Independent washing system for filter in semi-hydrated-dihydrated wet-process phosphoric acid process

Abstract

The utility model discloses an independent washing system of a semi-hydrated-dihydrated wet-process phosphoric acid process filter, which solves the problems of narrow control index, strong correlation between phosphorus balance and water balance of semi-hydrated filtration and dihydrated filtration and high operation difficulty in the existing system. According to the technical scheme, the device comprises a semi-water filter (1) and a two-water filter (2), and a two-water acid return outlet of a filter area (2.1) of the two-water filter (2) is connected with a semi-water filter cloth flushing water buffer tank (9) through a two-water acid return pump (8); an upper-section clear liquid outlet of the semi-water filter cloth flushing water buffer tank (9) is connected with a filter cloth washing area (1.4) of the semi-water filter (1) through a semi-water filter cloth flushing water delivery pump (10), a semi-water filter cloth flushing water tank (5) and a semi-water filter cloth flushing water pump (6); and the semi-water filter cloth washing water tank is provided with a heating device. The utility model can effectively break the strong relevance between washing balance and decoupling, reduce the operation difficulty of the device, improve the stability and elasticity of the system, save energy and reduce consumption.

Description

Technical Field

[0002] The utility model relates to the field of wet-process phosphoric acid, in particular to an independent washing system for a filter in a semi-aqueous-dihydrate wet-process phosphoric acid process. Technical Field

[0003] The semi-water-dihydrate wet phosphoric acid process using the two-step recrystallization concentrated acid process has the advantages of low energy consumption, high phosphorus yield, good product quality, and high quality phosphogypsum. The above process involves a semi-water filter and a dihydrate filter. Due to the strong correlation between the two, the problem of water balance needs to be considered. For example, the dihydrate return acid of the dihydrate filter is usually sent to the filter cloth washing area of ​​the semi-water filter as flushing water, but when the amount of dihydrate return acid is temporarily excessive, there is a problem of nowhere to store it, or when the dihydrate filter is stopped, the need for flushing the filter cloth of the semi-water filter cannot be met. This leads to the shortcomings of the existing system, such as few control measures, strong correlation between the phosphorus balance and water balance of semi-water filtration and dihydrate filtration, and high difficulty in operation. Background Art

[0004] The purpose of the utility model is to solve the above technical problems and provide an independent washing system for a semi-aqueous-dihydrate wet phosphoric acid process filter that can effectively break the washing balance, decouple the strong correlation between the two, reduce the operating difficulty of the device, and improve the stability and flexibility of the system.

[0005] The utility model discloses an independent washing system for a semi-aqueous-dihydrate wet phosphoric acid process filter, comprising a semi-aqueous filter (1) and a dihydrate filter (2); the dihydrate acid return outlet of a filter area (2.2) of the dihydrate filter (2) is connected to a semi-aqueous filter cloth washing water buffer tank (9) via a dihydrate acid return pump (8); the upper clear liquid outlet of the semi-aqueous filter cloth washing water buffer tank (9) is connected to a filter cloth washing area (1.4) of the semi-aqueous filter (1) via a semi-aqueous filter cloth washing water delivery pump (10), a semi-aqueous filter cloth washing water tank (5), and a semi-aqueous filter cloth washing water pump (6); and the semi-aqueous filter cloth washing water tank is provided with a heating device.

[0006] The bottom slurry outlet of the semi-water filter cloth flushing water buffer tank (9) is connected to the semi-water gypsum discharge hopper (1.5) of the semi-water filter (1) via a semi-water filter cloth flushing water slurry pump (11).

[0007] The diwater filtration acid outlet of the filtration zone (2.1) of the diwater filter (2) is connected to the first washing zone (1.2) of the semi-water filter (1) via a diwater filtration acid pump.

[0008] The secondary washing water outlet of the secondary washing zone (2.4) of the secondary water filter (2) is connected to the filtering zone (2.2) of the secondary water filter (2).

[0009] The semi-water filtration acid outlet of the filtration area (1.1) of the semi-water filter (1) is connected to the tank area via a semi-water filtration acid pump (3).

[0010] The semi-water acid return outlet of a washing zone (1.2) of the semi-water filter (1) is connected to the semi-water reaction tank via a semi-water acid return pump (4).

[0011] The utility model adopts an independent washing system for the filter, which has the following advantages:

[0012] (1) A semi-water filter cloth flushing water buffer tank is set up to store the temporary excess of dihydrate return acid to meet the requirement of the semi-water filter for flushing water after the dihydrate filter is stopped. At the same time, since the semi-water filter cloth flushing water buffer tank also has a buffering effect, the process parameters can be adjusted by adjusting the semi-water reaction and dihydrate reaction load or operation index, and the stability and flexibility of the device are greatly improved.

[0013] (2) A semi-aqueous filter cloth washing water tank with a heating device is provided to heat the dihydrate return acid before it is sent to the filter cloth washing area (1.4) of the semi-aqueous filter (1), thereby improving the washing efficiency.

[0014] (3) The liquid in the semi-water filter cloth flushing water buffer tank is differentiated and returned. The upper clear liquid in the tank is heated by the two-water filter cloth flushing water tank and then returned to the filter cloth washing area (1.4) of the semi-water filter (1), while the slurry deposited at the bottom is sent to the two-water conversion tank (1.5) of the semi-water filter (1) without heating, thereby reducing the frequency of clogging of the filter cloth nozzle of the filter, improving flexibility, further improving flushing efficiency, and saving energy and reducing consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a system diagram of the utility model.

[0016] Among them, 1. semi-water filter; 1.1 filter area; 1.2 first washing area; 1.3 unloading area; 1.4 filter cloth washing area; 1.5. semi-water gypsum unloading hopper; 2. second water filter; 2.1 filter area; 2.2 first washing area; 2.3 second washing area; 2.4 third washing area; 2.5 unloading area; 2.6 filter cloth washing area; 3. semi-water filter acid pump; 4. semi-water return acid pump; 5. semi-water filter cloth washing water tank; 6. semi-water filter cloth washing water pump; 7. second water filter acid pump; 8. second water return acid pump; 9. semi-water filter cloth washing water buffer tank; 10: semi-water filter cloth washing water delivery pump; 11: semi-water filter cloth washing water slurry pump. DETAILED DESCRIPTION

[0017] The utility model is further explained below in conjunction with the accompanying drawings:

[0018] See also Figure 1, including a semi-water filter 1 and a two-water filter 2. As shown in the figure, the semi-water filter 1 has a filtering area 1.1, a first washing area 1.2, a discharge area 1.3 and a filter cloth washing area 1.4, and a semi-water gypsum hopper 1.5 is arranged below the discharge area 1.3. The two-water filter 2 has a filtering area 2.1, a first washing area 2.2, a second washing area 2.3, a third washing area 2.4, a discharge area 2.5 and a filter cloth washing area 2.6.

[0019] The diwater acid return outlet of the diwater filter 2-washing zone 2.1 is connected to the semi-water filter cloth washing water buffer tank 9 via the diwater acid return pump 8; the upper clear liquid outlet of the semi-water filter cloth washing water buffer tank 9 is connected to the filter cloth washing zone 1.4 of the semi-water filter 1 via the semi-water filter cloth washing water delivery pump 10, the semi-water filter cloth washing water tank 5 (with a heating device), and the semi-water filter cloth washing water pump 6; the bottom slurry outlet of the semi-water filter cloth washing water buffer tank 9 is connected to the semi-water gypsum hopper 1.5 of the semi-water filter 1 via the semi-water filter cloth washing water slurry pump 11.

[0020] The diwater filtration acid outlet of the filtration zone 2.1 of the diwater filter 2 is connected to the first washing zone 1.2 of the semi-water filter 1 via a diwater filtration acid pump; the diwash water outlet of the second washing zone 2.4 of the diwater filter 2 is connected to the first washing zone 2.2 of the diwater filter 2; the semi-water filtration acid outlet of the filtration zone 1.1 of the semi-water filter 1 is connected to the tank area (not shown in the figure) via a semi-water filtration acid pump 3; the semi-water return acid outlet of the first washing zone 1.2 of the semi-water filter 1 is connected to the semi-water reaction tank (not shown in the figure) via a semi-water return acid pump 4.

[0021] Process:

[0022] The semi-water filter 1 receives the semi-water slurry from the semi-water reaction process, and obtains semi-water gypsum after being filtered in sequence by the semi-water filter 1. The semi-water filtered acid is separated by the filtering area 1.1 and sent to the tank area by the semi-water filtered acid pump 3; the semi-water return acid in the first washing area 1.2 is pressurized by the semi-water return acid pump 4 and sent to the semi-water reaction tank; the semi-water gypsum passes through the screw discharger in the discharge area 1.3 of the semi-water filter 1, and vertically falls into the dihydrate conversion tank through the semi-water gypsum discharge hopper 1.5;

[0023] The dihydrate filter 2 receives the dihydrate slurry from the dihydrate reaction process, and obtains dihydrate gypsum after being filtered in sequence by the dihydrate filter 2. The dihydrate filtered acid is separated into dihydrate return acid by the filtering area 2.2, and the dihydrate return acid is sent to the semi-water filter cloth washing water buffer tank 9 for buffering sedimentation by the dihydrate return acid pump 8. The upper clear liquid outlet is pressurized by the semi-water filter cloth washing water delivery pump 10, and then sent to the semi-water filter cloth washing water tank 5 for heating, and then sent to the filter cloth washing area 1.4 of the semi-water filter 1 by the semi-water filter cloth washing water pump 6 as washing water for washing the filter cloth for regeneration. The bottom slurry is pressurized by the semi-water filter cloth washing water slurry pump 11 and then sent back to the semi-water gypsum hopper 1.5 of the semi-water filter 1, and falls vertically into the dihydrate conversion tank; the filter cake washing water of the dihydrate filter 2 is washed three times in reverse flow to form dihydrate return acid as the filter cake washing water of the semi-water filter.

[0024] The utility model system can greatly reduce the difficulty of starting and stopping the device, effectively increase the adjustment measures of the semi-water reaction and diwater conversion control indicators, and can provide the semi-water reaction system and the diwater conversion system with about 2-6 hours of independent operation time. Under the premise of not affecting the continuous operation of the device, the device maintenance time is increased, the device flexibility is improved, and the device start-up rate is increased by 1-3%.

Claims

1. A semi-aqueous-dihydrate wet-process phosphoric acid process filter independent washing system, comprising a semi-aqueous filter (1) and a dihydrate filter (2), characterized in that: The two-water acid return outlet of the first washing zone of the two-water filter (2) is connected to the semi-water filter cloth washing water buffer tank (9) via the two-water acid return pump (8); the upper clear liquid outlet of the semi-water filter cloth washing water buffer tank (9) is connected to the filter cloth washing zone of the semi-water filter (1) via the semi-water filter cloth washing water delivery pump (10), the semi-water filter cloth washing water tank (5), and the semi-water filter cloth washing water pump (6); the semi-water filter cloth washing water tank is provided with a heating device.

2. The semi-aqueous-dihydrate wet-process phosphoric acid process filter independent washing system according to claim 1, characterized in that: The bottom slurry outlet of the semi-water filter cloth flushing water buffer tank (9) is connected to the semi-water gypsum discharge hopper (1.5) of the semi-water filter (1) via a semi-water filter cloth flushing water slurry pump (11).

3. The independent washing system for the filter of the semi-aqueous-dihydrate wet-process phosphoric acid process according to claim 1 or 2, characterized in that: The diwater filtration acid outlet of the filtration zone of the diwater filter (2) is connected to the first washing zone of the semi-water filter (1) via a diwater filtration acid pump.

4. The semi-aqueous-dihydrate wet-process phosphoric acid process filter independent washing system according to claim 1 or 2, characterized in that: The third washing water outlet of the third washing zone of the second water filter (2) is connected to the first washing zone of the second water filter (2).

5. The semi-aqueous-dihydrate wet-process phosphoric acid process filter independent washing system according to claim 1 or 2, characterized in that: The semi-water filtration acid outlet of the filtration zone of the semi-water filter (1) is connected to the tank area via a semi-water filtration acid pump (3).

6. The semi-aqueous-dihydrate wet-process phosphoric acid process filter independent washing system according to claim 1 or 2, characterized in that: The semi-water acid return outlet of a washing zone of the semi-water filter (1) is connected to the semi-water reaction tank via a semi-water acid return pump (4).

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