CN118532939A

CN118532939A - Spheroidizing furnace for manufacturing silicon micropowder based on self-preheating type heat recycling

Info

Publication number: CN118532939A
Application number: CN202410596439.9A
Authority: CN
Inventors: 张光辉; 汤浩; 黄旭华
Original assignee: Jiangxi Wanji Technology Co ltd; Ji'an Yushun New Material Co ltd
Current assignee: Jiangxi Wanji Technology Co ltd; Ji'an Yushun New Material Co ltd
Priority date: 2024-05-14
Filing date: 2024-05-14
Publication date: 2024-08-23
Anticipated expiration: 2044-05-14
Also published as: CN118532939B

Abstract

The invention discloses a spheroidizing furnace for manufacturing silicon micropowder based on self-preheating heat recycling, wherein the lower end of a straight-through blanking pipe is connected with a spiral blanking pipe communicated with the straight-through blanking pipe, the spiral blanking pipe is positioned in the head end of a smoke exhaust pipe, and the tail end of the spiral blanking pipe extends out of the head end of the smoke exhaust pipe; the middle end of the interior of the smoke exhaust pipe is fixedly provided with a spiral channel, the center of the spiral channel is fixedly provided with a communicating copper pipe, and the two ends of the lower part of the middle end of the smoke exhaust pipe, which are positioned at the communicating copper pipe, respectively penetrate and are fixedly provided with a cold air pipeline II and a hot air pipeline. According to the spheroidizing furnace for manufacturing the silicon micro powder based on self-preheating heat recycling, the spiral blanking pipe is arranged at the lower end of the straight-through type straight-through blanking pipe, so that the silicon micro powder material can slide along the spiral blanking pipe in a spiral manner, the sliding time of the silicon micro powder material is prolonged, and the self-preheating effect is improved.

Description

Spheroidizing furnace for manufacturing silicon micropowder based on self-preheating type heat recycling

Technical Field

The invention relates to a spheroidizing furnace, in particular to a spheroidizing furnace for manufacturing silicon micropowder based on self-preheating heat recycling.

Background

With the rapid development of new material technology, the silicon micropowder is used as an inorganic nonmetallic powder material with excellent performance, and is widely applied to the fields of electronic packaging, ceramics, paint, plastics, rubber, refractory materials and the like. The preparation process of the silicon micro powder has strict requirements on key indexes such as purity, granularity distribution, sphericity, surface property and the like, and the spheroidizing furnace is used as core equipment for producing the silicon micro powder, and links such as structural design, heat management, process control and the like directly influence the quality and production efficiency of products.

The spheroidizing furnace for manufacturing the silicon micropowder on the market mainly faces the following challenges and limitations:

The energy efficiency is low: in the operation process of the traditional spheroidizing furnace, a large amount of heat is always lost along with the emission of flue gas, and cannot be effectively recycled, so that the energy consumption is large, and the modern industrial concept of energy conservation and emission reduction is not met.

The preheating effect is not ideal: before the silicon micropowder enters a high-temperature zone for spheroidization, if preheating is insufficient, the energy consumption required in the melting process is increased, and the spheroidization effect and the product quality can be influenced. However, the existing spheroidizing furnace has a simple preheating treatment mode for the silicon micropowder, and the preheating efficiency and uniformity are required to be improved.

The combustion efficiency is not high: the ratio of combustion-supporting mixed gas (oxygen and combustible gas), blast volume and pressure are not accurate enough, which may lead to insufficient combustion, unstable flame, influence the maintenance of spheroidization temperature and the full spheroidization of the silicon micropowder, and cause energy waste.

The process control is rough: the method is lack of real-time monitoring and fine control on temperature and pressure in the spheroidizing furnace and precise control on material proportion, so that the spheroidizing process is easily influenced by external factors, the fluctuation of product quality is large, and the severe requirements of high-end application fields on the performance of the silicon micropowder are difficult to meet.

The heat energy recovery system is not designed enough: the existing hot flue gas recovery system of the spheroidizing furnace is simple in structure and low in heat exchange efficiency, and cannot fully utilize the waste heat of high-temperature flue gas, so that the overall energy efficiency is low.

Aiming at the problems, the industry is always searching for and improving the design and control strategy of the spheroidizing furnace for manufacturing the silicon micro powder, aiming at improving the combustion efficiency, optimizing the preheating process, enhancing the heat energy recovery capability, precisely controlling the process parameters and precisely controlling the material proportion so as to realize the high efficiency, energy conservation, stability and refinement of the silicon micro powder production. However, the existing improvement measures have certain limitations, the problems cannot be fundamentally solved, and a large technical improvement space still exists.

Under the background, the invention provides a spheroidizing furnace for manufacturing silicon micropowder based on self-preheating type heat recycling and a parameter configuration method thereof, which aims to overcome the defects of the prior art by innovative structural design, accurate process control strategy and efficient heat management means, and provide the spheroidizing furnace for manufacturing silicon micropowder with high combustion efficiency, remarkable preheating effect of the silicon micropowder, improved heat energy recovery efficiency, accurate process control and accurate material proportioning so as to meet the requirements of the modern industry on high-quality and low-energy production of the silicon micropowder.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provide a spheroidizing furnace for manufacturing silicon micropowder based on self-preheating heat recycling so as to solve the problems in the prior art.

The spheroidizing furnace for manufacturing the silicon micro powder based on self-preheating type heat recycling comprises a material powder storage bin, a straight-through blanking pipe, a spheroidizing furnace body and a smoke exhaust pipe, wherein the head end of the smoke exhaust pipe penetrates into the spheroidizing furnace body and is fixed with the spheroidizing furnace body, the straight-through blanking pipe penetrates through and is fixed at the head end of the smoke exhaust pipe, the material powder storage bin is connected to the upper end of the straight-through blanking pipe, and a transition cavity is formed in the middle of the material powder storage bin;

The lower end of the straight-through blanking pipe is connected with a spiral blanking pipe communicated with the straight-through blanking pipe, the spiral blanking pipe is positioned in the head end of the smoke exhaust pipe, and the tail end of the spiral blanking pipe extends out of the head end of the smoke exhaust pipe;

The middle end of the interior of the smoke exhaust pipe is fixedly provided with a spiral channel, a communication copper pipe is fixed at the center of the spiral channel, the lower part of the middle end of the smoke exhaust pipe and the two ends of the communication copper pipe respectively penetrate and are fixedly provided with a cold air pipeline II and a hot air pipeline, and the two ends of the communication copper pipe are respectively communicated with the head ends of the cold air pipeline II and the hot air pipeline.

Preferably, the smoke exhaust pipe is a circular pipeline, and the outer wall of the spiral channel and the inner wall of the smoke exhaust pipe are fixed in a seamless manner.

Preferably, the spheroidizing furnace body is provided with the spray gun assembly, the output end of the spray gun assembly is positioned inside the spheroidizing furnace body, the input end of the spray gun assembly is positioned outside the spheroidizing furnace body, and the spray gun assembly is provided with four groups in an annular distance by taking the geometric center of the horizontal section of the spheroidizing furnace body as the circle center.

Preferably, the spray gun assembly comprises an oxygen pipe and a combustible gas pipeline, wherein the combustible gas pipeline is communicated with the spheroidizing furnace body, and the oxygen pipe is sleeved on the combustible gas pipeline and is communicated with the spheroidizing furnace body.

Preferably, one end of the oxygen pipe is communicated with the tail end of the hot air pipeline.

Preferably, one side of the spheroidizing furnace body and below the transition cavity are provided with a first cold air pipeline, one end of the first cold air pipeline is positioned inside the spheroidizing furnace body, the other end of the first cold air pipeline is communicated with an air conveying pipe, two tail ends of the first cold air pipeline are connected and communicated with the surface of the air conveying pipe, and the other end of the air conveying pipe is connected with a blower.

Preferably, the straight-through blanking pipe and the spiral blanking pipe are of an integrated structure, and graphene heat conduction layers are arranged on the outer walls of the straight-through blanking pipe and the spiral blanking pipe.

Preferably, the outer wall of the communication copper pipe is provided with a graphene heat conduction layer.

Preferably, the parameter configuration method of the spheroidizing furnace comprises the following steps:

Combustion-supporting mixed gas ratio: calculating an optimal oxygen/fuel ratio by a chemical kinetics model; oxygen and combustible gas are respectively fed into an oxygen pipe and a combustible gas pipeline, so that the mixed gas is ensured to reach the set oxygen/fuel ratio;

and (3) controlling the air quantity and the pressure of the blower: calculating the required blast volume and pressure by using Bernoulli equation according to the flow rates of the oxygen pipe and the combustible gas pipeline; starting the blower, adjusting the rotating speed of the blower to provide matched air quantity and pressure, and ensuring that combustion air and combustible gas are uniformly mixed and smoothly ignited in the spray gun assembly;

Setting parameters of a spiral blanking pipe: calculating preheating time required by the silica powder in a preset temperature range, and determining the pitch and the length of the spiral blanking pipe by combining the relation between the pitch and the linear speed;

And (3) building a temperature and pressure control system: installing a temperature and pressure sensor, monitoring the internal state of the spheroidizing furnace body in real time, and setting the upper limit and the lower limit of the temperature and the pressure according to the thermodynamic requirement of the spheroidizing process; a PID controller is adopted to dynamically adjust parameters of oxygen, combustible gas supply and blast volume according to the deviation between the actual measurement value and the set value, so that the spheroidizing furnace is ensured to always operate in the optimal working condition; setting an overrun alarm and protection mechanism;

mass flow control and material proportioning: installing a mass flowmeter at a feed inlet, and accurately measuring the mass flow of each material; through a PLC or DCS system, the feeding speed of each material is automatically adjusted according to a preset formula proportion, and the consistency of components and the quality stability of a final product are ensured;

The spheroidizing process is performed: a. starting a spray gun assembly, igniting the mixed gas of oxygen and combustible gas, releasing a large amount of heat, and calcining the silicon micro powder; b. the silicon micropowder is melted and spheroidized in a high-temperature area to form spheroidized material powder; the spheroidized powder is free floating without being interfered by external force in the downward movement process of the transition cavity 12, so that the uniform distribution of the speed field is ensured; c. the spheroidized powder reaches the first 8 parts of the cold air pipelines and is rapidly cooled to form spherical silicon micropowder products; d. and outputting the cooled spherical silicon micropowder product through a conveying belt at the bottom of the spheroidizing furnace body 3, so as to finish the whole preparation process.

Preferably, the mixed gas is ensured to reach a set oxygen/fuel ratio, in particular: obtaining the optimal oxygen/fuel ratio of the specific combustible gas by using a Levensfiel method, an empirical formula or an experiment, and setting the optimal oxygen/fuel ratio as a target value of a control system; the actual proportion of the mixed gas is monitored in real time, and the supply amount of oxygen and combustible gas is regulated in real time, wherein the regulation index is that the oxygen/fuel ratio is ensured to be the same as or close to the set target value.

Preferably, the preheating time required by the silica powder in a preset temperature range is calculated, and the pitch and the length of the spiral blanking pipe (13) are determined by combining the relation between the pitch and the linear speed, and the method is specifically as follows: the relation between the screw pitch and the linear velocity is v=pi Dn/(6) 0, wherein v is the linear velocity, D is the inner diameter of the spiral blanking pipe, n is the rotating speed of the spiral blanking pipe, the spiral blanking pipe (13) is simulated by fluid mechanics simulation software, the screw pitch and the length of the spiral blanking pipe (13) are optimized according to simulation results, and the optimized evaluation index is that the silicon micro powder is ensured to obtain proper and uniform heat in a preheating stage, the energy consumption required by subsequent melting is reduced, and meanwhile, overheating is avoided.

The beneficial effects are as follows:

1. According to the spheroidizing furnace for manufacturing the silicon micro powder based on self-preheating heat recycling, the spiral blanking pipe is arranged at the lower end of the straight-through type straight-through blanking pipe, so that the silicon micro powder material can slide along the spiral blanking pipe in a spiral manner, the sliding time of the silicon micro powder material is prolonged, and the self-preheating effect is improved;

2. This silicon micropowder makes and uses spheroidizing stove based on self-preheating formula heat cyclic utilization divide into cold air pipeline two and hot air pipeline respectively with a combustion-supporting hot air main pipeline, simultaneously at the intradfixed spiral passageway that sets up of exhaust pipe middle-end, and the fixed intercommunication copper pipe that sets up in spiral passageway center, hot flue gas can be the spiral flow along spiral passageway when passing through spiral passageway like this to this makes hot flue gas be the spiral flow along the intercommunication copper pipe outer wall, makes hot flue gas can be to the comprehensive heating of intercommunication copper pipe, makes to be heated evenly, has improved the air heating effect.

3. The application can realize the technical purpose more accurately, and is specifically expressed as follows:

Combustion efficiency improves: by accurately controlling the oxygen/fuel ratio, the blast volume and the pressure, the efficient and stable combustion process is realized, and the energy waste is reduced.

The preheating effect of the silicon micro powder is obvious: the spiral blanking pipe parameters are scientifically designed, so that the silicon micro powder is ensured to obtain proper and uniform heat in the preheating stage, and the energy consumption required by subsequent melting is reduced.

And the heat energy recovery efficiency is improved: and the design of a heat exchange system of hot flue gas and combustion air is optimized, waste heat resources are effectively utilized, and the energy consumption is further reduced.

The process control is accurate: the temperature and pressure in the furnace are monitored and regulated in real time, so that the spheroidizing process is always in an optimal state, and the product quality and the production stability are improved.

The material proportion is accurate: the mass flow of the silicon micropowder and other additives is accurately controlled, the consistency of the product quality is ensured, and the downstream application requirements are met.

Drawings

FIG. 1 is a schematic diagram of the overall structure of the present invention;

FIG. 2 shows a smoke exhaust pipe according to the present invention a head end cross-sectional schematic;

FIG. 3 is a schematic view of the middle end section of the smoke exhaust pipe of the present invention.

In the figure: 1-material powder storage bin, 2-through blanking pipe, 3-spheroidizing furnace body, 4-oxygen pipe, 5-combustible gas pipeline, 6-blower, 7-air delivery pipe, 8-cold air pipeline I, 9-cold air pipeline II, 10-smoke exhaust pipe, 11-hot air pipeline, 12-transition cavity, 13-spiral blanking pipe, 14-communicated copper pipe and 15-spiral channel.

Detailed Description

Referring to fig. 1-3, a spheroidizing furnace for manufacturing silicon micropowder based on self-preheating heat recycling comprises a powder storage bin 1, a through blanking pipe 2, a spheroidizing furnace body 3 and a smoke exhaust pipe 10, wherein the head end of the smoke exhaust pipe 10 penetrates into the spheroidizing furnace body 3 and is fixed with the spheroidizing furnace body 3, the through blanking pipe 2 penetrates and is fixed at the head end of the smoke exhaust pipe 10, the powder storage bin 1 is connected with the upper end of the through blanking pipe 2, a transition cavity 12 is arranged in the middle of the powder storage bin 1, the lower end of the through blanking pipe 2 is connected with a spiral blanking pipe 13 communicated with the through blanking pipe 13, the spiral blanking pipe 13 is positioned in the head end of the smoke exhaust pipe 10, the tail end of the spiral blanking pipe 13 extends out of the head end of the smoke exhaust pipe 10, the material powder storage bin 1 is used for storing the silicon micro powder, the through blanking pipe 2 is used for discharging the silicon micro powder in the material powder storage bin 1 into the spheroidizing furnace body 3, the silicon micro powder can slide along the spiral blanking pipe 13 in a spiral manner in the process of discharging the silicon micro powder into the spheroidizing furnace body 3, the time for sliding the silicon micro powder is increased, hot smoke in the spheroidizing furnace body 3 can enter the smoke exhaust pipe 10, the tail end of the smoke exhaust pipe 10 is connected with a cyclone dust collector, the spiral blanking pipe 13 is positioned in the smoke exhaust pipe 10, so that the hot smoke can self-preheat the silicon micro powder in the spiral blanking pipe 13, heat recycling is achieved, and compared with the traditional through blanking pipe 2, the self-preheating effect can be improved;

The inside middle-end of exhaust pipe 10 is fixed with spiral passageway 15, exhaust pipe 10 is circular pipeline, spiral passageway 15 outer wall and exhaust pipe 10 inner wall seamless fixation, spiral passageway 15 center department is fixed with intercommunication copper pipe 14, exhaust pipe 10 middle-end lower part just is located the both ends of intercommunication copper pipe 14 and runs through respectively and be fixed with cold air duct two 9 and hot air duct 11, intercommunication copper pipe 14 both ends respectively with cold air duct two 9 and hot air duct 11's head end intercommunication, when hot flue gas flows the exhaust pipe 10 middle-end, can pass spiral passageway 15, and hot flue gas can be along spiral passageway 15 this moment, and spiral passageway 15 center sets up intercommunication copper pipe 14, so hot flue gas is spiral along intercommunication copper pipe 14 outer wall for hot flue gas can be to the comprehensive heating of intercommunication copper pipe 14, makes to be heated evenly, has improved the air heating effect, so further realizes heat cyclic utilization.

The spheroidizing furnace body 3 is provided with a spray gun assembly, the output end of the spray gun assembly is positioned inside the spheroidizing furnace body 3, the input end of the spray gun assembly is positioned outside the spheroidizing furnace body 3, the spray gun assembly is provided with four groups in an annular distance by taking the geometric center of the horizontal section of the spheroidizing furnace body 3 as the center of a circle, the spray gun assembly comprises an oxygen pipe 4 and a combustible gas pipeline 5, the combustible gas pipeline 5 is communicated with the spheroidizing furnace body 3, the oxygen pipe 4 is sleeved on the combustible gas pipeline 5 and is communicated with the spheroidizing furnace body 3, one end of the oxygen pipe 4 is communicated with the tail end of a hot air pipeline 11, one side of the spheroidizing furnace body 3 is positioned below a transition cavity 12, one end of the cold air pipeline 8 is positioned inside the spheroidizing furnace body 3, the other end of the cold air pipeline 8 is communicated with an air conveying pipe 7, the tail end of the second cold air pipeline 9 is connected and communicated with the surface of the air conveying pipeline 7, the other end of the air conveying pipeline 7 is connected with a blower 6, combustion air and combustible gas provided by the oxygen pipe 4 and the combustible gas pipeline 5 are ignited in the spheroidizing furnace body 3, a large amount of heat is released to calcine the silicon micro powder, the silicon micro powder is melted and spheroidized in the area to form spheroidized powder, the temperature in the area is highest, the spheroidized powder is free to float without any external force in the downward movement process of the transition cavity 12, the speed field of the spheroidized powder is uniformly distributed, then the spheroidized powder reaches the first cold air pipeline 8, the spheroidized powder is rapidly cooled, and a spherical silicon micro powder product is obtained and is output through a conveying belt at the bottom of the spheroidizing furnace body 3, and the whole preparation process is completed.

In addition, the straight-through blanking pipe 2 and the spiral blanking pipe 13 are of an integrated structure, graphene heat conduction layers are arranged on the outer walls of the straight-through blanking pipe 2 and the spiral blanking pipe 13, the straight-through blanking pipe 2 and the spiral blanking pipe 13 can be of a welding integrated structure, sealing performance between the straight-through blanking pipe 2 and the spiral blanking pipe 13 can be improved, and graphene heat conduction layers are arranged on the outer walls of the straight-through blanking pipe 2 and the spiral blanking pipe 13, and the graphene heat conduction is far higher than copper or diamond above 5300W/mK, so that heat transfer effects can be enhanced, and heat energy utilization efficiency is improved.

In addition, the outer wall of the communication copper pipe 14 is provided with a graphene heat conduction layer, and the graphene heat conduction layer is arranged on the outer wall of the communication copper pipe 14, so that the heat transfer effect can be enhanced and the heat energy utilization efficiency can be improved because the graphene heat conduction is far higher than copper or diamond above 5300W/mK.

Working principle: firstly, oxygen pipe 4 and combustible gas pipeline 5 provide combustion air and combustible gas are ignited in spheroidizing furnace 3, release a large amount of heat, calcine the silica micropowder, the silica micropowder melts and spheroidizes in this region, form spheroidized material powder, this region temperature is highest, spheroidized material powder does not receive any external force in the in-process of transition chamber 12 downstream, can freely float, the purpose is that its velocity field evenly distributes, then spheroidized material powder arrives cold air pipeline one 8 departments, cool rapidly, obtain spherical silica micropowder product, spherical silica micropowder product is exported through the conveyer belt in the bottom of spheroidizing furnace 3, accomplish whole preparation process, and oxygen pipe 4 and combustible gas pipeline 5 provide combustion air and combustible gas produce a large amount of hot flue gas after burning, hot flue gas can get into exhaust pipe 10 and preheat the silica micropowder that gets into spheroidizing furnace 3 inside through spiral blanking pipe 13, the required heat when the silica micropowder melts, finally the hot flue gas that passes through heat transfer is discharged after cyclone dust collector dust removal from exhaust pipe 10, and cold air pipeline one 8 department is oxygen pipe 6 is provided with combustion air pipe 6, it is through copper pipe 6 and air duct 4 is provided with high temperature and air duct 14 is located inside through two blast blower 6, wherein the high temperature is located in the furnace body 4, the temperature is connected to the inside of the combustion air duct 14 is formed, the combustion air is good for the inside the furnace is cooled down, the temperature is increased, and the inside the combustion air is cooled down, and is cooled down to be cooled down.

In order to realize accurate control, the invention provides a geometric parameter configuration method for a spiral blanking pipe and a spiral channel, and a technological parameter configuration method for a spheroidizing furnace in a spheroidizing process, which specifically comprises the following steps:

1. determination of oxygen to combustible gas ratio

In the combustion-supporting mixed gas provided by the oxygen pipe 4 and the combustible gas pipe 5, the ratio of oxygen to the combustible gas has a direct influence on the combustion efficiency and flame temperature. An optimal oxygen/fuel ratio (O/F ratio) can be calculated by a chemical kinetic model to ensure adequate combustion while avoiding heat loss due to peroxy or under-oxygenation. The optimum oxygen/fuel ratio for a particular combustible gas (e.g., natural gas, propane) can be obtained using the levenspixel method, empirical formula, or experimental determination and set as the target value for the control system.

In the spheroidizing furnace for manufacturing the silicon micropowder, the oxygen/fuel ratio (O/F ratio) of the combustion-supporting mixed gas is precisely controlled to have a critical influence on the combustion efficiency and the flame temperature. In order to ensure adequate combustion while avoiding heat loss due to peroxy or under-oxygenation, the present invention employs a scientific approach of a chemical kinetics model to determine the optimal oxygen/fuel ratio.

The chemical kinetics model is based on chemical reaction kinetics theory, and predicts and optimizes the combustion process by describing the relationship between the combustion reaction rate and the factors such as reactant concentration, temperature, pressure, etc. In the application of the invention, the model can deeply analyze the reaction characteristics of oxygen and combustible gas (such as natural gas, propane and the like) in the spheroidization process of the silicon micropowder, and calculate the ideal oxygen/fuel ratio which can ensure complete combustion and furthest reduce heat loss by taking the factors such as reaction rate, combustion products, thermal effect and the like into consideration.

The optimum oxygen/fuel ratio is obtained by adopting a Levengpiel method, an empirical formula or experimental determination,

In practice, the present invention provides a number of ways to determine the optimal oxygen/fuel ratio for a particular combustible gas:

Levenspixel method: this is an empirical method based on the principles of chemical reaction engineering, by estimating the limiting oxygen concentration and limiting fuel concentration of the combustion reaction, and thus deducing the oxygen/fuel ratio required to achieve maximum combustion rate or maximum thermal efficiency under given conditions. The levenspixel method is suitable for rapid estimation, particularly for processing complex multi-component combustible gas mixtures, and helps to simplify the calculation process and rapidly lock the approximate oxygen/fuel ratio range.

The empirical formula: in industrial practice, a great deal of practical experience has often been accumulated and corresponding empirical formulas have been developed for specific combustible gases. These formulas are generally based on factors such as the chemical composition, physical properties, combustion environment, etc. of the combustible gas, and directly give the optimum oxygen/fuel ratio corresponding thereto. The application of the empirical formula can quickly and conveniently obtain the applicable oxygen/fuel ratio without complex calculation or experiments, but the application of the formula to the current combustible gas species and process conditions is ensured.

Experimental determination: in the case where theoretical models and empirical formulas do not accurately cover a particular operating condition or extremely high accuracy is required, the invention also supports direct determination of the optimal oxygen/fuel ratio by laboratory or field experiments. In the experimental process, the oxygen supply is systematically changed, the change of parameters such as combustion products, flame temperature, combustion efficiency and the like is monitored, and the corresponding oxygen/fuel ratio with the highest heat efficiency or the lowest pollutant emission is found out on the premise of ensuring complete combustion. The experimental determination method has long time consumption, can obtain the optimal oxygen/fuel ratio closest to the actual situation, and has extremely high reference value for novel combustible gas or complex process conditions.

Is set to a target value and precise control is performed,

Whether calculated by a chemical kinetics model or determined by a levenspixel method, an empirical formula or an experiment, the resulting optimal oxygen/fuel ratio is set as a target value for the control system. In the running process of the spheroidizing furnace, the control system can monitor the actual mixing proportion of oxygen and combustible gas in real time, and the supply quantity of the oxygen and the combustible gas is accurately regulated to ensure that the combustion-supporting mixed gas is always kept within the set optimal oxygen/fuel ratio range. The precise control can not only improve the combustion efficiency and reduce the energy waste, but also effectively avoid the problems of peroxidic combustion (large heat loss and possibly harmful nitrogen oxides) caused by overhigh oxygen concentration or under-oxygenic combustion (incomplete combustion and large generation of unburned carbon smoke) caused by overlow oxygen concentration, thereby ensuring the high efficiency, environmental protection and stability of the silicon micropowder spheroidization process.

In summary, the invention scientifically and reasonably determines the optimal oxygen/fuel ratio suitable for specific combustible gas through various ways such as chemical kinetics model calculation, levenspixel method, empirical formula or experimental measurement, and sets the optimal oxygen/fuel ratio as a target value of a control system, thereby realizing the accurate control of the proportion of combustion-supporting mixed gas, remarkably improving the combustion efficiency of the spheroidizing furnace, reducing the heat loss and ensuring the efficient, environment-friendly and stable operation of the silicon micropowder spheroidizing process.

2. Controlling the air quantity and pressure of blower

The air volume and pressure provided by the blower 6 should be matched to the flow rates of the oxygen pipe 4 and the combustible gas conduit 5 to ensure that the combustion air and the combustible gas are uniformly mixed and smoothly ignited in the lance assembly. The required blast volume and pressure can be calculated by Bernoulli's equation or related fluid mechanics model to keep combustion stable and optimize thermal energy utilization. Meanwhile, according to the pressure fluctuation condition in the spheroidizing furnace body 3, the rotating speed of the blower is adjusted in real time to maintain a constant pressure condition.

The bernoulli equation is one of the basic equations in fluid mechanics and reflects the energy conservation relationship between kinetic energy, potential energy, and pressure energy as a fluid moves along a streamline without external work. The air flowing in the closed duct (i.e. the combustion air in the invention) can be regarded as an ideal fluid, the flow of which conforms to the bernoulli equation, and when the bernoulli equation is applied, the oxygen pipe (4) and the inlet of the combustible gas duct (5) and a certain position inside the spray gun assembly are selected as calculation points. The pressure of the combustion air to be supplied by the blower can be calculated by combining the initial static pressure (usually atmospheric pressure) of the air in the pipeline, the density (related to temperature and humidity, and obtained by meteorological data or direct measurement) and the height difference between the two points, with the known flow rate of the mixed gas of oxygen and combustible gas inside the spray gun assembly (measured by a flowmeter) and the required pressure condition (set according to the thermodynamic requirement of the spheroidization process). In combination with the loss of resistance of the conduit between the blower outlet and the lance assembly inlet (calculated by the darcy-Wei Siba hz equation or a related flow resistance coefficient table), the actual pressure value that the blower should provide can be further determined.

Under complex and variable conditions, such as considering the influence of elements such as pipe shape, roughness, bends, valves, etc., the use of bernoulli's equation alone may not be accurate enough. At this point, the air flow in the blower duct can be modeled in detail by means of more complex hydrodynamic models, such as Computational Fluid Dynamics (CFD) software. These models can address non-uniform flow fields, turbulence effects, heat exchange, etc., providing more accurate predictions of flow rate, pressure distribution, and desired blast volume.

In order to keep the pressure in the spheroidizing furnace constant, the invention adopts a strategy for adjusting the rotating speed of the blower in real time. The specific method comprises the following steps:

Pressure monitoring: and installing a pressure sensor at a key position (such as the vicinity of a spray gun assembly) in the spheroidizing furnace body, and monitoring the pressure in the furnace in real time.

Feedback control: and transmitting data acquired by the pressure sensor to a control system (such as a PLC or a DCS), and comparing the data with a set pressure target value.

And (3) rotating speed adjustment: when the actual pressure deviates from the set value, the control system calculates the rotating speed of the blower to be adjusted according to a preset control strategy (such as a PID controller) and sends a command to the blower driving motor.

Motor response: the blower driving motor receives a rotation speed adjusting instruction, correspondingly changes the frequency of the motor, and adjusts the rotation speed of the blower until the pressure in the furnace returns to a set value.

Through the closed-loop control system, the accurate control of the pressure in the spheroidizing furnace body is realized, and the stable proceeding of the combustion process and the high-efficiency utilization of heat energy are ensured. Meanwhile, the real-time adjustment of the rotating speed of the air blower is also beneficial to coping with load changes possibly occurring in the production process, such as raw material supply fluctuation, furnace temperature change and the like, so that the overall adaptability and the operation efficiency of the spheroidizing furnace are enhanced.

3. Setting the pitch and length of the spiral blanking pipe

The pitch and length of the helical blanking pipe 13 directly influence the residence time and preheating effect of the silica powder therein. By calculating the preheating time required by the silicon micro powder in a preset temperature range and combining the relation between the screw pitch and the linear speed (v=pi Dn/60, wherein v is the linear speed, D is the inner diameter of the spiral blanking pipe, and n is the rotating speed of the spiral blanking pipe), the proper screw pitch and length are determined, so that the silicon micro powder is fully preheated without overheating. In addition, the gas-solid two-phase flow in the spiral blanking pipe can be simulated through fluid mechanics simulation software (such as ANSYS Fluent), and the design of the spiral blanking pipe is optimized to improve the preheating uniformity of the silica powder.

The invention adopts fluid mechanics simulation software (such as ANSYS Fluent) to carry out simulation analysis. The method comprises the following specific steps:

and (3) establishing a model: and constructing a three-dimensional geometric model containing gas-solid two-phase flow according to the actual size and structural characteristics of the spiral blanking pipe. The model should detail the key elements such as the shape of the inner wall, the pitch, the pipe diameter, the inlet and outlet conditions of the spiral blanking pipe.

Setting a physical model: physical properties of gas-solid two-phase flow are defined, including physical parameters such as density, viscosity, thermal conductivity, specific heat capacity and the like of gas (hot flue gas) and solid (silicon micropowder), and characteristics such as particle size distribution, initial speed, dispersion state and the like. Meanwhile, an interaction model such as heat transfer, mass transfer and collision, rebound and the like between the gas and the solid and between the particles and the wall surface is arranged.

Boundary condition setting: setting boundary conditions such as temperature, speed distribution and particle concentration of hot flue gas at the inlet of the spiral blanking pipe. The outlet is typically set to a pressure outlet or atmospheric pressure. In addition, considering the influence of the flow of hot smoke in the smoke exhaust pipe, the heat exchange condition of the interface between the spiral blanking pipe and the smoke exhaust pipe needs to be reasonably set.

Numerical solution and result analysis: the modeled model is gridded and numerically solved using selected turbulence models (e.g., RNG k-epsilon model, LES model, etc.) and discrete formats (e.g., finite volume method, finite difference method, etc.). And obtaining the information such as the speed, the temperature distribution, the movement track and the temperature change of the hot smoke in the spiral blanking pipe through calculation.

And (3) design optimization: and according to simulation results, evaluating the influence of the current spiral blanking pipe design on the preheating uniformity of the silica powder. If the problems of partial preheating deficiency or excessive preheating exist, the simulation calculation can be carried out again by adjusting the parameters of the pitch, the pipe diameter, the inlet inclination angle and the like until the ideal preheating effect is obtained. Meanwhile, the stability of gas-solid flow in the spiral blanking pipe is concerned, and adverse phenomena such as particle accumulation and air flow short circuit are avoided.

4. Optimization of heat exchange efficiency of hot flue gas and combustion air

The heat exchange coefficients between the hot flue gas and the communication copper pipe 14, the cold air pipeline II 9 and the hot air pipeline 11 are calculated through a heat transfer mathematical model (such as Newton's law of cooling and Fourier law) so as to determine the optimal heat exchange area, pipeline diameter and material.

The heat exchange coefficients between the hot flue gas and the communication copper pipe 14, the cold air pipeline II 9 and the hot air pipeline 11 are calculated through a heat transfer mathematical model (such as Newton's law of cooling and Fourier law), so that the specific details of the optimal heat exchange area, the pipeline diameter and the material are determined as follows:

and (3) calculating a heat exchange coefficient:

Newton law of cooling: the heat exchanger is suitable for natural convection heat exchange of fluid to a solid surface, and the expression is as follows: q=ha (Th-T infinity), where Q represents the heat exchange amount, h is the natural convection heat exchange coefficient, a is the heat exchange area, th is the hot flue gas temperature, and T infinity is the ambient temperature or the cold air temperature. The natural convection heat transfer coefficient h is usually calculated by referring to a related engineering manual or using empirical formulas, and the formulas may relate to the factors of flue gas flow rate, flue gas density, physical parameters (such as specific heat capacity, heat conductivity coefficient and the like) of hot flue gas and cold air, heat transfer surface shape and size and the like.

Fourier law: the basic law describing the phenomenon of thermal conduction under steady state conditions is expressed as: Wherein q is heat flux density, k is heat conductivity coefficient, A is heat exchange area, Is a temperature gradient. In the heat conduction process between the hot flue gas and the communicated copper pipe, the heat flux density can be determined by measuring or calculating the temperature difference between the flue gas and the wall surface of the copper pipe and the heat conductivity coefficient of the copper pipe, so that the heat exchange quantity is calculated.

And (3) heat exchange area determination:

and (3) communicating the copper pipe 14: and determining the required heat exchange area through an energy balance equation (qin=qout) according to the heat exchange coefficient calculated by combining the newton's law of cooling or the fourier law according to the flow and the temperature of the hot flue gas and the required target temperature of preheating combustion air. Properly increasing the surface area of copper tubes (e.g., increasing tube length or using fin tube structures) can increase heat exchange efficiency, but at the same time, equipment cost and space limitations are required.

Cold air duct two 9 and hot air duct 11: and calculating the heat exchange area by using a heat transfer mathematical model according to the air flow, the initial temperature and the preheating target temperature. Considering that the air flow path is longer, multi-section heat exchange or pipeline inner diameter increase can be adopted to increase the heat exchange area, and meanwhile, the influence of pipeline resistance on the power consumption of the blower is considered.

The diameter and the material selection of the pipeline:

diameter: the diameter of the pipeline not only affects the heat exchange area, but also is closely related to air flow resistance, flow velocity, pressure drop and the like. Reasonable pipeline diameter is determined through hydrodynamic calculation (such as Raney number, darcy-Wei Siba Hertz equation and the like), so that air is ensured to flow in a pipeline at a proper speed, sufficient heat exchange time is ensured, and excessive pressure drop and energy consumption increase caused by too high flow speed are avoided. Meanwhile, the diameter selection also needs to consider the whole layout and the installation space of the equipment.

Material quality: the materials of the copper pipe 14, the cold air pipeline II 9 and the hot air pipeline 11 have good heat conducting performance, high temperature resistance and corrosion resistance. Copper has been used in the present invention as an excellent heat conductive material. If further optimized, the alloy with better heat conduction performance (such as copper-nickel alloy, copper-chromium-zirconium alloy and the like) or the graphene coating can be selected to improve the heat exchange efficiency. Meanwhile, the inner surface and the outer surface of the pipeline should be subjected to antioxidation treatment, so that the material performance is prevented from being reduced in a long-term high-temperature environment.

In summary, by applying the heat transfer mathematical models such as newton's law of cooling and fourier law, and combining the physical parameters, flow rate, temperature requirement and other factors of hot flue gas and cold air, the heat exchange coefficient and heat exchange area are accurately calculated, and the diameter and material of the pipeline are reasonably selected, so that the heat exchange efficiency between the hot flue gas and the pipeline communicating copper pipe and the cold air can be effectively improved, the heat energy recovery effect of the whole spheroidizing furnace is improved, the energy consumption is reduced, and the operation performance of the spheroidizing furnace is accurately controlled and optimized.

In addition, the thickness of the graphene heat conduction layer is adjusted to maximize heat transfer efficiency in consideration of the heat conductivity coefficient of the graphene heat conduction layer. Geometric parameters (such as diameter, length and helix angle) of the spiral channel 15 are set according to the temperature and flow of the hot flue gas and the preheating target temperature of the required combustion air so as to optimize the residence time of the hot flue gas in the spiral channel and the contact area between the hot flue gas and the communicated copper pipe, thereby improving the heat energy recovery efficiency.

5. Temperature and pressure control system design

And (3) establishing a real-time monitoring and controlling system for the temperature and the pressure in the spheroidizing furnace body 3, and setting the upper limit and the lower limit of the temperature and the pressure according to the thermodynamic requirements of the spheroidizing process. And a PID controller or other advanced control strategies are adopted, and parameters of oxygen, combustible gas supply quantity and blast quantity are dynamically adjusted according to the deviation between the actual measurement value and the set value, so that the spheroidizing furnace is ensured to always operate under the optimal working condition. Meanwhile, an overrun alarm and protection mechanism is arranged to prevent safety problems caused by overhigh temperature or overlarge pressure in the furnace.

6. Mass flow control and material proportioning

For the preparation of spheroidized powders, precise control of the mass flow of the silica fume and other additives (if any) is critical. And the mass flowmeter is adopted to accurately measure each material, and the feeding speed of each material is automatically regulated through a PLC (programmable logic controller) or a DCS (distributed control system) according to the preset formula proportion, so that the ingredient consistency and the quality stability of the final product are ensured.

Through the configuration and application of the mathematical relationship, the application can realize the technical purpose more accurately, and is specifically expressed as follows:

Specific implementation steps

Example 1:

Raw material preparation: accurately metering the silicon micro powder according to a preset formula proportion, and placing the silicon micro powder into a material powder storage bin 1;

combustion-supporting mixed gas ratio: calculating an optimal oxygen/fuel ratio (O/F ratio) by a chemical kinetics model, and selecting an optimal ratio suitable for a specific combustible gas; oxygen and combustible gas are respectively fed into an oxygen pipe 4 and a combustible gas pipeline 5, so that the mixed gas reaches the set oxygen/fuel ratio;

And (3) controlling the air quantity and the pressure of the blower: calculating the required blast volume and pressure by using Bernoulli equation according to the flow rates of the oxygen pipe 4 and the combustible gas pipeline 5; starting the blower 6, adjusting the rotating speed to provide matched air quantity and pressure, and ensuring that combustion air and combustible gas are uniformly mixed and smoothly ignited in the spray gun assembly;

Setting parameters of a spiral blanking pipe: calculating the preheating time required by the silica powder in a preset temperature range, and determining the pitch and the length of the spiral blanking pipe 13 by combining the relation (v=pi Dn/60) of the pitch and the linear speed;

Hot flue gas and combustion air and (3) designing a heat exchange system: calculating heat exchange coefficients between the hot flue gas and the communicating copper pipe 14, the cold air pipeline II 9 and the hot air pipeline 11 by utilizing Newton's law of cooling or Fourier's law, determining the optimal heat exchange area, pipeline diameter and material according to the heat exchange coefficients, considering the heat conduction coefficients of the graphene heat conduction layer, adjusting the thickness of the graphene heat conduction layer to maximize heat transfer efficiency, setting the geometric parameters of the spiral channel 15, and optimizing the residence time of the hot flue gas in the spiral channel and the contact area between the hot flue gas and the communicating copper pipe;

And (3) building a temperature and pressure control system: installing a temperature and pressure sensor, monitoring the internal state of the spheroidizing furnace body 3 in real time, and setting the upper limit and the lower limit of the temperature and the pressure according to the thermodynamic requirement of the spheroidizing process; a PID controller is adopted to dynamically adjust parameters of oxygen, combustible gas supply and blast volume according to the deviation between the actual measurement value and the set value, so that the spheroidizing furnace is ensured to always operate in the optimal working condition; setting an overrun alarm and protection mechanism;

The spheroidizing process is performed: a. starting a spray gun assembly, igniting the mixed gas of oxygen and combustible gas, releasing a large amount of heat, and calcining the silicon micro powder; b. the silicon micropowder is melted and spheroidized in a high-temperature area to form spheroidized material powder; the spheroidized powder is free floating without being interfered by external force in the downward movement process of the transition cavity 12, so that the uniform distribution of the speed field is ensured; c. the spheroidized powder reaches the first 8 parts of the cold air pipelines and is rapidly cooled to form spherical silicon micropowder products; d. outputting the cooled spherical silicon micropowder product through a conveying belt at the bottom of the spheroidizing furnace body 3, and completing the whole preparation process;

Example 2:

On the basis of embodiment 1, the following are added to further improve the accuracy and technical effect:

The combustion-supporting mixed gas comprises the following components in percentage by weight: obtaining the optimal oxygen/fuel ratio of the specific combustible gas by using a Levensfiel method, an empirical formula or an experiment, and setting the optimal oxygen/fuel ratio as a target value of a control system; the actual proportion of the mixed gas is monitored in real time, and the supply quantity of oxygen and combustible gas is accurately regulated, so that the combustion-supporting mixed gas is ensured to always keep the optimal proportion, and the combustion efficiency and flame temperature are improved;

And (3) carrying out fine management on air quantity and pressure of a blower: according to the pressure fluctuation condition in the spheroidizing furnace body 3, the rotating speed of the blower 6 is adjusted in real time to maintain a constant pressure condition; the flow of the oxygen pipe 4 and the flow of the combustible gas pipeline 5 are continuously monitored, the blast volume is dynamically adjusted, the combustion air and the combustible gas are ensured to be uniformly mixed in the spray gun assembly, and the heat energy utilization rate is optimized;

optimally designing a spiral blanking pipe: the spiral blanking pipe 13 is simulated by fluid mechanics simulation software, the pitch and the length are further optimized according to simulation results, the proper and uniform heat of the silicon micro powder is ensured to be obtained in a preheating stage, the energy consumption required by subsequent melting is reduced, and meanwhile, overheating is avoided;

And the heat exchange efficiency of the hot flue gas and the combustion air is improved: according to actual operation data, the heat exchange coefficient between the hot flue gas and the communicating copper pipe 14, the cold air pipeline II 9 and the hot air pipeline 11 is calculated again at regular intervals, and the heat exchange area, the pipeline diameter, the geometric parameters of the spiral channel 15 and the thickness of the graphene heat conduction layer are adjusted timely so as to adapt to process change and equipment aging factors and continuously optimize the heat energy recovery efficiency;

temperature and pressure control system upgrades: the temperature and pressure control precision is improved by adopting a more advanced control strategy (such as fuzzy logic control and neural network control) to replace or assist the PID controller; the sensitivity and the reliability of an overrun alarm and protection mechanism are enhanced, and the safety and the stability of the spheroidization process are ensured;

And (3) accurately controlling mass flow and material proportion: the mass flowmeter is calibrated regularly, so that measurement accuracy is ensured; the control algorithm of the PLC or DCS system is optimized, the response speed and the adjustment precision to the material feeding speed are improved, the consistency of the product quality is ensured, and the downstream application requirements are met.

Claims

1. The utility model provides a silicon micropowder makes and uses balling furnace based on from preheating-type heat cyclic utilization, includes material powder storage bin (1), through unloading pipe (2), balling furnace body (3) and exhaust pipe (10), exhaust pipe (10) head end runs through to inside balling furnace body (3) and is fixed with balling furnace body (3), through unloading pipe (2) run through and fix at exhaust pipe (10) head end, material powder storage bin (1) connect in through unloading pipe (2) upper end, material powder storage bin (1) middle part is equipped with transition chamber (12), its characterized in that:

the lower end of the straight-through blanking pipe (2) is connected with a spiral blanking pipe (13) communicated with the straight-through blanking pipe, the spiral blanking pipe (13) is positioned in the head end of the smoke exhaust pipe (10), and the tail end of the spiral blanking pipe (13) extends out of the head end of the smoke exhaust pipe (10);

The inner middle end of the smoke exhaust pipe (10) is fixedly provided with a spiral channel (15), the center of the spiral channel (15) is fixedly provided with a communicating copper pipe (14), the lower part of the middle end of the smoke exhaust pipe (10) and the two ends of the communicating copper pipe (14) respectively penetrate and are fixedly provided with a cold air pipeline II (9) and a hot air pipeline (11), and the two ends of the communicating copper pipe (14) are respectively communicated with the head ends of the cold air pipeline II (9) and the hot air pipeline (11).

2. The spheroidizing furnace for manufacturing the silicon micro powder based on self-preheating heat recycling according to claim 1, wherein the spheroidizing furnace is characterized in that: the smoke exhaust pipe (10) is a circular pipeline, and the outer wall of the spiral channel (15) is seamlessly fixed with the inner wall of the smoke exhaust pipe (10).

3. The spheroidizing furnace for manufacturing the silicon micro powder based on self-preheating heat recycling according to claim 1, wherein the spheroidizing furnace is characterized in that: the spheroidizing furnace body (3) is provided with a spray gun assembly, the output end of the spray gun assembly is positioned inside the spheroidizing furnace body (3), the input end of the spray gun assembly is positioned outside the spheroidizing furnace body (3), and the spray gun assembly is provided with four groups in an annular distance by taking the geometric center of the horizontal section of the spheroidizing furnace body (3) as the circle center; the spray gun assembly comprises an oxygen pipe (4) and a combustible gas pipeline (5), the combustible gas pipeline (5) is communicated with the spheroidizing furnace body (3), and the oxygen pipe (4) is sleeved on the combustible gas pipeline (5) and is communicated with the spheroidizing furnace body (3); one end of the oxygen pipe (4) is communicated with the tail end of the hot air pipeline (11); one side of the spheroidizing furnace body (3) and be located transition chamber (12) below and install cold air pipeline one (8), one end of cold air pipeline one (8) is located spheroidizing furnace body (3) inside, the other end intercommunication of cold air pipeline one (8) has air duct (7), cold air pipeline two (9) end and air duct (7) surface connection and communicate with each other, air duct (7) other end is connected with air-blower (6).

4. The spheroidizing furnace for manufacturing the silicon micro powder based on self-preheating heat recycling according to claim 1, wherein the spheroidizing furnace is characterized in that: the direct discharging pipe (2) and the spiral discharging pipe (13) are of an integrated structure, graphene heat conduction layers are arranged on the outer walls of the direct discharging pipe (2) and the spiral discharging pipe (13), and graphene heat conduction layers are arranged on the outer walls of the communicating copper pipes (14).

5. The spheroidizing furnace for manufacturing the silicon micropowder based on self-preheating type heat recycling according to claim 1, wherein the parameter configuration method of the spheroidizing furnace comprises the following steps:

Combustion-supporting mixed gas ratio: calculating an optimal oxygen/fuel ratio by a chemical kinetics model; oxygen and combustible gas are respectively fed into an oxygen pipe (4) and a combustible gas pipeline (5), so that the mixed gas reaches a set oxygen/fuel ratio;

And (3) controlling the air quantity and the pressure of the blower: calculating the required blast volume and pressure by using Bernoulli equation according to the flow rates of the oxygen pipe (4) and the combustible gas pipeline (5); starting a blower (6), adjusting the rotating speed of the blower to provide matched air quantity and pressure, and ensuring that combustion air and combustible gas are uniformly mixed and smoothly ignited in the spray gun assembly;

Setting parameters of a spiral blanking pipe: calculating the preheating time required by the silica powder in a preset temperature range, and determining the pitch and the length of the spiral blanking pipe (13) by combining the relation between the pitch and the linear speed;

And (3) building a temperature and pressure control system: installing a temperature and pressure sensor, monitoring the internal state of the spheroidizing furnace body (3) in real time, and setting the upper limit and the lower limit of the temperature and the pressure according to the thermodynamic requirement of the spheroidizing process; adopting a PID controller to dynamically adjust parameters of oxygen, combustible gas supply and blast volume according to the deviation of the actual measurement value and the set value, and setting an overrun alarm and protection mechanism;

Mass flow control and material proportioning: installing a mass flowmeter at a feed inlet, and measuring the mass flow of each material; and through a PLC or DCS system, the feeding speed of each material is automatically adjusted according to a preset formula proportion.

6. The spheroidizing furnace for manufacturing the silicon micropowder based on self-preheating heat recycling according to claim 1, wherein the mixed gas is ensured to reach a set oxygen/fuel ratio, specifically: obtaining the optimal oxygen/fuel ratio of the specific combustible gas by using a Levensfiel method, an empirical formula or an experiment, and setting the optimal oxygen/fuel ratio as a target value of a control system; the actual proportion of the mixed gas is monitored in real time, and the supply amount of oxygen and combustible gas is regulated in real time, wherein the regulation index is that the oxygen/fuel ratio is ensured to be the same as or close to the set target value.

7. The spheroidizing furnace for manufacturing the silicon micropowder based on self-preheating type heat recycling according to claim 5, wherein the preheating time required by the silicon micropowder in a preset temperature range is calculated, and the pitch and the length of a spiral blanking pipe (13) are determined by combining the relation between the pitch and the linear speed, and the spheroidizing furnace is characterized in that: the relation between the screw pitch and the linear speed is v=pi Dn/60, wherein v is the linear speed, D is the inner diameter of the spiral blanking pipe, n is the rotating speed of the spiral blanking pipe, the spiral blanking pipe (13) is simulated through fluid mechanics simulation software, the screw pitch and the length of the spiral blanking pipe (13) are optimized according to simulation results, and the optimized evaluation index is that the proper and uniform heat of the silicon micro powder is ensured to be obtained in a preheating stage, the energy consumption required by subsequent melting is reduced, and meanwhile, overheating is avoided.