阅读说明：本技术 一种工业废盐资源化处理方法和设备 (Method and equipment for recycling industrial waste salt ) 是由 陈福泰 褚永前 杨艳 白立强 于 2019-12-02 设计创作，主要内容包括：本发明提供的工业废盐资源化处理方法和设备,该方法包括如下步骤：工业废盐依次经溶解、化学预除杂、深度除杂、有机物浓缩减量、吸附氧化脱色和多效蒸发结晶分别得到硫酸钠、氯化钠和硝酸钠晶体；所述硫酸钠结晶温度为75-85℃；氯化钠结晶温度为60-70℃；硝酸钠结晶温度为45-55℃。本发明提供的工业废盐资源化处理方法,通过采用上述步骤首先除去工业废盐中的有机物及其他杂质,然后通过蒸发过程的温度控制来实现分盐结晶,利用氯化钠、硝酸钠和硫酸钠三相共饱和点在不同温度下的差异以及各盐的溶解度,进行分盐结晶,分盐结晶得到的氯化钠、硝酸钠和硫酸钠的纯度和白度均达到工业级标准,可直接应用。(The invention provides a method and a device for recycling industrial waste salt, wherein the method comprises the following steps: sequentially dissolving industrial waste salt, chemically pre-removing impurities, deeply removing impurities, concentrating and reducing organic matters, carrying out adsorption oxidation and decolorization, and carrying out multi-effect evaporation and crystallization to respectively obtain sodium sulfate, sodium chloride and sodium nitrate crystals; the crystallization temperature of the sodium sulfate is 75-85 ℃; the crystallization temperature of the sodium chloride is 60-70 ℃; the crystallization temperature of the sodium nitrate is 45-55 ℃. According to the method for recycling the industrial waste salt, organic matters and other impurities in the industrial waste salt are removed firstly through the steps, then salt separation crystallization is realized through temperature control in the evaporation process, salt separation crystallization is performed by utilizing the difference of three-phase common saturation points of sodium chloride, sodium nitrate and sodium sulfate at different temperatures and the solubility of each salt, and the purity and whiteness of the sodium chloride, sodium nitrate and sodium sulfate obtained through the salt separation crystallization all reach industrial grade standards and can be directly applied.)

1. A resource treatment method for industrial waste salt is characterized by comprising the following steps:

sequentially dissolving industrial waste salt, chemically pre-removing impurities, deeply removing impurities, concentrating and reducing organic matters, carrying out adsorption oxidation and decolorization, and carrying out multi-effect evaporation and crystallization to respectively obtain sodium sulfate, sodium chloride and sodium nitrate crystals;

wherein the crystallization temperature of the sodium sulfate is 75-85 ℃; the crystallization temperature of the sodium chloride is 60-70 ℃; the crystallization temperature of sodium nitrate is 45-55 ℃.

2. The method for recycling industrial waste salt as claimed in claim 1, wherein the multi-effect evaporation crystallization is to obtain sodium sulfate, sodium chloride and sodium nitrate by performing three-time crystallization on mother liquor obtained by sequentially performing one-effect, two-effect, three-effect and four-effect evaporation on a salt solution subjected to adsorption, oxidation and decoloration.

3. The method for recycling industrial waste salt according to claim 1 or 2, wherein the dissolving is to remove insoluble substances after the industrial waste salt is fully dissolved by stirring, so as to obtain a first-grade clear salt solution.

4. The method as claimed in claim 3, wherein the chemical pre-purification is performed by precipitating the first-stage clarified salt solution to obtain a second-stage clarified salt solution; preferably, the number of the precipitation treatments is not less than 2.

5. The method as claimed in claim 4, wherein the deep impurity removal is performed by sequentially subjecting the secondary clarified salt solution to microfiltration membrane, resin adsorption and degassing to obtain a degassed salt solution.

6. The method for recycling industrial waste salt according to claim 5, wherein said resin is a chelate resin and is periodically regenerated;

preferably, the degassing treatment is to adjust the pH of the salt solution after the resin treatment so that the volatile weak acid radical ions are converted into gas, and then the gas is removed by blowing to obtain a degassed salt solution.

7. The method as claimed in claim 3, wherein the concentration and decrement of organic substances means that the degassed salt solution is passed through a separation membrane to retain organic substances, thereby obtaining a purified salt solution and a concentrated solution.

8. The method for recycling industrial waste salt according to claim 3, wherein the adsorption, oxidation and decoloration are carried out by adsorbing the purified salt solution with a stacking filler, and then fully mixing the purified salt solution with an oxidant for reaction to remove chromophoric groups and a part of organic matters;

preferably, the stacked filler is at least one of fiber balls, activated carbon and polypropylene soft filler; the oxidant is at least one of ozone, Fenton reagent and hydrogen peroxide.

9. The method as claimed in claim 7, wherein the condensate water generated during the multi-effect evaporation and crystallization is used for washing the concentrate, and the washed condensate water is recycled to the dissolution step for dissolving the industrial salt.

10. An apparatus suitable for the industrial waste salt recycling method according to any one of claims 1 to 9, characterized in that: the device comprises a dissolving tank, a chemical pre-impurity removal system, a deep impurity removal system, an organic matter concentration and reduction system, an adsorption oxidation system and an evaporative crystallization system which are connected in sequence;

the chemical pre-impurity-removing system comprises a primary reactor, a primary clarifier, a secondary reactor, a secondary clarifier and a matched dosing device;

the deep impurity removal system comprises a microfiltration device, a resin adsorption device and a degassing device;

the organic matter concentration and reduction system is a membrane separation device;

the adsorption oxidation system comprises a filler adsorption device and an oxidation device;

the evaporative crystallization system is a multi-effect evaporative crystallization device.

Technical Field

The invention relates to the technical field of industrial waste salt treatment, in particular to a method and equipment for recycling industrial waste salt.

Background

The waste salt mainly refers to byproduct crystalline salt generated in industrial production, and is mainly divided into single waste salt, mixed salt and miscellaneous salt (containing impurities) according to the composition; the waste salt is mainly derived from chemical production and wastewater treatment, and comprises waste salt generated in the processes of pure water preparation, softening, high-salinity wastewater and the like, and waste salt generated in the processes of byproduct synthesis and the like in the production of pesticides and chlor-alkali industries. Because the waste salt contains a large amount of toxic and harmful substances, such as organic pollutants, heavy metal elements and the like, if the waste salt is stacked unreasonably, soil, underground water and air are easily polluted. In the face of increasingly strict environmental protection policies, the treatment of waste salt, residues and distillation residual liquid generated in the chemical industry becomes a problem to be solved urgently.

At present, resource disposal and landfill treatment are commonly used in the disposal method of the waste salt. The direct landfill of the waste salt is easier to absorb water than other common industrial wastes, and if the waste salt is scattered and filled, the problem of sedimentation of the pile is easy to occur in the later period of the pile, so that potential safety hazards are brought to the subsequent landfill operation. The existing soluble hazardous wastes such as waste salt and the like are directly buried after being cured and cured by cement, and for a flexible landfill, the waste salt has strong solubility, high leakage possibility and great risk, and has great potential safety hazard to the environment in the area.

In the aspect of resource treatment of waste salt, methods commonly used for treating waste salt containing organic matters at present include methods such as secondary concentration and crystallization treatment after dissolution and refining, a direct thermal incineration method, high-temperature carbonization and the like, but the methods have low removal rate of the organic matters in the waste salt, and for single waste salt, solid salt contains impurities such as heavy metals, organic matters and the like; for mixed salt, the solid salt not only contains organic matters and heavy metals, but also contains sodium chloride, sodium nitrate and sodium sulfate, which can limit the use of the salt, and only can be used as a snow melting agent or a weaving dye agent in a small amount; most of the residual salt can be only buried or dumped, which not only easily causes pollution to the environment, but also causes great waste of resources.

Therefore, in order to solve the above problems, researchers have improved the recycling of waste salt, for example, Chinese patent document CN14909494A discloses a process for purifying industrial high-concentration brine, which comprises the following steps of (1) carrying out precipitation reaction treatment on industrial high-concentration brine to remove PO in wastewater₄ ^3-、C0₃ ^2-SS, C0D, fluorine, total silicon, calcium, iron, barium and strontium ions to obtain clear effluent; (2) carrying out ion exchange treatment on the clear effluent obtained in the step (1), and further removing calcium, magnesium, barium and strontium metal ions in the wastewater to obtain ion exchange effluent; (3) degassing the ion exchange effluent obtained in the step (2), converting carbonate and bicarbonate radicals in the wastewater into carbon dioxide, and removing by blowing to obtain degassed effluent; (4) performing decoloring treatment on the degassed effluent obtained in the step (3), and concentrating to separate organic coloring matters to obtain decolored effluent; (5) and (4) carrying out oxidation treatment on the decolored effluent obtained in the step (4), oxidizing to remove organic matters, and preparing salt from the final produced water through multi-effect evaporation crystallization. Although the process reduces the environmental pollution, the waste of resources, the hazards of scaling and corrosion in the equipment in the multi-effect evaporation and crystallization process and the like, only mixed salt which is a mixture of sodium chloride, sodium nitrate and sodium sulfate is finally obtained by the process, and the standard of industrial salt is not met, so that the application of the mixed salt is still limited, namely the waste salt subjected to resource treatment cannot be effectively utilized.

Disclosure of Invention

Therefore, the technical problem to be solved by the invention is to overcome the defect that the industrial waste salt cannot be effectively utilized after being subjected to resource treatment in the prior art, so that the method and the equipment for resource treatment of the industrial waste salt are provided.

Therefore, the invention provides the following technical scheme:

a method for recycling industrial waste salt comprises the following steps:

sequentially dissolving industrial waste salt, chemically pre-removing impurities, deeply removing impurities, concentrating and reducing organic matters, carrying out adsorption oxidation and decolorization, and carrying out multi-effect evaporation and crystallization to respectively obtain sodium sulfate, sodium chloride and sodium nitrate crystals;

wherein the crystallization temperature of the sodium sulfate is 75-85 ℃; the crystallization temperature of the sodium chloride is 60-70 ℃; the crystallization temperature of sodium nitrate is 45-55 ℃.

The multi-effect evaporative crystallization is to obtain sodium sulfate, sodium chloride and sodium nitrate by carrying out three-time crystallization on mother liquor obtained by sequentially carrying out one-effect, two-effect, three-effect and four-effect evaporation on a salt solution subjected to adsorption, oxidation and decoloration.

The dissolving means that the industrial waste salt is stirred and fully dissolved, and then insoluble substances are removed to obtain a first-grade clear salt solution.

The chemical pre-impurity removal means that a first-stage clarified salt solution is subjected to precipitation treatment to obtain a second-stage clarified salt solution; preferably, the number of the precipitation treatments is not less than 2.

The deep impurity removal means that the secondary clarified salt solution is sequentially subjected to microfiltration membrane, resin adsorption and degassing treatment to obtain a degassed salt solution.

The resin is chelate resin and is regenerated periodically;

preferably, the degassing treatment is to adjust the pH of the salt solution after the resin treatment, so that the volatile weak acid radical ions are converted into gas, and then the gas is removed by blowing, so as to obtain a degassed salt solution.

The organic matter concentration reduction means that the degassed salt solution intercepts organic matters through a separation membrane to obtain purified salt solution and concentrated solution.

The adsorption oxidation decoloration refers to that purified salt solution is adsorbed by an accumulation type filler and then is fully mixed with an oxidant for reaction, and the chromophoric group and part of organic matters of the organic matters are removed;

preferably, the stacking filler is at least one of fiber balls, activated carbon and polypropylene (PP) soft filler; the oxidant is at least one of ozone, Fenton reagent and hydrogen peroxide.

The concentrated solution is washed by condensed water generated in multi-effect evaporation crystallization, and the washed condensed water is circulated to the dissolving step to dissolve industrial salt.

The invention also provides equipment suitable for the industrial waste salt recycling treatment method, which comprises a dissolving tank, a chemical pre-impurity removal system, a deep impurity removal system, an organic matter concentration and reduction system, an adsorption oxidation system and an evaporation crystallization system which are sequentially connected;

the chemical pre-impurity-removing system comprises a primary reactor, a primary clarifier, a secondary reactor, a secondary clarifier and a matched dosing device;

the deep impurity removal system comprises a microfiltration device, a resin adsorption device and a degassing device;

the organic matter concentration and reduction system is a membrane separation device;

the adsorption oxidation system comprises a filler adsorption device and an oxidation device;

the evaporative crystallization system is a multi-effect evaporative crystallization device.

The technical scheme of the invention has the following advantages:

1. the invention provides a resource treatment method of industrial waste salt, which comprises the following steps: sequentially dissolving industrial waste salt, chemically pre-removing impurities, deeply removing impurities, concentrating and reducing organic matters, carrying out adsorption oxidation and decolorization, and carrying out multi-effect evaporation and crystallization to respectively obtain sodium sulfate, sodium chloride and sodium nitrate crystals; wherein the crystallization temperature of the sodium sulfate is 75-85 ℃; the crystallization temperature of the sodium chloride is 60-70 ℃; the crystallization temperature of sodium nitrate is 45-55 ℃. Organic matters and other impurities in the industrial waste salt are removed firstly by adopting the steps, then salt separation crystallization is realized by temperature control in the evaporation process, namely, the salt separation crystallization is carried out by utilizing the difference of three-phase common saturation points of sodium chloride, sodium nitrate and sodium sulfate at different temperatures and the solubility of each salt, and the purity and whiteness of the sodium chloride, the sodium nitrate and the sodium sulfate obtained by the salt separation crystallization all reach the industrial grade standard and can be directly applied, so that the industrial salt treated by the resource treatment method of the industrial waste salt provided by the invention is effectively utilized.

2. According to the method for recycling the industrial waste salt, a two-stage pre-impurity removal mode, namely a treatment technology combining chemical impurity removal, microfiltration membrane and resin adsorption, is adopted, so that the difficulty and cost of the pre-treatment of the industrial waste salt are effectively reduced, and heavy metal and impurity ions in the industrial waste salt are purified.

3. According to the method for recycling the industrial waste salt, most organic matters in the industrial waste salt can be removed by adopting a separation membrane interception mode, so that the quality of a final product is ensured; and the filler added in the subsequent adsorption oxidation decoloration process can adsorb organic matters with chromophoric groups, plays a part in decoloration, and also has adsorption effect on phosphorus, ammonia, nitrogen and the like in the solution, thereby further ensuring the quality of the final product.

4. According to the resource treatment method for the industrial waste salt, the condensed water generated in the multi-effect evaporation crystallization process is used for washing the concentrated solution generated after the organic matters are concentrated and reduced, so that the salt in the concentrated solution can be recovered, and the problems of coking, slagging and the like of an incinerator caused by incineration of the concentrated solution containing salt are avoided, so that the incineration cannot be normally carried out; and the washed condensed water is circulated to the dissolving step to dissolve the industrial salt, so that the multistage recycling of the condensed water is realized, and the resource waste and the secondary pollution are avoided.

5. The equipment suitable for the industrial waste salt recycling treatment method comprises a dissolving tank, a chemical pre-impurity removal system, a deep impurity removal system, an organic matter concentration and reduction system, an adsorption oxidation system and an evaporative crystallization system which are sequentially connected; by adopting the equipment, organic matters and other impurities in the industrial waste salt are removed firstly, and then salt separation crystallization is realized by temperature control in the evaporation process, namely, salt separation crystallization is carried out by utilizing the difference of three-phase common saturation points of sodium chloride, sodium nitrate and sodium sulfate at different temperatures and the solubility of each salt, and the purity and whiteness of the sodium chloride, the sodium nitrate and the sodium sulfate obtained by the salt separation crystallization all reach the industrial grade standard and can be directly applied, so that the industrial salt treated by the resource treatment method of the industrial waste salt provided by the invention is effectively utilized.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.

FIG. 1 is a process flow diagram of a method for recycling industrial waste salts according to the present invention;

FIG. 2 is a flow chart of the organic material concentration reduction step in the present invention;

FIG. 3 is a flow chart of the step of decolorizing by adsorption and oxidation in the present invention;

FIG. 4 is a flow chart of the apparatus for the method of recycling industrial waste salts according to the present invention.

Detailed Description

The following examples are provided to further understand the present invention, not to limit the scope of the present invention, but to provide the best mode, not to limit the content and the protection scope of the present invention, and any product similar or similar to the present invention, which is obtained by combining the present invention with other prior art features, falls within the protection scope of the present invention.