System for producing ferric trichloride water purifying agent by resource utilization of iron-containing waste hydrochloric acid and sludge

Abstract

The utility model discloses a system for producing a ferric trichloride water purifying agent by resource utilization of iron-containing waste hydrochloric acid and sludge. The system comprises a pretreatment module, a feeding buffer module, a preheating module, a triple-effect evaporation and concentration module, a vacuum module, a shaft seal water module, a cooling water circulation module and an instrument electric control module. According to the system, iron-containing waste hydrochloric acid and iron-containing sludge can be converted into the ferric trichloride water purifying agent, resource utilization of waste is achieved, the concept of environmental protection and resource recovery is met, the system directly obtains the liquid ferric trichloride water purifying agent through evaporation and concentration treatment, further evaporation and crystallization for salt production are not needed, the production process is simplified, and the production cost is reduced. Meanwhile, the product can be directly used as a water purifying agent, and water does not need to be added again; the system is provided with a pretreatment module which comprises the steps of dissolution acidification, impurity removal, blending acidification, oxidation synthesis and the like, impurities in waste acid and sludge can be effectively removed, and it is ensured that the quality of a final product is stable and controllable.

Description

TECHNICAL FIELD

[0001] The utility model relates to the resource utilization related technical field especially relates to the system of containing iron waste hydrochloric acid and sludge resource utilization production ferric trichloride water purifying agent. BACKGROUND

[0002] Steel processing enterprises use strong acid (hydrochloric acid or sulfuric acid) as cleaning agent to remove rust on the surface of metal, after pickling to a certain extent, the acid content in pickling solution decreases, and the iron salt content increases, so the pickling process cannot continue, at this time, new acid needs to be replaced, thereby producing iron-containing waste hydrochloric acid. The main components of the iron-containing waste hydrochloric acid are HCl, ferrous chloride and water, and their contents vary with pickling process, operating temperature, steel material quality and specifications. Generally, the content of ferrous iron is 7-12%, the content of HCl is 2-5%, and the density is generally 1.1-1.3 g / cm3. Iron-containing sludge refers to the waste water containing acid and ferrous ions generated in the water washing process after acid pickling of steel, and the acid and ferrous ions in the waste water are removed by neutralization treatment, and the filter residue is generated after flocculation and sedimentation. The main components of the iron-containing sludge are iron hydroxide and water.

[0003] At present, for the harmless treatment of iron-containing waste hydrochloric acid and iron-containing sludge, chemical neutralization method is generally used, and alkali solution is added for neutralization reaction. The addition of waste alkali can reduce the addition of part of reagents, but the amount of waste acid produced on the market is greater than the amount of waste alkali, so additional alkali solution must be added, thereby increasing the treatment cost. Therefore, some comprehensive utilization systems are proposed in the industry, such as patent CN202860147U, which relates to an acid pickling waste liquid recovery treatment device. The device can realize zero discharge of waste acid liquid by heating and evaporating the waste acid liquid, condensing the waste acid liquid in the condenser, forming dilute acid liquid which can be returned to the workshop for reuse, evaporating and concentrating, and precipitating solid crystals from the concentrated liquid. The patent can obtain dilute acid and FeCl2 solid by evaporation and crystallization, which has certain economic benefits, but the disadvantages are: the incoming waste acid fluctuates and generally contains certain impurities, and the scheme does not have pretreatment measures at the front end, which causes the quality of the final product to be uncontrollable. Since FeCl2 solid needs to be obtained by crystallization, a larger evaporation capacity and a higher concentration multiple are required for the treatment of waste acid of the same scale, which further causes the boiling point of the material to be higher, thereby making the equipment investment scale larger, the operation cost higher, and the selection of materials more difficult.

[0004] In summary, although the existing treatment methods for iron-containing waste hydrochloric acid and iron-containing sludge have achieved resource utilization of waste to a certain extent, there are still many problems, such as uncontrollable product quality and high treatment cost. UTILITY MODEL CONTENT

[0005] In order to overcome at least one of the above-mentioned defects of the prior art, the utility model provides iron containing waste hydrochloric acid and sludge resource utilization production ferric chloride water purifying agent system.

[0006] The utility model discloses a technical scheme that is adopted to solve the problem, which is iron containing waste hydrochloric acid and sludge resource utilization production ferric chloride water purifying agent system, comprising: a pretreatment module, the pretreatment module includes dissolving acidification tank, impurity removal filtrate tank, acidification blending tank and oxidation synthesis kettle, is used for carrying out pretreatment to iron containing waste hydrochloric acid and iron containing sludge, a feed buffer module, the feed buffer module includes feed buffer tank and feed pump, is used for buffering the material after being handled by the pretreatment module, a preheating module, the preheating module includes primary preheater and secondary preheater, is used for preheating treatment to the material, a three-effect evaporation concentration module, including one effect evaporator, two effect evaporator, three effect evaporator and last effect condenser, is used for evaporation concentration treatment to the material, a vacuum module, the vacuum module is used for providing vacuum environment for three effect evaporation concentration module, shaft seal water module, the shaft seal water module is used for providing circulating machine seal cooling water for three effect evaporation concentration module, cooling water circulation module, the cooling water circulation module is used for providing circulating cooling water for three effect evaporation concentration module, instrument electric control module, the instrument electric control module is used for controlling the operation between each module.

[0007] By adopting the above scheme, iron containing waste hydrochloric acid and iron containing sludge can be converted into ferric chloride water purifying agent, realizing the resource utilization of waste, meeting the concept of environmental protection and resource recycling, and directly obtaining liquid ferric chloride water purifying agent through evaporation concentration treatment of the system, without further evaporation crystallization of salt, simplifying the production process, and the product can be directly used as a water purifying agent without further water preparation.

[0008] Further, the pretreatment module further comprises an acid solution transfer pump, an impurity removal filter pump, a filter press, a filtrate pump and a blending discharge pump, the acid solution transfer pump is arranged between the dissolving acidification tank and the impurity removal filtrate tank, the filter press is arranged between the impurity removal filtrate tank and the acidification blending tank, the filtrate pump is arranged between the impurity removal filtrate tank and the filter press, and the blending discharge pump is arranged between the filter press and the oxidation synthesis kettle.

[0009] By adopting the above scheme, the solution in the pretreatment process is ensured to run smoothly.

[0010] Further, the primary preheater is connected with a discharge buffer tank, which also communicates with the three-effect evaporator, and is used to store the concentrated material reaching a certain concentration and cooled by the primary preheater.

[0011] By adopting the above scheme, the material reaching a certain concentration in the three-effect evaporator can be stored in the discharge buffer tank after being cooled by the primary preheater, so as to realize the conversion of liquid water treatment agent.

[0012] Further, the primary evaporator is also connected with a clean condensate tank, which communicates with the secondary preheater and is used to collect clean condensate for recycling; and the final-effect condenser is also connected with a dirty condensate tank for collecting dirty condensate.

[0013] By adopting the above scheme, the clean condensate tank is used to collect the clean condensate generated by the primary evaporator, which is formed in the evaporation process due to the condensation of steam and is not contaminated by impurities in the evaporated material, so it has high recycling value and can be used for preheating or other links requiring pure water in the system, which reduces the discharge of waste water and reduces the pollution to the environment.

[0014] Further, the primary evaporator includes a primary heater, a primary separator, a primary circulating pump and a primary transfer pump, the secondary evaporator includes a secondary heater, a secondary separator, a secondary circulating pump and a secondary transfer pump, and the three-effect evaporator includes a three-effect heater, a three-effect separator, a three-effect circulating pump and a three-effect transfer pump, the primary circulating pump, the secondary circulating pump and the three-effect circulating pump are used to uniformly distribute the material liquid between the evaporators, and the primary transfer pump, the secondary transfer pump and the three-effect transfer pump are used for material transfer.

[0015] By adopting the above scheme, the existence of the circulating pump and the transfer pump not only improves the evaporation efficiency, but also ensures the smooth transfer of the material between the evaporators, so as to realize the precise control of the entire evaporation process.

[0016] Further, the primary circulating pump adopts a small-flow clamp fluorine centrifugal pump, the secondary circulating pump also adopts a small-flow clamp fluorine centrifugal pump, and the three-effect circulating pump adopts a large-flow clamp fluorine axial flow pump.

[0017] By adopting the above scheme, the flow of the material liquid of the primary circulating pump and the secondary circulating pump is also relatively small, so the small-flow clamp fluorine centrifugal pump can complete the circulating treatment, and the continuous circulation of the material liquid improves the evaporation efficiency and ensures the continuity of the evaporation process. The flow of the material liquid treated by the three-effect evaporator is large, so the selection of the large-flow circulating pump can ensure the continuity and high efficiency of the evaporation process.

[0018] Further, the filter press is a diaphragm filter press.

[0019] By adopting the above scheme, the diaphragm filter press has high efficient solid-liquid separation capacity, can ensure that the moisture content of the filter cake reaches a low level, thereby improving the purity and quality of the product.

[0020] Further, the dissolving acidification tank is provided with a stirring device.

[0021] By adopting the above scheme, the stirring device can ensure that the iron-containing waste hydrochloric acid and the raw materials such as sludge are fully mixed in the dissolving acidification tank, so as to avoid local concentration being too high or too low, thereby ensuring the uniformity and consistency of the reaction.

[0022] Further, the vacuum module adopts a jet spray vacuum unit.

[0023] By adopting the above scheme, the smooth progress of the production process and the purity of the product are ensured, and the production efficiency is improved and the operating cost is reduced.

[0024] Further, the instrument electric control module comprises a main controller and a plurality of temperature sensors and a plurality of pressure sensors, and the temperature sensors and the pressure sensors are electrically connected with the main controller.

[0025] By adopting the above scheme, the temperature, pressure and other key parameters in the production process are monitored in real time, and the data are transmitted to the main controller for processing and analysis. The main controller adjusts and controls the production process in real time according to the preset logic and algorithm, so as to ensure the product quality and production efficiency, and intelligent control can be realized.

[0026] In summary, the system for producing ferric chloride water purifying agent by utilizing iron-containing waste hydrochloric acid and sludge has the following technical effects:

[0027] 1. The system can convert the two wastes, iron-containing waste hydrochloric acid and iron-containing sludge, into ferric chloride water purifying agent, which not only solves the problem of waste treatment, but also realizes effective recycling and utilization of resources, in line with the concept of environmental protection and resource recycling;

[0028] 2. Through the treatment of the system, liquid ferric chloride water purifying agent can be directly obtained without further evaporation and crystallization of salt, thereby simplifying the production process and reducing the treatment cost. In addition, the pretreatment module provided by the system can effectively remove impurities in the waste acid and sludge, ensure the quality of the final product, and reduce the additional cost caused by product quality problems;

[0029] 3. The system adopts modern production technology and equipment, such as three-effect evaporation and concentration module, vacuum module, etc., which can realize rapid and efficient treatment of materials. At the same time, the instrument electric control module can accurately control the operation between modules, ensure the stability and continuity of the whole production process, and improve the production efficiency;

[0030] 4. The system reduces environmental pollution and damage caused by waste through effective waste treatment and resource utilization. At the same time, the system can properly handle the pollutants such as wastewater and waste gas generated during production to ensure that the emissions meet the standards and reduce the environmental risk;

[0031] 5. Because the system is equipped with a pretreatment module, including steps such as dissolution acidification, impurity removal, acidification adjustment, and oxidation synthesis, these steps can effectively remove impurities in waste acid and sludge, ensuring that the quality of the final product is stable and controllable. This not only improves the market competitiveness of the product, but also provides users with a better user experience;

[0032] 6. The implementation of the system helps to promote the sustainable development of the steel, chemical, and other industries. By realizing the resource utilization of waste and reducing the processing cost, the system can provide a more economical and environmentally friendly waste treatment solution for the relevant industries, promoting the green development of the entire industry. BRIEF DESCRIPTION OF DRAWINGS

[0033] Fig. 1 The system flow structure diagram of the embodiment of the present application;

[0034] Fig. 2 The pretreatment module structure diagram of the embodiment of the present application;

[0035] Fig. 3 The three-effect evaporation concentration module structure diagram of the embodiment of the present application.

[0036] Among them, the meaning of the reference signs is as follows: 1, pretreatment module; 11, dissolution acidification tank; 111, stirring device; 12, acid solution transfer pump; 13, impurity removal filtrate tank; 14, impurity removal pressure filtration pump; 15, pressure filter; 16, filtrate pump; 17, acidification adjustment tank; 18, adjustment discharge pump; 19, oxidation synthesis kettle; 2, feed buffer module; 21, feed buffer tank; 22, feed pump; 3, preheating module; 31, first-stage preheater; 32, second-stage preheater; 4, three-effect evaporation concentration module; 41, first-effect evaporator; 411, first-effect heater; 412, first-effect separator; 413, first-effect circulating pump; 414, first-effect transfer pump; 42, second-effect evaporator; 421, second-effect heater; 422, second-effect separator; 423, second-effect circulating pump; 424, second-effect transfer pump; 43, third-effect evaporator; 431, third-effect heater; 432, third-effect separator; 433, third-effect circulating pump; 434, third-effect transfer pump; 44, last-effect condenser; 5, vacuum module; 6, shaft seal water module; 7, cooling water circulation module; 8, discharge buffer tank; 9, clean condensate water tank; 10, dirty condensate water tank. DETAILED DESCRIPTION

[0037] For better understanding and implementation, the technical solutions in the embodiments of the present application will be described and discussed clearly and completely in conjunction with the drawings of the present application. Obviously, only some examples of the present application are described here, and not all examples. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the present application.

[0038] For the convenience of understanding the embodiments of the present application, the following will be further explained and described with specific examples in conjunction with the drawings, and each embodiment does not constitute a limitation on the embodiments of the present application.

[0039] In the description of the present application, it should be pointed out that the orientation or position relationship indicated by the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like is based on the orientation or position relationship shown in the drawings, and is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, therefore it cannot be understood as a limitation on the present application.

[0040] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which the present application belongs. The terms used in the specification of the present application are only for the purpose of describing the specific embodiments, and are not intended to limit the present application.

[0041] Embodiment 1 of the present application refers to Figs. 1-3As shown, the system for producing ferric chloride water purifying agent by resource utilization of waste hydrochloric acid containing iron and sludge is disclosed, which comprises a pretreatment module 1, a feed buffer module 2, a preheating module 3, a three-effect evaporation and concentration module 4, a vacuum module 5, a shaft seal water module 6, a cooling water circulation module 7 and an instrument and electric control module, the pretreatment module 1 comprises a dissolution acidification tank 11, a impurity removal filtrate tank 13, an acidification and preparation tank 17 and an oxidation synthesis kettle 19 which are sequentially communicated, for pretreating waste hydrochloric acid containing iron and sludge containing iron, the feed buffer module 2 comprises a feed buffer tank 21 and a feed pump 22, for buffering the material treated by the pretreatment module 1, the preheating module 3 comprises a first-stage preheater 31 and a second-stage preheater 32 which are sequentially connected, the first-stage preheater 31 and the second-stage preheater 32 are connected to a discharge port of the feed buffer tank 21, for preheating the material, the three-effect evaporation and concentration module 4 comprises a first-effect evaporator 41, a second-effect evaporator 42, a third-effect evaporator 43 and a last-effect condenser 44, for evaporating and concentrating the material, the vacuum module 5 is used for providing a vacuum environment for the three-effect evaporation and concentration module 4, the shaft seal water module 6 is used for providing circulating mechanical seal cooling water for the three-effect evaporation and concentration module 4, the cooling water circulation module 7 is used for providing circulating cooling water for the three-effect evaporation and concentration module 4, and the instrument and electric control module is used for controlling the operation between the modules, so that the waste hydrochloric acid containing iron and the sludge containing iron can be converted into the ferric chloride water purifying agent, the resource utilization of waste is realized, the concept of environmental protection and resource recycling is met, the liquid ferric chloride water purifying agent is directly obtained through the evaporation and concentration treatment of the system, further evaporation and crystallization are not needed, the production process is simplified, the product can be directly used as the water purifying agent, and water preparation is not needed again; the pretreatment module 1 is provided, which comprises steps of dissolution acidification, impurity removal, acidification and preparation and oxidation synthesis, so that the impurities in the waste acid and the sludge can be effectively removed, and the quality of the final product is stable and controllable.

[0042] In some embodiments, the pretreatment module 1 further comprises an acid solution transfer pump 12, an impurity removal filter pump 14, a filter press 15, a filtrate pump 16 and a preparation discharge pump 18, the acid solution transfer pump 12 is arranged between the dissolution acidification tank 11 and the impurity removal filtrate tank 13, the filter press 15 is arranged between the impurity removal filtrate tank 13 and the acidification and preparation tank 17, the filtrate pump 16 is arranged between the impurity removal filtrate tank 13 and the filter press 15, and the preparation discharge pump 18 is arranged between the filter press 15 and the oxidation synthesis kettle 19, so as to ensure the smooth operation of the solution in the pretreatment process. In order to facilitate the collection of the liquid water purifying agent, a discharge buffer tank 8 is connected after the third-effect evaporator 43.

[0043] The operation steps of the system for producing ferric chloride water purifying agent by utilizing iron-containing waste hydrochloric acid and sludge are as follows: firstly, the collected iron-containing waste hydrochloric acid and iron-containing sludge are fully dissolved in the dissolving and acidifying tank 11, and hydrochloric acid or iron oxide skin is supplemented according to the actual situation, and then a decontaminating agent and a heavy metal capturing agent are added to chemically precipitate heavy metals and other impurities, and after pressure filtration by the filter press 15, the filtrate is introduced into the acidifying and blending tank 17, and hydrochloric acid is added to blend the proportion, and then a catalyst is added to the oxidation synthesis kettle 19, and oxygen is introduced for catalytic oxidation, so as to obtain a dilute ferric chloride solution, and after the dilute solution is introduced into the feed buffer tank 21, it is sequentially introduced into the first evaporator 41, the second evaporator 42 and the third evaporator 43 for evaporation and concentration, and after reaching the required concentration, the product is discharged and cooled to be introduced into the discharge buffer tank 8.

[0044] In order to effectively utilize the temperature of the concentrated liquid water purifying agent with high temperature, in some embodiments, the discharge buffer tank 8 is connected with the first preheater 31 for cooling the concentrated liquid water purifying agent with high temperature, so as to facilitate the storage of the discharge buffer tank 8.

[0045] In order to recycle the clean condensed water condensed in the first evaporator 41, in some embodiments, the first evaporator 41 is further connected with the clean condensed water tank 9, which is communicated with the second preheater 32 for collecting and recycling the clean condensed water; the clean condensed water tank 9 is used to collect the clean condensed water generated by the first evaporator 41, which is formed by condensation of steam in the evaporation process and is not contaminated by impurities in the evaporation material, so it has high recycling value and can be used for preheating or other links requiring pure water in the system, which reduces the discharge of waste water and reduces the pollution to the environment. The clean condensed water tank 9 is connected with a pumping system, which also serves as a water seal.

[0046] In some embodiments, the last-effect condenser 44 is further connected with the dirty condensed water tank 10 for collecting dirty condensed water, which can avoid environmental pollution after being collected and waiting for subsequent treatment. The dirty condensed water tank 10 is also connected with a pumping system, which also serves as a water seal.

[0047] In the embodiment 1, the single-effect evaporator 41 comprises a single-effect heater 411, a single-effect separator 412, a single-effect circulating pump 413 and a single-effect transfer pump 414, the double-effect evaporator 42 comprises a double-effect heater 421, a double-effect separator 422, a double-effect circulating pump 423 and a double-effect transfer pump 424, the triple-effect evaporator 43 comprises a triple-effect heater 431, a triple-effect separator 432, a triple-effect circulating pump 433 and a triple-effect transfer pump 434, the single-effect circulating pump 413, the double-effect circulating pump 423 and the triple-effect circulating pump 433 are used to evenly distribute the material liquid between the evaporators of different levels, and the single-effect transfer pump 414, the double-effect transfer pump 424 and the triple-effect transfer pump 434 are used for transfer conveying. Due to the existence of the circulating pumps and the transfer pumps, not only the evaporation efficiency is improved, but also the smooth transfer of the material between the evaporators of different levels is ensured, so that the accurate control of the whole evaporation process is realized.

[0048] Optionally, in order to improve intelligent control, a plurality of temperature sensors and a plurality of pressure sensors are additionally arranged on the instrument electric control module, and are arranged on the connecting pipelines between each module. The instrument electric control module comprises a main controller, and the temperature sensors and the pressure sensors are electrically connected to the main controller. By monitoring the temperature, pressure and other key parameters in the production process in real time, the data is transmitted to the main controller for processing and analysis. The main controller adjusts and controls the production process in real time according to the preset logic and algorithm, so as to ensure the product quality and production efficiency, and intelligent control can be realized.

[0049] In the embodiment 1, the vacuum module 5 adopts a jet spray vacuum unit, which comprises a water tank, a buffer tank, a corrosion-resistant centrifugal pump, a water jet pump and a cooler. The unit has a limit vacuum of-0.095 MPa, which ensures that the system evaporates at a low temperature under a high vacuum degree. The unit as a whole adopts a material with excellent corrosion resistance. The circulating liquid pump adopts a plastic-lined centrifugal pump, the water jet pump, the buffer tank and the water tank adopt RPP material, and the cooler adopts a PP modified graphite heat exchanger.

[0050] In some embodiments, the shaft seal water module 6 comprises a shaft seal water tank, a shaft seal water pump, a shaft seal water cooler and the like, which provides internal circulating seal cooling water for the pump of the triple-effect evaporation and concentration module 4, lubricates and cools the seal, prolongs the service life of the seal, and simultaneously detects the pressure and electrical conductivity to monitor the use of the seal and to alarm and interlock control in abnormal conditions. Since the shaft seal water module 6 is prior art, it will not be described in detail here.

[0051] In some embodiments, the cooling water module specifically comprises a cooling water tower, a cooling water circulating pump, a cold water pool and a cooling water bypass filter, which is used to provide circulating cooling water for the triple-effect evaporation and concentration module 4. Since the cooling water module is prior art, it will not be described in detail here.

[0052] To understand the operation process and working principle of the system, the embodiment 1 is taken as an example to be introduced in detail. The iron-containing sludge is put into the dissolution acidification tank 11 and the feeding port is closed. The dissolution acidification tank 11 is provided with a stirring device 111 in the embodiment 1. The iron-containing waste hydrochloric acid and the appropriate amount of hydrochloric acid are added into the dissolution acidification tank 11 through the pipeline. The dissolution is fully stirred by the stirring device 111 under normal temperature and pressure. The main chemical reaction equation is as follows:

[0053] 2HCl + Fe(OH)2 = FeCl2 + 2H2O

[0054] 3HCl + 2Fe(OH)3 = 2FeCl3 + 3H2O

[0055] If the amount of the iron-containing waste hydrochloric acid is insufficient or the iron content in the iron-containing waste hydrochloric acid is insufficient, the iron-containing waste hydrochloric acid or the hydrochloric acid can be used to react with the excess iron oxide skin to generate a reaction liquid for the next process.

[0056] The chemical reaction equation is as follows:

[0057] 2HCl + FeO = FeCl2 + H2O

[0058] 6HCl + Fe2O3 = 2FeCl3 + 3H2O

[0059] 8HCl + Fe3O4 = 2FeCl3 + FeCl2 + 4H2O

[0060] The above dissolution solution is transferred to the impurity removal tank by the acid solution transfer pump 12. The impurity removal agent is added. The impurity removal agent is preferably Na2S or other metal capturing agent. The impurity removal agent reacts with the metal impurities to form a precipitate. The chemical reaction equation is as follows:

[0061] MCl x + Na2S → MS↓ + NaCl

[0062] The solution added with the impurity removal agent is sent to the filter press 15 by the impurity removal pressure filtration pump 14. The filter press 15 is preferably a diaphragm filter press 15 with high solid-liquid separation capacity, which can ensure that the water content of the filter cake reaches a low level, thereby improving the purity and quality of the product. After the filter press 15, the heavy metal impurities enter the mud cake, and the filter press filtrate is purified.

[0063] The filtrate is then transferred to an acidification preparation tank 17 by a filtrate pump 16, and a certain amount of hydrochloric acid is added to the acidification preparation tank 17 to adjust the ratio of FeCl2 to hydrochloric acid. The FeCl2 filtrate is prepared, and then the FeCl2 filtrate is transferred to an oxidation reaction kettle through a preparation discharge pump 18, a catalyst, preferably sodium nitrite, is added, and oxygen is introduced to perform an oxidation reaction, to generate a dilute ferric chloride solution with a mass concentration of 23-29% and an acidity of 0.1-0.5%. The chemical reaction equation is as follows:

[0064] 4FeCl2+4HCl+O2=4FeCl3+2H2O

[0065] The dilute ferric chloride solution synthesized by subsequent oxidation is transported to a feed buffer tank 21 by a feed pump 22 for storage before evaporation and concentration. The dilute ferric chloride solution is warmed through two-stage preheating. The first-stage preheating heat source uses discharge concentrated liquid, and the second-stage preheating heat source uses clean condensate water. The preheated material enters a three-effect evaporation system.

[0066] Specifically, the first-stage preheater 31 uses a double-pass graphite corrosion-resistant heat exchanger. The tube side and shell side both use modified phenolic resin high-temperature impregnated graphite. The graphite blocks are connected by a ladder-type four-fluorine elastic belt. The graphite pipe joints are provided with molded four-fluorine expansion joints, which have excellent corrosion resistance and good heat transfer effect. The preheater tube side medium is dilute ferric chloride solution, and the four-flow design is used. The shell side medium is ferric chloride concentrated liquid. The second-stage preheater 32 uses a single-pass graphite corrosion-resistant heat exchanger. The tube side uses modified phenolic resin high-temperature impregnated graphite block heat exchanger, and the shell side uses carbon steel, which has excellent corrosion resistance and good heat transfer coefficient. The preheater tube side medium is dilute ferric chloride solution, and the four-flow design is used. The shell side medium is saturated steam condensate water. It should be noted that in other embodiments, the specific materials and structures of the first-stage preheater 31 and the second-stage preheater 32 are not limited.

[0067] The preheated material continues to enter the first evaporator 41, which is composed of a first heater 411, a first separator 412 and a first circulating pump 413. The first evaporator 41 adopts an external heating type self-circulation process, saturated steam at 0.4-0.6 MPa (G) is introduced into the shell side of the heater, and the material flows through the tube side of the heater. The material is heated by the steam to generate a hot driving force, and the material flows automatically. A first circulating pump 413 is provided, so that the circulating pump can be started according to the need to speed up the flow of the material, so as to improve the heat transfer effect. The heated material enters the first separator 412 for flash evaporation, the secondary steam of the flash evaporation enters the second evaporator 42 as a heating heat source, and the concentrated liquid is pumped into the second evaporator for further evaporation and concentration. Optionally, the heating saturated steam can be provided with a steam cylinder to improve the stability of the heating steam. Preferably, the first heater 411 adopts a single-pass graphite corrosion-resistant heat exchanger, the tube side adopts a modified phenolic resin high-temperature impregnated graphite block heat exchanger, and the shell side adopts carbon steel material, which has excellent corrosion resistance and good heat transfer effect; the tube side medium of the heater is ferric chloride solution, and the shell side medium is saturated steam. The first separator 412 is made of glass fiber reinforced plastic, the resin is 2960# vinyl resin, and the glass fiber is EWR2400TE. The normal temperature resistance is below 130°C, and the ultimate temperature resistance is 140°C, which meets the requirements of high temperature and strong corrosion of the system. At the same time, compared with the graphite separator, the cost is greatly reduced. The first circulating pump 413 adopts a small-flow clamp plate fluorine (PFA) centrifugal pump, and all the flow parts are made of high-grade fluorine material PFA, which can resist high temperature above 180°C. At the same time, the pump is modified with high-grade carbon fiber, graphene and rutile nano materials, which greatly improves the wear resistance and service life of the pump.

[0068] The material after the first-effect concentration enters the second-effect evaporator 42, which is composed of a second-effect heater 421, a second-effect separator 422 and a second-effect circulating pump 423. The second-effect evaporator 42 adopts an external heating type self-circulation process. The secondary steam from the first-effect flash evaporation is introduced into the heater shell side, and the material flows through the heat exchanger tube side. The material is heated by the secondary steam to generate a thermal driving force, and the material flows automatically. The scheme also adds the second-effect circulating pump 423. The circulating pump can be started according to the need to speed up the flow of the material, so as to improve the heat transfer effect. The heated material enters the second-effect separator 422 for flash evaporation. The flash evaporated secondary steam enters the third-effect evaporator 43 as a heating heat source, and the concentrated liquid is pumped into the third-effect evaporator for further evaporation and concentration. Preferably, the bottom condensate outlet of the second-effect heater 421 is connected to the bottom of the third-effect heater 431 by a U-shaped bend. The second-effect heater 421 adopts a double-pass graphite corrosion-resistant heat exchanger. The tube side and the shell side both adopt modified phenolic resin high-temperature impregnated graphite, which has excellent corrosion resistance and good heat transfer effect. The tube side medium is ferric chloride solution, and the single-flow design is adopted. The shell side medium is secondary steam. The second-effect separator 422 has the same material type as the first-effect separator 412. The second-effect circulating pump 423 has the same material type and size as the first-effect circulating pump 413. The material liquid flow of the first-effect circulating pump 413 and the second-effect circulating pump 423 is relatively small. Therefore, the small-flow clamp fluorine centrifugal pump can complete the circulation treatment. Through continuous circulation of the material liquid, the evaporation efficiency is improved, and the continuity of the evaporation process is ensured.

[0069] The material after the two-effect concentration enters a three-effect evaporator 43, which is composed of a three-effect heater 431, a three-effect separator 432 and a three-effect circulating pump 433. The three-effect evaporator 43 adopts a forced circulation process, and the flow of the material is accelerated by the forced circulation pump to improve the heat transfer effect. The heated material enters the three-effect separator 432 for flash evaporation, and the secondary steam of the flash evaporation enters the final-effect condenser 44 to be condensed into dirty condensed water. The concentrated liquid reaches a mass concentration of 38-43.5% and is discharged, and finally enters the discharge buffer tank 8. Preferably, the three-effect heater 431 adopts a double-pass graphite corrosion-resistant heat exchanger, and the tube and shell pass adopt modified phenolic resin high-temperature impregnated graphite, which has excellent corrosion resistance and good heat transfer effect. The tube pass medium of the heater is ferric chloride solution, and the shell pass medium is secondary steam. The three-effect separator 432 adopts glass steel material, the resin adopts 2960# ethylene resin, and the glass fiber adopts EWR2400TE. The normal temperature resistance is below 130 DEG C, the limit temperature resistance is 140 DEG C, the limit pressure resistance is -0.1 MPa (G), which meets the working condition requirements of high temperature, strong corrosion and high vacuum of the system, and the cost is greatly reduced compared with the graphite separator. The three-effect circulating pump 433 adopts a large-flow clamping plate fluorine (PFA) axial flow pump, and all the flow parts use high-grade fluorine material PFA, which can resist high temperature above 180 DEG C. At the same time, the pump is modified to increase high-grade carbon fiber, graphene and rutile nano, which greatly improves the wear resistance and service life of the pump. The three-effect evaporator 43 processes a large amount of liquid flow, so the selection of the large-flow circulating pump can ensure the continuity and efficiency of the evaporation process.

[0070] The secondary steam of the flash evaporation of the three-effect separator 432 enters the final-effect condenser 44 for condensation. The condenser adopts a single-pass graphite corrosion-resistant heat exchanger, the tube pass adopts a modified phenolic resin high-temperature impregnated graphite block heat exchanger, and the shell pass adopts carbon steel material, which has excellent corrosion resistance and good heat transfer coefficient. The condenser tube pass medium is secondary steam, and the shell pass medium is circulating cooling water. The final-effect condenser 44 collects the dirty condensed water through the dirty condensed water tank 10 and waits for subsequent processing.

[0071] In summary, the system for producing ferric chloride water purifying agent from iron-containing waste hydrochloric acid and sludge has the following technical effects:

[0072] 1. The system can convert the two wastes of iron-containing waste hydrochloric acid and iron-containing sludge into ferric chloride water purifying agent, which not only solves the problem of waste treatment, but also realizes effective recycling and utilization of resources, and meets the concept of environmental protection and resource recycling.

[0073] 2. The system can directly obtain liquid ferric chloride water purifier without further evaporation and crystallization of salt, simplifying the production process and reducing the processing cost. In addition, the pretreatment module 1 of the system can effectively remove impurities in waste acid and sludge, ensuring the quality of the final product is stable and controllable, reducing additional costs due to product quality problems;

[0074] 3. The system uses modern production technology and equipment, such as three-effect evaporation and concentration module 4 and vacuum module 5, which can realize rapid and efficient treatment of materials. At the same time, the instrument and electric control module can accurately control the operation between modules, ensuring the stability and continuity of the entire production process, thereby improving the production efficiency;

[0075] 4. The system reduces environmental pollution and damage by effectively treating and recycling waste. At the same time, the pollutants such as wastewater and waste gas generated during the production process can also be properly treated to ensure standard discharge and reduce environmental risks;

[0076] 5. The system is equipped with a pretreatment module 1, including dissolution and acidification, impurity removal, acidification adjustment, and oxidation synthesis, which can effectively remove impurities in waste acid and sludge, ensuring the quality of the final product is stable and controllable. This not only improves the market competitiveness of the product, but also provides users with a better user experience;

[0077] 6. The implementation of the system helps to promote the sustainable development of the steel, chemical and other industries. By realizing the resource utilization of waste and reducing the processing cost, the system can provide more economical and environmentally friendly waste treatment solutions for related industries, promoting the green development of the entire industry.

[0078] The technical means disclosed in the utility model scheme are not limited to the technical means disclosed in the above-mentioned embodiments, but also include technical solutions composed of any combination of the above technical features. It should be noted that for ordinary skilled persons in the art, without departing from the principles of the utility model, some improvements and refinements can be made, which are also considered within the protection scope of the utility model.

Claims

1. A system for producing ferric chloride water purifying agent by resource utilization of iron-containing waste hydrochloric acid and sludge, characterized in that, The application relates to a waste hydrochloric acid and sludge treatment device, which comprises the following modules: a pretreatment module (1) for pretreating waste hydrochloric acid and sludge, a feed buffer module (2) for buffering the pretreated material, a preheating module (3) for preheating the material, a three-effect evaporation and concentration module (4) for evaporating and concentrating the material, a vacuum module (5) for providing a vacuum environment for the three-effect evaporation and concentration module (4), a shaft seal water module (6) for providing circulating shaft seal cooling water for the three-effect evaporation and concentration module (4), a cooling water circulation module (7) for providing circulating cooling water for the three-effect evaporation and concentration module (4), and an instrument electric control module for controlling the operation of the modules. The pretreatment module (1) further comprises an acid solution transfer pump (12), a filter pressing pump (14), a filter press (15), a filtrate pump (16) and a dispensing discharge pump (18), the acid solution transfer pump (12) is arranged between the dissolving and acidifying tank (11) and the impurity removal filtrate tank (13), the filter press (15) is arranged between the impurity removal filtrate tank (13) and the acidification and dispensing tank (17), the filtrate pump (16) is arranged between the impurity removal filtrate tank (13) and the filter press (15), and the dispensing discharge pump (18) is arranged between the filter press (15) and the oxidation synthesis kettle (19). The first-stage preheater (31) is connected with a discharge buffer tank (8), the discharge buffer tank (8) also communicates with the three-effect evaporator (43), and the discharge buffer tank (8) is used for storing the concentrated material reaching a concentration and cooled by the first-stage preheater (31). The one-effect evaporator (41) is further connected with a clean condensate water tank (9) which communicates with the second-stage preheater (32) and is used for collecting clean condensate water for recycling; and the last-effect condenser (44) is further connected with a dirty condensate water tank (10) for collecting dirty condensate water. ​ ​ ​ ​ ​ 2. The system for resource utilization of iron-containing waste hydrochloric acid and sludge to produce ferric chloride water purifying agent according to claim 1, characterized in that, ​ 3. The system for resource utilization of iron-containing waste hydrochloric acid and sludge to produce ferric chloride water purifying agent according to claim 1, characterized in that, ​ 4. The system for resource utilization of iron-containing waste hydrochloric acid and sludge to produce ferric chloride water purifying agent according to claim 1, characterized in that, ​ 5. The system for resource utilization of iron-containing waste hydrochloric acid and sludge to produce ferric chloride water purifying agent according to claim 1, characterized in that, The primary evaporator (41) comprises a primary heater (411), a primary separator (412), a primary circulating pump (413) and a primary transfer pump (414), the secondary evaporator (42) comprises a secondary heater (421), a secondary separator (422), a secondary circulating pump (423) and a secondary transfer pump (424), the tertiary evaporator (43) comprises a tertiary heater (431), a tertiary separator (432), a tertiary circulating pump (433) and a tertiary transfer pump (434), the primary circulating pump (413), the secondary circulating pump (423) and the tertiary circulating pump (433) are used for uniformly distributing the material liquid between the evaporators of different stages, and the primary transfer pump (414), the secondary transfer pump (424) and the tertiary transfer pump are used for transferring and conveying.

6. The system for resource utilization of iron-containing waste hydrochloric acid and sludge to produce ferric trichloride water purifying agent according to claim 5, characterized in that, The primary circulating pump (413) adopts a small-flow clamped fluorine centrifugal pump, the secondary circulating pump (423) adopts a small-flow clamped fluorine centrifugal pump, and the tertiary circulating pump (433) adopts a large-flow clamped fluorine axial flow pump.

7. The system for resource utilization of iron-containing waste hydrochloric acid and sludge to produce ferric trichloride water purifying agent according to claim 2, characterized in that, The filter press (15) is a diaphragm filter press (15).

8. The system for resource utilization of iron-containing waste hydrochloric acid and sludge to produce ferric trichloride water purifying agent according to claim 1, characterized in that, The dissolving and acidifying tank (11) is provided with a stirring device (111).

9. The system for resource utilization of iron-containing waste hydrochloric acid and sludge to produce ferric trichloride water purifying agent according to claim 1, characterized in that, The vacuum module (5) adopts a jet injection vacuum unit.

10. The system for resource utilization of iron-containing waste hydrochloric acid and sludge to produce ferric trichloride water purifying agent according to claim 1, characterized in that, The instrument electric control module comprises a main controller and a plurality of temperature sensors and a plurality of pressure sensors, and the temperature sensors and the pressure sensors are electrically connected with the main controller.

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