Method for circularly inducing crystallization, hardness removal and desalination of calcium sulfate in high calcium sulfate type wastewater

Abstract

The invention provides a method for circularly inducing crystallization, hardness removal and desalination of calcium sulfate in high calcium sulfate type wastewater. The method adopts a system for circularly inducing crystallization, hardness removal and desalination of calcium sulfate in high calcium sulfate type wastewater. The system for calcium sulfate circulation induced crystallization, hardness removal and desalination of the high calcium sulfate type wastewater comprises a crystal inducing carrier mixing device, wherein the crystal inducing carrier mixing device is connected with an induced crystallization device. According to the method, induced crystallization of Ca < 2 + > and SO4 < 2-> in water is used as a mechanism, the purpose of removing Ca < 2 + > and SO4 < 2-> in water is achieved through the induction effect of a crystal inducing carrier in the induced crystallization device, and compared with known methods, the induced crystallization device achieves circulating crystallization of the crystal inducing carrier through structural optimization design, the utilization rate of the crystal inducing carrier is increased, and the service life of the crystal inducing carrier is prolonged. The treatment cost is effectively reduced.

Description

Technical Field

[0001] The invention belongs to the field of water treatment, relates to high calcium sulfate type wastewater, and specifically relates to a method for removing hardness and desalting by calcium sulfate circulation-induced crystallization for high calcium sulfate type wastewater. Background Art

[0002] The annual output of mine water in my country can reach 6.0×10 9 m 3 Of the above, 57% of the total amount is high-mineralized mine water with a total dissolved solid (TDS) greater than 1000 mg / L. Mine water with high sulfate and calcium salt content in the water is called high calcium sulfate mine water. The resource treatment of this type of water quality aims to remove hardness, sulfate and other inorganic ions in the water. It is usually treated by combining pretreatment and deep desalination treatment. "Multi-stage membrane concentration + membrane thermal coupling desalination" is a process combination that is often used in mine water resource applications. In the treatment of this combined process, a certain amount of scale inhibitor will be added to the water before the multi-stage membrane concentration unit treatment. Under the action of the scale inhibitor and membrane concentration, the membrane concentrate produced contains double the ion content. The ion content in this type of water quality is usually in an oversaturated state, such as Ca in the concentrate. 2+ and SO4 2- Under the influence of scale inhibitors, the water will be concentrated exponentially to form water with supersaturated CaSO4 content. When this type of concentrated water is treated with traditional chemical precipitation methods, there are usually problems such as low treatment efficiency, high chemical consumption, and high operation and maintenance costs. In actual operation, water with high ion content is prone to equipment clogging. Summary of the invention

[0003] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a method for removing hardness and desalination of high-calcium sulfate type wastewater by calcium sulfate circulation induced crystallization, so as to solve the technical problem that the treatment efficiency of the treatment method for high-calcium sulfate type wastewater in the prior art needs to be further improved.

[0004] Another object of the present invention is to provide a method for removing hardness and salt from high-calcium sulfate type wastewater by calcium sulfate circulation induced crystallization, so as to solve the technical problem that the treatment economy of the treatment method for high-calcium sulfate type wastewater in the prior art needs to be further improved.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions to achieve the above problems:

[0006] A method for removing hardness and salt from high-calcium sulfate type wastewater by calcium sulfate circulation induction crystallization. The method adopts a system for removing hardness and salt from high-calcium sulfate type wastewater by calcium sulfate circulation induction crystallization. The system for removing hardness and salt from high-calcium sulfate type wastewater by calcium sulfate circulation induction crystallization comprises a crystal inducing carrier mixing device, which is connected to the crystal inducing device.

[0007] This method includes the following four paths:

[0008] Path one: the raw water of high calcium sulfate type wastewater directly enters the induced crystallization device for treatment. Before the induced crystallization device starts to operate, all the crystal-inducing carriers are added into the inner circulation cylinder. During the operation, the crystal-inducing carriers are directly refluxed without passing through the crystal-inducing carrier mixing device when they are circulating externally.

[0009] Path two, the raw water of high calcium sulfate type wastewater directly enters the induced crystallization device for treatment. Before the induced crystallization device starts to operate, all the crystal-inducing carriers are added into the inner circulation cylinder. During the operation, the crystal-inducing carriers are first discharged into the crystal-inducing carrier mixing device when they circulate externally, and then refluxed after being evenly mixed with the raw water.

[0010] Path three, the raw water of high calcium sulfate type wastewater first enters the crystal-inducing carrier mixing device to be mixed with the crystal-inducing carrier, and after being evenly mixed, it enters the induced crystallization device for continuous operation. During the operation, the crystal-inducing carrier circulates externally and directly refluxes without passing through the crystal-inducing carrier mixing device.

[0011] Path four, the raw water of high calcium sulfate type wastewater first enters the crystal-inducing carrier mixing device to be mixed with the crystal-inducing carrier, and after being evenly mixed, it enters the induced crystallization device for continuous operation. During the operation, the crystal-inducing carrier is first discharged into the crystal-inducing carrier mixing device when it is circulated externally, and then refluxed after being evenly mixed with the raw water.

[0012] The present invention also has the following technical features:

[0013] The above-mentioned route 1 is applicable to the raw water of high calcium sulfate type wastewater, the calcium sulfate supersaturation is greater than or equal to 1.2, and the Ca 2+ Content greater than or equal to 1800mg / L, SO4 2- Desalination and hardness removal of water with a content greater than or equal to 14000 mg / L.

[0014] The second route is suitable for the raw water of high calcium sulfate wastewater with calcium sulfate supersaturation greater than 0.9 and less than 1.2, and Ca 2+ Content greater than 1500mg / L, less than 1800mg / L, SO4 2- Desalination and hardness removal of water with a content greater than 11000mg / L and less than 14000mg / L.

[0015] The third route is applicable to the raw water of high calcium sulfate wastewater, where the calcium sulfate supersaturation is greater than 0.6 and less than or equal to 0.9, and Ca 2+ Content greater than 1200mg / L, less than or equal to 1500mg / L, SO4 2- Desalination and hardness removal of water with a content greater than 8000mg / L and less than or equal to 11000mg / L.

[0016] The fourth route is applicable to the raw water of high calcium sulfate wastewater with calcium sulfate supersaturation less than or equal to 0.6, and Ca 2+ Content is less than or equal to 1200mg / L, SO4 2- Desalination and hardness removal of water with a content of less than or equal to 8000mg / L.

[0017] The crystal-inducing carrier mixing device includes a mixing tank body, the bottom of the mixing tank body is connected to a first water inlet pipe, the side wall of the mixing tank body located above the first water inlet pipe is connected to the inner end of a first crystal-inducing carrier addition pipe, and the top of the mixing tank body is provided with a first water outlet pipe.

[0018] The induced crystallization device includes an outer cylinder, which has a closed bottom and an open top. An inner cylinder, an inner circulation cylinder, and a middle cylinder are coaxially arranged in sequence from the inside to the outside in the outer cylinder. The top and bottom of the inner cylinder are both open. The bottom of the inner circulation cylinder is closed and the top is open. The top of the middle cylinder is closed and the bottom is open. The top of the inner cylinder is lower than the top of the inner circulation cylinder, the top of the inner circulation cylinder is lower than the top of the middle cylinder, and the top of the middle cylinder is higher than the top of the outer cylinder.

[0019] The bottom of the inner circulation cylinder is connected to the inner end of the second water inlet pipe, the outer end of the second water inlet pipe is connected to the first water outlet pipe, and a water distributor is arranged at the bottom of the inner circulation cylinder above the inner end of the water inlet pipe, and the water distributor is located below the inner cylinder.

[0020] The inner circulation cylinder is located on the side wall above the water distributor and is connected with the inner end of the second crystal inducing carrier dosing pipe.

[0021] A second water outlet pipe is arranged on the top of the outer cylinder.

[0022] The bottom of the outer cylinder is connected to one end of a crystal-inducing carrier discharge pipe, the other end of the crystal-inducing carrier discharge pipe is connected to a rotary drum mud-water separation device, the mud outlet end of the rotary drum mud-water separation device is connected to a crystal-inducing carrier storage barrel, the crystal-inducing carrier storage barrel is connected to the outer end of a first crystal-inducing carrier feeding pipe through a crystal-inducing carrier conveying pump to realize wet external circulation of the crystal-inducing carrier; the crystal-inducing carrier storage barrel is connected to the outer end of a second crystal-inducing carrier feeding pipe through a screw conveyor to realize dry external circulation of the crystal-inducing carrier.

[0023] The inner circulation cylinder is a variable outer diameter structure. The lower outer diameter of the inner circulation cylinder is the same as that of the inner cylinder, the upper outer diameter of the inner circulation cylinder is larger than that of the inner cylinder, and the inner cylinder is located at the upper part of the inner circulation cylinder.

[0024] A mixing and stirring motor is arranged on the top of the mixing tank body, and the mixing and stirring motor drives the mixing and stirring device located in the mixing tank body.

[0025] A top stirring motor is installed on the top of the middle cylinder, and the top stirring motor drives the upper stirrers located in the inner cylinder and the inner circulation cylinder.

[0026] A bottom stirring motor is installed at the outer bottom of the outer cylinder, and the bottom stirring motor drives a lower stirrer located at the inner bottom of the outer cylinder.

[0027] An annular water storage tank is arranged on the inner wall of the top of the outer cylinder, and the annular water storage tank is connected with the second water outlet pipe.

[0028] The bottom of the inner circulation cylinder is connected with a crystal inducing carrier exhaust pipe.

[0029] A first supporting base is arranged at the bottom of the mixing tank body; a second supporting base is arranged at the bottom of the outer cylinder.

[0030] Compared with the prior art, the present invention has the following technical effects:

[0031] (I) The method of the present invention uses Ca in water 2+ and SO4 2- The induced crystallization mechanism is to remove Ca2+ from water through the induction effect of the crystal carrier in the induced crystallization device. 2+ and SO4 2- For the purpose of, compared with the known methods, the induced crystallization device in the present invention realizes the cyclic crystallization of the crystal-inducing carrier through structural optimization design, improves the utilization rate of the crystal-inducing carrier, and effectively reduces the processing cost.

[0032] (II) The method of the present invention can carry out various forms of external circulation of the crystal-inducing carrier, thus avoiding the scaling and clogging problems in the crystal-inducing device, further improving the utilization efficiency of the crystal-inducing carrier, and optimizing the continuous and stable operation effect of the system.

[0033] (III) The method of the present invention can optimize the treatment effect of high calcium sulfate wastewater of different types of water quality through different addition and reflux methods of the crystal-inducing carrier, and has good adaptability to water quality.

[0034] (IV) The method of the present invention can achieve efficient softening and desalination treatment of high calcium sulfate type wastewater without adding any reagents, while reducing the treatment cost and avoiding the influence of reagents on the composition of the crystallized product. The only crystal formed during the treatment is calcium sulfate, which is effectively attached to the crystal-inducing carrier to form a high-purity gypsum product that can be recycled after dehydration, achieving zero emission.

[0035] (V) The method of the present invention has good softening and desalination effect, low operating cost, small footprint and can achieve "zero discharge" high calcium sulfate wastewater treatment technology equipment and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 It is a schematic diagram of the structure of a system for removing hardness and desalination by calcium sulfate circulation-induced crystallization for high-calcium sulfate wastewater.

[0037] Figure 2 Schematic diagram of four different pathways for calcium sulfate cycle-induced crystallization desalination of high calcium sulfate wastewater.

[0038] The meanings of the numbers in the figure are: 1-crystallization-inducing carrier mixing device, 2-induced crystallization device, 3-high calcium sulfate type wastewater raw water storage tank.

[0039] 101 - mixing tank body, 102 - first water inlet pipe, 103 - first crystal inducing carrier addition pipe, 104 - first water outlet pipe, 105 - mixing and stirring motor, 106 - mixing and stirring device, 107 - first supporting base.

[0040] 201-outer cylinder, 202-inner cylinder, 203-inner circulation cylinder, 204-middle cylinder, 205-second water inlet pipe, 206-water distributor, 207-second crystal-inducing carrier addition pipe, 208-second water outlet pipe, 209-crystal-inducing carrier discharge pipe, 210-rotary drum mud-water separation equipment, 211-crystal-inducing carrier storage barrel, 212-crystal-inducing carrier delivery pump, 213-screw conveyor, 214-top stirring motor, 215-upper agitator, 216-bottom stirring motor, 217-lower agitator, 218-annular water storage tank, 219-crystal-inducing carrier emptying pipe, 220-second supporting base.

[0041] The specific contents of the present invention are further explained in detail below in conjunction with embodiments. DETAILED DESCRIPTION

[0042] It should be noted that, unless otherwise specified, all devices and components in the present invention are devices and components known in the prior art.

[0043] In the present invention, high calcium sulfate wastewater refers to water quality in which the calcium sulfate supersaturation is greater than 0.

[0044] Specific embodiments of the present invention are given below. It should be noted that the present invention is not limited to the following specific embodiments, and all equivalent changes made on the basis of the technical solution of this application fall within the protection scope of the present invention.

[0045] Embodiment 1:

[0046] This embodiment provides a calcium sulfate circulation induced crystallization desalination system for high calcium sulfate type wastewater, such as Figure 1 As shown, it includes a crystal-inducing carrier mixing device 1, which is connected to an inducing crystallization device 2.

[0047] The crystal-inducing carrier mixing device 1 includes a mixing tank body 101, the bottom of the mixing tank body 101 is connected to a first water inlet pipe 102, the inner end of a first crystal-inducing carrier addition pipe 103 is connected to the side wall of the mixing tank body 101 above the first water inlet pipe 102, and a first water outlet pipe 104 is arranged on the top of the mixing tank body 101.

[0048] The induced crystallization device 2 includes an outer cylinder 201, which has a closed bottom and an open top. An inner cylinder 202, an inner circulation cylinder 203, and a middle cylinder 204 are coaxially arranged in sequence from the inside to the outside in the outer cylinder 201. The top and bottom of the inner cylinder 202 are both open, the bottom of the inner circulation cylinder 203 is closed and the top is open, the top of the middle cylinder 204 is closed and the bottom is open, the top of the inner cylinder 202 is lower than the top of the inner circulation cylinder 203, the top of the inner circulation cylinder 203 is lower than the top of the middle cylinder 204, and the top of the middle cylinder 204 is higher than the top of the outer cylinder 201.

[0049] The bottom of the inner circulation cylinder 203 is connected to the inner end of the second water inlet pipe 205, and the outer end of the second water inlet pipe 205 is connected to the first water outlet pipe 104. A water distributor 206 is provided at the bottom of the inner circulation cylinder 203 above the inner end of the water inlet pipe 104, and the water distributor 206 is located below the inner cylinder 202.

[0050] The inner end of the second crystal inducing carrier dosing pipe 207 is connected to the side wall of the inner circulation cylinder 203 located above the water distributor 206 .

[0051] A second water outlet pipe 208 is disposed at the top of the outer cylinder 201 .

[0052] As a preferred solution of this embodiment, the bottom of the outer cylinder 201 is connected to one end of a crystal-inducing carrier discharge pipe 209, the other end of the crystal-inducing carrier discharge pipe 209 is connected to a rotary drum mud-water separation device 210, the mud outlet end of the rotary drum mud-water separation device 210 is connected to a crystal-inducing carrier storage barrel 211, the crystal-inducing carrier storage barrel 211 is connected to the outer end of the first crystal-inducing carrier addition pipe 103 through a crystal-inducing carrier conveying pump 212 to realize the wet external circulation of the crystal-inducing carrier; the crystal-inducing carrier storage barrel 211 is connected to the outer end of the second crystal-inducing carrier addition pipe 207 through a screw conveyor 213 to realize the dry external circulation of the crystal-inducing carrier.

[0053] As a preferred solution of this embodiment, the inner circulation cylinder 203 is a variable outer diameter structure, the lower outer diameter of the inner circulation cylinder 203 is the same as that of the inner cylinder 202, the upper outer diameter of the inner circulation cylinder 203 is larger than the outer diameter of the inner cylinder 202, and the inner cylinder 202 is located in the upper part of the inner circulation cylinder 203.

[0054] As a preferred solution of this embodiment, a mixing and stirring motor 105 is arranged on the top of the mixing tank body 101 , and the mixing and stirring motor 105 drives a mixing agitator 106 located in the mixing tank body 101 .

[0055] As a preferred solution of this embodiment, a top stirring motor 214 is installed on the top of the middle cylinder 204, and the top stirring motor 214 drives the upper agitator 215 located in the inner cylinder 202 and the inner circulation cylinder 203; the upper agitator 215 is used to improve the mixing state of the raw water and the crystal-inducing carrier when the water inlet flow rate is small.

[0056] As a preferred solution of this embodiment, a bottom stirring motor 216 is installed at the outer bottom of the outer cylinder 201, and the bottom stirring motor 216 drives the lower agitator 217 located at the inner bottom of the outer cylinder 201; the lower agitator 217 is mainly used to prevent scaling of the crystal-inducing carrier deposited at the bottom of the outer cylinder 201, and ensure that the crystal-inducing carrier can be smoothly discharged from the crystal-inducing carrier discharge pipe 209.

[0057] As a preferred solution of this embodiment, an annular water storage tank 218 is provided on the top inner wall of the outer cylinder 201 , and the annular water storage tank 218 is connected to the second water outlet pipe 208 .

[0058] As a preferred solution of this embodiment, the bottom of the inner circulation cylinder 203 is connected with a crystal inducing carrier exhaust pipe 219 .

[0059] As a preferred solution of this embodiment, a first supporting base 107 is provided at the bottom of the mixing tank body 101 ; and a second supporting base 220 is provided at the bottom of the outer cylinder 201 .

[0060] In this embodiment, the bottom of the outer cylinder 201 is a conical structure or an arc structure; the bottom of the inner circulation cylinder 203 is a conical structure or an arc structure.

[0061] In this embodiment, the inner cylinder 202, the inner circulation cylinder 203, the middle cylinder 204 and the outer cylinder 201 are all connected and fixed by ribs.

[0062] In this embodiment, valves and flow meters are provided in the auxiliary pipelines of the crystal-inducing carrier mixing device 1 and the crystal-inducing device 2 as required.

[0063] When the system of this embodiment is in use, the raw water of high calcium sulfate type wastewater and the crystal inducing carrier enter the mixing tank 201 and are evenly mixed with water through stirring, and the formed mixed liquid flows out from the first outlet pipe 104 at the top.

[0064] The mixed liquid enters the inner circulation cylinder 203 through the second water inlet pipe 205 and is evenly distributed through the water distributor 206. Then, the mixed liquid enters the inner cylinder 202 from the bottom to induce crystallization reaction. The Ca in the raw water of high calcium sulfate type wastewater is 2+ and SO4 2- Under the induction of the crystal-inducing carrier, a chemical reaction quickly occurs to generate CaSO4 microcrystals which adhere to the surface of the crystal-inducing carrier, thus achieving the purpose of softening and desalination.

[0065] The mixed liquid formed by the reacted water and the crystal-inducing carrier rises to the top of the inner cylinder 202, and then a part of the carrier with larger particle size sinks into the inner circulation cylinder 203 to form an internal circulation of the crystal-inducing carrier. The other part of the particles with smaller particle size rises to the top of the inner cylinder 202 with the water flow, and then enters the middle cylinder 204 to continue the solid-liquid separation process. The liquid after solid-liquid separation rises from the bottom of the outer cylinder 201 to the annular water storage tank 218 at the top for convergence, and then flows out of the induced crystallization device 2 through the second water outlet pipe 208.

[0066] After solid-liquid separation, the crystal-inducing carrier is deposited at the bottom of the outer cylinder 201 and then discharged from the crystal-inducing carrier discharge pipe 209 for crystal-inducing carrier external circulation. The crystal-inducing carrier external circulation is divided into dry external circulation and wet external circulation; the crystal-inducing carrier enters the crystal-inducing device 2 through the dry external circulation, and the crystal-inducing carrier enters the crystal-inducing carrier mixing device 1 through the wet external circulation.

[0067] Embodiment 2:

[0068] This embodiment provides a method for removing hardness and salt from high-calcium sulfate type wastewater by circulating and inducing crystallization. The method adopts the system for removing hardness and salt from high-calcium sulfate type wastewater provided in Example 1 by circulating and inducing crystallization.

[0069] In this embodiment, when the calcium sulfate circulation induced crystallization de-hardness and desalination system is in operation, the system operating conditions can be flexibly adjusted to form different process paths according to the water quality of the raw water to be treated, the treatment requirements and the land requirements.

[0070] like Figure 2As shown, the method includes the following four paths:

[0071] Path one, the raw water of high calcium sulfate type wastewater directly enters the induced crystallization device 2 for treatment. Before the induced crystallization device 2 starts to operate, all the crystal-inducing carriers are added into the inner circulation drum 203. During the operation, the crystal-inducing carriers are directly refluxed without passing through the crystal-inducing carrier mixing device 1 when they are in external circulation.

[0072] Path two, the raw water of high calcium sulfate type wastewater directly enters the induced crystallization device 2 for treatment. Before the induced crystallization device 2 starts to operate, all the crystal-inducing carriers are added into the inner circulation drum 203. During the operation, the crystal-inducing carriers are first discharged into the crystal-inducing carrier mixing device 1 when they circulate externally, and then refluxed after being evenly mixed with the raw water.

[0073] Path three, the raw water of high calcium sulfate type wastewater first enters the crystal-inducing carrier mixing device 1 to be mixed with the crystal-inducing carrier, and after being evenly mixed, it enters the crystal-inducing device 2 for continuous operation. During the operation, the crystal-inducing carrier circulates externally without passing through the crystal-inducing carrier mixing device 1 and directly refluxes.

[0074] Path four, the raw water of high calcium sulfate type wastewater first enters the crystal-inducing carrier mixing device 1 to be mixed with the crystal-inducing carrier, and after being evenly mixed, it enters the crystal-inducing carrier 2 for continuous operation. During the operation, the crystal-inducing carrier is first discharged into the crystal-inducing carrier mixing device 1 when it is circulated externally, and then refluxed after being evenly mixed with the raw water.

[0075] Path 1 is applicable to high calcium sulfate type wastewater with calcium sulfate supersaturation greater than or equal to 1.2, and Ca 2+ Content greater than or equal to 1800mg / L, SO4 2- Desalination and hardness removal of water with a content greater than or equal to 14000 mg / L.

[0076] Path 2 is applicable to high calcium sulfate type wastewater, where the calcium sulfate supersaturation in the raw water is greater than 0.9 and less than 1.2, and Ca 2+ Content greater than 1500mg / L, less than 1800mg / L, SO4 2- Desalination and hardness removal of water with a content greater than 11000mg / L and less than 14000mg / L.

[0077] Path 3 is applicable to high calcium sulfate type wastewater, where the calcium sulfate supersaturation in the raw water is greater than 0.6 and less than or equal to 0.9, and Ca 2+ Content greater than 1200mg / L, less than or equal to 1500mg / L, SO4 2- Desalination and hardness removal of water with a content greater than 8000mg / L and less than or equal to 11000mg / L.

[0078] Path 4 is applicable to high calcium sulfate type wastewater with calcium sulfate supersaturation less than or equal to 0.6 in the raw water, and Ca 2+ Content is less than or equal to 1200mg / L, SO4 2- Desalination and hardness removal of water with a content of less than or equal to 8000mg / L.

[0079] Specifically, in this embodiment, the Ca in the raw water of high calcium sulfate type wastewater 2+ Content is 1430mg / L, SO4 2- The content is 10013 mg / L. After simulating and calculating the raw water of high calcium sulfate wastewater, its supersaturation index (SI) is 0.62. It is determined that the raw water belongs to the type of water with low supersaturation index and high ion content, and path three is used for treatment.

[0080] Specifically in this embodiment, the crystal inducing carrier is selected from industrial-grade gypsum crystal particles.

[0081] Specifically, in this embodiment, the water inlet flow rate of the induced crystallization device 2 is controlled to be 1m 3 / h, the speed of the upper agitator 215 is controlled at 9r / min, and the speed of the lower agitator 217 is controlled at 4r / min. During the continuous and stable operation of the system, the crystal-inducing carrier at the bottom of the outer cylinder 201 is connected to the outer end of the first crystal-inducing carrier addition pipe 103 through the crystal-inducing carrier delivery pump 212 to realize the wet external circulation of the crystal-inducing carrier, and then refluxes to the crystal-inducing carrier mixing device 1 to mix with the raw water and then reflux.

[0082] Specifically, in this embodiment, during the continuous and stable operation of the system, Ca 2+ The removal rate can reach 45% to 53%.

Claims

1. A method for removing hardness and salt from high calcium sulfate type wastewater by calcium sulfate circulation induction crystallization, characterized in that: The method adopts a system for removing hardness and salting of calcium sulfate-rich wastewater by circulating inducing crystallization. The system for removing hardness and salting of calcium sulfate-rich wastewater by circulating inducing crystallization comprises a crystal-inducing carrier mixing device (1), wherein the crystal-inducing carrier mixing device (1) is connected to an inducing crystallization device (2); This method includes the following four paths: Path 1: The raw water of high calcium sulfate type wastewater directly enters the induced crystallization device (2) for treatment. Before the induced crystallization device (2) starts to operate, all the crystal-inducing carriers are added to the inner circulation drum (203). During the operation, the crystal-inducing carriers are directly refluxed without passing through the crystal-inducing carrier mixing device (1) when they are circulated externally; Path 2: The raw water of high calcium sulfate type wastewater directly enters the induced crystallization device (2) for treatment. Before the induced crystallization device (2) starts to operate, all the crystal-inducing carriers are added to the inner circulation drum (203). During the operation, the crystal-inducing carriers are first discharged into the crystal-inducing carrier mixing device (1) when they circulate externally, and then reflux after being evenly mixed with the raw water. Path three, the raw water of high calcium sulfate type wastewater first enters the crystal inducing carrier mixing device (1) to be mixed with the crystal inducing carrier, and after being evenly mixed, enters the crystal inducing device (2) to continue to operate. During the operation, the crystal inducing carrier circulates externally and directly refluxes without passing through the crystal inducing carrier mixing device (1); Path four, the raw water of high calcium sulfate type wastewater first enters the crystal inducing carrier mixing device (1) to be mixed with the crystal inducing carrier, and after being evenly mixed, it enters the crystal inducing device (2) for continuous operation. During the operation, the crystal inducing carrier is first discharged into the crystal inducing carrier mixing device (1) when it is circulated externally, and then refluxed after being evenly mixed with the raw water.

2. The method for removing hardness and salting of high calcium sulfate type wastewater by calcium sulfate circulation induction crystallization as claimed in claim 1, characterized in that: The above-mentioned route 1 is applicable to the raw water of high calcium sulfate type wastewater, the calcium sulfate supersaturation is greater than or equal to 1.2, and the Ca 2+ Content greater than or equal to 1800mg / L, SO4 2- Desalination and hardness removal of water with a content of 14000mg / L or more; The second route is suitable for the raw water of high calcium sulfate wastewater with calcium sulfate supersaturation greater than 0.9 and less than 1.2, and Ca 2+ Content greater than 1500mg / L, less than 1800mg / L, SO4 2- Desalination and hardness removal of water with a content greater than 11000mg / L and less than 14000mg / L; The third route is applicable to the raw water of high calcium sulfate wastewater, where the calcium sulfate supersaturation is greater than 0.6 and less than or equal to 0.9, and Ca 2+ Content greater than 1200mg / L, less than or equal to 1500mg / L, SO4 2- Desalination and hardness removal of water with a content greater than 8000mg / L and less than or equal to 11000mg / L; The fourth route is applicable to the raw water of high calcium sulfate wastewater with calcium sulfate supersaturation less than or equal to 0.6, and Ca 2+ Content is less than or equal to 1200mg / L, SO4 2- Desalination and hardness removal of water with a content of less than or equal to 8000mg / L.

3. The method for removing hardness and salting of high calcium sulfate type wastewater by calcium sulfate circulation induction crystallization as claimed in claim 1, characterized in that: The crystal-inducing carrier mixing device (1) comprises a mixing tank body (101), the bottom of the mixing tank body (101) is connected to a first water inlet pipe (102), the inner end of a first crystal-inducing carrier dosing pipe (103) is connected to the side wall of the mixing tank body (101) above the first water inlet pipe (102), and a first water outlet pipe (104) is arranged at the top of the mixing tank body (101).

4. The method for removing hardness and desalting by calcium sulfate circulation induced crystallization for high calcium sulfate type wastewater as claimed in claim 3, characterized in that: The induced crystallization device (2) comprises an outer cylinder (201), the outer cylinder (201) has a closed bottom and an open top, an inner cylinder (202), an inner circulation cylinder (203), and a middle cylinder (204) are coaxially arranged in sequence from the inside to the outside of the outer cylinder (201), the top and bottom of the inner cylinder (202) are both open, the bottom of the inner circulation cylinder (203) is closed and the top is open, the top of the middle cylinder (204) is closed and the bottom is open, the top of the inner cylinder (202) is lower than the top of the inner circulation cylinder (203), the top of the inner circulation cylinder (203) is lower than the top of the middle cylinder (204), and the top of the middle cylinder (204) is higher than the top of the outer cylinder (201); The bottom of the inner circulation cylinder (203) is connected to the inner end of the second water inlet pipe (205), the outer end of the second water inlet pipe (205) is connected to the first water outlet pipe (104), and a water distributor (206) is provided at the bottom of the inner circulation cylinder (203) above the inner end of the water inlet pipe (104), and the water distributor (206) is located below the inner cylinder (202); The inner circulation cylinder (203) is located on a side wall above the water distributor (206) and is connected to the inner end of the second crystal inducing carrier dosing pipe (207); A second water outlet pipe (208) is provided at the top of the outer cylinder (201).

5. The method for removing hardness and desalting by calcium sulfate circulation induced crystallization for high calcium sulfate type wastewater as claimed in claim 4, characterized in that: The bottom of the outer cylinder (201) is connected to one end of a crystal inducing carrier discharge pipe (209), the other end of the crystal inducing carrier discharge pipe (209) is connected to a rotary drum mud-water separation device (210), the mud outlet end of the rotary drum mud-water separation device (210) is connected to a crystal inducing carrier storage barrel (211), the crystal inducing carrier storage barrel (211) is connected to the outer end of a first crystal inducing carrier feeding pipe (103) via a crystal inducing carrier delivery pump (212) to realize wet external circulation of the crystal inducing carrier; the crystal inducing carrier storage barrel (211) is connected to the outer end of a second crystal inducing carrier feeding pipe (207) via a screw conveyor (213) to realize dry external circulation of the crystal inducing carrier.

6. The method for removing hardness and salting of high calcium sulfate type wastewater by calcium sulfate circulation induction crystallization as claimed in claim 4, characterized in that: The inner circulation cylinder (203) is a variable outer diameter structure. The lower outer diameter of the inner circulation cylinder (203) is the same as that of the inner cylinder (202), the upper outer diameter of the inner circulation cylinder (203) is larger than the outer diameter of the inner cylinder (202), and the inner cylinder (202) is located in the upper part of the inner circulation cylinder (203).

7. The method for removing hardness and desalting by calcium sulfate circulation induced crystallization for high calcium sulfate type wastewater as claimed in claim 4, characterized in that: A mixing and stirring motor (105) is arranged on the top of the mixing tank body (101), and the mixing and stirring motor (105) drives a mixing and stirring device (106) located in the mixing tank body (101); A top stirring motor (214) is installed on the top of the middle cylinder (204), and the top stirring motor (214) drives an upper stirrer (215) located in the inner cylinder (202) and the inner circulation cylinder (203); A bottom stirring motor (216) is installed at the outer bottom of the outer cylinder (201), and the bottom stirring motor (216) drives a lower stirrer (217) located at the inner bottom of the outer cylinder (201).

8. The method for removing hardness and salting of high calcium sulfate type wastewater by calcium sulfate circulation induction crystallization as claimed in claim 4, characterized in that: An annular water storage tank (218) is provided on the top inner wall of the outer cylinder (201), and the annular water storage tank (218) is connected to the second water outlet pipe (208).

9. The method for removing hardness and salting of high calcium sulfate type wastewater by calcium sulfate circulation induction crystallization as claimed in claim 4, characterized in that: The bottom of the inner circulation cylinder (203) is connected to a crystal inducing carrier exhaust pipe (219).

10. The method for removing hardness and salt from high calcium sulfate type wastewater by calcium sulfate circulation induction crystallization as claimed in claim 4, characterized in that: A first supporting base (107) is disposed at the bottom of the mixing tank body (101); and a second supporting base (220) is disposed at the bottom of the outer cylinder (201).

Images