CN111892220A - Equipment and method for treating smelting flue gas waste acid - Google Patents

Equipment and method for treating smelting flue gas waste acid Download PDF

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CN111892220A
CN111892220A CN202010681526.6A CN202010681526A CN111892220A CN 111892220 A CN111892220 A CN 111892220A CN 202010681526 A CN202010681526 A CN 202010681526A CN 111892220 A CN111892220 A CN 111892220A
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tank
liquid
acid
gas
heavy metal
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李喜仁
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    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F9/00—Multistage treatment of water, waste water or sewage
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/34—Chemical or biological purification of waste gases
    • B01D53/46—Removing components of defined structure
    • B01D53/48—Sulfur compounds
    • B01D53/52—Hydrogen sulfide
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/34—Chemical or biological purification of waste gases
    • B01D53/74—General processes for purification of waste gases; Apparatus or devices specially adapted therefor
    • B01D53/77—Liquid phase processes
    • B01D53/78—Liquid phase processes with gas-liquid contact
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/02—Treatment of water, waste water, or sewage by heating
    • C02F1/04—Treatment of water, waste water, or sewage by heating by distillation or evaporation
    • C02F1/08—Thin film evaporation
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/42—Treatment of water, waste water, or sewage by ion-exchange
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/52—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2101/00—Nature of the contaminant
    • C02F2101/10—Inorganic compounds
    • C02F2101/101—Sulfur compounds
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2101/00—Nature of the contaminant
    • C02F2101/10—Inorganic compounds
    • C02F2101/103—Arsenic compounds
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2101/00—Nature of the contaminant
    • C02F2101/10—Inorganic compounds
    • C02F2101/12—Halogens or halogen-containing compounds
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2101/00—Nature of the contaminant
    • C02F2101/10—Inorganic compounds
    • C02F2101/12—Halogens or halogen-containing compounds
    • C02F2101/14—Fluorine or fluorine-containing compounds
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2101/00—Nature of the contaminant
    • C02F2101/10—Inorganic compounds
    • C02F2101/20—Heavy metals or heavy metal compounds
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2103/00—Nature of the water, waste water, sewage or sludge to be treated
    • C02F2103/18—Nature of the water, waste water, sewage or sludge to be treated from the purification of gaseous effluents
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2301/00—General aspects of water treatment
    • C02F2301/08—Multistage treatments, e.g. repetition of the same process step under different conditions

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  • Life Sciences & Earth Sciences (AREA)
  • Hydrology & Water Resources (AREA)
  • Engineering & Computer Science (AREA)
  • Environmental & Geological Engineering (AREA)
  • Water Supply & Treatment (AREA)
  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Removal Of Specific Substances (AREA)

Abstract

The invention provides equipment and a method for treating metallurgical off-gas waste acid, wherein the equipment comprises the following steps: the low bed acid retardation resin tank is provided with a first liquid discharge port for discharging elution acid liquid and a second liquid discharge port for discharging heavy metal waste liquid; the first sedimentation tank is provided with a first liquid inlet, an air outlet and a feed port for adding sulfide, and the first liquid inlet is connected with the second liquid outlet; the second sedimentation tank is provided with a second liquid inlet, an air inlet and a discharge port, the second liquid inlet is connected with the first liquid discharge port, and the air inlet is connected with the air exhaust port; and the falling film concentration device is connected to the discharge port. The invention solves the problem that the waste acid liquid generates a large amount of waste residues containing heavy metals and brings higher secondary pollution hidden trouble by adopting the traditional treatment method.

Description

Equipment and method for treating smelting flue gas waste acid
Technical Field
The invention relates to the technical field of waste acid and waste liquid treatment, in particular to equipment and a method for treating smelting smoke waste acid.
Background
A certain amount of waste acid liquid is generated in the acid making process by smelting flue gas. For the traditional treatment of the waste acid liquid, a method of adding lime and ferric salt is generally adopted, and in addition, a method of combining with sulfide precipitation is also adopted. Regardless of the mode, a large amount of lime or sulfide is consumed, and simultaneously, a large amount of waste residues containing heavy metals are generated, so that the hidden danger of secondary pollution is brought.
Disclosure of Invention
In order to overcome the defects in the prior art, the equipment and the method for treating the smelting flue gas waste acid are provided so as to solve the problem that the waste acid liquid generates a large amount of waste residues containing heavy metals and brings higher secondary pollution hidden trouble by adopting the traditional treatment method.
In order to realize the purpose, the equipment and the method for treating the smelting flue gas waste acid are provided, and the equipment and the method comprise the following steps:
carrying out acid retardation separation on heavy metal waste acid to obtain an elution acid solution and heavy metal waste liquid;
adding sulfide into the heavy metal waste liquid to generate heavy metal precipitate and hydrogen sulfide gas;
introducing the hydrogen sulfide gas into the eluting acid solution to generate heavy metal precipitates and obtain purified acid solution;
and the purified acid liquid is subjected to falling film concentration to obtain concentrated recovered acid liquid, and the heavy metal precipitate is roasted and smelted to recover heavy metals.
Further, the step of adding sulfide into the heavy metal waste liquid comprises:
adding a first sulfide into the heavy metal waste liquid and adjusting the pH value of the heavy metal waste liquid to 2 to generate a first precipitate;
and adding a second disulfide into the heavy metal waste liquid from which the first precipitate is removed, and adjusting the pH value of the heavy metal waste liquid to 7-8 to generate a second precipitate.
The invention provides equipment for treating metallurgical off-gas waste acid, which comprises:
the low bed acid retardation resin tank is provided with a first liquid discharge port for discharging elution acid liquid and a second liquid discharge port for discharging heavy metal waste liquid;
the first sedimentation tank is provided with a first liquid inlet, an air outlet and a feed port for adding sulfide, and the first liquid inlet is connected with the second liquid outlet;
the second sedimentation tank is provided with a second liquid inlet, an air inlet and a discharge port, the second liquid inlet is connected with the first liquid discharge port, and the air inlet is connected with the air exhaust port; and
and the falling film concentration device is connected to the discharge port.
Further, the diameter of the resin in the short bed acid retardation resin tank is 0.12 mm-0.2 mm, the height of the resin mass transfer area of the short bed acid retardation resin tank is 0.15 m-0.61 m, and the resin is filled in the short bed acid retardation resin tank.
Further, the first settling tank comprises:
the first tank body is provided with the first liquid inlet, the exhaust port, a feed port for feeding a first sulfide and a feed port for feeding a flocculating agent;
the first reaction tank is arranged in the first box body, and the first liquid inlet and the feed port are respectively communicated with the first reaction tank; and
the first flocculation tank is arranged in the first box body, the upper part of the first flocculation tank is communicated with the upper part of the first reaction tank, the agent feeding port is communicated with the first flocculation tank, and a sedimentation inclined plate is arranged in the first flocculation tank.
Further, the first settling tank further comprises:
the second reaction tank is arranged in the first tank body, the upper part of the second reaction tank is communicated with the upper part of the first flocculation tank, the first tank body is provided with a feed port for adding a second disulfide, and the feed port is communicated with the second reaction tank; and
the second flocculation tank is installed in the first tank body, the upper portion of the second flocculation tank is communicated with the upper portion of the second reaction tank, the first tank body is provided with a dosing port used for dosing a flocculating agent, the dosing port is communicated with the second flocculation tank, and a sedimentation inclined plate is installed in the second flocculation tank.
Further, the second settling tank comprises:
the second box body is provided with the second liquid inlet, the air inlet, the discharge port and a dosing port;
the second liquid inlet and the air inlet are respectively communicated with the second reaction tank;
the third flocculation tank is arranged in the second tank body, the upper part of the third flocculation tank is communicated with the upper part of the third reaction tank, the agent feeding port is communicated with the third flocculation tank, and a sedimentation inclined plate is arranged in the third flocculation tank; and
and the desulfurization tank is arranged in the second box body, the discharge port is communicated with the desulfurization tank, and the upper part of the desulfurization tank is communicated with the upper part of the third flocculation tank.
Further, the falling film concentration apparatus includes:
the top of the cylinder is provided with an overflow port and two jet ports, and the bottom of the cylinder is provided with an acid discharge port;
the falling film evaporation tube is arranged in the middle of the barrel body and is arranged along the axial direction of the barrel body, an impact space is formed between the upper end of the falling film evaporation tube and the top of the barrel body, and a concentrated solution collecting space is formed between the lower end of the falling film evaporation tube and the bottom of the barrel body;
and
the gas-liquid injection pipes are respectively arranged in the two injection holes, pipe orifices of the two gas-liquid injection pipes are oppositely arranged, the gas-liquid injection pipes are connected with the discharge port, and the gas-liquid injection pipes are connected with a gas inlet pipe for inputting hot gas flow.
Further, the gas-liquid injection pipe is a venturi pipe.
Further, the gas-liquid injection pipe is arranged along the radial direction of the cylinder.
The equipment and the method for treating the waste acid in the smelting flue gas have the advantages that the waste acid (waste acid) generated in the acid preparation from the smelting flue gas is recycled, the acid preparation yield from the flue gas is improved, and the main indexes meet the industrial sulfuric acid execution standard. Because most of the waste acid is recycled, the consumption of lime for waste acid treatment is greatly reduced, and the amount of generated waste residues is less than 20 percent of that of the traditional method. After the sulfide (sodium sulfide) reacts with the low-acidity heavy metal waste liquid, on one hand, the heavy metal of the heavy metal waste liquid is removed; on the other hand, the hydrogen sulfide gas generated by the reaction can be used for removing residual heavy metals in the eluting acid solution, so that the consumption of sulfide (sodium sulfide) is reduced. Heavy metal precipitates generated in the reaction are all metal sulfide precipitates, and can return to the front end for roasting smelting according to the characteristics of a smelting plant, so that the recovery of heavy metals is realized, and the economic benefit is improved.
Drawings
FIG. 1 is a process route diagram of the equipment and method for treating metallurgical off-gas acid according to the embodiment of the invention.
Fig. 2 is a schematic structural diagram of a first settling tank according to an embodiment of the present invention.
Fig. 3 is a schematic structural diagram of a second settling tank according to an embodiment of the present invention.
Fig. 4 is a schematic structural diagram of a falling film evaporator according to an embodiment of the present invention.
FIG. 5 is a schematic flow diagram of acid retardation according to an embodiment of the present invention.
Detailed Description
The embodiments of the present invention are described below with reference to specific embodiments, and other advantages and effects of the present invention will be easily understood by those skilled in the art from the disclosure of the present specification. The invention is capable of other and different embodiments and of being practiced or of being carried out in various ways, and its several details are capable of modification in various respects, all without departing from the spirit and scope of the present invention.
Fig. 1 is a schematic structural diagram of a device for treating smelting flue gas contaminated acid according to an embodiment of the invention, fig. 2 is a schematic structural diagram of a first settling tank according to an embodiment of the invention, fig. 3 is a schematic structural diagram of a second settling tank according to an embodiment of the invention, fig. 4 is a schematic structural diagram of a falling film evaporator according to an embodiment of the invention, and fig. 5 is a schematic flow diagram of acid retardation according to an embodiment of the invention. .
Referring to fig. 1 to 5, the invention provides a method for treating metallurgical off-gas acid, which comprises the following steps: the system comprises a low bed acid retardation resin tank 1, a first settling tank 2, a second settling tank 3 and a falling film concentration device 4.
The short bed acid retardation resin tank 1 has a first drain port for discharging the eluting acid solution c and a second drain port for discharging the heavy metal waste liquid b. The first settling tank 2 is provided with a first liquid inlet, an air outlet and a feeding port for feeding sulfide, and the first liquid inlet is connected with a second liquid outlet. In this example, the sulfide is sodium sulfide. The second settling tank 3 is provided with a second liquid inlet, an air inlet and a discharge port. The second liquid inlet is connected with the first liquid outlet, and the air inlet is connected with the air outlet. The falling film concentration device 4 is connected to a discharge port.
In a preferred embodiment, the diameter of the resin in the short bed acid retardation resin tank 1 is 0.12mm to 0.2 mm. The height of the resin mass transfer area of the short bed acid retardation resin tank 1 is 0.15 m-0.61 m. The short bed acid retardation resin tank 1 is filled with resin particles.
In conventional fixed bed processes, the exchange takes up only a small portion of the mass transfer zone. Therefore, most of the resin in the resin column is inactive. The short bed acid retardation resin tank reduces the height of an inactive area, and can more effectively utilize the remaining resin. More importantly, when the depth of the mass transfer area is reduced to 0.15-0.61 m, the reaction kinetics can be effectively increased.
The short bed technology of the short bed acid retardation resin tank uses resin particles of 80-120 meshes, the diameter of the resin particles is 0.12-0.2 mm, and the resin particles are much smaller than those in the traditional ion exchange system (about 20% of the particle diameter of the traditional resin particles). The resin particles reduce the particle size, so that the exchange dynamics is greatly improved. This allows operation at higher flow rates and reduces the length of the exchange zone. The exchange rate of the resin is inversely proportional to the square of the particle size of the resin. Thus, reducing the particle size by half can increase the exchange efficiency by about 400%. The higher flow rate thus significantly reduces the amount of resin required. The finer particle size also helps to provide a uniform distribution of the fluid, thus reducing the amount of flushing required.
Unlike conventional resin beds, the short bed acid retarded resin tank of the present invention is completely filled with resin particles without leaving any space. The full bed low bed acid retarded resin tank eliminates dilution problems and helps to maintain the concentration profile in the resin bed.
Referring to fig. 5, the low bed acid retardation resin tank of the present invention employs pure water f downstream elution mode, and realizes four-stage control using conductance values and time: a drainage stage, a high brine stage, an acid-top stage and an acid-recovering stage.
As a preferred embodiment, the first settling tank 2 comprises: a first tank 21, a first reaction tank 22 and a first flocculation tank 23.
Specifically, the first tank 21 is provided with a first liquid inlet, an air outlet, a feeding port for feeding the first sulfide, and a feeding port for feeding the flocculant. The first sulfide is sodium sulfide. The flocculant is Polyacrylamide (PAM).
The first reaction tank 22 is installed in the first casing 21. The first liquid inlet and the feeding port are respectively communicated with the first reaction tank 22. The first flocculation tank 23 is installed in the first tank 21, and is adjacent to the first reaction tank. The upper part of the first flocculation tank 23 is communicated with the upper part of the first reaction tank 22. The agent feeding port is communicated with the first flocculation tank 23. The first flocculation tank 23 is provided therein with a precipitation slant plate 5.
In this embodiment, the first settling tank 2 further includes a second reaction tank 24 and a second flocculation tank 25.
The second reaction tank 24 is installed in the first tank 21, and is adjacent to the first flocculation tank. The upper part of the second reaction tank 24 is communicated with the upper part of the first flocculation tank 23. The first box 21 is provided with a feeding port for feeding a second disulfide. The feeding port is communicated with the second reaction tank 24. The second sulfide is sodium sulfide.
The second flocculation tank 25 is installed in the first tank 21 and adjacent to the second reaction tank. The upper part of the second flocculation tank 25 is communicated with the upper part of the second reaction tank 24. The first box body 21 is provided with a feeding port for feeding a flocculating agent. The flocculating agent is polyacrylamide. The agent feeding port is communicated with the second flocculation tank 25. The second flocculation tank 25 is provided with a sedimentation inclined plate 5.
In the first box body, a reaction tank and a flocculation tank are used as units, the first reaction tank and the first flocculation tank are used for controlling the pH value of the heavy metal waste liquid to be about 2, arsenic sulfide is precipitated from the heavy metal waste liquid by utilizing sodium sulfide, and H is generated by the reaction2S gas; the second reaction tank and the second flocculation tank are used for controlling the pH value of the heavy metal waste liquid to be 7-8, and sodium sulfide is used for precipitating other metal sulfide precipitates in the heavy metal waste liquid. Other metal sulfide precipitates include copper sulfide, lead sulfide, zinc sulfide, cadmium sulfide, iron sulfide, and the like.
As a preferred embodiment, the second settling tank 3 comprises: a second tank 31, a third reaction tank 32, a third flocculation tank 33 and a desulfurization tank 34.
Specifically, the second tank 31 is provided with a second liquid inlet, an air inlet for introducing H2S gas, a discharge outlet, and a dosing port for dosing a flocculant. The third reaction tank 32 is installed in the second casing 31. The second liquid inlet and the air inlet are respectively communicated with the third reaction tank 32. The third flocculation tank 33 is installed in the second tank 31 and is adjacent to the third reaction tank 32. The upper part of the third flocculation tank 33 is communicated with the upper part of the third reaction tank 32. The agent feeding port is communicated with the third flocculation tank 33. The flocculant is the third reaction tank 32. The third flocculation tank 33 is provided with a sedimentation inclined plate 5. The desulfurization tank 34 is installed in the second tank 31, and is adjacent to the third flocculation tank. The discharge port is communicated with the desulfurization tank 34, and the upper part of the desulfurization tank 34 is communicated with the upper part of the third flocculation tank 33.
In a preferred embodiment, stirrers are installed in the first reaction tank, the first flocculation tank, the second reaction tank, the second flocculation tank, the third reaction tank, the third flocculation tank, and the desulfurization tank, respectively.
As a preferred embodiment, the falling film concentration apparatus 4 comprises: cylinder 41, falling film evaporation tube 42 and two gas-liquid injection tubes 43.
Specifically, the top of the cylinder 41 is provided with an overflow port and two injection ports, and the bottom of the cylinder 41 is provided with an acid discharge port for discharging concentrated recovered acid e.
The falling film evaporation tube 42 is installed in the middle of the cylinder 41. The falling film evaporation tube 42 is disposed along the axial direction of the cylinder 41. An impact space is formed between the upper end of the falling film evaporation tube 42 and the top of the cylinder 41, and a concentrated solution collecting space is formed between the lower end of the falling film evaporation tube 42 and the bottom of the cylinder 41.
The two gas-liquid injection pipes 43 are respectively installed in the two injection ports. The two gas-liquid injection pipes 43 are arranged oppositely. The gas-liquid injection pipe 43 is connected to the discharge port. The gas-liquid injection pipe 43 is connected to an intake pipe for inputting a hot gas flow.
In the present embodiment, the gas-liquid injection pipe 43 is a venturi pipe. The gas-liquid injection pipe 43 is provided in the radial direction of the cylinder 41.
The falling film concentration device is an impinging stream falling film concentrator. The cylinder body is made of corrosion-resistant and high-temperature-resistant materials,
the upper part of the cylinder is an impinging stream region (impinging space) comprising two radially mounted venturi tubes. Two gas-liquid mixed phases are introduced by using a Venturi tube, are oppositely arranged and impact on an impact flow area at a high speed to form impact flow.
The middle part of the cylinder body is a falling film evaporation tube area. The falling film evaporation tube is a combination of a plurality of falling film evaporation tubes made of graphite or quartz materials. The inner surface of the falling film evaporation tube is processed in a concave-convex mode to increase the surface area.
The lower part of the cylinder is a collection area (concentrated solution collection space) for concentrated recovered acid solution. Two hot air pipes which are arranged in the radial direction are arranged at the middle lower part of the cylinder body, and the hot air and the liquid film run in the reverse direction to enhance the heat transfer effect.
The falling film concentration device 4 also comprises peripheral auxiliary devices. The peripheral auxiliary device comprises a blower, an electric heater, a condenser, a heat exchanger, a tail gas absorption tank and an instrument. The meters include a thermometer, a flowmeter, a liquid level meter, a differential pressure meter and the like.
The invention provides a method for treating metallurgical off-gas waste acid, which comprises the following steps:
s1, separating heavy metal contaminated acid a by acid retardation to obtain an elution acid liquid c and a heavy metal waste liquid b.
Heavy metal contaminated acid a is subjected to acid retardation separation in a short bed acid retardation resin tank 1 to obtain an elution acid liquid c and heavy metal waste liquid b.
The elution acid liquid c and the heavy metal waste liquid b are discharged from a first liquid discharge port and a second liquid discharge port of the short bed acid retardation resin tank 1 respectively.
S2, adding sulfide into the heavy metal waste liquid b to generate heavy metal precipitates and hydrogen sulfide gas;
specifically, the step S2 includes:
s21: and adding a first sulfide into the heavy metal waste liquid b and adjusting the pH value of the heavy metal waste liquid b to be 2 so as to generate a first precipitate.
The heavy metal waste liquid b is discharged into the first reaction tank through the second liquid outlet and the first liquid inlet. Sodium sulfide is added into a first reaction tank containing heavy metal waste liquid b through a feeding port, the pH value of the heavy metal waste liquid is controlled to be about 2, the heavy metal waste liquid overflows into a first flocculation tank after reaction, and simultaneously generated H2The S gas is introduced into the third reaction tank of the second settling tank through the exhaust port. And (3) adding a flocculating agent into the first flocculating tank through the agent adding port, so that the first precipitate (arsenic sulfide) is precipitated on the inclined precipitation plate. The precipitated arsenic sulfide is discharged and collected, and can be used for roasting, smelting and collecting heavy metals.
S22: and adding a second disulfide into the heavy metal waste liquid b without the first precipitate and adjusting the pH value of the heavy metal waste liquid b to 7-8 to generate a second precipitate.
And other heavy metals are remained in the heavy metal waste liquid of the first flocculation tank, and the heavy metal waste liquid overflows into the second reaction tank. And adding sodium sulfide into the second reaction tank containing the heavy metal waste liquid through a feeding port, controlling the pH value of the heavy metal waste liquid to be about 7-8, and overflowing into the second flocculation tank after reaction. And (4) adding a flocculating agent into the second flocculation tank through the agent adding port, so that the second precipitate is precipitated on the precipitation inclined plate. And discharging the second precipitate, and collecting the second precipitate, wherein the second precipitate can be used for roasting, smelting and collecting heavy metals.
And S3, introducing hydrogen sulfide gas into the eluting acid liquid c to generate heavy metal precipitates and obtain purified acid liquid d.
The eluted acid liquid c is discharged to the third reaction tank of the second settling tank through the first liquid discharge port, and H generated in step S212And (4) introducing the S gas into a third reaction tank of a second settling tank through an exhaust port to generate heavy metal precipitate (arsenic sulfide) and obtain purified acid liquor d. And overflowing the reaction liquid to a third flocculation tank, adding a flocculating agent through a dosing port, and precipitating arsenic sulfide on a precipitation inclined plate. The precipitated eluting acid solution overflows into a desulfurization tank, and the absorption liquid in the desulfurization tank absorbs H in the eluting acid solution2And (5) obtaining purified acid liquid d from the S gas. The absorption liquid is sodium hydroxide solution. Further, the absorption liquid is a sodium hydroxide solution with the mass fraction of 30%
S4, the purified acid liquid d is subjected to falling film concentration to obtain concentrated recovered acid liquid e, and heavy metal precipitates are roasted and smelted to recover heavy metals.
The purified acid liquor is conveyed to the falling film concentration device 4 through a discharge port of the second settling tank for impact flow falling film concentration.
Specifically, the working process of the falling film concentration device 4 is as follows:
the purified acid liquid d from the discharge port of the second settling tank is preheated by a heat exchanger.
The air flow generated by the blast of the blower is preheated by the condenser and then heated by the electric heater to form hot air, and the hot air is introduced into the gas-liquid injection pipe.
The preheated purified acid liquid d and the hot air are sprayed into the impact space by the gas-liquid spraying pipe together. In the impact space, two gas-liquid injection pipes are opposite to each other, so that two gas-liquid mixed phases are subjected to violent collision and heat and mass transfer. Due to the difference of density and boiling point, hydrofluoric acid, hydrochloric acid and a part of water vapor in the purified acid liquid overflow from an overflow port at the top of the cylinder, and the small mixed sulfuric acid liquid particles with high density enter the falling film evaporation tube under the action of gravity, so that the hot air at the bottom of the cylinder provides a heat source for continuous evaporation.
And (3) removing most of fluorine and chlorine in the purified acid liquor by using a falling film concentration device, and simultaneously concentrating the dilute sulfuric acid to a certain extent to finally obtain concentrated recovered acid liquor.
A generated by acid preparation from smelting flue gas is a sulfuric acid system, the acid concentration of the sulfuric acid system is usually between 2% and 15%, and a certain amount of heavy metal ions and fluorine chloride anions exist at the same time. These ion concentrations range from a few milligrams per liter to a few grams per liter depending on the flue gas cleaning and dust collection effects.
The equipment and the method for treating the waste acid in the smelting flue gas realize resource recovery of the waste acid (waste acid) generated in the acid making from the smelting flue gas, improve the yield of the acid making from the flue gas, and meet the industrial sulfuric acid execution standard by main indexes. Because most of the waste acid is recycled, the consumption of lime for waste acid treatment is greatly reduced, and the amount of generated waste residues is less than 20 percent of that of the traditional method. After the sulfide (sodium sulfide) reacts with the low-acidity heavy metal waste liquid, on one hand, the heavy metal of the heavy metal waste liquid is removed; on the other hand, the hydrogen sulfide gas generated by the reaction can be used for removing residual heavy metals in the eluting acid solution, so that the consumption of sulfide (sodium sulfide) is reduced. Heavy metal precipitates generated in the reaction are all metal sulfide precipitates, and can return to the front end for roasting smelting according to the characteristics of a smelting plant, so that the recovery of heavy metals is realized, and the economic benefit is improved.
It should be noted that the structures, ratios, sizes, and the like shown in the drawings attached to the present specification are only used for matching the disclosure of the present specification, so as to be understood and read by those skilled in the art, and are not used to limit the conditions of the present invention, so that the present invention has no technical essence, and any structural modification, ratio relationship change, or size adjustment should still fall within the scope of the present invention without affecting the efficacy and the achievable purpose of the present invention. In addition, the terms "upper", "lower", "left", "right", "middle" and "one" used in the present specification are for clarity of description, and are not intended to limit the scope of the present invention, and the relative relationship between the terms and the terms is not to be construed as a scope of the present invention.
While the present invention has been described in detail and with reference to the embodiments thereof as illustrated in the accompanying drawings, it will be apparent to one skilled in the art that various changes and modifications can be made therein. Therefore, certain details of the embodiments are not to be interpreted as limiting, and the invention is to be defined by the scope of the appended claims.

Claims (10)

1. The method for treating the metallurgical off-gas acid is characterized by comprising the following steps:
carrying out acid retardation separation on heavy metal waste acid to obtain an elution acid solution and heavy metal waste liquid;
adding sulfide into the heavy metal waste liquid to generate heavy metal precipitate and hydrogen sulfide gas;
introducing the hydrogen sulfide gas into the eluting acid solution to generate heavy metal precipitates and obtain purified acid solution;
and the purified acid liquid is subjected to falling film concentration to obtain concentrated recovered acid liquid, and the heavy metal precipitate is roasted and smelted to recover heavy metals.
2. The method for treating the metallurgical off-gas acid according to claim 1, wherein the step of adding sulfide into the heavy metal waste liquid comprises the following steps:
adding a first sulfide into the heavy metal waste liquid and adjusting the pH value of the heavy metal waste liquid to 2 to generate a first precipitate;
and adding a second disulfide into the heavy metal waste liquid from which the first precipitate is removed, and adjusting the pH value of the heavy metal waste liquid to 7-8 to generate a second precipitate.
3. The equipment for treating the waste acid of the smelting flue gas is characterized by comprising the following components:
the low bed acid retardation resin tank is provided with a first liquid discharge port for discharging elution acid liquid and a second liquid discharge port for discharging heavy metal waste liquid;
the first sedimentation tank is provided with a first liquid inlet, an air outlet and a feed port for adding sulfide, and the first liquid inlet is connected with the second liquid outlet;
the second sedimentation tank is provided with a second liquid inlet, an air inlet and a discharge port, the second liquid inlet is connected with the first liquid discharge port, and the air inlet is connected with the air exhaust port; and
and the falling film concentration device is connected to the discharge port.
4. The apparatus for treating metallurgical off-gas waste acid according to claim 3, wherein the diameter of the resin in the short bed acid retardation resin tank is 0.12mm to 0.2mm, the height of the resin mass transfer zone of the short bed acid retardation resin tank is 0.15m to 0.61m, and the short bed acid retardation resin tank is filled with the resin.
5. The apparatus for treating metallurgical off-gas acidity of claim 3, wherein the first settling tank comprises:
the first tank body is provided with the first liquid inlet, the exhaust port, a feed port for feeding a first sulfide and a feed port for feeding a flocculating agent;
the first reaction tank is arranged in the first box body, and the first liquid inlet and the feed port are respectively communicated with the first reaction tank; and
the first flocculation tank is arranged in the first box body, the upper part of the first flocculation tank is communicated with the upper part of the first reaction tank, the agent feeding port is communicated with the first flocculation tank, and a sedimentation inclined plate is arranged in the first flocculation tank.
6. The apparatus for treating metallurgical off-gas acids according to claim 5, wherein the first settling tank further comprises:
the second reaction tank is arranged in the first tank body, the upper part of the second reaction tank is communicated with the upper part of the first flocculation tank, the first tank body is provided with a feed port for adding a second disulfide, and the feed port is communicated with the second reaction tank; and
the second flocculation tank is installed in the first tank body, the upper portion of the second flocculation tank is communicated with the upper portion of the second reaction tank, the first tank body is provided with a dosing port used for dosing a flocculating agent, the dosing port is communicated with the second flocculation tank, and a sedimentation inclined plate is installed in the second flocculation tank.
7. The apparatus for treating metallurgical off-gas acids according to claim 3, wherein the second settling tank comprises:
the second box body is provided with the second liquid inlet, the air inlet, the discharge port and a dosing port;
the second liquid inlet and the air inlet are respectively communicated with the second reaction tank;
the third flocculation tank is arranged in the second tank body, the upper part of the third flocculation tank is communicated with the upper part of the third reaction tank, the agent feeding port is communicated with the third flocculation tank, and a sedimentation inclined plate is arranged in the third flocculation tank; and
and the desulfurization tank is arranged in the second box body, the discharge port is communicated with the desulfurization tank, and the upper part of the desulfurization tank is communicated with the upper part of the third flocculation tank.
8. The plant for treating metallurgical off-gas acid according to claim 3, wherein the falling film concentrating device comprises:
the top of the cylinder is provided with an overflow port and two jet ports, and the bottom of the cylinder is provided with an acid discharge port;
the falling film evaporation tube is arranged in the middle of the barrel body and is arranged along the axial direction of the barrel body, an impact space is formed between the upper end of the falling film evaporation tube and the top of the barrel body, and a concentrated solution collecting space is formed between the lower end of the falling film evaporation tube and the bottom of the barrel body; and
the gas-liquid injection pipes are respectively arranged in the two injection holes, pipe orifices of the two gas-liquid injection pipes are oppositely arranged, the gas-liquid injection pipes are connected with the discharge port, and the gas-liquid injection pipes are connected with a gas inlet pipe for inputting hot gas flow.
9. The apparatus for treating metallurgical off-gas acidity according to claim 8, wherein the gas-liquid injection pipe is a venturi pipe.
10. The apparatus for treating metallurgical off-gas acid according to claim 8, wherein the gas-liquid injection pipe is arranged along a radial direction of the cylinder.
CN202010681526.6A 2020-07-15 2020-07-15 Equipment and method for treating smelting flue gas waste acid Pending CN111892220A (en)

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Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH09887A (en) * 1996-06-17 1997-01-07 Tokuyama Corp Method for regenerating acid waste liquid
JP2000117270A (en) * 1998-10-09 2000-04-25 Nippon Steel Corp Treatment of metal-containing waste water and method for recovering valuable metal
CN102167422A (en) * 2011-01-21 2011-08-31 南京工业大学 Recovery process of industrial waste acid
CN103553248A (en) * 2013-10-23 2014-02-05 中南大学 Heavy metal waste acid and wastewater resource recycling method and device
CN104445095A (en) * 2014-12-18 2015-03-25 中南大学 Method for purifying smelting waste acid
CN105439356A (en) * 2015-12-28 2016-03-30 中南大学 Method and device for synchronously recycling sulfuric acid and fluorine and chlorine from polluted acid
CN107311345A (en) * 2017-07-28 2017-11-03 科海思（北京）科技有限公司 A kind of waste acidity recovery method and apparatus

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH09887A (en) * 1996-06-17 1997-01-07 Tokuyama Corp Method for regenerating acid waste liquid
JP2000117270A (en) * 1998-10-09 2000-04-25 Nippon Steel Corp Treatment of metal-containing waste water and method for recovering valuable metal
CN102167422A (en) * 2011-01-21 2011-08-31 南京工业大学 Recovery process of industrial waste acid
CN103553248A (en) * 2013-10-23 2014-02-05 中南大学 Heavy metal waste acid and wastewater resource recycling method and device
CN104445095A (en) * 2014-12-18 2015-03-25 中南大学 Method for purifying smelting waste acid
CN105439356A (en) * 2015-12-28 2016-03-30 中南大学 Method and device for synchronously recycling sulfuric acid and fluorine and chlorine from polluted acid
CN107311345A (en) * 2017-07-28 2017-11-03 科海思（北京）科技有限公司 A kind of waste acidity recovery method and apparatus

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Application publication date: 20201106