Phosphate ore flotation system capable of removing organic matter

Abstract

The utility model discloses a phosphorus ore flotation system that can remove organic matter belongs to the technical field of wet-process phosphoric acid. The system includes ore pulp storage tank, primary mixer, primary pre -decomposition groove, secondary mixer, secondary pre -decomposition groove, filter press, filtrate collection groove, flotation column, tailing pulp buffer groove, thickener, tailing overflow buffer groove and concentrate pulp storage tank, and the tailing outlet of flotation column is connected with tailing pulp buffer groove. The feed inlet of thickener is connected with tailing pulp buffer groove, and its clear liquid outlet is connected with tailing overflow buffer groove. The ore pulp storage tank, primary mixer, primary pre -decomposition groove, secondary mixer, secondary pre -decomposition groove, flotation column and concentrate pulp storage tank are connected in turn. The tailing overflow buffer groove, filter press, filtrate collection groove and primary pre -decomposition groove are connected in turn, and the underflow outlet of thickener is connected with secondary pre -decomposition groove. The feed inlets of primary mixer and secondary mixer are also connected with the counter acid storage tank and concentrated sulfuric acid storage tank of phosphoric acid extraction device.

Description

Technical Field

[0001] This invention belongs to the field of wet phosphoric acid technology, and specifically relates to a phosphate rock flotation system capable of removing organic matter. Background Technology

[0002] Phosphorus is an essential element for crops. With the development of science and technology, the uses of phosphorus are constantly expanding. Phosphate rock resources are an important basic raw material for the development of the phosphate chemical industry. The main mineral components of phosphate rock are collophane and microcrystalline apatite, with minor minerals including quartz, dolomite, calcite and feldspar fragments, carbonaceous mudstone, and a small amount of glauconite. Phosphate rock is mainly used to produce phosphoric acid. Phosphoric acid, as an intermediate product for final chemical products or other phosphate chemical products, plays a significant role in the development of the national economy. This is mainly reflected in the following two aspects: First, it is used in the production of various fertilizers, such as monoammonium phosphate, diammonium phosphate, and superphosphate. Second, as a chemical intermediate product, it is used in the production of high-value-added fine phosphate chemical products, such as pharmaceutical-grade phosphates, food-grade phosphoric acid, electronic-grade phosphoric acid, phosphate optoelectronic materials, water softeners, and buffers for acid-based detergents.

[0003] The preparation process of wet-process phosphoric acid is as follows: phosphate rock is crushed, ball-milled and thickened to obtain phosphate rock slurry. The phosphate rock slurry is then floated to obtain concentrate slurry. The concentrate slurry is reacted with concentrated sulfuric acid and back acid to obtain reaction solution. The reaction solution is then vacuum filtered to obtain wet-process phosphoric acid, back acid and phosphogypsum.

[0004] For example, patent application number CN201910851385.5 discloses a wet-process phosphoric acid production method. The method includes: reacting a slurry with back acid from a filtration device; reacting the slurry with concentrated sulfuric acid after the reaction; and finally filtering the slurry through a filtration device to obtain phosphoric acid, back acid, and phosphogypsum. The phosphogypsum is then treated in a phosphogypsum wastewater treatment system to obtain phosphogypsum wastewater. The washing liquid in the first washing zone and the filtrate in the initial filtration zone of the filtration device are back acid. The phosphogypsum wastewater is neutralized after heat exchange with the atmospheric condenser of the filtration device. After reaction, sedimentation, pressure filtration, and heating, the solution is sent to the third washing zone of the filtration device as the third washing water. The atmospheric condenser collects the gas from the phosphoric acid separator, filter washing liquid separator, second washing liquid separator, and third washing liquid separator and condenses it to obtain condensate. The condensate is sent to the filter cloth regeneration zone of the filtration device as the filter cloth regeneration water. Sulfuric acid is added to the washing liquid in the third washing zone and adjusted to a sulfuric acid mass concentration of 5.5-6.0% before being sent to the second washing zone of the filtration device as the second washing water. The washing liquid in the filter cloth regeneration zone is combined with the washing liquid in the second washing zone and sent to the first washing zone as the first washing water.

[0005] Phosphate slurry needs to be floated to remove impurities before reacting with concentrated sulfuric acid. Current technology primarily uses flotation for magnesium removal. Existing technologies can utilize flotation cells or flotation columns for flotation.

[0006] For example, patent application number CN202510582645.9 discloses a beneficiation method for high-quality phosphate rock slurry used in the production of hemihydrate-dihydrate phosphoric acid, including the following steps: S1. After preliminary crushing of medium- and low-grade collophane ore, wet grinding and classification are performed to obtain flotation slurry with a concentration of 22-25% and a fineness of 75%-80% (-200 mesh).

[0007] S2. The flotation slurry is pumped into the first slurry mixing tank, and sulfuric acid is added at 11-13 kg / t. Then, it is pumped into the second slurry mixing tank, and reverse flotation collector is added at 0.5-0.65 kg / t. After stirring and conditioning the slurry and mineralizing it, it is pumped into the roughing flotation column for roughing to obtain roughing concentrate. The top overflow enters the scavenging section.

[0008] S3. The roughing concentrate is slurryed to obtain a slurry with a concentration of 24-27% and a pH of 4.3-4.5. The slurry is then pumped into a hydrocyclone group for hydrocyclone classification to obtain a slurry with sesquioxide R2O3 reduced to 1.7-2.0%.

[0009] S4. The slurry is prepared to obtain a slurry with a concentration of 24-27% and a pH of 4.3-4.5. This slurry is then pumped into the fine flotation column to obtain fine phosphate slurry. The top overflow is then fed into the scavenging column.

[0010] S5. The selected slurry is concentrated by a thickener to obtain a high-quality phosphate slurry with a concentration of 64-66%. After pressure filtration, the moisture content is reduced to ≤15%, and the slurry is supplied to the hemihydrate-dihydrate phosphoric acid unit.

[0011] For example, patent application number CN202421906152.3 discloses a phosphate rock flotation system for producing multi-quality phosphate concentrate, including a ball mill. The output end of the ball mill is connected to a first flotation column. A flotation machine is connected to one side of the top of the first flotation column, and a concentrate thickener is connected to one side of the bottom of the first flotation column. A backsweeping conveying pipe is connected to one side of the bottom of the flotation machine. A buffer tank is connected to the other side of the bottom of the first flotation column. A slurry pump is installed at the output end of the buffer tank. The output end of the slurry pump is connected to a second flotation column through a slurry conveying pipe. A middlings conveying pipe is connected to one side of the top of the second flotation column, and a hydrocyclone is connected to one side of the bottom of the second flotation column. An overflow slurry pipe is connected to the upper part of one side of the hydrocyclone.

[0012] For example, patent application number CN202110992216.0 discloses a flotation method for high-magnesium phosphate ore containing mud, the steps of which are as follows: (1) Washing the raw ore of high magnesium phosphate containing mud is used to obtain fine-grained mud phosphate ore and coarse-grained phosphate ore.

[0013] (2) Fine-grained muddy phosphate ore is subjected to flotation column flotation to obtain the first concentrate and muddy tailings.

[0014] (3) Coarse-grained phosphate rock is ground and re-selected to obtain high-grade phosphate concentrate with MgO content of less than 1.0%.

[0015] The main purpose of existing flotation methods is to remove magnesium, typically reducing the MgO content to less than 2%. However, some phosphate rocks have high organic matter content (especially imported phosphate rocks), and the organic matter content of the prepared phosphoric acid can be as high as 3000 pp, which affects the subsequent preparation of ammonium phosphate (such as industrial ammonium phosphate). Utility Model Content

[0016] This invention provides a phosphate rock flotation system capable of removing organic matter, reducing the organic matter content while removing magnesium. The technical solution is as follows: This utility model provides a phosphate rock flotation system capable of removing organic matter. The system includes a slurry storage tank, a flotation column, a tailings slurry buffer tank 11, a thickener 12, a tailings overflow buffer tank 13, and a concentrate slurry storage tank. The tailings outlet of the flotation column is connected to the tailings slurry buffer tank 11 via a pipeline. The feed inlet of the thickener 12 is connected to the tailings slurry buffer tank 11 via a pipeline, and its clarified liquid outlet is connected to the tailings overflow buffer tank 13 via a pipeline. The system also includes a primary mixer 1, a primary pre-decomposition tank 2, a secondary mixer 3, and a secondary pre-decomposition tank 4. The filter press 14 and the filtrate collection tank 15, the slurry storage tank, the primary mixer 1, the primary pre-decomposition tank 2, the secondary mixer 3, the secondary pre-decomposition tank 4, the flotation column and the concentrate slurry storage tank are connected in sequence by pipelines; the tailings overflow buffer tank 13, the filter press 14, the filtrate collection tank 15 and the primary pre-decomposition tank 2 are connected in sequence by pipelines; the underflow outlet of the thickener 12 is connected to the secondary pre-decomposition tank 4 by pipelines; the feed inlets of the primary mixer 1 and the secondary mixer 3 are also connected to the back acid storage tank and the concentrated sulfuric acid storage tank of the phosphoric acid extraction unit by pipelines.

[0017] Preferably, the flotation column in this embodiment of the present invention includes a primary flotation column 5, a rougher ore slurry tank 6, a secondary flotation column 7, a primary cleaner ore slurry tank 8, a tertiary flotation column 9, and a secondary cleaner ore slurry tank 10. The secondary pre-decomposition tank 4, the primary flotation column 5, the rougher ore slurry tank 6, the secondary flotation column 7, the primary cleaner ore slurry tank 8, the tertiary flotation column 9, the secondary cleaner ore slurry tank 10, and the concentrate slurry storage tank are connected sequentially by pipelines. The tailings outlets of the primary flotation column 5 and the secondary flotation column 7 are connected to the tailings slurry buffer tank 11 by pipelines. The tailings outlet of the tertiary flotation column 9 is connected to the rougher ore slurry tank 6 by pipelines. The rougher ore slurry tank 6 is also connected to the flotation reagent supply device by pipelines.

[0018] Furthermore, in this embodiment of the invention, the wastewater outlets of the primary flotation column 5, the secondary flotation column 7, and the tertiary flotation column 9 are all connected to the primary pre-decomposition tank 2 via pipelines.

[0019] Specifically, in this embodiment of the present invention, the roughing ore slurry tank 6 is lower than the primary flotation column 5 and the secondary flotation column 7, and it is connected to the feed inlet of the secondary flotation column 7 through a pipeline with pump 23. The primary cleaning ore slurry tank 8 is lower than the secondary flotation column 7 and the tertiary flotation column 9, and it is connected to the feed inlet of the tertiary flotation column 9 through a pipeline with pump 24. The secondary cleaning ore slurry tank 10 is lower than the tertiary flotation column 9, and it is connected to the concentrate slurry storage tank through a pipeline with pump 25. The inlets of pumps 23, 24, and 25 are also connected to the process water tank through pipelines.

[0020] Furthermore, the phosphate rock flotation system capable of removing organic matter in this embodiment of the present invention also includes a ground tank 16. The overflow ports of the primary pre-decomposition tank 2, the secondary pre-decomposition tank 4, the rougher slurry tank 6, the primary cleaner slurry tank 8, the secondary cleaner slurry tank 10, the tailings slurry buffer tank 11, and the tailings overflow buffer tank 13 are all connected to the ground tank 16 through pipelines. The ground tank 16 is connected to the feed port of the thickener 12 through a pipeline with a pump 28.

[0021] In this embodiment of the present invention, a stirrer is provided in the slurry storage tank, the primary pre-decomposition tank 2, the secondary pre-decomposition tank 4, the roughing slurry tank 6, the primary cleaning slurry tank 8, the secondary cleaning slurry tank 10, the tailings slurry buffer tank 11, the tailings overflow buffer tank 13, and the concentrate slurry storage tank.

[0022] Specifically, in this embodiment of the present invention, the primary mixer 1 and the secondary mixer 3 are both SK-type static mixers with a diameter of 219mm and a length of 1500mm; the primary flotation column 5, the secondary flotation column 7 and the tertiary flotation column 9 are the same and have a diameter of 4.2m and a height of 10m; the primary pre-decomposition tank 2 and the secondary pre-decomposition tank 4 have a diameter of 5m and a height of 7m.

[0023] The beneficial effects of the technical solution provided by this utility model embodiment are: First, it can reduce the amount of defoamer needed; Second, it can reduce the content of insoluble phosphorus in phosphogypsum; Third, it can reduce the content of organic matter. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the principle of the phosphate rock flotation system for removing organic matter provided by this utility model; Figure 2 This is the PID diagram of the pre-decomposed process; Figure 3 This is the PID diagram for the flotation process; Figure 4 This is a PID diagram for tailings treatment; Figure 5 This is the PID diagram for pressure filtration. Figure 6 This is a PID diagram for wastewater treatment.

[0025] In the diagram: 1 Primary mixer, 2 Primary pre-decomposition tank, 3 Secondary mixer, 4 Secondary pre-decomposition tank, 5 Primary flotation column, 6 Rougher slurry tank, 7 Secondary flotation column, 8 Primary cleaner slurry tank, 9 Tertiary flotation column, 10 Secondary cleaner slurry tank, 11 Tailings slurry buffer tank, 12 Thickener, 13 Tailings overflow buffer tank, 14 Filter press, 15 Filtrate collection tank, 16 Ground tank; Pump 1, 22 Pump 2, 23 Pump 3, 24 Pump 4, 25 Pump 5, 26 Pump 6, 27 Pump 7, 28 Pump 8. Detailed Implementation

[0026] 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.

[0027] Example 1 See Figure 1-6Example 1 provides a phosphate rock flotation system capable of removing organic matter. The system includes a slurry storage tank (for storing untreated phosphate slurry), a primary mixer 1, a primary pre-decomposition tank 2, a secondary mixer 3, a secondary pre-decomposition tank 4, a primary flotation column 5 (for flotation), a rougher slurry tank 6 (for temporarily storing the flotated slurry and reacting with flotation reagents), a secondary flotation column 7 (for flotation), a primary cleaner slurry tank 8 (for temporarily storing the flotated slurry), a tertiary flotation column 9 (for flotation), and a secondary cleaner slurry tank 10 (for temporarily storing the flotation slurry). The system includes a slurry storage tank, a tailings slurry buffer tank 11 (for temporary tailings storage), a thickener 12 (for thickening), a tailings overflow buffer tank 13 (for temporary storage of the thickened clear liquid (containing a large amount of foam and scum)), a concentrate slurry storage tank (for storing the treated phosphate slurry, which is then output to the extraction tank of the phosphoric acid extraction unit (see the descriptions in application numbers 202211339827.6 and 202011198890.3 for details)), a filter press 14 (for pressing and filtering the clear liquid), and a filtrate collection tank 15 (for temporary storage of the filtrate), etc. The slurry storage tank, primary mixer 1, primary pre-decomposition tank 2, secondary mixer 3, secondary pre-decomposition tank 4, primary flotation column 5, rougher slurry tank 6, secondary flotation column 7, primary cleaner slurry tank 8, tertiary flotation column 9, secondary cleaner slurry tank 10, and concentrate slurry storage tank are sequentially connected by pipelines to achieve slurry treatment (including removal of organic matter and magnesium, etc.). The feed inlets of both the primary mixer 1 and the secondary mixer 3 are connected via pipelines to the back acid storage tank (from the first washing zone and primary filtration zone of the rotary vacuum filter, with a phosphoric acid concentration of 14-16% for back acid, see application number CN201910851385.5) and the concentrated sulfuric acid storage tank (for supplying concentrated sulfuric acid, see application number CN201910851385.5) of the phosphoric acid extraction unit. The amount of back acid added is 3-8% of the weight of the phosphate rock, and the amount of concentrated sulfuric acid is 0.5-3.0% of the weight of the phosphate rock. The amounts of back acid and concentrated sulfuric acid in the extraction tank are appropriately reduced. The roughing slurry tank 6 is also connected via pipelines to the flotation reagent supply device (for supplying flotation reagents, including collectors and frothers, consistent with the prior art). The tailings outlets of the primary flotation column 5 and the secondary flotation column 7 are connected to the feed inlet of the tailings slurry buffer tank 11 via pipelines. The tailings outlet of the tertiary flotation column 9 is connected to the feed inlet of the roughing ore slurry tank 6 via pipelines. The feed inlet of the thickener 12 is connected to the discharge outlet of the tailings slurry buffer tank 11 via pipelines. Its upper clear liquid outlet is connected to the tailings overflow buffer tank 13 via pipelines (outputting clear liquid containing a large amount of foam and scum). Its bottom underflow outlet is connected to the feed inlet of the secondary pre-decomposition tank 4 via pipelines to further treat and float the underflow. The discharge outlet of the tailings overflow buffer tank 13, the filter press 14 (outputting filtrate to the filtrate collection tank 15), the filtrate collection tank 15, and the feed inlet of the primary pre-decomposition tank 2 are connected sequentially via pipelines.

[0028] In this embodiment of the present invention, a stirrer is provided in the slurry storage tank, the primary pre-decomposition tank 2, the secondary pre-decomposition tank 4, the roughing slurry tank 6, the primary cleaning slurry tank 8, the secondary cleaning slurry tank 10, the tailings slurry buffer tank 11, the tailings overflow buffer tank 13, and the concentrate slurry storage tank.

[0029] Example 2 See Figure 3 Example 2 provides a phosphate rock flotation system capable of removing organic matter. Its structure is basically the same as that of Example 1, except that the wastewater outlets (such as washing wastewater) of the primary flotation column 5, the secondary flotation column 7 and the tertiary flotation column 9 in this example are all connected to the primary pre-decomposition tank 2 via pipelines.

[0030] Example 3 See Figure 6 Example 3 provides a phosphate rock flotation system capable of removing organic matter, the structure of which is basically the same as that of Example 1. The difference is that the phosphate rock flotation system capable of removing organic matter in this example also includes a ground tank 16. The overflow ports (located on the upper part of the corresponding structure) of the primary pre-decomposition tank 2, secondary pre-decomposition tank 4, rougher slurry tank 6, primary cleaner slurry tank 8, secondary cleaner slurry tank 10, tailings slurry buffer tank 11 and tailings overflow buffer tank 13 are all connected to the ground tank 16 through pipelines. The ground tank 16 is connected to the feed port of the thickener 12 through a pipeline with a pump 28.

[0031] Example 4 See Figure 2-5Example 4 provides a phosphate rock flotation system capable of removing organic matter. Its structure is basically the same as that of Example 4, except that: in this example, the outlet of the primary pre-decomposition tank 2 is connected to the inlet of the secondary mixer 3 through a pipeline with pump 21, and the outlet of the secondary pre-decomposition tank 4 is connected to the inlet of the primary flotation column 5 through a pipeline with pump 22. The roughing ore slurry tank 6 is lower than the primary flotation column 5 and the secondary flotation column 7, and is connected to the feed inlet of the secondary flotation column 7 via a pipeline with pump 23. The primary cleaning ore slurry tank 8 is lower than the secondary flotation column 7 and the tertiary flotation column 9, and is connected to the feed inlet of the tertiary flotation column 9 via a pipeline with pump 24. The secondary cleaning ore slurry tank 10 is lower than the tertiary flotation column 9, and is connected to the concentrate slurry storage tank via a pipeline with pump 25. The inlets of pumps 23, 24, and 25 are also connected to the process water tank via pipelines to introduce process water to adjust the density of the phosphate rock slurry in the secondary flotation column 7, the tertiary flotation column 9, and the concentrate slurry storage tank, respectively. The tailings slurry buffer tank 11 is lower than the tailings outlet of the primary flotation column 5 and the secondary flotation column 7, and is connected to the thickener 12 via a pipeline with pump 26. The tailings overflow buffer tank 13 is lower than the clear liquid outlet of the thickener 12 and is connected to the filter press 14 through a pipeline with pump 7 27. The underflow outlet of the thickener 12 is connected to the secondary pre-decomposition tank 4 through a pipeline with pump. The filtrate outlet of the filter press 14 is higher than the filtrate collection tank 15.

[0032] Example 5 Example 5 provides a phosphate rock flotation system capable of removing organic matter. Its structure is basically the same as that of Example 1, except that the primary mixer 1 and the secondary mixer 3 in this example are both SK-type static mixers. The primary flotation column 5, the secondary flotation column 7, and the tertiary flotation column 9 are identical and arranged side by side.

[0033] Example 6 Example 6 provides a phosphate rock flotation system capable of removing organic matter, and the specifications of each structure are shown in Table 1: Table 1

[0034] Based on an annual production of 500,000 tons, the beneficial effects are as follows: I. Reduce the amount of defoamer used. Before the improvement, the monthly usage of defoamer was 100 tons / month, the consumption of defoamer was 1 kg / t P2O5, and the monthly cost was 1.28 million yuan. After the improvement, the consumption of defoamer can be reduced to 0.5 kg / t P2O5, saving 6.4 million yuan in auxiliary material costs annually.

[0035] Second, after the renovation, using pure imported ore for production, the insoluble phosphorus in phosphogypsum can be reduced from more than 2.5% to about 1.0%, improving the phosphorus recovery rate. Based on an annual output of 500,000 tons, 50 / 4*5.3*(1.8%-1.0%)=0.53 million tons of P2O5, which is equivalent to 20,000 tons of phosphate rock (28.0% phosphate rock).

[0036] Third, after the modification, the COD of the produced phosphate decreased to 1000ppm.

[0037] IV. The magnesium content is similar to that before the improvement, which meets the usage requirements.

[0038] V. Operating Costs: Electricity cost: 13.5 KW·h / t raw ore, equivalent to RMB 9.77 / ton, RMB 4.88 million / year; Personnel cost: RMB 360,000 / year; Depreciation cost: RMB 1.39 million; Annual operating cost: RMB 6.59 million.

[0039] 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 phosphate rock flotation system capable of removing organic matter, comprising a slurry storage tank, a flotation column, a tailings slurry buffer tank (11), a thickener (12), a tailings overflow buffer tank (13), and a concentrate slurry storage tank, wherein the tailings outlet of the flotation column is connected to the tailings slurry buffer tank (11) via a pipeline; the feed inlet of the thickener (12) is connected to the tailings slurry buffer tank (11) via a pipeline, and its clarified liquid outlet is connected to the tailings overflow buffer tank (13) via a pipeline; characterized in that, The system also includes a primary mixer (1), a primary pre-decomposition tank (2), a secondary mixer (3), a secondary pre-decomposition tank (4), a filter press (14), and a filtrate collection tank (15). The slurry storage tank, the primary mixer (1), the primary pre-decomposition tank (2), the secondary mixer (3), the secondary pre-decomposition tank (4), the flotation column, and the concentrate slurry storage tank are connected in sequence by pipelines. The tailings overflow buffer tank (13), the filter press (14), the filtrate collection tank (15), and the primary pre-decomposition tank (2) are connected in sequence by pipelines. The underflow outlet of the thickener (12) is connected to the secondary pre-decomposition tank (4) by pipelines. The feed inlets of the primary mixer (1) and the secondary mixer (3) are also connected to the acid storage tank and the concentrated sulfuric acid storage tank of the phosphoric acid extraction unit by pipelines.

2. The phosphate rock flotation system capable of removing organic matter according to claim 1, characterized in that, The flotation column includes a primary flotation column (5), a rougher slurry tank (6), a secondary flotation column (7), a primary cleaner slurry tank (8), a tertiary flotation column (9), and a secondary cleaner slurry tank (10). The secondary pre-decomposition tank (4), the primary flotation column (5), the rougher slurry tank (6), the secondary flotation column (7), the primary cleaner slurry tank (8), the tertiary flotation column (9), the secondary cleaner slurry tank (10), and the concentrate storage tank are connected in sequence by pipelines. The tailings outlets of the primary flotation column (5) and the secondary flotation column (7) are connected to the tailings slurry buffer tank (11) by pipelines. The tailings outlet of the tertiary flotation column (9) is connected to the rougher slurry tank (6) by pipelines. The rougher slurry tank (6) is also connected to the flotation reagent supply device by pipelines.

3. The phosphate rock flotation system capable of removing organic matter according to claim 2, characterized in that, The wastewater outlets of the primary flotation column (5), the secondary flotation column (7), and the tertiary flotation column (9) are all connected to the primary pre-decomposition tank (2) via pipelines.

4. The phosphate rock flotation system capable of removing organic matter according to claim 2, characterized in that, The roughing slurry tank (6) is lower than the primary flotation column (5) and the secondary flotation column (7) and is connected to the feed inlet of the secondary flotation column (7) through a pipeline with pump three (23). The primary cleaning slurry tank (8) is lower than the secondary flotation column (7) and the tertiary flotation column (9) and is connected to the feed inlet of the tertiary flotation column (9) through a pipeline with pump four (24). The secondary cleaning slurry tank (10) is lower than the tertiary flotation column (9) and is connected to the concentrate slurry storage tank through a pipeline with pump five (25). The inlets of pump three (23), pump four (24) and pump five (25) are also connected to the process water tank through pipelines.

5. The phosphate rock flotation system capable of removing organic matter according to claim 2, characterized in that, The system also includes a ground tank (16), and the overflow ports of the primary pre-decomposition tank (2), secondary pre-decomposition tank (4), rougher slurry tank (6), primary cleaner slurry tank (8), secondary cleaner slurry tank (10), tailings slurry buffer tank (11) and tailings overflow buffer tank (13) are all connected to the ground tank (16) through pipelines. The ground tank (16) is connected to the feed port of the thickener (12) through a pipeline with a pump (28).

6. The phosphate rock flotation system capable of removing organic matter according to claim 2, characterized in that, Agitators are provided in the slurry storage tank, the primary pre-decomposition tank (2), the secondary pre-decomposition tank (4), the roughing slurry tank (6), the primary cleaning slurry tank (8), the secondary cleaning slurry tank (10), the tailings slurry buffer tank (11), the tailings overflow buffer tank (13), and the concentrate slurry storage tank.

7. The phosphate rock flotation system capable of removing organic matter according to claim 2, characterized in that, The primary mixer (1) and the secondary mixer (3) are both SK-type static mixers with a diameter of 219mm and a length of 1500mm. The primary flotation column (5), the secondary flotation column (7), and the tertiary flotation column (9) are the same and have a diameter of 4.2m and a height of 10m. The primary pre-decomposition tank (2) and the secondary pre-decomposition tank (4) have a diameter of 5m and a height of 7m.

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