Waste salt recycling system

Abstract

This utility model belongs to the field of waste salt resource utilization technology, specifically relating to a waste salt recycling system. The system includes: a pyrolysis unit, a purification unit, a salt separation unit, and a crystallization unit connected in sequence, as well as a sludge treatment unit connected to the purification unit. The pyrolysis unit includes pyrolysis equipment; the purification unit includes a dissolving tank, a reaction tank, a tubular ultrafiltration device, a pH adjustment tank, an ion exchange device, and a decarbonization device connected in sequence; the salt separation unit includes a nanofiltration device; the crystallization unit includes an MVR evaporation device; and the sludge treatment unit includes a sludge tank and a filter press. The dissolving tank is connected to both the pyrolysis equipment and the sludge tank; the decarbonization device is connected to the nanofiltration device; and the nanofiltration device is connected to the MVR evaporation device. This system achieves harmless utilization and produces sodium chloride through pyrolysis, purification, salt separation, and crystallization, effectively realizing the recycling and reuse of industrial waste salt.

Description

Technical Field

[0001] This utility model belongs to the field of waste salt resource utilization technology, and in particular relates to a waste salt recycling system. Background Technology

[0002] With the development of my country's industry, the output of industrial hazardous waste has been increasing year by year. 25% of industrial hazardous waste is waste salt. Industrial waste salt mainly comes from the salt-producing stages of industrial production processes, including reaction salts from mother liquor, neutralizing salts from acid-base chemical reactions, salting-out salts, salt mud from distillation residues, and waste salt produced after the concentration treatment of high-salt wastewater. Waste salt is divided into two main categories: sodium chloride and sodium sulfate, primarily originating from industries such as pesticides, pharmaceuticals, fine chemicals, and printing and dyeing. The composition of industrial waste salt is complex, often consisting of by-product salts containing various organic substances or heavy metals. Improper treatment can directly lead to the pollution of surface water, groundwater, and soil.

[0003] Currently, the main methods for disposing of hazardous salt waste are incineration and landfill. However, landfilling waste salt lacks "recyclability" and "cleanliness," not only occupying large amounts of land resources and making large-scale construction difficult, but also failing to fundamentally solve the waste salt disposal problem. Direct incineration, on the other hand, easily causes incineration equipment to accumulate on the walls, become clogged, and shorten equipment lifespan. In addition, landfilling and incineration cannot reuse the salt in waste salt, resulting in resource waste.

[0004] Therefore, how to solve the problems of damage to incineration equipment and environmental pollution caused by landfill due to the complex composition of industrial waste salt, while avoiding the waste of salt resources, is a technical problem that urgently needs to be solved by those skilled in the art.

[0005] It should be noted that the information disclosed in this background section is only for understanding the background technology of this application concept, and therefore, the above description is not considered to constitute prior art information. Utility Model Content

[0006] This disclosure provides at least one waste salt recycling system.

[0007] In a first aspect, embodiments of this disclosure provide a waste salt recycling system, comprising:

[0008] The pyrolysis unit, impurity removal unit, salt separation unit, crystallization unit, and sludge treatment unit connected in sequence are connected to the impurity removal unit in sequence.

[0009] The pyrolysis unit includes pyrolysis equipment;

[0010] The impurity removal unit includes a dissolution tank, a reaction tank, a tubular ultrafiltration device, a pH adjustment tank, an ion exchange device, and a decarbonization device connected in sequence.

[0011] The salt separation unit includes a nanofiltration device;

[0012] The crystallization unit includes an MVR evaporation device;

[0013] The sludge treatment unit includes a sludge tank and a filter press;

[0014] The dissolving tank is connected to the pyrolysis equipment and the sludge tank, respectively; the decarbonization equipment is connected to the nanofiltration equipment; and the nanofiltration equipment is connected to the MVR evaporation equipment.

[0015] In one alternative implementation, the pyrolysis equipment is a rotary pyrolysis furnace.

[0016] In one alternative embodiment, the tubular ultrafiltration device includes a cross-flow tubular membrane module with its inlet connected to the outlet of the reaction tank and its outlet connected to a pH adjustment tank.

[0017] In one optional embodiment, the ion exchange device includes a column filled with ion exchange resin, with its inlet end connected to the outlet of a pH adjustment tank and its outlet end connected to the inlet of a decarbonization device.

[0018] In one optional embodiment, the decarbonization equipment includes a decarbonization tower and a vacuum pump, wherein the liquid inlet of the decarbonization tower is connected to the outlet of an ion exchange device, the gas outlet is connected to the vacuum pump, and the liquid outlet is connected to a nanofiltration device.

[0019] In one alternative embodiment, the MVR evaporation apparatus includes an evaporator crystallizer;

[0020] The feed inlet of the evaporator crystallizer is connected to the concentrate outlet of the nanofiltration equipment;

[0021] The bottom of the evaporator crystallizer is provided with a crystal slurry outlet.

[0022] In one alternative embodiment, the tubular ultrafiltration device is further provided with a concentrate pipeline, which is connected to a dissolution tank.

[0023] In one alternative embodiment, the filter press is provided with a filtrate pipeline that is connected to a dissolving tank.

[0024] In one optional embodiment, the reaction tank is provided with inlets for adding Na2CO3, NaOH, and magnesium.

[0025] The pH adjusting tank is equipped with an H2SO4 dosing port.

[0026] In one optional embodiment, the nanofiltration device includes a primary nanofiltration membrane and a secondary nanofiltration membrane connected in series, wherein the concentrate outlet of the primary nanofiltration membrane is connected to the inlet of the secondary nanofiltration membrane, and the concentrate outlet of the secondary nanofiltration membrane is connected to the feed inlet of the MVR evaporator.

[0027] The beneficial effects of this utility model are that, through steps such as pyrolysis, impurity removal, salt separation, and crystallization, this waste salt recycling system can effectively decompose organic matter and heavy metal ions in waste salt, and extract sodium chloride from the waste salt, thereby realizing the recycling of waste salt.

[0028] Other features and advantages of this invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objectives and other advantages of this invention are realized and obtained through the structures particularly pointed out in the description and drawings.

[0029] To make the above-mentioned objectives, features and advantages of this utility model more apparent and understandable, preferred embodiments are described in detail below with reference to the accompanying drawings. Attached Figure Description

[0030] To more clearly illustrate the specific embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0031] Figure 1 This is a diagram of a waste salt recycling system provided in an embodiment of the present disclosure.

[0032] In the picture:

[0033] 100. Pyrolysis unit; 200. Impurity removal unit; 210. Concentrate pipeline; 300. Salt separation unit; 400. Crystallization unit; 500. Sludge treatment unit; 510. Filtrate pipeline. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0035] In this document, when it is mentioned that a first component is located on a second component, this can mean that the first component can be directly formed on the second component, or that a third component can be inserted between the first and second components. Furthermore, in the accompanying drawings, the thickness of components may be exaggerated or reduced for the purpose of effectively describing the technical content.

[0036] In this document, when an element or layer is referred to as “located,” “joined to,” “connected to,” “attached to,” or “coupled to” another element or layer, it may be directly located, joined, connected, attached to, or coupled to the other element or layer, or there may be intermediate elements or layers present. Conversely, when an element is referred to as “directly on another element or layer,” “directly joined to,” “directly connected to,” “directly attached to,” or “directly coupled to” another element or layer, there may be no intermediate elements or layers present. Other terms used to describe relationships between elements should be interpreted in a similar manner (e.g., “between” versus “directly between,” “adjacent” versus “directly adjacent,” etc.). As used herein, the term “and / or” includes any and all combinations of one or more of the related listed items.

[0037] In this document, exemplary embodiments of the present disclosure will be described in more detail with reference to the accompanying drawings. As used herein, expressions such as “at least one of…” modify the entire list of elements when following a list of elements, rather than individual elements in the list. For example, the expression “at least one of a, b, and c” should be understood to include only a, only b, only c, both a and b, both a and c, both b and c, or all of a, b, and c.

[0038] The terminology used herein is for the purpose of describing specific exemplary configurations only and is not intended to be limiting. As used herein, the singular articles “a,” “an,” and “the” may also be intended to include plural forms unless otherwise clearly stated herein. The terms “comprising,” “including,” and “having” are inclusive and thus specify the presence of features, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and / or combinations thereof. The method steps, processes, and operations described herein should not be construed as requiring them to be performed in the specific order discussed or shown, unless specifically identified as such. Additional or alternative steps may be employed.

[0039] As used herein, the phrases “in one embodiment,” “according to one embodiment,” “in some embodiments,” etc., generally refer to the fact that a particular feature, structure, or characteristic following the phrase can be included in at least one embodiment of this disclosure. Therefore, a particular feature, structure, or characteristic can be included in more than one embodiment of this disclosure, such that these phrases do not necessarily refer to the same embodiment. As used herein, the terms “example,” “exemplary,” etc., are used to “serve as an example, instance, or illustration.” Any implementation, aspect, or design described herein as “example” or “exemplary” is not necessarily to be construed as preferred or superior to other implementations, aspects, or designs. Rather, the use of the terms “example,” “exemplary,” etc., is intended to present concepts in a specific manner.

[0040] Research has revealed the shortcomings of existing technologies: Currently, the main methods for disposing of hazardous salt waste are incineration and landfill. However, landfilling waste salt lacks "recyclability" and "cleanliness," not only consuming large amounts of land resources and hindering large-scale construction, but also failing to fundamentally solve the waste salt disposal problem. Direct incineration, on the other hand, easily causes wall clogging and blockage of incineration equipment, reducing its lifespan. Neither landfilling nor direct incineration can recover and utilize the salt content in the waste salt, resulting in resource waste.

[0041] Based on the above research, this disclosure provides a waste salt recycling system that can effectively decompose organic matter and heavy metal ions in waste salt and extract sodium chloride from the waste salt, thereby realizing the recycling of waste salt.

[0042] The shortcomings of the above solutions are the result of the inventor's practical experience and careful research. Therefore, the discovery process of the above problems and the solutions proposed in this disclosure should be considered as the inventor's contribution to this disclosure.

[0043] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0044] The following detailed description, with reference to the accompanying drawings, describes some embodiments of the present invention. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0045] See Figure 1 This disclosure provides a waste salt recycling system, comprising: a pyrolysis unit 100, a purification unit 200, a salt separation unit 300, and a crystallization unit 400 connected in sequence, and a sludge treatment unit 500 connected to the purification unit 200. The pyrolysis unit 100 includes pyrolysis equipment for decomposing organic matter in the waste salt. The purification unit 200 includes a dissolving tank, a reaction tank, a tubular ultrafiltration device, a pH adjustment tank, an ion exchange device, and a decarbonization device connected in sequence. The salt separation unit 300 includes a nanofiltration device; the crystallization unit 400 includes an MVR evaporator; and the sludge treatment unit 500 includes a sludge tank and a filter press. The dissolving tank is connected to both the pyrolysis equipment and the sludge tank; the decarbonization device is connected to the nanofiltration device; and the nanofiltration device is connected to the MVR evaporator.

[0046] See also Figure 1 In some embodiments, the pyrolysis equipment is a rotary pyrolysis furnace.

[0047] See also Figure 1 In some embodiments, the tubular ultrafiltration device includes a cross-flow tubular membrane module with its inlet connected to the outlet of the reaction tank and its outlet connected to a pH adjustment tank.

[0048] See also Figure 1 In some embodiments, the ion exchange device includes a column filled with ion exchange resin, with its inlet end connected to the outlet of a pH adjustment tank and its outlet end connected to the inlet of a decarbonation device.

[0049] See also Figure 1 In some embodiments, the decarbonization equipment includes a decarbonization tower and a vacuum pump. The liquid inlet of the decarbonization tower is connected to the outlet of the ion exchange equipment, the gas outlet is connected to the vacuum pump, and the liquid outlet is connected to the nanofiltration equipment.

[0050] See also Figure 1 In some embodiments, the MVR evaporation equipment includes an evaporator crystallizer; the feed inlet of the evaporator crystallizer is connected to the concentrate outlet of the nanofiltration equipment; and a crystal slurry outlet is provided at the bottom of the evaporator crystallizer.

[0051] See also Figure 1 In some embodiments, the tubular ultrafiltration device is also provided with a concentrate pipe 210, which is connected to the dissolution tank.

[0052] See also Figure 1 In some embodiments, the filter press is provided with a filtrate pipe 510, which is connected to a dissolving tank.

[0053] See also Figure 1 In some embodiments, the reaction tank is equipped with inlets for adding Na2CO3, NaOH and magnesium; the pH adjustment tank is equipped with an inlet for adding H2SO4.

[0054] See also Figure 1 In some embodiments, the nanofiltration device includes a primary nanofiltration membrane and a secondary nanofiltration membrane connected in series, with the concentrate outlet of the primary nanofiltration membrane connected to the inlet of the secondary nanofiltration membrane, and the concentrate outlet of the secondary nanofiltration membrane connected to the feed inlet of the MVR evaporator.

[0055] See Figure 1 The process of utilizing the above-mentioned waste salt recycling system includes the following steps:

[0056] Waste salt is fed into a rotary pyrolysis furnace, where the organic matter in the waste salt undergoes incomplete oxidation under oxygen-deficient conditions of 600℃~700℃, decomposing into CH4, H2, CO and coke, and obtaining waste salt residue.

[0057] Furthermore, the waste salt residue after pyrolysis is dissolved in a dissolving tank and then fed into a reaction tank. Magnesium agent, sodium hydroxide, and sodium carbonate are added to the reaction tank to remove silicates, calcium and magnesium ions, and heavy metal ions. The solution is then fed into a tubular ultrafiltration device. The concentrated water from ultrafiltration is returned to the dissolving tank through the concentrated water pipe 210. After sedimentation, it is periodically discharged to the sludge tank for sludge dewatering treatment.

[0058] Furthermore, the filtered salt solution is fed into a pH adjustment tank, and sulfuric acid is added to adjust the pH of the solution to 4.5-5.5, creating acidic conditions for subsequent ion exchange;

[0059] Furthermore, the pH-adjusted salt solution is fed into the ion exchange equipment, where the ion exchange resin deeply adsorbs trace heavy metals and residual calcium and magnesium ions, thereby improving the purity of the salt solution.

[0060] Furthermore, CO2 is efficiently removed in an acidic environment using a decarbonization tower and vacuum pump, eliminating the risk of crystallization and foaming, and improving salt purity.

[0061] Furthermore, the salt solution is fed into the nanofiltration device. The primary nanofiltration membrane in the device can retain residual large molecular organic matter, while the secondary nanofiltration membrane separates the primary concentrate, achieving efficient separation of NaCl and Na2SO4.

[0062] Furthermore, the salt solution filtered by the nanofiltration equipment enters the MVR evaporation equipment, where it is evaporated and crystallized to obtain high-purity sodium chloride;

[0063] Furthermore, the sludge in the sludge tank is separated into solid and liquid by a filter press, and the liquid is fed into a dissolving tank through the filtrate pipe 510 to recover the residual salt.

[0064] In summary, this waste salt recycling system can effectively decompose organic matter and heavy metal ions in waste salt through steps such as pyrolysis, impurity removal, salt separation, and crystallization, and extract sodium chloride from the waste salt, thus realizing the recycling of waste salt.

[0065] In the description of the embodiments of this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0066] In the description of this utility model, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. Furthermore, terms such as "first," "second," and other numerical terms used herein do not imply order or sequence unless expressly indicated herein. Therefore, without departing from the teachings of the exemplary embodiments, the first element, component, region, layer, or segment discussed above may be referred to as the second element, component, region, layer, or segment.

[0067] Spatially relative terms, such as “inside,” “outside,” “below,” “below,” “down,” “above,” “up,” etc., may be used herein to describe the relationship between one element or feature illustrated in the figures and another element or feature. In addition to the orientations depicted in the figures, spatially relative terms may be intended to cover different orientations of the device in use or operation. For example, if the device in the figure is flipped, an element described as “below” or “below” other elements or features would be oriented as “above” other elements or features. Thus, the example term “below” can cover both above and below orientations. The device may be oriented in other ways (rotated 90 degrees or in other orientations), and the spatially relative descriptors used herein are interpreted accordingly.

[0068] In the above discussion, unless otherwise stated, when used to describe numerical values, the terms “about,” “approximately,” “basically,” etc., indicate a change of + / - 10% in that value.

[0069] Based on the above-described preferred embodiments of this utility model, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the technical concept of this utility model. The technical scope of this utility model is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A waste salt recycling system, characterized in that, include: The pyrolysis unit (100), the impurity removal unit (200), the salt separation unit (300), the crystallization unit (400), and the sludge treatment unit (500) connected in sequence to the impurity removal unit (200); The pyrolysis unit (100) includes pyrolysis equipment; The impurity removal unit (200) includes a dissolution tank, a reaction tank, a tubular ultrafiltration device, a pH adjustment tank, an ion exchange device, and a decarbonization device connected in sequence. The salt separation unit (300) includes a nanofiltration device; The crystallization unit (400) includes an MVR evaporation device; The sludge treatment unit (500) includes a sludge tank and a filter press; The dissolving tank is connected to the pyrolysis equipment and the sludge tank, respectively; the decarbonization equipment is connected to the nanofiltration equipment; and the nanofiltration equipment is connected to the MVR evaporation equipment.

2. The waste salt recycling system as described in claim 1, characterized in that, The pyrolysis equipment is a rotary pyrolysis furnace.

3. The waste salt recycling system as described in claim 1, characterized in that, The tubular ultrafiltration equipment includes a cross-flow tubular membrane module, with its inlet connected to the outlet of the reaction tank and its outlet connected to a pH adjustment tank.

4. The waste salt recycling system as described in claim 1, characterized in that, The ion exchange equipment includes a column filled with ion exchange resin, with its inlet end connected to the outlet of a pH adjustment tank and its outlet end connected to the inlet of a decarbonization device.

5. The waste salt recycling system as described in claim 1, characterized in that, The decarbonization equipment includes a decarbonization tower and a vacuum pump. The liquid inlet of the decarbonization tower is connected to the outlet of the ion exchange equipment, the gas outlet is connected to the vacuum pump, and the liquid outlet is connected to the nanofiltration equipment.

6. The waste salt recycling system as described in claim 1, characterized in that, The MVR evaporation equipment includes an evaporator crystallizer; The feed inlet of the evaporator crystallizer is connected to the concentrate outlet of the nanofiltration equipment; The bottom of the evaporator crystallizer is provided with a crystal slurry outlet.

7. The waste salt recycling system as described in claim 1, characterized in that, The tubular ultrafiltration equipment is also equipped with a concentrate pipeline (210), which is connected to the dissolution tank.

8. The waste salt recycling system as described in claim 1, characterized in that, The filter press is equipped with a filtrate pipe (510), which is connected to the dissolving tank.

9. The waste salt recycling system as described in claim 1, characterized in that, The reaction tank is equipped with inlets for adding Na2CO3, NaOH, and magnesium. The pH adjusting tank is equipped with an H2SO4 dosing port.

10. The waste salt recycling system as described in claim 1, characterized in that, The nanofiltration device includes a primary nanofiltration membrane and a secondary nanofiltration membrane connected in series. The concentrate outlet of the primary nanofiltration membrane is connected to the inlet of the secondary nanofiltration membrane, and the concentrate outlet of the secondary nanofiltration membrane is connected to the feed inlet of the MVR evaporator.

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