Silicon powder preheating atomizer for synthesizing silicon nitride micro powder by using crystal silicon slice waste mortar

Abstract

The invention discloses a silicon powder preheating atomizer for synthesizing silicon nitride micro powder by using crystal silicon slice waste mortar. The silicon powder preheating atomizer consists of a heat preservation cavity, a silicon powder tank, an atomization emitter and a vector sealing seat, the heat preservation cavity is formed by processing hollow ball castable, is covered with a stainless steel sheet double-barrel cavity and a heat preservation cover, is internally provided with a high-temperature nitrogen pipeline system, consists of related pipelines, valves and instruments, and is used as a heat source and power for preheating, fluidizing, atomizing and conveying silicon powder in the silicon powder tank; the operation control panel is provided with related switches, buttons, a digital display meter and a pressure meter and is used for completing silicon nitrogen preheating, fluidization, metering and atomization control operation; the barrel body of the silicon powder tank is made of stainless steel, a ring foot is of a hollow frustum structure, so that sealing with a fluidization sealing disc is facilitated, a microporous ceramic filter plate is used as a tank bottom, and a tank opening is sealed by a stainless steel gland lined with an expanded graphite sealing ring; the atomization emitter is composed of a Venturi ejector, a pressure gauge, a sealing cover and a feeding pipe, and is used for sucking, mixing, atomizing, conveying and emitting fluidized and preheated silicon powder; the vector sealing seat is composed of a fluidization sealing disc and a vector scale and is used for fluidization nitrogen distribution and silicon powder sending metering.

Description

Technical Field

[0001] The invention relates to a silicon powder preheating atomizer for synthesizing silicon nitride micropowder by using waste mortar of crystalline silicon slices, and belongs to the field of comprehensive utilization of photovoltaic crystalline silicon slice waste and silicon nitride powder production equipment. Background Art

[0002] Silicon nitride is an advanced engineering ceramic material with high room temperature and high temperature strength, high hardness, abrasion resistance, oxidation resistance, and good resistance to thermal shock and mechanical shock. It is considered by the materials science community to be a new material with excellent comprehensive performance in the field of structural ceramics and the most promising alternative to nickel-based alloys for wide application in high-tech and high-temperature fields.

[0003] The synthesis process of silicon nitride powder is generally:

[0004] Silicon powder direct nitridation 3Si(s)+2N2(g)=Si3N4(s)

[0005] Silicylimine gas phase reaction 3SiCl4(g)+4NH3(g)=Si3N4(s)+12HCl(g)

[0006] Carbon thermal reduction nitridation 3SiO2(s)+6C(s)+2N2(g)=Si3N4(s)+6CO(g)

[0007] Among them, direct nitridation of silicon powder is the earliest developed process for preparing silicon nitride powder and is also the most widely used method at present. This method is to load the raw silicon powder into a sagger and place it in a reaction furnace. First, the gas in the furnace is replaced, nitrogen is introduced to heat it, and argon is added to control the reaction rate to prevent the silicon powder from reacting rapidly and overheating to melt and form balls, causing the reaction to terminate. Until the silicon powder no longer absorbs nitrogen, the furnace is stopped to cool down and the furnace is taken out. The production cycle of a single furnace is about one week, and the output is 80-200kg / furnace. The product is in granular form and must undergo subsequent processing to obtain silicon nitride powder material. It is an intermittent production process with a long reaction cycle, high energy consumption, and poor quality reliability.

[0008] Since 2006, the applicant has been concerned about the treatment of waste mortar from the processing of crystalline silicon for photovoltaic cells. On April 22, 2011, an invention patent application for "New Method for Comprehensive Treatment of Waste Mortar from Crystalline Silicon Processing of Photovoltaic Cells" with application number 201110101064.7 was filed. On August 12, 2011, an invention patent application for "Comprehensive Treatment Technology of Waste Mortar from Photovoltaic Crystalline Silicon Processing" with application number 201110238197.9 was filed; on June 26, 2012, an invention patent application for "Comprehensive Treatment Technology of Waste Mortar from Crystalline Silicon Processing without Sewage and Solid Waste Discharge" with application number 201210207989.4 was filed with the priority of the application number 201110238197.9 "Comprehensive Treatment Technology of Waste Mortar from Photovoltaic Crystalline Silicon Processing", and the patent right was obtained on May 20, 2015. On January 23, 2013, a patent application for "Unit for Recycling Silicon Powder from Waste Mortar of Crystalline Silicon Processing to Prepare Silicon Nitride Products" with application number 201310024134.2 was filed, and the patent right was obtained on November 19, 2014. On January 23, 2013, a patent application for "Entrained Flow Reactor for Recycling Silicon Powder from Waste Mortar of Crystalline Silicon Processing to Prepare Silicon Nitride Powder" with application number 201310024132.3 was filed, and the patent right was obtained on November 19, 2014.

[0009] When the above patent applications were initially filed, the multi-wire cutting process was commonly used in the field of photovoltaic crystalline silicon slicing. The waste mortar generated during the crystalline silicon slicing process was a mixed slurry of four systems: silicon material chips - Si, cutting wire abrasion debris - Fe, ineffective abrasives - SiC, and cutting fluid - polyethylene glycol; now, solar photovoltaic crystalline silicon slicing has been completely replaced by the new diamond wire cutting process, and the waste mortar generated during the crystalline silicon slicing process has become a mixed slurry of three systems: silicon material chips - Si, coolant high-purity water, and trace diamond debris. After dehydration and drying, high-purity ultrafine silicon powder with a particle size of 0 - 8um and a silicon content of more than 99.5% can be obtained, which is used as a raw material for producing silicon nitride powder. However, this silicon powder is too fine to produce silicon nitride by traditional nitriding processes. The key to solving this problem is to effectively preheat and atomize reaction raw materials such as silicon powder and nitrogen to create conditions for the rapid reaction of silicon and nitrogen to form silicon nitride. Summary of the Invention

[0010] The object of the present invention is to eliminate the defects of the original patented technology and solve the problems of effective fluidization, preheating, and atomizing transportation of silicon powder when using the by-product silicon powder from cutting crystalline silicon wafers with diamond wire as the raw material for synthesizing silicon nitride micropowder.

[0011] The object of the present invention is achieved as follows: The silicon powder preheating atomizer consists of a heat preservation cavity (1), a silicon powder tank (2), an atomization emitter (3), and a vector fluidization seat (4); among them, the heat preservation cavity (1) is processed and formed by using rock wool or hollow sphere castable, with an outer cover of a stainless steel thin plate double-barrel cavity (1.1) and a heat preservation cover (1.2), and is internally provided with a high-temperature nitrogen pipeline system (1.3), which is composed of relevant pipelines, valves, and instruments, serving as the heat source and power for preheating, fluidizing, atomizing, and transporting the silicon powder in the silicon powder tank; the operation control panel (1.4) is provided with relevant switches, buttons, digital display meters, and pressure gauges for completing the operations of silicon nitride preheating, fluidization, metering, and atomization control; the cylinder body (2.1) of the silicon powder tank (2) is made of stainless steel, with a hollow frustum structure at the foot ring, and the inner ring is made of polished abrasive material to facilitate sealing with the fluidization sealing disc (4.1). Above the foot ring, a microporous ceramic filter plate (2.2) is fixedly installed as the tank bottom, and the tank mouth is sealed with a stainless steel gland (2.3) lined with an expanded graphite sealing ring (2.4) for filling and transporting the ultra-fine high-purity silicon powder prepared from the waste mortar treatment section of crystalline silicon wafer slicing; the atomization emitter (3) consists of a Venturi ejector (3.1), a pressure gauge (3.2), a sealing cover (3.3), and a feeding pipe (3.4) for sucking, mixing, atomizing, and transporting and emitting the fluidized and preheated silicon powder; the sealing weigher (4) consists of a fluidization sealing disc (4.1) made of heat-resistant ceramic material with a polished outer circle of a cylindrical frustum and a vector scale (4.2); the silicon powder preheating atomizer is provided with process ports such as the center holes A1 and A2 of the fluidization sealing disc, the main pipe interface B0 for preheating nitrogen, the distribution pipeline interfaces B1, B2, B3, and B4, the fluidized silicon powder suction ports C1 and C2, and the (Si + N2) atomized fluid outlets D1 and D2; through the instruments, switches, and knobs on the operation control panel (1.4), the silicon powder and high-temperature nitrogen are fully mixed, heat-exchanged and preheated, fluidized, atomized, and transported, creating the most basic conditions for the production of silicon nitride micro-powder by synthesizing crystalline silicon wafer slicing waste mortar; the working steps of the silicon powder preheating atomizer are as follows: (1) Fill the qualified ultra-fine high-purity silicon powder prepared from crystalline silicon wafer slicing waste mortar into the silicon powder tank (2) under nitrogen protection according to the standard of 1 / 2 - 2 / 3 of the volume of the silicon powder tank, weigh it, and seal it for standby; (2) Place the loaded silicon powder tank (2) on the fluidization sealing disc (4.1) of the vector fluidization seat (4) on the left side of the heat preservation double-barrel cavity (1.1), remove the gland (2.3), replace it with the atomization emitter 3, tighten the sealing cover (3.3), and cover the heat preservation cover (1.2); (3) Connect the preheating nitrogen to the main pipe interface B0. When the main pipe pressure and temperature reach the process requirements (0.01 - 1.0 MPa, 500 - 700 °C), turn on the N1 switch on the operation control panel (1.4). The preheating nitrogen enters the closed space formed by the sealing contact between the bottom foot ring of the silicon powder tank (2) and the fluidization sealing disc (4.1) at B1, and evenly passes through the microporous ceramic filter plate (2.2) Heat the silicon powder tank to enter the gaps between silicon powder particles, causing the silicon powder to enter a fluidized state; (IV). When the pressure difference between the pressure gauge (3.2) on the atomizing emitter (3) and the pressure gauge (Y1) of the fluidizing nitrogen is between 0.005 - 0.020 MPa, start the N3 switch to allow the preheated high-temperature nitrogen to enter the Venturi injector (3.1) of the atomizing emitter (3). With the Venturi effect, a local negative pressure is formed in the injector to suck the fluidized silicon powder in the silicon powder tank into the feeding pipe and enter the Venturi injector, forming a fully mixed (Si + N2) atomized fluid, which is sprayed into the atomizing reaction furnace chamber through the pipe connecting the outlet D1 of the atomizing emitter and the feeding port of the atomizing synthesizer to react and synthesize silicon nitride micropowder; (V). When 1 / 2 - 2 / 3 of the silicon powder in the silicon powder tank is output, place the loaded silicon powder tank on the fluidization sealing disc (4.1) of the vector fluidization seat (4) on the right side of the heat-insulating double-barrel cavity (1.1), remove the gland (2.3), replace it with the atomizing emitter 3, tighten the sealing cover (3.3), and cover the heat-insulating cover (1.2) for standby; (VI). When the remaining silicon powder in the left silicon powder tank is lower than the output flow for 15 minutes, open the N2 switch on the operation control panel (1.4). The preheated nitrogen enters the sealed space formed by the contact between the bottom ring of the silicon powder tank (2) and the fluidization sealing disc, uniformly passes through the microporous ceramic filter plate (2.2) at the bottom of the silicon powder tank to heat the silicon powder in the tank and enter the gaps between silicon powder particles, causing the silicon powder to enter a fluidized state; (VII). When the pressure difference between the pressure gauge (3.2) on the atomizing emitter (3) and the pressure gauge (Y2) of the fluidizing nitrogen is between 0.005 - 0.010 MPa and all the silicon powder in the left fluidized material tank is output, close the N1 and N3 switches to stop the left fluidization atomizing system, open the N4 switch to start the right fluidization atomizing system, allow the high-temperature nitrogen to enter the Venturi injector (3.1) of the atomizing emitter (3). With the Venturi effect, a local negative pressure is formed in the injector to suck the fluidized silicon powder in the silicon powder tank into the feeding pipe and enter the Venturi injector, forming a fully mixed (Si + N2) atomized fluid, which is sprayed into the atomizing reaction furnace chamber through the pipe connecting the outlet D2 of the atomizing emitter and the feeding port of the atomizing synthesizer to react and synthesize silicon nitride micropowder; (VIII). After the right fluidization atomizing system operates normally, remove the heat-insulating cover on the left silicon powder tank, then remove the atomizing emitter (3), take out the empty silicon powder tank, and repeat procedures (I) to (VIII) to achieve continuous cyclic operation of atomizing feeding.

[0012] The silicon powder preheating atomizer consists of a heat-insulating cavity (1), a silicon powder tank (2), an atomizing emitter (3), and a vector fluidization seat (4).

[0013] The heat preservation cavity (1) of the silicon powder preheating atomizer is formed by processing rock wool or hollow sphere castable, and is composed of a double-barrel cavity (1.1) made of stainless steel thin plate and a heat preservation cover (1.2). It is equipped with a high-temperature nitrogen pipeline system (1.3), which is composed of relevant pipelines, valves and instruments, and serves as the heat source and power for the preheating, fluidization, atomization and transportation of silicon powder in the silicon powder tank. The operation control panel (1.4) is provided with relevant switches, buttons, digital display meters and pressure gauges for completing the operations of silicon nitride preheating, fluidization, metering and atomization control.

[0014] The cylinder body (2.1) of the silicon powder tank (2) of the silicon powder preheating atomizer is made of stainless steel, with a ring-foot hollow frustum structure. The inner ring is made of polished material for grinding, which is convenient for sealing with the fluidization sealing disc (4.1). Above the ring foot, a microporous ceramic filter plate (2.2) is fixedly installed as the tank bottom, and the tank mouth is sealed with a stainless steel gland (2.3) lined with an expanded graphite sealing ring (2.4) for filling and transporting the ultra-fine high-purity silicon powder prepared from the waste mortar treatment section of crystalline silicon slicing.

[0015] The atomization emitter (3) of the silicon powder preheating atomizer is composed of a Venturi injector (3.1), a pressure gauge (3.2), a sealing cover (3.3) and a feeding pipe (3.4), and is used to complete the suction, mixing, atomization and transportation and emission of the silicon powder after fluidization preheating.

[0016] The vector fluidization seat (4) of the silicon powder preheating atomizer is composed of a fluidization sealing disc (4.1) made of heat-resistant ceramic material with a polished outer circle of a cylindrical frustum and a vector scale (4.2), and is used to complete the storage of preheated fluidization nitrogen and the metering of the sending amount of silicon powder in the fluidized material tank.

[0017] The present powder will be further described in conjunction with the attached drawings and embodiments. Description of the Drawings

[0018] Figure 1 It is a structural diagram of a silicon powder preheating atomizer (hereinafter referred to as silicon powder preheating atomizer) for synthesizing silicon nitride micro-powder from waste mortar of crystalline silicon slices.

[0019] Figure 2 It is a top view of the silicon powder preheating atomizer.

[0020] Figure 3 It is a front view of the silicon powder preheating atomizer.

[0021] Figure 4 It is a cross-sectional view of the heat preservation cavity of the silicon powder preheating atomizer.

[0022] Figure 5 It is a diagram of the silicon powder tank of the silicon powder preheating atomizer.

[0023] Figure 6 It is a diagram of the lid of the silicon powder tank of the silicon powder preheating atomizer.

[0024] Figure 7 It is a diagram of the atomizing emitter of the silicon powder preheating atomizer.

[0025] Figure 8 It is a cross-sectional view of the vector seal seat of the silicon powder preheating atomizer.

[0026] Figure 9 It is a top view of the vector seal seat of the silicon powder preheating atomizer.

[0027] The numbers in the figure represent the structure of the silicon powder preheating atomizer: 1 - heat preservation cavity, 2 - silicon powder tank, 3 - atomizing emitter, 4 - vector fluidization seat; 1.1 - double-barrel heat preservation sleeve, 1.2 - heat preservation cover, 1.3 - high-temperature nitrogen pipeline system, composed of relevant pipelines, valves, and instruments, 1.4 - operation control panel, realizing the control operations of silicon-nitrogen preheating, fluidization, metering, and atomization through relevant switches, buttons, digital display meters, and pressure gauges; 2.1 - silicon powder tank cylinder body, made of stainless steel, 2.2 - microporous ceramic filter plate, 2.3 - stainless steel gland, 2.4 - flexible graphite sealing ring; 3.1 - Venturi injector, 3.2 - pressure gauge, 3.3 - sealing cover, 3.4 - feeding pipe; 4.1 - fluidization seal plate, made of silicon carbide polishing disc, 4.2 - vector scale.

[0028] The letters in the figure represent the process hole numbers: A - central hole of the fluidization seal plate, B - nitrogen pipeline interface, where B1 and B2 are the silicon powder fluidization nitrogen interfaces, B3 and B4 are the atomization and transportation nitrogen interfaces, C - fluidized silicon powder suction port, D - (Si + N2) atomized fluid outlet.

[0029] The meanings of the letters and numbers on the operation control panel 1.4 in the figure are as follows: Y - nitrogen pressure gauge (range 0 - 1.6 MPa), Y0 - main pipe pressure gauge, Y1 - fluidization nitrogen pressure gauge for tank No. 1, Y2 - fluidization nitrogen pressure gauge for tank No. 2, Y3 - atomization nitrogen pressure gauge for tank No. 1, Y4 - atomization nitrogen pressure gauge for tank No. 2; the control knob N is the nitrogen valve switch, N0 - nitrogen main valve switch, N1 - fluidization nitrogen switch for tank No. 1, N2 - fluidization nitrogen switch for tank No. 2, N3 - atomization nitrogen switch for tank No. 1, N4 - atomization nitrogen switch for tank No. 2; the Chinese character "zeroing" - the weight is zeroed after installing a new cartridge, "weighing" - starting to measure the weight change of the cartridge after metering and atomization transportation, the two rows of numbers in the lower left and lower right rectangular boxes, the upper row represents the silicon powder transportation flow rate per unit time (g / s), the lower row represents the cumulative silicon powder transportation volume, and the number in the rectangular box directly above in the middle is the measured temperature of the preheating nitrogen. Detailed implementation manners

[0030] The following are specific embodiments of the present invention, but the method of the present invention is not completely limited thereto, and those skilled in the art can change or adjust the structure therein as needed.

[0031] Embodiment 1:

[0032] Such as Figure 1 is the structural diagram of the silicon powder preheating atomizer,[[]] Figure 2 is the top view of the silicon powder preheating atomizer,[[]] Figure 3 is the front view of the silicon powder preheating atomizer,[[]] Figure 4 is the sectional view of the heat preservation cavity of the silicon powder preheating atomizer,[[]] Figure 5 is the diagram of the silicon powder tank of the silicon powder preheating atomizer,[[]] Figure 6 is the diagram of the lid of the silicon powder tank of the silicon powder preheating atomizer,[[]] Figure 7 is the diagram of the atomizing emitter of the silicon powder preheating atomizer,[[]] Figure 8 is the sectional view of the vector seal seat of the silicon powder preheating atomizer,[[]] Figure 9 is shown in nine drawings such as the top view of the vector seal seat of the silicon powder preheating atomizer:

[0033] The silicon powder preheating atomizer consists of a heat preservation cavity (1), a silicon powder tank (2), an atomization emitter (3), and a vector fluidization seat (4); among them, the heat preservation cavity (1) is processed and formed with rock wool or hollow sphere castable, covered with a stainless steel thin plate double-barrel cavity (1.1) and a heat preservation cover (1.2), and is equipped with a high-temperature nitrogen pipeline system (1.3) composed of relevant pipelines, valves, and instruments, serving as the heat source and power for preheating, fluidizing, atomizing, and transporting the silicon powder in the silicon powder tank; the operation control panel (1.4) is provided with relevant switches, buttons, digital display meters, and pressure gauges for completing the operations of silicon-nitrogen preheating, fluidization, metering, and atomization control; the cylinder body (2.1) of the silicon powder tank (2) is made of stainless steel, with a ring foot hollow frustum structure, and the inner ring is made of polished abrasive material to facilitate sealing with the fluidization sealing disc (4.1). Above the ring foot, a microporous ceramic filter plate (2.2) is fixedly installed as the bottom of the tank, and the tank mouth is sealed with a stainless steel gland (2.3) lined with an expanded graphite sealing ring (2.4) for filling and transporting the ultra-fine high-purity silicon powder prepared from the waste mortar treatment section of crystalline silicon wafer slicing; the atomization emitter (3) consists of a Venturi injector (3.1), a pressure gauge (3.2), a sealing cover (3.3), and a feeding pipe (3.4) for sucking, mixing, atomizing, and transporting and emitting the fluidized and preheated silicon powder; the sealing weigher (4) consists of a fluidization sealing disc (4.1) made of heat-resistant ceramic material with a polished outer circle of a cylindrical frustum and a vector scale (4.2); the silicon powder preheating atomizer is provided with process ports such as the central holes A1 and A2 of the fluidization sealing disc, the main pipe interface B0 of the preheated nitrogen, the distribution pipeline interfaces B1, B2, B3, and B4, the fluidized silicon powder suction ports C1 and C2, and the (Si + N2) atomized fluid outlets D1 and D2; through the instruments, switches, and knobs on the operation control panel (1.4), the silicon powder and high-temperature nitrogen are fully mixed, heat-exchanged and preheated, fluidized, atomized, and transported, creating the most basic conditions for the production of silicon nitride micropowder by synthesizing waste mortar from crystalline silicon wafer slicing; the working steps of the silicon powder preheating atomizer are as follows: (1). Fill the qualified ultra-fine high-purity silicon powder prepared from crystalline silicon wafer slicing waste mortar into the silicon powder tank (2) under nitrogen protection according to the standard of 1 / 2 - 2 / 3 of the volume of the silicon powder tank, weigh it, and seal it for standby; (2). Place the loaded silicon powder tank (2) on the fluidization sealing disc (4.1) of the vector fluidization seat (4) on the left side of the heat preservation double-barrel cavity (1.1), remove the gland (2.3), replace it with the atomization emitter 3, tighten the sealing cover (3.3), and cover the heat preservation cover (1.2); (3). Connect the preheated nitrogen to the main pipe interface B0. When the main pipe pressure and temperature reach the process requirements (0.01 - 1.0 MPa, 500 - 700 °C), turn on the N1 switch on the operation control panel (1.4). The preheated nitrogen enters the closed space formed by the sealing contact between the bottom ring foot of the silicon powder tank (2) and the fluidization sealing disc (4.1), uniformly passes through the microporous ceramic filter plate (2.2) at the bottom of the silicon powder tank to heat the silicon powder particles in the silicon powder tank, and makes the silicon powder enter the fluidized state; (4). When the pressure gauge (3.2) When the pressure difference between the pressure gauge (Y1) of the fluidized nitrogen and the pressure gauge of the atomizing emitter is between 0.005 - 0.020 MPa, start the N3 switch to allow the preheated high-temperature nitrogen to enter the Venturi injector (3.1) of the atomizing emitter (3). With the Venturi effect, a local negative pressure is formed in the injector, sucking the fluidized silicon powder in the silicon powder tank into the feeding pipe and then into the Venturi injector, forming a well-mixed (Si + N2) atomized fluid. This atomized fluid is sprayed into the atomizing reaction furnace chamber through the pipe connecting the outlet D1 of the atomizing emitter and the feeding port of the atomizing synthesizer to react and synthesize silicon nitride micropowder; (V). When 1 / 2 - 2 / 3 of the silicon powder in the silicon powder tank is output, place the loaded silicon powder tank on the fluidization sealing plate (4.1) of the vector fluidization seat (4) on the right side of the heat-insulating double-barrel cavity (1.1). Remove the gland (2.3), replace it with the atomizing emitter 3, tighten the sealing cover (3.3), and cover the heat-insulating cover (1.2) for standby; (VI). When the remaining silicon powder in the left silicon powder tank is lower than the output flow for 15 minutes, open the N2 switch on the operation control panel (1.4). The preheated nitrogen enters the sealed space formed by the contact between the bottom ring of the silicon powder tank (2) and the fluidization sealing plate at B2, evenly passes through the microporous ceramic filter plate (2.2) at the bottom of the silicon powder tank to heat the silicon powder in the tank and enters the gaps between the silicon powder particles, making the silicon powder enter the fluidized state; (VII). When the pressure difference between the pressure gauge (3.2) on the atomizing emitter (3) and the pressure gauge (Y2) of the fluidized nitrogen is between 0.005 - 0.010 MPa and all the silicon powder in the left fluidized material tank is output, close the N1 and N3 switches to stop the left fluidization atomizing system. Open the N4 switch to start the right fluidization atomizing system, allowing the high-temperature nitrogen to enter the Venturi injector (3.1) of the atomizing emitter (3). With the Venturi effect, a local negative pressure is formed in the injector, sucking the fluidized silicon powder in the silicon powder tank into the feeding pipe and then into the Venturi injector, forming a well-mixed (Si + N2) atomized fluid. This atomized fluid is sprayed into the atomizing reaction furnace chamber through the pipe connecting the outlet D2 of the atomizing emitter and the feeding port of the atomizing synthesizer to react and synthesize silicon nitride micropowder; (VIII). After the right fluidization atomizing system operates normally, remove the heat-insulating cover on the left silicon powder tank, then remove the atomizing emitter (3), take out the empty silicon powder tank, and repeat procedures (I) to (VIII) to achieve continuous cyclic operation of atomizing feeding.

[0034] The silicon powder preheating atomizer consists of a heat-insulating cavity (1), a silicon powder tank (2), an atomizing emitter (3), and a vector fluidization seat (4).

[0035] The heat preservation cavity (1) of the silicon powder preheating atomizer is formed by processing rock wool or hollow sphere castable, and is composed of a double-barrel cavity (1.1) and a heat preservation cover (1.2) made of stainless steel thin plates. It is internally provided with a high-temperature nitrogen pipeline system (1.3), which is composed of relevant pipelines, valves, and instruments, serving as the heat source and power for the preheating, fluidization, atomization, and transportation of silicon powder in the silicon powder tank; the operation control panel (1.4) is provided with relevant switches, buttons, digital display meters, and pressure gauges for completing the operations of silicon nitride preheating, fluidization, metering, and atomization control.

[0036] The cylinder body (2.1) of the silicon powder tank (2) of the silicon powder preheating atomizer is made of stainless steel, with a ring foot and a hollow frustum structure. The inner ring is made of abrasive polishing material to facilitate sealing with the fluidization sealing disc (4.1). Above the ring foot, a microporous ceramic filter plate (2.2) is fixedly installed as the tank bottom, and the tank mouth is sealed with a stainless steel gland (2.3) lined with an expanded graphite sealing ring (2.4) for filling and transporting the ultra-fine high-purity silicon powder prepared from the waste mortar treatment section of crystalline silicon slicing.

[0037] The atomization emitter (3) of the silicon powder preheating atomizer is composed of a Venturi injector (3.1), a pressure gauge (3.2), a sealing cover (3.3), and a feeding pipe (3.4), and is used to complete the suction, mixing, atomization, and transportation and emission of the fluidized and preheated silicon powder.

[0038] The vector fluidization seat (4) of the silicon powder preheating atomizer is composed of a fluidization sealing disc (4.1) made of heat-resistant ceramic material with a polished outer circle of a cylindrical frustum and a vector scale (4.2), and is used to complete the storage of preheated fluidization nitrogen and the metering of the sending amount of silicon powder in the fluidized material tank.

Claims

1. A silicon powder preheating atomizer for synthesizing silicon nitride micropowder from waste mortar of crystalline silicon slices, characterized in that: The silicon powder preheating atomizer consists of a heat preservation cavity (1), a silicon powder tank (2), an atomization emitter (3), and a vector fluidization base (4); among them, the heat preservation cavity (1) is processed and formed with rock wool or hollow sphere castable, covered with a stainless steel thin plate double-barrel cavity (1.1) and a heat preservation cover (1.2), and is internally provided with a high-temperature nitrogen pipeline system (1.3), which consists of relevant pipelines, valves, and instruments, serving as the heat source and power for preheating, fluidizing, atomizing, and transporting the silicon powder in the silicon powder tank; the operation control panel (1.4) is provided with relevant switches, buttons, digital display meters, and pressure gauges for completing the operations of silicon-nitrogen preheating, fluidization, metering, and atomization control; the cylinder body (2.1) of the silicon powder tank (2) is made of stainless steel plate, with a ring foot hollow frustum structure, and the inner ring is made of polished abrasive material to facilitate sealing with the fluidization sealing plate (4.1). Above the ring foot, a microporous ceramic filter plate (2.2) is fixedly installed as the tank bottom, and the tank mouth is sealed with a stainless steel gland (2.3) with an inner liner of expanded graphite sealing ring (2.4) for filling and transporting the ultra-fine high-purity silicon powder prepared from the crystalline silicon wafer waste mortar treatment section; the atomization emitter (3) consists of a Venturi ejector (3.1), a pressure gauge (3.2), a sealing cover (3.3), and a feeding pipe (3.4) for sucking, mixing, atomizing, and transporting and emitting the fluidized and preheated silicon powder; the sealing weighing device (4) consists of a fluidization sealing plate (4.1) made of heat-resistant ceramic material with a polished outer circle of a cylindrical frustum and a vector scale (4.2); the silicon powder preheating atomizer is provided with process ports such as the center holes A1 and A2 of the fluidization sealing plate, the preheating nitrogen main pipe interface B0, the distribution pipeline interfaces B1, B2, B3, B4, the fluidized silicon powder suction ports C1 and C2, and the (Si + N2) atomized fluid outlets D1 and D2; through the instruments, switches, and knobs on the operation control panel (1.4), the silicon powder and high-temperature nitrogen are fully mixed, heat-exchanged and preheated, fluidized, atomized and transported, creating the most basic conditions for the production of silicon nitride micropowder by synthesizing crystalline silicon wafer waste mortar; the working steps of the silicon powder preheating atomizer are as follows: (1). Fill the qualified ultra-fine high-purity silicon powder prepared from crystalline silicon wafer waste mortar into the silicon powder tank (2) under nitrogen protection according to the standard of 1 / 2 - 2 / 3 of the volume of the silicon powder tank, weigh it, and seal it for standby; (2). Place the loaded silicon powder tank (2) on the fluidization sealing plate (4.1) of the vector fluidization base (4) on the left side of the heat preservation double-barrel cavity (1.1), remove the gland (2.3), replace it with the atomization emitter 3, tighten the sealing cover (3.3), and cover the heat preservation cover (1.2); (3). Connect the preheating nitrogen to the main pipe interface B0. When the main pipe pressure and temperature reach the process requirements (0.01 - 1.0 MPa, 500 - 700 °C), turn on the N1 switch on the operation control panel (1.4). The preheating nitrogen enters the closed space formed by the sealing contact between the bottom ring foot of the silicon powder tank (2) and the fluidization sealing plate (4.1), uniformly passes through the microporous ceramic filter plate (2.2) at the bottom of the silicon powder tank to heat the silicon powder particles in the silicon powder tank, and makes the silicon powder enter the fluidized state; (4). When the pressure gauge (3.2) When the pressure difference between the pressure gauge (Y1) of the fluidized nitrogen and the pressure gauge of the atomizing emitter is between 0.005 - 0.020 MPa, start the N3 switch to allow the preheated high-temperature nitrogen to enter the Venturi injector (3.1) of the atomizing emitter (3). With the Venturi effect, a local negative pressure is formed in the injector to suck the fluidized silicon powder in the silicon powder tank into the feeding pipe and enter the Venturi injector, forming a well-mixed (Si + N2) atomized fluid, which is sprayed into the atomizing reaction furnace through the pipe connecting the outlet D1 of the atomizing emitter and the feeding port of the atomizing synthesizer to react and synthesize silicon nitride micropowder; (V). When 1 / 2 - 2 / 3 of the silicon powder in the silicon powder tank is output, place the loading silicon powder tank on the fluidization sealing disc (4.1) of the right vector fluidization seat (4) of the heat-insulating double-barrel cavity (1.1), remove the gland (2.3), replace it with the atomizing emitter 3, tighten the sealing cover (3.3), and cover the heat-insulating cover (1.2) for standby; (VI). When the remaining silicon powder in the left silicon powder tank is lower than the output flow for 15 minutes, open the N2 switch on the operation control panel (1.4). The preheated nitrogen enters the closed space formed by the bottom ring of the silicon powder tank (2) in contact with the fluidization sealing disc, uniformly passes through the microporous ceramic filter plate (2.2) at the bottom of the silicon powder tank to heat the silicon powder in the tank and enter the gaps between the silicon powder particles, making the silicon powder enter the fluidized state; (VII). When the pressure difference between the pressure gauge (3.2) on the atomizing emitter (3) and the pressure gauge (Y2) of the fluidized nitrogen is between 0.005 - 0.010 MPa and all the silicon powder in the left fluidized material tank is output, close the N1 and N3 switches to stop the left fluidization atomizing system, open the N4 switch to start the right fluidization atomizing system, allow the high-temperature nitrogen to enter the Venturi injector (3.1) of the atomizing emitter (3), form a local negative pressure in the injector with the Venturi effect, suck the fluidized silicon powder in the silicon powder tank into the feeding pipe, enter the Venturi injector, form a well-mixed (Si + N2) atomized fluid, and spray it into the atomizing reaction furnace through the pipe connecting the outlet D2 of the atomizing emitter and the feeding port of the atomizing synthesizer to react and synthesize silicon nitride micropowder; (VIII). After the right fluidization atomizing system works normally, remove the heat-insulating cover on the left silicon powder tank, then remove the atomizing emitter (3), take out the empty silicon powder tank, and repeat procedures (I) to (VIII) to achieve continuous cyclic operation of atomizing feeding.

2. The silicon powder preheating atomizer for synthesizing silicon nitride micropowder from waste mortar of crystalline silicon slices according to claim 1, wherein: The silicon powder preheating atomizer consists of a heat preservation cavity (1), a silicon powder tank (2), an atomization emitter (3), and a vector fluidization seat (4).

3. The silicon powder preheating atomizer for synthesizing silicon nitride micropowder from waste mortar of crystalline silicon slices according to claim 1, characterized in that: The heat preservation cavity (1) of the silicon powder preheating atomizer is formed by processing rock wool or hollow sphere castable, and is composed of a double-barrel cavity (1.1) with a stainless steel thin plate outer cover and a heat preservation cover (1.2). It is internally provided with a high-temperature nitrogen pipeline system (1.3), which is composed of relevant pipelines, valves, and instruments, serving as the heat source and power for preheating, fluidizing, atomizing, and transporting the silicon powder in the silicon powder tank; the operation control panel (1.4) is provided with relevant switches, buttons, digital display meters, and pressure gauges for completing the operations of silicon nitride preheating, fluidization, metering, and atomization control.

4. The silicon powder preheating atomizer for synthesizing silicon nitride micropowder from waste mortar of crystalline silicon slices according to claim 1, characterized in that: The cylinder body (2.1) of the silicon powder tank (2) of the silicon powder preheating atomizer is made of stainless steel, with a ring foot and a hollow frustum structure. The inner ring is made of polished abrasive material to facilitate sealing with the fluidization sealing disc (4.1). A microporous ceramic filter plate (2.2) is fixedly installed above the ring foot as the tank bottom, and the tank mouth is sealed with a stainless steel gland (2.3) lined with an expanded graphite sealing ring (2.4) for filling and transporting the ultra-fine high-purity silicon powder prepared from the waste mortar treatment section of crystalline silicon slicing.

5. The silicon powder preheating atomizer for synthesizing silicon nitride micropowder from waste mortar of crystalline silicon slicing according to claim 1, characterized in that: The atomization emitter (3) of the silicon powder preheating atomizer is composed of a Venturi injector (3.1), a pressure gauge (3.2), a sealing cover (3.3), and a feeding pipe (3.4), and is used to complete the suction, mixing, atomization, and transportation and emission of the fluidized and preheated silicon powder.

6. The silicon powder preheating atomizer for synthesizing silicon nitride micropowder from waste mortar of crystalline silicon slicing according to claim 1, characterized in that: The vector fluidization seat (4) of the silicon powder preheating atomizer is composed of a fluidization sealing disc (4.1) made of heat-resistant ceramic material with a polished outer circle of a cylindrical frustum and a vector scale (4.2), and is used to complete the storage of preheated fluidization nitrogen and the metering of the silicon powder sending amount in the fluidized material tank.

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