阅读说明：本技术 一种含盐有机废水结晶残盐的处理方法及其用途 (Treatment method and application of salt-containing organic wastewater crystallization residual salt ) 是由 徐红彬 陈辉霞 唐海燕 张笛 徐世红 孙继远 张红玲 曹宏斌 于 2019-09-06 设计创作，主要内容包括：本发明涉及一种含盐有机废水结晶残盐的处理方法及其用途。该处理方法包括以下步骤：(1)将含盐有机废水结晶残盐与硫酸混合加热,使得所述结晶残盐中的无机盐转化成硫酸盐,得到含硫酸盐的杂盐；(2)将步骤(1)所述含硫酸盐的杂盐与固化剂混合,进行热解固化,得到矿物态复合化合物。采用该处理方法得到的所述矿物态复合化合物可以作为一般工业固体废物综合利用。本发明所述的处理方法原料廉价易得、工艺简单、成本较低,能实现所述结晶残盐中有机物的高效去除和水溶盐的安全固定,并实现所述结晶残盐的资源化利用,有利于工业化实施。(The invention relates to a treatment method of salt-containing organic wastewater crystallization residual salt and application thereof. The processing method comprises the following steps: (1) mixing and heating salt-containing organic wastewater crystallization residual salt and sulfuric acid to convert inorganic salt in the crystallization residual salt into sulfate, so as to obtain mixed salt containing sulfate; (2) and (2) mixing the sulfate-containing mixed salt obtained in the step (1) with a curing agent, and carrying out pyrolysis curing to obtain a mineral composite compound. The mineral state compound obtained by the treatment method can be comprehensively utilized as general industrial solid waste. The treatment method has the advantages of cheap and easily-obtained raw materials, simple process and lower cost, can realize the efficient removal of organic matters in the crystallized residual salt and the safe fixation of water-soluble salt, realizes the resource utilization of the crystallized residual salt, and is beneficial to industrial implementation.)

1. The method for treating the residual salt from the crystallization of the salt-containing organic wastewater is characterized by comprising the following steps of:

(1) Mixing and heating salt-containing organic wastewater crystallization residual salt and sulfuric acid to convert inorganic salt in the crystallization residual salt into sulfate, so as to obtain mixed salt containing sulfate;

(2) And (2) mixing the sulfate-containing mixed salt obtained in the step (1) with a curing agent, and carrying out pyrolysis curing to obtain a mineral composite compound.

2. The method for treating the salt residues from the crystallization of salt-containing organic wastewater according to claim 1, wherein the inorganic salt in the salt residues from step (1) comprises any one or a mixture of at least two of halide, sulfate, sulfite, metal sulfide, nitrate or nitrite;

Preferably, the inorganic salt in the residual salt from the crystallization in step (1) comprises any one or a mixture of at least two of sodium chloride, sodium sulfate, sodium sulfite, sodium sulfide, sodium nitrate, sodium nitrite, potassium chloride, potassium sulfate, potassium sulfite, potassium sulfide, potassium nitrate and potassium nitrite;

Preferably, the TOC content of the residual salt crystallized in the step (1) is 50-100000 mg/kg;

Preferably, the content of heavy metal in the residual salt from the step (1) is 0.5-10000 mg/kg;

preferably, the heavy metal comprises any one or a mixture of at least two of copper, lead, zinc, tin, nickel, cobalt, antimony, mercury, cadmium, bismuth, chromium, vanadium, thallium or manganese.

3. The method for treating the salt residue from the crystallization of the salt-containing organic wastewater as claimed in claim 1 or 2, wherein the mass fraction of pure H ₂ SO ₄ in the sulfuric acid in the step (1) is not less than 70%;

preferably, the adding amount of the sulfuric acid in the step (1) is 1-5 times, preferably 2-3 times of the mass of the residual salt of crystallization.

4. The method for treating the salt residue from the crystallization of the salt-containing organic wastewater as claimed in any one of claims 1 to 3, wherein the heating time in step (1) is 1-5 h, preferably 1-3 h;

Preferably, the heating temperature in the step (1) is 100-600 ℃, and preferably 200-500 ℃.

5. The method for treating the salt in the salt-containing organic wastewater crystallization residual salt according to any one of claims 1 to 4, characterized in that the curing agent in the step (2) is a mineral containing silicon and/or aluminum;

Preferably, the mineral containing silicon and/or aluminum comprises any one or a mixture of at least two of clay, kaolin, silica sand, alumina, bauxite, red mud, fly ash or beneficiation tailings, and further preferably any one or a mixture of at least two of kaolin, red mud or fly ash;

Preferably, the addition amount of the curing agent in the step (2) is 2-8 times, preferably 3-6 times of the mass of the residual salt.

6. The method for treating the salt in the salt-containing organic wastewater crystal residue according to any one of claims 1 to 5, wherein the step (2) is followed by grinding to obtain a grinding mixture;

Preferably, the mixed particle size of the grinding mixture is 10-200 meshes, and preferably 20-100 meshes.

7. the method for treating the salt residue from the crystallization of the salt-containing organic wastewater according to any one of claims 1 to 6, wherein the temperature of the pyrolysis solidification in the step (2) is 800-1500 ℃, preferably 950-1300 ℃;

preferably, the pyrolysis curing time in the step (2) is 0.5-5 h, preferably 1-2 h;

Preferably, the mineral complex compound in step (2) comprises any one or a mixture of at least two of feldspar, jadeite, leucite, nepheline, mica and illite.

8. the method for treating the salt residue from the crystallization of the salt-containing organic wastewater as claimed in any one of claims 1 to 7, wherein the tail gas generated in the steps (1) and (2) is discharged after reaching the standard;

Preferably, the tail gas treatment method comprises any one or at least two treatment methods of alkali absorption, dust removal, desulfurization, denitration and dioxin removal.

9. The method for treating the salt residue from the crystallization of the salt-containing organic wastewater as claimed in any one of claims 1 to 8, which comprises the following steps:

(1) Mixing the residual crystallized salt with 1-5 times of sulfuric acid with the mass fraction of more than or equal to 70%, and heating at 100-600 ℃ for 1-5 hours to obtain the mixed salt containing sulfate;

(2) mixing the sulfate-containing mixed salt obtained in the step (1) with 2-8 times of a curing agent, grinding to obtain a ground mixture with the mixed particle size of 10-200 meshes, and then performing pyrolysis curing at 800-1500 ℃ for 0.5-5 h to obtain the mineral composite compound.

10. use of the mineral complex compound obtained by the treatment method according to any one of claims 1 to 9, wherein the mineral complex compound can be used as general industrial solid waste for comprehensive utilization, including but not limited to roadbed materials, building lightweight aggregates, building block materials, ceramic materials or glass materials.

Technical Field

The invention relates to the technical field of solid waste disposal, in particular to a treatment method of salt-containing organic wastewater crystallization residual salt and application thereof.

Background

The method comprises the steps of removing organic matters in the salt-containing organic wastewater and separating and treating soluble salt substances to obtain a final treatment target of the salt-containing organic wastewater, wherein the salt-containing organic wastewater contains a large amount of soluble inorganic salts such as Cl ^- , Na ⁺, SO ₄ ^2- , Ca ²⁺ and the like in the wastewater treatment process of chemical industries such as coal chemical industry, chemical fertilizer industry, pesticide industry, pharmaceutical industry and the like.

the waste salt is treated by landfill disposal or high-temperature incineration. Due to the moisture absorption of the waste salt, the risk of redissolution exists in the processes of storage, transportation and landfill, and secondary pollution is easily caused. Therefore, the landfill disposal needs to adopt extremely strict closed landfill requirements to meet the standard of safety and environmental protection. Researchers have conducted a great deal of research based on the high-temperature incineration method of waste salt, and disclosed various methods for treating waste salt by using different incineration processes, for example, CN106801874A discloses a method for treating industrial waste salt, which comprises mixing microwave absorbing medium particles and industrial waste salt particles in a microwave processor, heating and degrading pollutants in the waste salt by using microwave energy under the condition of air atmosphere and continuous stirring and mixing, elutriating the residual waste salt with water to recover NaCl, and recycling the microwave absorbing medium particles. CN105712421A discloses a method for harmlessly treating coal chemical industry organic high-salt wastewater by a two-stage heating-oxygen-enriched combustion method, which comprises the steps of putting the coal chemical industry organic high-salt wastewater into an electric furnace, carrying out two-stage heating to fully melt the wastewater, and then blowing oxidizing gas into a molten pool to carry out oxygen-enriched combustion on organic matters in the organic high-salt wastewater to obtain nontoxic molten waste salt. CN108571736A discloses a method for harmlessly treating high-salinity wastewater by using fly ash as an additive, which comprises the steps of placing the high-salinity wastewater in an electric furnace, heating materials, adding a certain amount of fly ash into the materials when the materials are in a molten state, and blowing oxidizing gas into a molten pool through a spray gun to perform oxygen-enriched combustion of organic pollutants and the like, so as to realize the harmlessness treatment of the organic pollutants and the like in the high-salinity wastewater and the complex conversion of sodium salt and potassium salt. However, these treatment methods often have the problems of waste salt melting, incomplete removal of organic matter and heavy metal impurities, mixing of various inorganic salts, and the like, so that the resource utilization after the treatment of the waste salt still cannot be realized.

The salt-containing organic wastewater crystallization residual salt is residual salt generated in the process of recycling waste salt through fractional crystallization, is solid hazardous waste containing various inorganic salts such as sodium chloride, sodium sulfate, sodium sulfite, sodium sulfide, sodium nitrate, sodium nitrite, potassium chloride, potassium sulfate, potassium sulfite, potassium sulfide, potassium nitrate, potassium nitrite and the like, contains a large amount of organic matters and various heavy metals, and has strong pungent smell. Because the components are complex, the toxicity is high, the impurity content is higher, the resource treatment is more difficult to realize, and the country manages according to the hazardous waste. Therefore, the development of a new method which has simple process, lower cost and safe disposal is of great significance.

Disclosure of Invention

aiming at the defects of the prior art, the invention relates to a method for treating salt-containing organic wastewater crystallization residual salt, and the mineral compound obtained by the treatment method can be used for comprehensive utilization of general industrial solid waste or can be directly used as a downstream industrial raw material.

One purpose of the invention is to provide a method for treating salt residue from salt-containing organic wastewater crystallization, which comprises the following steps:

(1) Mixing and heating salt-containing organic wastewater crystallization residual salt and sulfuric acid to convert inorganic salt in the crystallization residual salt into sulfate, so as to obtain mixed salt containing sulfate;

(2) and (2) mixing the sulfate-containing mixed salt obtained in the step (1) with a curing agent, and carrying out pyrolysis curing to obtain a mineral composite compound.

as a preferred technical solution of the present invention, the inorganic salt in the residual crystallization salt in step (1) includes any one or a mixture of at least two of halide, sulfate, sulfite, metal sulfide, nitrate or nitrite, and typical but non-limiting examples of the mixture are: mixtures of halides and nitrates, mixtures of halides and sulfates, mixtures of sulfates, sulfites, and metal sulfides, or mixtures of halides, nitrates, and nitrites, and the like.

preferably, the inorganic salt in the residual salt from the crystallization in step (1) includes any one or a mixture of at least two of sodium chloride, sodium sulfate, sodium sulfite, sodium sulfide, sodium nitrate, sodium nitrite, potassium chloride, potassium sulfate, potassium sulfite, potassium sulfide, potassium nitrate, or potassium nitrite, and the mixture is typically but not limited to: mixtures of sodium chloride, potassium chloride and sodium nitrate, mixtures of sodium chloride, sodium sulfate and sodium sulfite, mixtures of sodium sulfate, sodium nitrate and sodium nitrite or mixtures of sodium sulfide, potassium chloride and potassium sulfate, and the like.

preferably, the TOC content of the residual salt crystallized in step (1) is 50-100000 mg/kg, such as 50mg/kg, 100mg/kg, 500mg/kg, 1000mg/kg, 5000mg/kg, 10000mg/kg, 50000mg/kg or 100000mg/kg, but is not limited to the recited values, and other non-recited values within the range are equally applicable.

Preferably, the residual salt of the crystallization in step (1) has a heavy metal content of 0.5 to 10000mg/kg, such as 0.5mg/kg, 10mg/kg, 100mg/kg, 1000mg/kg, 5000mg/kg or 10000mg/kg, but not limited to the values listed, and other values not listed in the range of the values are also applicable.

Preferably, the heavy metal comprises any one of copper, lead, zinc, tin, nickel, cobalt, antimony, mercury, cadmium, bismuth, chromium, vanadium, thallium or manganese or a mixture of at least two of these, typical but non-limiting examples being: mixtures of copper, nickel and cobalt, mixtures of lead, antimony and mercury, mixtures of tin, cadmium and bismuth or mixtures of chromium, vanadium, thallium and manganese, etc.

the invention utilizes the principle that the acid which is difficult to volatilize can prepare the volatile acid to convert the inorganic salt in the salt residue of the salt-containing organic wastewater into sulfate, and particularly separates and treats chloride ions and nitrate ions in a gas form. Taking sodium chloride and sodium nitrate as examples, the specific equation is as follows:

2NaCl (solid) + H ₂ SO ₄ (concentrated) ═ Na ₂ SO ₄ +2HCl ≠ H ═ Na

2NaNO ₃ (solid) + H ₂ SO ₄ (concentrated) ═ Na ₂ SO ₄ +2HNO ₃ ≠ H

As a preferable technical scheme of the invention, the mass fraction of pure H ₂ SO ₄ in the sulfuric acid in the step (1) is more than or equal to 70 percent.

preferably, the amount of the sulfuric acid added in the step (1) is 1 to 5 times, such as 1 time, 1.5 times, 2 times, 2.5 times, 2.7 times, 3 times, 3.5 times, 4 times or 5 times, etc., more preferably 2 to 3 times, such as 2 times, 2.1 times, 2.3 times, 2.5 times, 2.7 times, 2.9 times or 3 times, etc., of the mass of the residual salt of crystallization, but is not limited to the recited values, and other values not recited in the above numerical range are also applicable.

in a preferred embodiment of the present invention, the heating time in step (1) is 1 to 5 hours, such as 1 hour, 1.5 hours, 2 hours, 2.5 hours, 3 hours, 3.5 hours, 4 hours, 4.5 hours or 5 hours, and more preferably 1 to 3 hours, such as 1 hour, 1.4 hours, 1.7 hours, 1.9 hours, 2 hours, 2.3 hours, 2.6 hours, 2.8 hours or 3 hours, but is not limited to the recited values, and other values not recited in the above numerical range are also applicable.

Preferably, the heating temperature in step (1) is 100 to 600 ℃, such as 100 ℃, 200 ℃, 300 ℃, 400 ℃, 500 ℃ or 600 ℃, and more preferably 200 to 500 ℃, such as 200 ℃, 250 ℃, 300 ℃, 340 ℃, 400 ℃, 460 ℃ or 500 ℃, but not limited to the recited values, and other unrecited values within the above numerical range are also applicable.

as a preferable technical scheme of the invention, the curing agent in the step (2) is a mineral containing silicon and/or aluminum.

Preferably, the silicon and/or aluminium containing mineral comprises any one or a mixture of at least two of clay, kaolin, silica sand, alumina, bauxite, red mud, fly ash or mill tailings, typical but non-limiting examples of which are: a mixture of clay and kaolin, a mixture of fly ash and silica sand, a mixture of silica sand and mineral processing tailings, a mixture of silica sand, alumina and bauxite or a mixture of alumina, bauxite, red mud and fly ash, etc., and further preferably any one or a mixture of at least two of kaolin, red mud or fly ash, the typical but non-limiting examples of which are: mixtures of kaolin and red mud, mixtures of kaolin and fly ash or mixtures of red mud and fly ash, and the like.

the invention realizes the safe solidification of the residual salt by adding a certain amount of curing agent to ensure that the residual salt after the reaction with sulfuric acid is pyrolyzed and solidified at high temperature and convert water-soluble crystalline ionic compounds into water-insoluble mineral complex oxides, and takes the pyrolysis and solidification reaction of sulfate and silica sand (SiO ₂) and kaolin (Al ₂ O ₃.2SiO ₂) to generate potash feldspar (K ₂ O.Al ₂ O ₃.6SiO ₂), albite (Na ₂ O.Al ₂ O ₃.6SiO ₂), leucite (KAlSi ₂ O ₆) and jadeite (NaAlSi ₂ O ₆) as examples, and the specific equations are as follows:

K₂O·SO₃+Al₂O₃·2SiO₂+4SiO₂＝K₂O·Al₂O₃·6SiO₂+SO₃↑

Na₂O·SO₃+Al₂O₃·2SiO₂+4SiO₂＝Na₂O·Al₂O₃·6SiO₂+SO₃↑

K₂O·SO₃+Al₂O₃·2SiO₂+2SiO₂＝2KAlSi₂O₆+SO₃↑

Na₂O·SO₃+Al₂O₃·2SiO₂+2SiO₂＝2NaAlSi₂O₆+SO₃↑

Preferably, the amount of the curing agent added in step (2) is 2 to 8 times, such as 2 times, 3 times, 3.5 times, 4 times, 4.5 times, 5 times, 5.5 times, 6 times, 7 times or 8 times, etc., more preferably 3 to 6 times, such as 3 times, 3.3 times, 3.5 times, 4 times, 4.5 times, 4.7 times, 5 times, 5.3 times, 5.5 times or 6 times, etc., of the mass of the sulfate-containing miscellaneous salt, but is not limited to the recited values, and other values not recited in the above numerical range are also applicable.

As a preferable technical scheme of the invention, grinding is carried out after the mixing in the step (2) to obtain a grinding mixture.

Preferably, the mixed particle size of the grinding mixture is 10 to 200 mesh, such as 10 mesh, 20 mesh, 50 mesh, 70 mesh, 100 mesh, 130 mesh, 150 mesh or 200 mesh, and more preferably 20 to 100 mesh, such as 20 mesh, 30 mesh, 40 mesh, 50 mesh, 60 mesh, 70 mesh, 80 mesh, 90 mesh or 100 mesh, but is not limited to the enumerated values, and other unrecited values within the above numerical range are also applicable.

In a preferred embodiment of the present invention, the pyrolysis curing temperature in step (2) is 800 to 1500 ℃, such as 800 ℃, 900 ℃, 1000 ℃, 1100 ℃, 1200 ℃, 1300 ℃, 1400 ℃, or 1500 ℃, and more preferably 950 to 1300 ℃, such as 950 ℃, 1000 ℃, 1050 ℃, 1100 ℃, 1150 ℃, 1200 ℃, 1250 ℃, or 1300 ℃, but is not limited to the above-mentioned values, and other values not listed in the above-mentioned value range are also applicable.

preferably, the pyrolysis curing time in the step (2) is 0.5 to 5 hours, such as 0.5 hour, 1 hour, 1.5 hour, 2 hours, 3 hours, 3.5 hours, 4 hours, 4.5 hours or 5 hours, etc., more preferably 1 to 2 hours, such as 1 hour, 1.2 hours, 1.4 hours, 1.5 hours, 1.7 hours, 1.9 hours or 2 hours, etc., but not limited to the enumerated values, and other non-enumerated values in the above numerical range are also applicable.

Preferably, the mineral complex compound of step (2) comprises any one or a mixture of at least two of feldspar, jadeite, leucite, nepheline, mica or illite, typical but non-limiting examples of which are: a mixture of feldspar and leucite, a mixture of feldspar and mica, a mixture of jadeite and illite, a mixture of feldspar, nepheline and mica, or a mixture of jadeite, leucite and mica, and the like.

As a preferable technical scheme of the invention, the tail gas generated in the step (1) and the step (2) is discharged after reaching the standard.

Preferably, the tail gas treatment method includes a treatment method by any one or at least two of alkali absorption, dust removal, desulfurization, denitration, and dioxin removal, and typical but non-limiting examples of the treatment method are: a treatment method of alkali absorption, desulfurization and denitration, a treatment method of dust removal, desulfurization and denitration, a treatment method of desulfurization, denitration and dioxin removal, a treatment method of alkali absorption, desulfurization, denitration and dioxin removal, or the like.

As a preferable technical solution of the present invention, the processing method includes the steps of:

(1) mixing the residual crystallized salt with 1-5 times of sulfuric acid with the mass fraction of more than or equal to 70%, and heating at 100-600 ℃ for 1-5 hours to obtain the mixed salt containing sulfate;

(2) Mixing the sulfate-containing mixed salt obtained in the step (1) with 2-8 times of a curing agent, grinding to obtain a ground mixture with the mixed particle size of 10-200 meshes, and then performing pyrolysis curing at 800-1500 ℃ for 0.5-5 h to obtain the mineral composite compound.

Another object of the present invention is to provide a use of the mineral complex compound obtained by the treatment method of the present invention, which can be used as general industrial solid waste for comprehensive utilization, including but not limited to roadbed material, building lightweight aggregate, building block material, ceramic material or glass material.

Compared with the prior art, the invention has at least the following beneficial effects:

(1) According to the treatment method, inorganic salts in the salt residue of the salt-containing organic wastewater are converted into sulfate through sulfuric acid, and particularly, chloride ions and nitrate ions are separated in a gas form, so that the corrosion of chloride ions to equipment and the formation of water-soluble ionic compounds in a high-temperature curing process are avoided;

(2) According to the treatment method, through pyrolysis and solidification, organic matters in the salt-containing organic wastewater crystallization residual salt are completely decomposed and the residual salt is safely solidified, so that the moisture absorption and dissolution of water-soluble salt are reduced, and the leaching risk of toxic and harmful substances such as impurity organic matters and heavy metals in the residual salt is reduced;

(3) the solidification rate of the water-soluble salt in the mineral compound obtained by the invention is more than or equal to 99 percent, the TOC in the water leaching solution (1:10) of the mineral compound is less than or equal to 0.5mg/L, and the heavy metal content in the leaching solution meets the pollution control index limit value of a common industrial solid waste landfill.

(4) The mineral state compound after pyrolysis and solidification can be comprehensively utilized as common industrial solid waste, so that the pollution of the compound to the environment can be eliminated, and the resource utilization and circular economy of byproducts can be realized;

(5) The treatment method has the advantages of cheap and easily-obtained raw materials, simple process and lower cost, and is beneficial to industrial implementation.

Drawings

FIG. 1 is a flow chart of the method for treating residual salt from crystallization of salt-containing organic wastewater

Detailed Description

for the purpose of facilitating an understanding of the present invention, the present invention will now be described by way of examples. It should be understood by those skilled in the art that the examples are only for the understanding of the present invention and should not be construed as the specific limitations of the present invention.

The following example is to mix and heat the salt-containing organic wastewater crystallization residual salt with sulfuric acid, so that the inorganic salt in the crystallization residual salt is converted into sulfate, then mix the sulfate-containing mixed salt with a curing agent, and perform pyrolysis and curing to obtain a mineral composite compound. The mineral state compound can be comprehensively utilized as general industrial solid waste.