Phosphorus and fluorine containing sludge treatment system

Abstract

The utility model provides a phosphorus and fluorine-containing sludge treatment system which comprises pulping equipment, reaction equipment and washing equipment, the pulping equipment is provided with a phosphorus and fluorine-containing sludge feeding port, a phosphoric acid dihydrate feeding port and a mixing and stirring mechanism; a pulp outlet pipe of the pulping equipment is connected to the reaction equipment, a gas phase pipeline of the reaction equipment is connected to a gas inlet of the washing equipment, the washing equipment is provided with a liquid phase circulating pipeline and a gas phase emptying pipe, the system further comprises a fluosilicic acid tank collecting tank, and a liquid outlet of the washing equipment is connected to the fluosilicic acid tank collecting tank; and a liquid phase discharge pipe of the reaction equipment is connected to a wet-process phosphoric acid section. The system provided by the utility model has the advantages of simple required equipment, lower cost, capability of respectively recycling phosphorus and fluorine in the sludge containing phosphorus and fluorine while treating the sludge containing phosphorus and fluorine, capability of turning waste into wealth, economy, environmental protection, continuous operation and high treatment efficiency.

Description

Technical Field

[0001] The utility model belongs to the field of environmental protection of chemical production and relates to a phosphorus-fluorine-containing sludge treatment system. Background Art

[0002] At present, the treatment and emission compliance of leachate from phosphogypsum resource bases has become a critical environmental issue. The phosphorus and fluorine contents in the leachate are relatively high. Most chemical companies use sedimentation method to remove the phosphorus and fluorine. However, a large amount of phosphorus and fluorine-containing sludge cannot be effectively treated and is generally directly stored or landfilled, which has a great impact on the environment. In addition, the phosphorus and fluorine in the leachate cannot be recovered, resulting in a waste of resources. Summary of the invention

[0003] The utility model provides a phosphorus-fluorine-containing sludge treatment system, which can effectively recover phosphorus and fluorine therein, reduce environmental pressure, and improve economic benefits.

[0004] The technical solution of the utility model is to provide a phosphorus-fluorine sludge treatment system, comprising pulping equipment, reaction equipment and washing equipment, wherein the pulping equipment is provided with a phosphorus-fluorine sludge addition port and a dihydrate phosphoric acid addition port, and is also provided with a mixing and stirring mechanism; a pulp outlet pipe of the pulping equipment is connected to the reaction equipment, a gas phase pipeline of the reaction equipment is connected to the washing equipment for washing, the washing equipment is provided with a liquid phase circulation pipeline, and the washing equipment is also provided with a gas phase emptying pipe, the system also comprises a fluorosilicic acid tank collecting tank, and a liquid outlet of the washing equipment is connected to the fluorosilicic acid tank collecting tank; a liquid phase discharge pipe of the reaction equipment is connected to a wet phosphoric acid section.

[0005] Furthermore, the pulping equipment includes a pulp mixing tank and a pulp collecting tank, and the outlet of the pulp mixing tank is connected to the pulp collecting tank.

[0006] Furthermore, the mixing and stirring mechanism is a stirring paddle, which is located in a slurry collecting tank, and the slurry collecting tank is connected to the reaction equipment through a slurry outlet pipe and a delivery pump.

[0007] Furthermore, the reaction equipment is provided with a concentrated sulfuric acid adding pipeline.

[0008] Furthermore, the reaction equipment is provided with a heating jacket or a heating coil.

[0009] Furthermore, the washing equipment comprises a first washing tower and a second washing tower connected in series, the gas phase pipeline of the reaction equipment is connected to the first washing tower, the gas phase pipeline of the first washing tower is connected to the air inlet of the second washing tower, a washing water replenishing pipeline is provided above the second washing tower, and the liquid phase outlet of the second washing tower is connected to the washing liquid inlet pipeline above the first washing tower.

[0010] Furthermore, the liquid outlet of the first washing tower is connected to the fluorosilicic acid tank collecting tank, and the fluorosilicic acid tank collecting tank is also provided with a discharge pipe, and the discharge pipe is provided with a branch pipe connected to the washing liquid inlet pipe above the first washing tower.

[0011] The utility model has the following beneficial effects:

[0012] When treating phosphorus-fluorine-containing sludge (mainly composed of CaHPO4 and CaF2), the utility model uses dihydrate phosphoric acid as the mother liquor to adjust the phosphorus-fluorine-containing sludge into slurry to generate Ca(H2pO4)2, which is then reacted with concentrated sulfuric acid to obtain H3PO4, recovering phosphorus in the sludge and making the reaction more uniform and sufficient. CaF2 reacts with concentrated sulfuric acid to obtain HF gas, recovering fluorine in the sludge. The reaction formula involved in the reaction is:

[0013] CaHPO4+H3PO4=Ca(H2pO4)2

[0014] Ca(H2pO4)2+H2SO4+2H2O=CaSO4·2H2O +2H3PO4

[0015] CaF2+H2SO4+2H2O=CaSO4·2H2O+2HF.

[0016] The system provided by the utility model requires simple equipment and has low cost. It can also recover phosphorus and fluorine in phosphorus-fluorine sludge while treating the sludge, thus turning waste into treasure and being economical and environmentally friendly. In addition, the system can operate continuously and has high treatment efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a structural schematic diagram of the utility model system.

[0018] In the figure, 1 is a slurry mixing tank, 2 is a slurry collecting tank, 3 is a phosphorus-fluorine slurry delivery pump, 4 is a reaction equipment, 5 is an electric gate valve, 6 is a mixing and stirring mechanism, 7 is a reaction kettle stirring paddle, 8 is a first washing tower, 9 is a circulating pump, 10 is a fan, 11 is a second washing tower, 12 is a fluorosilicic acid tank, 13 is a fluorosilicic acid delivery pump, and 14 is a reaction slurry delivery pump. DETAILED DESCRIPTION

[0019] The embodiments of the present invention will be described in detail below in conjunction with examples, but those skilled in the art will understand that the following examples are only used to illustrate the present invention and should not be construed as limiting the scope of the present invention.

[0020] Example 1

[0021] The utility model provides a phosphorus-fluorine sludge treatment system, such as Figure 1As shown, it includes pulping equipment, reaction equipment and washing equipment, wherein the pulping equipment is provided with an inlet for adding phosphorus-containing fluorine sludge and a dihydrate phosphoric acid, and is also provided with a mixing and stirring mechanism; the pulping pipe of the pulping equipment is connected to the reaction equipment, the gas phase pipeline of the reaction equipment is connected to the air inlet of the washing equipment, the washing equipment is provided with a liquid phase circulation pipeline, and the washing equipment is also provided with a gas phase exhaust pipe, the system also includes a fluorosilicic acid tank collection tank, the liquid outlet of the washing equipment is connected to the fluorosilicic acid tank collection tank; the liquid phase discharge pipe of the reaction equipment is connected to the wet phosphoric acid section. The liquid phase discharge pipe of the reaction equipment is connected to the wet phosphoric acid section to recover phosphorus through a reaction slurry delivery pump 14.

[0022] Preferably, the pulping equipment comprises a pulping tank 1 and a pulp collecting tank 2, and the outlet of the pulping tank is connected to the pulp collecting tank. After the phosphorus-fluorine-containing sludge is transported to the pulping tank 1, phosphoric acid (dihydrate phosphoric acid, containing about 23% P2O5) produced by the dihydrate process is adjusted into slurry and then flows into the pulp collecting tank 2. An electric gate valve 5 can also be provided between the pulping tank 1 and the pulp collecting tank 2.

[0023] Preferably, the mixing and stirring mechanism 6 is a stirring paddle located in a slurry collecting tank, and the slurry collecting tank is connected to the reaction equipment 4 through a slurry outlet pipe and a phosphorus-fluorine-containing slurry delivery pump 3 . The reaction equipment 4 is also provided with a reaction kettle stirring paddle 7 .

[0024] Preferably, the reaction equipment is provided with a concentrated sulfuric acid adding pipeline, and after the material in the slurry collecting tank 2 is transported to the reaction equipment, 98% concentrated sulfuric acid is added for reaction. More preferably, the reaction equipment is provided with a heating jacket or a heating coil, and the equipment is heated according to the reaction needs to promote the reaction.

[0025] Preferably, the washing equipment is a first washing tower 8 and a second washing tower 11 connected in series, the gas phase pipeline of the reaction equipment is connected to the first washing tower, the gas phase pipeline of the first washing tower is connected to the air inlet of the second washing tower through a fan 10, a washing water replenishing pipeline is provided above the second washing tower, and the liquid phase outlet of the second washing tower is connected to the washing liquid inlet pipeline above the first washing tower through a circulating pump 9.

[0026] Preferably, the liquid outlet of the first washing tower is connected to the fluorosilicic acid tank collecting tank 12, and the fluorosilicic acid tank collecting tank is also provided with a discharge pipe, on which a fluorosilicic acid delivery pump 13 is provided, and a branch pipe is also provided to connect to the washing liquid inlet pipe above the first washing tower. The fluorosilicic acid in the fluorosilicic acid tank collecting tank is circulated and absorbed, and after the fluorosilicic acid reaches a certain concentration, it is transported to the anhydrous hydrogen fluoride device to recover fluorine.

[0027] The specific processing methods are:

[0028] 1) Transport the phosphorus-fluorine sludge into the slurry mixing tank, add 1 to 2 times its mass of dihydrate phosphoric acid to make slurry, and then let the slurry flow into the slurry collecting tank, turn on the stirring paddle in the slurry collecting tank to stir, so as to prevent the slurry from settling and being unable to be transported.

[0029] 2) Add washing water to the second washing tower, control the liquid level in the second washing tower not to be higher than the pipe connecting the second washing tower to the fan outlet, turn on the circulation pump to add water to the fluorosilicic acid tank, and turn on the fan after the liquid level overflows a certain distance from the outlet of the lower liquid pipe of the first washing tower. Control the liquid level in the fluorosilicic acid tank through the circulation pump to ensure that the outlet of the lower liquid pipe of the first washing tower is always in a liquid-sealed state.

[0030] 3) Add 98% concentrated sulfuric acid to the reaction equipment. When the liquid level reaches 1 / 3, introduce steam to control the temperature in the reaction equipment at 85°C~105°C, turn on the stirring paddle of the reaction equipment, and at the same time, pump the phosphorus-fluorine slurry into the reaction equipment through the phosphorus-fluorine slurry delivery pump for decomposition reaction. Control the liquid level of the reaction equipment by the amount of phosphorus-fluorine slurry added, and control the decomposition reaction time to 1 hour.

[0031] 4) When the concentration of fluorosilicic acid in the fluorosilicic acid tank is below 12%, the fluorosilicic acid is pumped into the first washing tower through the connecting pipe from the fluorosilicic acid delivery pump to the circulating water pump outlet to continue to absorb fluorine-containing gas to increase the concentration. When the concentration reaches 12%, the fluorosilicic acid delivery pump is turned on to transport the fluorosilicic acid to the anhydrous hydrogen fluoride device to recover fluorine. When the concentration exceeds 18%, the circulating water pump is turned on to add low-concentration washing water to the first washing tower to reduce the concentration.

[0032] 5) After the reaction time in the reaction equipment reaches 1 hour, the reaction slurry delivery pump is turned on to pump the reaction slurry into the wet-process phosphoric acid production device to recover phosphorus.

[0033] The above embodiments are only for illustrating the technical ideas and features of the utility model, and the contents are only preferred embodiments of the utility model, but the protection scope of the utility model is not limited thereto. Within the technical scope disclosed by the utility model, equivalent changes or improvements based on the technical solution and utility model concept of the utility model should be included in the protection scope of the utility model.

Claims

1. A phosphorus-fluorine sludge treatment system, characterized in that: The invention comprises pulping equipment, reaction equipment and washing equipment, wherein the pulping equipment is provided with a phosphorus-fluorine sludge addition port and a dihydrate phosphoric acid addition port, and is also provided with a mixing and stirring mechanism; the pulping equipment's pulping outlet pipe is connected to the reaction equipment, the reaction equipment's gas phase pipeline is connected to the washing equipment's gas inlet, the washing equipment is provided with a liquid phase circulation pipeline, the washing equipment is also provided with a gas phase exhaust pipe, the system also comprises a fluorosilicic acid tank collecting tank, the liquid outlet of the washing equipment is connected to the fluorosilicic acid tank collecting tank; the liquid phase discharge pipe of the reaction equipment is connected to the wet phosphoric acid section.

2. The system according to claim 1, characterized in that: The pulping equipment comprises a pulp mixing tank and a pulp collecting tank, and the outlet of the pulp mixing tank is connected to the pulp collecting tank.

3. The system according to claim 2, characterized in that: The mixing and stirring mechanism is a stirring paddle, which is located in a slurry collecting tank, and the slurry collecting tank is connected to the reaction equipment through a slurry outlet pipe and a delivery pump.

4. The system according to claim 1, characterized in that: The reaction equipment is provided with a pipeline for adding concentrated sulfuric acid.

5. The system according to claim 1, characterized in that: The reaction equipment is provided with a heating jacket or a heating coil.

6. The system according to claim 1, characterized in that: The washing equipment comprises a first washing tower and a second washing tower connected in series, a gas phase pipeline of the reaction equipment is connected to the first washing tower, a gas phase pipeline of the first washing tower is connected to an air inlet of the second washing tower, a washing water replenishing pipeline is provided above the second washing tower, and a liquid phase outlet of the second washing tower is connected to a washing liquid inlet pipeline above the first washing tower.

7. The system according to claim 1, characterized in that: The liquid outlet of the first washing tower is connected to the fluorosilicic acid tank collecting tank, and the fluorosilicic acid tank collecting tank is also provided with a discharge pipe, and the discharge pipe is provided with a branch pipe connected to the washing liquid inlet pipeline above the first washing tower.

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