CN104909507A - Contaminated acid concentrating and recycling method - Google Patents

Abstract

The invention discloses a method for concentrating and recycling polluted acid. The steps are as follows: adding polluted acid solution and vulcanizing agent solution with a dosage ratio of 1L: (10-30) g into a negative pressure reaction kettle, and the condition is 60-70°C. The reaction was carried out for 25~40min, and the reacted material was filtered by the filter press, and the filtrate was processed in the next step; the filtrate and vulcanizing agent solution with a dosage ratio of 1L: (20~48)g were added to the next negative pressure reaction kettle, React at room temperature for 80-100 minutes, then precipitate with a thickener and filter with a filter press. The obtained dirty acid filtrate is treated with a power wave scrubber to remove a large amount of F ^- and Cl ^- ions, and an industrial product with a concentration of 50-60% is obtained. sulfuric acid. The present invention combines two-stage vulcanization with evaporation and concentration to treat polluted acid. The two-stage vulcanization effectively removes heavy metals and arsenic through the control of time and temperature, and realizes the comprehensive recovery and utilization of sulfur and metal elements, with low cost and high economic benefits. .

Description

A method for concentrating and reusing polluted acid

technical field

The invention belongs to the field of metal smelting acid waste acid treatment, and in particular relates to a method for concentrating and recycling waste acid.

Background technique

In the non-ferrous metal smelting process, a large amount of dirty acid wastewater produced by the acid production process usually contains heavy metal ions such as As ³⁺ , As ⁵⁺ , Cu ²⁺ , Pb ²⁺ , Zn ²⁺ and F ^— , Cl ^— . The acid concentration is high and the heavy metal concentration is high. During the treatment process, the valuable metals are transferred to the waste residue, which is difficult to recycle. At the same time, a large amount of hazardous waste is generated, which is easy to cause serious secondary pollution.

At present, most smelting enterprises adopt sulfide-lime iron salt method, lime-iron salt method to treat dirty acid, sulfide to remove impurities, and lime milk neutralization method. These processes will consume a large amount of lime resources and produce a large amount of gypsum slag, causing serious damage to the environment. pollution, waste of resources, and high production costs; now there is a dirty acid treatment process for sulfuration and impurity removal, but the removal efficiency of the toxic metal arsenic in the dirty acid is low, and the environmental protection requirements are not met; and sulfuration and impurities are rarely combined with The comprehensive treatment of acid recovery has low economic benefits.

Contents of the invention

The purpose of the present invention is to provide a production method for concentrated reuse of polluted acid, which realizes the comprehensive recycling of polluted acid resources, the effective separation of heavy metals and arsenic in polluted acid, and achieves the goals of energy saving, emission reduction and zero discharge. Reduced production costs.

The present invention is achieved through the following technical solutions

A method for concentrating and recycling polluted acid, comprising the following steps:

Step (1): The first vulcanization: Add the dirty acid solution and vulcanizing agent solution with a dosage ratio of 1L: (10~30) g to a negative pressure reactor with a pressure of -250~-350Pa and mix evenly. Under the condition of 60~70℃, react for 25~40min; when the temperature is lower than 70℃, a small amount of H ₂ S gas is generated in the airtight container, and a small amount of hydrogen sulfide gas passes through the induced draft fan and the negative pressure is -900~-1000Pa The pressure is sucked into the matching lye washing tower, and the sodium sulfide solution obtained after washing can be used to prepare the vulcanizing agent through the control of the pH value; the reacted materials in the negative pressure reactor are transported to the pressure filter pump Filtration by the filter, the filtered residue sulfide is returned to the batching system for recycling; the filtrate enters the next negative pressure reactor for the second vulcanization;

During the first vulcanization process, the temperature is 60~70°C, at this temperature, too much H ₂ S will not escape, ensuring the effective progress of sulfide precipitation; at the same time, this temperature is conducive to the formation of heavy metal ion sulfide precipitation , is also conducive to the reaction of heavy metal ions and As ₂ S ₃ in the solution, so it is not conducive to the formation of arsenic sulfide precipitation; the reaction time is shorter, and it is also not conducive to the formation of arsenic sulfide precipitation; the precipitation rate of heavy metal ions in this process It reaches 99.2%, while the precipitation rate of arsenic is only 3~4.5%. The main reactions are as follows:

Na ₂ S + H ₂ SO ₄ = Na ₂ SO ₄ + H ₂ S

H ₂ S = 2H ⁺⁺ S ^2-

Na ₂ S = Na ⁺⁺ S ^2-

Cu ²⁺ + S ^2- = CuS

Pb ²⁺ + S ^2- = PbS

Zn ²⁺ + S ^2- = ZnS

Step (2): Second vulcanization: add the filtrate and vulcanizing agent solution obtained in step (1) with a dosage ratio of 1L: (20~48) g to a reaction kettle with a negative pressure of -450~-600Pa Mix evenly, and stop the reaction at room temperature for 80~100min. During this process, a small amount of H ₂ S gas is produced, and the hydrogen sulfide gas is sucked into the supporting lye washing by the induced draft fan at a negative pressure of -900~-1000Pa. In the tower, after the reacted materials in the negative pressure reactor are fully precipitated by the thickener, the ore slurry at the bottom is discharged from the bottom flow port of the thickener, and is transported to the filter press for filtration through a filter press pump to obtain arsenic sulfide residue, which is processed professionally. Arsenic extraction treatment; the dirty acid filtrate obtained after filtration is sent to the dirty acid concentration system through pipelines.

The reaction process is carried out at room temperature, and the reaction time is longer, which is conducive to the formation of arsenic sulfide precipitation; and can remove a small amount of other heavy metal ions remaining in the first sulfidation process; after the second sulfidation treatment, the arsenic in the polluted acid The removal rate reaches more than 99.5%; the main reactions in this process are as follows:

Na ₂ S + H ₂ SO ₄ = Na ₂ SO ₄ + H ₂ S

H ₂ S = 2H ⁺⁺ S ^2-

Na ₂ S = Na ⁺⁺ S ^2-

As ³⁺ + S ^2- = As ₂ S ₃

Step (3): The dirty acid filtrate obtained in step (2) is transported to the top of the power wave scrubber through the transfer pump, and sprayed downward from the top of the tower; the waste heat generated in the production system converts the air into hot air and enters the power The bottom of the wave scrubber is in reverse contact with the dirty acid filtrate from top to bottom, and the dirty acid filtrate is concentrated by high-temperature adiabatic evaporation to increase the acid concentration. At the same time, a large amount of F and Cl ions are taken away by the steam, and F and Cl The tail gas of the ions is discharged from the outlet pipe at the top of the power wave scrubber and passed into the matching lye scrubber to form salt for recycling. The obtained industrial sulfuric acid with a concentration of 50%~60% enters the acid storage tank. After concentrated treatment of dirty acid, the removal rate of F and Cl ions can reach more than 80%.

The method for concentrating and recycling dirty acid described above depends on the metal smelting process and raw materials, and the dirty acid components produced by the acid making system are also different. The dirty acid components in the present invention are mainly: H ₂ SO ₄ : 20000~30000mg/ L, As: 800~1500mg/L, Cu: 600~800mg/L, Zn: 300~600mg/L, Pb: 100~400mg/L, F: 500~1500mg/L, Cl: 500~1500mg/L.

In the method for concentrating and recycling polluted acid, the vulcanizing agent described in step (1) and step (2) is sodium sulfide, and the mass percentage of sodium sulfide solution is 10-15%;

In the method for concentrating and recycling dirty acid, the filter residue in step (1) mainly includes: copper sulfide, lead sulfide, and zinc sulfide.

In the method for concentrating and recycling dirty acid, the filter residue in step (2) is mainly arsenic sulfide.

In the method for concentrating and recycling dirty acid, the temperature of the hot air in step (3) is 200-280° C.; the rate of introduction of the hot air is 0.5-1.2 m/s.

Compared with the prior art, the present invention has the following positive effects

(1) The present invention uses the combination of two-stage vulcanization and sewage acid concentration to treat polluted acid wastewater, realizes the comprehensive recycling of sulfur resources, has the characteristics of improving the utilization rate of sulfur resources, environmental protection and energy saving; realizes the recovery of valuable metal elements Comprehensive recycling and resource utilization reduce pollutant discharge and raw material consumption, and reduce production costs.

(2) The process of the present invention has a wide range of applications. It can be used as raw materials for all waste water with F ^— , Cl ^— and As ³⁺ ion concentrations less than 10g/L, such as the wet purification of various sulfide ore smelting flue gases The dirty acid produced in the process, and the acid sewage produced in the process of anode slime treatment in the electrolysis workshop, etc.

(3) The neutralization process of "sulfurized lime milk neutralization method" will produce a large amount of gypsum slag, which not only takes up space but also causes secondary pollution to soil and water. It is difficult and expensive to landfill these gypsum slags ; In the treatment method of the present invention, the sulfur resources in the polluted acid are recovered in the form of industrial sulfuric acid, which improves the utilization rate of sulfur, avoids producing a large amount of gypsum slag, and eliminates the environmental protection pressure of the production and operation of enterprises.

(4) The invention uses the hot air generated by the waste heat of the production system to concentrate the polluted acid, and recovers the sulfur resources in the polluted acid in the form of industrial sulfuric acid by "making waste into waste", thereby improving the utilization rate of sulfur.

(5) This application adopts two vulcanization methods, through the control of time and temperature, the first vulcanization effectively removes the heavy metal ions in the polluted acid solution, and the obtained metal sulfides are returned to the raw material system as raw materials for smelting; the second Subsulfurization effectively removes the arsenic in the polluted acid solution, and the arsenic sulfide is subjected to professional arsenic refining treatment. Therefore, when the impurity removal treatment is carried out on the polluted acid, the highly toxic arsenic is effectively removed and separated, and the metals in the polluted acid are better recovered and utilized, which improves the economic benefits. The present invention not only effectively removes the F and Cl ions in the solution after two vulcanizations in the high-temperature concentration process, but also absorbs the F and Cl to form salts through the corresponding lye absorption tower, which is recycled and utilized, and the removal effect is good. High economic benefit.

(6) The treatment method provided by the present invention has low cost and significant economic benefits: Taking the copper smelting industry as an example, according to statistics, about 0.3-0.7m3 ^of polluted acid is produced per ton of copper, and the traditional neutralization method is used to treat ^1m3 of polluted acid. The average cost of acid is about 150 yuan (excluding the cost of lime slag landfill), and the cost of treating ^1m3 of dirty acid with the treatment method of the present invention can be reduced by about 50 yuan compared with the original process.

specific embodiment

In order to deepen the understanding of the present invention, the present invention will be further described below in conjunction with examples, which are only used to explain the present invention, and do not constitute a limitation to the protection scope of the present invention.

Example 1

A method for concentrating and recycling polluted acid, comprising the following steps:

Step (1): The first vulcanization: Add the dirty acid solution and sodium sulfide solution with a dosage ratio of 1L:25g into a negative pressure reactor with a pressure of -350Pa and mix evenly, react at 60°C for 40min, and the reaction stops The material in the final negative pressure reactor is transported to the filter press for filtration through the filter press pump, and the filtered filter residue is transported to the batching system for recycling, and the filtrate is transported to the next reactor for the second vulcanization treatment. A small amount of H ₂ S gas generated in this process is sucked into the matching lye washing tower by the induced draft fan at a negative pressure of -950~-1000Pa.

Step (2): The second vulcanization: Add the filtrate and sodium sulfide solution obtained in the step (1) with a dosage ratio of 1L:44g to a negative pressure reactor with a negative pressure of -600Pa, and react at room temperature for 80min. After stopping, the material in the negative pressure reactor is fully precipitated by the thickener, and the slurry at the bottom is discharged from the bottom flow port of the thickener, and transported to the filter press through the filter pump. After filtering, the filter residue is mainly arsenic sulfide, which is sent to a professional The manufacturer conducts arsenic extraction treatment; the dirty acid filtrate and the supernatant discharged from the ring groove at the top of the thickener are transported to the dirty acid concentration system through pipelines. A small amount of H ₂ S gas is generated during this process, which is sucked into the supporting lye washing tower by the induced draft fan at a negative pressure of -900~-950Pa.

Step (3): The dirty acid filtrate obtained in step (2) is transported to the top of the power wave scrubber through the dirty acid delivery pump, and sprayed downward from the top of the tower; the waste heat generated in the production system converts the air into hot air, The temperature of the hot air is 200°C, and it enters the bottom of the dynamic wave scrubber, and the velocity of the hot air is 1.2m/s. The hot air is fully in reverse contact with the dirty acid filtrate from the bottom of the tower to perform high-temperature adiabatic evaporation and concentration on the dirty acid filtrate. While increasing the acid concentration, a large amount of F and Cl ions are taken away by the steam, and F and Cl ions are taken away from the The outlet pipe at the top of the power wave scrubber is discharged into the matching lye scrubber to form salt for recycling. The obtained industrial sulfuric acid with a concentration of 50-60% enters the acid storage tank.

In the method for concentrating and recycling dirty acid, the dirty acid components in step (1) are mainly: H ₂ SO ₄ : 30000mg/L, As: 1500mg/L, Cu: 800mg/L, Zn: 600mg/L , Pb: 400mg/L, F: 1500mg/L, Cl: 1500mg/L.

In the method for concentrating and recycling dirty acid, the mass percentage of sodium sulfide is 10%.

In the method for concentrating and recycling dirty acid, the filter residue in step (1) mainly includes: copper sulfide, lead sulfide, and zinc sulfide.

In the method for concentrating and recycling dirty acid, the filter residue in step (2) is mainly composed of arsenic sulfide.

Example 2

A method for concentrating and recycling polluted acid, comprising the following steps:

Step (1): The first vulcanization: Add the dirty acid solution and sodium sulfide solution with a dosage ratio of 1L:10.5g into a negative pressure reactor with a pressure of -250Pa and mix evenly, react at 70°C for 25min, and react After the stop, the material in the negative pressure reactor is transported to the filter press for filtration through the filter press pump, and the filtered filter residue is transported to the batching system for recycling, and the filtrate is transported to the next reactor for the second vulcanization treatment. A small amount of H ₂ S gas produced in this process is sucked into the supporting lye washing tower by the induced draft fan at a pressure of -950~-1000Pa.

Step (2): Second vulcanization: Add the filtrate and sodium sulfide solution obtained in step (1) with a dosage ratio of 1L:29g into a negative pressure reactor with a negative pressure of -450Pa, and react at room temperature for 100min. After stopping, the material in the negative pressure reactor is fully precipitated by the thickener, and the slurry at the bottom is discharged from the bottom flow port of the thickener, and transported to the filter press through the filter pump. After filtering, the filter residue is mainly arsenic sulfide, which is sent to a professional The manufacturer conducts arsenic extraction treatment; the dirty acid filtrate and the supernatant discharged from the ring groove at the top of the thickener are transported to the dirty acid concentration system through pipelines. A small amount of H ₂ S gas is generated during this process, which is sucked into the supporting lye washing tower by the induced draft fan at a negative pressure of -900~-950Pa.

Step (3): The dirty acid filtrate obtained in step (2) is transported to the top of the power wave scrubber through the dirty acid delivery pump, and sprayed downward from the top of the tower; the waste heat generated in the production system converts the air into hot air, The temperature of the hot air is 280°C, and it enters the bottom of the dynamic wave scrubber, and the velocity of the hot air is 0.5m/s. The hot air is fully in reverse contact with the dirty acid filtrate from the bottom of the tower to perform high-temperature adiabatic evaporation and concentration on the dirty acid filtrate. While increasing the acid concentration, a large amount of F and Cl ions are taken away by the steam, and the amount of F and Cl ions is taken away. The tail gas is discharged from the outlet pipe at the top of the power wave scrubber and passed into the matching lye scrubber to form salt for recycling. The obtained industrial sulfuric acid with a concentration of 50-60% enters the acid storage tank.

In the method for concentrating and recycling dirty acid, the dirty acid components in step (1) are mainly: H ₂ SO ₄ : 20000mg/L, As: 800mg/L, Cu: 600mg/L, Zn: 300mg/L , Pb: 100mg/L, F: 500mg/L, Cl: 500mg/L.

In the method for concentrating and recycling dirty acid, the mass percentage of sodium sulfide is 15%.

In the method for concentrating and recycling dirty acid, the filter residue in step (1) mainly includes: copper sulfide, lead sulfide, and zinc sulfide.

In the method for concentrating and recycling dirty acid, the filter residue in step (2) is mainly composed of arsenic sulfide.

Example 3

A method for concentrating and recycling polluted acid, comprising the following steps:

Step (1): The first vulcanization: add the dirty acid solution and sodium sulfide solution with a dosage ratio of 1L:17g into a negative pressure reactor with a pressure of -300Pa and mix evenly, react at 65°C for 32min, and the reaction stops The material in the final negative pressure reactor is transported to the filter press for filtration through the filter press pump, and the filtered filter residue is transported to the batching system for recycling, and the filtrate is transported to the next reactor for the second vulcanization treatment. A small amount of H ₂ S gas produced in this process is sucked into the supporting lye washing tower by the induced draft fan at a pressure of -950~-1000Pa.

Step (2): Second vulcanization: Add the filtrate and sodium sulfide solution obtained in step (1) with a dosage ratio of 1L:29g into a negative pressure reactor with a negative pressure of -520Pa, and react at room temperature for 90min. After stopping, the material in the negative pressure reactor is fully precipitated by the thickener, and the slurry at the bottom is discharged from the bottom flow port of the thickener, and transported to the filter press through the filter pump. After filtering, the filter residue is mainly arsenic sulfide, which is sent to a professional The manufacturer conducts arsenic extraction treatment; the dirty acid filtrate and the supernatant discharged from the ring groove at the top of the thickener are transported to the dirty acid concentration system through pipelines. A small amount of H ₂ S gas is generated during this process, which is sucked into the supporting lye washing tower by the induced draft fan at a negative pressure of -900~-950Pa.

Step (3): The dirty acid filtrate obtained in step (2) is transported to the top of the power wave scrubber through the dirty acid delivery pump, and sprayed downward from the top of the tower; the waste heat generated in the production system converts the air into hot air, The temperature of the hot air is 240°C, and it enters the bottom of the dynamic wave scrubber with a velocity of 0.8m/s. The hot air is fully in reverse contact with the dirty acid filtrate from the bottom of the tower to perform high-temperature adiabatic evaporation and concentration on the dirty acid filtrate. While increasing the acid concentration, a large amount of F and Cl ions are taken away by the steam, and the amount of F and Cl ions is taken away. The tail gas is discharged from the outlet pipe at the top of the power wave scrubber and passed into the matching lye scrubber to form salt for recycling. The obtained industrial sulfuric acid with a concentration of 50-60% enters the acid storage tank. the

In the method for concentrating and recycling dirty acid, the dirty acid components in step (1) are mainly: H ₂ SO ₄ : 25000mg/L, As: 1150mg/L, Cu: 700mg/L, Zn: 450mg/L , Pb: 250mg/L, F: 1000mg/L, Cl: 1000mg/L.

In the method for concentrating and recycling dirty acid, the mass percentage of sodium sulfide is 12%.

In the method for concentrating and recycling dirty acid, the filter residue in step (1) mainly includes: copper sulfide, lead sulfide, and zinc sulfide.

In the method for concentrating and recycling dirty acid, the filter residue in step (2) is mainly composed of arsenic sulfide.

Example 4

A method for concentrating and recycling polluted acid, comprising the following steps:

Step (1): The first vulcanization: add the dirty acid solution and sodium sulfide solution with a dosage ratio of 1L:16.5g into a negative pressure reactor with a pressure of -320Pa and mix evenly, react at 62°C for 36min, and react After the stop, the material in the negative pressure reactor is transported to the filter press for filtration through the filter press pump, and the filtered filter residue is transported to the batching system for recycling, and the filtrate is transported to the next reactor for the second vulcanization treatment. A small amount of H ₂ S gas produced in this process is sucked into the supporting lye washing tower by the induced draft fan at a pressure of -950~-1000Pa.

Step (2): Second vulcanization: Add the filtrate and sodium sulfide solution obtained in step (1) with a dosage ratio of 1L:31.5g into a negative pressure reactor with a negative pressure of -560Pa, and react at room temperature for 85min. After the reaction is stopped, the material in the negative pressure reactor is fully precipitated by the thickener, and the slurry at the bottom is discharged from the bottom flow port of the thickener, and is transported to the filter press through the filter press pump. After filtering, the filter residue is mainly arsenic sulfide, which is sent to Professional manufacturers carry out arsenic extraction treatment; the dirty acid filtrate and the supernatant discharged from the ring groove at the top of the thickener are transported to the dirty acid concentration system through pipelines. A small amount of H ₂ S gas is generated during this process, which is sucked into the supporting lye washing tower by the induced draft fan at a negative pressure of -900~-950Pa.

Step (3): The dirty acid filtrate obtained in step (2) is transported to the top of the power wave scrubber through the dirty acid delivery pump, and sprayed downward from the top of the tower; the waste heat generated in the production system converts the air into hot air, The temperature of the hot air is 220°C, and it enters the bottom of the dynamic wave scrubber, and the velocity of the hot air is 1.0m/s. The hot air is fully in reverse contact with the dirty acid filtrate from the bottom of the tower to perform high-temperature adiabatic evaporation and concentration on the dirty acid filtrate. While increasing the acid concentration, a large amount of F and Cl ions are taken away by the steam, and the amount of F and Cl ions is taken away. The tail gas is discharged from the outlet pipe at the top of the power wave scrubber and passed into the matching lye scrubber to form salt for recycling. The obtained industrial sulfuric acid with a concentration of 50-60% enters the acid storage tank. the

In the method for concentrating and recycling dirty acid, the dirty acid components in step (1) are mainly: H ₂ SO ₄ : 27500mg/L, As: 1320mg/L, Cu: 750mg/L, Zn: 520mg/L , Pb: 320mg/L, F: 1250mg/L, Cl: 1250mg/L.

In the method for concentrating and recycling dirty acid, the mass percentage of sodium sulfide is 13%.

In the method for concentrating and recycling dirty acid, the filter residue in step (1) mainly includes: copper sulfide, lead sulfide, and zinc sulfide.

In the method for concentrating and recycling dirty acid, the filter residue in step (2) is mainly composed of arsenic sulfide.

Example 5

A method for concentrating and recycling polluted acid, comprising the following steps:

Step (1): The first vulcanization: Add the dirty acid solution and sodium sulfide solution with a dosage ratio of 1L:12g into a negative pressure reactor with a pressure of -280Pa and mix evenly, react at 68°C for 30min, and the reaction stops The material in the final negative pressure reactor is transported to the filter press for filtration through the filter press pump, and the filtered filter residue is transported to the batching system for recycling, and the filtrate is transported to the next reactor for the second vulcanization treatment. A small amount of H ₂ S gas produced in this process is sucked into the supporting lye washing tower by the induced draft fan at a pressure of -950~-1000Pa.

Step (2): Second vulcanization: add the filtrate and sodium sulfide solution obtained in step (1) with a dosage ratio of 1L:20.5g into a negative pressure reactor with a negative pressure of -480Pa, and react at room temperature for 95min. After the reaction is stopped, the material in the negative pressure reactor is fully precipitated by the thickener, and the slurry at the bottom is discharged from the bottom flow port of the thickener, and is transported to the filter press through the filter press pump. After filtering, the filter residue is mainly arsenic sulfide, which is sent to Professional manufacturers carry out arsenic extraction treatment; the dirty acid filtrate and the supernatant discharged from the ring groove at the top of the thickener are transported to the dirty acid concentration system through pipelines. A small amount of H ₂ S gas is generated during this process, which is sucked into the supporting lye washing tower by the induced draft fan at a negative pressure of -900~-950Pa.

Step (3): The dirty acid filtrate obtained in step (2) is transported to the top of the power wave scrubber through the dirty acid delivery pump, and sprayed downward from the top of the tower; the waste heat generated in the production system converts the air into hot air, The temperature of the hot air is 260°C, and it enters the bottom of the dynamic wave scrubber with a velocity of 0.7m/s. The hot air is fully in reverse contact with the dirty acid filtrate from the bottom of the tower, and the high-temperature adiabatic evaporation and concentration of the dirty acid filtrate is carried out. While increasing the acid concentration, a large amount of F and Cl ions are taken away by the steam, and the amount of F and Cl ions is taken away. The tail gas is discharged from the outlet pipe at the top of the power wave scrubber and passed into the matching lye scrubber to form salt for recycling. The obtained industrial sulfuric acid with a concentration of 50-60% enters the acid storage tank. the

In the method for concentrating and recycling dirty acid, the dirty acid components in step (1) are mainly: H ₂ SO ₄ : 22500mg/L, As: 980mg/L, Cu: 650mg/L, Zn: 380mg/L , Pb: 180mg/L, F: 750mg/L, Cl: 750mg/L.

In the method for concentrating and recycling dirty acid, the mass percentage of sodium sulfide is 15%.

In the method for concentrating and recycling dirty acid, the filter residue in step (1) mainly includes: copper sulfide, lead sulfide, and zinc sulfide.

In the method for concentrating and recycling dirty acid, the filter residue in step (2) is mainly composed of arsenic sulfide.

Example 6

A method for concentrating and recycling polluted acid, comprising the following steps:

Step (1): The first vulcanization: Add the acid solution and sodium sulfide solution with a dosage ratio of 1L:15g into a negative pressure reactor with a pressure of -290Pa and mix evenly, react at 67°C for 30min, after the reaction stops The material in the negative pressure reactor is transported to the filter press for filtration through the filter press pump, and the filtered residue is transported to the batching system for recycling, and the filtrate is transported to the next reactor for the second vulcanization treatment. A small amount of H ₂ S gas produced in this process is sucked into the supporting lye washing tower by the induced draft fan at a pressure of -950~-1000Pa.

Step (2): Second vulcanization: Add the filtrate and sodium sulfide solution obtained in step (1) with a dosage ratio of 1L:22.5g into a negative pressure reactor with a negative pressure of -500Pa, and react at room temperature for 93min. After the reaction is stopped, the material in the negative pressure reactor is fully precipitated by the thickener, and the slurry at the bottom is discharged from the bottom flow port of the thickener, and is transported to the filter press through the filter press pump. After filtering, the filter residue is mainly arsenic sulfide, which is sent to Professional manufacturers carry out arsenic extraction treatment; the dirty acid filtrate and the supernatant discharged from the ring groove at the top of the thickener are transported to the dirty acid concentration system through pipelines. A small amount of H ₂ S gas is generated during this process, which is sucked into the supporting lye washing tower by the induced draft fan at a negative pressure of -900~-950Pa.

Step (3): The dirty acid filtrate obtained in step (2) is transported to the top of the power wave scrubber through the dirty acid delivery pump, and sprayed downward from the top of the tower; the waste heat generated in the acid production system converts the air into hot air , the temperature of the hot air is 250°C, it enters the bottom of the dynamic wave scrubber, and the velocity of the hot air is 0.8m/s. The hot air is fully in reverse contact with the dirty acid filtrate from the bottom of the tower to perform high-temperature adiabatic evaporation and concentration on the dirty acid filtrate. While increasing the acid concentration, a large amount of F and Cl ions are taken away by the steam, and the amount of F and Cl ions is taken away. The tail gas is discharged from the outlet pipe at the top of the power wave scrubber and passed into the matching lye scrubber to form salt for recycling. The obtained industrial sulfuric acid with a concentration of 50-60% enters the acid storage tank. the

In the method for concentrating and recycling dirty acid, the dirty acid components in step (1) are mainly: H ₂ SO ₄ : 24000mg/L, As: 1000mg/L, Cu: 690mg/L, Zn: 530mg/L , Pb: 240mg/L, F: 900mg/L, Cl: 900mg/L.

In the method for concentrating and recycling dirty acid, the mass percentage of sodium sulfide is 14%.

In the method for concentrating and recycling dirty acid, the filter residue in step (1) mainly includes: copper sulfide, lead sulfide, and zinc sulfide.

In the method for concentrating and recycling dirty acid, the filter residue in step (2) is mainly composed of arsenic sulfide.

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Claims (8)

1. a method for concentrating and recycling polluted acid, is characterized in that, comprises the following steps: Step (1): Take the dirty acid solution and vulcanizing agent solution, add them to the negative pressure reactor, mix them evenly, and then react. After the reaction stops, the materials in the negative pressure reactor are sent to the filter press for filtration through the filter press pump, and the filter residue is recycled. , the filtrate enters the next step for processing; Step (2): Take the filtrate and vulcanizing agent solution obtained in step (1), add them to the negative pressure reactor, mix them evenly, and then react. The filter pump is transported to the filter press for filtration, the filter residue is recycled, and the dirty acid filtrate enters the next step of treatment; Step (3): The dirty acid filtrate obtained after the vulcanization treatment in step (2) is transported to the top of the power wave scrubber by the dirty acid delivery pump, and sprayed downward from the top of the tower; hot air enters the bottom of the power wave scrubber, and The dirty acid filtrate is in countercurrent contact, the hot air is concentrated by high-temperature adiabatic evaporation on the dirty acid filtrate, and the tail gas with F ^- and Cl ^- is discharged from the outlet pipe at the top of the power wave washing tower and passed into the alkali washing tower, where industrial sulfuric acid enters Acid storage tank. 2. The method for concentrating and recycling dirty acid according to claim 1, characterized in that: the dirty acid components in step (1) are: H ₂ SO ₄ : 20000~30000mg/L, As: 800~1500mg/L L, Cu: 600~800mg/L, Zn: 300~600mg/L, Pb: 100~400mg/L, F: 500~1500mg/L, Cl: 500~1500mg/L. 3. The method for concentrating and recycling polluted acid according to claim 1, characterized in that: the vulcanizing agent described in step (1) and step (2) is a sodium sulfide solution, and the mass percentage of the sodium sulfide solution is 10~15%. 4. The method for concentrating and recycling polluted acid according to claim 1, characterized in that the ratio of the amount of polluted acid added to the vulcanizing agent solution in step (1) is 1L: (10~30) g. 5. The method for concentrating and recycling dirty acid according to claim 1, characterized in that: the reaction pressure in the negative pressure reactor described in step (1) is -250~-350Pa, and the reaction temperature is 60~70°C , The reaction time is 25~40min. 6. The method for concentrating and recycling polluted acid according to claim 1, characterized in that: the dosage ratio of the filtrate added to the negative pressure reactor described in step (2) and the vulcanizing agent solution is: 1L: (20 ~48) g. 7. The method for concentrating and recycling polluted acid according to claim 1, characterized in that: the reaction pressure in the reactor described in step (2) is -450~-600Pa, and the reaction takes 80~100min at room temperature. 8. The method for concentrating and recycling dirty acid according to claim 1, characterized in that: the temperature of the hot air in step (3) is 200-280°C, and the rate of introduction of the hot air is 0.5-1.2m/ s.