is dephosphorization in ladle or torpedo car containing molten iron; the other is dephosphorization pretreatment in converter. These two methods have been practically used in industry.

Application No. 201310508854.6 discloses a method named "a method for dephosphorizing molten iron", which is characterized in that the present invention provides a method for dephosphorizing molten iron, which is mainly aimed at dephosphorizing molten iron in large-scale converters. The following steps are adopted: ① Supply oxygen to the surface of molten iron from the top through an oxygen lance, and the oxygen supply intensity varies within the range of 0.8-1.1Nm ³ /t/min; ② Add lime, lightly burnt Dolomite and ore are the main slagging materials for slagging. After slagging, the binary alkalinity (CaO/SiO ₂ ) of the slag is 1.6-2.0; The intensity is 0.25-0.40Nm ³ /t/min. The invention utilizes the low melting point of low-alkalinity slag, the low temperature of molten iron is easy to form slag, promotes slag formation and oxygen supply by using a large amount of ore, and prolongs the blowing time by blowing with low oxygen supply intensity, and realizes slag by stirring with large bottom blowing intensity , Fully mixed between gold and gold to achieve dephosphorization, has the advantages of good dephosphorization effect, less lime consumption, less consumption of auxiliary materials for dephosphorization, and less discharge of steel slag. However, the dephosphorization rate of this method is low, and the investment in equipment transformation is huge.

Contents of the invention

In order to overcome the above-mentioned defects, the present invention provides a molten iron dephosphorization device and dephosphorization method capable of realizing small temperature drop, short processing time, high dephosphorization rate, equipment transformation and small investment in rotary spraying powder.

The object of the invention is achieved by the following technical solutions:

A molten iron dephosphorization device for rotating and spraying powder, characterized in that it includes a lifting device, an anti-splash device, a feeding system, an injection system, a rotating device, and a powder spraying gun; the powder spraying gun is an inverted T shape Hollow pipe, with spray holes at both ends of the pipe head, and refractory material wrapped on the outside; the rotating device includes a rotary joint and a motor with a hollow shaft inside. The upper end of the shaft is connected, the rotary joint is connected to the pipeline in the horizontal direction, and the lower end of the hollow shaft is connected to the upper end of the powder spray gun through a flange; the anti-splash device is a cylinder with a small upper part and a larger lower part. The above pipeline passes through the anti-splash device and communicates with the feeding system and the injection system respectively through metal hoses. The lower surface of the anti-splash device is covered with a layer of refractory material; the anti-splash device is connected with the lifting device, and the anti-splash device , the rotating device, and the powder spraying gun can move up and down with the lifting device; the lifting device includes a support, a lift and a support arm, the support is connected with the anti-splash device, and the support is connected with the lift through the support arm; The flux and the carrier gas in the injection system are blown into the powder spray gun through the rotating device to realize the rotary powder spraying.

The diameter of the lower surface of the splash prevention device is 110-130% of the outer diameter of the tank mouth.

The diameter of the transverse steel pipe of the powder spraying gun is 2/3 to 4/5 of the diameter of the longitudinal steel pipe; the length of the external refractory material is 1/2 to 2/3 of the total length of the powder spraying gun.

A method for dephosphorizing molten iron by rotary spraying powder, characterized in that it comprises the following steps:

1) Dephosphorization of molten iron is carried out after blast furnace tapping;

2) Start the injection system, blow nitrogen or inert gas with a purity of more than 99.9% and a pressure of 0.4 to 0.6 MPa into the molten iron through the powder spray gun, and at the same time open the lifting device to lower the powder spray gun to 400 to 500 mm from the bottom of the molten iron tank, When the powder spray gun reaches the working position, turn on the rotating device, the rotation speed is 10-30 rpm, and start the feeding system at the same time to spray the total amount of dephosphorization agent that needs to be added into the molten iron through the powder spray gun. 0.09~0.125mm, adjust the injection system to adjust the pressure to the working pressure of 0.8~0.9MP until the dephosphorization is completed;

3) After the dephosphorization of molten iron is completed, close the feeding system and start the lifting device to lift the powder spray gun above the molten iron level, adjust the injection system to adjust the pressure to 0.9~1.1MP, and adjust the rotating device to adjust the rotation speed to 30~ 50 revolutions per minute, 1-2 minutes for slag removal and anti-blocking treatment on the powder spray gun;

4) Perform molten iron slag removal treatment and subsequent operations.

The mass ratio of iron oxide-containing waste to lime in the dephosphorization agent is 40-60:60-40, wherein the iron oxide-containing waste has a mass percentage of iron oxide ≥ 85% and calcium oxide in the lime ≥ 90% by mass.

Beneficial effects of the present invention: 1. The present invention adopts a special rotary powder-spraying molten iron dephosphorization device, and utilizes an inverted T-shaped spraying gun to realize multi-point simultaneous dephosphorization treatment, which improves the kinetic conditions of the dephosphorization reaction and effectively improves the dephosphorization process. Phosphorus rate. 2. The present invention adopts the method of rotating and spraying dephosphorizing agent to carry out dephosphorization of molten iron, which can accelerate the dephosphorization reaction speed and shorten the dephosphorization treatment time. 3. The present invention can be realized by partial transformation of the original hot metal desulfurization station, so its equipment transformation and investment are small. 4. The feeding system and injection system of the present invention can realize automatic control and online adjustment. 5. The present invention can effectively prevent the clogging of the powder spraying gun, and can realize the automatic deslagging of the powder spraying gun.

Description of drawings

Fig. 1 is the structural schematic diagram of the molten iron dephosphorization device of rotary injection powder;

Figure 2 is an enlarged view of the direction A of Figure 1;

Among them, 1-bracket; 2-splash prevention device; 3-feeding system; 4-rotating device; 5-hot metal tank; 6-hot metal tank car; 7-dusting gun; 10-support arm; 11-rotary joint; 12-motor; 13-hollow shaft; 14-flange.

detailed description

Describe below in conjunction with specific embodiment:

A molten iron dephosphorization device for rotating and spraying powder, a device for processing molten iron dephosphorization, including a lifting device, an anti-splashing device 2, a feeding system 3, an injection system 8, a rotating device 4, and a powder spraying gun 7; a lifting device Including a support 1, a lift 9 and a support arm 10, the support 1 is connected to the splash prevention device 2, the support 1 is connected to the lift 9 through the support arm 10, and the lift 9 uses a hydraulic system as a driving force; the powder spray gun 7 is an inverted T-shaped hollow tube, with spray holes at both ends of the tube head, and refractory material wrapped on the outside; the rotary device 4 includes a rotary joint 11 and a motor 12 with a hollow shaft 13 inside, and the rotary joint 11 is a three-way structure as a whole. The inner bearing is connected to the upper end of the hollow shaft 13 in the motor 12, the rotary joint is connected to the pipeline in the horizontal direction, and the lower end of the hollow shaft 13 is connected to the upper end of the powder spray gun 7 through the flange 14; The cylinder, the rotating device 4 is located in the anti-splash device 2, the pipeline passes through the anti-splash device 2 and communicates with the feeding system 3 and the injection system 8 through metal hoses, the lower surface of the anti-splash device 2 Cover with a layer of refractory material; the anti-splash device 2 is connected with the lifting device, and the anti-splash device 2, the rotating device 4, and the powder spray gun 7 can all move up and down with the lifting device; the flux and the injection system in the feeding system 3 The carrier gas in 8 is blown into the powder spraying gun 7 through the rotating device 4 to realize rotary powder spraying.

The power and size of the motor are determined according to the specific size and weight of the powder spray gun 7;

The diameter of the lower surface of the anti-splash device 2 is 110% to 130% of the outer diameter of the mouth of the molten iron tank 5;

The inside of the powder spraying gun 7 is made of wear-resistant seamless steel pipe by means of welding, and the diameter of the transverse steel pipe of the T-shaped nozzle is 2/3 to 4/5 of the diameter of the longitudinal steel pipe; the length of the external refractory material is 1% of the total length of the powder spraying gun. /2～2/3.

The molten iron tank car 6 carrying the molten iron tank 5 is driven to the treatment position after the blast furnace is tapped, and the molten iron dephosphorization treatment is carried out by using the rotary spraying powder molten iron dephosphorization device of the present invention.

Example 1:

Using the present invention to carry out the molten iron dephosphorization test, the maximum diameter of the anti-splash device 2 is 110% of the outer diameter of the mouth of the molten iron tank 5, and the powder spray gun 7 is wrapped with refractory material, and the length of the refractory material is 1/2 of the total length of the powder spray gun; Start the injection system 8 to spray nitrogen or inert gas with a purity of 99.9% or more and a pressure of 0.4 MPa into the molten iron through the powder spray gun 7, and at the same time open the elevator 9 to lower the powder spray gun 7 wrapped with refractory material to the bottom of the molten iron tank 5 400mm, when the powder spray gun 7 reaches the working position, turn on the rotating device 4, the rotation speed is 10 rpm, and start the feeding system 3 at the same time to spray the total amount of dephosphorization agent to be added into the molten iron through the powder spray gun 7; The ratio of the dephosphorization agent containing iron oxide waste to lime is 1:1, the content of iron oxide in the iron oxide waste is 85%, the content of calcium oxide in the lime is 90%, and the particle size of the dephosphorization agent is 0.09mm; adjust the injection system 8 to The pressure is adjusted to the working pressure of 0.8MP until the dephosphorization of molten iron is completed. After the dephosphorization of molten iron is completed, close the feeding system 3 and start the elevator 9 to lift the powder spray gun 7 above the liquid level of the molten iron, adjust the injection system 8 to adjust the pressure to 0.9MP, and adjust the rotating device 4 to adjust the rotation speed to 30 rpm /min, carry out 1min slag removal and anti-blocking treatment. After the dephosphorization of molten iron is completed, slag removal is carried out. After the above-mentioned processing is completed, follow-up operations are carried out as usual. The following technical indicators can be achieved by using the above-mentioned process method and device: the temperature drop of molten iron is 62°C, the treatment time is 35 minutes; the dephosphorization rate is 90%

Example 2:

Adopting the present invention to carry out the molten iron dephosphorization test, the maximum diameter of the anti-splash device 2 is 120% of the outer diameter of the mouth of the molten iron tank 5, and the powder spray gun 7 is wrapped with refractory material, and the length of the refractory material is 2/3 of the total length of the powder spray gun; Start the injection system 8 to spray nitrogen or inert gas with a purity of 99.9% or more and a pressure of 0.5 MPa into the molten iron through the powder spray gun 7, and at the same time open the elevator 9 to lower the powder spray gun 7 wrapped with refractory material to the bottom of the molten iron tank 5 450mm, when the powder spray gun 7 reaches the working position, turn on the rotating device 4, the rotation speed is 20 rpm, and start the feeding system 3 at the same time to spray the total amount of dephosphorization agent to be added into the molten iron through the powder spray gun 7; The ratio of the dephosphorization agent containing iron oxide waste to lime is 1:1, the content of iron oxide in the iron oxide waste is 90%, the content of calcium oxide in the lime is 94%, and the particle size of the dephosphorization agent is 0.106mm; adjust the injection system 8 to The pressure is adjusted to the working pressure of 0.9MP until the dephosphorization of molten iron is completed. After the dephosphorization of molten iron is completed, close the feeding system 3 and start the elevator 9 to lift the powder spray gun 7 above the liquid level of the molten iron, adjust the injection system 8 to adjust the pressure to 1.0MP, and adjust the rotating device 4 to adjust the rotation speed to 40 rpm /min, carry out 2min slag removal and anti-blocking treatment. After the dephosphorization of molten iron is completed, slag removal is carried out. After the above-mentioned processing is completed, follow-up operations are carried out as usual. The following technical indicators can be achieved by using the above-mentioned process method and device: the temperature of molten iron is reduced to 60°C, the treatment time is 30 minutes; the dephosphorization rate is 95%

Example 3:

Using the present invention to carry out the molten iron dephosphorization test, the maximum diameter of the anti-splash device 2 is 130% of the outer diameter of the mouth of the molten iron tank 5, and the powder gun 7 is wrapped with refractory material, and the length of the refractory material is 2/3 of the total length of the powder spray gun; Start the injection system 8 to spray nitrogen or inert gas with a purity of 99.9% or more and a pressure of 0.6 MPa into the molten iron through the powder spray gun 7, and at the same time open the elevator 9 to lower the powder spray gun 7 wrapped with refractory material to the bottom of the molten iron tank 5 500mm, when the powder spray gun 7 reaches the working position, turn on the rotating device 4, the rotation speed is 30 rpm, and start the feeding system 3 at the same time to spray the total amount of dephosphorization agent to be added into the molten iron through the powder spray gun 7; The ratio of the dephosphorization agent containing iron oxide waste to lime is 1:1, the content of iron oxide in the iron oxide waste is 95%, the content of calcium oxide in the lime is 98%, and the particle size of the dephosphorization agent is 0.129mm; adjust the injection system to 8 The pressure is adjusted to the working pressure of 0.9MP until the dephosphorization of molten iron is completed. After the molten iron dephosphorization is completed, close the feeding system 3 and start the elevator 9 to lift the powder spray gun 7 above the liquid level of the molten iron, adjust the injection system 8 to adjust the pressure to 1.1MP, and adjust the rotating device 4 to adjust the rotation speed to 50 rpm /min, carry out 2min slag removal and anti-blocking treatment. After the dephosphorization of molten iron is completed, slag removal is carried out. After the above-mentioned processing is completed, follow-up operations are carried out as usual. The following technical indicators can be achieved by using the above-mentioned process method and device: the temperature drop of molten iron is 64°C, the treatment time is 33°C; the dephosphorization rate is 98%

Implementation Effect:

In a steelmaking plant of an iron and steel enterprise, the hot metal dephosphorization method and device of rotating injection powder were used to conduct a hot metal dephosphorization test on a molten iron tank with a capacity of 260t, and good results were obtained, as follows:

Using the present invention to carry out the dephosphorization test of molten steel and hot metal, the dephosphorization rate is 90-98%, with an average of 94.33%, the temperature of molten iron is reduced to 60-64°C, with an average of 62°C; the dephosphorization treatment time of molten iron is 30-35min, with an average of 32.67min The technical indicators of hot metal dephosphorization are controlled stably. Compared with the conventional hot metal dephosphorization process, the dephosphorization rate is increased by 10-15%, the temperature drop is reduced by more than 30°C, and the hot metal dephosphorization treatment time is shortened by more than 60 minutes on average. In a word, compared with conventional molten iron dephosphorization methods, the method for dephosphorizing molten iron using a brand-new rotary injection powder has greatly improved technical indicators such as dephosphorization rate, temperature drop, and treatment time for molten iron dephosphorization. The successful development of the present invention will It is a major innovation in the dephosphorization process of molten iron.

Claims (4)

1. a kind of dephosphorization of molten iron device of rotary blowing pulvis, it is characterised in that：Including lowering or hoisting gear, anti-splash device, feed System, injection system, rotating device, podwer gun；Described podwer gun is inverted T-shaped hollow tube, and tube head two ends carry spray orifice, outside Wrap up refractory material；Described rotating device includes swivel joint and the internal motor for carrying hollow shaft, and swivel joint is generally Three-port structure, internal bearings are connected with the hollow shaft upper end in motor, swivel joint horizontal direction respectively with pipeline communication, it is hollow Axle lower end is connected by flange with podwer gun upper end；The anti-splash device is up-small and down-big cylinder, and rotating device is located at anti- In spraying and splashing facility, described pipeline respectively with feeding system and injection system is connected through anti-splash device and by metal hose Logical, anti-splash device lower surface covers one layer of refractory material；Anti-splash device is connected with lowering or hoisting gear, anti-splash device, rotation Device, podwer gun can be moved with lowering or hoisting gear oscilaltion；Described lowering or hoisting gear includes support, lift and support arm, Support is connected with anti-splash device, and support is connected by support arm with lift；In flux and injection system in feeding system Carrier gas podwer gun is blown into by rotating device, realize rotating injecting powder.

2. a kind of dephosphorization of molten iron device of rotary blowing pulvis according to claim 1, it is characterised in that：The antispray The 110~130% of a diameter of tank mouth external diameter of device lower surface.

3. a kind of dephosphorization of molten iron device of rotary blowing pulvis according to claim 1, it is characterised in that：The podwer gun Horizontal diameter of steel tube is the 2/3~4/5 of longitudinal diameter of steel tube；Refractory material outside length is the 1/2~2/ of podwer gun total length 3。

4. the dephosphorization method of rotary blowing pulvis dephosphorization of molten iron device described in a kind of application claim 1, it is characterised in that including Following steps：

1) dephosphorization of molten iron processing will be carried out after blast furnace casting；

2) start injection system, be more than 99.9%, 0.4~0.6MPa of pressure nitrogen or inert gas by dusting by purity Rifle is blown into molten iron, drops to podwer gun away from molten iron 400~500mm of pot bottom while opening lowering or hoisting gear, when podwer gun reaches Rotating device is opened during working position, rotary speed is 10~30 revs/min, while the dephosphorization of addition will be needed by starting feeding system Agent total amount is blown into molten iron by podwer gun, and its alloy particle diameter is 0.09~0.125mm, and pressure is adjusted to by adjustment injection system 0.8~0.9MP of operating pressure is until dephosphorization is completed；

3) after the completion of dephosphorization of molten iron, close feeding system and start lowering or hoisting gear podwer gun is promoted to more than molten iron level, adjust Whole injection system adjusts pressure to 0.9~1.1MP, and rotary speed is adjusted to 30~50 revs/min by adjustment rotating device, to spray Powder rifle carries out 1~2min slagging-off and anti-blocking processing；

4) molten iron drossing processing and subsequent operations are carried out；

The mass ratio of waste material containing iron oxide and lime is 40~60 in described Dephosphorising agent:60~40, wherein useless containing iron oxide Expect calcium oxide mass percentage content >=90% in iron oxide mass percentage content >=85%, lime.