System for producing high-purity ferrous chloride by using desiliconized purified waste acid

Abstract

The utility model provides a system for producing high-purity ferrous chloride by using desiliconized purified waste acid. The system for producing the high-purity ferrous chloride by using the desiliconized purified waste acid comprises a purification system and a purification system, the purification system comprises a neutralizing tower, a reaction tank, a mixing tank, a settling tank and a purified waste acid tank which are arranged in sequence, and the purification system comprises an evaporator, a centrifugal separator, a stirring and dissolving tank and a ferrous chloride storage tank which are arranged in sequence. An inlet of the evaporator is communicated with an outlet of the purified waste acid tank. The system disclosed by the utility model can be used for regenerating and producing a high-quality iron oxide red product meeting the standard by utilizing waste acid.

Description

Technical Field

[0001] The utility model relates to the technical field of waste acid regeneration, in particular to a system for producing high-purity ferrous chloride by utilizing desiliconization to purify waste acid. Background Art

[0002] The main components of waste acid generated during the pickling process in the cold rolling industry are water, FeCl2, HCl, trace metal ions such as manganese, aluminum, copper, calcium, and sodium that are soluble in the acid, and trace impurities such as silicon and phosphate that are insoluble in the acid. For environmental protection and resource recycling, the cold rolling pickling process must be equipped with an acid regeneration unit. Currently, the mainstream waste acid regeneration process generally uses spray roasting or fluidized bed roasting to produce HCl gas and red iron oxide through a high-temperature chemical reaction in the waste acid. The HCl gas is absorbed by water to form regenerated acid for use in the pickling process, and the red iron oxide is sold as a by-product. The red iron oxide produced as a by-product of waste acid regeneration is an important raw material for the magnetic materials industry. To obtain high-quality red iron oxide, the waste acid must be purified to remove harmful impurities. Only by producing qualified purified waste acid can high-quality red iron oxide be produced as a by-product during the acid regeneration process for use in the soft magnetic industry.

[0003] However, due to the multi-variety characteristics of cold-rolled steel grades, during the pickling process, the content of silicon, copper, manganese, etc. in the waste acid is much higher than the design value of the steel grade in the original process due to changes in the steel grade; at the same time, in order to reduce costs, the steel production process often requires the use of secondary water, which brings impurities such as calcium, sodium, and magnesium into the waste acid. Impurities such as silicon, copper, and aluminum can generate SiO2, Cu(OH)2, and Al(OH)3 that are difficult to dissolve in water in the ordinary desiliconization process, and are thus removed in the form of precipitation. However, impurities such as manganese, calcium, and sodium that are soluble in water cannot be removed during the neutralization flocculation precipitation desiliconization waste acid purification process, which leads to serious excess of impurities such as manganese, calcium, sodium, and magnesium in the iron oxide red produced by acid regeneration, which cannot meet the use requirements of the soft magnetic industry.

[0004] In view of this, the present utility model is proposed. Utility Model Content

[0005] The purpose of the utility model is to provide a system for producing high-purity ferrous chloride by using desiliconization to purify waste acid, and the system can regenerate waste acid to produce high-quality iron oxide red products that meet standards.

[0006] The utility model provides a system for producing high-purity ferrous chloride by utilizing desiliconization to purify waste acid. The system comprises a purification system and a purification system. The purification system comprises a neutralization tower, a reaction tank, a mixing tank, a sedimentation tank and a waste acid purification tank which are arranged in sequence. The purification system comprises an evaporator, a centrifugal separator, a stirring and dissolving tank and a ferrous chloride storage tank which are arranged in sequence. The inlet of the evaporator is connected to the outlet of the waste acid purification tank.

[0007] Furthermore, the neutralization tower is provided with a waste acid inlet, a crushed steel bar inlet and a waste acid outlet. A heating heat exchanger for heating the waste acid is provided at the inlet end of the waste acid inlet, and an electromagnetic crane for lifting the crushed steel bars to the neutralization tower is provided at the inlet end of the crushed steel bar inlet.

[0008] Furthermore, the reaction tank is provided with a waste acid inlet, an ammonia water inlet, a compressed air inlet and a waste acid outlet. A cooling heat exchanger for cooling the waste acid is provided at the inlet end of the waste acid inlet, and the ammonia water inlet is connected to the ammonia water tank.

[0009] Furthermore, a mixing tank is provided between the reaction tank and the sedimentation tank. The mixing tank is provided with a flocculant inlet, a waste acid inlet and a waste acid outlet. The flocculant inlet is communicated with the flocculant storage tank.

[0010] Furthermore, the flocculant storage tank is communicated with the flocculant dissolving tank, and the flocculant dissolving tank is provided with a flocculant outlet and a desalted water inlet.

[0011] Furthermore, the sedimentation tank is provided with a mixed liquid inlet, a purified waste acid outlet and a sediment outlet. The mixed liquid inlet is connected to the mixing tank, the purified waste acid outlet is connected to the purified waste acid tank, the sediment outlet is connected to the filter press, the filter press is provided with a filtrate outlet and a filter cake outlet, and the filtrate outlet is connected to the sedimentation tank.

[0012] Furthermore, the purified waste acid tank is provided with a purified waste acid inlet, a hydrochloric acid inlet and a purified waste acid outlet, and the purified waste acid outlet is connected to the evaporator through a heat exchanger.

[0013] Furthermore, the evaporator is provided with a purified waste acid inlet, a steam inlet and a ferrous chloride crystal outlet, and the ferrous chloride crystal outlet is connected to the centrifugal separator.

[0014] Furthermore, the stirring dissolver is provided with a ferrous chloride crystal inlet, a desalted water inlet and a ferrous chloride solution outlet, and the ferrous chloride solution outlet is connected to the ferrous chloride storage tank.

[0015] Furthermore, a spray roasting device is provided at the outlet end of the ferrous chloride storage tank.

[0016] The system of the utility model removes most of the free hydrochloric acid in the waste acid through a neutralization tower, generates ferric hydroxide through a reaction in a reaction tank, utilizes the flocculent structure of ferric hydroxide to adsorb acid-insoluble impurities such as silicon in the waste acid, and simultaneously adjusts the pH value to form hydroxide precipitates of metal ions such as Cu and Al in the waste acid, and then adds a flocculant through a mixing tank to remove the formed precipitates, floccules and other impurities through the flocculation and precipitation effect, thereby forming purified waste acid; in addition, the purified waste acid is evaporated and crystallized through an evaporator to produce pure ferrous chloride crystals, thereby leaving soluble impurities such as manganese, calcium, sodium, magnesium and the like in the mother liquor, and the ferrous chloride is dissolved in a stirring and dissolving tank to form a high-purity ferrous chloride solution, and the high-purity ferrous chloride solution can produce high-quality iron oxide red products that meet the standards through acid regeneration spray roasting. The system can adapt to the pickling of various steel grades in cold rolling pickling, which is beneficial to providing high-quality iron oxide red raw materials for the magnetic material industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the specific implementation methods of the utility model or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0018] Figure 1 This is a schematic diagram of the structure of a system for producing high-purity ferrous chloride by purifying waste acid through desiliconization.

[0019] Description of reference numerals:

[0020] 1: Neutralization tower; 2: Heating heat exchanger; 3: Cooling heat exchanger; 4: Reaction tank; 5: Ammonia water tank; 6: Flocculant dissolution tank; 7: Flocculant storage tank; 8: Mixing tank; 9: Sedimentation tank; 10: Filter press; 11: Electromagnetic crane; 12: Shredded steel bars; 13: Waste acid purification tank; 14: Heat exchanger; 15: Evaporator; 16: Centrifugal separator; 17: Stirring and dissolving tank; 18: Ferrous chloride storage tank. DETAILED DESCRIPTION

[0021] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of the present application. Unless otherwise specified, 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.

[0022] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular also includes the plural. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0023] The following will clearly and completely describe the technical solutions of the present invention in conjunction with the embodiments. Obviously, the embodiments described are only a part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0024] Example 1

[0025] Combine Figure 1 As shown, the system for producing high-purity ferrous chloride by desiliconization purification of waste acid in this embodiment includes a purification system and a purification system, the purification system includes a neutralization tower 1, a reaction tank 4, a mixing tank 8, a settling tank 9 and a purified waste acid tank 13 arranged in sequence, the purification system includes an evaporator 15, a centrifugal separator 16, a stirring and dissolving tank 17 and a ferrous chloride storage tank 18 arranged in sequence, and the inlet of the evaporator 15 is connected to the outlet of the purified waste acid tank 13.

[0026] The purification system is primarily used to purify waste acid to produce purified waste acid. It consists of a neutralization tower 1, a reaction tank 4, a mixing tank 8, a settling tank 9, and a purified waste acid tank 13. Neutralization tower 1 is equipped with a waste acid inlet, a shredded steel bar inlet, and a waste acid outlet. A heating heat exchanger 2 is installed at the waste acid inlet for heating the waste acid, and an electromagnetic hoist 11 is installed at the shredded steel bar inlet for hoisting shredded steel bars 12 into the neutralization tower 1. After being heated by the heating heat exchanger 2, the waste acid reacts with the shredded steel bars 12 in the neutralization tower 1. This reaction removes most of the free hydrochloric acid. The waste acid after reaction in the neutralization tower 1 then enters the reaction tank 4.

[0027] The reaction tank 4 is provided with a waste acid inlet, an ammonia water inlet, a compressed air inlet, and a waste acid outlet. A cooling heat exchanger 3 for cooling the waste acid is provided at the inlet end of the waste acid inlet, and the ammonia water inlet is connected to the ammonia water tank 5. The waste acid after the reaction in the neutralization tower 1 is cooled by the cooling heat exchanger 3 and then enters the reaction tank 4. At the same time, the ammonia water in the ammonia water tank 5 enters the reaction tank 4 through the ammonia water inlet. The pH value of the waste acid is adjusted by the ammonia water to generate a small amount of Fe(OH)2. Compressed air is then introduced into the reaction tank 4 through the compressed air inlet to oxidize the Fe(OH)2 into Fe(OH)3. Fe(OH)3 has a stable flocculent structure. The characteristics of the Fe(OH)3 flocculent structure are used to adsorb acid-insoluble impurities such as silicon in the waste acid. At the same time, in the process of adjusting the pH value with ammonia water, metal ions such as Cu and Al in the waste acid will form hydroxide precipitates. The above two effects can achieve the purpose of removing impurities in the waste acid.

[0028] After the reaction in reactor 4, the spent acid then enters mixing tank 8, which is equipped with a flocculant inlet, a spent acid inlet, and a spent acid outlet. The flocculant inlet is connected to flocculant storage tank 7. Flocculant storage tank 7 is connected to flocculant dissolution tank 6, which is equipped with a flocculant outlet and a desalted water inlet. In mixing tank 8, the spent acid is mixed with the flocculant, and impurities such as the precipitate and flocs formed by the reaction are flocculated and precipitated through flocculation and precipitation.

[0029] The flocculated waste acid then enters the sedimentation tank 9 for sedimentation. The sedimentation tank 9 is equipped with a mixed liquid inlet, a purified waste acid outlet, and a sediment outlet. The mixed liquid inlet is connected to the mixing tank 8, the purified waste acid outlet is connected to the purified waste acid tank 13, and the sediment outlet is connected to the filter press 10. The filter press 10 is equipped with a filtrate outlet and a filter cake outlet, and the filtrate outlet is connected to the sedimentation tank 9. The purified waste acid formed by sedimentation in the sedimentation tank 9 is sent to the purified waste acid tank 13. The sediment then enters the filter press 10 for filtration. The filtrate returns to the sedimentation tank 9, and the filter cake is shipped out.

[0030] The purified waste acid tank 13 is provided with a purified waste acid inlet, a hydrochloric acid inlet, and a purified waste acid outlet. The purified waste acid outlet is connected to an evaporator 15 via a heat exchanger 14. The purified waste acid in the purified waste acid tank 13 then enters the evaporator 15 for OSLO energy-saving evaporation and recrystallization. The evaporator 15 is provided with a purified waste acid inlet, a steam inlet, and an outlet for ferrous chloride crystals. The outlet for ferrous chloride crystals is connected to a centrifugal separator 16. After evaporation and recrystallization, high-purity ferrous chloride is generated, and soluble impurity ions such as manganese, calcium, sodium, and magnesium are removed.

[0031] The high-purity ferrous chloride then enters the stirring and dissolving tank 17 for dissolution. The stirring and dissolving tank is provided with a ferrous chloride crystal inlet, a desalted water inlet and a ferrous chloride solution outlet. The ferrous chloride solution outlet is connected to the ferrous chloride storage tank 18. The stirring and dissolving tank prepares the high-purity ferrous chloride into a ferrous chloride solution of appropriate concentration and then performs acid regeneration.

[0032] Furthermore, a spray roasting device (not shown) is provided at the outlet end of the ferrous chloride storage tank 18, and the ferrous chloride storage tank 18 in the ferrous chloride storage tank 18 is spray roasted by the spray roasting device to produce high-purity iron oxide red.

[0033] The system of this embodiment removes most of the free hydrochloric acid in the waste acid through the neutralization tower 1, and produces ferric hydroxide through the reaction tank 4. The flocculent structure of the ferric hydroxide is used to adsorb acid-insoluble impurities such as silicon in the waste acid. At the same time, by adjusting the pH value, metal ions such as Cu and Al in the waste acid are formed into hydroxide precipitates. Then, a flocculant is added through the mixing tank 8, and the formed precipitates, floccules and other impurities are removed by flocculation and precipitation, thereby forming purified waste acid. In addition, the purified waste acid is evaporated and crystallized through the evaporator 15 to produce pure ferrous chloride crystals, thereby leaving soluble impurities such as manganese, calcium, sodium, and magnesium in the mother liquor. The ferrous chloride is dissolved by the stirring and dissolving tank 17 to produce a high-purity ferrous chloride solution. The high-purity ferrous chloride solution can produce a high-quality iron oxide red product that meets the standards through acid regeneration spray roasting. The system can adapt to the pickling of various steel grades in cold rolling pickling, which is beneficial to providing high-quality iron oxide red raw materials for the magnetic material industry.

[0034] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A system for producing high-purity ferrous chloride by desiliconization and purification of waste acid, characterized in that: The invention comprises a purification system and a purification system. The purification system comprises a neutralization tower, a reaction tank, a mixing tank, a sedimentation tank and a waste acid purification tank which are arranged in sequence. The purification system comprises an evaporator, a centrifugal separator, a stirring and dissolving tank and a ferrous chloride storage tank which are arranged in sequence. The inlet of the evaporator is connected to the outlet of the waste acid purification tank.

2. The system according to claim 1, wherein: The neutralization tower is provided with a waste acid inlet, a crushed steel bar inlet and a waste acid outlet. A heating heat exchanger for heating the waste acid is provided at the inlet end of the waste acid inlet, and an electromagnetic crane for lifting the crushed steel bars to the neutralization tower is provided at the inlet end of the crushed steel bar inlet.

3. The system according to claim 1, wherein: The reaction tank is provided with a waste acid inlet, an ammonia water inlet, a compressed air inlet and a waste acid outlet. A cooling heat exchanger for cooling the waste acid is provided at the inlet end of the waste acid inlet, and the ammonia water inlet is connected to the ammonia water tank.

4. The system according to claim 1, wherein: The mixing tank is provided with a flocculant inlet, a waste acid inlet and a waste acid outlet, and the flocculant inlet is communicated with the flocculant storage tank.

5. The system according to claim 4, characterized in that The flocculant storage tank is communicated with the flocculant dissolving tank, and the flocculant dissolving tank is provided with a flocculant outlet and a desalted water inlet.

6. The system according to claim 4, characterized in that The sedimentation tank is provided with a mixed liquor inlet, a purified waste acid outlet and a sediment outlet. The mixed liquor inlet is connected to the mixing tank, the purified waste acid outlet is connected to the purified waste acid tank, the sediment outlet is connected to the filter press, the filter press is provided with a filtrate outlet and a filter cake outlet, and the filtrate outlet is connected to the sedimentation tank.

7. The system according to claim 1, wherein: The purified waste acid tank is provided with a purified waste acid inlet, a hydrochloric acid inlet and a purified waste acid outlet, and the purified waste acid outlet is connected to the evaporator through a heat exchanger.

8. The system according to claim 1, wherein: The evaporator is provided with a purified waste acid inlet, a steam inlet and a ferrous chloride crystal outlet, and the ferrous chloride crystal outlet is connected to the centrifugal separator.

9. The system according to claim 1, wherein: The stirring dissolver is provided with a ferrous chloride crystal inlet, a desalted water inlet and a ferrous chloride solution outlet, and the ferrous chloride solution outlet is connected to a ferrous chloride storage tank.

10. The system according to claim 1, wherein: A spray roasting device is provided at the outlet end of the ferrous chloride storage tank.

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