Steel slag dryer and drying method

Abstract

The invention relates to a steel slag drying machine which comprises a spiral feeder, a shell, a drying bin, an induced draft fan, magnetrons, waveguide tubes, an electric wave channel, a transformer and a stirring disc, the spiral feeder is connected to the top of the shell, the drying bin is arranged in the shell, the stirring disc is arranged at the bottom of the drying bin and driven by a driving motor, and the magnetrons are symmetrically arranged on the two sides of the drying bin. A waveguide tube is installed at the tail of the magnetron and installed in an electric wave channel, the electric wave channel is arranged on the outer side of the wall of the drying bin, air outlets communicated with the outside are formed in the shell and the wall of the drying bin, and induced draft fans are arranged on the air outlets. An air inlet is formed in the top of the shell and communicates with the interior of the drying bin, and a transformer is arranged at the bottom in the shell. The frequency of the magnetron of the steel slag dryer is matched with the melting point of the steel slag, the heating process of the steel slag is finely controlled, and water in the steel slag is evenly evaporated.

Description

Technical Field

[0001] The invention relates to the technical field of electroslag remelting slag drying, in particular to a steel slag drying machine. Background Art

[0002] In traditional industrial processing, the drying methods for electroslag remelting slag are relatively limited. Natural air drying is a common method, but this method is extremely inefficient and severely restricted by weather conditions, and cannot meet the large-scale and high-efficiency production needs of modern industry. First, dry steel slag can provide stable chemical composition and physical properties. If the steel slag contains water, the rapid evaporation of water at high temperature will cause fluctuations in the composition of the steel slag, affect the stability of the slag system, and then interfere with the refining effect of electroslag remelting and the metal solidification process, which may lead to a decrease in the quality of the ingot, such as looseness, segregation and other defects. Secondly, the presence of water will cause violent gasification reactions. This may cause a sudden increase in local pressure and cause splashing, which will not only cause the loss of steel slag, but also endanger the safety of operators and the normal operation of equipment. Moreover, dry steel slag helps to optimize the input of electrical energy and heat distribution. Steel slag containing water will absorb additional heat for evaporation of water, reducing the proportion of effective heat used for slag and refining, thereby increasing energy consumption and reducing production efficiency. Some dryers put into use early have many defects in processing electroslag remelting slag. For example, the heating method of some dryers is not uniform enough, which leads to local overheating or insufficient drying of the electroslag remelting slag during the drying process. Local overheating may destroy the physical and chemical properties of the slag and affect its subsequent utilization value; while insufficient drying will cause a large amount of moisture to remain in the slag, increasing the cost of transportation and storage. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a steel slag drying machine to make the moisture inside the steel slag evaporate evenly.

[0004] To achieve the above object, the present invention adopts the following technical solutions:

[0005] A steel slag dryer comprises a spiral feeder, a shell, a drying bin, an induced draft fan, a magnetron, a waveguide tube, an electric wave channel, a transformer and a stirring plate. The spiral feeder is connected to the top of the shell, a drying bin is arranged in the shell, a stirring plate is arranged at the bottom of the drying bin, the stirring plate is driven by a driving motor, magnetrons are symmetrically arranged on both sides of the drying bin, a waveguide tube is installed at the tail of the magnetron, the waveguide tube is installed in the electric wave channel, the electric wave channel is arranged on the outside of the drying bin wall, an air outlet connected to the outside is arranged on the shell and the drying bin wall, an induced draft fan is arranged on the air outlet; an air inlet is arranged on the top of the shell and connected to the inside of the drying bin, and a transformer is arranged at the bottom of the shell.

[0006] The inlet of the screw feeder is connected to the feed bin, and the outlet of the screw feeder is connected to the feed port of the drying bin.

[0007] The inner wall of the drying bin is made of ceramic.

[0008] A stirring rod is connected above the stirring disk. The stirring rod and the stirring disk are made of the same material, both made of microcrystalline glass. The stirring rod is connected to the stirring disk through bolts, and a temperature sensor is installed in the center of the stirring disk.

[0009] A ring gear of an annular structure is arranged at the lower edge of the stirring disk, a driving shaft of the driving motor is connected with a driving gear, and the driving gear is meshed with the ring gear installed on the stirring disk.

[0010] The air inlet hole is arranged right above the induced draft fan, a filter screen is arranged on the air inlet hole, and the bottom of the air inlet hole is funnel-shaped.

[0011] The transformer is connected to an external power source.

[0012] A method for drying steel slag in a steel slag dryer, wherein the steel slag is placed in a feed bin and transported to a drying bin through a screw feeder, wherein the air flow velocity inside the drying bin is 0.3 m / s to 0.7 m / s;

[0013] The magnetron frequency is calculated according to the formula f = 0.018T + 0.2d-10; T: melting point of steel slag; d: average particle size of steel slag; according to the formula Calculate the total drying time. M: slag mass;

[0014] The drying temperature is 50℃~100℃, and the magnetron frequency and induced draft fan speed are adjusted according to the temperature;

[0015] S1: When heating up, the power of the magnetron is adjusted to 100%, and the speed of the induced draft fan is modulated to 2000r / min;

[0016] S2: When the temperature monitored by the temperature sensor is at the lowest drying temperature ~ 70°C, the magnetron power is adjusted to 80% and the induced draft fan speed is modulated to 3000r / min;

[0017] S3: When the temperature monitored by the temperature sensor is between 70℃ and 85℃, the power of the magnetron is adjusted to 60% and the speed of the induced draft fan is modulated to 4000r / min;

[0018] S4: When the temperature monitored by the temperature sensor reaches the maximum drying temperature, the magnetron stops running;

[0019] S5: When the temperature drops below the minimum drying temperature again, the magnetron resumes operation and is controlled according to S1-S4.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] The frequency of the magnetron of the steel slag dryer of the present invention is matched with the melting point of the steel slag, and the heating process of the steel slag is finely controlled. The moisture in the steel slag exists in a relatively complex form, including both moisture adsorbed on the surface and moisture contained in the internal pores. Accurate frequency adjustment can make the moisture inside the steel slag evaporate evenly, avoiding the situation where the surface is dry and the inside is wet, and ensuring the overall drying quality of the steel slag. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a structural schematic diagram of the present invention.

[0023] Figure 2 It is a top view of the present invention.

[0024] In the figure: screw feeder 1, shell 2, drying chamber 3, induced draft fan 21, magnetron 22, waveguide tube 28, radio wave channel 23, transformer 24, stirring plate 25, induced draft fan 26, drying chamber feed port 27, waveguide tube 28, stirring rod 29, temperature sensor 30, drive motor 31, air inlet 32. DETAILED DESCRIPTION

[0025] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0026] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and the like are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, features defined as "first", "second", and the like may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means more than two.

[0027] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood by specific circumstances.

[0028] like Figure 1-Figure 2 A steel slag dryer comprises a screw feeder 1, a shell 2, a drying bin 3, an induced draft fan 21, a magnetron 22, a waveguide tube 28, an electric wave channel 23, a transformer 24 and a stirring plate 25. The screw feeder 1 is connected to the top of the shell 2. A drying bin 3 is arranged in the shell 2. A stirring plate 25 is arranged at the bottom of the drying bin 3. The stirring plate 25 is driven by a driving motor 31. Magnetrons 22 are symmetrically arranged on both sides of the drying bin 3. A waveguide tube 28 is installed at the tail of the magnetron 22. The waveguide tube 28 is installed in the electric wave channel 23. The electric wave channel 23 is arranged on the outer side of the bin wall of the drying bin 3. An air outlet 21 communicating with the outside is arranged on the shell 1 and the bin wall of the drying bin 3. An induced draft fan 26 is arranged on the air outlet 21. The air inlet 32 ​​communicating with the inside of the drying bin 3 is arranged on the top of the shell 1 for discharging high-temperature and high-humidity gas in the bin. A transformer 24 is arranged at the bottom of the shell 2.

[0029] The inlet of the screw feeder 1 is connected to the feed bin 11 , and the outlet of the screw feeder 1 is connected to the feed port 27 of the drying bin.

[0030] The inner wall of the drying bin 1 is made of ceramic.

[0031] The stirring plate 25 is connected to a stirring rod 29, which is made of the same material as the stirring plate 25, both made of glass-ceramics, and is connected to the stirring plate 25 by bolts, so that it can be replaced in time after being worn; a temperature sensor 30 is installed in the center of the stirring plate 25 to detect the temperature during drying.

[0032] The lower edge of the stirring disc 25 is provided with a ring gear of an annular structure, and the driving shaft of the driving motor 31 is connected to a driving gear, which meshes with the ring gear installed on the stirring disc 25. The rotation speed of the stirring disc is constant at 20r / min.

[0033] The air inlet 32 ​​is arranged just above the induced draft fan 26. A filter is provided on the air inlet 32 ​​to prevent foreign matter from entering. The bottom of the air inlet is funnel-shaped to increase the air flow.

[0034] The transformer 24 is connected to an external power source.

[0035] The housing 2 is made of stainless steel to prevent bumps during use.

[0036] The heating principle of the present invention is that the steel slag absorbs microwave energy and the polar molecules in the steel slag interact with the microwave electromagnetic field. Under the action of the external alternating electromagnetic field, the polar molecules in the steel slag are polarized and change their orientations alternately as the polarity of the external alternating electromagnetic field changes. Such a large number of polar molecules frequently suffer from mutual friction losses, which converts electromagnetic energy into heat energy. The steel slag enters the drying bin and the stirring plate begins to stir. The magnetron frequency and operating time are adjusted, and the magnetron generates an electromagnetic field. When the microwaves reach the drying bin, the water molecules on the surface and inside of the slag will absorb the energy carried by the microwaves. The water molecules that have absorbed the energy will vibrate to evaporate the water vapor, and the airflow generated when the fan is running will drive the water vapor to be discharged along these channels. The purpose of removing water molecules in the slag is achieved.

[0037] These microwaves are guided through the waveguide, with part of them passing through the ceramic side wall of the drying bin to reach the drying bin, and part of them following the radio wave channel to the bottom of the drying bin, and passing through the stirring plate made of microcrystalline glass to reach the inside of the drying bin; the waveguide can effectively transmit microwaves, ensuring that they are evenly distributed in the drying bin, and ensuring that the bottom and all sides of the slag can receive microwaves.

[0038] A method for drying steel slag in a steel slag dryer, wherein the steel slag is added into a drying bin through a spiral feeder from a feed bin, and electromagnetic waves are emitted in the drying bin through two magnetrons, a part of the electromagnetic waves is transmitted to the inner wall of the drying bin through an electric wave channel, and the remaining part is transmitted to the bin through a stirring plate, so that the moisture inside the steel slag evaporates. The stirring plate at the bottom stirs the steel slag in the bin to achieve uniform heating, which is conducive to the evaporation of water molecules. The removal of moisture is mainly based on the thermal effect of electromagnetic waves. Electromagnetic waves have energy, and when they act on steel slag containing moisture, the water molecules therein absorb the energy of the electromagnetic waves and generate vibration and friction. This violent movement of water molecules leads to an increase in internal energy and an increase in temperature. Since the boiling point of water molecules is relatively low, the increase in temperature prompts the water molecules to change from liquid to gas, thereby achieving evaporation and drying of moisture.

[0039] Extensive experimental tests were conducted on steel slag samples with different melting points and particle sizes, and data processing technology was used to analyze them. The corresponding relationship between them was finally determined to be: f = 0.018T + 0.2d-10, and the drying time satisfies the following formula

[0040]

[0041] When facing steel slag with a relatively high melting point, if the working frequency of the magnetron is set at a low level, the energy output will be difficult to meet the demand for rapid melting of the steel slag. This will directly lead to a significant extension of the processing time, and at the same time, energy consumption will also increase sharply. The long processing process not only reduces the overall production efficiency, but also may affect the subsequent production process due to untimely processing, causing a series of chain reactions.

[0042] By accurately and flexibly adjusting the frequency of the magnetron to match the melting point of the slag, the heating process of the slag can be finely controlled. At the same time, accurate frequency adjustment can also make the moisture inside the slag evaporate evenly, avoiding the situation where the surface is dry and the inside is wet, ensuring the overall drying quality of the slag.

[0043] The specific operation is as follows: the slag is placed in the feed bin and transported to the drying bin through a screw feeder. The air flow velocity inside the drying bin is 0.3 m / s to 0.7 m / s.

[0044] The magnetron frequency is calculated according to the formula f = 0.018T + 0.2d-10; T: melting point of steel slag; d: average particle size of steel slag; according to the formula Calculate the total drying time. M: slag mass;

[0045] The drying temperature is 50℃~100℃, and the magnetron frequency and induced draft fan speed are adjusted according to the temperature;

[0046] S1: When heating up, the power of the magnetron is adjusted to 100%, and the speed of the induced draft fan is modulated to 2000r / min;

[0047] S2: When the temperature monitored by the temperature sensor is at the lowest drying temperature ~ 70°C, the magnetron power is adjusted to 80% and the induced draft fan speed is modulated to 3000r / min;

[0048] S3: When the temperature monitored by the temperature sensor is between 70℃ and 85℃, the power of the magnetron is adjusted to 60% and the speed of the induced draft fan is modulated to 4000r / min;

[0049] S4: When the temperature monitored by the temperature sensor reaches the maximum drying temperature, the magnetron stops running;

[0050] S5: When the temperature drops below the minimum drying temperature again, the magnetron resumes operation and is controlled according to S1-S4.

[0051] The preferred embodiments of the present invention are described in detail above in conjunction with the accompanying drawings. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, and these simple modifications all belong to the protection scope of the present invention. It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations. In addition, the various different embodiments of the present invention can also be arbitrarily combined, as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

[0052] In order to make the purpose, technical scheme and technical effect of the present invention clearer, the technical scheme in the embodiment of the present invention is now clearly and completely described. However, the embodiments described below are only part of the embodiments of the present invention, not all of the embodiments. In combination with the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0053] Embodiment 1:

[0054] The melting point of steel slag is 1700K, the average particle size is 8mm, and the mass is 12kg; the drying method of steel slag is:

[0055] According to the formula f = 0.018T + 0.2d-10, the magnetron frequency is calculated to be 22.6kHz. After calculation, for this batch of steel slag with a particle size of 8mm and a drying frequency of 22.6kHz, the formula is used. The calculated drying time is 18 minutes.

[0056] The drying temperature is 60℃~90℃, and the magnetron frequency and induced draft fan speed are adjusted according to the temperature;

[0057] S1: When heating up, the power of the magnetron is adjusted to 100%, and the speed of the induced draft fan is modulated to 2000r / min;

[0058] S2: When the temperature monitored by the temperature sensor is 60-70°C, the power of the magnetron is adjusted to 80% and the speed of the induced draft fan is modulated to 3000r / min;

[0059] S3: When the temperature monitored by the temperature sensor is between 70℃ and 85℃, the power of the magnetron is adjusted to 60% and the speed of the induced draft fan is modulated to 4000r / min;

[0060] S4: When the temperature monitored by the temperature sensor reaches 90°C, the magnetron stops running;

[0061] S5: When the temperature drops below the minimum drying temperature again, the magnetron resumes operation and is controlled according to S1-S4.

[0062] After drying, the steel slag appears drier and looser in appearance.

[0063] Embodiment 2:

[0064] The slag point is 1680K, the average particle size is 7mm, and the mass is 11kg. The drying method of slag:

[0065] According to the formula f = 0.018T + 0.2d-10, the magnetron frequency of steel slag is 22.26kHz, using the formula The calculated drying time is approximately 16.96 minutes.

[0066] The drying temperature is 65℃~85℃, and the magnetron frequency and induced draft fan speed are adjusted according to the temperature;

[0067] S1: When heating up, the power of the magnetron is adjusted to 100%, and the speed of the induced draft fan is modulated to 2000r / min;

[0068] S2: When the temperature monitored by the temperature sensor is 65-70°C, the power of the magnetron is adjusted to 80% and the speed of the induced draft fan is modulated to 3000r / min;

[0069] S3: When the temperature monitored by the temperature sensor is between 70℃ and 85℃, the power of the magnetron is adjusted to 60% and the speed of the induced draft fan is modulated to 4000r / min;

[0070] S4: When the temperature monitored by the temperature sensor reaches 85°C, the magnetron stops running;

[0071] S5: When the temperature drops below the minimum drying temperature again, the magnetron resumes operation and is controlled according to S1-S4.

[0072] After the drying process, the moisture content of the steel slag is significantly reduced. The dried steel slag is introduced into the steelmaking process. The dried steel slag helps to improve the fluidity of the slag and better absorb impurities, thereby improving the quality of steel.

[0073] Embodiment 3:

[0074] The melting point of steel slag is measured to be 1720K, the average particle size is 6mm, and the mass is 10kg.

[0075] According to the formula f = 0.018T + 0.2d-10, the magnetron frequency is calculated to be 23.36kHz. The drying time is approximately 16 minutes.

[0076] The drying temperature is 65℃~95℃, and the magnetron frequency and induced draft fan speed are adjusted according to the temperature;

[0077] S1: When heating up, the power of the magnetron is adjusted to 100%, and the speed of the induced draft fan is modulated to 2000r / min;

[0078] S2: When the temperature monitored by the temperature sensor is 65-70°C, the power of the magnetron is adjusted to 80% and the speed of the induced draft fan is modulated to 3000r / min;

[0079] S3: When the temperature monitored by the temperature sensor is between 70℃ and 85℃, the power of the magnetron is adjusted to 60% and the speed of the induced draft fan is modulated to 4000r / min;

[0080] S4: When the temperature monitored by the temperature sensor reaches 95°C, the magnetron stops running;

[0081] S5: When the temperature drops below the minimum drying temperature again, the magnetron resumes operation and is controlled according to S1-S4.

[0082] The moisture in the slag is largely removed, reaching a dryness level suitable for steelmaking. The texture of the dried slag is more uniform, and the adhesion between particles is significantly reduced.

[0083] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and basic spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A steel slag dryer, characterized in that: It includes a screw feeder, a shell, a drying bin, an induced draft fan, a magnetron, a waveguide tube, an electric wave channel, a transformer and a stirring plate. The screw feeder is connected to the top of the shell. A drying bin is arranged in the shell. A stirring plate is arranged at the bottom of the drying bin. The stirring plate is driven by a driving motor. Magnetrons are symmetrically arranged on both sides of the drying bin. A waveguide tube is installed at the tail of the magnetron. The waveguide tube is installed in the electric wave channel. The electric wave channel is arranged on the outside of the drying bin wall. An air outlet connected to the outside is arranged on the shell and the wall of the drying bin. An induced draft fan is arranged on the air outlet. An air inlet is arranged on the top of the shell and connected to the inside of the drying bin. A transformer is arranged at the bottom of the shell.

2. A steel slag dryer according to claim 1, characterized in that: The inlet of the screw feeder is connected to the feed bin, and the outlet of the screw feeder is connected to the feed port of the drying bin.

3. A steel slag dryer according to claim 1, characterized in that The inner wall of the drying bin is made of ceramic.

4. The steel slag dryer according to claim 1, characterized in that: A stirring rod is connected above the stirring plate. The stirring rod and the stirring plate are made of the same material, both made of microcrystalline glass. The stirring rod is connected to the stirring plate by bolts, and a temperature sensor is installed in the center of the stirring plate.

5. The steel slag dryer according to claim 1, characterized in that: A ring gear of an annular structure is arranged at the lower edge of the stirring disk, a driving shaft of the driving motor is connected with a driving gear, and the driving gear is meshed with the ring gear installed on the stirring disk.

6. The steel slag dryer according to claim 1, characterized in that: The air inlet hole is arranged right above the induced draft fan, a filter screen is arranged on the air inlet hole, and the bottom of the air inlet hole is funnel-shaped.

7. The steel slag dryer according to claim 1, characterized in that: The transformer is connected to an external power source.

8. The method for drying steel slag using a steel slag dryer according to claim 1, characterized in that: The slag is placed in the feed bin and transported to the drying bin through a screw feeder. The air flow rate inside the drying bin is 0.3 m / s to 0.7 m / s. The magnetron frequency is calculated according to the formula f = 0.018T + 0.2d-10; T: melting point of steel slag; d: average particle size of steel slag; according to the formula Calculate the total drying time. M: slag mass; The drying temperature is 50℃~100℃, and the magnetron frequency and induced draft fan speed are adjusted according to the temperature; S1: When heating up, the power of the magnetron is adjusted to 100%, and the speed of the induced draft fan is modulated to 2000r / min; S2: When the temperature monitored by the temperature sensor is at the lowest drying temperature ~ 70°C, the magnetron power is adjusted to 80% and the induced draft fan speed is modulated to 3000r / min; S3: When the temperature monitored by the temperature sensor is between 70℃ and 85℃, the power of the magnetron is adjusted to 60% and the speed of the induced draft fan is modulated to 4000r / min; S4: When the temperature monitored by the temperature sensor reaches the maximum drying temperature, the magnetron stops running; S5: When the temperature drops below the minimum drying temperature again, the magnetron resumes operation and is controlled according to S1-S4.

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