Device for the harmless treatment of phosphogypsum by calcination using high-temperature ceramsite

Abstract

The present invention relates to the technical field of phosphogypsum dehydration treatment and provides a device for the harmless treatment of phosphogypsum by calcination using high-temperature ceramsite, comprising a rotary kiln, a first feeding component, a second feeding component, and a separation component; the rotary kiln comprises a first rotating drum and a second rotating drum; a first intermediate layer channel is formed between the first rotating drum and the second rotating drum, the initial end of the first intermediate layer channel communicating with the initial end of the first rotating drum; the first feeding component is used to introduce high-temperature ceramsite into the interior of the first rotating drum; the second feeding component is used to introduce phosphogypsum into the interior of the first intermediate layer channel;The mixture inside the first rotating drum and the phosphogypsum inside the first intermediate layer channel can exchange heat to dehydrate the phosphogypsum. The separation component is used to separate the mixture discharged from the first rotating drum, obtaining calcined phosphogypsum. The present invention offers high efficiency in the calcination and dehydration of phosphogypsum. It allows for its harmless, low-carbon treatment to obtain phosphate gypsum for construction.

Description

Device for the harmless treatment of phosphogypsum by calcination using high-temperature ceramsite CROSS REFERENCES

[0001] The present application claims priority of Chinese patent application No. 202310470395.0 entitled "Device for the harmless treatment of phosphogypsum by calcination using high temperature ceramsite", submitted on April 27, 2023, the full disclosure content of which is incorporated in its entirety into this document by reference. TECHNICAL FIELD

[0002] The present invention relates to the technical field of phosphogypsum dehydration treatment, and in particular to a device for the harmless treatment of phosphogypsum by calcination using high-temperature ceramsite. BACKGROUND OF THE INVENTION

[0003] Phosphogypsum is a byproduct of phosphoric acid production using the sulfuric acid method and, subsequently, of the production of high-concentration phosphate fertilizers. Phosphogypsum is composed primarily of calcium sulfate dihydrate and contains impurities such as phosphates, sulfates, fluorides, and heavy metals like manganese and cadmium, as well as traces of radioactive elements that require specialized treatment for safe handling. During prolonged storage of phosphogypsum, natural weathering activities such as sun exposure, wind, rain, and storms accelerate the release of soluble phosphorus, fluorine, and heavy metal contaminants. Acidic residues such as the soluble phosphorus contained in the phosphogypsum are again leached and filtered by precipitation, causing serious damage to the water quality, soil, and vegetation of the surrounding areas.Therefore, it is clearly necessary to make safe use of phosphogypsum to reduce phosphogypsum pollution to the surrounding environment.

[0004] Currently, utilizing phosphogypsum to produce gypsum-based building materials is the primary area of ​​exploration for expanding the utilization rate of phosphogypsum resources. The first step in using phosphogypsum in the production of gypsum-based building materials is to calcine and dehydrate the phosphogypsum to obtain gypsum powder. In the related techniques, the calcination and dehydration of phosphogypsum primarily utilize frying kilns, rotary kilns, fluidized bed kilns, and calcination equipment with integrated grinding and combustion, etc., which can remove some of the harmful impurities through combustion during the dehydration process. However, existing phosphogypsum calcination equipment still commonly exhibits low calcination and dehydration efficiency, making it difficult to achieve the safe treatment of phosphogypsum. SUMMARY OF THE INVENTION

[0005] The present invention provides a device for the harmless treatment of phosphogypsum by calcination using high-temperature ceramsite, in order to solve the problem that existing phosphogypsum calcination equipment has low calcination and dehydration efficiency, making it difficult to achieve the harmless treatment of phosphogypsum.

[0006] The present invention provides a device for the harmless treatment of phosphogypsum by calcination using high-temperature ceramsite, comprising: a rotating kiln, a first feeding component, a second feeding component, and a separation component;

[0007] Said rotary kiln comprises a first rotary drum and a second rotary drum; said second rotary drum is mounted on the outside of said first rotary drum; between said first rotary drum and said second rotary drum a first intermediate layer channel is formed, and the initial end of said first intermediate layer channel communicates with the initial end of said first rotary drum;

[0008] Said first feed component communicates with the initial end of said first rotary drum to introduce high-temperature ceramsite into said first rotary drum; said second feed component communicates with said first intermediate layer channel to introduce phosphogypsum into said first intermediate layer channel;

[0009] Said second rotating drum is used to propel the phosphogypsum along said first intermediate layer channel towards the initial end of said first rotating drum; said first rotating drum is used to propel the mixture composed of phosphogypsum and high-temperature ceramsite from the initial end of said first rotating drum towards the final end; the mixture in said first rotating drum and the phosphogypsum in said first intermediate layer channel can perform heat exchange through the drum wall of said first rotating drum, to perform the dehydration treatment of said phosphogypsum;

[0010] Said separation component is arranged at the end of said first rotating drum, to perform the separation of the mixture discharged from said first rotating drum, obtaining the calcined phosphogypsum.

[0011] According to the device for the harmless treatment of phosphogypsum by calcination using high-temperature ceramsite provided by the present invention, the inner wall of said first rotary drum and the inner wall of said second rotary drum are provided with helical feed vanes;

[0012] Where said first rotating drum and said second rotating drum can rotate in the same direction at the same speed or at different speeds.

[0013] According to the device for the harmless treatment of phosphogypsum by calcination using high-temperature ceramsite provided by the present invention, said rotary kiln further comprises a kiln head;

[0014] Said furnace head is annular in shape and is mounted around the peripheral wall of said second rotating drum; a feed chamber is formed between said furnace head and the peripheral wall of said second rotating drum; the peripheral wall of said second rotating drum is provided with a communication opening, said feed chamber communicates with said first intermediate layer channel through said communication opening;

[0015] Said second feeding component is connected to said furnace head to perform the introduction of said phosphogypsum into said feeding chamber.

[0016] According to the device for the harmless treatment of phosphogypsum by calcination using high-temperature ceramsite provided by the present invention, multiple such second rotating drums are provided;

[0017] Multiple said second rotary drums are successively mounted around the outside of said first rotary drum, between each two adjacent said second rotary drums a second intermediate layer channel is formed, multiple said second intermediate layer channels and said first intermediate layer channel communicate successively end to end from the outside to the inside, forming a serpentine conduit;

[0018] Said furnace head is mounted around the peripheral wall of the second rotating drum of the outermost layer, said feed chamber is formed between said furnace head and the second rotating drum of the outermost layer; the peripheral wall of the second rotating drum of the outermost layer is provided with a communication opening, said feed chamber communicates with said serpentine conduit through said communication opening;

[0019] Where the phosphogypsum transported by said second feed component can be transported along said serpentine conduit, eventually reaching the interior of said first rotating drum.

[0020] According to the device for the harmless treatment of phosphogypsum by calcination using high-temperature ceramsite provided by the present invention, in the event that the quantity of said second rotating drums is an odd number, said kiln head is arranged at the end of the second rotating drum of the outermost layer;

[0021] In the event that the quantity of said second rotating drums is an even number, said furnace head is arranged at the initial end of the second rotating drum of the outermost layer.

[0022] According to the device for the harmless treatment of phosphogypsum by calcination using high-temperature ceramsite provided by the present invention, inside said feeding chamber there is a feed mechanism arranged;

[0023] Said advance mechanism is used to propel the phosphogypsum inside said feed chamber through said communication opening into said first intermediate layer channel.

[0024] According to the device for the harmless treatment of phosphogypsum by calcination using high-temperature ceramsite provided by the present invention, it further comprises: an induced draft assembly;

[0025] One end of said induced draft assembly communicates with the end of said first rotating drum, the other end communicates with said feed chamber;

[0026] Where said induced draft assembly is used to propel the hot air discharged from the end of said first rotating drum back into said feed chamber.

[0027] According to the device for the harmless treatment of phosphogypsum by calcination using high-temperature ceramsite provided by the present invention, said induced draft assembly comprises a filtering component and an induced draft fan;

[0028] The end of said first rotating drum communicates with the air inlet of said induced draft fan through said filtering component, the air outlet of said induced draft fan communicates with said feed chamber.

[0029] According to the device for the harmless treatment of phosphogypsum by calcination using high-temperature ceramsite provided by the present invention, said induced-draft assembly comprises a cyclone separator and an induced-draft fan; the end of said first rotating drum communicates with the air inlet in the side wall of said cyclone separator, the air outlet at the top of said cyclone separator communicates with the air inlet of said induced-draft fan, the air outlet of said induced-draft fan communicates with said feed chamber, the bottom end of said cyclone separator is used to discharge the separated solid waste.

[0030] According to the device for the harmless treatment of phosphogypsum by calcination using high-temperature ceramsite provided by the present invention, said separation component comprises a first discharge channel, a separation screen, a second discharge channel, and a discharge hopper;

[0031] The end of said first rotating drum communicates with one end of said first discharge channel, the other end of said first discharge channel extends into the screening surface of said separation screen;

[0032] The material retained on the screen separated by said separation screen is discharged through said second discharge channel, the material passing through the screen separated by said separation screen is discharged through said discharge hopper.

[0033] The device for the harmless treatment of phosphogypsum by calcination using high-temperature ceramsite provided by the present invention, by configuring the rotary kiln, the first feed component, the second feed component, and the separation component, can introduce high-temperature ceramsite to the initial end of the first rotary drum through the first feed component, and introduce phosphogypsum into the interior of the first intermediate layer channel through the second feed component. Under the action of the rotating first and second drums, the phosphogypsum is fed along the first intermediate layer channel at the initial end of the first drum and mixed with the high-temperature ceramsite. The high-temperature ceramsite acts as a passivation treatment for the harmful gases produced during the high-temperature dehydration of the phosphogypsum. Utilizing the porous adsorption capacity of the high-temperature ceramsite, it absorbs the water vapor produced by the flash vaporization of the phosphogypsum upon contact with it, thus achieving negative pressure separation of the phosphogypsum and resulting in a flash calcination effect while reducing dust. As the first rotating drum transports the mixture composed of phosphogypsum and high-temperature ceramsite, utilizing the high-temperature action of the ceramsite, not only can the mixture inside the first rotating drum and the phosphogypsum inside the first intermediate layer channel perform heat exchange through the drum wall of the first rotating drum to perform high-temperature dehydration of the phosphogypsum continuously transported in the first intermediate layer channel, but also after the instantaneous calcination of the phosphogypsum by the high-temperature ceramsite, during the process of transporting the mixture, the residual heat of the ceramsite can be used to continue the calcination treatment of the phosphogypsum. Finally, the mixture discharged from the first rotating drum can be subjected to a separation treatment by the separation component, performing the separation of the large ceramsite particles and the fine particles of phosphate gypsum for construction.

[0034] As can be seen above, the device shown in the present invention can fully utilize high-temperature ceramsite to heat phosphogypsum, as well as to perform the adsorption treatment of harmful substances and water vapor produced during the dehydration treatment of the phosphogypsum. It can achieve high calcination and dehydration efficiency of phosphogypsum based on the rotary kiln, enabling the harmless, low-carbon treatment of phosphogypsum and the preparation of phosphate gypsum for construction. BRIEF DESCRIPTION OF THE DRAWINGS To explain more clearly the technical solutions of the present invention or the prior art, a brief introduction to the drawings needed in describing the embodiments or the prior art will follow. The drawings in the following description are clearly some embodiments of the present invention, and those skilled in the art can also obtain other drawings based on these without any further creative work.

[0036] Figure 1 is one of the structural schematic diagrams of the device for the harmless treatment of phosphogypsum by calcination using high-temperature ceramsite provided by the present invention;

[0037] Figure 2 is the structural schematic diagram of the rotary kiln of Figure 1 provided by the present invention;

[0038] Figure 3 is the second structural schematic diagram of the device for the harmless treatment of phosphogypsum by calcination using high-temperature ceramsite provided by the present invention;

[0039] Figure 4 is the third structural schematic diagram of the device for the harmless treatment of phosphogypsum by calcination using high-temperature ceramsite provided by the present invention;

[0040] Figure 5 is the structural schematic diagram of the rotary kiln of Figure 4 provided by the present invention;

[0041] Figure 6 is the fourth structural schematic diagram of the device for the harmless treatment of phosphogypsum by calcination using high-temperature ceramsite provided by the present invention;

[0042] Figure 7 is the structural schematic diagram of the rotary kiln of Figure 6 provided by the present invention. Numerical references for the figures:

[0043] 1, rotary kiln; 11, first rotary drum; 12, second rotary drum; 13, kiln head; 101, helical feed paddle; 111, first intermediate layer channel; 112, second intermediate layer channel;

[0044] 2, first power component; 3, second power component;

[0045] 4, separation component; 41, first discharge channel; 42, separation screen; 43, second discharge channel; 44, discharge hopper;

[0046] 5, induced draft assembly; 51, filtering component; 52, induced draft fan; 53, cyclone separator. DETAILED DESCRIPTION OF PREFERRED PRODUCTIONS

[0047] To clarify the objectives, technical solutions, and advantages of the present invention, the technical solutions of the present invention will now be clearly and completely described in conjunction with the drawings of the present invention. Clearly, the embodiments described are part of the embodiments of the present invention, but not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary practitioners in the field without creative work fall within the scope of protection of the present invention.

[0048] Next, in combination with Figures 1-7, the device for the harmless treatment of phosphogypsum by calcination using high-temperature ceramsite provided by embodiments of the present invention will be described in detail through specific embodiments and their application scenarios.

[0049] As shown in Figures 1 to 7, embodiments of the present invention provide a device for the harmless treatment of phosphogypsum by calcination using high-temperature ceramsite, comprising: a rotary kiln 1, a first feed component 2, a second feed component 3, and a separation component 4.

[0050] The rotary kiln 1 comprises a first rotary drum 11 and a second rotary drum 12; the second rotary drum 12 is mounted around the outside of the first rotary drum 11; a first intermediate layer channel 111 is formed between the first rotary drum 11 and the second rotary drum 12, the initial end of the first intermediate layer channel 111 communicating with the initial end of the first rotary drum 11.

[0051] The first feed component 2 communicates with the initial end of the first rotary drum 11, to introduce high-temperature ceramsite into the interior of the first rotary drum 11; the second feed component 3 communicates with the first intermediate layer channel 111, to introduce phosphogypsum into the interior of the first intermediate layer channel 111.

[0052] The second rotary drum 12 is used to propel the phosphogypsum along the first intermediate layer channel 111 towards the initial end of the first rotary drum 11; the first rotary drum 11 is used to propel the mixture composed of phosphogypsum and high-temperature ceramsite from the initial end of the first rotary drum 11 towards the final end; the mixture inside the first rotary drum 11 and the phosphogypsum inside the first intermediate layer channel 111 can perform heat exchange through the drum wall of the first rotary drum 11, to perform the dehydration treatment of the phosphogypsum.

[0053] Separation component 4 is arranged at the end of the first rotary drum 11, to perform the separation of the mixture discharged from the first rotary drum 11, obtaining the calcined phosphogypsum.

[0054] It is understandable that the phosphogypsum of this embodiment may specifically be a phosphogypsum premix with a temperature above 60°C, free water content <10% and organic matter content of 5~20% by weight.

[0055] The high-temperature ceramsite of this embodiment is specifically ceramsite with a temperature >800°C and exhibiting a visible flame. Optionally, the ceramsite density <1200 kg / m³, the average particle diameter <31.5 mm, and the porosity >30%.

[0056] In some examples, both the first feed component 2 and the second feed component 3 of this embodiment can be configured as hopper-shaped structures.

[0057] In some examples, both the first rotary drum 11 and the second rotary drum 12 of the rotary kiln 1 can be considered as having rotary drive mechanisms to rotate the first and second rotary drums in the same direction at the same speed or at different speeds. Material transport structures are configured on both the inner wall of the first and second rotary drums.

[0058] As the first rotary drum 11 and the second rotary drum 12 rotate, the phosphogypsum carried by the second feed component 3 into the first intermediate layer channel 111 can be gradually transported to the initial end of the first rotary drum 11 under the impulse of the material transport structure on the inner wall of the second rotary drum 12; correspondingly, the mixture composed of phosphogypsum and high-temperature ceramsite can gradually move from the initial end of the first rotary drum 11 to the final end under the impulse of the material transport structure on the inner wall of the first rotary drum 11.

[0059] In some examples, separation component 4 can be understood as a component with a mesh structure. Separation component 4 is used to receive the mixture discharged from the end of the first rotary drum 11. Separation component 4 can process the mixture discharged from the first rotary drum 11 by screening, obtaining large ceramsite particles as material retained on the screen, and fine particles of phosphate gypsum for construction as material passing through the screen.

[0060] The present invention, by configuring the rotary kiln 1, the first feed component 2, the second feed component 3 and the separation component 4, can introduce high-temperature ceramsite to the initial end of the first rotary drum 11 through the first feed component 2, and introduce phosphogypsum into the interior of the first intermediate layer channel 111 through the second feed component 3. Under the action of the rotation of the first rotary drum 11 and the second rotary drum 12, the phosphogypsum is fed along the first intermediate layer channel 111 to the initial end of the first rotary drum 11 and mixed with the high-temperature ceramsite. The high-temperature ceramsite acts as a passivation agent for the oxidizing gases produced during the high-temperature dehydration of the phosphogypsum. Utilizing the porous adsorption capacity of the high-temperature ceramsite, it absorbs the water vapor produced by the flash vaporization of the phosphogypsum upon contact with it, thus achieving negative pressure separation of the phosphogypsum and resulting in a flash calcination effect while reducing dust. As the first rotary drum 11 transports the mixture composed of phosphogypsum and high-temperature ceramsite, utilizing the high-temperature action of the ceramsite, not only can the mixture inside the first rotary drum 11 and the phosphogypsum inside the first intermediate layer channel 111 perform heat exchange through the drum wall of the first rotary drum 11 to perform high-temperature dehydration of the phosphogypsum continuously transported in the first intermediate layer channel 111, but also after the instantaneous calcination of the phosphogypsum by the high-temperature ceramsite, during the process of transporting the mixture, the residual heat of the ceramsite can be used to continue the calcination treatment of the phosphogypsum. Finally, the mixture discharged from the first rotating drum 11 can be subjected to a separation treatment by the separation component 4, performing the separation of the large ceramsite particles and the fine particles of phosphate gypsum for construction.

[0061] As can be seen above, the device shown in the present invention can fully utilize high-temperature ceramsite to heat phosphogypsum, as well as to perform the adsorption treatment of harmful substances and water vapor produced during the dehydration treatment of the phosphogypsum. It can achieve high calcination and dehydration efficiency of phosphogypsum based on the rotary kiln 1, enabling the harmless, low-carbon treatment of phosphogypsum and the preparation of phosphate gypsum for construction.

[0062] In some embodiments, as shown in Figures 1 to 7, both the inner wall of the first rotating drum 11 and the inner wall of the second rotating drum 12 are provided with helical feed vanes 101.

[0063] Where the first rotating drum 11 and the second rotating drum 12 can rotate in the same direction at the same speed or at different speeds.

[0064] In this way, when the first rotary drum 11 rotates, the first rotary drum 11 can drive the rotation of the helical feed paddles 101 on the inner wall of the first rotary drum 11, thereby guiding the mixture from the initial end of the first rotary drum 11 to the final end based on the helical feed paddles 101.

[0065] Correspondingly, when the second rotary drum 12 rotates, the second rotary drum 12 can drive the rotation of the helical feed paddles 101 on the inner wall of the second rotary drum 12, thereby guiding the phosphogypsum from the end of the first intermediate layer channel 111 to the beginning end based on the helical feed paddles 101, reaching the beginning end of the first rotary drum 11 and mixing with the high-temperature ceramsite.

[0066] In practical application, this embodiment can control the feed rate of the first rotary drum 11 and the second rotary drum 12 over the material in their corresponding cavities by controlling the rotation speed of the first rotary drum 11 and the second rotary drum 12.

[0067] In some embodiments, as shown in Figures 1 and 3, the rotary kiln 1 further comprises a kiln head 13. The kiln head 13 is annular in shape and mounted around the peripheral wall of the second rotary drum 12. A feed chamber is formed between the kiln head 13 and the peripheral wall of the second rotary drum 12. The peripheral wall of the second rotary drum 12 is provided with a communication opening, and the feed chamber communicates with the first intermediate layer channel 111 through this opening. The second feed component 3 connects to the kiln head 13 to introduce the phosphogypsum into the feed chamber.

[0068] It is understandable that the furnace head 13 of this embodiment is fixedly arranged, the inner surface of the furnace head 13 and the peripheral wall of the second rotating drum 12 perform a sliding seal, to form a hermetic feed chamber between the furnace head 13 and the peripheral wall of the second rotating drum 12.

[0069] Whereas the communication opening of this embodiment can be configured to extend along the extension direction of the furnace head 13, to facilitate that after the second feed component 3 introduces the phosphogypsum into the feed chamber, the phosphogypsum in the feed chamber can enter the interior of the first intermediate layer channel 111 through the communication opening.

[0070] Evidently, this embodiment facilitates feeding the second feed component 3 into the interior of the second rotary drum 12, which is arranged rotaryly based on the arrangement of the furnace head 13.

[0071] In some embodiments, as shown in Figures 4 to 7, multiple second rotary drums 12 are provided, multiple second rotary drums 12 are mounted successively around the outside of the first rotary drum 11, between each pair of adjacent second rotary drums 12 a second intermediate layer channel 112 is formed, multiple second intermediate layer channels 112 and the first intermediate layer channel 111 communicate successively end-to-end from the outside to the inside, forming a serpentine duct.

[0072] The furnace head 13 is mounted around the peripheral wall of the second rotary drum 12 of the outermost layer; between the furnace head 13 and the second rotary drum 12 of the outermost layer, the feed chamber is formed; the peripheral wall of the second rotary drum 12 of the outermost layer is provided with a communication opening; the feed chamber communicates with the serpentine duct through the communication opening.

[0073] Where the phosphogypsum transported by the second feed component 3 can be transported along the serpentine conduit, eventually reaching the interior of the first rotating drum 11.

[0074] It is understandable that this embodiment, by successively assembling multiple second rotary drums 12 around the outside of the first rotary drum 11, causes the outside of the first intermediate layer channel 111 to successively form multiple layers of second intermediate layer channels 112 from the inside out.

[0075] Where the end end of the first intermediate layer channel 111 communicates with the start end of the first rotary drum 11, the start end of the first intermediate layer channel 111 communicates with the end end of the inner multi-layer second intermediate layer channel 112, the start end of the inner multi-layer second intermediate layer channel 112 communicates with the end end of the second inner multi-layer second intermediate layer channel 112, the start end of the second inner multi-layer second intermediate layer channel 112 communicates with the end end of the third inner multi-layer second intermediate layer channel 112, and so on, the second intermediate layer channel 112 of the outermost layer communicates with the feed chamber through the communication opening.

[0076] Where, along the material transport direction inside the first rotary drum 11, the initial end of the first rotary drum 11 is upstream of the final end of the first rotary drum 11; along the material transport direction inside the first intermediate layer channel 111, the initial end of the first intermediate layer channel 111 is upstream of the final end of the first intermediate layer channel 111; along the material transport direction inside the second intermediate layer channel 112, the initial end of the second intermediate layer channel 112 is upstream of the final end of the second intermediate layer channel 112.

[0077] As the first rotary drum 11 and multiple second rotary drums 12 rotate, the phosphogypsum carried by the second feed component 3 to the feed chamber can be transported along the aforementioned serpentine conduit, from the intermediate layer channel located in the outer layer to the intermediate layer channel located in the inner layer layer by layer, until it reaches the interior of the first rotary drum 11.

[0078] Evidently, during the layer-by-layer transport process of the phosphogypsum, the phosphogypsum located in the first intermediate layer channel 111 or the second intermediate layer channel 112 can exchange heat with the mixture inside the first rotating drum 11, to perform the dehydration treatment of the phosphogypsum during the layer-by-layer transport process of the phosphogypsum, achieving an efficient utilization of the thermal energy of the high-temperature ceramsite, ensuring both the dehydration treatment effect of the phosphogypsum and energy savings.

[0079] In some embodiments, in the case where the number of second rotating drums 12 is an odd number, the furnace head 13 is arranged at the end of the second rotating drum 12 of the outermost layer.

[0080] In the case where the number of second rotary drums 12 is an even number, the furnace head 13 is arranged at the initial end of the second rotary drum 12 of the outermost layer.

[0081] This embodiment, based on the arrangement of the position of the furnace head 13, can ensure the length of the serpentine conduit formed by the second intermediate layer channels 112 and the first intermediate layer channel 111, being favorable to extend as much as possible the transport time of the phosphogypsum along the serpentine conduit, achieving an effective dehydration treatment of the phosphogypsum during the transport process.

[0082] As shown in Figures 1 to 3, a second rotary drum 12 is arranged, the furnace head 13 is arranged at the end of the second rotary drum 12. At this time, only the first intermediate layer channel 111 is arranged between the first rotary drum 11 and the second rotary drum 12.

[0083] As shown in Figures 4 and 5, two second rotating drums 12 are arranged, with the furnace head 13 positioned at the initial end of the second rotating drum 12 in the outermost layer. At this point, the first intermediate layer channel 111 is positioned between the first rotating drum 11 and the second rotating drum 12 located in the inner layer, and the second intermediate layer channel 112 is positioned between the second rotating drum 12 located in the inner layer and the second rotating drum 12 located in the outer layer.

[0084] As shown in Figures 6 and 7, three second rotating drums 12 are arranged, with the furnace head 13 positioned at the end of the outermost layer of the second rotating drum 12. The first intermediate layer channel 111 is positioned between the first rotating drum 11 and the first inner layer of the three second rotating drums 12, and a second intermediate layer channel 112 is positioned between the first inner layer and the second inner layer of the three second rotating drums 12, as well as between the second inner layer and the outermost layer of the three second rotating drums 12.

[0085] In some embodiments, a feed mechanism is arranged inside the feed chamber mentioned above. The feed mechanism is used to push the phosphogypsum inside the feed chamber through the communication opening into the first intermediate layer channel 111.

[0086] Where the feed mechanism can be a helical impeller, the helical impeller can be arranged between the discharge end of the second feed component 3 and the communication opening. The helical impeller can be configured to be coaxial with the discharge direction of the second feed component 3, thereby facilitating the propulsion of the phosphogypsum discharged from the second feed component 3 toward the communication opening.

[0087] Of course, the feed mechanism can also be arranged to include a telescopic drive component and a push plate, the output end of the telescopic drive component being connected to the push plate, the telescopic drive component being used to drive the reciprocating motion of the push plate, to drive the phosphogypsum in the feed chamber, towards the communication opening.

[0088] In some embodiments, as shown in Figures 1 and 3, the device of this embodiment is further configured with an induced draft assembly 5; one end of the induced draft assembly 5 communicates with the end of the first rotating drum 11, the other end communicates with the feed chamber.

[0089] Wherein the induced draft assembly 5 is used to drive the hot air discharged from the end of the first rotating drum 11 back into the feed chamber.

[0090] It is understandable that this embodiment can, under the impulse of the induced draft assembly 5, cause the hot air discharged from the end of the first rotating drum 11 to return to the feed chamber. This portion of the hot air, after entering the feed chamber, can enter the interior of the serpentine duct through the communication opening. The hot air, after undergoing convective heat exchange with the phosphogypsum transported in the serpentine duct, enters the beginning end of the first rotating drum 11, then reaches the end of the first rotating drum 11 along with the mixture transported inside the first rotating drum 11, thus forming an air circuit, and operating repeatedly.

[0091] Evidently, this embodiment, based on the arrangement of the induced draft assembly 5, can, on the one hand, achieve the efficient utilization of the hot air discharged from the end of the first rotary drum 11, achieving the heating of the phosphogypsum transported into the first rotary drum 11 by the residual heat of the hot air; on the other hand, because the hot air also performs heat exchange by convection with the phosphogypsum during the transport process along the serpentine duct, this is also favorable to improving the heat exchange efficiency inside and outside the first rotary drum 11, improving the dehydration effect of the phosphogypsum.

[0092] In some embodiments, as shown in Figure 3, the induced draft assembly 5 comprises a filtering component 51 and an induced draft fan 52.

[0093] The end of the first rotating drum 11 communicates with the air inlet of the induced draft fan 52 through the filtering component 51, the air outlet of the induced draft fan 52 communicates with the feed chamber.

[0094] Specifically, the end of the first rotary drum 11 communicates with the first end of the first air duct, the second end of the first air duct communicates with the air inlet of the induced draft fan 52, the air outlet of the induced draft fan 52 communicates with the first end of the second air duct, the second end of the second air duct communicates with the feed chamber.

[0095] Under the impulse of the induced draft fan 52, the hot air discharged from the end of the first rotary drum 11 passes successively through the filtering component 51 and the induced draft fan 52, then enters the interior of the rotary kiln 1 through the feed chamber, thus forming an air circuit.

[0096] Where the filtering component 51 is arranged at the first end of the first air duct, the filtering component 51 comprises a filter mesh and a vibrator, the vibrator being connected to the filter mesh. Based on the vibratory action of the vibrator, the accumulation of dust on the filter mesh can be prevented.

[0097] In practical application, the first end of the first air duct can be configured as a trumpet-shaped air inlet. The filter mesh is arranged inside the trumpet-shaped air inlet, and the vibrator is arranged on the side of the filter mesh facing the first rotary drum 11. In this way, when dust accumulates on the filter mesh, activating the vibrator causes the accumulated dust to fall under the vibration of the vibrator, then return to the interior of the first rotary drum 11 along the trumpet-shaped air inlet.

[0098] In some embodiments, as shown in Figures 1, 4 and 6, the induced draft assembly 5 comprises a cyclone separator 53 and an induced draft fan 52; the end of the first rotating drum 11 communicates with the air inlet in the side wall of the cyclone separator 53, the air outlet at the top of the cyclone separator 53 communicates with the air inlet of the induced draft fan 52, the air outlet of the induced draft fan 52 communicates with the feed chamber, the bottom end of the cyclone separator 53 is used to discharge the separated solid waste.

[0099] It is understandable that, under the impulse of the induced draft fan 52, the hot air discharged from the end of the first rotating drum 11 enters radially into the interior of the cyclone cylinder corresponding to the cyclone separator 53, and rotates along the inner wall of the cyclone cylinder. During this process, the large-particle solid waste gradually reaches the lower end of the cyclone separator 53. Discharged from the lower end of the cyclone separator 53, the small-particle dust enters the induced draft fan 52 along with the hot air, then reaches the rotary kiln 1 along the air duct, thus forming an air circuit.

[0100] Evidently, this embodiment, by configuring the cyclone separator 53 or the filtering component 51 in the induced draft assembly 5, can effectively separate solid waste in the hot air during the hot air circulation process, thereby achieving the purification of the phosphogypsum while using the hot air for heating and dehydrating the phosphogypsum.

[0101] In some embodiments, as shown in Figures 1, 3, 4 and 5, the separation component 4 comprises a first discharge channel 41, a separation screen 42, a second discharge channel 43 and a discharge hopper 44.

[0102] The end of the first rotating drum 11 communicates with one end of the first discharge channel 41, the other end of the first discharge channel 41 extends into the screening surface of the separation screen 42.

[0103] The material retained on the screen separated by the separation screen 42 is discharged through the second discharge channel 43, the material passing through the screen separated by the separation screen 42 is discharged through the discharge hopper 44.

[0104] Specifically, the separation screen 42 can be configured to be arranged in an inclined manner, the end of the first rotating drum 11 communicating with the first end of the first discharge channel 41, the second end of the first discharge channel 41 extending inclinedly downwards towards the screening surface of the separation screen 42.

[0105] The first end of the second discharge channel 43 communicates with the outlet end of the material retained on the screen of the separation screen 42, the second discharge channel 43 is arranged inclined downwards, to facilitate the material retained on the screen separated by the separation screen 42 being discharged from the second end of the second discharge channel 43 under the action of its own weight.

[0106] The discharge hopper 44 is arranged on the lower side of the separation screen 42, to receive the material that passes through the screen separated by the separation screen 42, the material that passes through the screen received in the discharge hopper 44 is discharged from the discharge outlet at its lower end.

[0107] Where the material retained on the screen separated by the separation screen 42 shown in this embodiment has as its main component large-granulometry ceramsite particles, the material passing through the screen is generally phosphate gypsum for construction in powder form.

[0108] Finally, it should be noted that: prior embodiments are used only to illustrate the technical solutions of the present invention, not to limit it; although the present invention has been described in detail with reference to prior embodiments, ordinary practitioners in the field should understand that they may still modify the technical solutions recorded in prior embodiments, or make equivalent substitutions of some of their technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention. Industrial Applicability

[0109] The present invention provides a device for the harmless treatment of phosphogypsum by calcination using high-temperature ceramsite, comprising a rotary kiln, a first feeding component, a second feeding component, and a separation component; the rotary kiln comprises a first rotating drum and a second rotating drum; a first intermediate layer channel is formed between the first rotating drum and the second rotating drum, the initial end of the first intermediate layer channel communicating with the initial end of the first rotating drum; the first feeding component is used to introduce high-temperature ceramsite into the interior of the first rotating drum; the second feeding component is used to introduce phosphogypsum into the interior of the first intermediate layer channel;The mixture inside the first rotating drum and the phosphogypsum inside the first intermediate layer channel can exchange heat to dehydrate the phosphogypsum; the separation component is used to separate the mixture discharged from the first rotating drum, obtaining calcined phosphogypsum. The present invention exhibits high calcination and dehydration efficiency of phosphogypsum, enabling the harmless, low-carbon treatment of phosphogypsum to obtain phosphate gypsum for construction, presenting good economic value and application prospects.

Claims

1. A device for the harmless treatment of phosphogypsum by calcination using high-temperature ceramsite, characterized in that it comprises: a rotary kiln, a first feeding component, a second feeding component, and a separation component; said rotary kiln comprises a first rotating drum and a second rotating drum; said second rotating drum is mounted around the outside of said first rotating drum; a first intermediate layer channel is formed between said first rotating drum and said second rotating drum, the initial end of said first intermediate layer channel communicating with the initial end of said first rotating drum; said first feeding component communicating with the initial end of said first rotating drum, for introducing high-temperature ceramsite into the interior of said first rotating drum;said second feed component communicates with said first intermediate layer channel, to introduce phosphogypsum into said first intermediate layer channel; said second rotary drum is used to propel the phosphogypsum along said first intermediate layer channel towards the initial end of said first rotary drum; said first rotary drum is used to propel the mixture composed of phosphogypsum and high-temperature ceramsite from the initial end of said first rotary drum towards the final end; the mixture inside said first rotary drum and the phosphogypsum inside said first intermediate layer channel can exchange heat through the drum wall of said first rotary drum, to perform the dehydration treatment of said phosphogypsum;1. The separation component is arranged at the end of the first rotating drum to separate the mixture discharged from the first rotating drum, obtaining calcined phosphogypsum.

2. The device for the harmless treatment of phosphogypsum by calcination using high-temperature ceramsite according to claim 1, characterized in that the inner wall of the first rotating drum and the inner wall of the second rotating drum are provided with helical feed vanes; wherein the first rotating drum and the second rotating drum can rotate in the same direction at the same speed or at different speeds.

3. The device for the harmless treatment of phosphogypsum by calcination using high-temperature ceramsite according to claim 1, characterized in that the rotary kiln further comprises a kiln head;The furnace head is annular in shape and mounted around the peripheral wall of the second rotating drum. A feeding chamber is formed between the furnace head and the peripheral wall of the second rotating drum. The peripheral wall of the second rotating drum is provided with a communication opening. The feeding chamber communicates with the first intermediate layer channel through this communication opening. The second feeding component connects to the furnace head to introduce the phosphogypsum into the feeding chamber.

4. The device for the harmless treatment of phosphogypsum by calcination using high-temperature ceramsite according to claim 3, characterized in that multiple second rotating drums are provided.Multiple second rotating drums are mounted successively around the outside of the first rotating drum; between each pair of adjacent second rotating drums, a second intermediate layer channel is formed; multiple second intermediate layer channels and the first intermediate layer channel communicate successively end-to-end from the outside to the inside, forming a serpentine conduit; the furnace head is mounted around the peripheral wall of the second rotating drum of the outermost layer; the feed chamber is formed between the furnace head and the second rotating drum of the outermost layer; the peripheral wall of the second rotating drum of the outermost layer is provided with a communication opening; the feed chamber communicates with the serpentine conduit through the communication opening.wherein the phosphogypsum transported by said second feed component can be conveyed along said serpentine conduit, finally reaching the interior of said first rotating drum.

5. The device for the harmless treatment of phosphogypsum by calcination using high-temperature ceramsite according to claim 4, characterized in that, in the case where the number of said second rotating drums is odd, said kiln head is arranged at the end of the second rotating drum of the outermost layer;In the event that the number of said second rotating drums is an even number, said kiln head is arranged at the initial end of the second rotating drum of the outermost layer.

6. The device for the harmless treatment of phosphogypsum by calcination using high-temperature ceramsite according to claim 3, characterized in that a feed mechanism is arranged inside said feed chamber; said feed mechanism is used to propel the phosphogypsum inside said feed chamber through said communication opening into said first intermediate layer channel.

7. The device for the harmless treatment of phosphogypsum by calcination using high-temperature ceramsite according to any of claims 3 to 6, characterized in that it further comprises: an induced draft assembly;One end of said induced draft assembly communicates with the end of said first rotating drum, the other end communicates with said feed chamber; wherein said induced draft assembly is used to propel the hot air discharged from the end of said first rotating drum back into said feed chamber.

8. The device for the harmless treatment of phosphogypsum by calcination using high-temperature ceramsite according to claim 7, characterized in that said induced draft assembly comprises a filtering component and an induced draft fan;The end of said first rotating drum communicates with the air inlet of said induced draft fan through said filtering component, the air outlet of said induced draft fan communicates with said feed chamber.

9. The device for the harmless treatment of phosphogypsum by calcination using high-temperature ceramsite according to claim 7, characterized in that said induced draft assembly comprises a cyclone separator and an induced draft fan;The end of said first rotating drum communicates with the air inlet in the side wall of said cyclone separator, the air outlet at the top of said cyclone separator communicates with the air inlet of said induced draft fan, the air outlet of said induced draft fan communicates with said feed chamber, the lower end of said cyclone separator is used to discharge the separated solid waste.

10. The device for the harmless treatment of phosphogypsum by calcination using high-temperature ceramsite according to any of claims 1 to 6, characterized in that said separation component comprises a first discharge channel, a separation screen, a second discharge channel, and a discharge hopper;The end of said first rotating drum communicates with one end of said first discharge channel, the other end of said first discharge channel extends into the screening surface of said separating screen; the material retained on the screen separated by said separating screen is discharged through said second discharge channel, the material passing through the screen separated by said separating screen is discharged through said discharge hopper.

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