CN114517261B - Method and device for selectively extracting and recovering chromium element in electroplating sludge - Google Patents
Method and device for selectively extracting and recovering chromium element in electroplating sludge Download PDFInfo
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- CN114517261B CN114517261B CN202111477425.8A CN202111477425A CN114517261B CN 114517261 B CN114517261 B CN 114517261B CN 202111477425 A CN202111477425 A CN 202111477425A CN 114517261 B CN114517261 B CN 114517261B
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
- C22B7/00—Working up raw materials other than ores, e.g. scrap, to produce non-ferrous metals and compounds thereof; Methods of a general interest or applied to the winning of more than two metals
- C22B7/006—Wet processes
- C22B7/007—Wet processes by acid leaching
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
- C22B1/00—Preliminary treatment of ores or scrap
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
- C22B34/00—Obtaining refractory metals
- C22B34/30—Obtaining chromium, molybdenum or tungsten
- C22B34/32—Obtaining chromium
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
- C22B7/00—Working up raw materials other than ores, e.g. scrap, to produce non-ferrous metals and compounds thereof; Methods of a general interest or applied to the winning of more than two metals
- C22B7/006—Wet processes
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Abstract
The invention discloses a method and a device for selectively extracting and recovering chromium elements in electroplating sludge, wherein the method comprises the following steps: s1, sequentially dehydrating, drying, roasting and crushing electroplating sludge to obtain sludge particles to be leached; s2, mixing sludge particles to be leached with sulfuric acid solution, heating, carrying out ultrasonic treatment, and then filtering; s3, adding an ethanol solution into the leaching solution treated in the step S2, uniformly mixing, and then carrying out gasification treatment to obtain gas-phase chromium element; finally, introducing gas-phase chromium element into ferrous sulfate heptahydrate solution to react to form trivalent chromium precipitate, and separating the trivalent chromium precipitate; the method has reasonable design and high recovery rate of chromium element in the electroplating sludge, realizes the recycling of the electroplating sludge, and has obvious economic and environmental benefits.
Description
Technical Field
The invention relates to the technical field of electroplating sludge treatment, in particular to a method and a device for selectively extracting and recovering chromium elements in electroplating sludge.
Background
The chromium element in the electroplating sludge is easily oxidized into soluble complex anions, and then is transferred into surface water or underground water through leaching. When the chromium in the soil is too much, the nitrification of organic substances can be inhibited, chromium is accumulated in plants, natural water generally contains only trace chromium, the natural water is conveyed into the sea through a river and is sunk on the sea floor, and when the contents of the organic substances in the underground water are accumulated to a certain degree, crops can stop growing and die.
Then, when separating and recovering metal elements in the electroplating sludge in the prior art, the electroplating sludge contains various heavy metal elements such as copper, zinc, nickel, chromium and the like due to high water content and complex components; the metal is usually in the states of hydroxide, oxide, carbonate and the like, and the fluctuation range of the metal content is large; thus, it is difficult to achieve selective extraction and recovery of chromium element.
Disclosure of Invention
Aiming at the technical problems, the invention provides a method and a device for selectively extracting and recovering chromium elements in electroplating sludge.
The technical scheme of the invention is as follows: a method for selectively extracting and recovering chromium elements in electroplating sludge comprises the following steps:
s1, pretreatment of electroplating sludge:
s1-1, introducing electroplating sludge into dehydration equipment, carrying out pressure maintaining dehydration treatment for 30-55 min under the pressure of 1.8-2.5 MPa, and drying until the water content is less than 20%, thereby obtaining dried sludge;
S1-2, placing the dried sludge obtained in the step S1-1 into a roasting furnace, roasting at 300-780 ℃ for 20-45 min in air atmosphere, naturally cooling, crushing, and sieving with a 20-50 mesh sieve to obtain sludge particles to be leached;
s2, acid leaching:
s2-1, preparing a sulfuric acid solution with the mass concentration of 5-11%, and then mixing the sulfuric acid solution with the sludge particles to be leached obtained in the step S1-2 according to the volume ratio of 5-8:1 to obtain a mixture A;
s2-2, heating the mixture A obtained in the step S2-1 to 30-90 ℃, and then carrying out ultrasonic treatment at a frequency of 22-35 kHz and a power of 630-880W for 20-60 min to obtain a mixture B; finally, filtering the mixture B to obtain filtrate;
s2-3, standing the filtrate obtained in the step S2-2 for 45-85 min, and extracting supernatant to obtain leaching liquid;
s3, enriching chromium:
s3-1, adding 5-13% ethanol solution into the leaching solution obtained in the step S2-3, stirring and mixing uniformly, and then introducing into a gasification box for gasification treatment at the temperature of 250-480 ℃ to obtain gas-phase chromium element;
s3-2, introducing the gas-phase chromium element obtained in the step S3-1 into a ferrous sulfate heptahydrate solution with the mass concentration of 15-23% to react for 30-55 min to form trivalent chromium precipitate, and separating the trivalent chromium precipitate.
Further, after the step S1-2 is completed, the sludge particles to be leached are put into a desiccator, and are desiccated for 25-45 min at the temperature of 880-1050 ℃; by drying the sludge particles to be leached, organic matters and combustible impurities in the sludge particles to be leached can be effectively removed, the separation difficulty of chromium elements in electroplating sludge is reduced, and the extraction efficiency of the chromium elements is improved.
Further, after the step S3-2 is completed, firstly, the ion exchange resin is utilized to carry out adsorption treatment on the ferrous sulfate heptahydrate solution, then, the sodium carbonate aqueous solution with the mass concentration of 12-18% is utilized to carry out desorption on the ion exchange resin, and the sediment in the desorption liquid is separated; the ion exchange resin adsorption treatment is carried out on the ferrous sulfate heptahydrate solution, so that suspended chromium element in the ferrous sulfate heptahydrate solution can be effectively extracted.
Further, after the step S2-3 is completed, introducing the leaching solution into a high-pressure reaction kettle, controlling the temperature of the high-pressure reaction kettle to be 280-350 ℃ and the pressure to be 3-6 MPa, and continuously reacting for 10-25 min, and discharging the high-pressure reaction kettle to obtain hot-water leaching solution; by carrying out hydrothermal treatment on the leaching solution, viscous organic matters in the leaching solution can be decomposed, and meanwhile, the colloid structure in the leaching solution can be destroyed, so that the enrichment efficiency of chromium element is improved.
Further, after the step S3-2 is completed, trivalent chromium precipitate is dried to constant weight at the temperature of 90-120 ℃, and then is ball-milled into particles with the particle size of less than 2 mm; the trivalent chromium precipitate is dried and ball-milled, so that the collection and the utilization of chromium materials are facilitated.
Further, after the step S2-1 is completed, 5 to 11 percent of hydrogen peroxide solution with the volume concentration of 4 to 9 percent is added into the mixture A, and the mixture A reacts for 45 to 60 minutes at the temperature of 125 to 185 ℃; by adding the hydrogen peroxide solution into the mixture A, the conversion efficiency of hexavalent chromium in the mixture A can be improved, new metal ions can not be introduced, and the extraction efficiency of chromium element in electroplating sludge is improved.
The invention also provides a device for selectively extracting and recycling chromium elements in the electroplating sludge, which comprises dehydration equipment for deep dehydration of the electroplating sludge, a roasting furnace for roasting the dried sludge, and a gasification box for gasification treatment of a mixed solution of leaching liquid and ethanol solution, wherein the dehydration equipment comprises an outer shell, a lifting assembly, an extrusion dehydration assembly and a controller; the lower end of the outer shell is provided with a water collecting tank which is communicated with the inside of the outer shell, and the side wall of the water collecting tank is provided with a drain pipe;
The lifting assembly comprises lifting sleeves and lifting motors, the lifting sleeves are movably sleeved in the outer shell, the first connecting sleeves are rotatably clamped at the lower positions outside the lifting sleeves and fixedly connected with the inner wall of the outer shell, the two lifting motors are symmetrically arranged at two sides of the inner side of the outer shell through mounting rings and are positioned at the upper ends of the first connecting sleeves, lifting screw rods are arranged on output shafts of the lifting motors, and the two lifting screw rods penetrate through the mounting rings respectively and are in threaded connection with the first connecting sleeves respectively;
the extrusion dehydration assembly comprises a dehydration barrel, an extrusion motor, an extrusion plate and a driving motor, wherein the dehydration barrel is sleeved inside a lifting sleeve, the upper end of the dehydration barrel is provided with an opening, the lower end of the dehydration barrel is clamped with a movable plate, a plurality of water outlet holes are formed in the side wall in a penetrating manner, two second connecting sleeves are rotatably clamped on the side wall of the dehydration barrel, the two second connecting sleeves are fixedly connected with the inner wall of the lifting sleeve respectively, the extrusion plate is slidably clamped at the opening at the upper end of the dehydration barrel, the extrusion motor is arranged at the top of an outer shell, an extrusion screw is arranged on an output shaft of the extrusion motor, and is rotatably clamped with the inner bottom of the dehydration barrel after penetrating through the extrusion plate, and the extrusion screw is in threaded connection with the extrusion plate; the movable plate is connected with the top of the water collection tank through a shaft rod, a connecting gear is sleeved on the shaft rod, a driving motor is arranged at the top of the water collection tank, and a driving gear meshed with the connecting gear is arranged on an output shaft of the driving motor;
The controller is respectively and electrically connected with the lifting motor, the extrusion motor and the driving motor.
Further, a vibrating plate is connected to the extruding plate in a sliding clamping mode, a curved vibrating sleeve is arranged on the upper end face of the vibrating plate, a mounting plate is sleeved on the extruding screw rod, an extruding roller is connected to the lower end of the mounting plate in a rotating clamping mode, and the extruding roller is in butt joint with the upper end face of the curved vibrating sleeve; the vibrating plate is provided with the slide bar with the stripper plate junction, and the cover is equipped with reset spring on the slide bar, reset spring upper end and vibrating plate butt, lower extreme and stripper plate butt, and extrusion lead screw rotates the in-process, drives mounting panel and extrusion gyro wheel and rotates to make the vibrating plate reciprocating motion from top to bottom under the effect of extrusion gyro wheel, realize electroplating sludge's vibration extrusion dehydration, be favorable to improving electroplating sludge's dehydration efficiency.
Further, be provided with the guide bar on the collar, guide bar and lifting sleeve's outer wall slip joint is favorable to improving lifting sleeve's stability when removing through setting up the guide bar to improve whole dewatering device's operating stability.
Further, the header tank upper end is provided with the lag, and the lag upper end rotates the joint with the fly leaf lower terminal surface, and driving motor is located the lag inside, through setting up the lag, can avoid mud to produce the influence to connecting gear and drive gear's meshing effect.
The working principle of the dehydration equipment of the invention is as follows:
s1, respectively connecting a lifting motor, an extrusion motor and a driving motor with an external power supply, and controlling the extrusion motor to reversely rotate through a controller so that the extrusion plate moves upwards along the dehydration barrel;
s2, placing the electroplating sludge into a dehydration barrel, controlling the extrusion motor to rotate forwards through a controller, enabling the extrusion plate to move downwards along the dehydration barrel under the action of an extrusion screw rod, and performing extrusion dehydration treatment on the electroplating sludge; meanwhile, in the rotation process of the extrusion screw, the mounting plate and the extrusion roller are driven to rotate, so that the vibration plate reciprocates up and down under the combined action of the extrusion roller and the surface vibration sleeve, and vibration extrusion dehydration of electroplating sludge is realized; the sewage removed from the electroplating sludge enters the water collecting tank through the water outlet hole and is collected by the drain pipe;
s3, after the extrusion and dehydration of the electroplating sludge are completed, the driving motor is controlled by the controller to drive, and the driving gear is meshed with the connecting gear, so that the movable plate drives the dehydration cylinder to rotate, and the centrifugal dehydration of the electroplating sludge is realized;
s4, after the centrifugal dehydration of the electroplating sludge is completed, the extrusion motor is controlled to reversely rotate by the controller, the extrusion plate moves upwards along the dehydration barrel, the lifting motor is controlled to be started by the controller, the lifting sleeve moves upwards along the guide rod under the action of the lifting screw rod, the dehydration barrel simultaneously moves upwards under the driving action of the lifting sleeve and is separated from the movable plate, and finally the dehydrated electroplating sludge is removed.
Compared with the prior art, the invention has the beneficial effects that: the method has reasonable design, can realize the selective recovery of chromium in the electroplating sludge, can obviously improve the recovery efficiency of the chromium, and is beneficial to promoting the conversion of the chromium into chromium metal products, thereby realizing the recycling of the electroplating sludge and having obvious economic and environmental benefits; according to the chemical characteristics of chromium, sulfuric acid solution is used as leaching solution of chromium; meanwhile, in the chromium element leaching process, the influence of colloid in the solution on the leaching of the chromium element can be effectively avoided by utilizing an ultrasonic means, and the leaching efficiency of the chromium element is further improved; before leaching chromium element in the electroplating sludge, roasting the electroplating sludge, so that the electroplating sludge is prevented from hardening after dehydration and drying, and the chromium element in the electroplating sludge is promoted to be oxidized by contacting with outside air; the dewatering equipment can realize extrusion, vibration and centrifugal dewatering treatment of the electroplating sludge, effectively improve the dewatering efficiency of the electroplating sludge, avoid interference of organic matters in the electroplating sludge on leaching of chromium elements, simultaneously destroy complexation of organic matters such as proteins on chromium, and improve the recovery efficiency of the chromium elements in the electroplating sludge.
Drawings
FIG. 1 is a longitudinal cross-sectional view of the dewatering apparatus of the present invention;
FIG. 2 is a left side view of the dehydration engine of the present invention;
FIG. 3 is a schematic view showing the internal structure of the dehydrating apparatus of the present invention;
FIG. 4 is a schematic structural view of the dewatering cartridge of the present invention;
FIG. 5 is a schematic diagram of the connection of the movable plate and the dewatering drum of the present invention;
FIG. 6 is an enlarged schematic view of the invention at A in FIG. 1;
the device comprises a 1-outer shell, a 10-water collecting tank, a 11-drain pipe, a 12-protective sleeve, a 2-lifting assembly, a 20-lifting sleeve, a 200-first connecting sleeve, a 21-lifting motor, a 210-mounting ring, a 2100-guide rod, a 211-lifting screw rod, a 3-extrusion dehydration assembly, a 30-dehydration cylinder, a 300-water outlet hole, a 301-second connecting sleeve, a 31-extrusion motor, a 310-extrusion screw rod, a 311-mounting plate, a 312-extrusion roller, a 32-extrusion plate, a 320-vibration plate, a 3200-sliding rod, a 3201-reset spring, a 321-curved-surface vibration sleeve, a 33-movable plate, a 330-shaft rod, a 331-connecting gear, a 34-driving motor and a 340-driving gear.
Detailed Description
Example 1
A method for selectively extracting and recovering chromium elements in electroplating sludge comprises the following steps:
s1, pretreatment of electroplating sludge:
s1-1, introducing electroplating sludge into dehydration equipment, carrying out pressure maintaining dehydration treatment for 30min under the pressure of 1.8MPa, and drying until the water content reaches 15%, thereby obtaining dried sludge;
S1-2, placing the dried sludge obtained in the step S1-1 into a roasting furnace, roasting at 300 ℃ for 20min in an air atmosphere, naturally cooling, crushing, and sieving with a 20-mesh sieve to obtain sludge particles to be leached;
s2, acid leaching:
s2-1, preparing a sulfuric acid solution with the mass concentration of 5%, and then mixing the sulfuric acid solution with the sludge particles to be leached obtained in the step S1-2 according to the volume ratio of 5:1 to obtain a mixture A;
s2-2, heating the mixture A obtained in the step S2-1 to 30 ℃, and then carrying out ultrasonic treatment at a frequency of 22kHz and a power of 630W for 20min to obtain a mixture B; finally, filtering the mixture B to obtain filtrate;
s2-3, standing the filtrate obtained in the step S2-2 for 45min, and then extracting supernatant to obtain leaching liquid;
s3, enriching chromium:
s3-1, adding ethanol solution with the concentration of 5% into the leaching solution obtained in the step S2-3, stirring and mixing uniformly, and then introducing into a gasification box for gasification treatment at the temperature of 250 ℃ to obtain gas-phase chromium element;
s3-2, introducing the gas-phase chromium element obtained in the step S3-1 into a ferrous sulfate heptahydrate solution with the mass concentration of 15% for reaction for 30min to form trivalent chromium precipitate, and separating the trivalent chromium precipitate.
Example 2
The embodiment describes a chromium element selective extraction and recovery device suitable for the electroplating sludge of the embodiment 1, which comprises a dehydration device for deep dehydration of the electroplating sludge, a roasting furnace for roasting the dried sludge, and a gasification box for gasification treatment of a mixed solution of leaching liquid and ethanol solution, wherein the dehydration device comprises an outer shell 1, a lifting assembly 2, an extrusion dehydration assembly 3 and a controller; the lower end of the outer shell 1 is provided with a water collecting tank 10, the water collecting tank 10 is communicated with the inside of the outer shell 1, and the side wall of the water collecting tank 10 is provided with a drain pipe 11;
the lifting assembly 2 comprises a lifting sleeve 20 and lifting motors 21, wherein the lifting sleeve 20 is movably sleeved inside the outer shell 1, a first connecting sleeve 200 is rotatably clamped at the lower position outside the lifting sleeve 20, the first connecting sleeve 200 is fixedly connected with the inner wall of the outer shell 1, two lifting motors 21 are symmetrically arranged at two sides inside the outer shell 1 through mounting rings 210 and are positioned at the upper end of the first connecting sleeve 200, lifting lead screws 211 are arranged on output shafts of the lifting motors 21, and the two lifting lead screws 211 respectively penetrate through the mounting rings 210 and are respectively in threaded connection with the first connecting sleeve 200;
The extrusion dehydration assembly 3 comprises a dehydration barrel 30, an extrusion motor 31, an extrusion plate 32 and a driving motor 34, wherein the dehydration barrel 30 is sleeved inside the lifting sleeve 20, the upper end of the dehydration barrel 30 is provided with an opening, the lower end of the dehydration barrel is provided with a movable plate 33 in a clamping manner, a plurality of water outlet holes 300 are formed in the side wall in a penetrating manner, two second connecting sleeves 301 are rotatably clamped on the side wall of the dehydration barrel 30, the two second connecting sleeves 301 are fixedly connected with the inner wall of the lifting sleeve 20 respectively, the extrusion plate 32 is slidably clamped at the opening at the upper end of the dehydration barrel 30, the extrusion motor 31 is arranged at the top of the outer shell 1, an extrusion screw 310 is arranged on an output shaft of the extrusion motor 31, and the extrusion screw 310 is rotatably clamped with the inner bottom of the dehydration barrel 30 after penetrating through the extrusion plate 32, and is in threaded connection with the extrusion plate 32; the movable plate 33 is connected with the top of the water collection tank 10 through a shaft rod 330, a connecting gear 331 is sleeved on the shaft rod 330, a driving motor 34 is arranged on the top of the water collection tank 10, and a driving gear 340 meshed with the connecting gear 331 is arranged on an output shaft of the driving motor 34;
the controller is respectively and electrically connected with the lifting motor 21, the extrusion motor 31 and the driving motor 34; the controller, the lift motor 21, the pressing motor 31, and the driving motor 34 are all commercially available products.
Example 3
A method for selectively extracting and recovering chromium elements in electroplating sludge comprises the following steps:
s1, pretreatment of electroplating sludge:
s1-1, introducing electroplating sludge into dehydration equipment, carrying out pressure maintaining dehydration treatment under the pressure of 2.1MPa for 40min, and drying until the water content reaches 16%, thereby obtaining dried sludge;
s1-2, placing the dried sludge obtained in the step S1-1 into a roasting furnace, roasting at 480 ℃ for 36min in an air atmosphere, naturally cooling, crushing, and sieving with a 45-mesh sieve to obtain sludge particles to be leached; placing sludge particles to be leached into a desiccator, and drying at 880 ℃ for 25min; the sludge particles to be leached are subjected to drying treatment, so that organic matters and combustible impurities in the sludge particles to be leached can be effectively removed, the separation difficulty of chromium elements in electroplating sludge is reduced, and the extraction efficiency of the chromium elements is improved;
s2, acid leaching:
s2-1, preparing a sulfuric acid solution with the mass concentration of 9%, and then mixing the sulfuric acid solution with the dried sludge particles to be leached obtained in the step S1-2 according to the volume ratio of 7:1 to obtain a mixture A;
s2-2, heating the mixture A obtained in the step S2-1 to 65 ℃, and then carrying out ultrasonic treatment at a frequency of 28kHz and a power of 725W for 40min to obtain a mixture B; finally, filtering the mixture B to obtain filtrate;
S2-3, standing the filtrate obtained in the step S2-2 for 68min, and extracting supernatant to obtain a leaching solution;
s3, enriching chromium:
s3-1, adding an ethanol solution with the volume of 9% into the leaching solution obtained in the step S2-3, stirring and mixing uniformly, and then introducing into a gasification box for gasification treatment at the temperature of 360 ℃ to obtain gas-phase chromium element;
s3-2, introducing the gas-phase chromium element obtained in the step S3-1 into a ferrous sulfate heptahydrate solution with the mass concentration of 19% for reaction for 42min to form trivalent chromium precipitate, and separating the trivalent chromium precipitate.
Example 4
The embodiment describes a chromium element selective extraction and recovery device applicable to the electroplating sludge of the embodiment 3, which comprises a dehydration device for deep dehydration of the electroplating sludge, a roasting furnace for roasting the dry sludge, and a gasification box for gasification treatment of a mixed solution of leaching liquid and ethanol solution, wherein the dehydration device comprises an outer shell 1, a lifting assembly 2, an extrusion dehydration assembly 3 and a controller; the lower end of the outer shell 1 is provided with a water collecting tank 10, the water collecting tank 10 is communicated with the inside of the outer shell 1, and the side wall of the water collecting tank 10 is provided with a drain pipe 11;
the lifting assembly 2 comprises a lifting sleeve 20 and lifting motors 21, wherein the lifting sleeve 20 is movably sleeved inside the outer shell 1, a first connecting sleeve 200 is rotatably clamped at the lower position outside the lifting sleeve 20, the first connecting sleeve 200 is fixedly connected with the inner wall of the outer shell 1, two lifting motors 21 are symmetrically arranged at two sides inside the outer shell 1 through mounting rings 210 and are positioned at the upper end of the first connecting sleeve 200, lifting lead screws 211 are arranged on output shafts of the lifting motors 21, and the two lifting lead screws 211 respectively penetrate through the mounting rings 210 and are respectively in threaded connection with the first connecting sleeve 200;
The extrusion dehydration assembly 3 comprises a dehydration barrel 30, an extrusion motor 31, an extrusion plate 32 and a driving motor 34, wherein the dehydration barrel 30 is sleeved inside the lifting sleeve 20, the upper end of the dehydration barrel 30 is opened, the lower end of the dehydration barrel is clamped with a movable plate 33, a plurality of water outlet holes 300 are formed in the side wall in a penetrating manner, two second connecting sleeves 301 are rotatably clamped on the side wall of the dehydration barrel 30, the two second connecting sleeves 301 are fixedly connected with the inner wall of the lifting sleeve 20 respectively, the extrusion plate 32 is slidably clamped at the opening of the upper end of the dehydration barrel 30, a vibration plate 320 is slidably clamped on the extrusion plate 32, a curved vibration sleeve 321 is arranged on the upper end face of the vibration plate 320, a mounting plate 311 is sleeved on the extrusion screw 310, extrusion rollers 312 are rotatably clamped at the lower end of the mounting plate 311, and the extrusion rollers 312 are abutted with the upper end face of the curved vibration sleeve 321; a sliding rod 3200 is arranged at the joint of the vibration plate 320 and the extrusion plate 32, a reset spring 3201 is sleeved on the sliding rod 3200, the upper end of the reset spring 3201 is in butt joint with the vibration plate 320, the lower end of the reset spring is in butt joint with the extrusion plate 32, and in the rotation process of the extrusion screw 310, the mounting plate 311 and the extrusion roller 312 are driven to rotate, so that the vibration plate 320 reciprocates up and down under the action of the extrusion roller 312, vibration extrusion dehydration of electroplating sludge is realized, and the dehydration efficiency of the electroplating sludge is improved; the extrusion motor 31 is arranged at the top of the outer shell 1, an extrusion screw 310 is arranged on an output shaft of the extrusion motor 31, the extrusion screw 310 penetrates through the extrusion plate 32 and is rotationally clamped with the inner bottom of the dehydration barrel 30, and the extrusion screw 310 is in threaded connection with the extrusion plate 32; the movable plate 33 is connected with the top of the water collection tank 10 through a shaft rod 330, a connecting gear 331 is sleeved on the shaft rod 330, a driving motor 34 is arranged on the top of the water collection tank 10, and a driving gear 340 meshed with the connecting gear 331 is arranged on an output shaft of the driving motor 34;
The controller is respectively and electrically connected with the lifting motor 21, the extrusion motor 31 and the driving motor 34; the controller, the lift motor 21, the pressing motor 31, and the driving motor 34 are all commercially available products.
Example 5
A method for selectively extracting and recovering chromium elements in electroplating sludge comprises the following steps:
s1, pretreatment of electroplating sludge:
s1-1, introducing electroplating sludge into dehydration equipment, carrying out pressure maintaining dehydration treatment under the pressure of 2.5MPa for 55min, and drying until the water content reaches 14%, thereby obtaining dried sludge;
s1-2, placing the dried sludge obtained in the step S1-1 into a roasting furnace, roasting at 780 ℃ for 45min in an air atmosphere, naturally cooling, crushing, and sieving with a 50-mesh sieve to obtain sludge particles to be leached;
s2, acid leaching:
s2-1, preparing a sulfuric acid solution with the mass concentration of 11%, and then mixing the sulfuric acid solution with the sludge particles to be leached obtained in the step S1-2 according to the volume ratio of 8:1 to obtain a mixture A;
s2-2, heating the mixture A obtained in the step S2-1 to 90 ℃, and then carrying out ultrasonic treatment at a frequency of 35kHz and a power of 880W for 60min to obtain a mixture B; finally, filtering the mixture B to obtain filtrate;
s2-3, standing the filtrate obtained in the step S2-2 for 85min, and then extracting supernatant to obtain leaching liquid;
S3, enriching chromium:
s3-1, adding 13% ethanol solution into the leaching solution obtained in the step S2-3, stirring and mixing uniformly, and then introducing into a gasification box for gasification treatment at 480 ℃ to obtain gas-phase chromium element;
s3-2, introducing the gas-phase chromium element obtained in the step S3-1 into a ferrous sulfate heptahydrate solution with the mass concentration of 23% for reaction for 55min to form trivalent chromium precipitate, and separating the trivalent chromium precipitate; firstly, carrying out adsorption treatment on a ferrous sulfate heptahydrate solution by utilizing ion exchange resin, then desorbing the ion exchange resin by utilizing sodium carbonate aqueous solution with the mass concentration of 12%, and separating sediment in desorption liquid; the ion exchange resin adsorption treatment is carried out on the ferrous sulfate heptahydrate solution, so that suspended chromium element in the ferrous sulfate heptahydrate solution can be effectively extracted; drying trivalent chromium precipitate at 90deg.C to constant weight, and ball grinding into granule with particle diameter of 0.5-1.5 mm; the trivalent chromium precipitate is dried and ball-milled, so that the collection and the utilization of chromium materials are facilitated.
Example 6
The embodiment describes a chromium element selective extraction and recovery device applicable to the electroplating sludge of the embodiment 5, which comprises a dehydration device for deep dehydration of the electroplating sludge, a roasting furnace for roasting the dry sludge, and a gasification box for gasification treatment of a mixed solution of leaching liquid and ethanol solution, wherein the dehydration device comprises an outer shell 1, a lifting assembly 2, an extrusion dehydration assembly 3 and a controller; the lower end of the outer shell 1 is provided with a water collecting tank 10, the water collecting tank 10 is communicated with the inside of the outer shell 1, and the side wall of the water collecting tank 10 is provided with a drain pipe 11;
The lifting assembly 2 comprises a lifting sleeve 20 and lifting motors 21, wherein the lifting sleeve 20 is movably sleeved inside the outer shell 1, a first connecting sleeve 200 is rotatably clamped at the lower position outside the lifting sleeve 20, the first connecting sleeve 200 is fixedly connected with the inner wall of the outer shell 1, two lifting motors 21 are symmetrically arranged at two sides inside the outer shell 1 through mounting rings 210 and are positioned at the upper end of the first connecting sleeve 200, lifting lead screws 211 are arranged on output shafts of the lifting motors 21, and the two lifting lead screws 211 respectively penetrate through the mounting rings 210 and are respectively in threaded connection with the first connecting sleeve 200; the guide rod 2100 is arranged on the mounting ring 210 and is in sliding clamping connection with the outer wall of the lifting sleeve 20, and the stability of the lifting sleeve 20 during movement is improved by arranging the guide rod 2100, so that the running stability of the whole dewatering device is improved;
the extrusion dehydration assembly 3 comprises a dehydration barrel 30, an extrusion motor 31, an extrusion plate 32 and a driving motor 34, wherein the dehydration barrel 30 is sleeved inside the lifting sleeve 20, the upper end of the dehydration barrel 30 is opened, the lower end of the dehydration barrel is clamped with a movable plate 33, a plurality of water outlet holes 300 are formed in the side wall in a penetrating manner, two second connecting sleeves 301 are rotatably clamped on the side wall of the dehydration barrel 30, the two second connecting sleeves 301 are fixedly connected with the inner wall of the lifting sleeve 20 respectively, the extrusion plate 32 is slidably clamped at the opening of the upper end of the dehydration barrel 30, a vibration plate 320 is slidably clamped on the extrusion plate 32, a curved vibration sleeve 321 is arranged on the upper end face of the vibration plate 320, a mounting plate 311 is sleeved on the extrusion screw 310, extrusion rollers 312 are rotatably clamped at the lower end of the mounting plate 311, and the extrusion rollers 312 are abutted with the upper end face of the curved vibration sleeve 321; a sliding rod 3200 is arranged at the joint of the vibration plate 320 and the extrusion plate 32, a reset spring 3201 is sleeved on the sliding rod 3200, the upper end of the reset spring 3201 is in butt joint with the vibration plate 320, the lower end of the reset spring is in butt joint with the extrusion plate 32, and in the rotation process of the extrusion screw 310, the mounting plate 311 and the extrusion roller 312 are driven to rotate, so that the vibration plate 320 reciprocates up and down under the action of the extrusion roller 312, vibration extrusion dehydration of electroplating sludge is realized, and the dehydration efficiency of the electroplating sludge is improved; the extrusion motor 31 is arranged at the top of the outer shell 1, an extrusion screw 310 is arranged on an output shaft of the extrusion motor 31, the extrusion screw 310 penetrates through the extrusion plate 32 and is rotationally clamped with the inner bottom of the dehydration barrel 30, and the extrusion screw 310 is in threaded connection with the extrusion plate 32; the movable plate 33 is connected with the top of the water collection tank 10 through a shaft rod 330, a connecting gear 331 is sleeved on the shaft rod 330, a driving motor 34 is arranged on the top of the water collection tank 10, and a driving gear 340 meshed with the connecting gear 331 is arranged on an output shaft of the driving motor 34; the upper end of the water collection tank 10 is provided with the protective sleeve 12, the upper end of the protective sleeve 12 is rotationally clamped with the lower end surface of the movable plate 33, the driving motor 34 is positioned in the protective sleeve 12, and the protective sleeve 12 is arranged, so that the influence of sludge on the meshing effect of the connecting gear 331 and the driving gear 340 can be avoided;
The controller is respectively and electrically connected with the lifting motor 21, the extrusion motor 31 and the driving motor 34; the controller, the lift motor 21, the pressing motor 31, and the driving motor 34 are all commercially available products.
Example 7
A method for selectively extracting and recovering chromium elements in electroplating sludge comprises the following steps:
s1, pretreatment of electroplating sludge:
s1-1, introducing electroplating sludge into dehydration equipment, carrying out pressure maintaining dehydration treatment for 30min under the pressure of 1.8MPa, and drying until the water content reaches 16%, thereby obtaining dried sludge;
s1-2, placing the dried sludge obtained in the step S1-1 into a roasting furnace, roasting at 780 ℃ for 20min in an air atmosphere, naturally cooling, crushing, and sieving with a 20-mesh sieve to obtain sludge particles to be leached;
s2, acid leaching:
s2-1, preparing a sulfuric acid solution with the mass concentration of 5%, and then mixing the sulfuric acid solution with the sludge particles to be leached obtained in the step S1-2 according to the volume ratio of 5:1 to obtain a mixture A;
s2-2, heating the mixture A obtained in the step S2-1 to 30 ℃, and then carrying out ultrasonic treatment at a frequency of 22kHz and a power of 630W for 20min to obtain a mixture B; finally, filtering the mixture B to obtain filtrate;
s2-3, standing the filtrate obtained in the step S2-2 for 45min, and then extracting supernatant to obtain leaching liquid; introducing the leaching solution into a high-pressure reaction kettle, controlling the temperature of the high-pressure reaction kettle to be 280 ℃, controlling the pressure to be 3MPa, and continuously reacting for 10min, and discharging the high-pressure reaction kettle to obtain hot-water leaching solution; the leaching solution is subjected to hydrothermal treatment, so that viscous organic matters in the leaching solution can be decomposed, and meanwhile, the colloid structure in the leaching solution can be destroyed, and the enrichment efficiency of chromium element is improved;
S3, enriching chromium:
s3-1, adding an ethanol solution with the concentration of 5% into the hot water leaching solution obtained in the step S2-3, stirring and mixing uniformly, and then introducing into a gasification box for gasification treatment at the temperature of 250 ℃ to obtain gas-phase chromium element;
s3-2, introducing the gas-phase chromium element obtained in the step S3-1 into a ferrous sulfate heptahydrate solution with the mass concentration of 15% for reaction for 30min to form trivalent chromium precipitate, and separating the trivalent chromium precipitate.
Example 8
The embodiment describes a chromium element selective extraction and recovery device applicable to the electroplating sludge of the embodiment 7, which comprises a dehydration device for deep dehydration of the electroplating sludge, a roasting furnace for roasting the dry sludge, and a gasification box for gasification treatment of a mixed solution of leaching liquid and ethanol solution, wherein the dehydration device comprises an outer shell 1, a lifting assembly 2, an extrusion dehydration assembly 3 and a controller; the lower end of the outer shell 1 is provided with a water collecting tank 10, the water collecting tank 10 is communicated with the inside of the outer shell 1, and the side wall of the water collecting tank 10 is provided with a drain pipe 11;
the lifting assembly 2 comprises a lifting sleeve 20 and lifting motors 21, wherein the lifting sleeve 20 is movably sleeved inside the outer shell 1, a first connecting sleeve 200 is rotatably clamped at the lower position outside the lifting sleeve 20, the first connecting sleeve 200 is fixedly connected with the inner wall of the outer shell 1, two lifting motors 21 are symmetrically arranged at two sides inside the outer shell 1 through mounting rings 210 and are positioned at the upper end of the first connecting sleeve 200, lifting lead screws 211 are arranged on output shafts of the lifting motors 21, and the two lifting lead screws 211 respectively penetrate through the mounting rings 210 and are respectively in threaded connection with the first connecting sleeve 200; the guide rod 2100 is arranged on the mounting ring 210 and is in sliding clamping connection with the outer wall of the lifting sleeve 20, and the stability of the lifting sleeve 20 during movement is improved by arranging the guide rod 2100, so that the running stability of the whole dewatering device is improved;
The extrusion dehydration assembly 3 comprises a dehydration barrel 30, an extrusion motor 31, an extrusion plate 32 and a driving motor 34, wherein the dehydration barrel 30 is sleeved inside the lifting sleeve 20, the upper end of the dehydration barrel 30 is opened, the lower end of the dehydration barrel is clamped with a movable plate 33, a plurality of water outlet holes 300 are formed in the side wall in a penetrating manner, two second connecting sleeves 301 are rotatably clamped on the side wall of the dehydration barrel 30, the two second connecting sleeves 301 are fixedly connected with the inner wall of the lifting sleeve 20 respectively, the extrusion plate 32 is slidably clamped at the opening of the upper end of the dehydration barrel 30, a vibration plate 320 is slidably clamped on the extrusion plate 32, a curved vibration sleeve 321 is arranged on the upper end face of the vibration plate 320, a mounting plate 311 is sleeved on the extrusion screw 310, extrusion rollers 312 are rotatably clamped at the lower end of the mounting plate 311, and the extrusion rollers 312 are abutted with the upper end face of the curved vibration sleeve 321; a sliding rod 3200 is arranged at the joint of the vibration plate 320 and the extrusion plate 32, a reset spring 3201 is sleeved on the sliding rod 3200, the upper end of the reset spring 3201 is in butt joint with the vibration plate 320, the lower end of the reset spring is in butt joint with the extrusion plate 32, and in the rotation process of the extrusion screw 310, the mounting plate 311 and the extrusion roller 312 are driven to rotate, so that the vibration plate 320 reciprocates up and down under the action of the extrusion roller 312, vibration extrusion dehydration of electroplating sludge is realized, and the dehydration efficiency of the electroplating sludge is improved; the extrusion motor 31 is arranged at the top of the outer shell 1, an extrusion screw 310 is arranged on an output shaft of the extrusion motor 31, the extrusion screw 310 penetrates through the extrusion plate 32 and is rotationally clamped with the inner bottom of the dehydration barrel 30, and the extrusion screw 310 is in threaded connection with the extrusion plate 32; the movable plate 33 is connected with the top of the water collection tank 10 through a shaft rod 330, a connecting gear 331 is sleeved on the shaft rod 330, a driving motor 34 is arranged on the top of the water collection tank 10, and a driving gear 340 meshed with the connecting gear 331 is arranged on an output shaft of the driving motor 34; the upper end of the water collection tank 10 is provided with the protective sleeve 12, the upper end of the protective sleeve 12 is rotationally clamped with the lower end surface of the movable plate 33, the driving motor 34 is positioned in the protective sleeve 12, and the protective sleeve 12 is arranged, so that the influence of sludge on the meshing effect of the connecting gear 331 and the driving gear 340 can be avoided;
The controller is respectively and electrically connected with the lifting motor 21, the extrusion motor 31 and the driving motor 34; the controller, the lift motor 21, the pressing motor 31, and the driving motor 34 are all commercially available products.
Example 9: a method for selectively extracting and recovering chromium elements in electroplating sludge comprises the following steps:
s1, pretreatment of electroplating sludge:
s1-1, introducing electroplating sludge into dehydration equipment, carrying out pressure maintaining dehydration treatment under the pressure of 2.5MPa for 55min, and drying until the water content reaches 15%, thereby obtaining dried sludge;
s1-2, placing the dried sludge obtained in the step S1-1 into a roasting furnace, roasting at 780 ℃ for 45min in an air atmosphere, naturally cooling, crushing, and sieving with a 50-mesh sieve to obtain sludge particles to be leached;
s2, acid leaching:
s2-1, preparing a sulfuric acid solution with the mass concentration of 11%, and then mixing the sulfuric acid solution with the sludge particles to be leached obtained in the step S1-2 according to the volume ratio of 8:1 to obtain a mixture A; adding 5% by volume of hydrogen peroxide solution with the volume concentration of 4% into the mixture A, and reacting for 45min at the temperature of 125 ℃; by adding the hydrogen peroxide solution into the mixture A, the conversion efficiency of hexavalent chromium in the mixture A can be improved, new metal ions can not be introduced, and the extraction efficiency of chromium element in electroplating sludge is improved.
S2-2, heating the mixture A processed in the step S2-1 to 90 ℃, and then carrying out ultrasonic treatment at a frequency of 35kHz and a power of 880W for 60min to obtain a mixture B; finally, filtering the mixture B to obtain filtrate;
s2-3, standing the filtrate obtained in the step S2-2 for 85min, and then extracting supernatant to obtain leaching liquid;
s3, enriching chromium:
s3-1, adding 13% ethanol solution into the leaching solution obtained in the step S2-3, stirring and mixing uniformly, and then introducing into a gasification box for gasification treatment at 480 ℃ to obtain gas-phase chromium element;
s3-2, introducing the gas-phase chromium element obtained in the step S3-1 into a ferrous sulfate heptahydrate solution with the mass concentration of 23% for reaction for 55min to form trivalent chromium precipitate, and separating the trivalent chromium precipitate.
Example 10
The embodiment describes a chromium element selective extraction and recovery device applicable to the electroplating sludge of the embodiment 9, which comprises a dehydration device for deep dehydration of the electroplating sludge, a roasting furnace for roasting the dry sludge, and a gasification box for gasification treatment of a mixed solution of leaching liquid and ethanol solution, wherein the dehydration device comprises an outer shell 1, a lifting assembly 2, an extrusion dehydration assembly 3 and a controller; the lower end of the outer shell 1 is provided with a water collecting tank 10, the water collecting tank 10 is communicated with the inside of the outer shell 1, and the side wall of the water collecting tank 10 is provided with a drain pipe 11;
The lifting assembly 2 comprises a lifting sleeve 20 and lifting motors 21, wherein the lifting sleeve 20 is movably sleeved inside the outer shell 1, a first connecting sleeve 200 is rotatably clamped at the lower position outside the lifting sleeve 20, the first connecting sleeve 200 is fixedly connected with the inner wall of the outer shell 1, two lifting motors 21 are symmetrically arranged at two sides inside the outer shell 1 through mounting rings 210 and are positioned at the upper end of the first connecting sleeve 200, lifting lead screws 211 are arranged on output shafts of the lifting motors 21, and the two lifting lead screws 211 respectively penetrate through the mounting rings 210 and are respectively in threaded connection with the first connecting sleeve 200; the guide rod 2100 is arranged on the mounting ring 210 and is in sliding clamping connection with the outer wall of the lifting sleeve 20, and the stability of the lifting sleeve 20 during movement is improved by arranging the guide rod 2100, so that the running stability of the whole dewatering device is improved;
the extrusion dehydration assembly 3 comprises a dehydration barrel 30, an extrusion motor 31, an extrusion plate 32 and a driving motor 34, wherein the dehydration barrel 30 is sleeved inside the lifting sleeve 20, the upper end of the dehydration barrel 30 is opened, the lower end of the dehydration barrel is clamped with a movable plate 33, a plurality of water outlet holes 300 are formed in the side wall in a penetrating manner, two second connecting sleeves 301 are rotatably clamped on the side wall of the dehydration barrel 30, the two second connecting sleeves 301 are fixedly connected with the inner wall of the lifting sleeve 20 respectively, the extrusion plate 32 is slidably clamped at the opening of the upper end of the dehydration barrel 30, a vibration plate 320 is slidably clamped on the extrusion plate 32, a curved vibration sleeve 321 is arranged on the upper end face of the vibration plate 320, a mounting plate 311 is sleeved on the extrusion screw 310, extrusion rollers 312 are rotatably clamped at the lower end of the mounting plate 311, and the extrusion rollers 312 are abutted with the upper end face of the curved vibration sleeve 321; a sliding rod 3200 is arranged at the joint of the vibration plate 320 and the extrusion plate 32, a reset spring 3201 is sleeved on the sliding rod 3200, the upper end of the reset spring 3201 is in butt joint with the vibration plate 320, the lower end of the reset spring is in butt joint with the extrusion plate 32, and in the rotation process of the extrusion screw 310, the mounting plate 311 and the extrusion roller 312 are driven to rotate, so that the vibration plate 320 reciprocates up and down under the action of the extrusion roller 312, vibration extrusion dehydration of electroplating sludge is realized, and the dehydration efficiency of the electroplating sludge is improved; the extrusion motor 31 is arranged at the top of the outer shell 1, an extrusion screw 310 is arranged on an output shaft of the extrusion motor 31, the extrusion screw 310 penetrates through the extrusion plate 32 and is rotationally clamped with the inner bottom of the dehydration barrel 30, and the extrusion screw 310 is in threaded connection with the extrusion plate 32; the movable plate 33 is connected with the top of the water collection tank 10 through a shaft rod 330, a connecting gear 331 is sleeved on the shaft rod 330, a driving motor 34 is arranged on the top of the water collection tank 10, and a driving gear 340 meshed with the connecting gear 331 is arranged on an output shaft of the driving motor 34; the upper end of the water collection tank 10 is provided with the protective sleeve 12, the upper end of the protective sleeve 12 is rotationally clamped with the lower end surface of the movable plate 33, the driving motor 34 is positioned in the protective sleeve 12, and the protective sleeve 12 is arranged, so that the influence of sludge on the meshing effect of the connecting gear 331 and the driving gear 340 can be avoided;
The controller is respectively and electrically connected with the lifting motor 21, the extrusion motor 31 and the driving motor 34; the controller, the lift motor 21, the pressing motor 31, and the driving motor 34 are all commercially available products.
Example 11
A method for selectively extracting and recovering chromium elements in electroplating sludge comprises the following steps:
s1, pretreatment of electroplating sludge:
s1-1, introducing electroplating sludge into dehydration equipment, carrying out pressure maintaining dehydration treatment under the pressure of 2.5MPa for 55min, and drying until the water content reaches 13%, thereby obtaining dried sludge;
s1-2, placing the dried sludge obtained in the step S1-1 into a roasting furnace, roasting at 780 ℃ for 45min in an air atmosphere, naturally cooling, crushing, and sieving with a 50-mesh sieve to obtain sludge particles to be leached; placing sludge particles to be leached into a desiccator, and drying at 1050 ℃ for 45min; the sludge particles to be leached are subjected to drying treatment, so that organic matters and combustible impurities in the sludge particles to be leached can be effectively removed, the separation difficulty of chromium elements in electroplating sludge is reduced, and the extraction efficiency of the chromium elements is improved;
s2, acid leaching:
s2-1, preparing a sulfuric acid solution with the mass concentration of 11%, and then mixing the sulfuric acid solution with the sludge particles to be leached after the drying treatment obtained in the step S1-2 according to the volume ratio of 8:1 to obtain a mixture A; adding 11% by volume of a hydrogen peroxide solution with a volume concentration of 9% into the mixture A, and reacting for 60min at 185 ℃; the hydrogen peroxide solution is added into the mixture A, so that the conversion efficiency of hexavalent chromium in the mixture A can be improved, new metal ions can not be introduced, and the extraction efficiency of chromium elements in electroplating sludge is improved;
S2-2, heating the mixture A processed in the step S2-1 to 90 ℃, and then carrying out ultrasonic treatment at a frequency of 35kHz and a power of 880W for 60min to obtain a mixture B; finally, filtering the mixture B to obtain filtrate;
s2-3, standing the filtrate obtained in the step S2-2 for 85min, and then extracting supernatant to obtain leaching liquid; introducing the leaching solution into a high-pressure reaction kettle, controlling the temperature of the high-pressure reaction kettle to be 350 ℃, controlling the pressure to be 6MPa, continuously reacting for 25min, and discharging the high-pressure reaction kettle to obtain hot-water leaching solution; the leaching solution is subjected to hydrothermal treatment, so that viscous organic matters in the leaching solution can be decomposed, and meanwhile, the colloid structure in the leaching solution can be destroyed, and the enrichment efficiency of chromium element is improved;
s3, enriching chromium:
s3-1, adding an ethanol solution with the concentration of 13% into the hot water leaching solution obtained in the step S2-3, stirring and mixing uniformly, and then introducing into a gasification box for gasification treatment at the temperature of 480 ℃ to obtain gas-phase chromium element;
s3-2, introducing the gas-phase chromium element obtained in the step S3-1 into a ferrous sulfate heptahydrate solution with the mass concentration of 23% for reaction for 55min to form trivalent chromium precipitate, and separating the trivalent chromium precipitate; firstly, carrying out adsorption treatment on a ferrous sulfate heptahydrate solution by utilizing ion exchange resin, then desorbing the ion exchange resin by utilizing a sodium carbonate aqueous solution with the mass concentration of 18%, and separating sediment in desorption liquid; the ion exchange resin adsorption treatment is carried out on the ferrous sulfate heptahydrate solution, so that suspended chromium element in the ferrous sulfate heptahydrate solution can be effectively extracted; finally, the trivalent chromium precipitate is dried to constant weight at 120 ℃, and then is ball-milled into particles with the particle size of 1.5-1.8 mm; the trivalent chromium precipitate is dried and ball-milled, so that the collection and the utilization of chromium materials are facilitated.
Example 12
The embodiment describes a chromium element selective extraction and recovery device applicable to the electroplating sludge of the embodiment 11, which comprises a dehydration device for deep dehydration of the electroplating sludge, a roasting furnace for roasting the dry sludge, and a gasification box for gasification treatment of a mixed solution of leaching liquid and ethanol solution, wherein the dehydration device comprises an outer shell 1, a lifting assembly 2, an extrusion dehydration assembly 3 and a controller; the lower end of the outer shell 1 is provided with a water collecting tank 10, the water collecting tank 10 is communicated with the inside of the outer shell 1, and the side wall of the water collecting tank 10 is provided with a drain pipe 11;
the lifting assembly 2 comprises a lifting sleeve 20 and lifting motors 21, wherein the lifting sleeve 20 is movably sleeved inside the outer shell 1, a first connecting sleeve 200 is rotatably clamped at the lower position outside the lifting sleeve 20, the first connecting sleeve 200 is fixedly connected with the inner wall of the outer shell 1, two lifting motors 21 are symmetrically arranged at two sides inside the outer shell 1 through mounting rings 210 and are positioned at the upper end of the first connecting sleeve 200, lifting lead screws 211 are arranged on output shafts of the lifting motors 21, and the two lifting lead screws 211 respectively penetrate through the mounting rings 210 and are respectively in threaded connection with the first connecting sleeve 200; the guide rod 2100 is arranged on the mounting ring 210 and is in sliding clamping connection with the outer wall of the lifting sleeve 20, and the stability of the lifting sleeve 20 during movement is improved by arranging the guide rod 2100, so that the running stability of the whole dewatering device is improved;
The extrusion dehydration assembly 3 comprises a dehydration barrel 30, an extrusion motor 31, an extrusion plate 32 and a driving motor 34, wherein the dehydration barrel 30 is sleeved inside the lifting sleeve 20, the upper end of the dehydration barrel 30 is opened, the lower end of the dehydration barrel is clamped with a movable plate 33, a plurality of water outlet holes 300 are formed in the side wall in a penetrating manner, two second connecting sleeves 301 are rotatably clamped on the side wall of the dehydration barrel 30, the two second connecting sleeves 301 are fixedly connected with the inner wall of the lifting sleeve 20 respectively, the extrusion plate 32 is slidably clamped at the opening of the upper end of the dehydration barrel 30, a vibration plate 320 is slidably clamped on the extrusion plate 32, a curved vibration sleeve 321 is arranged on the upper end face of the vibration plate 320, a mounting plate 311 is sleeved on the extrusion screw 310, extrusion rollers 312 are rotatably clamped at the lower end of the mounting plate 311, and the extrusion rollers 312 are abutted with the upper end face of the curved vibration sleeve 321; a sliding rod 3200 is arranged at the joint of the vibration plate 320 and the extrusion plate 32, a reset spring 3201 is sleeved on the sliding rod 3200, the upper end of the reset spring 3201 is in butt joint with the vibration plate 320, the lower end of the reset spring is in butt joint with the extrusion plate 32, and in the rotation process of the extrusion screw 310, the mounting plate 311 and the extrusion roller 312 are driven to rotate, so that the vibration plate 320 reciprocates up and down under the action of the extrusion roller 312, vibration extrusion dehydration of electroplating sludge is realized, and the dehydration efficiency of the electroplating sludge is improved; the extrusion motor 31 is arranged at the top of the outer shell 1, an extrusion screw 310 is arranged on an output shaft of the extrusion motor 31, the extrusion screw 310 penetrates through the extrusion plate 32 and is rotationally clamped with the inner bottom of the dehydration barrel 30, and the extrusion screw 310 is in threaded connection with the extrusion plate 32; the movable plate 33 is connected with the top of the water collection tank 10 through a shaft rod 330, a connecting gear 331 is sleeved on the shaft rod 330, a driving motor 34 is arranged on the top of the water collection tank 10, and a driving gear 340 meshed with the connecting gear 331 is arranged on an output shaft of the driving motor 34; the upper end of the water collection tank 10 is provided with the protective sleeve 12, the upper end of the protective sleeve 12 is rotationally clamped with the lower end surface of the movable plate 33, the driving motor 34 is positioned in the protective sleeve 12, and the protective sleeve 12 is arranged, so that the influence of sludge on the meshing effect of the connecting gear 331 and the driving gear 340 can be avoided;
The controller is respectively and electrically connected with the lifting motor 21, the extrusion motor 31 and the driving motor 34; the controller, the lift motor 21, the pressing motor 31, and the driving motor 34 are all commercially available products.
Test examples
The method of the invention of the embodiments 1, 3, 5, 7, 9 and 11 is used for extracting and recycling chromium elements in electroplating sludge discharged from a certain electroplating plant in the north of China, and the chromium elements in the electroplating sludge are measured after the treatment is finished, and the results are shown in the table 1:
TABLE 1 Effect of various examples on the extraction efficiency of chromium element from electroplating sludge
| Examples | Cr 2+ Precipitation rate/% | Cr 2+ Extraction yield/% |
| 1 | 78.9 | 75.4 |
| 3 | 83.5 | 81.3 |
| 5 | 89.7 | 86.9 |
| 7 | 92.6 | 91.5 |
| 9 | 95.4 | 94.9 |
| 11 | 98.2 | 97.8 |
As can be seen from the data in table 1, compared with example 1, in example 3, by drying the sludge particles to be leached, organic matters and combustible impurities in the sludge particles to be leached can be effectively removed, the separation difficulty of chromium element in the electroplating sludge is reduced, and the extraction efficiency of chromium element is improved; example 5 by subjecting a ferrous sulfate heptahydrate solution to ion exchange resin adsorption treatment, it is possible to efficiently extract suspended chromium element in the ferrous sulfate heptahydrate solution, as compared with example 1; drying and ball milling are carried out on trivalent chromium precipitate, which is beneficial to collecting and utilizing chromium materials; example 7 compared with example 1, by subjecting the leachate to hydrothermal treatment, the viscous organic matter in the leachate can be decomposed, and the colloid structure in the leachate can be destroyed, so that the enrichment efficiency of chromium element can be improved; example 9 compared with example 1, by adding hydrogen peroxide solution to mixture a, the conversion efficiency of hexavalent chromium in mixture a can be improved, new metal ions can not be introduced, and the extraction efficiency of chromium element in electroplating sludge can be improved; compared with the embodiment 1, 3, 5, 7 and 9, the embodiment 11 realizes the recycling utilization of the electroplating sludge and improves the economic efficiency by integrating and optimizing the favorable conditions so that the precipitation rate and the extraction rate of chromium element in the electroplating sludge reach the optimal state.
Claims (9)
1. The method for selectively extracting and recovering chromium element in electroplating sludge is characterized by comprising the following steps of:
s1, pretreatment of electroplating sludge:
s1-1, introducing electroplating sludge into dehydration equipment, carrying out pressure maintaining dehydration treatment for 30-55 min under the pressure of 1.8-2.5 MPa, and drying until the water content is less than 20%, thereby obtaining dried sludge;
s1-2, placing the dried sludge obtained in the step S1-1 into a roasting furnace, roasting at 300-780 ℃ for 20-45 min in air atmosphere, naturally cooling, crushing, and sieving with a 20-50 mesh sieve to obtain sludge particles to be leached;
s2, acid leaching:
s2-1, preparing a sulfuric acid solution with the mass concentration of 5-11%, and then mixing the sulfuric acid solution with the sludge particles to be leached obtained in the step S1-2 according to the volume ratio of 5-8:1 to obtain a mixture A;
s2-2, heating the mixture A obtained in the step S2-1 to 30-90 ℃, and then carrying out ultrasonic treatment at a frequency of 22-35 kHz and a power of 630-880W for 20-60 min to obtain a mixture B; finally, filtering the mixture B to obtain filtrate;
s2-3, standing the filtrate obtained in the step S2-2 for 45-85 min, and extracting supernatant to obtain leaching liquid;
s3, enriching chromium:
s3-1, adding 5-13% ethanol solution into the leaching solution obtained in the step S2-3, stirring and mixing uniformly, and then introducing into a gasification box for gasification treatment at the temperature of 250-480 ℃ to obtain gas-phase chromium element;
S3-2, introducing the gas-phase chromium element obtained in the step S3-1 into a ferrous sulfate heptahydrate solution with the mass concentration of 15-23% to react for 30-55 min to form trivalent chromium precipitate, and separating the trivalent chromium precipitate.
2. The method for selectively extracting and recovering chromium elements from electroplating sludge according to claim 1, wherein after the step S1-2 is completed, the sludge particles to be leached are placed into a desiccator, and are desiccated for 25-45 min at the temperature of 880-1050 ℃.
3. The method for selectively extracting and recovering chromium from electroplating sludge according to claim 1, wherein after the step S3-2 is completed, the ferrous sulfate heptahydrate solution is firstly subjected to adsorption treatment by using ion exchange resin, then the ion exchange resin is desorbed by using sodium carbonate aqueous solution with the mass concentration of 12-18%, and the precipitate in the desorption solution is separated.
4. The method for selectively extracting and recovering chromium from electroplating sludge according to claim 1, wherein after the step S2-3 is completed, the leaching solution is introduced into a high-pressure reaction kettle, the temperature of the high-pressure reaction kettle is controlled to be 280-350 ℃, the pressure is controlled to be 3-6 MPa, the continuous reaction is carried out for 10-25 min, and the hot water leaching solution is obtained after the discharging of the high-pressure reaction kettle.
5. The method for selectively extracting and recovering chromium elements from electroplating sludge according to claim 1, wherein after the step S3-2 is completed, the trivalent chromium precipitate is dried to constant weight at the temperature of 90-120 ℃, and then is ball-milled into particles with the particle size of less than 2 mm.
6. The method for selectively extracting and recovering chromium from electroplating sludge according to claim 1, wherein 5-11% by volume of hydrogen peroxide solution with a concentration of 4-9% by volume is added to the mixture A after the completion of the step S2-1, and the mixture A is reacted at a temperature of 125-185 ℃ for 45-60 min.
7. A device for selectively extracting and recovering chromium elements from electroplating sludge used for the method of any one of claims 1-6, which is characterized by comprising a dehydration device for deep dehydration of the electroplating sludge, a roasting furnace for roasting the dried sludge, and a gasification box for gasification treatment of a mixed solution of leaching solution and ethanol solution, wherein the dehydration device comprises an outer shell (1), a lifting assembly (2), an extrusion dehydration assembly (3) and a controller; the water collecting tank (10) is arranged at the lower end of the outer shell (1), the water collecting tank (10) is communicated with the inside of the outer shell (1), and a drain pipe (11) is arranged on the side wall of the water collecting tank (10);
The lifting assembly (2) comprises a lifting sleeve (20) and lifting motors (21), the lifting sleeve (20) is movably sleeved inside the outer shell (1), a first connecting sleeve (200) is rotatably clamped at the lower position outside the lifting sleeve (20), the first connecting sleeve (200) is fixedly connected with the inner wall of the outer shell (1), the lifting motors (21) are two, the two lifting motors (21) are symmetrically arranged on two sides inside the outer shell (1) through mounting rings (210) and are positioned at the upper end of the first connecting sleeve (200), lifting lead screws (211) are arranged on output shafts of the lifting motors (21), and the two lifting lead screws (211) respectively penetrate through the mounting rings (210) and are respectively in threaded connection with the first connecting sleeve (200);
the extrusion dehydration assembly (3) comprises a dehydration barrel (30), an extrusion motor (31), an extrusion plate (32) and a driving motor (34), wherein the dehydration barrel (30) is sleeved inside a lifting sleeve (20), the upper end of the dehydration barrel (30) is provided with an opening, the lower end of the dehydration barrel is clamped with a movable plate (33), a plurality of water outlet holes (300) are formed in the side wall in a penetrating mode, two second connecting sleeves (301) are rotatably clamped on the side wall of the dehydration barrel (30), the two second connecting sleeves (301) are fixedly connected with the inner wall of the lifting sleeve (20) respectively, the extrusion plate (32) is slidably clamped at the opening of the upper end of the dehydration barrel (30), the extrusion motor (31) is arranged at the top of an outer shell (1), an extrusion screw (310) is arranged on an output shaft of the extrusion motor (31), the extrusion screw (310) is rotatably clamped with the bottom in the dehydration barrel (30) after penetrating through the extrusion plate (32), and the extrusion screw (310) is in threaded connection with the extrusion plate (32); the movable plate (33) is connected with the top of the water collection tank (10) through a shaft rod (330), a connecting gear (331) is sleeved on the shaft rod (330), the driving motor (34) is arranged at the top of the water collection tank (10), and a driving gear (340) meshed with the connecting gear (331) is arranged on an output shaft of the driving motor (34);
The controller is electrically connected with the lifting motor (21), the extrusion motor (31) and the driving motor (34) respectively.
8. The device for selectively extracting and recycling chromium elements from electroplating sludge according to claim 7, wherein the extruding plate (32) is slidably clamped with a vibrating plate (320), the upper end surface of the vibrating plate (320) is provided with a curved surface vibrating sleeve (321), the extruding screw (310) is sleeved with a mounting plate (311), the lower end of the mounting plate (311) is rotatably clamped with an extruding roller (312), and the extruding roller (312) is abutted against the upper end surface of the curved surface vibrating sleeve (321); the vibrating plate (320) is provided with a sliding rod (3200) at the joint of the vibrating plate (32), a return spring (3201) is sleeved on the sliding rod (3200), the upper end of the return spring (3201) is abutted to the vibrating plate (320), and the lower end of the return spring is abutted to the vibrating plate (32).
9. The device for selectively extracting and recovering chromium from electroplating sludge according to claim 7, wherein the mounting ring (210) is provided with a guide rod (2100), and the guide rod (2100) is slidably clamped with the outer wall of the lifting sleeve (20).
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