Belt vacuum filter device for non-hazardous treatment of phosphate rock

Abstract

The utility model discloses a belt type vacuum filter device for phosphorite harmless treatment belongs to phosphor gypsum processing technical field. Including belt type vacuum filter, filter residue collection groove, vacuum condensation system, N liquid discharge tanks and N buffer tanks, vacuum condensation system includes condenser, condensing separator, vacuum pump and vacuum pump exhaust separator, and belt type vacuum filter is equipped with N filter washing area, N liquid discharge tanks are connected with N filter washing area respectively, and its exhaust port is connected with vacuum condensation system, and its liquid outlet is connected with N buffer tanks respectively, this belt type vacuum filter device is arranged in two layers, and belt type vacuum filter, liquid discharge tank, condenser and condensing separator are located in the upper layer, and filter residue collection groove, vacuum pump, vacuum pump exhaust separator and buffer tank are located in the lower layer, N liquid discharge tanks, condenser and condensing separator are sequentially arranged from back to front, and N liquid discharge tanks are located at N filter washing area side respectively, and buffer tank is located at the just below of N filter washing area respectively.

Description

Technical Field

[0001] This utility model belongs to the field of phosphogypsum treatment technology, and specifically relates to a belt vacuum filter device for the harmless treatment of phosphate rock. Background Technology

[0002] Phosphogypsum is an industrial byproduct of the production of high-concentration phosphate compound fertilizer. Its main component is calcium sulfate dihydrate (CaSO42H2O). The production of 1 ton of phosphoric acid (calculated as 100% P2O5) produces 4.8-5.0 tons of phosphogypsum, resulting in enormous solid waste pressure. Therefore, timely treatment of phosphogypsum is necessary.

[0003] In existing technologies, belt vacuum filters can be used to process phosphogypsum for washing, dehydration, and dephosphorization. For example, patent application number CN202222150816.5 discloses a filtration device for drying phosphogypsum, including a vacuum condensation system and a belt filter arranged in a front-to-back direction. The lower rear end of the belt filter has a filter cloth washing area, and directly below the filter cloth washing area is a rinsing water collection tank. The filtration device also includes a filtrate drain tank, a first-wash drain tank, a second-wash drain tank, a third-wash drain tank, a filtrate buffer tank, a first-wash buffer tank, a second-wash buffer tank, a third-wash buffer tank, a neutralization tank, a filter press, and a filtrate storage tank. The belt filter is divided into a filtration zone, a first-wash zone, a second-wash zone, and a third-wash zone from front to back. The filtration zone inputs phosphogypsum, and the filtrate buffer tank outputs phosphogypsum return water. The outlet, filtrate drain tank, and filtrate buffer tank of the filtration zone are connected in sequence. The outlet, filtrate drain tank, filtrate buffer tank, neutralization tank, filter press, filtrate storage tank, and inlet of the third washing zone are connected in sequence. The outlet, filtrate drain tank, filtrate buffer tank, and inlet of the first washing zone of the second washing zone are connected in sequence. The outlet, filtrate drain tank, filtrate buffer tank, and inlet of the second washing zone of the third washing zone are connected in sequence. The filtrate drain tank, filtrate drain tank of the first washing zone, filtrate drain tank of the second washing zone, and filtrate buffer tank of the third washing zone are all connected to the vacuum condensation system. The vacuum condensation system includes a condenser, a condensation separator, a vacuum pump, a vacuum pump exhaust separator, a condensation circulation tank, a cooling tower, and a vacuum pump circulation tank. The exhaust ports of the filtrate drain tank, the first wash drain tank, the second wash drain tank, and the third wash drain tank are all connected to the air inlet of the condenser. The air outlet of the condenser, the condensation separator, the vacuum pump, and the vacuum pump exhaust separator are connected in sequence. The drain ports of the condenser and the condensation separator are both connected to the condensation circulation tank. The condensation circulation tank is connected to the water inlet of the cooling tower and the filtrate storage tank. The water outlet of the cooling tower is connected to the liquid inlet of the condensation separator. The circulating water inlet of the vacuum pump is connected to the vacuum pump circulation tank. The vacuum pump circulation tank is connected to the circulating water outlet of the vacuum pump and the drain port of the vacuum pump exhaust separator.

[0004] The structure of a belt filter can be found in patent application number CN202022756396.6, which discloses a horizontal rubber belt vacuum filter, including a frame, a rubber belt, a vacuum box, a filter cloth, several guide rollers, a head roller, a tail roller, and a scraper. The filter is characterized by further including several filtration zones and two rotating mechanisms. The two rotating mechanisms are respectively fixed to both ends of the frame, and the head roller and tail roller are each connected to one of the rotating mechanisms. The several filtration zones are sequentially arranged and fixed on the frame, located between the head roller and tail roller. At least two of the filtration zones include a cloth-feeding unit, at least one of the filtration zones includes a washing unit, and at least one of the filtration zones includes a dewatering unit. Furthermore, the filtration zone closest to the tail roller includes a cloth-feeding unit, and the filtration zone closest to the head roller includes a dewatering unit. At least one washing unit is located between any cloth-feeding unit and any dewatering unit. Each filtration zone includes both a cloth-feeding unit and a washing unit.

[0005] The filtration equipment used for drying phosphogypsum includes not only belt filters, but also multiple drain tanks, multiple buffer tanks, and a complex vacuum condensation system. If all of these are installed on a single plane, they would require a large area, resulting in a large workshop and high costs. Utility Model Content

[0006] This utility model provides a belt vacuum filter for the harmless treatment of phosphate rock, which optimizes the layout of its various structures, reduces floor space, and lowers costs. The technical solution is as follows: This utility model provides a belt vacuum filtration device for the harmless treatment of phosphate rock. The belt vacuum filtration device includes a belt vacuum filter 1, a filter residue collection tank 2, a vacuum condensation system, N drain tanks 3, and N buffer tanks 4. The vacuum condensation system includes a condenser 21, a condensation separator 22, a vacuum pump 23, and a vacuum pump exhaust separator 24. The belt vacuum filter 1 is arranged in a front-to-back direction and is divided into N filter washing zones from front to back. The N drain tanks 3 are respectively connected to the outlets of the N filter washing zones, and their exhaust ports are all connected to the vacuum condensation system via pipelines. Their outlets are also connected to the vacuum condensation system via pipelines. Do not connect to N buffer tanks 4; the belt vacuum filter device is arranged in two layers; the belt vacuum filter 1, drain tank 3, condenser 21 and condenser separator 22 are located in the upper layer 5, and the filter residue collection tank 2, vacuum pump 23, vacuum pump exhaust separator 24 and buffer tank 4 are located in the lower layer 6; the N drain tanks 3, condenser 21 and condenser separator 22 are arranged in sequence from back to front and are arranged side by side with the belt vacuum filter 1. The N drain tanks 3 are located next to the N filter washing areas. The buffer tanks 4 are located directly below the N filter washing areas. The filter residue collection tank 2 is located directly below the rear end of the belt vacuum filter 1.

[0007] Specifically, N is four.

[0008] More specifically, in this embodiment of the present invention, the four drain tanks 3 are respectively a filtrate drain tank, a first-wash drain tank, a second-wash drain tank, and a third-wash drain tank; the four buffer tanks 4 are respectively a filtrate buffer tank, a first-wash buffer tank, a second-wash buffer tank, and a third-wash buffer tank; the four filtration and washing zones are respectively a filtration zone, a first-wash zone, a second-wash zone, and a third-wash zone; the outlets of the filtration zone, the first-wash zone, the second-wash zone, and the third-wash zone are respectively connected to the filtrate drain tank, the first-wash drain tank, the second-wash drain tank, and the third-wash drain tank; the filtrate drain tank, the first-wash drain tank, the second-wash drain tank, and the third-wash drain tank are respectively connected to the filtrate drain tank, the first-wash drain tank, the second-wash drain tank, and the third-wash drain tank; the filtrate drain tank, the first-wash drain tank, the second-wash drain tank, the third ... are respectively connected to the filtrate drain tank, the first-wash drain tank, the second-wash drain tank, and the third-wash drain tank are respectively connected to the filtrate drain tank, the first-wash drain tank, the second-wash drain tank, and the third-wash drain tank are respectively connected to the filtrate drain tank, the first-wash drain tank, the second-wash drain tank, and the third-wash drain tank are respectively connected to the filtrate drain tank, the first-wash drain tank, the second-wash drain tank, and The exhaust ports of the filtrate drain tank, the first wash drain tank, the second wash drain tank, and the third wash drain tank are all connected to the vacuum condensation system via pipelines. The filtrate drain tank, the first wash drain tank, the second wash drain tank, and the third wash drain tank are located next to the filtration zone, the first wash zone, the second wash zone, and the third wash zone, respectively. The filtrate buffer tank, the first wash buffer tank, the second wash buffer tank, and the third wash buffer tank are located directly below the filtration zone, the first wash zone, the second wash zone, and the third wash zone, respectively, and they are connected to the liquid outlets at the bottom of the filtrate drain tank, the first wash drain tank, the second wash drain tank, and the third wash drain tank, respectively, via pipelines.

[0009] The belt vacuum filter 1 in this embodiment includes a frame 11 arranged in the front-to-back direction, a belt 12 arranged in the front-to-back direction on the frame 11, a filter cloth 13 on the frame 11 and located above the belt 12, a pressing structure 14 at the front of the frame 11 for pressing the filter cloth 13 to the front end of the belt 12, a filter cloth washing structure 15 at the rear lower part of the frame 11 for rinsing the filter cloth 13, a scraping structure 16 at the rear of the frame 11 for scraping off the material at the rear end of the filter cloth 13, a tensioning structure 17 at the rear lower part of the frame 11 for tensioning the filter cloth 13, and four vacuum boxes 18 arranged adjacent to each other in the front and back. The four vacuum boxes 18 are located directly below the four filter washing zones. The vacuum boxes 18 are located adjacent to the belt 12 and are arranged in the front-to-back direction on the frame 11. Four drain tanks 3 are located on the left or right side of the four vacuum boxes 18 and are connected to the four vacuum boxes 18 respectively.

[0010] Furthermore, in this embodiment of the present invention, a filtrate main pipe 31 is provided on the left or right side of the vacuum chamber 18; the filtrate main pipe 31 is arranged in the front-to-back direction, and its inner side is connected to the corresponding vacuum chamber 18 through multiple branch pipes arranged in parallel front and back, and its outer middle part is connected to the corresponding drain tank 3 through a pipeline, and it is fixed to the left or right side of the frame 11 by a bracket; the filtrate main pipes 31 of the four vacuum chambers 18 are arranged adjacent to each other in sequence.

[0011] Specifically, in this embodiment of the present invention, the condenser 21 and the condenser separator 22 are located next to the front of the belt vacuum filter 1. The outlets at the bottom of the filtrate drain tank, the first wash drain tank and the second wash drain tank are connected to the condenser 21 through the same front-to-back drain manifold 32. The condenser 21, the condenser separator 22, the vacuum pump 23 and the vacuum pump exhaust separator 24 are connected in sequence through pipelines. The third wash drain tank is connected to the vacuum pump 23 through a pipeline. The vacuum pump 23 is located below the front of the belt vacuum filter 1.

[0012] More specifically, in this embodiment of the invention, the condenser separator 22 is located in front of and above the condenser 21.

[0013] Furthermore, in this embodiment of the utility model, the belt vacuum filter 1 is provided with a slurry distributor 19, three washing liquid distributors 110 and five weirs 111. The five weirs 111 are arranged alternately with the four filtration and washing zones. The slurry distributor 19 is provided above the front part of the filtration zone. The washing liquid distributors 110 are provided above the front part of the first washing zone, the second washing zone and the third washing zone. The slurry distributor 19, the three washing liquid distributors 110 and the five weirs 111 are all arranged on the frame 11 in the left and right direction and are all located directly above the filter cloth 13.

[0014] Furthermore, in this embodiment of the present invention, the upper layer 5, located directly below the belt vacuum filter 1, is provided with a wastewater collection ditch 7, which is arranged in the front-to-back direction; the lower layer 6 is provided with a wastewater collection tank 8, which is a ground tank and is connected to the wastewater collection ditch 7 through a pipeline. The beneficial effects of the technical solution provided by this utility model embodiment are as follows: This utility model embodiment provides a belt vacuum filter for the harmless treatment of phosphate rock, which optimizes the layout of each structure, adopts a double-layer design, reduces the footprint, facilitates pipeline routing and installation, and reduces costs. It is applicable to scenarios with multiple belt vacuum filters. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the belt vacuum filter device for harmless treatment of phosphate rock provided by this utility model; Figure 2 This is a structural diagram of a combination of a belt vacuum filter, a drain tank, a condenser, and a condenser separator. Figure 3 This is a cross-sectional view of the belt vacuum filter device for harmless treatment of phosphate rock provided by this utility model; Figure 4 This is a schematic diagram of a belt vacuum filter. Figure 5 This is a cross-sectional view of a belt vacuum filter.

[0016] In the diagram: 1. Belt vacuum filter, 2. Filter residue collection tank, 3. Drainage tank, 4. Buffer tank, 5. Upper layer, 6. Lower layer, 7. Wastewater collection ditch, 8. Wastewater collection tank; 11 Frame, 12 Belt, 13 Filter cloth, 14 Pressing structure, 15 Filter cloth washing structure, 16 Scraping structure, 17 Tensioning structure, 18 Vacuum box, 19 Slurry distributor, 110 Washing liquid distributor, 111 Weir. 21 Condenser, 22 Condenser Separator, 23 Vacuum Pump, 24 Vacuum Pump Exhaust Separator; 31 Filtration main pipe, 32 Drainage main pipe. Detailed Implementation

[0017] To make the objectives, technical solutions and advantages of this utility model clearer, the utility model will be described in further detail below with reference to the accompanying drawings.

[0018] Example 1 See Figure 1-5 Example 1 provides a belt vacuum filter device for the harmless treatment of phosphate rock. The device includes a belt vacuum filter 1, a filter residue collection tank 2, a vacuum condensation system, a wastewater collection ditch 7, a wastewater collection tank 8, N drainage tanks 3 and N buffer tanks 4, etc.

[0019] The vacuum condensation system includes a condenser 21, a condensation separator 22, a vacuum pump 23, and a vacuum pump exhaust separator 24. The belt vacuum filter 1 is arranged longitudinally and is divided into N filter washing zones (specifically, one filter zone and N1-1 wash zones) from front to back. N drain tanks 3 are connected to the outlets of the N filter washing zones, and their exhaust ports are connected to the vacuum condensation system (condenser 21 or vacuum pump 23, etc.) via pipelines. Their outlets are also connected to N buffer tanks 4 via pipelines. For details on the belt vacuum filter 1 and the vacuum condensation system, please refer to the description in application number CN202022756396.6.

[0020] The belt vacuum filter unit is arranged in two layers. The belt vacuum filter 1, drain tank 3, condenser 21, condenser separator 22, and wastewater collection ditch 7 are located in the upper layer 5. The filter residue collection tank 2, vacuum pump 23, vacuum pump exhaust separator 24, buffer tank 4, and wastewater collection tank 8 are located in the lower layer 6. N drain tanks 3, condensers 21, and condenser separators 22 are arranged sequentially from back to front, parallel to the belt vacuum filter 1. The N drain tanks 3 are located next to the N filter washing zones, the buffer tanks 4 are located directly below the N filter washing zones, and the filter residue collection tank 2 is located directly below the rear end of the belt vacuum filter 1. The wastewater collection ditch 7 is arranged along the front-to-back direction, located directly below the belt vacuum filter 1, and is used to collect wastewater. The wastewater collection tank 8 is a ground-level tank connected to the wastewater collection ditch 7 via pipelines, and is used to temporarily store wastewater.

[0021] Example 2 See Figure 1-5 Example 1 provides a belt vacuum filter device for the harmless treatment of phosphate rock. Its structure is basically the same as that of Example 1, except that the belt vacuum filter 1 in this example includes a frame 11, a belt 12, a filter cloth 13, a pressing structure 14, a filter cloth washing structure 15, a scraping structure 16, a tensioning structure 17, a slurry distributor 19, three washing liquid distributors 110, five weirs 111, and four vacuum boxes 18, etc., and its structure is similar to that of the prior art.

[0022] The frame 11 is arranged in a front-to-back direction and is located on the upper layer 5. The conveyor belt 12 is arranged in a front-to-back direction on the frame 11 and has a ring structure. The filter cloth 13 is arranged in a front-to-back direction on the frame 11, located above the conveyor belt 12, and also has a ring structure, divided into four filter washing zones from front to back. Correspondingly, there are four drain tanks 3 and four buffer tanks 4. A pressing structure 14 is located at the front of the frame 11 and is used to press the filter belt 13 tightly against the front end of the conveyor belt 12. A filter cloth washing structure 15 is located at the lower rear of the frame 11 and is used to wash the filter cloth 13. A scraping structure 16 is located at the rear end of the frame 11 and is used to scrape off the material at the rear end of the filter cloth 13 (which falls into the filter residue collection tank 2). A tensioning structure 17 is located at the lower rear of the frame 11 and is used to tension the filter cloth 13.

[0023] Four vacuum chambers 18 are located directly below the four filtration and washing zones, arranged adjacent to each other. The vacuum chambers 18 are positioned adjacent to and below the conveyor belt 12, mounted on the frame 11 in a front-to-back direction, with open tops, and are specifically rectangular trough structures. Four drain tanks 3 are located to the left or right of the four vacuum chambers 18 and are connected to each vacuum chamber 18. Specifically, the four drain tanks 3 are filtrate drain tanks, first-wash drain tanks, second-wash drain tanks, and third-wash drain tanks, respectively, and the four buffer tanks 4 are filtrate buffer tanks, first-wash buffer tanks, second-wash buffer tanks, and third-wash buffer tanks, respectively. The four filtration and washing zones are the filtration zone, first-wash zone, second-wash zone, and third-wash zone. A vacuum chamber 18 is positioned directly below each of the filtration zone, first-wash zone, second-wash zone, and third-wash zone, and the outlets of the vacuum chambers 18 directly below the filtration zone, first-wash zone, second-wash zone, and third-wash zone are connected to the filtrate drain tank, first-wash drain tank, second-wash drain tank, and third-wash drain tank, respectively, via pipelines. The vents of the filtrate drain tank, the first wash drain tank, the second wash drain tank, and the third wash drain tank are all connected to the vacuum condensation system via pipelines. The filtrate drain tank, the first wash drain tank, the second wash drain tank, and the third wash drain tank are located beside (to the left or right) the filtration zone, the first wash zone, the second wash zone, and the third wash zone, respectively. The filtrate buffer tank, the first wash buffer tank, the second wash buffer tank, and the third wash buffer tank are located directly below the filtration zone, the first wash zone, the second wash zone, and the third wash zone, respectively, and are connected to the outlets at the bottom of the filtrate drain tank, the first wash drain tank, the second wash drain tank, and the third wash drain tank, respectively, via pipelines. The condenser separator 22 is located in front of and above the condenser 21. Five weirs 111 are arranged alternately with four filtration and washing zones. A slurry distributor 19 is provided above the front of the filtration zone for discharging phosphogypsum. Washing liquid distributors 110 are provided above the front of the first, second, and third washing zones for discharging washing liquid. The slurry distributor 19, the three washing liquid distributors 110, and the five weirs 111 are all arranged on the frame 11 in the left-right direction and are all located directly above the filter cloth 13.

[0024] Example 3 See Figure 2 Example 3 provides a belt vacuum filter device for the harmless treatment of phosphate rock. Its structure is basically the same as that of Example 2, except that the four drain tanks 3, condenser 21 and condenser separator 22 in this example are arranged in sequence from back to front and are located on the right side of the belt vacuum filter 1.

[0025] Example 4 See Figure 1-5Example 4 provides a belt vacuum filtration device for the harmless treatment of phosphate rock. Its structure is basically the same as that of Example 3, except that: in this example, a filtrate main pipe 31 is provided on the left or right side (specifically the right side) of the vacuum chamber 18. The filtrate main pipe 31 is arranged in a front-to-back direction, and its inner side is connected to the corresponding vacuum chamber 18 through multiple branch pipes arranged side-by-side (in a left-to-right direction). Its outer middle part is connected to the corresponding drain tank 3 through a pipeline. It is fixed to the left or right side of the frame 11 by a bracket, and its front and rear ends are closed. The filtrate main pipes 31 of the four vacuum chambers 18 are arranged adjacent to each other in sequence.

[0026] Example 5 See Figure 3 Example 5 provides a belt vacuum filter device for the harmless treatment of phosphate rock. Its structure is basically the same as that of Example 1, except that: in this example, there are two belt vacuum filters 1, which are arranged side by side. The drain tank 3, condenser 21 and condenser separator 22 are located between the two belt vacuum filters 1. The two belt vacuum filters 1 share a wastewater collection tank 8, vacuum pump 23 and vacuum pump exhaust separator 24.

[0027] Example 6 Example 6 provides a belt vacuum filter device for the harmless treatment of phosphate rock. Its structure is basically the same as that of Example 1, except that the belt vacuum filter 1 in this example is 34m long and 5.3m wide. The distance between the bottom and top of the lower layer 6 is 11m, and the distance between the bottom and top of the upper layer 5 is 10m. Through holes are provided at corresponding positions in the upper layer 5.

[0028] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A belt vacuum filtration device for the harmless treatment of phosphate rock, comprising a belt vacuum filter (1), a filter residue collection tank (2), a vacuum condensation system, N drain tanks (3) and N buffer tanks (4); the vacuum condensation system comprises a condenser (21), a condensation separator (22), a vacuum pump (23) and a vacuum pump exhaust separator (24); the belt vacuum filter (1) is arranged in a front-to-back direction and is divided into N filter washing zones from front to back; the N drain tanks (3) are respectively connected to the outlets of the N filter washing zones, and their exhaust ports are all connected to the vacuum condensation system through pipelines, and their outlets are respectively connected to the N buffer tanks (4) through pipelines; characterized in that, The belt vacuum filter device is arranged in two layers; the belt vacuum filter (1), drain tank (3), condenser (21) and condensation separator (22) are located in the upper layer (5), and the filter residue collection tank (2), vacuum pump (23), vacuum pump exhaust separator (24) and buffer tank (4) are located in the lower layer (6); N drain tanks (3), condenser (21) and condensation separator (22) are arranged in sequence from back to front and are arranged side by side with the belt vacuum filter (1). The N drain tanks (3) are located next to the N filter washing areas respectively. The buffer tank (4) is located directly below the N filter washing areas respectively. The filter residue collection tank (2) is located directly below the rear end of the belt vacuum filter (1).

2. The belt vacuum filtration device for harmless treatment of phosphate rock according to claim 1, characterized in that, The value of N is four.

3. The belt vacuum filtration device for harmless treatment of phosphate rock according to claim 2, characterized in that, The four drain tanks (3) are respectively the filtrate drain tank, the first wash drain tank, the second wash drain tank, and the third wash drain tank; the four buffer tanks (4) are respectively the filtrate buffer tank, the first wash buffer tank, the second wash buffer tank, and the third wash buffer tank; the four filtration and washing zones are respectively the filtration zone, the first wash zone, the second wash zone, and the third wash zone; the outlets of the filtration zone, the first wash zone, the second wash zone, and the third wash zone are respectively connected to the filtrate drain tank, the first wash drain tank, the second wash drain tank, and the third wash drain tank; the filtrate drain tank, the first wash drain tank, the second wash drain tank, the second wash drain tank, the third wash drain tank, the fourth wash buffer tank, the fifth wash buffer tank, the sixth wash buffer tank, the seventh wash buffer tank, the eighth wash buffer tank, the ninth wash buffer tank, the eleventh ... The exhaust ports of the liquid tank and the third wash drain tank are connected to the vacuum condensation system via pipelines. The filtrate drain tank, the first wash drain tank, the second wash drain tank, and the third wash drain tank are located next to the filtration zone, the first wash zone, the second wash zone, and the third wash zone, respectively. The filtrate buffer tank, the first wash buffer tank, the second wash buffer tank, and the third wash buffer tank are located directly below the filtration zone, the first wash zone, the second wash zone, and the third wash zone, respectively, and are connected to the liquid outlets at the bottom of the filtrate drain tank, the first wash drain tank, the second wash drain tank, and the third wash drain tank, respectively, via pipelines.

4. The belt vacuum filtration device for harmless treatment of phosphate rock according to claim 3, characterized in that, The belt vacuum filter (1) includes a frame (11) arranged in the front-to-back direction, a belt (12) arranged in the front-to-back direction on the frame (11), a filter cloth (13) on the frame (11) and located above the belt (12), a pressing structure (14) at the front of the frame (11) for pressing the filter cloth (13) to the front end of the belt (12), a filter cloth washing structure (15) at the lower rear of the frame (11) for rinsing the filter cloth (13), and a scraping structure at the rear of the frame (11) for scraping the filter cloth (13). The back-end material scraping structure (16), the lower rear part of the frame (11) and the tensioning structure (17) for tensioning the filter cloth (13) and four vacuum boxes (18) arranged in front and behind, the four vacuum boxes (18) are respectively located directly below the four filter washing areas, the vacuum boxes (18) are located adjacent to the tape (12) and are arranged on the frame (11) in the front and back direction, and the four drain tanks (3) are respectively located on the left or right side of the four vacuum boxes (18) and are respectively connected to the four vacuum boxes (18).

5. The belt vacuum filtration device for harmless treatment of phosphate rock according to claim 4, characterized in that, The vacuum chamber (18) is provided with a filtrate main pipe (31) on the left or right side; the filtrate main pipe (31) is arranged in the front-to-back direction, and its inner side is connected to the corresponding vacuum chamber (18) through multiple branch pipes arranged in the front and back, and its outer middle part is connected to the corresponding drain tank (3) through a pipeline, and it is fixed to the left or right side of the frame (11) by a bracket; the filtrate main pipes (31) of the four vacuum chambers (18) are arranged adjacent to each other in sequence.

6. The belt vacuum filtration device for harmless treatment of phosphate rock according to claim 3, characterized in that, The condenser (21) and condenser separator (22) are located at the front of the belt vacuum filter (1). The outlets at the bottom of the filtrate drain tank, the first wash drain tank and the second wash drain tank are connected to the condenser (21) through the same front-to-back drain manifold (32). The condenser (21), condenser separator (22), vacuum pump (23) and vacuum pump exhaust separator (24) are connected in sequence through pipelines. The third wash drain tank is connected to the vacuum pump (23) through pipelines. The vacuum pump (23) is located below the front of the belt vacuum filter (1).

7. The belt vacuum filtration device for harmless treatment of phosphate rock according to claim 6, characterized in that, The condenser separator (22) is located in front of and above the condenser (21).

8. The belt vacuum filtration device for harmless treatment of phosphate rock according to claim 4, characterized in that, The belt vacuum filter (1) is equipped with a slurry distributor (19), three washing liquid distributors (110) and five weirs (111). The five weirs (111) are arranged alternately with the four filter washing zones. The slurry distributor (19) is located above the front of the filter zone. The washing liquid distributors (110) are located above the front of the first washing zone, the second washing zone and the third washing zone. The slurry distributor (19), the three washing liquid distributors (110) and the five weirs (111) are all arranged on the frame (11) in the left and right direction and are all located directly above the filter cloth (13).

9. The belt vacuum filtration device for harmless treatment of phosphate rock according to claim 1, characterized in that, The upper layer (5) and located directly below the belt vacuum filter (1) is provided with a wastewater collection ditch (7), which is arranged in the front-to-back direction; the lower layer (6) is provided with a wastewater collection tank (8), which is a ground tank and is connected to the wastewater collection ditch (7) through a pipeline.

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