阅读说明：本技术 一种利用余热从酸洗废液中制备工业盐的方法 (Method for preparing industrial salt from pickling waste liquid by using waste heat ) 是由 石海信 陆贻春 冯晓东 李�根 于 2021-10-09 设计创作，主要内容包括：本发明公开了一种利用余热从酸洗废液中制备工业盐的方法,利用钢铁酸洗后的构件浸入(435±1)℃锌液池中热镀锌后,镀件出锅用水冷却,将直接冷却水的余热(水温65-75℃),以及在利用片碱配碱液产生的溶解热,碱与酸洗废液发生中和反应的中和热等将循环余热水(水温70-90℃)对工艺衍生盐水进行加热蒸发,使工艺衍生盐浓缩,最终结晶析出工业盐,结晶的工业盐可作为工业资源利用。(The invention discloses a method for preparing industrial salt from pickling waste liquid by using waste heat, which comprises the steps of immersing a member subjected to pickling with steel acid into a (435 +/-1) DEG C zinc liquid pool for hot galvanizing, taking a plated member out of a pot, cooling with water, heating and evaporating process derivative salt water by using circulating waste heat water (water temperature is 70-90 ℃) due to the neutralization heat generated by a sheet alkali and an alkali solution, the neutralization heat generated by the neutralization reaction of alkali and the pickling waste liquid, and the like, so that the process derivative salt is concentrated, and finally crystallizing and precipitating the industrial salt, wherein the crystallized industrial salt can be used as an industrial resource.)

1. A method for preparing industrial salt from pickling waste liquid by using waste heat is characterized by comprising the following steps: the method comprises the following steps:

1) adding pure water into the interlayer alkali preparation kettle, adding caustic soda flakes solid, stirring to prepare 25-50% alkali liquor (sodium hydroxide solution) by mass fraction, releasing 43.47kJ/mol of dissolution heat in the dissolving process of caustic soda flakes, heating interlayer circulating residual heat water in the interlayer alkali preparation kettle to 50-60 ℃, leading out, pumping to the interlayer oxidation precipitation kettle;

2) pumping pickling waste liquid into an interlayer oxidation precipitation kettle, adding an oxidant under the condition that the pH value of the pickling waste liquid is less than or equal to 1, and oxidizing and removing organic matters in the pickling waste liquid to obtain a first mixed liquid only containing metal cations such as hydrochloric acid, chloride ions, iron, zinc and the like; the oxidant is 13-20% of hydrogen peroxide by mass, and the mass ratio of the hydrogen peroxide to organic matters in the pickling waste liquid is (2.0-2.8): 1;

3) adding the alkali liquor (sodium hydroxide solution) prepared in the step 1) into the first mixed solution in the interlayer oxidation precipitation kettle, adjusting the pH value of the solution to 7.3-8.6 by using hydrochloric acid, converting metal cations such as iron, zinc and the like in the first mixed solution into insoluble metal hydroxides, precipitating the insoluble metal hydroxides from the solution, performing filter pressing to obtain a filtrate as a second mixed solution, heating the interlayer residual hot water of the interlayer alkali preparation kettle to 70-90 ℃ by using reaction heat released in the acid-base neutralization reaction process, and leading the interlayer residual hot water of the interlayer alkali preparation kettle out to an interlayer of a brine evaporation tank for recycling; the mass ratio of the alkali liquor to the pickling waste liquor is (0.8-1.3) to 1, and the conductivity of the obtained second mixed liquor is more than 20000 mu s/cm;

4) passing the second mixed solution through a catcher filled with amphoteric polymer resin, allowing the catcher to catch sodium ions, chloride ions and other ions in the mixed solution, reducing the conductivity of water discharged from the catcher, indicating that the ion catcher is in a saturated catching state when the conductivity of the solution discharged from the catcher is similar to that of the second mixed solution, and performing selective back washing on the amphoteric polymer resin for 3-4 times by using pure water to obtain a back washing solution, wherein the back washing solution is a sodium chloride solution with the mass fraction of 10-18%;

5) conveying the third mixed solution to an interlayer salt water evaporation tank by a pump, and evaporating under the circulating heating of interlayer residual heat water in the interlayer salt water evaporation tank to obtain a fourth mixed solution; the fourth mixed solution is concentrated brine, and the mass fraction of sodium chloride is 23-25%;

6) and (3) introducing the fourth mixed solution into an interlayer strong brine crystallization tank, evaporating and concentrating to separate out salt crystals, collecting the crystals after crystals with the thickness of 1-2cm are separated out from the bottom of the crystallization tank to obtain an industrial salt product, and inspecting and packaging to obtain the industrial salt with the quality meeting the secondary standard of the solarization industrial salt in the industrial salt standard (GB/T5462-.

2. The method for preparing industrial salt from the pickling waste liquid by using the waste heat as claimed in claim 1, wherein the method comprises the following steps: the interlayer alkali-mixing kettle in the step 1) is a cylindrical alkali-mixing kettle with mechanical stirring slurry, the diameter and height of an inner container and an outer container are phi (70-130) cmX (100) cm and 150cm, the inner container is made of 316 stainless steel, the wall thickness of a steel plate is 0.3-0.5mm, the outer container is made of engineering plastic, the interlayer thickness is 4-8cm, a circulating residual hot water inlet pipe is arranged at a position 10-20cm below the top layer of the outer container, and a circulating residual hot water outlet pipe is arranged at a position 5-10cm away from the bottom end of the outer container.

3. The method for preparing industrial salt from the pickling waste liquid by using the waste heat as claimed in claim 1, wherein the method comprises the following steps: the interlayer oxidation precipitation kettle in the step 2) is made of 316 stainless steel, the diameters and heights of the inner container and the outer cylinder are phi (110-; the adding position of the oxidant is the bottom of the inner container, 3-5 nozzles are arranged in a delta shape, and the flow rate of the medicine adding liquid is controlled to be 5-15 mL/min.

4. The method for preparing industrial salt from the pickling waste liquid by using the waste heat as claimed in claim 1, wherein the method comprises the following steps: the amphoteric polymer resin in the step 4) is a polymer containing anions and cations in molecules, can adsorb various anions and cations in water, and can selectively elute the adsorbed chloride ions and sodium ions by pure water backwashing so as to regenerate the resin.

5. The method for preparing industrial salt from the pickling waste liquid by using the waste heat as claimed in claim 1, wherein the method comprises the following steps: the interlayer salt water evaporation tank in the step 5) is (10-14) mX (3-4) mX (0.2-0.4) m, the inner container is made of 304 stainless steel materials, the thickness of the steel plate is 0.4-0.6mm, the outer container is made of carbon steel materials, the thickness of the carbon steel is 4-20mm, and the thickness of the interlayer is 10-16 cm; the fourth mixed solution in the step 5) is concentrated brine obtained by evaporating water by using interlayer residual heat water of an interlayer brine evaporation pool as a heat source, and the mass fraction of sodium chloride is 23-25%.

6. The method for preparing industrial salt from the pickling waste liquid by using the waste heat as claimed in claim 1, wherein the method comprises the following steps: the interlayer strong brine crystallization tank in the step 6) is (6-8) mX (6-10) mX (0.2-0.4) m, the inner container is made of 304 stainless steel materials, the thickness of the steel plate is 0.4-0.6mm, the outer cylinder is made of carbon steel materials, the thickness of the carbon steel is 4-20mm, and the thickness of the interlayer is 5-10 cm; the crystal is collected by using a mechanical scraper.

[ technical field ] A method for producing a semiconductor device

The invention relates to the technical field of pickling waste liquid treatment, in particular to a method for preparing industrial salt from pickling waste liquid by utilizing waste heat.

[ background of the invention ]

When the surface of steel is subjected to hot galvanizing anti-corrosion treatment, a rust layer and oil stains on the surface of the steel need to be removed so that a good-quality metal zinc coating can be plated, the corrosion resistance of a steel member is enhanced, and the service life is prolonged. The pickling rust removal in the steel industry is most widely applied, the steel member is cleaned by acid liquor, and the acid liquor reacts with a rust layer on the surface of the member to achieve the purpose of rust removal.

In the early stage, common steel and low alloy steel components are cleaned by sulfuric acid, and from the late stage of the 80 th century, the pickling process of steel galvanizing enterprises mostly adopts hydrochloric acid as a pickling solution by taking the foreign advanced experience as a reference in China. The hydrochloric acid pickling has the characteristics of high speed, good quality, easy cleaning, low iron loss, no hydrogen embrittlement, good surface state and the like, and FeCl is contained in the hydrochloric acid pickling waste liquid₂About 15-25%, hydrochloric acid about 3-5%, some impurity metal ions and greasy dirt, the initial temperature of the pickling waste liquor is about 40-85 deg.C, and the density is about 1.1-1.4g/cm³. Currently, there are about 5000 large, medium and small steel plants in China, and these small and medium enterprises generate tens of tons to hundreds of tons of pickling waste liquid every day, and generate about millions of tons of waste liquid every year, and the amount of the pickling waste liquid is increasing along with the improvement of the yield and the quality of steel products. If the waste liquid is directly discharged without being treated, the environment is seriously polluted, and a large amount of resources such as iron, chlorine and the like are wasted.

Related researches are available, for example, chinese patent application No. cn201811317168.x discloses a resource recovery method of metal ions in pickling waste liquid, a product prepared therefrom and use thereof, the method comprising the steps of: (1) after the pickling waste liquid is settled and deslagged, adding soluble industrial salt and a precipitator, and adjusting the pH value of the waste liquid until metal ions in the waste liquid are completely precipitated to obtain pickling waste residues; (2) carrying out ball milling and extrusion processes on the acid pickling waste residue obtained in the step (1) to prepare an acid gas adsorbent; the acid gas adsorbent obtained by the invention is used for H₂S、SO₂The method has good adsorption effect, and the adsorbent product is prepared by taking the pickling waste liquid as a raw material, so that the resource recycling of metal ions in the pickling waste liquid is realized, the waste is prepared from waste, and the method has obvious environmental benefit.

For another example, chinese patent application No. CN201810126668.9 discloses a device and a method for treating and recycling pickling waste liquid, wherein a submersible pump is used to send the pickling waste liquid in a waste liquid tank to a waste liquid tank, and then the pickling waste liquid flows through a self-cleaning filter, an ultrafiltration membrane group and a reverse osmosis membrane group in sequence; discharging concentrated water obtained after concentration by the reverse osmosis membrane group into a concentrated water tank, performing iron removal treatment, sending into a waste liquid tank again, then passing through an ultrafiltration membrane group and the reverse osmosis membrane group, discharging concentrated water obtained after concentration into the concentrated water tank, then sending into a drying crystallizer, producing crystallized salt for recycling, and recycling fresh water obtained after concentration by the reverse osmosis membrane group; the chemical agent is added into the concentrated water tank through the chemical adding equipment, so that the treatment and resource utilization of the pickling waste liquid are realized, the consumption of the chemical agent is low, the solid sediment is low, and certain economic and environmental benefits are generated.

In summary, most of medium and small-sized steel enterprises mainly treat pickling waste liquid by an alkali-adding neutralization precipitation method, and have some research achievements and treatment technologies for resource utilization of ferrous solid mud generated by precipitation, for example, a dry method or a wet method is used for converting the ferrous solid mud into iron pigments such as iron oxide yellow, iron oxide red and the like, but no resource recycling treatment technology is found for a large amount of chloride ions in waste acid liquid, and usually, chlorine-containing soluble salt is diluted by a large amount of pure water and then discharged up to the standard, so that the surface seems to avoid serious pollution of the discharged wastewater to the water environment, actually, various soluble salts are diffused in a larger range, the cumulative effect of water environment pollution is larger, and meanwhile, the consumption of precious pure water resources and the waste of various soluble salt resources are increased.

[ summary of the invention ]

Aiming at the problem that the waste liquid generated by the prior galvanization pickling pretreatment in the steel industry generally only needs to be diluted by a large amount of pure water and then is discharged after reaching the standard, and various soluble salts are diffused in a wider range, the invention provides a method for preparing industrial salt from the pickling waste liquid by utilizing waste heat, which is a method for utilizing the waste heat of hot galvanizing cooling water, the method for preparing the industrial salt from the pickling waste liquid comprises the steps of taking the dissolution heat and the neutralization heat generated in the treatment process of the pickling waste liquid as heat sources to heat and evaporate a process derived salt aqueous solution, and separating out soluble process derived salt (the main component is sodium chloride) in the treatment process of the pickling waste liquid through evaporation, concentration and crystallization, so that a large amount of soluble salt in the metal pickling waste liquid is converted into industrial salt resources, the potential hazard of the soluble salt to a water body can be effectively eliminated, and the waste of a large amount of pure water is avoided.

The purpose of the invention is realized by the following technical scheme:

a method for preparing industrial salt from pickling waste liquid by using waste heat specifically comprises the following steps:

1) adding pure water into the interlayer alkali preparation kettle, adding caustic soda flakes solid, stirring to prepare 25-50% alkali liquor (sodium hydroxide solution) by mass fraction, releasing 43.47kJ/mol of dissolution heat in the dissolving process of caustic soda flakes, heating interlayer circulating residual heat water in the interlayer alkali preparation kettle to 50-60 ℃, leading out, pumping to the interlayer oxidation precipitation kettle;

2) pumping pickling waste liquid into an interlayer oxidation precipitation kettle, adding an oxidant under the condition that the pH value of the pickling waste liquid is less than or equal to 1, and oxidizing and removing organic matters in the pickling waste liquid to obtain a first mixed liquid only containing metal cations such as hydrochloric acid, chloride ions, iron, zinc and the like; the oxidant is 13-20% of hydrogen peroxide by mass, and the mass ratio of the hydrogen peroxide to organic matters in the pickling waste liquid is (2.0-2.8): 1;

3) adding the alkali liquor (sodium hydroxide solution) prepared in the step 1) into the first mixed solution in the interlayer oxidation precipitation kettle, adjusting the pH value of the solution to 7.3-8.6 by using hydrochloric acid, converting metal cations such as iron, zinc and the like in the first mixed solution into insoluble metal hydroxides, precipitating the insoluble metal hydroxides from the solution, performing filter pressing to obtain a filtrate as a second mixed solution, heating the interlayer residual hot water of the interlayer alkali preparation kettle to 70-90 ℃ by using reaction heat released in the acid-base neutralization reaction process, and leading the interlayer residual hot water of the interlayer alkali preparation kettle out to an interlayer of a brine evaporation tank for recycling; the mass ratio of the alkali liquor to the pickling waste liquor is (0.8-1.3) to 1, and the conductivity of the obtained second mixed liquor is more than 20000 mu s/cm;

4) passing the second mixed solution through a catcher filled with amphoteric polymer resin, allowing the catcher to catch sodium ions, chloride ions and other ions in the mixed solution, reducing the conductivity of water discharged from the catcher, indicating that the ion catcher is in a saturated catching state when the conductivity of the solution discharged from the catcher is similar to that of the second mixed solution, and performing selective back washing on the amphoteric polymer resin for 3-4 times by using pure water to obtain a back washing solution, wherein the back washing solution is a sodium chloride solution with the mass fraction of 10-18%;

5) conveying the third mixed solution to an interlayer salt water evaporation tank by a pump, and evaporating under the circulating heating of interlayer residual heat water in the interlayer salt water evaporation tank to obtain a fourth mixed solution; the fourth mixed solution is concentrated brine, and the mass fraction of sodium chloride is 23-25%;

6) and (3) introducing the fourth mixed solution into an interlayer strong brine crystallization tank, evaporating and concentrating to separate out salt crystals, collecting the crystals after crystals with the thickness of 1-2cm are separated out from the bottom of the crystallization tank to obtain an industrial salt product, and inspecting and packaging to obtain the industrial salt with the quality meeting the secondary standard of the solarization industrial salt in the industrial salt standard (GB/T5462-.

In the invention:

the interlayer alkali-blending kettle in the step 1) is a cylindrical alkali-blending kettle with mechanical stirring slurry, the diameter and height of an inner container and an outer container are determined by the daily-treatment acid-washing waste liquid amount, phi (70-130) cmX (100) cm and 150cm are used as the inner container, the inner container is made of 316 stainless steel, the wall thickness of a steel plate is 0.3-0.5mm, the outer container is made of engineering plastic (resistant to temperature of 120 ℃ and 200 ℃) and the interlayer thickness is 4-8cm, an interlayer residual hot water inlet pipe in the interlayer alkali-blending kettle is arranged at a position 10-20cm below the top layer of the outer container, and an interlayer residual hot water outlet pipe in the interlayer alkali-blending kettle is arranged at a position 5-10cm away from the bottom end of the outer container.

The interlayer oxidation precipitation kettle in the step 2) is made of 316 stainless steel, the diameters and the heights of the inner container and the outer cylinder are determined by the daily treatment pickling waste liquid amount, the preferable phi (110-; the adding position of the oxidant is the bottom of the inner container, 3-5 nozzles are arranged in a delta shape, and the flow rate of the medicine adding liquid is controlled to be 5-15 mL/min.

In the step 3), at 298.15 ℃, the standard molar formation enthalpy (neutralization heat) of the neutralization reaction of the alkali liquor and the hydrochloric acid is 179.067kJ/mol, and the neutralization heat heats the interlayer residual heat water from the interlayer alkali preparation kettle to 70-90 ℃.

The amphoteric polymer resin in the step 4) is a polymer containing anions and cations in molecules, can adsorb various anions and cations in water, and can selectively elute the adsorbed chloride ions and sodium ions by pure water backwashing so as to regenerate the resin.

The interlayer salt water evaporation tank in the step 5) is preferably (10-14) mX (3-4) mX (0.2-0.4) m, the inner container is made of 304 stainless steel materials, the thickness of a steel plate is 0.4-0.6mm, the outer cylinder is made of carbon steel materials, the thickness of the carbon steel is 4-20mm, and the thickness of an interlayer is 10-16 cm; the fourth mixed solution in the step 5) is concentrated brine obtained by evaporating water by using interlayer residual heat water of an interlayer brine evaporation pool as a heat source, and the mass fraction of sodium chloride is 23-25%.

The interlayer strong brine crystallization tank in the step 6) is preferably (6-8) mX (6-10) mX (0.2-0.4) m, the inner container is made of 304 stainless steel materials, the thickness of the steel plate is 0.4-0.6mm, the outer cylinder is made of carbon steel materials, the thickness of the carbon steel is 4-20mm, and the thickness of the interlayer is 5-10 cm; and 6) collecting the crystals, namely collecting the crystals by using a mechanical scraper and shoveling out the crystals in time so as to avoid influencing the heat transfer of hot water to the strong brine of the crystallization tank through the stainless steel inner container.

Compared with the prior art, the invention has the following advantages:

1. compared with the traditional solar salt drying technology, the method for preparing the industrial salt from the pickling waste liquid by utilizing the waste heat aims at the current situation that the steel production is continuously carried out, the galvanizing circulating cooling water is also necessary for the galvanizing production, the treatment of the pickling waste liquid is synchronous with the steel production, the waste heat of the galvanizing and pickling waste liquid treatment is continuously generated, if the waste heat is not utilized, the galvanizing and waste liquid treatment is influenced and utilized, and the temperature of each part is effectively controlled; the weather conditions of different places in China are different, the rainy weather is more generally in southern areas, and sunlight is easily influenced.

2. According to the method for preparing the industrial salt from the pickling waste liquid by utilizing the waste heat, the soluble salt can be crystallized and separated out to become the industrial salt, the industrial salt reaches the standard of solarization secondary industrial salt, a large amount of pure water is not required to be added, the soluble salt solution is diluted and then discharged, and a large amount of pure water is saved; the waste water containing soluble salt is evaporated by waste heat, so that the salt in the waste water is crystallized, purified and recycled as resources, the salt resource loss and the environmental pollution are avoided, and the harmless and zero-emission treatment of the soluble sodium salt in the pickling waste liquid is realized.

3. According to the method for preparing the industrial salt from the pickling waste liquid by using the waste heat, the heat sources used for evaporating the salt water are all derived from the dissolution heat and the neutralization heat of the pickling waste liquid treatment and the high-temperature cooling water generated in the steel galvanizing production process, and no additional electric energy or coal gas is required for heating, so that the comprehensive and effective utilization of the pickling waste liquid treatment waste heat and the zinc galvanizing production process waste heat is realized, and the dual effects of saving energy, reducing emission and changing waste into valuable are achieved; the method for preparing the industrial salt from the pickling waste liquid by using the waste heat realizes the recycling of the energy of the waste heat and the hot water, and the utilization rate of the waste heat reaches 60 to 80 percent. The cooling of high-temperature cooling water and waste heat water generated by the treatment of the pickling waste liquid can flow through a closed pipeline in a circulating way, the growth of microorganisms and the formation of scale are avoided due to the waste heat temperature, and the phenomenon that the traditional open type galvanized cooling water is cooled, and external dust particles, acid mist and the like enter the cooling water to pollute the cooling water is also avoided.

4. The method for preparing the industrial salt from the pickling waste liquid by utilizing the waste heat has the advantages that the used waste heat brine evaporating system is simple in equipment and reliable in operation and running, the problems that a multi-effect evaporator is easy to damage and old and needs to be maintained frequently like using electric energy or gas for heat supply are solved, and the maintenance cost of the brine evaporating equipment is saved.

[ description of the drawings ]

FIG. 1 is a process flow diagram of a method for preparing industrial salt from a spent pickle liquor by using waste heat according to the present invention;

FIG. 2 is a schematic diagram of the equipment and apparatus used in the method for preparing industrial salt from waste pickle liquor by using waste heat.

FIG. 2 labels:

1. an interlayer alkali preparation kettle; 2. a water pump; 3. an interlayer oxidation precipitation kettle; 4. an interlayer salt water evaporation tank; 5. an interlayer strong brine crystallization tank; 6. a pure water or circulating waste heat water inlet; 7. an outlet of the interlayer alkali-blending kettle residual hot water; 8. an inlet for residual hot water of the interlayer alkali preparation kettle; 9. an outlet for residual hot water of the interlayer oxidation precipitation kettle; 10. an inlet for the waste heat water of alkali preparation and oxidation precipitation; 11. a residual heat water outlet; 12. hot galvanizing high-temperature cooling water inlet; 13. a strong brine conveying pipeline; 14. a circulating waste heat cooling water outlet (returning to a hot galvanizing cooling water pool); 15. the interlayer circulates residual heat water.

[ detailed description ] embodiments

The following examples are provided to further illustrate the embodiments of the present invention.

The equipment and devices used in the examples are shown in fig. 2.

Example 1:

method for preparing industrial salt from pickling waste liquid by using waste heat, in particular to pickling waste liquid 5m generated in steel hot galvanizing day³The method for preparing the industrial salt by utilizing the waste heat specifically comprises the following steps:

1) adding 300kg of pure water into the interlayer alkali preparation kettle, adding 250kg of caustic soda flakes, and stirring to prepare 45.6 mass percent alkali liquor; heating circulating residual hot water in the interlayer by using alkali solution heat, leading out the circulating residual hot water, and pumping the heated circulating residual hot water into the interlayer of the oxidation precipitation kettle;

2) pumping pickling waste liquid into an interlayer oxidation precipitation kettle, adding an oxidant under the condition that the pH value of the pickling waste liquid is less than or equal to 1, and oxidizing and removing organic matters in the pickling waste liquid to obtain a first mixed liquid only containing metal cations such as hydrochloric acid, chloride ions, iron, zinc and the like;

3) adding the alkali liquor with the concentration of 45.6% prepared in the step 1) into the first mixed solution in the interlayer oxidation precipitation kettle, adjusting the pH value of the solution to be more than 8.0, converting metal cations such as iron, zinc and the like in the first mixed solution into insoluble metal hydroxides, precipitating from the solution, performing filter pressing to obtain a filtrate which is a second mixed solution, raising the temperature of water in an interlayer to be more than 80 ℃ by reaction heat released in the acid-base neutralization reaction process, and leading out interlayer hot water into an interlayer of an interlayer salt water evaporation tank for recycling;

4) and (3) passing the second mixed solution with higher conductivity through a catcher filled with amphoteric polymer resin, so that sodium ions, chloride ions and other ions in the mixed solution are caught by the catcher, and the conductivity of the water discharged by the catcher is reduced. When the conductivity of the solution from the catcher is similar to that of the second mixed solution, indicating that the ion catcher is in a saturated catching state, selectively backwashing the amphoteric polymer resin for 3 times by using pure water to obtain a backwashing solution as a third mixed solution;

5) conveying the third mixed solution to an interlayer salt water evaporation pool by a pump, and evaporating under the circulating heating of residual heat water to obtain a fourth mixed solution;

6) introducing the fourth mixed solution into an interlayer strong brine crystallization tank, and further evaporating and concentrating to separate out salt crystals; after crystals with certain thickness are separated out from the bottom of the crystallization tank, collecting salt by using a mechanical scraper and shoveling out the salt to obtain an industrial salt product;

7) inspecting and packaging to obtain a secondary standard of the sun-cured industrial salt with the quality meeting the industrial salt standard (GB/T5462-2015);

the interlayer alkali-blending kettle in the step 1) is a cylindrical alkali-blending kettle with mechanical stirring slurry, and the diameter and the height of the inner container and the outer cylinder are 5m according to the daily treatment of the waste pickling liquid³To determine; the prepared sodium hydroxide solution with the alkali liquor mass fraction of 45.6 percent has the dissolution heat of about 271.7X10 when the caustic soda flakes are dissolved in water³kJ, raising the temperature of water in the interlayer to over 55 ℃ by using the heat of dissolution, and conveying residual hot water circularly flowing in the interlayer to an interlayer oxidation precipitation kettle by using a pump;

the oxidant in the step 2) is hydrogen peroxide with the mass fraction of 18%, the mass ratio of the hydrogen peroxide to organic matters in the pickling waste liquid is 2.5:1, the dosing position is the bottom of the inner container tank, 4 nozzles are arranged in a delta shape, and the flow rate of the dosing liquid is controlled to be 10 mL/min; the cylindrical interlayer oxidation precipitation kettle is made of 316 stainless steel, wherein the diameter and the height of the inner container are phi 120cmX200cm, and the width of the interlayer is 10 cm;

the alkali liquor in the step 3) andthe mass ratio of the waste pickle liquor is 1.1:1, and the conductivity of the obtained second mixed liquor is>20000 mus/cm. The exothermic quantity of the neutralization reaction of the caustic soda flakes and the hydrochloric acid is about 1119.2X10³kJ, neutralizing heat to heat interlayer residual heat water in an interlayer alkali preparation kettle to be more than 80 ℃;

the third mixed solution in the step 4) is a sodium chloride solution with the mass fraction of about 15%;

the fourth mixed solution in the step 5) is concentrated brine obtained by evaporating water by taking waste hot water as a heat source, and the mass fraction of sodium chloride is 25%;

step 6), when the average thickness of the crystallized salt reaches 1.5cm, the salt is shoveled out in time so as to avoid influencing the heat transfer of hot water through a stainless steel inner container to the strong brine of the interlayer strong brine crystallizing pond;

step 1) a method for manufacturing an interlayer alkali-mixing kettle: phi 120cmX120cm, the inner container is made of 316 stainless steel, the wall thickness of the steel plate is 0.5mm, the outer cylinder is made of engineering plastic (resistant to 120 ℃ and 200 ℃) and the interlayer thickness is 8 cm. An interlayer waste heat water inlet pipe of the interlayer alkali-blending kettle is arranged at a position 15cm downwards from the top layer of the outer cylinder, and an interlayer waste heat water outlet pipe of the interlayer alkali-blending kettle is arranged at a position 10cm away from the bottom end of the outer cylinder;

step 2) a method for manufacturing the interlayer oxidation precipitation kettle: phi 120cmX160cm, wherein the inner container and the outer cylinder are both made of 316 stainless steel, the wall thickness of the steel plate is 0.6mm, the thickness of the interlayer is 4-8cm, a waste hot water inlet pipe of the interlayer oxidation precipitation kettle is arranged at a position 20cm below the top layer of the outer cylinder, and a waste hot water outlet pipe of the interlayer oxidation precipitation kettle is arranged at a position 5cm away from the bottom end of the outer cylinder;

step 5) the manufacturing method of the interlayer salt water evaporation tank comprises the following steps: 12.0mX3.5mX0.3m, the inner container is made of 304 stainless steel, the thickness of the steel plate is 0.6mm, the outer cylinder is made of carbon steel, the thickness of the carbon steel is 8mm, and the thickness of the interlayer is 14 cm;

step 6) manufacturing method of interlayer strong brine crystallization tank: 6.0mX10.0mX0.3m, the inner container is made of 304 stainless steel materials, the thickness of the steel plate is 0.6mm, the outer cylinder is made of carbon steel materials, the thickness of the carbon steel is 8mm, and the thickness of the interlayer is 8 cm.

Example 2:

method for preparing industrial salt from pickling waste liquor by using waste heat, wherein the pickling waste liquor is generated by 8m per day of hot galvanizing of steel³The method for preparing the industrial salt by utilizing the waste heat comprises the following steps:

1) adding 450kg of pure water into the interlayer alkali preparation kettle, adding 350kg of caustic soda flakes, and stirring to prepare 43.8% alkali liquor; heating interlayer waste heat water in an interlayer alkali preparation kettle by using alkali dissolution heat, leading out the water and pumping the water to an interlayer of an interlayer oxidation precipitation kettle;

2) pumping pickling waste liquid into an interlayer oxidation precipitation kettle, adding an oxidant under the condition that the pH value of the pickling waste liquid is less than or equal to 1, and oxidizing and removing organic matters in the pickling waste liquid to obtain a first mixed liquid only containing metal cations such as hydrochloric acid, chloride ions, iron, zinc and the like;

3) adding 43.8% alkali liquor prepared in the step 1) into the first mixed solution in the interlayer oxidation precipitation kettle, adjusting the pH value of the solution to 7.8-8.3, converting metal cations such as iron, zinc and the like in the first mixed solution into insoluble metal hydroxides, precipitating from the solution, performing filter pressing to obtain a filtrate as a second mixed solution, heating the water in the interlayer to 75-85 ℃ by reaction heat released in the acid-base neutralization reaction process, and leading hot water in the interlayer to an interlayer of an interlayer salt water evaporation tank for recycling;

4) passing the second mixed solution with higher conductivity through a catcher filled with amphoteric polymer resin, allowing the catcher to catch sodium ions, chloride ions and other ions in the mixed solution, reducing the conductivity of water discharged from the catcher, indicating that the ion catcher is in a saturated catching state when the conductivity of the solution discharged from the catcher is similar to that of the second mixed solution, and performing selective back washing on the amphoteric polymer resin for 3-4 times by using pure water to obtain a back washing solution as a third mixed solution;

5) conveying the third mixed solution to an interlayer salt water evaporation pool by a pump, and evaporating under the circulating heating of residual heat water to obtain a fourth mixed solution;

6) introducing the fourth mixed solution into an interlayer strong brine crystallization tank, and further evaporating and concentrating to separate out salt crystals; after crystals with certain thickness are separated out from the bottom of the crystallization tank, collecting salt by using a mechanical scraper and shoveling out the salt to obtain an industrial salt product;

7) inspecting and packaging to obtain a secondary standard of the sun-cured industrial salt with the quality meeting the industrial salt standard (GB/T5462-2015);

the interlayer alkali-blending kettle in the step 1) is a cylindrical alkali-blending kettle with mechanical stirring slurry, and the diameter and the height of the inner container and the outer cylinder are 8m according to the daily treatment of the pickling waste liquid amount³The prepared sodium hydroxide solution with the alkali liquor mass fraction of 43.8 percent is determined, and the dissolving heat of the caustic soda flakes after being dissolved in water is about 380.4X10³kJ, raising the temperature of water in the interlayer to over 60 ℃ by using the heat of dissolution, and conveying residual heat water circularly flowing in the interlayer to an oxidation precipitation kettle by using a pump;

the oxidant in the step 2) is hydrogen peroxide with the mass fraction of 20%, the mass ratio of the hydrogen peroxide to organic matters in the pickling waste liquid is 2.0:1, the dosing position is the bottom of the inner container tank, 5 nozzles are arranged in a delta shape, and the flow rate of the dosing liquid is controlled to be 15 mL/min; the cylindrical interlayer oxidation precipitation kettle is made of 316 stainless steel, the diameter and the height of the inner container are phi 140cmX240cm, and the width of the interlayer is 15 cm;

the mass ratio of the alkali liquor to the waste pickle liquor in the step 3) is 1.2:1, and the conductivity of the obtained second mixed liquor is>20000 mus/cm, the exothermic quantity of neutralization reaction of the caustic soda flakes and hydrochloric acid is about 1566.8X10³kJ, neutralizing heat to heat residual hot water in an interlayer from the interlayer alkali preparation kettle to more than 85 ℃;

the third mixed solution in the step 4) is a sodium chloride solution with the mass fraction of 17%;

the fourth mixed solution in the step 5) is concentrated brine obtained by evaporating water by taking waste hot water as a heat source, and the mass fraction of sodium chloride is 24%;

6) when the average thickness of the crystallized salt reaches 1.0cm, the salt is shoveled out in time so as to avoid influencing the heat transfer of hot water to strong brine of a crystallization tank through a stainless steel inner container;

step 1) a method for manufacturing an interlayer alkali-mixing kettle: the inner container phi 140cmX160cm is made of 316 stainless steel, the wall thickness of a steel plate is 0.5mm, the outer cylinder is made of engineering plastic (resistant to temperature of 120 ℃ and 200 ℃), the thickness of an interlayer is 8cm, an interlayer residual hot water inlet pipe in the interlayer alkali distribution kettle is arranged at a position 15cm below the top layer of the outer cylinder, and an interlayer residual hot water outlet pipe in the interlayer alkali distribution kettle is arranged at a position 10cm away from the bottom end of the outer cylinder;

step 2) a method for manufacturing the interlayer oxidation precipitation kettle: the inner container phi 120cmX160cm, the inner container and the outer cylinder are both made of 316 stainless steel, the wall thickness of a steel plate is 0.6mm, the thickness of an interlayer is 8cm, an interlayer oxidation precipitation kettle residual hot water inlet pipe is arranged at a position 20cm below the top layer of the outer cylinder, and an interlayer oxidation precipitation kettle residual hot water outlet pipe is arranged at a position 5cm away from the bottom end of the outer cylinder;

step 5) the manufacturing method of the interlayer salt water evaporation tank comprises the following steps: 14.0mX4.5 mX0.3m, the inner container is made of 304 stainless steel, the thickness of the steel plate is 0.6mm, the outer cylinder is made of carbon steel, the thickness of the carbon steel is 10mm, and the thickness of the interlayer is 15 cm;

the invention relates to a method for manufacturing an interlayer strong brine crystallization tank in step 6), which comprises the following steps: 7.0mX12.0mX0.3m, the inner container is made of 304 stainless steel materials, the thickness of the steel plate is 0.6mm, the outer cylinder is made of carbon steel materials, the thickness of the carbon steel is 10mm, and the thickness of the interlayer is 10 cm.

Example 3:

a method for preparing industrial salt from pickling waste liquid by using waste heat is to generate 3m pickling waste liquid in a steel hot galvanizing day³The method for preparing the industrial salt by utilizing the waste heat comprises the following steps:

1) adding 250kg of pure water into the interlayer alkali preparation kettle, adding 150kg of caustic soda flakes, and stirring to prepare 37.5% alkali liquor; the alkali solution heat heats the interlayer residual heat water in the interlayer alkali preparation kettle and leads the water out to be pumped into the interlayer of the interlayer oxidation precipitation kettle;

2) pumping pickling waste liquid into an interlayer oxidation precipitation kettle, adding an oxidant under the condition that the pH value of the pickling waste liquid is less than or equal to 1, and oxidizing and removing organic matters in the pickling waste liquid to obtain a first mixed liquid only containing metal cations such as hydrochloric acid, chloride ions, iron, zinc and the like;

3) adding the alkali liquor with the concentration of 37.5% prepared in the step 1) into the first mixed solution in the interlayer oxidation precipitation kettle, adjusting the pH value of the solution to 8.0, converting metal cations such as iron, zinc and the like in the first mixed solution into insoluble metal hydroxides, precipitating the insoluble metal hydroxides from the solution, performing filter pressing to obtain a filtrate as a second mixed solution, raising the temperature of water in the interlayer of the interlayer oxidation precipitation kettle to over 75 ℃ by reaction heat released in the acid-base neutralization reaction process, and leading out residual hot water in the interlayer of the interlayer oxidation precipitation kettle to the interlayer of an interlayer salt water evaporation tank for recycling;

4) passing the second mixed solution with higher conductivity through a catcher filled with amphoteric polymer resin, allowing the catcher to catch sodium ions, chloride ions and other ions in the mixed solution, reducing the conductivity of water discharged from the catcher, indicating that the ion catcher is in a saturated catching state when the conductivity of the solution discharged from the catcher is similar to that of the second mixed solution, and performing selective back washing on the amphoteric polymer resin for 3-4 times by using pure water to obtain a back washing solution as a third mixed solution;

5) conveying the third mixed solution to an interlayer salt water evaporation pool by a pump, and evaporating under the circulating heating of residual heat water to obtain a fourth mixed solution;

6) introducing the fourth mixed solution into an interlayer strong brine crystallization tank, and further evaporating and concentrating to separate out salt crystals; after crystals with certain thickness are separated out from the bottom of the crystallization tank, collecting salt by using a mechanical scraper and shoveling out the salt to obtain an industrial salt product;

7) inspecting and packaging to obtain a secondary standard of the sun-cured industrial salt with the quality meeting the industrial salt standard (GB/T5462-2015);

the interlayer alkali-blending kettle in the step 1) is a cylindrical alkali-blending kettle with mechanical stirring slurry, and the diameter and the height of the inner container and the outer cylinder are 3m according to the daily treatment of the pickling waste liquid amount³To decide. The prepared sodium hydroxide solution with 37.5 percent of alkali liquor mass fraction has the dissolution heat of 163.0X10 after dissolving the flaky alkali in water³kJ, raising the temperature of water in the interlayer to over 55 ℃ by using the heat of dissolution, and conveying the interlayer residual heat water in the interlayer of the interlayer alkali kettle into an interlayer oxidation precipitation kettle by using a pump;

the oxidant in the step 2) is hydrogen peroxide with the mass fraction of 18%, the mass ratio of the hydrogen peroxide to organic matters in the pickling waste liquid is 2.0:1, the dosing position is the bottom of the inner container tank, 3 nozzles are arranged in a delta shape, and the flow rate of the dosing liquid is controlled to be 5 mL/min; the cylindrical interlayer oxidation precipitation kettle is made of 316 stainless steel, the diameter and the height of the inner container are phi 100cmX180cm, and the width of the interlayer is 8 cm;

the mass ratio of the alkali liquor to the waste pickle liquor in the step 3) is 1.2:1, and the conductivity of the obtained second mixed liquor is>20000 mus/cm. The caustic soda flakes are generated with hydrochloric acidThe exotherm of the neutralization reaction is 671.5X10³kJ, neutralizing heat to heat residual hot water in an interlayer from the interlayer alkali preparation kettle to more than 85 ℃;

the third mixed solution in the step 4) is a sodium chloride solution with the mass fraction of 16%;

the fourth mixed solution in the step 5) is concentrated brine obtained by evaporating water by taking waste hot water as a heat source, and the mass fraction of sodium chloride is 24%;

step 6), when the average thickness of the crystallized salt reaches 1.2cm, the salt is timely shoveled out so as to avoid influencing the heat transfer of hot water through a stainless steel inner container to the strong brine filled in the interlayer strong brine crystallization tank;

step 1) a method for manufacturing an interlayer alkali-mixing kettle: the inner container phi 100cmX110cm is made of 316 stainless steel, the wall thickness of a steel plate is 0.4mm, the outer barrel is made of engineering plastic (resistant to 120 ℃ and 200 ℃) and the interlayer thickness is 6 cm. An interlayer residual heat water inlet pipe in the interlayer alkali-blending kettle is arranged at a position 15cm downwards from the top layer of the outer cylinder, and an interlayer residual heat water outlet pipe in the interlayer alkali-blending kettle is arranged at a position 15cm away from the bottom end of the outer cylinder;

step 2) a method for manufacturing the interlayer oxidation precipitation kettle: the inner container phi 110cmX150cm, the inner container and the outer cylinder are both made of 316 stainless steel materials, the wall thickness of a steel plate is 0.5mm, the thickness of an interlayer is 6cm, an interlayer oxidation precipitation kettle residual hot water inlet pipe is arranged at a position 15cm below the top layer of the outer cylinder, and an interlayer oxidation precipitation kettle residual hot water outlet pipe is arranged at a position 10cm away from the bottom end of the outer cylinder;

step 5) the manufacturing method of the interlayer salt water evaporation tank comprises the following steps: 10.0mX3.5mX0.3m, wherein the inner container is made of 304 stainless steel, the thickness of the steel plate is 0.5mm, the outer cylinder is made of carbon steel, the thickness of the carbon steel is 6mm, and the thickness of the interlayer is 10 cm;

step 6) manufacturing method of interlayer strong brine crystallization tank: 5.0mX8.0mX0.3m, the inner container is made of 304 stainless steel materials, the thickness of the steel plate is 0.5mm, the outer cylinder is made of carbon steel materials, the thickness of the carbon steel is 6mm, and the thickness of the interlayer is 8 cm.

Comparative example 1:

the difference from example 1 is: removing a waste heat circulating water heating system, changing into a solar salt drying mode, completely exposing a saline water evaporation tank and a saline water crystallization tank under sunlight, introducing a third mixed solution into the saline water evaporation tank, and evaporating under natural light irradiation; concentrating to obtain a fourth mixed solution, introducing into a strong brine crystallizing pond, and evaporating under natural light irradiation to crystallize the salt. The rest is the same as example 1.

Comparative example 2

The difference from example 1 is: the waste heat circulating water heating system is changed into an electric energy circulating water heating system, circulating water is heated by electric energy, and brine is evaporated, and the rest is the same as that in the embodiment 1.

And (3) effect comparison:

comparative analysis of the evaporation effect of process-derived brine generated by treating spent pickle liquor according to the above examples and comparative examples shows the results in table 1 below.

TABLE 1 Effect of different heating regimes on Evaporation of Pickling effluent process-derived brine

And (4) analyzing results:

1. as can be seen from the data of examples 1-3 in Table 1, the method for preparing industrial salt from pickling waste liquid by using waste heat, the treatment process and the hot galvanizing cooling process generate waste heat water to circularly heat and evaporate the process-derived brine, so that the effects of no extra energy consumption and high evaporation efficiency are achieved.

2. From the data of comparative example 1, it can be seen that when sunlight is used as a heating source for salt exposure, and the sunshine is sufficient in the test period, the efficiency is only 12.5% of the waste heat in comparison with example 1 in terms of time, and the yield is only 25% of the waste heat in terms of crystallization salt deposition, so that the treatment of the pickling waste liquid cannot be synchronized with the hot galvanizing production, and the requirement of continuous production cannot be met.

3. From the data of comparative example 2, in order to obtain the same effect as that of example 1 by using electric energy instead of waste heat to heat the derived brine by the evaporation process, 500kW · h of electricity is consumed daily, and 0.7 yuan of electricity per degree is consumed daily, which is a considerable cost, so that the operation cost is high and the feasibility is low due to the heating evaporation by using the electric energy.

In conclusion, the method for preparing the industrial salt from the pickling waste liquid by using the waste heat, disclosed by the invention, has the advantages that the waste heat circulating water is used for heating the evaporation process to obtain the derivative brine, the extraction process of the soluble salt in the pickling waste liquid is not influenced by weather conditions, the operation cost is low, and the energy is saved and the emission is reduced; the waste heat evaporation process of the method for preparing the industrial salt from the pickling waste liquid by using the waste heat can not be changed at will, and cannot be replaced if the method has the advantages of energy conservation and efficiency. The invention relates to a method for preparing industrial salt from pickling waste liquid by using waste heat, which really realizes zero emission, and is characterized in that soluble process derivative salt (the main component is sodium chloride) generated in the treatment process of the pickling waste liquid is crystallized and purified, a member washed by steel acid is immersed into a zinc liquid pool at the temperature of 435 +/-1 ℃ for hot galvanizing, a plated part is taken out of a pot and is cooled by water, the waste heat (the water temperature is 65-75 ℃) of direct cooling water, and circulating waste heat (the water temperature is 70-90 ℃) is heated and evaporated by using the dissolution heat generated by a sheet alkali-mixed solution, the neutralization heat generated by the neutralization reaction of alkali and the pickling waste liquid, and the like, so that the process derivative salt is concentrated, and the industrial salt is finally crystallized and separated out, and can be used as an industrial resource.

The above description is intended to describe in detail the preferred embodiments of the present invention, but the embodiments are not intended to limit the scope of the claims of the present invention, and all equivalent changes and modifications made within the technical spirit of the present invention should fall within the scope of the claims of the present invention.