Resource utilization method and system of mirabilite tailings

Abstract

According to the resource utilization method and system for the mirabilite tailings, through three-stage countercurrent washing and filtering operation, the washing effect of the mirabilite tailings is remarkably improved, the utilization efficiency of the mirabilite tailings is improved, water resource consumption is reduced, secondary solid waste is avoided, and the environmental influence is relieved. Effective utilization of mirabilite tailing resources and environmental protection are promoted.

Description

Technical Field

[0001] The present invention relates to the technical field of resource utilization of tailings, and more specifically, to a resource utilization method and system of mirabilite tailings. Background Art

[0002] Glauber's salt, its main chemical composition is sodium sulfate (Na2SO4), so Glauber's salt minerals can also be called sodium sulfate minerals, which cover a variety of mineral types such as Glauber's salt, calcium Glauber's salt, anhydrous Glauber's salt, etc. Glauber's salt mineral resources have important applications in industry, mainly used to produce chemical raw materials such as alum (anhydrous sodium sulfate with a purity of more than 99%), alkali sulfide and sodium silicate; these products are widely used in many fields such as chemical industry, light industry, textile, building materials and medicine. Among them, calcium Glauber's salt mine is a sedimentary salt deposit, and its main component is the complex salt calcium Glauber's salt (Na2SO4·CaSO4); the content of sodium sulfate (Na2SO4) in this type of mineral is about 17% to 44%, and the content of calcium sulfate (CaSO4) is about 36% to 41%, in addition to a part of water-insoluble matter. At present, the mining of calcium glauberite generally adopts the leaching method based on the physical and chemical water dissolution principle, that is, the mineral is first dissolved in the liquid phase, and then the solid-liquid separation operation is performed to obtain the sodium sulfate leaching solution; after the production of glauberite by leaching mining, a large amount of tailings will be generated, the main chemical component of which is gypsum, the quality grade is close to the fourth-grade gypsum, and contains some glauberite. At present, most companies directly dump these tailings, failing to give full play to the potential value of tailings, resulting in a waste of resources. my country is a country rich in calcium glauberite resources, and the amount of glauberite tailings produced each year is extremely large. If these tailings can be used reasonably, it will not only help to improve resource utilization and reduce environmental pollution, but also bring new economic growth points to related industries; therefore, the development of efficient and environmentally friendly tailings comprehensive utilization technology is of great significance to achieving sustainable development goals.

[0003] Chinese patent publication number CN 115849406 A discloses a sodium sulfate leaching process for a Glauber's salt tailings yard, comprising the following steps: setting a mud collection pool next to the Glauber's salt tailings yard and opening a drainage ditch next to the bottom; opening a leaching pit on the yard and injecting water to leaching the Glauber's salt tailings, and injecting water at intervals during leaching; flushing the bottom of the yard with a water gun to mix the seepage liquid with the mud and flow into the drainage ditch; the liquid in the drainage ditch flows into the mud collection pool and settles naturally, and then the upper clear liquid is extracted to obtain crude nitrate water. This technology dissolves sodium sulfate through the leaching-seepage process to obtain crude nitrate water, hoping to utilize Glauber's salt tailings resources; however, the interval time during the leaching process is long (such as 12 hours), which may lead to low overall production efficiency and difficulty in meeting the needs of large-scale rapid production; moreover, flushing with a water gun may cause secondary pollution problems such as dust, which may cause certain pressure on the environment.

[0004] Chinese patent publication number CN 118439805 A discloses an application of pretreated mirabilite tailings in the preparation of building materials and related building materials. In terms of raw material pretreatment, wet ball milling, water immersion washing, filter pressing and other processes are used to remove the remaining mirabilite in the mirabilite tailings. Experimental data show that the low-carbon cementitious material prepared using the pretreated mirabilite tailings has reasonable initial and final setting times, high strength, and good water resistance. The bulk density, crushing value and sphericity of the synthetic sand meet the relevant standards, and the performance of the two is up to standard when mixed for mortar and other products. This technology enables the utilization rate of mirabilite tailings to reach 90%, realizing the resource utilization of solid waste; however, the pretreatment of raw materials may consume a large amount of water resources and produce a certain amount of wastewater. If it is not handled properly, it will cause water resource waste and environmental pollution; in addition, in terms of product performance, although various indicators meet the current standards, compared with some traditional high-quality building materials, there may be room for improvement in long-term durability and extreme environmental adaptability.

[0005] Therefore, designing a method that can comprehensively utilize the mirabilite tailings, recover the sodium sulfate product, improve the utilization efficiency of the mirabilite tailings, reduce the processing cost, and meet the requirements of clean production has become a difficult problem that needs to be overcome in this field. Summary of the invention

[0006] In view of the defects existing in the prior art, the purpose of the present invention is to provide a method and system for resource utilization of Glauber's salt tailings. Through three-stage countercurrent washing and filtration operations, the washing effect of Glauber's salt tailings is significantly improved, the utilization efficiency of Glauber's salt tailings is improved, the water resource consumption is reduced, the generation of secondary solid waste is avoided, the environmental impact is reduced, and the effective utilization of Glauber's salt tailings resources and environmental protection are promoted.

[0007] To achieve the above object, the present invention adopts the following technical scheme: a method for resource utilization of mirabilite tailings, comprising the following steps:

[0008] A resource utilization method of mirabilite tailings, using a three-stage countercurrent washing method, specifically comprising the following steps:

[0009] S1, primary water washing, crushing the mirabilite tailings and putting them into the first-stage mixing tank for primary pulping, using the secondary filtrate after the secondary filtration as pulping water, and after the pulping is completed, sending the obtained primary slurry into the plate and frame filter press for primary filtration to obtain the primary filtrate and the primary filter cake;

[0010] S2, secondary water washing, the primary filter cake is put into the second-stage mixing tank for secondary pulping, and the third-stage filtrate after the third-stage filtration is used as pulping water. After the pulping is completed, the obtained secondary slurry is sent to the plate and frame filter press for secondary filtration to obtain the secondary filtrate and the secondary filter cake;

[0011] S3, three-stage water washing, the second-stage filter cake is put into the third-stage mixing tank for three-stage pulping, and clean water is used as pulping water. After the pulping is completed, the obtained three-stage slurry is sent to the plate and frame filter press for three-stage filtration to obtain the three-stage filtrate and the three-stage filter cake;

[0012] S4, collect the tertiary filter cake and the primary filtrate with conductivity ≥105ms / cm.

[0013] Preferably, in step S1:

[0014] The particle size of the crushed mirabilite tailings is less than 60 mesh;

[0015] When the conductivity of the primary filtrate is less than 105 ms / cm, the primary filtrate is returned to the primary water washing process and used as pulping water;

[0016] The moisture content of the primary filter cake is 21-26%.

[0017] Preferably, in the steps S1, S2 and S3: during the primary pulping, secondary pulping and tertiary pulping processes, the rotation speed of the stirring paddle used for pulping is not less than 100 rpm, the liquid-to-solid ratio is 2:1 to 4:1, and the pulping time is not less than 30 min.

[0018] Preferably, in steps S1, S2, and S3: during the primary filtration, secondary filtration, and tertiary filtration processes, a diaphragm pneumatic pump and an air compressor are used to deliver the slurry to a plate and frame filter press, the air pressure of the diaphragm pneumatic pump is not less than 0.5 MPa, and the filtration time of the plate and frame filter press is not less than 10 min.

[0019] Preferably, in step S4:

[0020] The third-stage filter cake is used as a tailings product, and its sodium sulfate content is ≤1.7% and its water content is 21-26%;

[0021] The primary filtrate with a conductivity of ≥105 ms / cm is used as a sodium sulfate concentrated solution product, and the primary filtrate is used to prepare glauber salt.

[0022] The second aspect of the present invention provides a resource utilization system of mirabilite tailings, comprising:

[0023] The mirabilite tailings crushing unit is used to crush the mirabilite tailings;

[0024] A three-stage countercurrent water washing device comprises three pulping and filtering devices arranged in series; the pulping and filtering devices comprise a pulping unit and a filtering unit connected to a pulping liquid outlet of the pulping unit; a filter cake outlet of a filtering unit of a previous-stage pulping and filtering device is connected to a feed inlet of a pulping unit of a subsequent-stage pulping and filtering device, and a filtrate outlet of a filtering unit of the subsequent-stage pulping and filtering device is connected to a pulping water inlet of a pulping unit of a previous-stage pulping and filtering device; and a pulping water inlet of a pulping unit of a third-stage pulping and filtering device is connected to clean water;

[0025] The product unit includes a sodium sulfate product storage device connected to the filtrate outlet of the filter unit of the first-stage pulping and filtering device and a tailings product storage device connected to the filter cake outlet of the filter unit of the third-stage pulping and filtering device;

[0026] The resource utilization system of the mirabilite tailings is used to execute the resource utilization method of the mirabilite tailings as described in the first aspect of the present invention.

[0027] Preferably, the pulping unit comprises a feeder and a stirring tank, the feeder is connected to the feed port of the stirring tank, a pulping water inlet is provided on the stirring tank, a stirring paddle is provided on the top of the stirring tank, and the stirring paddle is driven by a motor.

[0028] Preferably, the filtration unit includes a diaphragm pneumatic pump, an air compressor connected to the diaphragm pneumatic pump and a plate and frame filter press, the inlet of the diaphragm pneumatic pump is connected to the slurry outlet of the stirring tank, and the outlet of the diaphragm pneumatic pump is connected to the feed port of the plate and frame filter press.

[0029] Preferably, the filtrate outlet of the filter unit of the first-stage pulping filter device is connected to the sodium sulfate product storage device through a filtrate pipeline; the filtrate pipeline is provided with a conductivity detector for detecting the conductivity of the first filtrate;

[0030] The filtrate pipeline between the conductivity detector and the sodium sulfate product storage device is connected with a filtrate branch pipe connected to the pulping water inlet of the pulping unit of the first-stage pulping filtration device.

[0031] The effects of the present invention are as follows:

[0032] 1. The present invention significantly improves the washing effect through multi-stage washing and separation operations, effectively reduces the content of mirabilite in mirabilite tailings while reducing the waste of water resources, and effectively recovers mirabilite for subsequent production activities;

[0033] 2. The present invention produces a sodium sulfate concentrated solution product and a tailings product from the mirabilite tailings resources, and also solves the problem of huge water resource consumption and large-scale loss of sodium sulfate components in the mirabilite tailings washing process;

[0034] 3. The present invention significantly increases the sodium sulfate concentration in the sodium sulfate concentrated solution product and reduces the sodium sulfate content in the tailings product; improves the utilization efficiency of mirabilite tailings, reduces water resource consumption, avoids the generation of secondary solid waste, and reduces environmental impact; the present invention demonstrates good economic benefits and market application prospects, and supports the realization of sustainable development goals. This method not only improves the quality of the product, but also promotes the effective utilization of resources and environmental protection;

[0035] 4. The present invention can increase the concentration of the sodium sulfate solution in the washing filtrate to near saturation through three-stage countercurrent washing, thereby improving the utilization efficiency of sodium sulfate and significantly reducing the concentration of sodium sulfate in the washing filter cake, thereby improving the building material utilization performance of the washing filter cake;

[0036] 5. The mirabilite tailings of the present invention can be washed with three-stage countercurrent water to obtain a sodium sulfate solution product and a water-washed filter cake product. The sodium sulfate solution product can be used to make sodium sulfate, and the water-washed filter cake can be used for building materials, thereby realizing the recycling of solid waste resources, improving the economic value of tailings, and promoting circular economy.

[0037] 6. The system structure and process flow used in the present invention are simple, and can be miniaturized and skid-mounted, which is conducive to small-scale production;

[0038] 7. The system energy consumption and water consumption used in the present invention are low, which is in line with energy conservation and emission reduction, and 5. No three wastes are generated in the water washing production process, which is in line with green production. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 The present invention is a flow chart of the resource utilization method of mirabilite tailings. DETAILED DESCRIPTION

[0040] In order to better understand the above technical solution of the present invention, the technical solution of the present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0041] Combination Figure 1 As shown, the present invention provides a resource utilization method of mirabilite tailings, which adopts a three-stage countercurrent washing method and specifically includes the following steps:

[0042] S1, primary water washing, crushing the mirabilite tailings and putting them into the first-stage mixing tank for primary pulping, using the secondary filtrate after the secondary filtration as pulping water, and after the pulping is completed, sending the obtained primary slurry into the plate and frame filter press for primary filtration to obtain the primary filtrate and the primary filter cake;

[0043] This step is a primary water washing process. The mirabilite tailings are first crushed to a particle size of less than 60 meshes, and then put into the first-stage stirring tank of the pulping unit of the first-stage pulping and filtering device for primary pulping. The secondary filtrate after the secondary filtration is used as pulping water. The pulping operation is completed under the stirring of a stirring paddle. The rotation speed of the stirring paddle used for pulping is not less than 100rpm, the liquid-solid ratio is 2:1-4:1, and the pulping time is not less than 30min. After the pulping is completed, a primary slurry containing sodium sulfate is obtained, and then the primary slurry is sent to the plate and frame filter press of the filtering unit of the first-stage pulping and filtering device for primary filtration. The primary slurry is sent to the plate and frame filter press by a diaphragm pneumatic pump and an air compressor. The air pressure of the diaphragm pneumatic pump is not less than 0.5MPa, and the filtration time of the plate and frame filter press is not less than 10min. Until the water outlet stops flowing and the feeding stops; after the first-level filtration is completed, the first-level filtrate and the first-level filter cake are obtained; at this time, the conductivity of the first-level filtrate is detected. When the conductivity of the first-level filtrate is less than 105ms / cm, the first-level filtrate returns to the first-level water washing process and is used as pulping water; when the conductivity of the first-level filtrate is ≥105ms / cm, it is considered that the sodium sulfate concentration of the first-level filtrate is close to saturation, and the first-level filtrate is the sodium sulfate concentrated solution product.

[0044] S2, secondary water washing, the primary filter cake is put into the second-stage mixing tank for secondary pulping, and the third-stage filtrate after the third-stage filtration is used as pulping water. After the pulping is completed, the obtained secondary slurry is sent to the plate and frame filter press for secondary filtration to obtain the secondary filtrate and the secondary filter cake;

[0045] This step is a secondary water washing process. The primary filter cake is put into the second-stage stirring tank of the pulping unit of the second-stage pulping and filtering device for secondary pulping. The third-stage filtrate after the third-stage filtration is used as pulping water. The pulping operation is completed under the stirring of the stirring paddle. The speed of the stirring paddle used for pulping is not less than 100rpm, the liquid-solid ratio is 2:1-4:1, and the pulping time is not less than 30min. After the pulping is completed, the secondary slurry is obtained, and then the secondary slurry is sent to the plate-frame filter press of the filtering unit of the second-stage pulping and filtering device for secondary filtration. The secondary slurry is sent to the plate-frame filter press by a diaphragm pneumatic pump and an air compressor. The air pressure of the diaphragm pneumatic pump is not less than 0.5MPa, and the filtration time of the plate-frame filter press is not less than 10min. Until the water outlet is cut off and the feeding is stopped, the secondary filtrate and the secondary filter cake are obtained.

[0046] S3, three-stage water washing, the second-stage filter cake is put into the third-stage mixing tank for three-stage pulping, and clean water is used as pulping water. After the pulping is completed, the obtained three-stage slurry is sent to the plate and frame filter press for three-stage filtration to obtain the three-stage filtrate and the three-stage filter cake;

[0047] This step is a three-stage water washing process. The second-stage filter cake is put into the third-stage stirring tank of the pulping unit of the third-stage pulping and filtering device for three-stage pulping. Clean water is used as pulping water. The pulping operation is completed under the stirring of the stirring paddle. The speed of the stirring paddle used for pulping is not less than 100rpm, the liquid-solid ratio is 2:1-4:1, and the pulping time is not less than 30min. After the pulping is completed, the third-stage slurry is obtained, and then the third-stage slurry is sent to the plate-frame filter press of the filtering unit of the third-stage pulping and filtering device for three-stage filtration. The third-stage slurry is sent to the plate-frame filter press by a diaphragm pneumatic pump and an air compressor. The air pressure of the diaphragm pneumatic pump is not less than 0.5MPa, and the filtration time of the plate-frame filter press is not less than 10min. Until the water outlet is cut off and the feeding is stopped, the third-stage filtrate and the third-stage filter cake are obtained.

[0048] S4, collect the tertiary filter cake and the primary filtrate with conductivity ≥105ms / cm.

[0049] This step is mainly to collect the product and detect the conductivity of the first-level filtrate. When the conductivity of the first-level filtrate is ≥105ms / cm, it is considered that the sodium sulfate concentration of the first-level filtrate is close to saturation, and the first-level filtrate is a sodium sulfate concentrated solution product. The sodium sulfate content of the sodium sulfate concentrated solution product is ≥15%, which can be used to make glauber salt. The third-level filter cake is collected as a tailings product, which can be used for building materials. The sodium sulfate content of the tailings product is ≤1.7%, and the water content is 21-26%.

[0050] The above steps adopt a three-stage countercurrent washing method, in which the pulping operation, filtering operation, and the conveying operation of pulping water and filter cake are all operated in batches, and finally a sodium sulfate concentrated solution product and a tailings product are prepared from the mirabilite tailings, which significantly improves the concentration of the sodium sulfate concentrated solution product (the concentration of sodium sulfate reaches 15-16%) and reduces the sodium sulfate content in the tailings product (the content of sodium sulfate is 1.1-1.7%).

[0051] Combination Figure 1As shown, the present invention also provides a resource utilization system of mirabilite tailings, which is used to execute the resource utilization method of mirabilite tailings mentioned above. The resource utilization system of mirabilite tailings includes a mirabilite tailing crushing unit, a three-stage countercurrent washing device and a product unit. The mirabilite tailing crushing unit is used to crush the mirabilite tailings; the three-stage countercurrent washing device includes three pulping and filtering devices arranged in series; the pulping and filtering device includes a pulping unit and a filtering unit connected to the pulping outlet of the pulping unit; the filter cake outlet of the filtering unit of the previous pulping and filtering device is connected to the feed inlet of the pulping unit of the next pulping and filtering device, and the filtrate outlet of the filtering unit of the next pulping and filtering device is connected to the pulping water inlet of the pulping unit of the previous pulping and filtering device; the pulping water inlet of the pulping unit of the third pulping and filtering device is connected to clean water. The product unit includes a sodium sulfate product storage device connected to the filtrate outlet of the filtering unit of the first pulping and filtering device and a tailings product storage device connected to the filter cake outlet of the filtering unit of the third pulping and filtering device. The resource utilization system of mirabilite tailings of the present invention is composed of three sets of pulping and filtering devices in series. After each stage of filtration, the filtrate is sent to the previous stage of pulping, and the filter cake is sent to the next stage of pulping. The target products are the first stage filtrate and the third stage filter cake.

[0052] The pulping unit comprises a feeder and a stirring tank. The feeder is connected to the feeding port of the stirring tank. The stirring tank is provided with a pulping water inlet. The top of the stirring tank is provided with a stirring paddle driven by a motor.

[0053] The filtration unit includes a diaphragm pneumatic pump, an air compressor connected to the diaphragm pneumatic pump, and a plate-frame filter press. The inlet of the diaphragm pneumatic pump is connected to the slurry outlet of the mixing tank, and the outlet of the diaphragm pneumatic pump is connected to the feed port of the plate-frame filter press. The plate-frame filter press consists of a filter plate, a filter frame, and a filter cloth, and pressure is applied by a hydraulic system to help filter out the filtrate.

[0054] The filtrate outlet of the filtering unit of the first-stage pulping and filtering device is connected to the sodium sulfate product storage device through a filtrate pipeline; a conductivity detector for detecting the conductivity of the first filtrate is provided on the filtrate pipeline; the filtrate pipeline between the conductivity detector and the sodium sulfate product storage device is connected to a filtrate branch pipe connected to the pulping water inlet of the pulping unit of the first-stage pulping and filtering device, and when the conductivity of the primary filtrate is less than 105ms / cm, the primary filtrate is recycled to the pulping unit of the first-stage pulping and filtering device through the filtrate branch pipe for primary pulping.

[0055] Example 1

[0056] refer to Figure 1 As shown, the present embodiment provides a method for resource utilization of mirabilite tailings, comprising the following steps:

[0057] (1) Primary pulping: The mirabilite tailings crushed to a particle size of 60 mesh are put into the first-stage mixing tank for pulping. During the pulping process, the secondary filtrate is used as pulping water, the liquid-to-solid ratio is 3:1, the stirring paddle is stirred at a speed of 120 rpm, and the pulping is carried out for 30 minutes to fully dissolve the sodium sulfate in the mirabilite tailings;

[0058] (2) Primary filtration: After pulping is completed, the slurry is sent to the plate and frame filter press for filtration through a diaphragm pneumatic pump and an air compressor. The filtration process continues until the outlet is cut off. The conductivity of the filtrate after filtration is about 105ms / cm, and the moisture content of the filter cake is about 21%. The primary filtrate is collected for product use, and the primary filter cake is used for secondary pulping;

[0059] (3) Secondary pulping: The first-stage filter cake is put into the second-stage mixing tank for pulping. The third-stage filtrate is used as pulping water in the pulping process, with a liquid-to-solid ratio of 3:1, and the stirring paddle is stirred at a speed of 120 rpm for 30 minutes;

[0060] (4) Secondary filtration: After pulping, the pulp is sent to the plate and frame filter press for filtration. The conductivity of the filtrate after filtration is about 40ms / cm, and the moisture content of the filter cake is about 20%. The secondary filtrate is collected for primary pulping, and the secondary filter cake is used for tertiary pulping;

[0061] (5) Three-stage pulping: The second-stage filter cake is put into the third-stage mixing tank for pulping. The third-stage filtrate is used as pulping water in the pulping process, with a liquid-to-solid ratio of 3:1, and the stirring paddle is stirred at a speed of 120 rpm for 30 minutes;

[0062] (6) Tertiary filtration: After pulping, the product is sent to a plate and frame filter press for filtration. The conductivity of the filtrate after filtration is about 8ms / cm, and the moisture content of the tertiary filter cake is about 21%. The tertiary filtrate is collected for secondary pulping, and the tertiary filter cake is used for the product.

[0063] In this embodiment, the first-stage filtrate with a conductivity of about 105ms / cm is collected as a sodium sulfate concentrated solution product, in which the concentration of sodium sulfate is 15.4%, which can be used to make glauber salt; the third-stage filter cake is collected as a tailings product, which has a sodium sulfate content of 1.4%, which can be used for building materials.

[0064] Example 2

[0065] refer to Figure 1 As shown, the present embodiment provides a method for resource utilization of mirabilite tailings, comprising the following steps:

[0066] (1) Primary pulping: The mirabilite tailings crushed to a particle size of 80 mesh are put into the first-stage mixing tank for pulping. During the pulping process, the secondary filtrate is used as pulping water, the liquid-to-solid ratio is 2:1, the stirring paddle is stirred at a speed of 120 rpm, and the pulping is carried out for 60 minutes to fully dissolve the sodium sulfate in the mirabilite tailings;

[0067] (2) Primary filtration: After pulping is completed, the slurry is sent to the plate and frame filter press for filtration through a diaphragm pneumatic pump and an air compressor. The filtration process continues until the outlet is cut off. The conductivity of the filtrate after filtration is about 110ms / cm, and the moisture content of the filter cake is about 23%. The filtrate is collected for product use, and the filter cake is used for secondary pulping;

[0068] (3) Secondary pulping: The first filter cake is put into the second stage mixing tank for pulping. The third stage filtrate is used as pulping water in the pulping process, with a liquid-to-solid ratio of 2:1, and the stirring paddle is stirred at a speed of 120 rpm for 60 minutes;

[0069] (4) Secondary filtration: After pulping, the pulp is sent to the plate and frame filter press for filtration. The conductivity of the filtrate after filtration is about 55ms / cm, and the moisture content of the filter cake is about 24%. The filtrate is collected for primary pulping, and the filter cake is used for tertiary pulping;

[0070] (5) Three-stage pulping: The second-stage filter cake is put into the third-stage mixing tank for pulping. The third-stage filtrate is used as pulping water in the pulping process, with a liquid-to-solid ratio of 2:1, and the stirring paddle is stirred at a speed of 120 rpm for 60 minutes;

[0071] (6) Tertiary filtration: After pulping, the product is sent to a plate and frame filter press for filtration. The conductivity of the filtrate is about 12ms / cm, and the moisture content of the filter cake is about 24%. The filtrate is collected for secondary pulping, and the filter cake is used for the product.

[0072] In this embodiment, the first-stage filtrate with a conductivity of about 110 ms / cm is collected as a sodium sulfate concentrated solution product, in which the concentration of sodium sulfate is 15.8%, which can be used to make glauber salt; the third-stage filter cake is collected as a tailings product, which has a sodium sulfate content of 1.2%, which can be used for building materials.

[0073] Those skilled in the art should recognize that the above embodiments are only used to illustrate the present invention, and are not intended to limit the present invention. As long as they are within the spirit of the present invention, any changes or modifications to the above embodiments will fall within the scope of the claims of the present invention.

Claims

1. A method for resource utilization of mirabilite tailings, characterized in that: The three-stage countercurrent washing method is adopted. The following steps are involved: S1, primary water washing, crushing the mirabilite tailings and putting them into the first-stage mixing tank for primary pulping, using the secondary filtrate after the secondary filtration as pulping water, and after the pulping is completed, sending the obtained primary slurry into the plate and frame filter press for primary filtration to obtain the primary filtrate and the primary filter cake; S2, secondary water washing, the primary filter cake is put into the second-stage mixing tank for secondary pulping, and the third-stage filtrate after the third-stage filtration is used as pulping water. After the pulping is completed, the obtained secondary slurry is sent to the plate and frame filter press for secondary filtration to obtain the secondary filtrate and the secondary filter cake; S3, three-stage water washing, the second-stage filter cake is put into the third-stage mixing tank for three-stage pulping, and clean water is used as pulping water. After the pulping is completed, the obtained three-stage slurry is sent to the plate and frame filter press for three-stage filtration to obtain the three-stage filtrate and the three-stage filter cake; S4, collect the tertiary filter cake and the primary filtrate with conductivity ≥105ms / cm.

2. The resource utilization method of mirabilite tailings according to claim 1, characterized in that: In step S1: The particle size of the crushed mirabilite tailings is less than 60 mesh; When the conductivity of the primary filtrate is less than 105 ms / cm, the primary filtrate is returned to the primary water washing process and used as pulping water; The moisture content of the primary filter cake is 21-26%.

3. The resource utilization method of mirabilite tailings according to claim 1, characterized in that: In the steps S1, S2 and S3: during the first-stage pulping, the second-stage pulping and the third-stage pulping, the rotation speed of the stirring paddle used for pulping is not less than 100 rpm, the liquid-to-solid ratio is 2:1 to 4:1, and the pulping time is not less than 30 minutes.

4. The resource utilization method of mirabilite tailings according to claim 1, characterized in that: In the steps S1, S2 and S3: during the primary filtration, secondary filtration and tertiary filtration processes, a diaphragm pneumatic pump and an air compressor are used to deliver the slurry into a plate and frame filter press, the air pressure of the diaphragm pneumatic pump is not less than 0.5 MPa, and the filtration time of the plate and frame filter press is not less than 10 min.

5. The resource utilization method of mirabilite tailings according to claim 1, characterized in that: In step S4: The third-stage filter cake is used as a tailings product, and its sodium sulfate content is ≤1.7% and its water content is 21-26%; The primary filtrate with a conductivity of ≥105 ms / cm is used as a sodium sulfate concentrated solution product, and the primary filtrate is used to prepare glauber salt.

6. A resource utilization system of mirabilite tailings, characterized by: include The mirabilite tailings crushing unit is used to crush the mirabilite tailings; A three-stage countercurrent water washing device comprises three pulping and filtering devices arranged in series; the pulping and filtering devices comprise a pulping unit and a filtering unit connected to a pulping liquid outlet of the pulping unit; a filter cake outlet of a filtering unit of a previous-stage pulping and filtering device is connected to a feed inlet of a pulping unit of a subsequent-stage pulping and filtering device, and a filtrate outlet of a filtering unit of the subsequent-stage pulping and filtering device is connected to a pulping water inlet of a pulping unit of a previous-stage pulping and filtering device; and a pulping water inlet of a pulping unit of a third-stage pulping and filtering device is connected to clean water; The product unit includes a sodium sulfate product storage device connected to the filtrate outlet of the filter unit of the first-stage pulping and filtering device and a tailings product storage device connected to the filter cake outlet of the filter unit of the third-stage pulping and filtering device; The resource utilization system of the mirabilite tailings is used to execute the resource utilization method of the mirabilite tailings as claimed in any one of claims 1 to 5.

7. The resource utilization system of mirabilite tailings according to claim 6 is characterized in that: The pulping unit comprises a feeder and a stirring tank, wherein the feeder is connected to the feed port of the stirring tank, a pulping water inlet is arranged on the stirring tank, and a stirring paddle is arranged on the top of the stirring tank, and the stirring paddle is driven by a motor.

8. The resource utilization system of mirabilite tailings according to claim 7, characterized in that: The filtration unit includes a diaphragm pneumatic pump, an air compressor connected to the diaphragm pneumatic pump, and a plate-frame filter press. The inlet of the diaphragm pneumatic pump is connected to the slurry outlet of the stirring tank, and the outlet of the diaphragm pneumatic pump is connected to the feed port of the plate-frame filter press.

9. The resource utilization system of mirabilite tailings according to claim 1, characterized in that: The filtrate outlet of the filter unit of the first-stage pulping filter device is connected to the sodium sulfate product storage device through a filtrate pipeline; the filtrate pipeline is provided with a conductivity detector for detecting the conductivity of the first filtrate; The filtrate pipeline between the conductivity detector and the sodium sulfate product storage device is connected with a filtrate branch pipe connected to the pulping water inlet of the pulping unit of the first-stage pulping filtration device.

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