Carnallite recycling device and carnallite recycling method

Abstract

The invention discloses a carnallite recycling device and a carnallite recycling method. The carnallite recycling device comprises a crushing, screening and dissolving system, a hardness, silicon and fluorine removal system, a primary filter pressing system, an organic matter adsorption system, a secondary filter pressing system, a sand filtering system, a freezing crystallization system, a filtering system, a sodium chloride evaporative crystallization system and a sodium nitrate cold separation crystallization system which are connected in sequence. According to the carnallite recycling device and method, the problem that nitrate radicals are difficult to remove can be solved, and a high-purity sodium nitrate product is obtained, so that dissolved carnallite enters the freezing crystallization device, the sulfate radical concentration of frozen clear liquid can be controlled, then the carnallite enters the nanofiltration system, and the purity of sodium chloride can be guaranteed; and high-purity sodium nitrate can be separated from the finally enriched sodium nitrate through a cold separation method, so that multi-component carnallite can be recycled to the maximum extent.

Description

Technical Field

[0001] The present application relates to the field of water treatment technology, and in particular to a device and method for recycling miscellaneous salts. Background Art

[0002] At present, in the zero-discharge treatment process of high-salinity wastewater, the salt in the concentrated water is mainly precipitated in the form of sodium chloride, sodium sulfate and miscellaneous salts. Sodium chloride and sodium sulfate can be directly recycled as resources if they meet the industrial crystal salt standards, but there are still many projects where the purity of sodium chloride and sodium sulfate produced cannot meet the industrial crystal salt standards, thus limiting the further use of these low-purity crystal salts such as sodium chloride and sodium sulfate.

[0003] In addition to sodium chloride and sodium sulfate, the miscellaneous salts also contain relatively high organic matter, nitrate, hardness, silicon dioxide and other impurities, which cannot be directly utilized. At present, in the existing technology, the miscellaneous salts are mainly disposed by solidification landfill, which not only occupies a large amount of land resources, but also causes serious pollution of land and underground resources if not properly disposed, posing a great threat to human life and living environment.

[0004] At present, sodium chloride, sodium sulfate and other impurities are often removed by pyrolysis. The pyrolysis method usually uses electricity, natural gas, biomass, etc. to provide energy, and the pyrolysis temperature is generally above 400°C, so the pyrolysis method has high energy consumption. When dealing with multi-component impurities, if sodium nitrate is present, it will melt and stick to the pyrolysis device during the organic matter removal process, thereby affecting the stable operation of the pyrolysis device. At present, there is still no better removal method for sodium nitrate, and the electrochemical removal of nitrate is still in the theoretical stage. Although nitrate can be converted into nitrogen or ammonia in experiments, it is still limited by the catalyst and cannot reach the scale of industrial application.

[0005] When recycling the miscellaneous salts, the source of the miscellaneous salts is not fixed, so the ratio of sodium chloride and sodium sulfate in the miscellaneous salts cannot be guaranteed to fluctuate within a certain range, thus limiting the stable operation of the nanofiltration process. It can be seen that the harmless treatment and resource utilization of the by-product miscellaneous salts in the zero-discharge treatment process of high-salinity wastewater is still a major problem that the industry needs to solve urgently. Summary of the invention

[0006] Based on this, it is necessary to provide a miscellaneous salt resource device. The miscellaneous salt resource device of the present invention provides a new idea and method for solving the industrial application of multi-component miscellaneous salts containing sodium chloride, sodium sulfate, sodium nitrate, etc., and realizes the maximum degree of miscellaneous salt resource utilization with good resource utilization effect.

[0007] An embodiment of the present application provides a device for recycling miscellaneous salts.

[0008] A device for recycling impure salts comprises a crushing, screening and dissolving system, a hardness removal, silicon removal and fluorine removal system, a primary filter press system, an organic matter adsorption system, a secondary filter press system, a sand filtration system, a freezing crystallization system, a filtration system, a sodium chloride evaporation crystallization system and a sodium nitrate cold precipitation crystallization system, which are connected in sequence. The crushing, screening and dissolving system is used to break up, crush and dissolve multi-component impure salts. The hardness removal, silicon removal and fluorine removal system removes fluorine, silicon and hardness from the dissolved solution of the crushing, screening and dissolving system by adding reagents. The primary filter press system is used to perform a first filter press treatment on the reaction solution from the hardness removal, silicon removal and fluorine removal system. The organic matter adsorption system is used to add liquid resin and adsorbent for The filtrate from the primary filter press system is subjected to adsorption treatment to remove part of organic matter. The secondary filter press system is used to perform a first filter press treatment on the reaction liquid from the organic matter adsorption system. The sand filtration system is used to filter the filtrate from the secondary filter press system. The freezing crystallization system is used to freeze and crystallize the filtrate from the sand filtration system to precipitate sodium sulfate. The filtration system is used to filter the frozen clear liquid of the freezing crystallization system. The produced water of the filtration system enters the sodium chloride evaporation crystallization system for evaporation and crystallization to produce sodium chloride. The sodium chloride mother liquor of the sodium chloride evaporation and crystallization system enters the sodium nitrate cold precipitation crystallization system for cold precipitation and crystallization to obtain sodium nitrate.

[0009] In some embodiments, the filtration system includes an ultrafiltration system and a nanofiltration system sequentially distributed along the water flow direction, the ultrafiltration system is used to ultrafilter the frozen clear liquid from the freezing crystallization system to intercept most of the suspended matter and unsettled fine salts, the ultrafiltration water produced by the ultrafiltration system enters the nanofiltration system, the nanofiltration system is used to perform nanofiltration treatment on the ultrafiltration water produced by the ultrafiltration system, and the nanofiltration water containing sodium chloride from the nanofiltration system enters the sodium chloride evaporation crystallization system for evaporation and crystallization to produce sodium chloride;

[0010] The nanofiltration system is also connected to the freezing crystallization system, and the nanofiltration concentrate of the nanofiltration system flows back to the freezing crystallization system, and the sodium sulfate contained in the nanofiltration concentrate of the nanofiltration system is returned to the freezing crystallization system for re-freezing crystallization.

[0011] In some embodiments, the impurity salt resource recovery device further includes a mother liquor impurity removal system, the sodium nitrate cold precipitation crystallization system is further connected to the mother liquor impurity removal system, and the mother liquor impurity removal system is further connected to the crushing, screening and dissolution system;

[0012] The mother liquor impurity removal system is used to remove fine salt with small particle size and some impurities from the sodium nitrate mother liquor from the sodium nitrate cold precipitation crystallization system, and to improve the shape of the sodium nitrate mother liquor by adding a mother liquor improver. The sodium nitrate mother liquor treated by the mother liquor impurity removal system is refluxed to the crushing, screening and dissolution system for circulation.

[0013] In some embodiments, the impure salt resource utilization device also includes a sodium sulfate hot melt crystallization system, which is connected to the frozen crystallization system, and is used to remove crystal water from the sodium sulfate from the frozen crystallization system to form sodium sulfate salt.

[0014] In some embodiments, the impure salt resource utilization device also includes a sodium sulfate centrifugal drying system, which is connected to the sodium sulfate hot melt crystallization system. The sodium sulfate centrifugal drying system is used to centrifugally dry the sodium sulfate from the sodium sulfate hot melt crystallization system to control the water content of the sodium sulfate to be no higher than 4%.

[0015] In some of the embodiments, the impure salt resource utilization device also includes a first fluidized bed, which is connected to the sodium sulfate centrifugal drying system, and the first fluidized bed is used for fluidizing and dehydrating the sodium sulfate from the sodium sulfate centrifugal drying system to control the water content of the sodium sulfate to be no higher than 0.4%.

[0016] In some embodiments, the impure salt resource utilization device also includes a sodium chloride centrifugal drying system, which is connected to the sodium chloride evaporation and crystallization system. The sodium chloride centrifugal drying system is used to centrifugally dry the sodium chloride from the sodium chloride evaporation and crystallization system to control the water content of the sodium chloride to be no higher than 4%.

[0017] In some of the embodiments, the impure salt resource utilization device also includes a second fluidized bed, which is connected to the sodium chloride centrifugal drying system, and the second fluidized bed is used for fluidizing and dehydrating the sodium chloride from the sodium chloride centrifugal drying system to control the water content of the sodium chloride to be no higher than 0.4%.

[0018] In some embodiments, the miscellaneous salt resource utilization device also includes a sodium nitrate centrifugal drying system, which is connected to the sodium nitrate cold crystallization system, and is used to centrifugally dry the sodium nitrate from the sodium nitrate cold crystallization system to control the water content of the sodium nitrate to be no higher than 4%.

[0019] In some of the embodiments, the impure salt resource utilization device also includes a third fluidized bed, which is connected to the sodium nitrate centrifugal drying system, and the third fluidized bed is used for fluidizing and dehydrating the sodium nitrate from the sodium nitrate centrifugal drying system to control the water content of the sodium nitrate to be no higher than 0.4%.

[0020] In some embodiments, the moisture content of the filter cake after the filtration treatment of the primary filter press system is ≤65%, the filter cloth of the primary filter press system is made of 300-400 mesh polyester, and the plate and frame outlet water SS of the primary filter press system is ≤20 mg / L;

[0021] And / or, the moisture content of the filter cake after filtration treatment of the secondary filter press system is ≤65%, the filter cloth of the secondary filter press system is made of 300-400 mesh polyester material, and the plate and frame outlet water SS of the secondary filter press system is ≤20 mg / L.

[0022] In some of the embodiments, the decolorization rate of the liquid resin added in the organic adsorption system is not less than 95%, and the removal rate of organic matter is not less than 70%; the adsorbent added in the organic adsorption system includes powdered activated carbon, and the powdered activated carbon has a particle size of 0.5mm~2mm and the proportion of activated carbon specifications is more than 85%, the iodine adsorption value of the powdered activated carbon is ≥900mg / g, and the liquid resin added in the organic adsorption system and the adsorption efficiency of the adsorbent organic matter are not less than 90%.

[0023] An embodiment of the present application provides a method for recycling miscellaneous salts.

[0024] A method for recycling miscellaneous salts, using the above-mentioned miscellaneous salt recycling device, comprises the following steps:

[0025] Multi-component salts enter the crushing, screening and dissolving system for breaking up, crushing and dissolving;

[0026] Adding reagents to the hardness removal, silicon removal and fluorine removal system to remove fluorine, silicon and hardness from the dissolved solution from the crushing, screening and dissolving system;

[0027] Controlling the primary filter press system to perform a first filter press treatment on the reaction liquid from the hardness removal, silicon removal and fluorine removal system; adding liquid resin and adsorbent to the organic matter adsorption system to perform adsorption treatment on the filtrate from the primary filter press system to remove part of the organic matter;

[0028] Controlling the secondary filter press system to perform a first filter press treatment on the reaction liquid from the organic matter adsorption system; controlling the sand filtration system to perform filtering treatment on the filtrate from the secondary filter press system;

[0029] The freezing crystallization system is controlled to perform freezing crystallization on the filtrate from the sand filtration system to precipitate sodium sulfate; the filtration system is controlled to filter the frozen clear liquid of the freezing crystallization system, the produced water of the filtration system enters the sodium chloride evaporation crystallization system for evaporation crystallization to produce sodium chloride, and the sodium chloride mother liquor of the sodium chloride evaporation crystallization system enters the sodium nitrate cold precipitation crystallization system for cold precipitation crystallization to obtain sodium nitrate.

[0030] In some embodiments, the method for recycling impure salts further satisfies at least one of the following conditions:

[0031] (1) Use a fine crusher to break up and crush the multi-component impure salts that enter the crushing, screening and dissolving system. After vibration screening, the output size is 2mm~4mm;

[0032] (2) The multi-component impure salts enter the crushing, screening and dissolution system for breaking up, crushing and dissolving, and the dissolution concentration is controlled at 25%~35%;

[0033] (3) When adding reagents to the hardness removal, silicon removal and fluorine removal system to remove fluorine, silicon and hardness from the dissolved solution of the crushing, screening and dissolving system, calcium chloride or a defluorinating agent is used to remove fluorine and control the fluoride index to ≤20mg / L;

[0034] (4) When adding reagents to the hardness removal, silicon removal and fluorine removal system to remove fluorine, silicon and hardness from the dissolving solution from the crushing, screening and dissolving system, magnesium oxide or sodium aluminate is used for silicon removal, and the silicon index is controlled to be ≤20mg / L;

[0035] (5) When adding reagents to the hardness removal, silicon removal and fluorine removal system to remove fluorine, silicon and hardness from the dissolved solution from the crushing, screening and dissolving system, sodium carbonate is used for hardness removal to remove the calcium hardness introduced during the addition of reagents and the calcium hardness in the impurities, and the total hardness is controlled to be ≤100 mg / L;

[0036] (6) The freezing crystallization temperature of the freezing crystallization system is controlled to be -5°C to 0°C, most of the sulfate ions in the high-concentration brine of the freezing crystallization system are separated and precipitated in the form of sodium sulfate, and the purity of the sodium sulfate obtained by freezing crystallization is not less than 98.5%;

[0037] (7) Controlling the cold crystallization temperature of the sodium nitrate cold crystallization system to be 5°C to 10°C.

[0038] The above-mentioned miscellaneous salt resource utilization device dissolves the miscellaneous salts and crystallized salts contained in the multi-component miscellaneous salts in water, and captures the organic matter that affects evaporation and crystallization by adding agents, which greatly reduces energy consumption and meets the national energy conservation and consumption reduction initiatives and requirements. The miscellaneous salt resource utilization method of the present application is not limited by the sodium nitrate component in the miscellaneous salts, but also separates the sodium nitrate, which not only solves the problem that nitrate is difficult to remove but also obtains a high-purity sodium nitrate product. Therefore, the present application first puts the dissolved miscellaneous salts into a freezing crystallization device, which can control the sulfate concentration of the frozen clear liquid, and then enters the nanofiltration system to ensure the purity of sodium chloride. For the finally enriched sodium nitrate, high-purity sodium nitrate can be separated by cold analysis, and finally the multi-component miscellaneous salts can be maximized. Resource utilization. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application, and those skilled in the art can obtain other drawings based on these drawings without creative work.

[0040] In order to more completely understand the present application and its beneficial effects, the following description will be given in conjunction with the accompanying drawings. In the following description, the same reference numerals represent the same parts.

[0041] FIG1 is a schematic diagram of a device for recycling miscellaneous salts according to an embodiment of the present invention.

[0042] Description of Reference Numerals

[0043] 10. Miscellaneous salt resource utilization device; 100. Crushing, screening and dissolving system; 200. Hardness, silicon and fluorine removal system; 300. Primary filter press system; 400. Organic matter adsorption system; 500. Secondary filter press system; 600. Sand filtration system; 700. Freeze crystallization system; 800. Ultrafiltration system; 900. Nanofiltration system; 1000. Sodium chloride evaporation crystallization system; 1100. Sodium nitrate cold crystallization system; 1200. Mother liquor impurity removal system; 1300. Sodium sulfate hot melt crystallization system; 1400. Sodium sulfate centrifugal drying system; 1500. Sodium chloride centrifugal drying system; 1600. Sodium nitrate centrifugal drying system. DETAILED DESCRIPTION

[0044] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present invention, so the present invention is not limited by the specific embodiments disclosed below.

[0045] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0046] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0047] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0048] In the description of the present invention, "several" means more than one, "many" means more than two, "greater than", "less than", "exceed", etc. are understood to exclude the number itself, and "above", "below", "within", etc. are understood to include the number itself. If there is a description of "first" or "second", it is only used for the purpose of distinguishing the technical features, and cannot be understood as indicating or implying the relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0049] In this article, "optionally", "optional", "optional" means optional, that is, it means to be selected from any of the two parallel solutions of "yes" or "no". If there are multiple "optional" in a technical solution, unless otherwise specified and there is no contradiction or mutual restriction, each "optional" is independent. In this application, the descriptions such as "optionally contain" and "optionally include" mean "contain or not contain".

[0050] In the present application, when it comes to a numerical interval (i.e., a numerical range), unless otherwise specified, the distribution of the optional numerical values ​​in the numerical interval is considered to be continuous, and includes the two numerical endpoints (i.e., the minimum and maximum values) of the numerical interval, and each numerical value between the two numerical endpoints. Unless otherwise specified, when the numerical interval only refers to an integer in the numerical interval, it includes the two endpoint integers of the numerical range, and each integer between the two endpoints, which is equivalent to directly listing each integer. When multiple numerical ranges are provided to describe features or characteristics, these numerical ranges can be combined. In other words, unless otherwise specified, the numerical range disclosed in the present application should be understood to include any and all sub-ranges included therein. The "numerical value" in the numerical interval can be any quantitative value, such as a number, a percentage, a ratio, etc. "Numerical interval" allows for a broad range of quantitative intervals such as percentage intervals, ratio intervals, and ratio intervals.

[0051] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which the present invention belongs. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0052] The embodiment of the present application provides a salt recycling device 10 to solve the problem in the prior art that salts such as sodium chloride and sodium sulfate contained in high-salinity wastewater cannot be directly utilized during zero-discharge treatment. The salt recycling device 10 will be described below in conjunction with the accompanying drawings.

[0053] The miscellaneous salt resource device 10 provided in the embodiment of the present application is illustrative, please refer to Figure 1, which is a structural schematic diagram of the miscellaneous salt resource device 10 provided in the embodiment of the present application. The miscellaneous salt resource device 10 of the present application can provide new ideas and methods for solving the industrial application of multi-component miscellaneous salts containing sodium chloride, sodium sulfate, sodium nitrate, etc., and achieve the maximum degree of miscellaneous salt resource utilization with good resource utilization effect. In order to more clearly illustrate the structure of the miscellaneous salt resource device 10, the miscellaneous salt resource device 10 will be introduced in conjunction with the accompanying drawings.

[0054] For example, please refer to FIG. 1 , a salt resource device 10 includes a crushing, screening, dissolving system 100, a hardness, siliconization, and fluorine removal system 200, a primary filter press system 300, an organic matter adsorption system 400, a secondary filter press system 500, a sand filtration system 600, a freezing crystallization system 700, a filtration system, a sodium chloride evaporation crystallization system 1000, and a sodium nitrate cold crystallization system 1100, which are connected in sequence. The crushing, screening, dissolving system 100 is used to break up, crush, and dissolve multi-component salts. The hardness, siliconization, and fluorine removal system 200 removes fluorine, silicon, and hardness from the dissolved solution from the crushing, screening, and dissolving system 100 by adding reagents. The primary filter press system 300 is used to perform the first filter press treatment on the reaction solution from the hardness, siliconization, and fluorine removal system 200. The organic matter adsorption system 400 is used to adsorb the filtrate from the primary filter press system 300 by adding liquid resin and adsorbent to remove part of the organic matter. The secondary filter press system 500 is used to perform the first filter press treatment on the reaction liquid from the organic adsorption system 400. The sand filtration system 600 is used to filter the filtrate from the secondary filter press system 500. The freezing crystallization system 700 is used to freeze and crystallize the filtrate from the sand filtration system 600 to precipitate sodium sulfate. The filtration system is used to filter the frozen clear liquid of the freezing crystallization system 700. The produced water of the filtration system enters the sodium chloride evaporation crystallization system 1000 for evaporation and crystallization to produce sodium chloride. The sodium chloride mother liquor of the sodium chloride evaporation crystallization system 1000 enters the sodium nitrate cold precipitation crystallization system 1100 for cold precipitation and crystallization to obtain sodium nitrate.

[0055] In some embodiments, please refer to FIG. 1 , the filtration system includes an ultrafiltration system 800 and a nanofiltration system 900 which are sequentially distributed along the water flow direction. The ultrafiltration system 800 is used to ultrafilter the frozen clear liquid from the freezing crystallization system 700 to intercept most of the suspended matter and unsettled fine salt. The ultrafiltration water produced by the ultrafiltration system 800 enters the nanofiltration system 900. The nanofiltration system 900 is used to perform nanofiltration treatment on the ultrafiltration water produced by the ultrafiltration system 800. The nanofiltration water containing sodium chloride of the nanofiltration system 900 enters the sodium chloride evaporation crystallization system 1000 for evaporation and crystallization to produce sodium chloride. The nanofiltration system 900 is also connected to the freezing crystallization system 700. The nanofiltration concentrated water of the nanofiltration system 900 flows back to the freezing crystallization system 700. The sodium sulfate contained in the nanofiltration concentrated water of the nanofiltration system 900 returns to the freezing crystallization system 700 for re-freezing and crystallization.

[0056] In the present application, the ultrafiltration system 800 (UF) and the nanofiltration system 900 (NF) are two membrane separation technologies, each of which has unique advantages. When the ultrafiltration system 800 and the nanofiltration system 900 are used in combination, they can provide a more comprehensive treatment effect. Several main advantages of the use of the ultrafiltration system 800 and the nanofiltration system 900 in combination include (1) improving removal efficiency: ultrafiltration can effectively remove most suspended solids, bacteria, viruses, colloids and large molecular organic matter. Nanofiltration can further remove soluble solids, including certain divalent ions, pigments, pesticides, organic pollutants, etc. (2) enhancing system stability: ultrafiltration as a pretreatment can reduce the pollution and blockage of the nanofiltration membrane, extend the service life of the nanofiltration membrane, and reduce operating costs. (3) optimizing energy consumption: by removing large particle impurities through ultrafiltration first, the operating pressure in the subsequent nanofiltration process can be reduced, thereby saving energy. (4) Improve water quality: Combining the treatment capabilities of the two can achieve higher standards of effluent quality and meet more stringent water use requirements, such as drinking water, industrial water or medical water. (5) Flexibility and adaptability: The operating parameters of ultrafiltration and nanofiltration can be adjusted according to changes in the influent water quality to meet different treatment needs. (6) Reduce the use of chemical agents: The efficient physical filtration method reduces the dependence on chemical cleaning, reduces the amount of chemicals used and the treatment cost. (7) Environmental friendliness: Reducing the use of chemical agents means less chemical waste is generated, which is beneficial to environmental protection. (8) Economical: Although the initial investment may be high, in the long run, the economic benefits of the entire system will be better due to the extended life of the membrane and the reduction of operating costs. In summary, in this application, the combination of ultrafiltration system 800 and nanofiltration system 900 can provide a more efficient, more stable and more economical water treatment solution, which is suitable for a variety of industrial and municipal applications.

[0057] In some embodiments, as shown in FIG1 , the impurity salt resource recovery device 10 further includes a mother liquor impurity removal system 1200. The sodium nitrate cold crystallization system 1100 is also connected to the mother liquor impurity removal system 1200. The mother liquor impurity removal system 1200 is also connected to the crushing, screening and dissolution system 100. The mother liquor impurity removal system 1200 is used to remove fine salt with small particle size and some impurities from the sodium nitrate mother liquor from the sodium nitrate cold crystallization system 1100, and to improve the shape of the sodium nitrate mother liquor by adding a mother liquor improver. The sodium nitrate mother liquor treated by the mother liquor impurity removal system 1200 is refluxed to the crushing, screening and dissolution system 100 for circulation.

[0058] In some embodiments, the miscellaneous salt resource recovery device 10 further includes a sodium sulfate hot melt crystallization system 1300. The sodium sulfate hot melt crystallization system 1300 is connected to the freezing crystallization system 700, and the sodium sulfate hot melt crystallization system 1300 is used to remove crystal water from the sodium sulfate from the freezing crystallization system 700 to form sodium sulfate salt.

[0059] In some embodiments, as shown in FIG1 , the miscellaneous salt resource recovery device 10 further includes a sodium sulfate centrifugal drying system 1400. The sodium sulfate centrifugal drying system 1400 is connected to the sodium sulfate hot melt crystallization system 1300, and the sodium sulfate centrifugal drying system 1400 is used to centrifugally dry the sodium sulfate from the sodium sulfate hot melt crystallization system 1300, and control the water content of the sodium sulfate to be no higher than 4%.

[0060] In some embodiments, the impure salt resource recovery device 10 further includes a first fluidized bed. The first fluidized bed is connected to the sodium sulfate centrifugal drying system 1400, and is used for fluidizing and dehydrating the sodium sulfate from the sodium sulfate centrifugal drying system 1400 to control the water content of the sodium sulfate to be no higher than 0.4%.

[0061] In some embodiments, as shown in FIG1 , the miscellaneous salt resource recovery device 10 further includes a sodium chloride centrifugal drying system 1500. The sodium chloride centrifugal drying system 1500 is connected to the sodium chloride evaporation crystallization system 1000, and the sodium chloride centrifugal drying system 1500 is used to centrifugally dry the sodium chloride from the sodium chloride evaporation crystallization system 1000, and control the water content of the sodium chloride to be no higher than 4%.

[0062] In some embodiments, the impure salt resource recovery device 10 further includes a second fluidized bed. The second fluidized bed is connected to the sodium chloride centrifugal drying system 1500, and the second fluidized bed is used for fluidizing and dehydrating the sodium chloride from the sodium chloride centrifugal drying system 1500, and controlling the water content of the sodium chloride to be no higher than 0.4%.

[0063] In some embodiments, as shown in FIG1 , the impurity salt resource recovery device 10 further includes a sodium nitrate centrifugal drying system 1600. The sodium nitrate centrifugal drying system 1600 is connected to the sodium nitrate cold precipitation crystallization system 1100. The sodium nitrate centrifugal drying system 1600 is used to centrifugally dry the sodium nitrate from the sodium nitrate cold precipitation crystallization system 1100, and control the water content of the sodium nitrate to be no higher than 4%.

[0064] In some of the embodiments, the impure salt resource device 10 also includes a third fluidized bed. The third fluidized bed is connected to the sodium nitrate centrifugal drying system 1600, and the third fluidized bed is used to fluidize and dehydrate the sodium nitrate from the sodium nitrate centrifugal drying system 1600, and control the water content of the sodium nitrate to be no more than 0.4%. In the accompanying drawings, the first fluidized bed, the second fluidized bed, and the third fluidized bed are not shown. In the present application, the main features of the first fluidized bed, the second fluidized bed, and the third fluidized bed include: (1) Fluidization: solid particles are suspended under the action of a fluid (usually a gas or a liquid) to form a fluid-like bed. In this state, the friction between the particles is reduced and they can move freely, just like a liquid. (2) Efficient mass transfer and heat transfer: the fluidized bed provides a good contact interface, making the mass transfer and heat transfer between solids, liquids, and gases very efficient. This makes the fluidized bed particularly suitable for processes that require high-efficiency mass transfer and heat transfer, such as drying, heating, cooling, catalytic reactions, etc. (3) Uniform temperature and concentration distribution: Under fluidized conditions, the temperature and reactant concentration distribution inside the bed are relatively uniform, which is conducive to controlling the reaction conditions.

[0065] In some of the embodiments, the moisture content of the filter cake after filtration treatment of the primary filter press system 300 is ≤65%, the filter cloth of the primary filter press system 300 is made of 300-400 mesh polyester material, and the plate and frame water outlet SS of the primary filter press system 300 is ≤20 mg / L.

[0066] In some embodiments, the moisture content of the filter cake after the filter pressing treatment of the secondary filter pressing system 500 is ≤65%, the filter cloth of the secondary filter pressing system 500 is made of 300-400 mesh polyester, and the plate and frame outlet water SS of the secondary filter pressing system 500 is ≤20mg / L. Due to the high density of highly concentrated brine, the precipitated flocs generated during the reaction process are often not easy to settle. The mud and water separation using traditional high-efficiency sedimentation tanks is not effective and often causes mud to turn over on site, resulting in excessive turbidity of the produced water. Therefore, the primary filter pressing system 300 and the secondary filter pressing system 500 of the present application can respectively use plate and frame filter presses to filter the turbid liquid after the reaction to achieve mud and water separation.

[0067] In some of the embodiments, the decolorization rate of the liquid resin added to the organic adsorption system 400 is not less than 95%, and the removal rate of organic matter is not less than 70%; the adsorbent added to the organic adsorption system 400 includes powdered activated carbon, and the powdered activated carbon has a particle size of 0.5mm~2mm and the proportion of activated carbon specifications is more than 85%, the iodine adsorption value of the powdered activated carbon is ≥900mg / g, and the liquid resin added to the organic adsorption system 400 and the adsorption efficiency of the adsorbent organic matter are not less than 90%.

[0068] An embodiment of the present application provides a method for recycling miscellaneous salts.

[0069] In this article, unless otherwise stated, each reaction step may be carried out in the order described herein or may not be carried out in the order described herein. For example, other steps may be included between each reaction step, and the order of the reaction steps may also be appropriately swapped. This can be determined by the technician based on common knowledge and experience. Preferably, the reaction method herein is carried out sequentially.

[0070] A method for recycling miscellaneous salts, using the above-mentioned miscellaneous salt recycling device 10, as shown in FIG1, comprises the following steps:

[0071] Multi-component impure salts enter the crushing, screening and dissolving system for dispersion, crushing and dissolution.

[0072] The reagents are added to the hardness removal, silicon removal and fluorine removal system 200 to remove fluorine, silicon and hardness from the dissolved solution from the crushing, screening and dissolving system 100.

[0073] The primary filter press system 300 is controlled to perform the first filter press treatment on the reaction liquid from the hardness removal, silicon removal and fluorine removal system 200; liquid resin and adsorbent are added to the organic adsorption system 400 to perform adsorption treatment on the filtrate from the primary filter press system 300 to remove part of the organic matter.

[0074] The secondary filter press system 500 is controlled to perform the first filter press treatment on the reaction liquid from the organic matter adsorption system 400; and the sand filtration system 600 is controlled to perform filtering treatment on the filtrate from the secondary filter press system 500.

[0075] The freezing crystallization system 700 is controlled to perform freezing crystallization on the filtrate from the sand filtration system 600 to precipitate sodium sulfate; the filtration system is controlled to filter the frozen clear liquid of the freezing crystallization system 700, and the produced water of the filtration system enters the sodium chloride evaporation crystallization system 1000 for evaporation crystallization to produce sodium chloride, and the sodium chloride mother liquor of the sodium chloride evaporation crystallization system 1000 enters the sodium nitrate cold precipitation crystallization system 1100 for cold precipitation crystallization to obtain sodium nitrate.

[0076] In some embodiments, the method for recycling miscellaneous salts further satisfies at least one of the following conditions:

[0077] In some of the embodiments, a fine crusher is used to break up and crush the multi-component impurities entering the crushing, screening and dissolving system, and the output size after vibration screening is 2mm~4mm.

[0078] In some of the embodiments, the multi-component impure salt enters the crushing, screening and dissolution system for breaking up, crushing and dissolving, and the dissolution concentration is controlled at 25% to 35%.

[0079] In some of the embodiments, when adding reagents to the hardness, siliconization and fluorine removal system 200 to remove fluorine, silicon and hardness from the dissolved solution from the crushing, screening and dissolution system 100, calcium chloride or a defluorinating agent is used for defluorination, and the fluoride index is controlled to be ≤20 mg / L, which can reduce the corrosion rate of the evaporation crystallization system.

[0080] In some of the embodiments, when adding reagents to the hardness removal, silicon removal and fluorine removal system 200 to remove fluorine, silicon and hardness from the dissolved solution from the crushing, screening and dissolution system 100, magnesium oxide or sodium aluminate is used for silicon removal, and the silicon index is controlled to be ≤20 mg / L, which can reduce the fouling of the membrane system and the heat exchanger.

[0081] In some of the embodiments, when adding reagents to the hardness removal, silicon removal and fluorine removal system 200 to remove fluorine, silicon and hardness from the dissolved solution from the crushing, screening and dissolution system 100, sodium carbonate is used for hardness removal to remove the calcium hardness introduced during the addition process and the calcium hardness in the impurities. Controlling the total hardness to ≤100 mg / L can prevent scaling of the nanofiltration membrane and reduce the scaling rate of the evaporation crystallization heat exchanger.

[0082] In some of the embodiments, the freezing crystallization temperature of the freezing crystallization system 700 is controlled to be -5°C~0°C, most of the sulfate ions in the high-concentration brine of the freezing crystallization system 700 are separated and precipitated in the form of sodium sulfate, and the purity of the sodium sulfate obtained by freezing crystallization is not less than 98.5%.

[0083] In some embodiments, the cold crystallization temperature of the sodium nitrate cold crystallization system 1100 is controlled to be 5° C. to 10° C. During the evaporation process of the sodium chloride mother liquor in the sodium chloride evaporation crystallization system 1000, sodium nitrate is continuously enriched. Generally, the solubility of sodium nitrate at 100° C. is 180 g / 100 g water, but the solubility of sodium nitrate at 10° C. is 80 g / 100 g water. Therefore, the cold crystallization temperature of the sodium nitrate cold crystallization system 1100 is controlled to be 5° C. to 10° C. After the sodium chloride mother liquor is cooled to 5° C. to 10° C., most of the sodium nitrate will be cold precipitated, thereby improving the cold crystallization efficiency of the sodium nitrate.

[0084] In some of the embodiments, the sodium nitrate mother liquor of the sodium nitrate cold crystallization system 1100 enters the mother liquor impurity removal system 1200 to remove fine salt with small particle size and some impurities, and a mother liquor improver is added to the mother liquor impurity removal system 1200 to improve the shape of the sodium nitrate mother liquor. The sodium nitrate mother liquor treated by the mother liquor impurity removal system 1200 is returned to the crushing, screening and dissolution system 100 for circulation.

[0085] In some of the embodiments, the concentrated nanofiltration water from the nanofiltration system 900 is returned to the freezing crystallization system 700 for refreezing and crystallization to improve the water treatment efficiency.

[0086] In summary, the above-mentioned miscellaneous salt resource device 10 dissolves the miscellaneous salts and crystallized salts contained in the multi-component miscellaneous salts in water, and captures the organic matter that affects evaporation and crystallization by adding agents, which greatly reduces energy consumption and meets the national energy conservation and consumption reduction initiatives and requirements. The miscellaneous salt resource method of the present application is not limited by the sodium nitrate component in the miscellaneous salts, but also separates the sodium nitrate, which not only solves the problem that nitrate is difficult to remove but also obtains a high-purity sodium nitrate product. Therefore, the present application first puts the dissolved miscellaneous salts into a freezing crystallization device, which can control the sulfate concentration of the frozen clear liquid, and then enters the nanofiltration system 900 to ensure the purity of sodium chloride, and the finally enriched sodium nitrate can be separated into high-purity sodium nitrate by cold analysis, and finally the multi-component miscellaneous salts can be maximized. Resource.

[0087] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0088] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0089] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A device for recycling miscellaneous salts, characterized in that: The invention comprises a crushing, screening and dissolving system, a hardness removal, silicon removal and fluorine removal system, a primary filter press system, an organic matter adsorption system, a secondary filter press system, a sand filtration system, a freezing crystallization system, a filtration system, a sodium chloride evaporation crystallization system and a sodium nitrate cold precipitation crystallization system connected in sequence. The crushing, screening and dissolving system is used to break up, crush and dissolve multi-component impure salts. The hardness removal, silicon removal and fluorine removal system removes fluorine, silicon and hardness from the dissolved solution of the crushing, screening and dissolving system by adding reagents. The primary filter press system is used to perform the first filter press treatment on the reaction solution from the hardness removal, silicon removal and fluorine removal system. The organic matter adsorption system is used to remove the organic matter from the hardness removal, silicon removal and fluorine removal system by adding liquid resin and adsorbent. The filtrate of the primary filter press system is subjected to adsorption treatment to remove part of organic matter, the secondary filter press system is used to perform the first filter press treatment on the reaction liquid from the organic matter adsorption system, the sand filtration system is used to filter the filtrate from the secondary filter press system, the freezing crystallization system is used to perform freezing crystallization on the filtrate from the sand filtration system to precipitate sodium sulfate, the filtration system is used to filter the frozen clear liquid of the freezing crystallization system, the produced water of the filtration system enters the sodium chloride evaporation crystallization system for evaporation crystallization to produce sodium chloride, and the sodium chloride mother liquor of the sodium chloride evaporation crystallization system enters the sodium nitrate cold precipitation crystallization system for cold precipitation crystallization to obtain sodium nitrate.

2. The miscellaneous salt resource recovery device according to claim 1, characterized in that: The filtration system comprises an ultrafiltration system and a nanofiltration system sequentially distributed along the water flow direction, the ultrafiltration system is used to perform ultrafiltration on the frozen clear liquid from the freezing crystallization system to intercept most of the suspended matter and unsettled fine salts, the ultrafiltration water produced by the ultrafiltration system enters the nanofiltration system, the nanofiltration system is used to perform nanofiltration treatment on the ultrafiltration water produced by the ultrafiltration system, and the nanofiltration water containing sodium chloride from the nanofiltration system enters the sodium chloride evaporation crystallization system for evaporation and crystallization to produce sodium chloride; The nanofiltration system is also connected to the freezing crystallization system, and the nanofiltration concentrate of the nanofiltration system flows back to the freezing crystallization system, and the sodium sulfate contained in the nanofiltration concentrate of the nanofiltration system is returned to the freezing crystallization system for re-freezing crystallization.

3. The miscellaneous salt resource recovery device according to claim 1, characterized in that: The impurity salt resource recovery device also includes a mother liquor impurity removal system, the sodium nitrate cold precipitation crystallization system is also connected to the mother liquor impurity removal system, and the mother liquor impurity removal system is also connected to the crushing, screening and dissolution system; The mother liquor impurity removal system is used to remove fine salt with small particle size and some impurities from the sodium nitrate mother liquor from the sodium nitrate cold precipitation crystallization system, and to improve the shape of the sodium nitrate mother liquor by adding a mother liquor improver. The sodium nitrate mother liquor treated by the mother liquor impurity removal system is refluxed to the crushing, screening and dissolution system for circulation.

4. The miscellaneous salt resource recovery device according to any one of claims 1 to 3, characterized in that: The miscellaneous salt resource recovery device also includes a sodium sulfate hot-melt crystallization system, which is connected to the frozen crystallization system and is used to remove crystal water from the sodium sulfate from the frozen crystallization system to form sodium sulfate salt.

5. The miscellaneous salt resource recovery device according to claim 4, characterized in that: The miscellaneous salt resource utilization device also includes a sodium sulfate centrifugal drying system, which is connected to the sodium sulfate hot-melt crystallization system. The sodium sulfate centrifugal drying system is used to centrifugally dry the sodium sulfate from the sodium sulfate hot-melt crystallization system to control the water content of the sodium sulfate to be no higher than 4%.

6. The miscellaneous salt resource recovery device according to any one of claims 1 to 3 and 5, characterized in that: The miscellaneous salt resource utilization device also includes a sodium chloride centrifugal drying system, which is connected to the sodium chloride evaporation and crystallization system. The sodium chloride centrifugal drying system is used to centrifugally dry the sodium chloride from the sodium chloride evaporation and crystallization system to control the water content of the sodium chloride to be no higher than 4%.

7. The miscellaneous salt resource recovery device according to any one of claims 1 to 3 and 5, characterized in that: The miscellaneous salt resource utilization device also includes a sodium nitrate centrifugal drying system, which is connected to the sodium nitrate cold precipitation crystallization system. The sodium nitrate centrifugal drying system is used to centrifugally dry the sodium nitrate from the sodium nitrate cold precipitation crystallization system to control the water content of the sodium nitrate to be no higher than 4%.

8. The miscellaneous salt resource recovery device according to any one of claims 1 to 3 and 5, characterized in that: The mixed salt resource recovery device meets at least one of the following conditions: (1) The moisture content of the filter cake after the filtration treatment of the first-stage filter press system is ≤65%, the filter cloth of the first-stage filter press system is made of 300-400 mesh polyester, and the plate and frame outlet water SS of the first-stage filter press system is ≤20 mg / L; (2) The moisture content of the filter cake after the filtration treatment of the secondary filter press system is ≤65%, the filter cloth of the secondary filter press system is made of 300-400 mesh polyester, and the plate and frame outlet water SS of the secondary filter press system is ≤20 mg / L; (3) The decolorization rate of the liquid resin added to the organic adsorption system is not less than 95%, and the removal rate of organic matter is not less than 70%; the adsorbent added to the organic adsorption system includes powdered activated carbon, and the powdered activated carbon has a particle size of 0.5mm~2mm and accounts for more than 85% of the specifications. The iodine adsorption value of the powdered activated carbon is ≥900mg / g. The adsorption efficiency of the liquid resin added to the organic adsorption system and the adsorbent for organic matter is not less than 90%.

9. A method for recycling miscellaneous salts, characterized in that: The use of the miscellaneous salt resource recovery device according to any one of claims 1 to 8 comprises the following steps: Multi-component salts enter the crushing, screening and dissolving system for breaking up, crushing and dissolving; Adding reagents to the hardness removal, silicon removal and fluorine removal system to remove fluorine, silicon and hardness from the dissolved solution from the crushing, screening and dissolving system; Controlling the primary filter press system to perform a first filter press treatment on the reaction liquid from the hardness removal, silicon removal and fluorine removal system; adding liquid resin and adsorbent to the organic matter adsorption system to perform adsorption treatment on the filtrate from the primary filter press system to remove part of the organic matter; Controlling the secondary filter press system to perform a first filter press treatment on the reaction liquid from the organic matter adsorption system; controlling the sand filtration system to perform filtering treatment on the filtrate from the secondary filter press system; The freezing crystallization system is controlled to perform freezing crystallization on the filtrate from the sand filtration system to precipitate sodium sulfate; the filtration system is controlled to filter the frozen clear liquid of the freezing crystallization system, the produced water of the filtration system enters the sodium chloride evaporation crystallization system for evaporation crystallization to produce sodium chloride, and the sodium chloride mother liquor of the sodium chloride evaporation crystallization system enters the sodium nitrate cold precipitation crystallization system for cold precipitation crystallization to obtain sodium nitrate.

10. The method for recycling miscellaneous salts according to claim 9, characterized in that: The method for recycling miscellaneous salts also satisfies at least one of the following conditions: (1) Use a fine crusher to break up and crush the multi-component impure salts that enter the crushing, screening and dissolving system. After vibration screening, the output size is 2mm~4mm; (2) The multi-component impure salts enter the crushing, screening and dissolution system for breaking up, crushing and dissolving, and the dissolution concentration is controlled at 25%~35%; (3) When adding reagents to the hardness removal, silicon removal and fluorine removal system to remove fluorine, silicon and hardness from the dissolved solution of the crushing, screening and dissolving system, calcium chloride or a defluorinating agent is used to remove fluorine and control the fluoride index to ≤20mg / L; (4) When adding reagents to the hardness removal, silicon removal and fluorine removal system to remove fluorine, silicon and hardness from the dissolving solution from the crushing, screening and dissolving system, magnesium oxide or sodium aluminate is used for silicon removal, and the silicon index is controlled to be ≤20mg / L; (5) When adding reagents to the hardness removal, silicon removal and fluorine removal system to remove fluorine, silicon and hardness from the dissolved solution from the crushing, screening and dissolving system, sodium carbonate is used for hardness removal to remove the calcium hardness introduced during the addition of reagents and the calcium hardness in the impurities, and the total hardness is controlled to be ≤100 mg / L; (6) The freezing crystallization temperature of the freezing crystallization system is controlled to be -5°C to 0°C, most of the sulfate ions in the high-concentration brine of the freezing crystallization system are separated and precipitated in the form of sodium sulfate, and the purity of the sodium sulfate obtained by freezing crystallization is not less than 98.5%; (7) Controlling the cold crystallization temperature of the sodium nitrate cold crystallization system to be 5°C to 10°C.

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