CN110818303A

CN110818303A - Production process for calcining building gypsum by using phosphogypsum

Info

Publication number: CN110818303A
Application number: CN201911272837.0A
Authority: CN
Inventors: 赵嘉珩; 赵建纲
Original assignee: ZHENGZHOU SUNDY BUILDING TECHNOLOGY Co Ltd
Current assignee: ZHENGZHOU SUNDY BUILDING TECHNOLOGY Co Ltd
Priority date: 2019-12-12
Filing date: 2019-12-12
Publication date: 2020-02-21

Abstract

A production process for calcining building gypsum by phosphogypsum belongs to the field of phosphogypsum calcination, and comprises the following steps: 1. sending the industrial byproduct phosphogypsum into a sunlight shed; 2. reducing water in a sunlight shed, and adding a neutralizer for neutralization after water reduction; 3. conveying the neutralized phosphogypsum into an outer furnace body of the comprehensive furnace by adopting a conveying device for heating and dehydrating; 4. feeding the heated and dehydrated phosphogypsum into a calcining furnace for calcining; 5. feeding the phosphogypsum calcined by the calcining furnace into a waste heat self-calcining bin body for aging; has the characteristics of simple process, continuous production and high energy utilization rate.

Description

Production process for calcining building gypsum by using phosphogypsum

Technical Field

The invention belongs to the field of phosphogypsum calcination, and particularly relates to a production process for calcining industrial byproduct phosphogypsum into building gypsum powder.

Background

The phosphogypsum is a byproduct in the production process of phosphorus chemical enterprises, and is not directly applied, so that the phosphogypsum is accumulated for a long time to cause a large amount of overstocked accumulation and becomes a pollution source for generating secondary pollution, and therefore, the resource utilization of the phosphogypsum is a problem to be solved urgently in the industry; in order to solve the problem, the applicant previously applied Chinese patent (application number: 2019104604978) to solve the problem of resource utilization of phosphogypsum, and phosphogypsum is calcined to form high-strength building gypsum; firstly, the preheating furnace in the original application adopts a straight-through tube type preheating furnace, and waste heat after calcining of a calcining furnace is used for heating phosphogypsum in the preheating furnace through an intermediate tube so as to reduce the water content of the phosphogypsum and save calcining energy; on the contrary, because the tail gas of the calcining furnace contains a large amount of moisture, the dust collecting bag of the rear-stage dust remover is seriously bonded with the gypsum powder, and the dust collecting bag needs to be frequently replaced even if electric heating is adopted; secondly, because the temperature of the gypsum powder calcined by the calcining furnace is inconsistent and higher, the temperature of the reducing furnace is overhigh after the gypsum powder enters the reducing furnace and is difficult to cool, so that the reduction effect of the gypsum powder is poor; thirdly, the process is complicated and the quality consistency of the finished gypsum powder is poor due to unreasonable equipment.

Disclosure of Invention

In order to overcome the problems of the existing phosphogypsum calcining process, the invention discloses a process method for calcining building gypsum by phosphogypsum, which has the advantages of simple and effective process, simplified equipment and high energy utilization rate, and the technical scheme is realized in such a way, and the production process for calcining building gypsum by phosphogypsum is characterized in that: the method comprises the following steps: 1. sending the industrial byproduct phosphogypsum into a sunlight shed; 2. reducing water in a sunlight shed, and neutralizing after water reduction; 3. conveying the neutralized phosphogypsum into an outer furnace body of the comprehensive furnace by adopting a conveying device for heating and dehydrating; 4. feeding the heated and dehydrated phosphogypsum into a calcining furnace for calcining; 5. feeding the phosphogypsum calcined by the calcining furnace into a waste heat self-calcining bin body for aging; 6. feeding the phosphogypsum subjected to waste heat self-calcination bin body aging into an inner cylinder of a comprehensive furnace; 7. sending the phosphogypsum sent out from the comprehensive furnace inner cylinder into a homogenizing device for homogenizing; 8. coating the homogenized phosphogypsum by a coating device; 9. and (4) conveying the coated phosphogypsum into a finished product bin for storage or a next procedure for deep processing.

The method comprises the following steps that step 1, the byproduct phosphogypsum in the production process of phosphorus chemical enterprises is conveyed to a sunlight shed by a conveying or transporting tool, and the temperature in the shed is increased by utilizing solar energy, so that the temperature of the phosphogypsum entering the sunlight shed is increased, and the moisture volatilization speed is increased.

And 2, increasing the temperature of the phosphogypsum entering the sunlight shed to accelerate the volatilization of moisture contained in the phosphogypsum, simultaneously percolating the phosphogypsum in the sunlight shed to separate out the moisture and waste liquid contained in the phosphogypsum, entering a recovery pond to achieve the effect of reducing water, then quantitatively adding a neutralizing agent according to the pH value of the phosphogypsum, wherein the neutralizing agent is preferably quicklime, and adjusting the pH value of the phosphogypsum so as to be better applied to building construction.

Step 3, the phosphogypsum subjected to dewatering and neutralization in the sunlight shed is sent into a comprehensive furnace, and the heat of calcined phosphogypsum powder is utilized to heat the uncalcined phosphogypsum, so that the water content of the uncalcined phosphogypsum is further reduced, the calcining efficiency is improved for the next step of calcining the phosphogypsum, and the preparation for saving calcining energy is made; the comprehensive furnace is characterized in that: the device comprises an inner cylinder, a rear wrapping head, a connecting piece, an outer cylinder material pushing plate, a front wrapping head, a feeding hole, an exhaust pipe, an inner cylinder rotary joint, an inner cylinder discharging device, an outer cylinder and a discharging hole; the inner cylinder is arranged in the outer cylinder, has the same axle center with the outer cylinder, is connected with the outer cylinder through a connecting piece and can synchronously rotate with the outer cylinder; the rear wrapping head is arranged at the rear end of the outer barrel, wraps the rear end part of the outer barrel, and is in sealed relative rotation connection with the rear end of the outer barrel; the connecting piece is arranged between the inner cylinder and the outer cylinder, is respectively and fixedly connected with the outer cylinder and the inner cylinder, and can enable the inner cylinder and the outer cylinder to synchronously rotate; the outer cylinder material pushing plates are arranged on the inner wall of the outer cylinder, and are distributed in an interval spiral inclined shape, the spiral direction is a material pushing direction and is opposite to the direction of the material pushing plates on the inner wall of the inner cylinder; the front wrapping head is arranged at the feed end of the outer barrel, the front end of the outer barrel is wrapped in the front wrapping head, and an elastic sealing device is arranged at the contact part of the outer wall of the outer barrel and the outer wall of the inner barrel, so that the front wrapping head, the inner barrel and the outer barrel can be prevented from leaking when the outer barrel and the inner barrel rotate; the feed inlet is arranged on the front wrapping head, is communicated with the inner cavity of the front wrapping head and is butted with the feed inlet of the outer barrel; the exhaust pipe is arranged on the front wrapping head, one end of the exhaust pipe is communicated with the inner cavity of the outer barrel, and the other end of the exhaust pipe is connected with the dust remover through a fan; the outlet part of the exhaust pipe is provided with a branch pipeline which is communicated with the inner cavity of the inner cylinder; the inner cylinder rotary joint is arranged at the end part of the inner cylinder, one end of the inner cylinder rotary joint is connected with the inner cylinder in a rotary sealing way, and the other end of the inner cylinder rotary joint is connected with the inner cylinder discharging device; the two inner cylinder rotary joints are respectively arranged at two ends of the inner cylinder; the inner cylinder discharging device is arranged at one end of the inner cylinder rotary joint and is hermetically connected with the inner cylinder rotary joint, and the outlet of the inner cylinder discharging device is connected with a conveying device of the next process; the outer cylinder is arranged at the periphery of the inner cylinder and is a cylindrical body which is coaxial with the inner cylinder; the outer circumference of the outer cylinder is provided with a driving device and a supporting device, and the outer cylinder can rotate on the supporting device under the driving of the driving device; the discharge port is arranged on the rear wrapping head and communicated with the inner cavity of the outer barrel.

Furthermore, the inner wall of the inner cylinder is provided with a plurality of material pushing plates, and the material pushing direction is opposite to that of the material pushing plates of the outer cylinder.

The working principle of the comprehensive furnace is that the waste heat is adopted to enter the inner cylinder of the comprehensive furnace from the aged phosphogypsum in the calcining bin body, because the inner cylinder is made of metal materials, the heat conductivity is good, the temperature of the aged phosphogypsum is higher and is generally more than 200 ℃, the temperature is about 60 ℃ higher than the original temperature of the waste heat of a calcining furnace, the heating efficiency of the raw material phosphogypsum is improved, favorable conditions are provided for dehydrating the raw material phosphogypsum, meanwhile, the aged phosphogypsum can be reduced into semi-hydrated gypsum to be used as building gypsum only by cooling and adding water, the hot phosphogypsum passing through the inner cylinder heats the raw material phosphogypsum on the one hand, and simultaneously cools the hot phosphogypsum, thus being favorable for the bidirectional process, air is introduced into the inner cylinder from an exhaust pipe, the moisture is increased while the phosphogypsum in the inner cylinder is cooled, because the moisture is extracted by the exhaust pipe after the raw material, the extracted air contains a large amount of water, so that the problems of cooling and water adding of the aged phosphogypsum are solved, the problem of dehydration of the raw material phosphogypsum is solved, the energy is repeatedly and comprehensively utilized, and the production efficiency is improved.

Step 4, primarily dehydrated phosphogypsum output from the comprehensive furnace is sent into a calcining furnace for calcining, the calcining furnace is a double-barrel calcining furnace, and the calcining process is to add the primarily dehydrated phosphogypsum sent out from the comprehensive furnace into an outer barrel of the double-barrel calcining furnace from a feed inlet of the calcining furnace; the inner side of the outer cylinder is heated and moves forwards, the heated and moved forward enters the inner cylinder through the cone guide from the outer cylinder to the inner cylinder when the heated and moved forward to the tail end of the outer cylinder, the tail part of the inner cylinder moves to the front end of the inner cylinder, a flame spraying furnace arranged at the front port of the inner cylinder sprays flame to the inner cavity of the inner cylinder, the phosphogypsum is burned after encountering the phosphogypsum, and the burned phosphogypsum is sent out to a discharging and conveying device through a discharging port arranged at the front end of the inner.

Furthermore, the burning temperature of the phosphogypsum in the calcining furnace is more than 360 ℃.

And 5, immediately conveying the calcined phosphogypsum to a waste heat self-calcining bin body through a heat-insulating conveying device, wherein the heat-insulating conveying device is formed by additionally arranging heat-insulating facilities on the peripheries of a conveying device such as a conveying belt and a bucket elevator.

The waste heat self-calcining bin bodies in the step 5 are heat-insulating bin bodies, calcined phosphogypsum can exchange heat fully in the bin bodies, the requirement of continuous production of the calcining furnace can be met, the waste heat self-calcining bin bodies are alternately aged to form continuous production, the aging time of the waste heat self-calcining bin bodies is set to be 0-48 hours, the phosphogypsum in the bin bodies can reach relative heat balance and reach the temperature required to be removed, and the temperature consistency of the phosphogypsum sent out from the calcining bin bodies by the waste heat can be realized.

Thus overcoming the defect that the quality of the produced phosphogypsum is unstable because the temperature of the calcined phosphogypsum is inconsistent and unstable, and the time and the amount of cooling and water adding are difficult to control after the calcined phosphogypsum enters a reduction stage.

And 6, conveying the aged phosphogypsum in the calcining bin body into an inner barrel of the comprehensive furnace by adopting a conveying device, on one hand, heating the raw material phosphogypsum in the outer barrel of the comprehensive furnace by utilizing the waste heat, and on the other hand, cooling and adding water by self.

And 7, feeding the phosphogypsum discharged from the inner cylinder of the comprehensive furnace into a homogenizing device, wherein the homogenizing device is a bin body, and uniformly mixing the phosphogypsum in the bin body to keep consistency so as to ensure that the set coating parameters are stable when the coating process is carried out.

After the aged phosphogypsum passes through the comprehensive furnace, the cooling and water adding degrees of the phosphogypsum are not uniform and have randomness, so that the performance can be kept consistent after further homogenization is needed, and a consistent processing process can be obtained after the phosphogypsum enters the next procedure to obtain a phosphogypsum product with consistent performance.

Step 8 is to send the homogenized phosphogypsum into a coating device for coating process, the shape of the gypsum crystal can be finished in the coating process, the specific surface area of the gypsum crystal is improved, and various performances of the gypsum powder are greatly improved, which is specifically disclosed in the previously applied Chinese patent (application number: 2019103065744).

And 9, conveying the coated phosphogypsum into a finished product bin for storage, or directly conveying the coated phosphogypsum into a gypsum product production process for deep processing, such as gypsum board production, gypsum block production and the like.

All the steps are completed in the phosphogypsum calcining equipment, and the phosphogypsum calcining equipment is characterized in that: the device comprises a sunlight shed, a front neutralization device, a first conveying device, a comprehensive furnace, a second conveying device, a homogenizing device, a coating device, a finished product bin, a third conveying device, a calcining furnace, a fourth conveying device, a waste heat self-calcining bin body, a rear neutralization device, a fifth conveying device, a sixth conveying device, a raw material phosphogypsum quantitative conveying device, a flame-throwing furnace, a dust remover and a seventh conveying device; the sunlight shed is arranged at the front end of the comprehensive furnace, can improve the indoor air temperature by utilizing sunlight to achieve the purpose of evaporating the water content of the phosphogypsum raw material, and simultaneously separates out waste liquid contained in the phosphogypsum raw material by an infiltration device at the bottom of the sunlight shed and intensively recycles the waste liquid; the front neutralizing device is arranged in the sunlight shed and connected with a phosphogypsum raw material conveying device after water is volatilized and waste liquid is separated out, and quick lime is quantitatively and uniformly fed into the phosphogypsum raw material to be mixed with the phosphogypsum raw material; the first conveying device is arranged between the sunlight shed and the comprehensive furnace, one end of the first conveying device is connected with the discharge conveying device of the sunlight shed, and the other end of the first conveying device is connected with the feed inlet of the comprehensive furnace; the comprehensive furnace is arranged between the sunlight shed and the calcining furnace, a feed inlet of the comprehensive furnace is connected with the first conveying device, and a discharge outlet of the comprehensive furnace is connected with the third conveying device; the inner cylinder feed inlet of the comprehensive furnace is connected with the sixth conveying device, and the inner cylinder discharge outlet is connected with the second conveying device; the second conveying device is arranged between the discharge port of the inner cylinder of the comprehensive furnace and the homogenizing device, the feeding end is connected with the discharge port of the inner cylinder of the comprehensive furnace, and the discharging end is connected with the feed port of the homogenizing device; the homogenizing device is arranged between the second conveying device and the coating device, the feeding end is connected with the second conveying device, the discharging end is connected with the coating device through a conveying tool, and the homogenized phosphogypsum in the homogenizing device can be conveyed into the coating device to be coated; the coating device is arranged between the homogenizing device and the finished product bin and is respectively connected with the homogenizing device and the finished product bin through the conveying device; the transportation device is a transportation vehicle or a conveying device; the finished product bin is arranged at the rear end of the coating device and can store finished gypsum powder; the third conveying device is arranged between the comprehensive furnace and the calcining furnace, a feed port of the third conveying device is connected with a discharge port of the comprehensive furnace, and the discharge port of the third conveying device is connected with a feed port of the calcining furnace; the calcining furnace is arranged between the third conveying device and the fourth conveying device, a feed inlet of the calcining furnace is connected with a discharge end of the third conveying device, and a discharge outlet of the calcining furnace is connected with a feed inlet of the fourth conveying device; the fourth conveying device is arranged between the calcining furnace and the waste heat self-calcining bin body, a feed inlet of the fourth conveying device is connected with a discharge outlet of the calcining furnace, and a discharge outlet of the fourth conveying device is connected with a feed inlet of the waste heat self-calcining bin body; the fourth conveying device is a combination of a plurality of conveying devices, and can convey the phosphogypsum discharged from the discharge hole of the calcining furnace to the feed holes of different waste heat self-calcining bin bodies according to different time periods; the fourth conveying device is a conveying device with a heat-preserving cover at the periphery; the waste heat self-calcining bin body is a bin body, wherein a heat insulation layer is wrapped outside the inner wall of metal, and is arranged between the fourth conveying device and the fifth conveying device; the waste heat self-calcining bin bodies are multiple, and a feed inlet of each waste heat self-calcining bin body is connected with a discharge outlet of the fourth conveying device; the rear neutralization device is arranged on one side of the fifth conveying device and is a quantitative conveying device, and a discharge port of the rear neutralization device is connected with the fifth conveying device, namely, quantitative quicklime can be conveyed to the fifth conveying device and mixed with the phosphogypsum; the fifth conveying device is arranged between the waste heat self-calcining bin body and the sixth conveying device, the feeding end of the fifth conveying device is connected with the discharging port of the waste heat self-calcining bin body, the discharging port of the fifth conveying device is connected with the feeding end of the sixth conveying device, and the phosphogypsum sent out by the waste heat self-calcining bin body can be conveyed to the sixth conveying device and conveyed into the inner cylinder of the comprehensive furnace through the sixth conveying device; the sixth conveying device is arranged between the fifth conveying device and the comprehensive furnace, a feed port of the sixth conveying device is connected with a discharge port of the fifth conveying device, and a discharge port of the sixth conveying device is connected with a feed port of an inner cylinder of the comprehensive furnace; the quantitative conveying device for the raw material phosphogypsum is arranged at a discharge port of the calcining furnace, the discharge port of the quantitative conveying device is communicated with the interior of the discharge port of the calcining furnace, and the quantitative conveying device can convey the phosphogypsum raw material which is not subjected to any treatment to an outlet of the calcining furnace and convey the phosphogypsum raw material into a fourth conveying device along with the calcined phosphogypsum; the flame-throwing furnace is arranged at the front end of the calcining furnace, and a flame-throwing hole of the flame-throwing furnace faces to an opening at the front end of an inner cylinder of the calcining furnace and can jet flame to the inner cylinder of the calcining furnace; the dust remover is arranged at the rear end of the calcining furnace, and an air inlet of the dust remover is connected with the calcining furnace and an air outlet pipe of the comprehensive furnace through a pipeline; the air outlet pipe of the dust remover is the same as the atmosphere; the seventh conveying device is positioned between the sunlight shed and the quantitative conveying device for the raw material phosphogypsum, is a conveying tool or a conveying device, and can convey or convey the raw material phosphogypsum to the quantitative conveying device for the raw material phosphogypsum.

Further, the calcining furnace is a double-cylinder rotary calcining furnace.

Furthermore, in order to overcome the defects that the prior calcining equipment adopts a bag type dust collector to generate more energy consumption and is easy to bond with a filter bag, the tail temperature of the calcining furnace is low, and the volatile gas contains a large amount of water, and the water is condensed when being cooled and is combined with gypsum powder to form an adhesive, so that the filter bag of the bag type dust collector is frequently replaced, and the operation cost is increased; therefore, the dust remover adopted by the invention is a water dust remover, and is characterized in that: comprises an air inlet, a main body, a water tank, a vacuum dewatering belt and an air outlet; the air inlet is communicated with an air outlet pipe of the calcining furnace and an outer barrel air outlet pipe of the comprehensive furnace through a pipeline and extends into a water tank in the main body; the main body is a hollow cavity, a water tank and a sediment lifting device are arranged in the main body, the water tank is arranged at the lower part of the main body, and water is filled in the water tank; the sediment lifting device is arranged in the water tank and is positioned below the water surface, and a discharge port of the sediment lifting device is connected with a feed end of the vacuum dewatering belt; the water tank is positioned at the lower part of the vacuum dehydration belt, an upper opening cavity body which can contain water and is not leaked is formed, one end positioned in the main body is communicated with the water tank, and the port at one end positioned at the outer end of the vacuum dehydration belt is closed; the vacuum dewatering belt is arranged on the main body, the inner end of the vacuum dewatering belt is positioned in the main body and is connected with the discharge hole of the sediment lifting device, and the outer end of the vacuum dewatering belt is connected with the feed inlet of the comprehensive furnace or the discharge hole of the calcining furnace through a conveying device or a conveying device; the air outlet is arranged on the main body and is positioned above the water tank, the inlet of the air outlet is higher than the highest water surface in the water tank, and the outer end of the air outlet is communicated with the atmosphere.

The connection means that the discharge hole of one device corresponds to the feed hole of the other device, and the conveyed materials can enter the feed hole of the other device from the discharge hole.

In order to improve the stability of the gypsum powder and facilitate the application in building construction, quicklime is added into the phosphogypsum for neutralization so as to adjust the pH value of a phosphogypsum product and prevent the performance of a building member from being influenced by the pH value; firstly, adding quicklime into phosphogypsum subjected to infiltration and moisture volatilization in a sunlight shed by adopting a quantitative conveying belt, adding the quicklime into aged phosphogypsum by adopting the quantitative conveying device from a discharge end of a calcining bin body by adopting waste heat, and adding the quicklime with the weight ratio of 0-15% according to the PH value of the phosphogypsum into the total amount of the quicklime.

In order to increase the temperature stability of the calcined phosphogypsum, a method of adding a raw material phosphogypsum into the calcined phosphogypsum is also adopted, and the specific method is that the raw material phosphogypsum is added into the calcined phosphogypsum at a discharge port of a calcining furnace by adopting a quantitative conveying device; the method has the advantages that dust at the discharge port of the calcining furnace can be pressed to raise, the loss of the phosphogypsum is reduced, and meanwhile, the added phosphogypsum raw material does not need to be calcined, so that the energy is saved; moreover, the total temperature of the calcined phosphogypsum can be adjusted, and the temperature of the phosphogypsum entering the waste heat self-calcining bin body is ensured to be consistent.

Advantageous effects

The method has the advantages of simplifying the calcining process of the phosphogypsum, fully utilizing energy, reducing maintenance and repair cost and ensuring the quality consistency of the gypsum powder product.

Drawings

FIG. 1 is a schematic diagram of the layout of the apparatus of the present invention

1. The device comprises a sunlight shed, 2. a front neutralization device, 3. a first conveying device, 4. a comprehensive furnace, 5. a second conveying device, 6. a homogenizing device, 7. a cladding device, 8. a finished product bin, 9. a third conveying device, 10. a calcining furnace, 11. a fourth conveying device, 12. a waste heat self-calcining bin body, 13. a rear neutralization device, 14. a fifth conveying device, 15. a sixth conveying device, 16. a raw material phosphogypsum quantitative conveying device, 17. a spraying furnace, 18. a dust remover, 19. a seventh conveying device.

FIG. 2 is a schematic view of the construction of an integrated furnace according to the present invention

41. The device comprises an inner cylinder, 42 parts of a rear wrapping head, 43 parts of a connecting piece, 44 parts of an outer cylinder pushing plate, 45 parts of a front wrapping head, 46 parts of a feeding hole, 47 parts of an exhaust pipe, 48 parts of an inner cylinder rotary joint, 49 parts of an inner cylinder discharging device, 40 parts of an outer cylinder and 401 parts of a discharging hole.

FIG. 3 is a schematic view of the structure of the dust collector of the present invention

181. The air inlet 182, the main body 183, the water tank 184, the vacuum dewatering belt 185 and the air outlet.

Detailed Description

In order to further explain the technical scheme of the invention, the specific implementation mode of the invention is explained by combining the accompanying drawings, as shown in fig. 1-3, in the embodiment, a sunlight shed of a previously applied Chinese patent (application number: 2019112561546) is selected as a sunlight shed 1 and is arranged near a phosphogypsum production and collection yard; a belt conveyor belt which is commonly used in the industry is selected as a first conveying device, the first conveying device is arranged between a sunlight shed 1 and a comprehensive furnace 4, a feeding end is connected with an outlet of a phosphogypsum loading device such as a forklift and the like in the sunlight shed 1, and a discharging end is connected with a feeding port of an outer barrel of the comprehensive furnace 4; in the embodiment, a quantitative conveying belt commonly known as a belt scale is selected as a front neutralization device 2 and a rear neutralization device 13, the front neutralization device 2 is arranged in a sunlight shed 1, the feeding end is connected with the discharging port of a quicklime storage device, and the discharging end is connected with the feeding end of a first conveying device 3, namely, the quicklime sent from the front neutralization device 2 is quantitatively conveyed to the feeding end of the first conveying device 3; the post-neutralization device 13 is arranged on one side of the fifth conveying device 14, the feeding end is connected with the discharging port of the quicklime storage device, and the discharging end is in butt joint with the fifth conveying device 14, namely, the quicklime sent out from the discharging end of the post-neutralization device 13 can quantitatively enter the phosphogypsum on the conveying surface of the fifth conveying device 14; selecting a belt conveyor and a bucket elevator which are commonly used in the industry as a second conveying device 5, taking the belt conveyor as a preceding-stage conveying device to be connected with a discharge hole of an inner cylinder of the comprehensive furnace 4, connecting a discharge end of the belt conveyor with the lower end of the bucket elevator, installing the bucket elevator on a homogenizing device 6, connecting the lower end of the bucket elevator with the discharge end of the belt conveyor, and connecting the upper end of the bucket elevator with a feed inlet at the upper end of the homogenizing device 6; in the embodiment, a metal turning tank commonly used in the industry is selected as a homogenizing device 6, the upper end opening is a feeding hole, and the lower end opening is a discharging hole; the homogenizing device 6 is arranged between the second conveying device 5 and the coating device 7; in this example, the coating device 7 is configured by the method of the previously applied Chinese patent (application number: 2019103065744), and the phosphogypsum homogenized by the homogenizing device 6 is sent to the coating device 7 by a transport means such as a vehicle for coating treatment; in the embodiment, a vertical tank commonly used in the industry is selected as a finished product bin 8, and the coated phosphogypsum is conveyed to the finished product bin 8 by a conveying tool for storage; in the embodiment, a belt conveying device commonly used in the industry is selected as a third conveying device 9, the third conveying device 9 is arranged between the outer cylinder discharge port of the comprehensive furnace 4 and the feed port of the calcining furnace 10, the feed end of the third conveying device is connected with the outer cylinder discharge port of the comprehensive furnace 4, and the discharge end of the third conveying device is connected with the feed port of the calcining furnace 10; in the embodiment, a double-barrel calcining furnace commonly used in the industry is selected as the calcining furnace 10, the calcining furnace 10 is arranged obliquely below the comprehensive furnace 4, a feed inlet of the calcining furnace 10 is in butt joint with a discharge end of a third conveying device 9, and a discharge outlet of the calcining furnace 10 is in butt joint with a fourth conveying device 11; in the embodiment, a plurality of belt conveyors which are commonly used in the industry are combined to form a bucket elevator, a heat insulation layer is wrapped on the periphery of the bucket elevator to form a fourth conveying device 11, the number of the branch belt conveyors is respectively matched with that of the bucket elevators, the number of the bucket elevators is matched with that of the waste heat self-calcining bin bodies 12, each waste heat self-calcining bin body 12 is provided with one bucket elevator, and a partition plate is arranged on the main belt conveyor to control the feeding and closing of each branch belt conveyor; in the embodiment, the residual heat self-calcining bin body in the Chinese patent (application number: 2019112559014) previously applied by the applicant is selected as the residual heat self-calcining bin body 12 in the embodiment, the output of the calcining furnace 10 is 20 tons/hour, 4 residual heat self-calcining bin bodies 14 are arranged, each capacity is 120 tons, the aging time is 6 hours, the continuous operation of the calcining furnace 10 can be ensured, the residual heat self-calcining bin bodies 12 are aged in turn, and the continuous production of the whole calcining equipment can be ensured; in the embodiment, a scraper conveying machine which is commonly used in the industry is selected as a fifth conveying device 14, the fifth conveying device 14 is arranged below the waste heat self-calcining bin body 12 and corresponds to a discharge port of the waste heat self-calcining bin body 12, and the discharge end is connected with a feed end of a sixth conveying device 15; in the embodiment, a belt conveyor which is commonly used in the industry is selected as the sixth conveying device 15, and the sixth conveying device 15 is arranged between the discharge end of the fifth conveying device 14 and the feeding hole of the inner cylinder of the comprehensive furnace 4; respectively connected with the fifth conveying device 14 and the inner cylinder feed inlet of the comprehensive furnace 4; in the embodiment, a belt scale which is commonly used in the industry is selected as a raw material gypsum quantitative conveying device 16, the belt scale is arranged at a discharge port of a calcining furnace 10 and is controlled to be matched with the output of the calcining furnace 10, the weight ratio of the added raw material phosphogypsum is 0-20%, the adding amount is adjusted according to the discharge temperature of the calcining furnace 10, the added raw material phosphogypsum is a byproduct of industrial phosphogypsum which is not subjected to any treatment, and the reason why the calcined lime is added again by a neutralizing device 13 after the addition is also reason; in the embodiment, a gas flaming furnace which is commonly used in the industry is selected as the flaming furnace 17, and the flaming furnace is arranged at the front end of the calcining furnace 10, and the flaming direction faces to an opening of an inner cylinder of the calcining furnace; in the embodiment, a water dust removal device is selected as the dust remover 18, an air inlet 181 of the dust remover 18 is connected with the calcining furnace 10 and an outer cylinder exhaust pipe 47 of the comprehensive furnace 4 through pipelines, a fan is arranged in the middle of the pipeline, the air inlet 181 enters the water surface in the main body 182, an opening is arranged on the side edge of the main body 2, a water tank 183 is arranged, a vacuum dehydration belt 184 is arranged in the water tank 183, a sediment lifting device is arranged at the end part of the vacuum dehydration belt 184 in the main body, and an air outlet 185 is communicated with the atmosphere through a pipeline; thus, even if the moisture content in the air extracted by the calcining furnace 10 and the comprehensive furnace 4 is higher, the problem of bonding and damage of the filter bag existing in the bag type dust collector adopted in the prior art can not be caused; in the embodiment, a preheating kiln before phosphogypsum calcination is selected from a Chinese patent (application number: 2019102494371) previously applied by the applicant, a hot air pipe in the previously applied patent is enlarged in diameter (optimally, the diameter of the inner cylinder is smaller than the inner diameter of the outer cylinder 40 and is more than or equal to the radius of the outer cylinder 40) to be used as the inner cylinder 41, a material pushing plate is arranged on the inner wall of the inner cylinder 41 to be used as the comprehensive furnace 4 in the embodiment, and the comprehensive furnace 4 is arranged obliquely above the calcining furnace 10, so that the feeding from the comprehensive furnace 4 to the calcining furnace 10 is facilitated, and the conveying distance is reduced; the feeding hole of the inner cylinder 41 of the comprehensive furnace 4 is butted with the discharging end of the sixth conveying device 15, the feeding hole 46 of the outer cylinder 40 is connected with the discharging end of the first conveying device 3, the two ends of the inner cylinder 41 are connected with the inner cylinder rotating joint 48, the outer part of the left end rotating joint of the inner cylinder 41 is connected with the feeding hole of the inner cylinder, the outer part of the right end rotating joint is provided with the discharging hole of the inner cylinder, the discharging hole 401 is butted with the feeding end of the third conveying device 9, the exhaust pipe 47 is connected with the air inlet 181 of the dust remover 18 through a pipeline, and a branch pipeline is led out to be communicated with the inner cavity of the inner cylinder 41.

When in application, the phosphogypsum is discharged from phosphorus chemical enterprises, is sent into a sunlight shed 1 for water volatilization and percolation, is sent into an outer cylinder 40 of a comprehensive furnace 4 for heating and dehydration after adding quicklime, the heat source of the phosphogypsum is from high-temperature phosphogypsum discharged from a calcining bin body 12 by waste heat to enter an inner cylinder 41, and simultaneously, the phosphogypsum in the outer cylinder 40 cools the high-temperature phosphogypsum in the inner cylinder 41, because the phosphogypsum can generate phase change only when cooled to a certain temperature, and anhydrous gypsum is converted into dihydrate gypsum; the gypsum calcined by the calciner 10 is sent to a residual heat self-calcining bin body 12 for long-time aging, and the aging is usually carried out for 0 to 48 hours; the aged phosphogypsum is used for heating the raw material gypsum in the outer cylinder 40 of the comprehensive furnace through the inner cylinder 41 of the comprehensive furnace 4 to reduce water; homogenizing by a homogenizing device 6, then performing a coating process, and then entering a finished product bin 8 for storage; because the volatilization and infiltration of the sunlight shed 1 are adopted, the solar energy and natural infiltration are fully utilized, and the energy is saved; due to the adoption of the heat exchange mode of the comprehensive furnace 4, the energy is further saved, and the energy utilization rate is improved; because the waste heat self-calcining bin body 12 is adopted, the calcined phosphogypsum is in a consistent state, the stability of the reduction process of the calcined phosphogypsum is kept, and the stability of the quality of the phosphogypsum calcined building gypsum is improved; because the water dust collector is adopted, the air pollution is reduced, the energy is saved, the phosphogypsum dust is recycled, and the defects that the bag type dust collector needs electric heating and a filter bag is bonded by gypsum powder to cause failure and damage are overcome; because the raw material gypsum is added into the calcined gypsum powder, the self-calcining function of the high-temperature gypsum is fully utilized, the calcining energy and the process are saved, and the overall yield is improved.

Claims

1. A production process for calcining building gypsum by phosphogypsum is characterized by comprising the following steps: the method comprises the following steps: 1. sending the industrial byproduct phosphogypsum into a sunlight shed; 2. reducing water in a sunlight shed, and adding a neutralizer for neutralization after water reduction; 3. conveying the neutralized phosphogypsum into an outer furnace body of the comprehensive furnace by adopting a conveying device for heating and dehydrating; 4. feeding the heated and dehydrated phosphogypsum into a calcining furnace for calcining; 5. feeding the phosphogypsum calcined by the calcining furnace into a waste heat self-calcining bin body for aging; 6. feeding the phosphogypsum subjected to waste heat self-calcination bin body aging into an inner cylinder of a comprehensive furnace; 7. sending the phosphogypsum sent out from the comprehensive furnace inner cylinder into a homogenizing device for homogenizing; 8. coating the homogenized phosphogypsum by a coating device; 9. and (4) conveying the coated phosphogypsum into a finished product bin for storage or a next procedure for deep processing.

2. The production process of phosphogypsum calcined building gypsum according to claim 1, which is characterized in that: the steps 1-9 are completed by production equipment for phosphogypsum calcining construction.