Self-circulation arsenic removal production line

Abstract

The utility model discloses a self-circulation arsenic removal production line, which can remove more than 99.7% of arsenic from high-concentration arsenic-containing wastewater through an arsenic removal unit, a precipitation unit and an MVR (mechanical vapor recompression) evaporation unit which are communicated in sequence and a circulating system which is finally formed and is communicated with the precipitation unit, and has the characteristics that arsenic removal sludge is stable and is difficult to dissolve out for the second time; meanwhile, the whole arsenic removal process is completed at the normal temperature, no arsenic volatilization pollutes the atmosphere, and finally obtained evaporated waste salt is common solid waste and can be widely applied to treatment of various kinds of complex industrial wastewater containing arsenic and heavy metal.

Description

TECHNICAL FIELD

[0001] The utility model relates to non ferrous metallurgy technical field, concretely is a kind of self-circulation arsenic removal production line. BACKGROUND

[0002] In the process of roasting arsenic-containing materials (such as arsenic-containing gold concentrate, copper concentrate, copper anode slime, etc.), some arsenic-containing and heavy metal pollutants are contained in the tail gas. The conventional wet arsenic removal technology is to contact the arsenic-containing solid particles with water or liquid, wet the surface of the particles, and make them adhere to the liquid, so as to achieve the purpose of removing the particles. The wet arsenic removal technology has the advantages of simple equipment structure, small investment and high efficiency, but it needs to consume a large amount of water, which causes the problem of arsenic-containing wastewater treatment.

[0003] If the arsenic-containing pollutants in the wastewater are not treated before being discharged, it will cause serious pollution to the surrounding water resources and soil resources. In addition, arsenic compounds are a kind of toxic substances, which can enter the human body through food, water, etc., and also cause harm to the human body. Therefore, the environmental protection department has strict standards for the arsenic content in the production wastewater discharged by the factory. At present, some enterprises use steam mechanical recompression technology MVR (Mechanical Vapor Recompression) to treat wastewater in the wastewater zero discharge process. This process needs to pretreat and concentrate the wastewater first, and then separate the salt from the wastewater by evaporation crystallization. Common arsenic-containing wastewater pretreatment technologies include precipitation method, ion exchange method, membrane separation method, biological method and adsorption method, etc.

[0004] It should be noted that the precipitation method is mainly used for the treatment of high-concentration arsenic-containing wastewater, and has the advantages of less investment, simple process and high treatment efficiency; the ion exchange method is mainly used for the treatment of low-concentration arsenic-containing wastewater, but the price of resin is high, and the one-time investment is large, which limits the practical application of this method; the membrane separation method has high requirements for equipment, membrane and operating conditions, and is generally used for the recovery of useful components in wastewater or the reuse of water; the biological method has no secondary pollution and low treatment cost, but the treatment time is long, and the treatment effect is greatly affected by environmental factors such as temperature, pH value and dissolved oxygen; the adsorption method has the advantages of simple operation, high treatment efficiency and low use cost, but the service life of the adsorption material is short and needs to be replaced regularly. So far, the precipitation method is still the most commonly used method for treating arsenic-containing wastewater in most enterprises.

[0005] The pre-treatment by precipitation can effectively reduce the concentration of arsenic in the wastewater, so as to meet the requirements of the evaporation salt operation. During the evaporation salt operation in the MVR evaporator, the water in the wastewater is continuously evaporated, so that the residual arsenic in the wastewater is concentrated and the concentration is increased. If the high-concentration arsenic-containing mother liquor continues to be subjected to the MVR evaporation salt operation, the arsenic in the solution will be doped in the evaporation salt product in the form of calcium arsenate and iron salt, thereby affecting the quality of the salt. In addition, the existence of the calcium arsenate and the iron salt will block the MVR evaporator, thereby increasing the operation load of the evaporator and reducing the evaporation salt efficiency. Therefore, it is necessary to pre-treat the high-concentration arsenic-containing mother liquor generated after the evaporation salt operation, so as to meet the requirements and then continue the evaporation salt treatment. Content of the utility model

[0006] Therefore, the utility model provides a kind of self-circulation dearsenification production line, to be able to effectively treat the arsenic-containing wastewater generated in industrial production.

[0007] To achieve the above object, the utility model provides the following technical scheme: a kind of self-circulation dearsenification production line, including the dearsenification unit, sedimentation unit and MVR evaporation unit that are sequentially communicated, wherein, still be provided with dosing unit, with the sedimentation unit communication;

[0008] The dearsenification unit is used to receive wastewater, control pH value under the action of the dosing unit, generate solid precipitate, and carry out solid-liquid separation, extract filtrate and input the sedimentation unit;

[0009] The sedimentation unit is used to receive filtrate output from the dearsenification unit, control pH value under the action of the dosing unit, generate solid precipitate, and carry out solid-liquid separation, extract filtrate and input the MVR evaporation unit;

[0010] The MVR evaporation unit is used to receive filtrate output from the sedimentation unit, sequentially carry out decalcification and evaporation salt treatment, obtain concentrated mother liquor, and then re-input the concentrated mother liquor into the dearsenification unit.

[0011] By using the above technical scheme, the dearsenification unit, the sedimentation unit and the MVR evaporation unit that are sequentially communicated are used, wherein, the dosing unit is further provided and communicated with the sedimentation unit, and finally a circulating system is formed, which can remove more than 99.7% of arsenic from high-concentration arsenic-containing wastewater, has the characteristics of stable dearsenification sludge, difficult secondary dissolution, low sludge output, etc., and the entire dearsenification process is completed at room temperature, without arsenic volatilization to pollute the atmosphere, and the final evaporation waste salt is a general solid waste, which can be widely applied to the treatment of various complex industrial wastewater containing arsenic and heavy metals.

[0012] Further, the dearsenification unit includes a water collecting pool, a dearsenification reactor and a first filter press that are sequentially communicated by pipelines.

[0013] Further, the precipitation unit comprises a first-stage precipitation tank and a second-stage precipitation tank which are sequentially communicated through pipelines, wherein the input end of the first-stage precipitation tank is communicated with the output end of the first filter press through a pipeline.

[0014] Further, the dosing unit comprises a lime milk dosing tank, a dearsenic agent dosing tank, a coagulant dosing tank, a flocculant dosing tank and a heavy metal capture agent dosing tank which are respectively communicated with the first-stage precipitation tank and / or the second-stage precipitation tank through pipelines, wherein the output end of the lime milk dosing tank is respectively communicated with the input ends of the first-stage precipitation tank and the second-stage precipitation tank through pipelines, the output end of the dearsenic agent dosing tank is communicated with the input end of the first-stage precipitation tank through a pipeline, the output ends of the coagulant dosing tank and the flocculant dosing tank are respectively communicated with the input ends of the first-stage precipitation tank and the second-stage precipitation tank through pipelines, and the output end of the heavy metal capture agent dosing tank is communicated with the input end of the second-stage precipitation tank through a pipeline.

[0015] Further, the first-stage precipitation tank and the second-stage precipitation tank are respectively communicated with a sludge tank through pipelines.

[0016] Further, the MVR evaporation unit comprises a decalcified raw water tank, a second filter press, an MVR evaporator and a circulation tank which are sequentially communicated through pipelines, wherein the output end of the circulation tank is communicated with the other input end of the arsenic removal reactor through a pipeline.

[0017] Further, the input ends of the first-stage precipitation tank and the second-stage precipitation tank are located above the output ends of the first-stage precipitation tank and the second-stage precipitation tank. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 It is a structural schematic view of the self-circulation arsenic removal production line.

[0019] In the figure: 1, a water collecting tank; 2, a lime milk dosing tank; 3, a dearsenic agent dosing tank; 4, an arsenic removal reactor; 5, a first filter press; 6, a first-stage precipitation tank; 7, a coagulant dosing tank; 8, a flocculant dosing tank; 9, a heavy metal capture agent dosing tank; 10, a second-stage precipitation tank; 11, a sludge tank; 12, a decalcified raw water tank; 13, a second filter press; 14, an MVR evaporator; 15, a circulation tank. DETAILED DESCRIPTION

[0020] In order to facilitate the understanding of the present application, the present application will be described more fully below with reference to the related drawings. The drawings show several embodiments of the present application. However, the present application can be realized in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present application more thorough and comprehensive.

[0021] It should be noted that when an element is referred to as being "on" another element, it can be directly on the other element or intervening elements can also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements can also be present. As used herein the terms "vertical", "horizontal", "left", "right" and similar terms are used for explanation purposes only.

[0022] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description herein is for describing particular embodiments only and is not intended to be limiting of the application. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0023] The embodiments will be described below according to the overall structure of the application.

[0024] A self-circulation arsenic removal production line, as shown in the figure, the self-circulation arsenic removal production line provided by the application comprises an arsenic removal unit, a sedimentation unit and an MVR evaporation unit which are sequentially communicated, wherein, a dosing unit is further arranged and communicated with the sedimentation unit; Figure 1 The arsenic removal unit is used for receiving wastewater, under the action of the dosing unit, controlling the pH value, generating solid precipitate, and performing solid-liquid separation, extracting the filtrate to input the sedimentation unit, specifically, the arsenic removal unit comprises a water collecting pool 1, an arsenic removal reactor 4 and a first filter press 5 which are sequentially communicated through pipelines, wherein, the high-concentration arsenic-containing wastewater is first stored in the water collecting pool 1, the water outlet of the water collecting pool 1 is sent to the arsenic removal reactor 4 to perform sufficient reaction, the lime milk and the arsenic removal agent are sequentially added in the arsenic removal reactor 4 through the dosing unit, after the solid precipitate is generated, the solid-liquid separation is performed through the first filter press 5, and the filtrate is punched into a primary sedimentation tank 6, in this embodiment, the arsenic removal agent is selected from one or more of ferrous sulfate, aluminum sulfate and polymeric ferric sulfate;

[0025]

[0026] ​The precipitation unit is used for receiving the filtrate from the output of the arsenic removal unit, generating solid precipitate under the action of the dosing unit, and performing solid-liquid separation to extract the filtrate and input the MVR evaporation unit. Specifically, the precipitation unit comprises a first-stage precipitation tank 6 and a second-stage precipitation tank 10 which are sequentially connected through pipelines. The input end of the first-stage precipitation tank 6 is connected with the output end of the first filter press 5 through a pipeline. In addition, the input ends of the first-stage precipitation tank 6 and the second-stage precipitation tank 10 are located above the output ends of the first-stage precipitation tank 6 and the second-stage precipitation tank 10. The first-stage precipitation tank 6 and the second-stage precipitation tank 10 are further connected with the sludge tank through pipelines. It should be noted that the dosing unit comprises a lime milk dosing tank 2, a dearsenification agent dosing tank 3, a coagulant dosing tank 7, a flocculant dosing tank 8 and a heavy metal capture agent tank 9 which are connected with the pipelines of the first-stage precipitation tank 6 and / or the second-stage precipitation tank 10. The output end of the lime milk dosing tank 2 is connected with the input ends of the first-stage precipitation tank 6 and the second-stage precipitation tank 10 through pipelines. The output end of the dearsenification agent dosing tank 3 is connected with the input end of the first-stage precipitation tank 6 through a pipeline. The output ends of the coagulant dosing tank 7 and the flocculant dosing tank 8 are connected with the input ends of the first-stage precipitation tank 6 and the second-stage precipitation tank 10 through pipelines. The output end of the heavy metal capture agent tank 9 is connected with the input end of the second-stage precipitation tank 10 through a pipeline. In this embodiment, the coagulant is an inorganic high polymer, and the inorganic high polymer is selected from one or more of polyaluminum chloride, polyferric chloride and polyaluminum ferric chloride. The flocculant is an organic high polymer, and the organic high polymer is selected from cationic polyacrylamide with an ionic degree of 30-50. The heavy metal capture agent is selected from one or more of xanthate and dithiocarbamate derivatives.

[0027] The MVR evaporation unit is used for receiving the filtrate from the output of the precipitation unit, performing decalcification and salt evaporation in sequence to obtain concentrated mother liquor, and then re-feeding the concentrated mother liquor into the arsenic removal unit. The decalcification process adopts any one of, but not limited to, a double-alkali method, a sodium carbonate method and a CO2 decalcification method. Specifically, the MVR evaporation unit comprises a decalcification raw water tank 12, a second filter press 13, an MVR evaporator 14 and a circulation tank 15 which are sequentially connected through pipelines. The output end of the circulation tank 15 is connected with the other input end of the arsenic removal reactor 4 through a pipeline.

[0028] In summary, the self-circulation arsenic removal production line disclosed by the utility model, through the arsenic removal unit, the sedimentation unit and the MVR evaporation unit which are communicated in sequence, wherein, the dosing unit is further arranged and communicated with the sedimentation unit, and finally forms a circulation system, which can remove more than 99.7% of arsenic from high-concentration arsenic-containing wastewater, has the characteristics of stable arsenic removal sludge, difficult secondary elution, low sludge output, etc., and the whole arsenic removal process is completed at normal temperature, without arsenic volatilization to pollute the atmosphere, and the final evaporated waste salt is general solid waste, which can be widely applied to the treatment of various complex industrial wastewater containing arsenic and heavy metals.

[0029] It should be noted that in the actual production process, the self-circulation arsenic removal production line is operated as follows, which is illustrated by a specific embodiment.

[0030] The high-concentration arsenic-containing wastewater first enters the water collecting pool for storage, and the initial concentration of arsenic in the wastewater is detected as 1547.0 mg / L. The effluent of the water collecting pool is punched into the arsenic removal reactor, and then lime milk and polyferric sulfate are sequentially added in the arsenic removal reactor through the dosing device for sufficient reaction; the pH value is controlled at 6-7 at normal temperature, the reaction time is controlled for 3-4 hours, and solid precipitate is generated; solid-liquid separation is performed by the first filter press, the filtrate is punched into the primary sedimentation tank, and the arsenic concentration of the filtrate is detected as 23.21 mg / L, at which time the arsenic removal rate is 98.5%. Then the low-concentration arsenic-containing wastewater is treated in the primary sedimentation tank, and lime milk, polyferric sulfate, polyaluminum chloride and polyacrylamide are added through the dosing device; the pH value is controlled at 8-9 at normal temperature, the reaction time is controlled for 3-4 hours, and sludge solid precipitate is generated; the sludge enters the sludge pool, and the supernatant is punched into the secondary sedimentation tank; the wastewater is treated in the secondary sedimentation tank: lime milk, polyaluminum chloride, polyacrylamide and heavy metal capture agent DTCR are added through the dosing device; the pH value is controlled at 8-9 at normal temperature, the reaction time is controlled for 3-4 hours, and solid precipitate sludge is generated; the sludge enters the sludge pool, and the supernatant effluent can enter the subsequent softening system for calcium removal treatment, wherein the arsenic concentration is detected as 4.47 mg / L, and the arsenic removal rate is 99.71%. Finally, the wastewater softening treatment process adopts the sodium carbonate method, and the water sample after calcium removal softening enters the MVR evaporator for salt evaporation. The concentrated mother liquor of the wastewater after MVR salt evaporation operation is difficult to treat due to the increase of arsenic concentration, and the mother liquor is pumped into the circulation pool and then enters the arsenic removal system with high-concentration arsenic-containing raw wastewater, and then is evaporated for salt again after meeting the requirements.

[0031] In the description of the specification, the description of the terms "one embodiment", "some embodiments", "an example", "a specific example", or "some examples" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the utility model. In the specification, the illustrative description of the above terms does not necessarily mean the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0032] The above-described embodiments only express several implementation manners of the utility model, the description is more specific and detailed, but it cannot be understood as the limitation of the utility model patent scope. It should be pointed out that for ordinary skilled in the art, without departing from the concept of the utility model, a number of modifications and improvements can be made, which belong to the protection scope of the utility model. Therefore, the protection scope of the utility model patent should be subject to the appended claims.

Claims

1. A self-circulation arsenic removal production line, characterized in that, The arsenic removal unit, the precipitation unit and the MVR evaporation unit are sequentially connected, and a dosing unit is arranged and communicated with the precipitation unit; The arsenic removal unit is used for receiving wastewater, controlling pH value under the action of the dosing unit, generating solid precipitate, and performing solid-liquid separation to extract filtrate and input the filtrate into the precipitation unit; The precipitation unit is used for receiving the filtrate output from the arsenic removal unit, controlling pH value under the action of the dosing unit, generating solid precipitate, and performing solid-liquid separation to extract filtrate and input the filtrate into the MVR evaporation unit; The MVR evaporation unit is used for receiving the filtrate output from the precipitation unit, sequentially performing decalcification and salt evaporation treatment to obtain concentrated mother liquor, and re-feeding the concentrated mother liquor into the arsenic removal unit.

2. The self-circulating arsenic removal production line according to claim 1, characterized in that, The arsenic removal unit comprises a water collecting pool, an arsenic removal reactor and a first filter press which are sequentially connected by pipelines.

3. The self-circulating arsenic removal production line according to claim 2, characterized in that, The precipitation unit comprises a first-stage precipitation pool and a second-stage precipitation pool which are sequentially connected by pipelines.

4. The self-circulation arsenic removal production line according to claim 3, characterized in that, The dosing unit comprises lime milk dosing tanks, arsenic removal agent dosing tanks, coagulant dosing tanks, flocculant dosing tanks and heavy metal capture agent dosing tanks which are respectively communicated with the first-stage precipitation pool and / or the second-stage precipitation pool by pipelines.

5. The self-circulating arsenic removal production line according to claim 4, characterized in that, The first-stage precipitation pool and the second-stage precipitation pool are respectively communicated with a sludge pool by pipelines.

6. The self-circulating arsenic removal production line according to claim 5, characterized in that, The MVR evaporation unit comprises a decalcification raw water pool, a second filter press, an MVR evaporator and a circulation pool which are sequentially connected by pipelines.

7. The self-circulating arsenic removal production line according to claim 4, characterized in that, The input ends of the first-stage precipitation pool and the second-stage precipitation pool are located above the output ends of the first-stage precipitation pool and the second-stage precipitation pool.

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