Spiral screen type pulverization slag quenching furnace, solid waste and waste heat recovery low-carbon environment-friendly system and solid waste and waste heat recovery low-carbon environment-friendly method

Abstract

The invention discloses a spiral screen type pulverization slag quenching furnace and a solid waste waste heat recovery low-carbon environment-friendly system and method.The spiral screen type pulverization slag quenching furnace comprises a furnace body, and the upper portion of the furnace body is provided with a slag inlet, an insertion plate sealer and a hydraulic rotary sealer; an ash residue spiral sieve is arranged in the furnace body; sieve filtering holes are gradually reduced; the first-stage spiral ash primary screen, the first-stage spiral ash secondary screen, the second-stage spiral ash primary screen, the second-stage spiral ash secondary screen and the primary side fine screen are sequentially connected, and the third-stage spiral ash primary screen, the third-stage spiral ash secondary screen and the secondary side fine screen are fixedly connected according to the size of screen holes from small to large. The solid waste waste heat recovery low-carbon environment-friendly system comprises a spiral screen type pulverization slag quenching furnace, a calcination and thermal reduction furnace, a cyclone dust collector, a dust hydration treatment pond, a fine screening device, expansion power generation equipment, a gas-water heat exchange station and the like, and waste heat recovery gradient utilization and solid waste environment-friendly treatment of waste heat ash in Pidgeon process magnesium smelting are achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of solid waste waste heat resource recovery, and specifically relates to a spiral screen type pulverizing slag furnace, a solid waste waste heat recovery low-carbon and environmentally friendly system and method. Background Art

[0002] The Pidgeon process for magnesium smelting has become the mainstream technology for global magnesium smelting due to its lower raw material and energy consumption compared to electrolysis, simple equipment, low investment, and adaptable production scale to market demand. It is also suitable for decentralized and regional industrial development. The Pidgeon process for magnesium smelting involves crushing and calcining dolomite to produce calcined dolomite (MgO·CaO). The calcined dolomite is then mixed with auxiliary materials such as ferrosilicon powder (75% silicon) and fluorite powder (≥95% CaF2) to form pellets. Finally, the pellets are placed in a reduction tank for vacuum thermal reduction (at a vacuum of 1.33 Pa and a temperature of 1200-1250°C) to produce magnesium (Mg) and Ca2SiO4.

[0003] During the vacuum thermal reduction stage, after the pellets react at high temperature (1200-1250°C) in the reduction tank, a certain amount of thermal reduction solid phase slag (including Mg, Ca2SiO4, CaF2, and unreacted CaO, MgO, etc.) remains and is discharged from the reduction tank; secondly, during the calcination stage, after the dolomite is calcined, a small amount of undecomposed carbonate or free CaO produced by overburning and other ore impurities will remain, which will mix with the thermal reduction slag to form hot waste slag (particle size of about 20-50mm, temperature of about 800-1000°C), which needs to be cooled by water spray or naturally cooled before being stored or landfilled. However, during the cooling process, the hot waste slag will gradually pulverize, causing dust pollution and waste heat loss. At the same time, the storage and landfill of solid waste will cause a large amount of land pollution, which is very harmful to the environment.

[0004] To address the above problems, existing technical means include: (1) regulating the slag phase composition and optimizing the reduction conditions (such as temperature and ratio) to reduce the unreacted residue, but it is still impossible to fundamentally eliminate the generation of waste slag; (2) recovering the rare earth resources in the residual waste slag, but there are still waste heat resources and some waste slag that cannot be recovered; (3) using a three-phase electric furnace to melt the waste slag to produce building materials or mineral wool or using chemical means to extract gypsum or nitrogen fertilizer for utilization, but this type of technology increases energy consumption and other process inputs and is less economical. In summary, it is difficult for existing technical means to simultaneously meet the requirements of waste heat ash resource recovery and low-carbon and environmentally friendly treatment in the Pijiang process of magnesium smelting. Summary of the Invention

[0005] The present invention provides a spiral screen type pulverizing slag furnace, a solid waste waste heat recovery low-carbon environmentally friendly system and method, which realizes the waste heat recovery cascade utilization and solid waste environmentally friendly treatment of waste heat ash in the Pijiang process of magnesium smelting.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] In a first aspect, the present invention provides a spiral screen type pulverizing slag furnace, comprising a furnace body, wherein the upper portion of the furnace body is provided with a slag inlet, a plug plate closer and a hydraulic rotary closer in order from top to bottom;

[0008] The furnace body is provided with a central support guide column and an ash spiral screen fixed on the furnace body wall and the central support guide column; the inner edge of the ash spiral screen is fixedly connected to the vertical surface of the support guide column, and the outer edge is fixedly connected to the inner wall surface of the furnace body;

[0009] The furnace body is provided with a high-pressure cooling air inlet and a hot air-ash mixed flow outlet;

[0010] The ash spiral screen includes a first-level spiral ash primary screen, a first-level spiral ash secondary screen, a second-level spiral ash primary screen, a second-level spiral ash secondary screen, and a primary side fine screen, which are connected in sequence according to the sieve holes from large to small, and a third-level spiral ash primary screen, a third-level spiral ash secondary screen, and a secondary side fine screen with bottom sieve filtration, which are fixedly connected with the sieve holes from small to large.

[0011] A further improvement of the present invention is that the hydraulic rotary sealer includes a rotary shaft, a rotary sealing plate and a hydraulic actuator, the rotary shaft is rotatably connected to two rotary sealing plates, the rotary sealing plates include a lever arm type semicircular sealing plate and a sliding locking pin, the lever arm type semicircular sealing plate includes a sleeve, a semicircular sealing plate and a lever arm, and the head end of the lever arm is clamped on the rotary shaft through the sleeve;

[0012] The hydraulic actuator includes an inner bearing support seat, a flange head, a slide rail support seat, a radial hydraulic actuator cylinder, and a circumferential hydraulic actuator cylinder; the inner bearing support seat is rotatably connected to the rotating shaft, and the slide rail support seat is provided with an arc-shaped slide groove; the two ends of the slide rail support seat are fixedly connected to the inner bearing support cylinder seat by two connecting rods; the two connecting rods are equipped with a first connecting member and a second connecting member, the first connecting member is fixed with a first positioning screw, and the second connecting member is fixed with a second positioning screw; the flange head is fixed to the end of the bearing support seat;

[0013] The sliding locking pin passes through the slide groove and is fixedly connected to the end of the lever arm; the end ring of the cylinder of the radial hydraulic actuator is sleeved on the first positioning screw, the top ring of the hydraulic rod of the radial hydraulic actuator is sleeved on the middle part of the circumferential hydraulic actuator, and the end ring of the cylinder of the circumferential hydraulic actuator is sleeved on the second positioning screw, and the top ring of the hydraulic rod of the circumferential hydraulic actuator and the top ring of the hydraulic rod are both concentrically sleeved with the sliding locking pin.

[0014] A further improvement of the present invention is that the inner channel of the slag inlet is connected to the insert plate closer, a square groove is provided in the middle of the insert plate closer, and a horizontally movable sealing plate is provided in the square groove.

[0015] A further improvement of the present invention is that: the first-level spiral ash primary screen includes a first-level spiral primary screen guide plate with a first-level spiral primary screen array hole, the first-level spiral ash secondary screen includes a first-level spiral secondary screen guide plate with a first-level spiral secondary screen array hole, the second-level spiral ash primary screen includes a second-level spiral primary screen guide plate with a second-level spiral primary screen array hole, the second-level spiral ash secondary screen includes a second-level spiral secondary screen guide plate with a second-level spiral secondary screen array hole, the third-level spiral ash primary screen includes a third-level spiral primary screen guide plate with a third-level spiral primary screen array hole, and the third-level spiral ash secondary screen includes a third-level spiral secondary screen guide plate with a third-level spiral secondary screen array hole.

[0016] A further improvement of the present invention is that: the aperture of the first-level spiral primary screen array hole is 40-50 mm, the aperture of the first-level spiral secondary screen array hole is 30-40 mm, the aperture of the second-level spiral primary screen array hole is 20-30 mm; the aperture of the second-level spiral secondary screen array hole is 15-20 mm; the aperture of the third-level spiral primary screen array hole is 5-10 mm, and the aperture of the third-level spiral secondary screen array hole is 2-5 mm; the primary side fine screen adopts a 5-mesh screen, and the secondary side fine screen adopts a 100-mesh or larger screen.

[0017] A further improvement of the present invention is that the furnace body is a vertical cylindrical tank with a wall thickness greater than 20 mm, and the outside of the furnace body is coated with an inorganic insulation body.

[0018] In a second aspect, the present invention provides a low-carbon and environmentally friendly system for recovering waste heat from solid waste, comprising a calcining and thermal reduction furnace, a waste heat ash transport plate, a high-pressure fan, a cyclone dust collector, a reclaimed water tank, a reclaimed water booster pump, a dust hydration treatment tank, an environmentally friendly building material preparation station, a fine screener, an expansion power generation device, an air-water heat exchange station, a heating station, a hot water reflux pump, and a softened water-constant pressure water supply system, as well as a spiral screen-type pulverizing slag furnace according to claim 1;

[0019] The head end of the waste heat ash transport plate is used to receive the high-temperature waste heat ash generated by the calcination and thermal reduction furnace, and the transport end of the waste heat ash transport plate is connected to the slag inlet; the inlet of the cyclone dust collector is connected to a hot air ash mixed flow outlet of the spiral screen type pulverizing slag furnace, and the outlet is connected to the inlet of the fine screener, the high-pressure fan outlet is connected to the high-pressure cooling air inlet of the spiral screen type pulverizing slag furnace, and the air outlet of the fine screener is connected to the air inlet of the calcination and thermal reduction furnace and the expansion power generation equipment through pipelines; the air outlet of the expansion power generation equipment is connected to the air side pipeline inlet of the air-water heat exchange station, and the air side pipeline outlet of the air-water heat exchange station is connected to the calcination and thermal reduction furnace;

[0020] One end of the water side of the air-water heat exchange station is connected to the heating station, and the other end is connected to the hot water reflux pump. One end of the hot water reflux pump is connected to the pipeline outlet of the heating station, and the other end is connected to the softened water-constant pressure water replenishment system; the dust hydration treatment pool is connected to the fly ash outlet of the cyclone dust collector through a cloth belt, one end of the reclaimed water booster pump is connected to the reclaimed water pool, and the other end is connected to the spray equipment of the dust hydration treatment pool by a pipeline. The environmentally friendly building materials preparation station is used to treat the mud mass obtained by hydration treatment as solid waste.

[0021] A further improvement of the present invention is that it also includes a manual shut-off valve for the heating gas circuit, an automatic regulating valve, and a bypass valve for the heating gas circuit, wherein the manual shut-off valve for the heating gas circuit and the automatic regulating valve are installed on a first pipeline, a second pipeline where the bypass valve for the heating gas circuit is located is connected in parallel with the first pipeline where the manual shut-off valve and the automatic regulating valve are located, and the third pipeline and the fourth pipeline are connected to the calcining and thermal reduction furnace and the fine screener respectively;

[0022] The manual shut-off valve and the automatic regulating valve of the power generation circuit are connected in sequence with flanges and pipelines, and the bypass valve of the power generation circuit is connected in parallel with the manual shut-off valve and the automatic regulating valve of the power generation circuit with pipelines, and are connected to the gas inlet of the expansion power generation equipment and the gas outlet of the fine screener in front and back.

[0023] In a third aspect, the present invention provides a solid waste waste heat recovery method, based on the above-mentioned solid waste waste heat recovery low-carbon and environmentally friendly system, comprising the following steps:

[0024] When the solid waste waste heat recovery low-carbon environmental protection system is started, the calcination and thermal reduction furnace has completed the dolomite calcination and thermal reduction process in the first Pijiang process magnesium smelting, and the calcined residue and thermal reduction slag are collected and mixed, and then transported to the waste hot ash conveyor loading port for unloading. The waste hot ash conveyor is lifted to the slag inlet by the waste hot ash conveyor and enters the spiral screen type pulverization slag furnace for waste heat recovery;

[0025] Before slag is fed in, the insert plate sealer and the hydraulic rotary sealer of the spiral screen type pulverizing slag furnace are both in a closed state; when the waste slag enters the bottom of the funnel type slag inlet, the insert plate sealers are opened in sequence to allow the waste slag to fall onto the rotary seal plate of the hydraulic rotary sealer, and then the insert plate sealer is closed to allow the waste slag to enter the furnace body, and then the hydraulic rotary sealer is closed;

[0026] After the waste slag enters the furnace body, the rotating sealing plate and the plug-in plate sealer are closed to put the furnace body in a closed state. At the same time, the high-pressure fan is started to send high-pressure cooling air into the furnace body. Under the combined action of gravity and high-pressure cooling air, the waste hot ash is gradually cooled and screened along the ash spiral screen. The high-pressure cold air forms a vortex along the central support guide column and the ash spiral screen in the closed space of the furnace body, fully contacting and exchanging heat with the waste hot ash, so that the waste hot ash is gradually cooled and ashed, the particle size is reduced, and the sieve falls. The fly ash and the wind form a high-temperature air-ash two-phase mixed flow of ℃, which flows from top to bottom along the ash spiral screen to the hot air-ash mixed flow outlet and enters the cyclone dust collector for air-ash separation and dust removal.

[0027] The high-temperature air-ash two-phase mixed flow is separated and dusted in the cyclone dust collector, and the fly ash is transported from the bottom of the cyclone dust collector to the dust hydration treatment pool via a cloth belt;

[0028] The reclaimed water booster pump draws reclaimed water from the reclaimed water pool into the dust reduction cooling sprayer of the dust hydration treatment pool to cool the stored high-temperature dust and form a slurry on the sedimentation plate. The slurry is then transported to the environmentally friendly building material preparation station for solid waste treatment and made into building materials such as calcium silicate boards and environmentally friendly bricks.

[0029] The high-temperature wind carries a small amount of dust into the fine screen for secondary dust removal, and then enters the expansion power generation equipment to drive the generator to generate electricity.

[0030] A further improvement of the present invention is that after the high-temperature wind has been expanded and powered by power generation equipment, it enters the gas-water heat exchange station to exchange heat with water and then cools down again. It then enters the calcination and thermal reduction furnace through a gas transport pipeline to preheat or assist in heating the materials in the calcination and thermal reduction furnace, completing the final waste heat recovery. The circulating water of the gas-water heat exchange station is produced and replenished by a softened water-constant pressure water replenishment system. The circulating water heated by heat exchange is introduced into the heating station through a hot water pipeline for use. The circulating water used in the heating station is pressurized by a hot water reflux pump and then re-enters the gas-water heat exchange station for recycling. Compared with the existing technology, the present invention has at least the following beneficial technical effects:

[0031] The spiral screen type pulverizing slag furnace provided by the present invention can effectively utilize the phenomenon that the waste hot slag is cooled and ashed layer by layer from the surface to the inner core, and uses a spiral screen to vortex the mixed two-phase flow when the air and the waste hot slag generated in the Pijiang method magnesium smelting process are directly contacted for heat exchange, thereby fully improving the contact area and heat exchange time between the air and the waste hot slag, and ensuring the recovery efficiency of the spiral screen type pulverizing slag furnace for the waste hot slag; by the cyclic opening and closing of the plug plate closer and the hydraulic rotary closer, the demand for the periodic transportation of the waste hot slag into the furnace is realized, thereby ensuring the continuity and airtightness of the spiral screen type pulverizing slag furnace and the waste heat recovery system during operation.

[0032] The low-carbon and environmentally friendly system and method for solid waste waste heat recovery provided by the present invention utilizes the hot air after waste heat recovery in a cascade manner, thereby improving economic benefits by using high-grade waste heat for power generation and low-grade waste heat for heating. Secondly, the waste slag after heat exchange cooling is melted to produce building materials or mineral wool, which further improves the economic efficiency of waste heat slag recovery.

[0033] Finally, the cooling ash separated and collected by the cyclone dust collector is cooled and dusted with reclaimed water, which ensures zero pollution in the entire process of waste heat slag recycling to the greatest extent. Ultimately, the waste heat recovery and cascade utilization of waste heat ash in the Pijiang process of magnesium smelting and the environmental protection treatment of solid waste are realized, so as to improve the circular economy of the Pijiang process of magnesium smelting, reduce energy consumption, improve the effective utilization of resources, and meet the requirements of low-carbon environmental protection and sustainable development. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 This is a schematic diagram of the structure of a spiral screen type pulverizing slag furnace;

[0035] Figure 2 This is a cross-sectional view of a spiral screen type pulverizing slag furnace;

[0036] Figure 3 This is a half-section diagram of a spiral screen type pulverizing slag furnace;

[0037] Figure 4 This is a schematic diagram of the first-stage spiral ash screening structure;

[0038] Figure 5 It is a structural diagram of a hydraulic rotary sealer;

[0039] Figure 6 Schematic diagram of the rotary sealing plate structure;

[0040] Figure 7 This is a schematic diagram of a low-carbon and environmentally friendly system for recovering waste heat from solid waste. DETAILED DESCRIPTION

[0041] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0042] In order to enable those skilled in the art to better understand the technical solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0043] It should be noted that when an element is referred to as being "disposed on" another element, it may be directly on the other element or there may be another element centered thereon. When an element is considered to be "connected" to another element, it may be directly connected to the other element or there may be another element centered thereon at the same time. The terms "upper", "lower", "front", "back", "left", "right", "top", "bottom", "inside", "outside", etc. used herein indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0044] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this invention pertains. The terms used herein in the specification of the present invention are for the purpose of describing specific embodiments only and are not intended to limit the present invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0045] Example 1

[0046] Reference Figures 1 to 4 An environmentally friendly spiral screen type pulverizing slag furnace includes a furnace body 2-1-100, a funnel-type slag inlet 2-1-200, a plug-in plate closer 2-1-300, a hydraulic rotary closer 2-1-400, a high-pressure cooling air inlet 2-1-500 and a hot air-ash mixed flow outlet 2-1-600; the furnace body 2-1-100 is a vertical cylindrical tank with a wall thickness of more than 20 mm, and the metal furnace body is coated with an inorganic insulation body to achieve the effect of thermal insulation.

[0047] The furnace body 2-1-100 includes a furnace body wall, a central supporting guide column 2-1-120 and an ash spiral screen 2-1-110 fixed on the furnace body wall and the central supporting guide column 2-1-120; the supporting guide column 2-1-120 adopts a hollow metal tube with a refractory coating on the outside, one end of which is welded to the bottom of the furnace body and the other end is welded with a sealing plate, and the welds are all smooth and corrosion-resistant; the inner curved edge of the ash spiral screen 2-1-110 is fully welded to the vertical surface of the supporting guide column 2-1-120, and the outer curved edge is reliably welded or fully welded to the inner wall of the furnace body, and the welds are all smooth and corrosion-resistant.

[0048] The inner channel of the funnel-type slag inlet 2-1-200 is connected to the plug-in plate closer 2-1-300; a square groove with a height of 6 to 8 mm is opened in the middle of the plug-in plate closer 2-1-300, and a sealing plate is provided in the groove; before the ash enters the funnel-type slag inlet 2-1-200, the sealing plate is in a pushed-in state and the plug-in plate closer 2-1-300 is closed; after all the ash enters the funnel-type slag inlet 2-1-200, the sealing plate is pulled out, the plug-in plate closer 2-1-300 is opened, and the ash falls into the furnace body 2-1-100; after all the ash falls in, the sealing plate is pushed in, the plug-in plate closer 2-1-300 is closed, and the next batch of ash is waited for to be fed into the funnel-type slag inlet 2-1-200;

[0049] Reference Figure 5 and Figure 6 The hydraulic rotary sealer 2-1-400 includes a rotating shaft and two half hydraulic rotary sealers rotatably connected to the rotating shaft. The half hydraulic rotary sealers include a rotating sealing plate 2-1-420 and a hydraulic actuator 2-1-410 fixed to a column bearing support cylinder seat 2-1-412. The hydraulic actuators 2-1-410 of the two half hydraulic rotary sealers are arranged symmetrically around the center. The hydraulic actuator 2-1-410 includes a flange head 2-1-413 of the bearing support cylinder, a slide rail support seat 2-1-411, a radial hydraulic actuator 2-1-414, a circumferential hydraulic actuator 2-1-415, and a roller inner bearing support cylinder seat 2-1-412 for supporting the rotating shaft of the rotary sealer and integrated with the furnace wall. The roller inner bearing support cylinder seat is connected to the wall of the furnace body 2-1-100 and welded. The two ends of the rotating shaft are supported in roller inner bearings, which are fixedly sleeved in the support cylinder seat 2-1-412. Flange head 2-1-413 is welded to the end of bearing support seat 2-1-412, ensuring a tight seal between the bearing support seat and the furnace body, isolating the internal and external environments and preventing wind, rain, and dust from intruding into the gap between the furnace body and the bearing and bearing support seat. Slide rail support seat 2-1-411 is provided with a quarter-circular slot. Both ends of slide rail support seat 2-1-411 are fixedly connected to inner bearing support cylinder seat 2-1-412 via two connecting rods. A first and second connecting member are mounted on these two connecting rods. The first connecting member is secured with a first positioning screw, and the second connecting member is secured with a second positioning screw.

[0050] The rotating sealing plate 2-1-420 includes a lever arm type semicircular sealing plate 2-1-421 and a sliding locking pin 2-1-424. The lever arm type semicircular sealing plate 2-1-421 includes a sleeve, a semicircular sealing plate and a lever arm. The end of the lever arm is fixed with a sliding locking pin 2-1-424 connected by a thread. The semicircular sealing plate adopts a metal plate with a thickness of 6 to 8 mm, and an intermittent metal sleeve is welded on the straight side to be clamped on the rotating shaft. Among them, the lever arm is a thick-walled metal square tube, and the head end is welded with another metal sleeve of the same material as the semicircular sealing plate, which is clamped on the rotating shaft and installed between the outer wall of the furnace body and the bottom surface of the slide rail support seat 2-1-411, and a certain gap is retained to facilitate relative sliding.

[0051] Among them, the rotating axis and the lever-arm type semicircular sealing plate 2-1-421 of the hydraulic rotary sealer 2-1-400 are located inside the furnace body 2-1-100, and the remaining parts are located outside the furnace body 2-1-100. When the hydraulic rotary sealer 2-1-400 is in the closed state, the two semicircular sealing plates are in a horizontal state, forming a circular plate, the outer peripheral surface of which is in contact with the inner wall of the furnace body 2-1-100.

[0052] The sliding locking pin 2-1-424 serves as a sliding locator and is fixed to the end of the arm-type semicircular sealing plate 2-1-421 by threaded connection. The sliding locking pin 2-1-424 can slide in the arc-shaped sliding groove of the slide rail support seat 2-1-411; the cylinder end ring of the radial hydraulic actuator 2-1-414 is sleeved on the first positioning screw close to the flange head 2-1-413, and the top ring of the hydraulic rod of the radial hydraulic actuator 2-1-414 is sleeved on the cylinder positioning screw in the middle of the circumferential hydraulic actuator 2-1-415. The circular ring at the end of the cylinder of the radial hydraulic actuator 2-1-415 is sleeved on the second positioning screw, and the top circular ring of the hydraulic rod of the circumferential hydraulic actuator 2-1-415 is concentrically sleeved with the sliding locking pin 2-1-424. The pin rod of the sliding locking pin 2-1-424 passes through the slide groove of the slide rail support seat and sleeves the top circular ring of the hydraulic rod of the circumferential hydraulic actuator 2-1-415; the first positioning screw, the second positioning screw and the cylinder positioning screw are designed with top threads to facilitate the fixing and anti-slipping of the nut; the lower half is designed as a smooth rod, which serves as a rotating axis for circular rotation. As the hydraulic rods of the radial hydraulic actuator 2-1-414 and the circumferential hydraulic actuator 2-1-415 cooperate to extend and retract, the sliding locking pin 2-1-424 is driven to move in the slide groove, and the power arm and the semicircular sealing plate complete the opening and closing action;

[0053] Before the ash enters the furnace body 2-1-100 from the insert plate closer 2-1-300, the hydraulic rotary closer 2-1-400 is in a closed state, and the force arm type semicircular sealing plate 2-1-421 is in a horizontal state; when the ash enters the furnace body through the insert plate closer 2-1-300, the insert plate closer 2-1-300 is closed, and the high-pressure cooling air inlet 2-1-500 is opened to supply air, and the hydraulic rotary closer 2-1-400 drives the sliding locking pin 2-1-424 to move in the circular arc groove under the coordinated action of the radial hydraulic actuator 2-1-414 and the circumferential hydraulic actuator 2-1-415, and drives the power arm and the semicircular sealing plate to rotate from a horizontal state to a vertical state, and the semicircular sealing plate is fully opened, so that the ash Entering the spiral ash spiral screen 2-1-110, the air-ash contact heat exchange begins; when the ash all falls into the ash spiral screen 2-1-110 under the combined force of gravity and high-pressure cooling air, the semicircular cover is closed, waiting for the next batch of ash to enter the furnace body, so as to ensure the airtightness and working continuity of the spiral screen type pulverizing slag furnace when ash is fed; the ash falling into the ash spiral screen 2-1-110 accelerates the vortex along the spiral screen and fully contacts and exchanges heat with the high-pressure cooling air; the ash is gradually ashed from the outside to the inside due to cooling, and the fly ash and cooling air form a wind-ash mixed flow vortex flow, which continuously cools the ash and flows toward the hot air-ash mixed flow outlet 2-1-600; after the ash is gradually ashed, the particle size gradually decreases and it gradually falls along the ash spiral screen.

[0054] Reference Figure 3The ash spiral screen 2-1-110 includes a first-level spiral ash primary screen 2-1-111, a first-level spiral ash secondary screen 2-1-112, a second-level spiral ash primary screen 2-1-113, a second-level spiral ash secondary screen 2-1-114, a primary side fine screen 2-1-115, and a third-level spiral ash primary screen 2-1-117, a third-level spiral ash secondary screen 2-1-116 and a secondary side fine screen 2-1-118 for bottom screening, which are connected in sequence according to the sieve holes from large to small. The first-stage spiral ash primary screen 2-1-111 includes a first-stage spiral primary screen guide plate 2-1-111-1, and the first-stage spiral primary screen guide plate 2-1-111-1 is provided with a first-stage spiral primary screen array hole 2-1-111-2, wherein the aperture of the first-stage spiral primary screen array hole 2-1-111-2 is 40 to 50 mm; the first-stage spiral ash secondary screen 2-1-112 includes a first-stage spiral secondary screen guide plate 2-1-112-1, and the first-stage spiral secondary screen guide plate 2-1-112-1 is provided with a first-stage spiral secondary screen array hole 2-1-112-2, wherein the aperture of the first-stage spiral secondary screen array hole 2-1-112-2 is 40 to 50 mm. The aperture of the array hole 2-1-112-2 is 30 to 40 mm; the secondary spiral ash primary screen 2-1-113 includes a secondary spiral primary screen guide plate 2-1-113-1, and the secondary spiral primary screen guide plate 2-1-113-1 is provided with a secondary spiral primary screen array hole 2-1-113-2, and the aperture of the secondary spiral primary screen array hole 2-1-113-2 is 20 to 30 mm; the secondary spiral ash secondary screen 2-1-114 includes a secondary spiral secondary screen guide plate 2-1-114-1, and the secondary spiral secondary screen guide plate 2-1-114-1 is provided with a secondary spiral secondary screen array hole 2-1-113-2. The sieve array hole 2-1-114-2, the aperture of the secondary spiral secondary sieve array hole 2-1-114-2 is 15 to 20 mm; the three-stage spiral ash primary screen 2-1-117 includes a three-stage spiral primary screen guide plate 2-1-117-1, and the three-stage spiral primary screen guide plate 2-1-117-1 is provided with a three-stage spiral primary screen array hole 2-1-117-2, and the aperture of the three-stage spiral primary screen array hole 2-1-117-2 is 5 to 10 mm; the three-stage spiral ash secondary screen 2-1-116 includes a three-stage spiral secondary screen guide plate 2-1-116-1, and the three-stage spiral secondary screen guide plate 2-1-116-1 is provided with a three-stage spiral primary screen array hole 2-1-117-2, and the aperture of the three-stage spiral primary screen array hole 2-1-117-2 is 5 to 10 mm. A three-stage spiral secondary screen array hole 2-1-116-2 is provided on the flow plate 2-1-116-1. The aperture of the three-stage spiral secondary screen array hole 2-1-116-2 is 2 to 5 mm. The primary side fine screen 2-1-115 adopts a metal screen of about 5 meshes, and the secondary side fine screen 2-1-118 adopts a metal screen of more than 100 meshes. The primary side fine screen 2-1-115 is fixed at an angle of 10° to 15° to the horizontal plane, and the secondary side fine screen 2-1-118 is fixed at an angle of -10° to -15° to the horizontal plane, so as to increase the gravity flow screening effect of the ash.

[0055] Among them, the first-stage spiral primary screen guide plate 2-1-111-1, the first-stage spiral secondary screen guide plate 2-1-112-1, the second-stage spiral primary screen guide plate 2-1-113-1, the second-stage spiral secondary screen guide plate 2-1-114-1, the third-stage spiral primary screen guide plate 2-1-117-1 and the third-stage spiral secondary screen array hole 2-1-116-2 are all made of spirally bent metal plates with a thickness of 6 to 10 mm.

[0056] Example 2

[0057] Reference Figure 7 , a low-carbon and environmentally friendly system for recovering waste heat from solid waste, comprising a calcining and thermal reduction furnace 1-1, a waste heat ash transport vehicle 1-2, a waste heat ash transport plate 1-3, a spiral screen type pulverizing slag furnace 2-1, a high-pressure fan 2-2, a one-way equalizing pressure valve 2-3, a cyclone dust collector 2-4, a grey water tank 2-5, a grey water booster pump 2-6, a dust hydration treatment tank 2-7, a slurry (lump) transport vehicle 2-8, an environmentally friendly building material preparation station 2-9, a fine screener 3-1, a manual shut-off valve 3-2 for the heating gas circuit, an automatic regulating valve 3-3, a bypass valve 3-4, a check valve 4-9, a manual shut-off valve 4-2 for the power generation circuit, an automatic regulating valve 4-3, a bypass valve 4-1 for the power generation circuit, an expansion power generation equipment 4-4, an air-water heat exchange station 4-5, a heating station 4-6, a hot water reflux pump 4-7 and a softened water-constant pressure water supply system 4-8.

[0058] The waste heat ash transport vehicle 1-2 adopts a bucket transport vehicle, which travels back and forth between the calcination and thermal reduction furnace 1-1 to collect and transport high-temperature waste heat ash to the waste heat ash transport plate 1-3. The transport end of the waste heat ash transport plate 1-3 is connected to the funnel-type slag inlet 2-1-200 of the spiral screen type pulverizing slag furnace 2-1, and the high-temperature waste heat ash is transported from a low place to the funnel-type slag inlet 2-1-200; the inlet of the cyclone dust collector 2-4 is connected to a hot air ash mixed flow outlet 2-1-600 of the spiral screen type pulverizing slag furnace 2-1, and the outlet is connected to the inlet of the fine screen 3-1, and the high-pressure fan 2-2 outlet It is connected to the high-pressure cooling air inlet 2-1-500 of the spiral screen type pulverizing slag furnace 2-1 through a flange and a pipeline. The manual stop valve 3-2 and the automatic regulating valve 3-3 of the heating gas circuit are connected in sequence with the first pipeline. The second pipeline where the bypass valve 3-4 of the heating gas circuit is located is connected in parallel with the first pipeline where the manual stop valve 3-2 and the automatic regulating valve 3-3 are located. The calcination and thermal reduction furnace 1-1 and the fine screener 3-1 are connected to the front and back with the third pipeline and the fourth pipeline respectively. One end of the gas-water heat exchange station 4-5 gas side pipeline is connected to the third pipeline through the fifth pipeline. The fifth pipeline is provided with a check valve 4-9. The gas The other end of the gas-side pipeline of the water heat exchange station 4-5 is connected to the gas outlet of the expansion power generation equipment 4-4. The manual stop valve 4-2 and the automatic regulating valve 4-3 of the power generation circuit are connected in sequence with flanges and pipelines. The bypass valve 4-1 of the power generation circuit is connected in parallel with the manual stop valve 4-2 and the automatic regulating valve 4-3 of the power generation circuit by pipelines, and the gas inlet of the expansion power generation equipment 4-4 and the gas outlet of the fine screener 3-1 are connected in front and back. The fine screener 3-1 adopts a filtration accuracy of 1200 mesh or more; one end of the water side of the gas-water heat exchange station 4-5 is connected to the heating station 4-6 by pipeline, and the other end is connected to the hot water reflux pump 4-7 pipeline. The hot water reflux pump 4-7 is connected at one end to the pipeline outlet of the heating station 4-6, and at the other end is connected to the softened water-constant pressure water supply system 4-8; the dust hydration treatment pool 2-7 is connected to the fly ash outlet of the cyclone dust collector 2-4 with an asbestos cloth belt, and one end of the grey water booster pump 2-6 is connected to the grey water pool 2-5, which collects the grey water in the park to save water resources, and the other end is connected to the spray equipment of the dust hydration treatment pool 2-7 with a pipeline; the slurry (lump) transport vehicle 2-8 travels back and forth between the dust hydration treatment pool 2-7 and the environmentally friendly building materials preparation station 2-9 to transport the slurry lumps after hydration treatment.

[0059] The one-way equalizing pressure valve 2-3 is connected to the high-pressure cooling air (30-60°C) inlet 2-1-500 and another hot air ash mixed flow outlet 2-1-600 of the spiral screen type pulverizing slag furnace 2-1 to connect the upper and lower spaces of the furnace body to avoid local pressure buildup and instability of the furnace body due to screen blockage. When the ash screen is blocked, the pressure on the upper part of the furnace body increases sharply, and the one-way equalizing pressure valve 2-3 is pushed open by the upper high pressure to connect the upper and lower parts of the furnace body. The high-pressure ash wind enters the pipe connected to the hot air ash mixed flow outlet 2-1-600 from the high-pressure cooling air inlet 2-1-500 through the one-way equalizing pressure valve 2-3 and its connected bypass pipe to relieve pressure. At the same time, the system issues a fault alarm, the waste hot ash transport plate 1-3 stops running, and the high-pressure cold air generated by the high-pressure fan 2-2 blows the ash screen to achieve self-cleaning. After the furnace pressure is balanced and the one-way equalizing pressure valve 2-3 is closed, the waste hot ash transport plate 1-3 is restarted and the system continues to operate.

[0060] Example 3

[0061] A low-carbon and environmentally friendly method for recovering waste heat from solid waste, comprising:

[0062] When the solid waste waste heat recovery low-carbon environmental protection system is started, the calcination and thermal reduction furnace 1-1 has completed the dolomite calcination and thermal reduction process in the first Pijiang process magnesium smelting, and the calcined residue and thermal reduction slag (800℃-1000℃) are collected and mixed, and then transported by the waste heat ash transport vehicle 1-2 to the waste heat ash transport plate 1-3 loading port for unloading, and then lifted by the waste heat ash transport plate 1-3 to the funnel-type slag inlet 2-1-1 of the spiral screen type pulverization slag furnace 2-1. 200; Before the slag is fed in, the plug-in sealer 2-1-300 and the hydraulic rotary sealer 2-1-400 of the spiral screen type pulverizing slag furnace 2-1 are both in a closed state; when the waste slag enters the bottom of the funnel type slag inlet 2-1-200, the closed plug-in sealer 2-1-300 is opened, and the waste slag falls into the furnace body 2-1-100 under the action of gravity; at this time, the hydraulic rotary sealer 2-1-400 is in a closed state, and the waste slag is completely accumulated. After the rotary sealing plates 2-1-420 (1) and 2-1-420 (2) are on, the sealing plates in the plate sealer 2-1-300 are closed to isolate the furnace body 2-1-100 from the external environment through the funnel-type slag inlet 2-1-200. Then, the rotary sealing plates 2-1-420 (1) and 2-1-420 (2) are opened to allow the waste slag to continue to fall and enter the ash spiral screen 2-1-110 to start heat exchange and sieving the ash spiral screen 2-1-110. After 1-110, the rotary sealing plates 2-1-420(1) and 2-1-420(2) are closed to wait for the next batch of waste slag to enter the furnace body; the rotary sealing plates 2-1-420(1) and 2-1-420(2) of the plug-in sealer 2-1-300 and the hydraulic rotary sealer 2-1-400 are opened and closed in this way to ensure that the spiral screen type pulverizing slag furnace 2-1 works uninterruptedly under the condition of intermittent feeding of waste hot ash and isolate the furnace body from the external environment.

[0063] After the waste slag enters the furnace body, the plug-in closer 2-1-300 is closed, the high-pressure fan 2-2 is started and the rotary sealing plate 2-1-420 is closed to send high-pressure cooling air into the furnace body; the waste hot ash is gradually cooled and screened along the ash spiral screen 2-1-110 under the combined action of gravity and high-pressure cooling air, and the high-pressure cold air forms a vortex along the central support guide column 2-1-120 and the ash spiral screen 2-1-110 in the closed space of the furnace body, fully contacting and exchanging heat with the waste hot ash, and the surface temperature of the waste hot ash gradually cools down, and gradually ashes and falls off under the contact friction of the high-pressure cold air, and the particle size of the waste hot ash is reduced, and the first-level spiral ash primary screen 2-1-111, the first-level spiral ash secondary screen 2-1-112, and the second-level spiral ash screen 2-1-110 are screened. The array sieve holes on the primary screen 2-1-113, the secondary spiral ash secondary screen 2-1-114, the tertiary spiral ash primary screen 2-1-117, and the tertiary spiral ash secondary screen 2-1-116 are gradually reduced in size, so that ash of different particle sizes can be in contact with the cooling air in layers for heat exchange in the furnace body, thereby increasing the heat exchange area and improving the heat exchange efficiency. The primary side fine screen 2-1-115 and the secondary side fine screen 2-1-118 perform two-dimensional filtration in two steps to stagnate the wind speed and improve the separation efficiency of small slag particles and the air-ash mixed flow. Finally, the fly ash after step-by-step filtration forms a high-temperature air-ash two-phase mixed flow with the wind at 400-500°C, flows from top to bottom along the ash spiral screen 2-1-110 to the hot air-ash mixed flow outlet 2-1-600, and enters the cyclone dust collector 2-4.

[0064] The high-temperature air-ash two-phase mixed flow is separated and dusted by the cyclone dust collector 2-4, and the fly ash is transported from the bottom of the cyclone dust collector 2-4 through the asbestos belt into the dust hydration treatment pool 2-7. The dust hydration treatment pool 2-7 adopts a semi-open closed type to achieve the purpose of dust reduction and heat dissipation.

[0065] Furthermore, the grey water booster pump 2-6 draws grey water from the grey water pool 2-5 and enters the dust reduction cooling sprayer of the dust hydration treatment pool 2-7 to cool the stored high-temperature dust and form a slurry on the sedimentation plate, which is then transported by the slurry (slurry) transport vehicle 2-8 to the environmentally friendly building material preparation station 2-9 for solid waste treatment to produce building materials such as calcium silicate boards and environmentally friendly bricks.

[0066] Furthermore, the high-temperature wind carries a small amount of dust into the fine screen 3-1 for secondary dust removal, and then enters the expansion power generation equipment 4-4 through the manual stop valve 4-2 and the automatic regulating valve 4-3 of the power generation circuit to drive the generator to generate electricity. The generated electricity is connected to the internal power grid of the magnesium smelting plant to reduce power consumption. The power generation circuit bypass valve 4-1 serves as a backup bypass for the automatic regulating valve 3-3 gas circuit. It is closed during normal operation and opened when the automatic regulating valve 3-3 gas circuit fails to ensure the stable operation of the power generation equipment. The high-temperature wind generates electricity through the expansion power generation equipment 4-4 to complete the utilization of high-grade waste heat, and its pressure and temperature are reduced. After the pressure is reduced and the temperature is lowered, the hot wind enters the gas-water heat exchange station 4-5 again to exchange heat with water to realize the recovery and utilization of low-grade waste heat. After the low-grade waste heat is recovered and utilized, it is reduced again. The heated hot air is connected to the calcination and thermal reduction furnace 1-1 through the gas transportation pipeline to preheat or assist in heating materials such as dolomite and semi-coke, thereby completing the final waste heat recovery; the circulating water of the gas-water heat exchange station 4-5 is prepared and replenished by the softened water-constant pressure water replenishment system 4-8, and the circulating water after heat exchange and heating is introduced into the heating station 4-6 through the hot water pipeline for use. The circulating water after cooling down in the heating station is pressurized by the hot water reflux pump 4-7 and then enters the gas-water heat exchange station 4-5 again for recycling.

[0067] Furthermore, when the expansion power generation equipment 4-4, the gas-water heat exchange station 4-5 or the heating station 4-6 fails, is overhauled or stops operating, the manual stop valve 4-2, the automatic regulating valve 4-3 and the bypass valve 4-1 of the power generation circuit are closed, and the high-temperature hot air enters the calcination and thermal reduction furnace 1-1 from the manual stop valve 3-2 and the automatic regulating valve 3-3 of the heating gas circuit to preheat or assist in heating the materials. The bypass valve 3-4 serves as a spare maintenance valve to ensure the safety and stability of the gas circuit.

[0068] Furthermore, according to the waste heat recovery and utilization operation strategy, the heating gas circuit and the power generation circuit can be started simultaneously, and the automatic control valve 3-3 and the automatic control valve 4-3 are used to distribute the high-temperature air flow to distribute and utilize the waste heat energy.

[0069] The term "consisting of" when describing a combination should include the identified elements, ingredients, components, or steps as well as other elements, ingredients, components, or steps that do not materially affect the basic novel characteristic of the combination. The use of the terms "comprising" or "including" to describe a combination of elements, ingredients, components, or steps herein also contemplates embodiments consisting essentially of these elements, ingredients, components, or steps. The use of the term "may" herein is intended to indicate that any of the attributes described as "may" be optional.

[0070] Multiple elements, ingredients, parts or steps can be provided by a single integrated element, ingredient, part or step. Alternatively, a single integrated element, ingredient, part or step can be divided into separate multiple elements, ingredients, parts or steps. The disclosure of "a" or "an" to describe an element, ingredient, part or step is not intended to exclude other elements, ingredients, parts or steps.

[0071] It should be understood that the above description is for illustrative purposes only and is not intended to be limiting. Many embodiments and many applications beyond the examples provided will be apparent to those skilled in the art upon reading the above description. Therefore, the scope of the present teachings should not be determined with reference to the above description, but rather with reference to the preceding claims and the full scope of equivalents to which such claims are entitled. For the purpose of completeness, all articles and references, including disclosures of patent applications and publications, are incorporated herein by reference. The omission of any aspect of the subject matter disclosed herein from the preceding claims is not a disclaimer of such subject matter, nor should it be considered that the applicants did not consider such subject matter to be part of the disclosed inventive subject matter.

Claims

1. A spiral screen type pulverizing slag furnace, characterized in that: It comprises a furnace body (2-1-100), wherein the upper part of the furnace body (2-1-100) is provided with a slag inlet, a plug-in plate closer (2-1-300) and a hydraulic rotary closer (2-1-400) in sequence from top to bottom; The furnace body (2-1-100) is provided with a central support guide column (2-1-120) and an ash spiral screen (2-1-110) fixed on the furnace body wall and the central support guide column (2-1-120); the inner edge of the ash spiral screen (2-1-110) is fixedly connected to the vertical surface of the support guide column (2-1-120), and the outer edge is fixedly connected to the inner wall surface of the furnace body; The furnace body (2-1-100) is provided with a high-pressure cooling air inlet (2-1-500) and a hot air-ash mixed flow outlet (2-1-600); The ash spiral screen (2-1-110) comprises a first-stage spiral ash primary screen (2-1-111), a first-stage spiral ash secondary screen (2-1-112), a second-stage spiral ash primary screen (2-1-113), a second-stage spiral ash secondary screen (2-1-114), and a primary-side fine screen (2-1-115) which are connected in sequence according to the sieve holes from large to small, and a third-stage spiral ash primary screen (2-1-117), a third-stage spiral ash secondary screen (2-1-116), and a secondary-side fine screen (2-1-118) which are fixedly connected in sequence according to the sieve holes from small to large.

2. A spiral screen type pulverizing slag furnace according to claim 1, characterized in that: The hydraulic rotary sealer (2-1-400) comprises a rotary shaft, a rotary sealing plate (2-1-420) and a hydraulic actuator (2-1-410); two rotary sealing plates (2-1-420) are rotatably connected to the rotary shaft; the rotary sealing plate (2-1-420) comprises a lever-arm type semicircular sealing plate (2-1-421) and a sliding locking pin (2-1-424); the lever-arm type semicircular sealing plate (2-1-421) comprises a sleeve, a semicircular sealing plate and a lever; the head end of the lever is clamped on the rotary shaft through the sleeve; The hydraulic actuator (2-1-410) includes an inner bearing support seat (2-1-412), a flange head (2-1-413), a slide rail support seat (2-1-411), a radial hydraulic actuator cylinder (2-1-414), and a circumferential hydraulic actuator cylinder (2-1-415); the inner bearing support seat (2-1-412) is rotatably connected to the rotating shaft, and the slide rail support seat (2-1-411) is provided with an arc-shaped slide groove; the two ends of the slide rail support seat (2-1-411) are respectively fixedly connected to the inner bearing support cylinder seat (2-1-412) through two connecting rods; a first connecting member and a second connecting member are installed on the two connecting rods, a first positioning screw is fixed on the first connecting member, and a second positioning screw is fixed on the second connecting member; the flange head (2-1-413) is fixed to the end of the bearing support seat (2-1-412); The sliding locking pin (2-1-424) passes through the slide groove and is fixedly connected to the end of the force arm; the cylinder end ring of the radial hydraulic actuator (2-1-414) is sleeved on the first positioning screw, the top ring of the hydraulic rod of the radial hydraulic actuator (2-1-414) is sleeved on the middle part of the circumferential hydraulic actuator (2-1-415), the cylinder end ring of the circumferential hydraulic actuator (2-1-415) is sleeved on the second positioning screw, and the top ring of the hydraulic rod of the circumferential hydraulic actuator (2-1-415) and the top ring of the hydraulic rod are both concentrically sleeved with the sliding locking pin (2-1-424).

3. The spiral screen type pulverizing slag furnace according to claim 1, characterized in that: The inner channel of the slag inlet is connected to the insert plate closer (2-1-300), a square groove is provided in the middle of the insert plate closer (2-1-300), and a horizontally movable sealing plate is provided in the square groove.

4. The spiral screen type pulverizing slag furnace according to claim 1, characterized in that: The first-level spiral ash primary screen (2-1-111) includes a first-level spiral primary screen guide plate (2-1-111-1) provided with a first-level spiral primary screen array hole (2-1-111-2), the first-level spiral ash secondary screen (2-1-112) includes a first-level spiral secondary screen guide plate (2-1-112-1) provided with a first-level spiral secondary screen array hole (2-1-112-2), the second-level spiral ash primary screen (2-1-113) includes a second-level spiral primary screen guide plate (2-1-113-2) provided with a second-level spiral primary screen array hole (2-1-113-3). 1), the secondary spiral ash secondary screen (2-1-114) includes a secondary spiral secondary screen guide plate (2-1-114-1) provided with a secondary spiral secondary screen array hole (2-1-114-2), the tertiary spiral ash primary screen (2-1-117) includes a tertiary spiral primary screen guide plate (2-1-117-1) provided with a tertiary spiral primary screen array hole (2-1-117-2), and the tertiary spiral ash secondary screen (2-1-116) includes a tertiary spiral secondary screen guide plate (2-1-116-1) provided with a tertiary spiral secondary screen array hole (2-1-116-2).

5. The spiral screen type pulverizing slag furnace according to claim 4, characterized in that: The aperture of the first-level spiral primary screen array hole (2-1-111-2) is 40-50 mm, the aperture of the first-level spiral secondary screen array hole (2-1-112-2) is 30-40 mm, and the aperture of the second-level spiral primary screen array hole (2-1-113-2) is 20-30 mm; the aperture of the second-level spiral secondary screen array hole (2-1-114-2) is 15-20 mm; the aperture of the third-level spiral primary screen array hole (2-1-117-2) is 5-10 mm, and the aperture of the third-level spiral secondary screen array hole (2-1-116-2) is 2-5 mm; the primary side fine screen (2-1-115) adopts a 5-mesh screen, and the secondary side fine screen (2-1-118) adopts a 100-mesh or larger screen.

6. The spiral screen type pulverizing slag furnace according to claim 1, characterized in that: The furnace body (2-1-100) is a vertical cylindrical tank with a wall thickness greater than 20 mm. The furnace body (2-1-100) is covered with an inorganic insulation body.

7. A low-carbon and environmentally friendly system for recovering waste heat from solid waste, characterized in that: It comprises a calcining and thermal reduction furnace (1-1), a waste heat ash transport plate (1-3), a high-pressure fan (2-2), a cyclone dust collector (2-4), a reclaimed water tank (2-5), a reclaimed water booster pump (2-6), a dust hydration treatment tank (2-7), an environmentally friendly building material preparation station (2-9), a fine screener (3-1), an expansion power generation device (4-4), an air-water heat exchange station (4-5), a heating station (4-6), a hot water reflux pump (4-7), a softened water-constant pressure water supply system (4-8), and a spiral screen type pulverizing slag furnace according to claim 1; The head end of the waste heat ash transport plate (1-3) is used to receive the high-temperature waste heat ash generated by the calcination and thermal reduction furnace (1-1), and the transport end of the waste heat ash transport plate (1-3) is connected to the slag inlet; the inlet of the cyclone dust collector (2-4) is connected to a hot air ash mixed flow outlet (2-1-600) of the spiral screen type pulverizing slag furnace (2-1), and the outlet is connected to the inlet of the fine screen (3-1), and the outlet of the high-pressure fan (2-2) is connected to the spiral screen type pulverizing slag furnace (2-1). The high-pressure cooling air inlet (2-1-500) of the screen-type pulverizing slag furnace (2-1) is connected, and the gas outlet of the fine screen (3-1) is connected to the gas inlet of the calcining and thermal reduction furnace (1-1) and the expansion power generation equipment (4-4) through pipelines; the gas outlet of the expansion power generation equipment (4-4) is connected to the gas side pipeline inlet of the gas-water heat exchange station (4-5), and the gas side pipeline outlet of the gas-water heat exchange station (4-5) is connected to the calcining and thermal reduction furnace (1-1); One end of the water side of the air-water heat exchange station (4-5) is connected to the heating station (4-6), and the other end is connected to the hot water reflux pump (4-7). One end of the hot water reflux pump (4-7) is connected to the pipeline outlet of the heating station (4-6), and the other end is connected to the softened water-constant pressure water replenishment system (4-8); the dust hydration treatment pool (2-7) is connected to the fly ash outlet of the cyclone dust collector (2-4) through a cloth belt, one end of the reclaimed water booster pump (2-6) is connected to the reclaimed water pool (2-5), and the other end is connected to the spray equipment of the dust hydration treatment pool (2-7) by a pipeline. The environmentally friendly building material preparation station (2-9) is used to treat the mud mass obtained by hydration treatment as solid waste.

8. A low-carbon and environmentally friendly system for recovering waste heat from solid waste according to claim 7, characterized in that: It also includes a manual stop valve (3-2) for the heating gas circuit, an automatic regulating valve (3-3) and a bypass valve (3-4) for the heating gas circuit, wherein the manual stop valve (3-2) and the automatic regulating valve (3-3) for the heating gas circuit are installed on a first pipeline, a second pipeline where the bypass valve (3-4) for the heating gas circuit is located is connected in parallel with the first pipeline where the manual stop valve (3-2) and the automatic regulating valve (3-3) are located, and the third pipeline and the fourth pipeline are connected to the calcining and thermal reduction furnace (1-1) and the fine screen (3-1) respectively; The manual shut-off valve (4-2) and the automatic regulating valve (4-3) of the power generation circuit are connected in sequence via flanges and pipelines; the bypass valve (4-1) of the power generation circuit is connected in parallel with the manual shut-off valve (4-2) and the automatic regulating valve (4-3) of the power generation circuit via pipelines, and are connected front and back to the gas inlet of the expansion power generation device (4-4) and the gas outlet of the fine screener (3-1).

9. A method for recovering waste heat from solid waste, characterized in that: A low-carbon and environmentally friendly system for recovering waste heat from solid waste according to claim 8 comprises the following steps: When the solid waste waste heat recovery low-carbon environmental protection system is started, the calcination and thermal reduction furnace (1-1) has completed the dolomite calcination and thermal reduction process in the first Pijiang process magnesium smelting, and the calcined residue and thermal reduction slag are collected and mixed, and then transported to the charging port of the waste heat ash transport plate (1-3) for unloading, and lifted to the slag inlet by the waste heat ash transport plate (1-3), and enter the spiral screen type pulverization slag furnace for waste heat recovery; Before slag is fed in, the insert plate sealer (2-1-300) and the hydraulic rotary sealer (2-1-400) of the spiral screen type pulverizing slag furnace (2-1) are both in a closed state; when the waste slag enters the bottom of the funnel type slag inlet (2-1-200), the insert plate sealer (2-1-300) is opened in sequence to allow the waste slag to fall onto the rotary sealing plate (2-1-420) of the hydraulic rotary sealer (2-1-400), and then the insert plate sealer (2-1-300) is closed to allow the waste slag to enter the furnace body, and then the hydraulic rotary sealer (2-1-400) is closed; After the waste slag enters the furnace body, the rotary sealing plate (2-1-420) and the plug-in plate sealer (2-1-300) are closed to put the furnace body in a closed state, and the high-pressure fan (2-2) is started to send high-pressure cooling air into the furnace body; under the combined action of gravity and high-pressure cooling air, the waste hot ash is gradually cooled and screened along the ash spiral screen (2-1-110), and the high-pressure cold air is blown along the central support guide column (2-1- 120) and the ash spiral screen (2-1-110) form a vortex, fully contacting and exchanging heat with the waste hot ash, so that the waste hot ash is gradually cooled and ashed, the particle size is reduced, and the sieve falls; the fly ash and the wind form a high-temperature air-ash two-phase mixed flow of (400-500) ° C, and flow from top to bottom along the ash spiral screen (2-1-110) to the hot air-ash mixed flow outlet (2-1-600), and enter the cyclone dust collector (2-4) for air-ash separation and dust removal; The high-temperature air-ash two-phase mixed flow is separated and dusted in the cyclone dust collector (2-4), and the fly ash is transported from the bottom of the cyclone dust collector (2-4) to the dust hydration treatment pool (2-7) via a cloth belt; The reclaimed water booster pump (2-6) draws reclaimed water from the reclaimed water pool (2-5) and enters the dust reduction cooling sprayer of the dust hydration treatment pool (2-7) to cool the stored high-temperature dust and form a slurry on the sedimentation plate. The slurry is then transported to the environmentally friendly building material preparation station (2-9) for solid waste treatment and manufactured into building materials such as calcium silicate boards and environmentally friendly bricks. The high-temperature wind carries a small amount of dust into the fine screen (3-1) for secondary dust removal, and then enters the expansion power generation equipment (4-4) to drive the generator to generate electricity.

10. A solid waste waste heat recovery method according to claim 9, characterized in that: After the high-temperature wind performs work in the expansion power generation equipment (4-4), it enters the gas-water heat exchange station (4-5) to exchange heat with water and then cool down again. Then, it enters the calcination and thermal reduction furnace (1-1) through the gas transportation pipeline to preheat or auxiliary heat the materials in the calcination and thermal reduction furnace (1-1), thereby completing the final waste heat recovery. The circulating water of the gas-water heat exchange station (4-5) is prepared and replenished by the softened water-constant pressure water replenishment system (4-8). The circulating water heated by heat exchange is introduced into the heating station (4-6) for use through the hot water pipeline. The circulating water used in the heating station (4-6) is pressurized by the hot water reflux pump (4-7) and then enters the gas-water heat exchange station (4-5) again for recycling.

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