CN112142067B - Process for extracting ammonium chloride from waste etching liquid and evaporation concentration system thereof - Google Patents

Process for extracting ammonium chloride from waste etching liquid and evaporation concentration system thereof Download PDF

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CN112142067B
CN112142067B CN202010832937.0A CN202010832937A CN112142067B CN 112142067 B CN112142067 B CN 112142067B CN 202010832937 A CN202010832937 A CN 202010832937A CN 112142067 B CN112142067 B CN 112142067B
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ammonium chloride
extracting
pipeline
cylinder
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CN112142067A (en
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麻洪明
林小胡
何朋朋
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Wenzhou Kerui Environment Resource Utilization Co ltd
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Wenzhou Kerui Environment Resource Utilization Co ltd
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    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01C—AMMONIA; CYANOGEN; COMPOUNDS THEREOF
    • C01C1/00—Ammonia; Compounds thereof
    • C01C1/16—Halides of ammonium
    • C01C1/164—Ammonium chloride
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F9/00—Multistage treatment of water, waste water or sewage
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/001—Processes for the treatment of water whereby the filtration technique is of importance
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/02—Treatment of water, waste water, or sewage by heating
    • C02F1/04—Treatment of water, waste water, or sewage by heating by distillation or evaporation
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/02—Treatment of water, waste water, or sewage by heating
    • C02F1/04—Treatment of water, waste water, or sewage by heating by distillation or evaporation
    • C02F1/046—Treatment of water, waste water, or sewage by heating by distillation or evaporation under vacuum produced by a barometric column
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/26—Treatment of water, waste water, or sewage by extraction
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/28—Treatment of water, waste water, or sewage by sorption
    • C02F1/285—Treatment of water, waste water, or sewage by sorption using synthetic organic sorbents
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/52—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/66—Treatment of water, waste water, or sewage by neutralisation; pH adjustment
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/52—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities
    • C02F2001/5218—Crystallization
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2101/00—Nature of the contaminant
    • C02F2101/10—Inorganic compounds
    • C02F2101/16—Nitrogen compounds, e.g. ammonia
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2101/00—Nature of the contaminant
    • C02F2101/10—Inorganic compounds
    • C02F2101/20—Heavy metals or heavy metal compounds
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2103/00—Nature of the water, waste water, sewage or sludge to be treated
    • C02F2103/34—Nature of the water, waste water, sewage or sludge to be treated from industrial activities not provided for in groups C02F2103/12 - C02F2103/32
    • C02F2103/346—Nature of the water, waste water, sewage or sludge to be treated from industrial activities not provided for in groups C02F2103/12 - C02F2103/32 from semiconductor processing, e.g. waste water from polishing of wafers
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P10/00—Technologies related to metal processing
    • Y02P10/20—Recycling

Abstract

The invention discloses a process for extracting ammonium chloride from waste etching liquid and an evaporation concentration system thereof, which comprises the following process steps: s1, filtering alkaline waste etching solution to remove suspended impurities to obtain solution a, and regulating the pH value to 9-10; s2, extracting the solution a in a filler extraction tower to obtain an organic phase b and a raffinate c; s3, adding hydrochloric acid into the raffinate c for tempering to obtain a solution d; s4, in fixed bed adsorption equipment, heavy metal ions in the solution d are adsorbed by adopting L-glutamic acid chelate resin to obtain an ammonium chloride solution e and a desorption solution f; s5, evaporating and concentrating the ammonium chloride solution e to obtain ammonium chloride concentrated solution g; s6, cooling and crystallizing the ammonium chloride concentrated solution g. An evaporation concentration system comprises a liquid feeding device, a negative pressure evaporation device, a condensing device and a condensed water collecting device, wherein the devices are connected through pipelines. The present application can be used in waste treatment plants, which have the advantage of extracting the purity of ammonium chloride.

Description

Process for extracting ammonium chloride from waste etching liquid and evaporation concentration system thereof
Technical Field
The invention relates to the technical field of ammonium chloride recovery, in particular to a process for extracting ammonium chloride from waste etching liquid and an evaporation concentration system thereof.
Background
Printed Circuit Boards (PCBs) have been rapidly developed in recent years as an important component of electronic products, with increasing demands for PCBs as the electronic industry rapidly progresses. With the continuous development of the PCB industry, environmental protection of the industry is becoming more and more important, and one of the main pollution is a large amount of copper-containing etching waste liquid generated in the etching process. The waste liquid mainly comes from the PCB etching process, the etching liquid can corrode redundant copper foil on the circuit board, so that the concentration of copper ions in the etching liquid is continuously increased, and when the content of copper ions in the etching liquid reaches a certain concentration, the efficiency of etching copper by the etching liquid is gradually reduced until the etching liquid is invalid, thereby becoming etching waste liquid and being discharged. The etching waste liquid belongs to dangerous liquid waste, contains a large amount of copper, ammonia nitrogen, chlorine and other pollution components, and is directly discharged into the environment without strict treatment, so that not only is the waste and loss of resources caused, but also great harm is caused to human beings and natural environments.
The prior Chinese patent publication No. CN105002500B discloses a method for regenerating alkaline etching liquid by removing copper from waste alkaline etching liquid by evaporation, then adding acid for acidification, or directly adding acid for acidification, then cooling or freezing to separate copper out copper in the form of copper ammonium chloride double salt crystals, filtering to obtain copper ammonium chloride double salt crystals and a liquid after the copper ammonium chloride double salt crystals are crystallized, separating the obtained copper ammonium chloride double salt crystals to obtain copper, adding at least one of ammonia water, ammonia gas, hydrochloric acid and ammonium chloride into the obtained liquid after the crystallization to regenerate the copper, and returning the liquid to an etching process for continuous use, thereby fully and effectively utilizing the effective components in the waste alkaline etching liquid and avoiding secondary pollution. The method involves extracting copper from the solution with solvent to convert it into copper salt solution, and converting raffinate into NH 4 Cl solution or NH 4 Cl-HCl mixed solution, and the raffinate is directly used for preparing new etching solution; or ammonia is added into the raffinate to adjust the pH value to 1-5, and then the crystal ammonium chloride is concentrated, so that the obtained ammonium chloride is used for preparing etching new liquid or is sold as a product.
The method has the following defects: due to the fact that the raffinate contains no ammonium ions (NH) 4+ ) Chloride ion (CL) - ) There are also unextracted copper ions (Cu 2+ ) And other heavy metal impurities, although the ammonium chloride product with a certain content can be obtained through simple concentration treatment, the ammonium chloride product has lower purity and lower selling value.
Disclosure of Invention
A first object of the present application is to provide a process for extracting ammonium chloride from spent etching solution, which has the advantage of effectively improving the purity of ammonium chloride, aiming at the deficiencies of the prior art.
A second object of the present application is to provide an evaporation and concentration system which has the advantage of low energy consumption and high purity of the obtained ammonium chloride.
In order to achieve the first object, the present invention provides the following technical solutions: a process for extracting ammonium chloride from waste etching liquid, comprising the following steps:
s1, filtering alkaline waste etching solution to remove suspended impurities and adjusting the pH value to 9-10 to obtain solution a;
s2, extracting the solution a in a filler extraction tower to obtain an organic phase b and a raffinate c;
s3, adding hydrochloric acid into the raffinate c for tempering to obtain a solution d;
s4, in fixed bed adsorption equipment, heavy metal ions in the solution d are adsorbed by adopting L-glutamic acid chelate resin to obtain an ammonium chloride solution e and a desorption solution f;
s5, evaporating and concentrating the ammonium chloride solution e through an evaporating and concentrating system to obtain ammonium chloride concentrated solution g;
s6, cooling and crystallizing the ammonium chloride concentrated solution g to obtain solid ammonium chloride.
By adopting the technical scheme, after the waste etching solution is filtered and the suspended matters or solid particle impurities possibly existing are removed and the pH value is regulated, the obtained solution a is extracted to obtain an organic phase b and a raffinate c, and the organic phase b and the raffinate c are respectively processed in the next working procedure. Most copper ions in the solution a are extracted into the organic phase b, but a small amount of copper ions and other small amounts of heavy metal ions still remain in the raffinate c, and resin adsorption is performed after acid addition tempering to remove the copper ions and other small amounts of heavy metal ions remaining in the raffinate c, so that an ammonium chloride solution e is obtained, a series of steps such as evaporation concentration, cooling crystallization and the like are performed on the ammonium chloride solution e, and finally, an ammonium chloride product with higher purity is obtained, and the selling value of the product is improved.
Further, the extraction agent and the diluent are introduced into the packed extraction tower in the step S2, and the volume concentration ratio of the extraction agent to the diluent is 4:1, the extraction temperature is 10-60 ℃.
By adopting the technical scheme, the diluent is added into the extractant, so that the specific gravity and viscosity of the extractant can be effectively reduced, and the two phases flow and are more smoothly separated; the extraction temperature is in the range, so that the extraction can be performed at normal temperature without heating, heating equipment is omitted, and the energy consumption is reduced.
Further, the residence time of the solution d in the fixed bed adsorption equipment is 5-7 min, and the pH value is 4-8.
Further, in step S5, the evaporating and concentrating time is 30-60 min.
In order to achieve the second object, the present invention provides the following technical solutions: the evaporation concentration system is applied to the evaporation concentration process link and comprises a liquid feeding device, a negative pressure evaporation device, a condensation device and a condensate water collecting device, wherein the liquid feeding device is connected with the negative pressure evaporation device through a pipeline, the condensation device comprises a condensation pipe, an inner cavity and an outer cavity are formed in the condensation pipe, the condensation pipe is obliquely downwards arranged, the higher end of the inner cavity is communicated with the negative pressure evaporation device, and the lower end of the inner cavity is connected with the condensate water collecting device through a pipeline; two ends of the outer cavity are respectively connected with a pipeline of the liquid conveying device; the condensed water collecting device is also connected with a vacuum pump.
By adopting the technical scheme, the liquid feeding device feeds the ammonium chloride solution e into the negative pressure evaporation device, and hot steam is introduced into the negative pressure evaporation device, so that the temperature in the negative pressure evaporation device is increased. And (3) starting a vacuum pump, performing vacuum compression on the whole system environment, gradually increasing the vacuum degree of the negative pressure evaporation device along with the operation of the vacuum pump, and gradually increasing the temperature of the negative pressure evaporation device and the temperature of the ammonium chloride solution e to the evaporation temperature of the negative pressure environment, wherein the ammonium chloride solution e is boiled and evaporated, so that hot steam is generated.
The steam transpires and rises, and enters the condensing device along with the extraction of the vacuum pump, condensed water after condensation naturally flows down to enter the condensed water collecting device to be collected. The ammonium chloride solution e to be evaporated and concentrated is used as a condensing medium, flows from the lower end of the outer cavity of the condensing device to the upper end of the outer cavity, condenses the steam generated by the ammonium chloride solution e which is evaporated and concentrated, then flows into the liquid feeding device or the negative pressure evaporating device, not only can the effect of condensing the formed steam be achieved, but also the ammonium chloride solution e to be evaporated and concentrated can be preheated, and the heat loss is reduced.
Further, the negative pressure evaporation device comprises a cylinder, and a liquid outlet is formed in the bottom of the cylinder; the lower end and the upper end of one side of the cylinder body are respectively provided with a hot steam inlet and a hot steam outlet, and the hot steam enters the cylinder body from the hot steam inlet and is discharged from the hot steam outlet.
By adopting the technical scheme, the introduced hot steam enters from the hot steam inlet and is discharged from the hot steam outlet after being circularly heated in the cylinder, so that the hot steam can be recycled, and the energy consumption is reduced. And (3) discharging the ammonium chloride concentrated solution g subjected to multiple evaporation and concentration from a liquid outlet, and entering a crystallization separation device to continue the next crystallization separation.
Further, a plurality of layers of hollow flow guide heating plates which are communicated in sequence are arranged on the inner side of the cylinder body along the vertical direction, the two adjacent flow guide heating plates are respectively connected to the opposite cylinder walls of the cylinder body, the flow guide heating plates are all arranged obliquely downwards, and a through hole which is communicated with the adjacent flow guide heating plates is formed in one side of the flow guide heating plate, which is far away from a connecting point with the cylinder walls; the cylinder is provided with a hot steam inlet pipeline and a hot steam outlet pipeline, the lowest layer of the flow guide heating plate is communicated with the steam inlet pipeline, and the uppermost layer of the flow guide heating plate is communicated with the steam outlet pipeline.
Through adopting above-mentioned technical scheme, ammonium chloride solution e gets into negative pressure evaporation plant from liquid feed arrangement in, flows from top to bottom along the direction that the water conservancy diversion hot plate leaned down at the water conservancy diversion heating plate face, and hot steam gets into from the steam inlet pipeline of the lower floor of water conservancy diversion hot plate, and opposite with the direction that ammonium chloride solution e flows, flows from bottom to top along the water conservancy diversion hot plate in the water conservancy diversion hot plate, finally discharges through hot steam outlet pipeline. In the whole flowing process, the ammonium chloride solution e and the hot steam are not contacted, so that a good evaporating effect can be achieved, gas and liquid are separated, the pollution rate of the hot steam is reduced, and the hot steam can be recycled infinitely. In addition, because the diversion heating plates are obliquely arranged and connected at the first position, the flowing area of the ammonium chloride solution e is enlarged, and the evaporation rate of the ammonium chloride solution e in the descending process is accelerated.
Further, connecting pipes are arranged at the head and tail connecting ends of the diversion heating plates, and two ends of each connecting pipe are respectively communicated with the diversion heating plates in a sealing mode.
Through adopting above-mentioned technical scheme, the setting of connecting pipe, on the one hand intercommunication two adjacent water conservancy diversion hot plates makes whole water conservancy diversion hot plate system become the airtight system of cavity of a intercommunication to when gas flow through in the barrel, both play the temperature in the heating barrel, do not contact with the liquid in the barrel again. On the other hand, the arrangement of the connecting pipe provides a space for liquid to flow into the adjacent lower-layer diversion heating plate connected with the upper-layer diversion heating plate from the upper-layer diversion heating plate, so that the liquid can smoothly flow layer by layer. In addition, the connecting pipe is connected with two adjacent diversion heating plates, so that the diversion heating plates are not in a suspended state, and the supporting strength between the two inclined diversion heating plates is increased.
Further, one side of the negative pressure evaporation device is also provided with a reflux device, one end of a pipeline of the reflux device is fixedly connected with the liquid outlet end, and the other end of the pipeline of the reflux device is fixedly connected with a pipeline of the liquid delivery device, which is close to the cylinder body.
Through adopting above-mentioned technical scheme, ammonium chloride solution e carries out evaporation concentration again through reflux unit after evaporating concentration reaches the leakage fluid dram in negative pressure evaporation plant again, finally discharges from the leakage fluid dram after evaporating concentration many times, gets into crystallization separator.
In summary, the invention has the following beneficial effects:
in the first step, the L-glutamic acid chelating resin is preferably adopted to adsorb copper and other heavy metals in the raffinate, and the L-glutamic acid chelating resin has strong adsorptivity to copper ions and nickel ions in wastewater, so that a better adsorption effect is obtained, and purer mother liquor is provided for evaporating and concentrating ammonium chloride solution e in the raffinate in a subsequent process.
According to the evaporation concentration system, the negative pressure-steam evaporation concentration method is adopted, and under the synergistic effect of the liquid feeding device, the negative pressure evaporation device, the condensing device, the condensed water collecting device and the like, the ammonium chloride solution e is evaporated and concentrated, so that the energy consumption is low, the ammonium chloride with higher purity can be obtained in a short time, and the recovery rate of the ammonium chloride is greatly improved.
Drawings
FIG. 1 is a flow chart of an evaporative concentration system provided by the invention;
fig. 2 is used to show the internal structure of the negative pressure evaporation device.
Reference numerals: 1. a liquid feeding device; 2. a negative pressure evaporation device; 21. a cylinder; 211. a liquid outlet; 212. a hot steam inlet duct; 213. a hot steam outlet pipe; 214. a diversion heating plate; 215. a through hole; 216. a connecting pipe; 217. a liquid discharge valve; 3. a condensing device; 31. a condensing tube; 311. an inner cavity; 312. an outer cavity; 4. a condensed water collecting device; 5. a crystallization separation device; 6. a vacuum pump; 7. a reflow device; 71. a reflux pump; 8. a solenoid valve.
Detailed Description
The present application is described in further detail below with reference to the drawings and examples.
Examples
Example 1
In order to obtain an ammonium chloride product with higher purity, the application provides a process for extracting ammonium chloride from waste etching liquid, which at least comprises the following steps:
s1, filtering alkaline waste etching solution to remove suspended impurities and adjusting the pH value to 9 to obtain solution a;
s2, extracting the solution a in a filler extraction tower, and introducing the solution a into the filler extraction tower in advance, wherein the volume concentration ratio is 4:1, setting the extraction temperature to be 10 ℃ to obtain an organic phase b and a raffinate c;
s3, adding hydrochloric acid into the raffinate c for tempering to obtain a solution d;
s4, in fixed bed adsorption equipment, regulating the pH value to be 4, and adopting L-glutamic acid chelate resin to adsorb heavy metal ions in the solution d for 5min to obtain ammonium chloride solution e and desorption solution f;
s5, evaporating and concentrating the ammonium chloride solution e to obtain an ammonium chloride concentrated solution g, wherein the evaporating and concentrating time is 30min;
s6, cooling and crystallizing the ammonium chloride concentrated solution g to obtain solid ammonium chloride.
Based on the step S5, the present application further provides an evaporation concentration system, which is used in the evaporation concentration process link. Referring to fig. 1, the evaporation and concentration system comprises a liquid feeding device 1, a negative pressure evaporation device 2, a condensation device 3 and a condensed water collecting device 4, wherein the liquid feeding device 1 is positioned at one side of the negative pressure evaporation device 2 and is connected with the negative pressure evaporation device 2 through a pipeline, and a circulating pump for conveying liquid to the negative pressure evaporation device 2 is arranged in the liquid feeding device 1. The condensing device 3 comprises a condensing tube 31, an inner cavity 311 and an outer cavity 312 are formed in the condensing tube 31, the condensing tube 31 is positioned above the negative pressure evaporation device 2 and is obliquely downwards arranged, the higher end of the inner cavity 311 of the condensing tube 31 is connected with the negative pressure evaporation device 2 through a pipeline, and the lower end of the inner cavity 311 is connected with the condensed water collecting device 4 through a pipeline; two ends of the outer cavity 312 of the condensing device 3 are respectively connected with the pipeline of the liquid feeding device 1; the condensing medium enters the outer cavity 312 of the condensing tube 31 from one end of the pipeline of the liquid feeding device 1, flows from the lower end of the outer cavity 312 to the upper end of the outer cavity 312, flows out from the upper end of the outer cavity 312 to the other end of the pipeline of the liquid feeding device 1, and enters the negative pressure evaporation device 2 together with the liquid to be evaporated and concentrated or flows back into the liquid feeding device 1. The condensed water collecting device 4 is connected with a vacuum pump 6, and the inside of the negative pressure evaporation device 2 communicated with the condensing device 3 is vacuumized through the condensing device 3 communicated with the condensed water collecting device 4. Solenoid valves 8 are arranged on the pipelines, and the closing of the connecting pipelines 216 can be controlled according to the requirement.
The condensing medium of the condensing device 3 is ammonium chloride solution e to be evaporated and concentrated, the ammonium chloride solution e enters from the inclined lower end of the condensing device 3 through a circulating pump, passes through the outer layer of the condensing device 3 and then comes out from the inclined upper end of the condensing device 3, enters the negative pressure evaporating device 2 for negative pressure evaporation and concentration, and the ammonium chloride solution e to be evaporated and concentrated is preheated while condensing steam, so that heat loss is reduced.
The negative pressure evaporation device 2 comprises a cylinder 21, a hot steam inlet and a hot steam outlet are respectively formed in the lower end and the upper end of one side of the cylinder 21, a hot steam inlet pipeline 212 and a hot steam outlet pipeline 213 are respectively connected to the hot steam inlet and the hot steam outlet, hot steam enters the cylinder 21 from the hot steam inlet pipeline 212, circulates in the cylinder 21 for one week, and is discharged from the hot steam outlet pipeline 213.
The bottom of the cylinder 21 is provided with a liquid outlet 211, the end of the liquid outlet 211 is connected with the crystallization separation device 5, the liquid outlet 211 is connected with the crystallization separation device 5 through a pipeline, and a liquid outlet valve 217 is arranged on the pipeline close to the crystallization separation device 5.
One side of the negative pressure evaporation device 2 is also provided with a reflux device 7, one end of the reflux device 7 is fixedly connected with a liquid outlet end 211 of the cylinder 21, and the other end is fixedly connected with a liquid feeding pipeline of the liquid feeding device 1, which is close to the cylinder 21. The reflux device 7 is provided with a reflux pump 71, and the ammonium chloride concentrated solution g after the pre-effect evaporation concentration returns to the negative pressure evaporation device 2 again through the reflux device 7 for evaporation concentration again, is discharged from the liquid outlet 211 after multiple evaporation concentration, and enters the crystallization separation device 5.
And cooling the ammonium chloride concentrate g in the crystallization separation device 5 to generate crystal grains, discharging the generated crystal grains from the bottom of the crystallization separation device 5, and performing solid-liquid separation in a centrifugal machine to finally obtain a solid ammonium chloride product with higher purity.
Referring to fig. 2, a plurality of hollow guiding heating plates 214 which are sequentially communicated are arranged on the inner side of a cylinder 21 on the inner side of the negative pressure evaporation device 2 along the vertical direction, two adjacent guiding heating plates 214 are respectively connected to opposite cylinder walls of the cylinder 21, the guiding heating plates 214 are all obliquely arranged downwards, a through hole 215 which is communicated with the adjacent guiding heating plates 214 is formed in one side of the guiding heating plate 214 away from a connecting point with the cylinder wall, and a space is provided for liquid to flow into the adjacent guiding heating plate 214 on the lower layer connected with the upper guiding heating plate 214 from the upper guiding heating plate 214, so that the liquid can smoothly flow from the upper layer to the lower layer. The lowermost layer of the deflector heating plate 214 is in communication with the steam inlet pipe, and the uppermost layer of the deflector heating plate 214 is in communication with the steam outlet pipe. The connecting pipe 216 is arranged at the head and tail connecting ends of the diversion heating plates 214, two ends of the connecting pipe 216 are respectively communicated with the diversion heating plates 214 arranged up and down in a sealing way, and the connecting pipe has a supporting effect on the connection of two adjacent diversion heating plates 214.
The implementation principle is as follows:
the liquid feeding device feeds the ammonium chloride solution e into the negative pressure evaporation device, and hot steam is introduced into the negative pressure evaporation device to raise the temperature in the negative pressure evaporation device. And (3) starting a vacuum pump, performing vacuum compression on the whole system environment, gradually increasing the vacuum degree of the negative pressure evaporation device along with the operation of the vacuum pump, and gradually increasing the temperature of the negative pressure evaporation device and the temperature of the ammonium chloride solution e to the evaporation temperature of the negative pressure environment, wherein the ammonium chloride solution e is boiled and evaporated, so that hot steam is generated. The steam transpires and rises, and enters the condensing device along with the extraction of the vacuum pump, condensed water after condensation naturally flows down to enter the condensed water collecting device to be collected. The introduced hot steam enters from the hot steam inlet and is discharged from the hot steam outlet after being circularly heated in the cylinder, so that the hot steam can be recycled and the energy consumption is reduced. The ammonium chloride solution e to be evaporated and concentrated is used as a condensing medium, flows from the lower end of the outer cavity of the condensing device to the upper end of the outer cavity, condenses the steam generated by the ammonium chloride solution e which is evaporated and concentrated, then flows into the liquid feeding device or the negative pressure evaporating device, not only can the effect of condensing the formed steam be achieved, but also the ammonium chloride solution e to be evaporated and concentrated can be preheated, and the heat loss is reduced.
Example 2
S1, filtering alkaline waste etching solution to remove suspended impurities and adjusting the pH value to 9.5 to obtain solution a;
s2, extracting the solution a in a filler extraction tower, and introducing the solution a into the filler extraction tower in advance, wherein the volume concentration ratio is 4:2, setting the extraction temperature to be 30 ℃ to obtain an organic phase b and a raffinate c;
s3, adding hydrochloric acid into the raffinate c for tempering to obtain a solution d;
s4, in fixed bed adsorption equipment, regulating the pH value to be 6, and adopting L-glutamic acid chelate resin to adsorb heavy metal ions in the solution d for 6min to obtain an ammonium chloride solution e and a desorption solution f;
s5, evaporating and concentrating the ammonium chloride solution e to obtain an ammonium chloride concentrated solution g, wherein the evaporating and concentrating time is 45min;
s6, cooling and crystallizing the ammonium chloride concentrated solution g to obtain solid ammonium chloride.
The evaporation and concentration system is unchanged.
Example 3
S1, filtering alkaline waste etching solution to remove suspended impurities and adjusting the pH value to 10 to obtain solution a;
s2, extracting the solution a in a filler extraction tower, only introducing an extracting agent with equal concentration in the filler extraction tower in advance, setting the extraction temperature to be 60 ℃ to obtain an organic phase b and a raffinate c;
s3, adding hydrochloric acid into the raffinate c for tempering to obtain a solution d;
s4, in fixed bed adsorption equipment, regulating the pH value to 8, and adopting L-glutamic acid chelate resin to adsorb heavy metal ions in the solution d for 7min to obtain ammonium chloride solution e and desorption solution f;
s5, evaporating and concentrating the ammonium chloride solution e to obtain an ammonium chloride concentrated solution g, wherein the evaporating and concentrating time is 60min;
s6, cooling and crystallizing the ammonium chloride concentrated solution g to obtain solid ammonium chloride.
The evaporation and concentration system is unchanged.
Example 4
S1, filtering alkaline waste etching solution to remove suspended impurities and adjusting the pH value to 9.5 to obtain solution a;
s2, extracting the solution a in a filler extraction tower, and introducing the solution a into the filler extraction tower in advance, wherein the volume concentration ratio is 4:1, setting the extraction temperature to be 30 ℃ to obtain an organic phase b and a raffinate c;
s3, adding hydrochloric acid into the raffinate c for tempering to obtain a solution d;
s4, in fixed bed adsorption equipment, regulating the pH value to be 4, and adopting L-glutamic acid chelate resin to adsorb heavy metal ions in the solution d for 6min to obtain ammonium chloride solution e and desorption solution f;
s5, evaporating and concentrating the ammonium chloride solution e to obtain an ammonium chloride concentrated solution g, wherein the evaporating and concentrating time is 45min;
s6, cooling and crystallizing the ammonium chloride concentrated solution g to obtain solid ammonium chloride.
The evaporation and concentration system is unchanged.
Example 5
S1, filtering alkaline waste etching solution to remove suspended impurities and adjusting the pH value to 10 to obtain solution a;
s2, extracting the solution a in a filler extraction tower, and introducing the solution a into the filler extraction tower in advance, wherein the volume concentration ratio is 4:1, setting the extraction temperature to be 50 ℃ to obtain an organic phase b and a raffinate c;
s3, adding hydrochloric acid into the raffinate c for tempering to obtain a solution d;
s4, in fixed bed adsorption equipment, regulating the pH value to 8, and adopting L-glutamic acid chelate resin to adsorb heavy metal ions in the solution d for 5min to obtain an ammonium chloride solution e and a desorption solution f;
s5, evaporating and concentrating the ammonium chloride solution e to obtain an ammonium chloride concentrated solution g, wherein the evaporating and concentrating time is 45min;
s6, cooling and crystallizing the ammonium chloride concentrated solution g to obtain solid ammonium chloride.
The evaporation and concentration system is unchanged.
Example 6
S1, filtering alkaline waste etching solution to remove suspended impurities and adjusting the pH value to 9.5 to obtain solution a;
s2, extracting the solution a in a filler extraction tower, and introducing the solution a into the filler extraction tower in advance, wherein the volume concentration ratio is 4:1, setting the extraction temperature to be 30 ℃ to obtain an organic phase b and a raffinate c;
s3, adding hydrochloric acid into the raffinate c for tempering to obtain a solution d;
s4, in fixed bed adsorption equipment, regulating the pH value to be 4, and adopting L-glutamic acid chelate resin to adsorb heavy metal ions in the solution d for 3min to obtain ammonium chloride solution e and desorption solution f;
s5, evaporating and concentrating the ammonium chloride solution e to obtain an ammonium chloride concentrated solution g, wherein the evaporating and concentrating time is 25min;
s6, cooling and crystallizing the ammonium chloride concentrated solution g to obtain solid ammonium chloride.
The evaporation and concentration system is unchanged.
Example 7
S1, filtering alkaline waste etching solution to remove suspended impurities and adjusting the pH value to 9.5 to obtain solution a;
s2, extracting the solution a in a filler extraction tower, and introducing the solution a into the filler extraction tower in advance, wherein the volume concentration ratio is 4:1, setting the extraction temperature to be 30 ℃ to obtain an organic phase b and a raffinate c;
s3, adding hydrochloric acid into the raffinate c for tempering to obtain a solution d;
s4, in fixed bed adsorption equipment, regulating the pH value to be 4, and adopting L-glutamic acid chelate resin to adsorb heavy metal ions in the solution d for 10min to obtain ammonium chloride solution e and desorption solution f;
s5, evaporating and concentrating the ammonium chloride solution e to obtain an ammonium chloride concentrated solution g, wherein the evaporating and concentrating time is 70min;
s6, cooling and crystallizing the ammonium chloride concentrated solution g to obtain solid ammonium chloride.
The evaporation and concentration system is unchanged.
Example 8
S1, filtering alkaline waste etching solution to remove suspended impurities and adjusting the pH value to 12 to obtain solution a;
s2, extracting the solution a in a filler extraction tower, and introducing the solution a into the filler extraction tower in advance, wherein the volume concentration ratio is 4:1, setting the extraction temperature to be 30 ℃ to obtain an organic phase b and a raffinate c;
s3, adding hydrochloric acid into the raffinate c for tempering to obtain a solution d;
s4, in fixed bed adsorption equipment, regulating the pH value to be 10, and adopting L-glutamic acid chelate resin to adsorb heavy metal ions in the solution d for 6min to obtain ammonium chloride solution e and desorption solution f;
s5, evaporating and concentrating the ammonium chloride solution e to obtain an ammonium chloride concentrated solution g, wherein the evaporating and concentrating time is 45min;
s6, cooling and crystallizing the ammonium chloride concentrated solution g to obtain solid ammonium chloride.
The evaporation and concentration system is unchanged.
Example 9
S1, filtering alkaline waste etching solution to remove suspended impurities and adjusting the pH value to 7 to obtain solution a;
s2, extracting the solution a in a filler extraction tower, and introducing the solution a into the filler extraction tower in advance, wherein the volume concentration ratio is 4:1, setting the extraction temperature to be 30 ℃ to obtain an organic phase b and a raffinate c;
s3, adding hydrochloric acid into the raffinate c for tempering to obtain a solution d;
s4, in fixed bed adsorption equipment, regulating the pH value to be 3, and adopting L-glutamic acid chelate resin to adsorb heavy metal ions in the solution d for 6min to obtain an ammonium chloride solution e and a desorption solution f;
s5, evaporating and concentrating the ammonium chloride solution e to obtain an ammonium chloride concentrated solution g, wherein the evaporating and concentrating time is 45min;
s6, cooling and crystallizing the ammonium chloride concentrated solution g to obtain solid ammonium chloride.
The evaporation and concentration system is unchanged.
Performance test
Test method
In practice, a comprehensive test record was performed according to the examples, and the purity of ammonium chloride obtained in each example was calculated.
Purity of epiammonium chloride
Figure BDA0002638644810000101
From the above, it can be seen that, in the set pH and temperature range, copper ions in the waste etching solution after impurity removal are extracted by using the extraction system with corresponding proportion, then, in the set pH range, copper ions and other heavy metal ions remained in the raffinate are adsorbed by using the L-glutamic acid chelating resin, finally, the raffinate is evaporated and concentrated by using the evaporation and concentration system, and cooled and crystallized, so that the purity of the obtained ammonium chloride is higher, and from the above table, the purity of the ammonium chloride obtained in example 4 is highest. Therefore, the extraction condition has the pH value of 9.5, the temperature of 30 ℃, and the extraction effect is optimal when the ratio of the extractant to the diluent is 4:1. Then, at the pH value of 4 and normal temperature, the L-glutamic acid chelating resin is used for absorbing heavy metal ions, and the absorption time is 6min, so that the absorption effect is better. And finally evaporating and concentrating for 30min in an evaporating and concentrating system, so that the effect is optimal.
As can be seen from examples 4, 8 and 9, the alkaline waste etching solution is filtered to remove suspended impurities to obtain solution a, the pH value is not adjusted before extraction or the raffinate c is quenched and tempered without adding hydrochloric acid after extraction, the purity of ammonium chloride is obviously reduced, and the reduction range is larger, so that the pH value has a great influence on the purity of extracted ammonium chloride.
It can be seen from examples 4, 6 and 7 that too short a residence time of the solution d obtained after the acid conditioning raffinate c in the fixed bed adsorption equipment results in incomplete adsorption or too short an evaporation concentration time in the evaporation equipment at a negative pressure, which greatly reduces the purity of ammonium chloride, and thus it is important to control the time during the reaction.
As can be seen from examples 1, 2 and 3, the pure addition of the extractant without the diluent in the extraction system results in an ammonium chloride having a purity significantly lower than that obtained by the addition of both the extractant and the diluent; however, the addition of an excessive amount of diluent also affects the purity of the final ammonium chloride.
The present embodiment is only for explanation of the present invention and is not to be construed as limiting the present invention, and modifications to the present embodiment, which may not creatively contribute to the present invention as required by those skilled in the art after reading the present specification, are all protected by patent laws within the scope of claims of the present invention.

Claims (7)

1. A process for extracting ammonium chloride from a spent etching solution, comprising at least the steps of:
s1, filtering alkaline waste etching solution to remove suspended impurities and adjusting the pH value to 9-10 to obtain solution a;
s2, extracting the solution a in a filler extraction tower to obtain an organic phase b and a raffinate c;
s3, adding hydrochloric acid into the raffinate c for tempering to obtain a solution d;
s4, in fixed bed adsorption equipment, heavy metal ions in the solution d are adsorbed by adopting L-glutamic acid chelate resin to obtain an ammonium chloride solution e and a desorption solution f;
s5, evaporating and concentrating the ammonium chloride solution e through an evaporating and concentrating system to obtain ammonium chloride concentrated solution g;
s6, cooling and crystallizing the ammonium chloride concentrated solution g to obtain solid ammonium chloride;
the extraction tower of the filling material in the step S2 is introduced with an extracting agent and a diluting agent, and the volume concentration ratio of the extracting agent to the diluting agent is 4:1, the extraction temperature is 10-60 ℃;
the residence time of the solution d in the fixed bed adsorption equipment is 5-7 min, and the pH value is 4-8.
2. The process for extracting ammonium chloride from waste etching solution according to claim 1, wherein in step S5, the evaporation concentration time is 30min to 60min.
3. The process for extracting ammonium chloride from waste etching liquid according to claim 1, wherein the evaporation concentration system comprises a liquid feeding device (1), a negative pressure evaporation device (2), a condensation device (3) and a condensed water collecting device (4), wherein the liquid feeding device (1) is connected with the negative pressure evaporation device (2) through a pipeline, the condensation device (3) comprises a condensation pipe (31), an inner cavity (311) and an outer cavity (312) are formed in the condensation pipe (31), the condensation device (3) is obliquely arranged downwards, the higher end of the inner cavity (311) is communicated with the negative pressure evaporation device (2), the lower end of the inner cavity (311) is connected with the condensed water collecting device (4) through a pipeline, and two ends of the outer cavity (312) are respectively connected with the pipeline of the liquid feeding device (1); the condensed water collecting device (4) is also connected with a vacuum pump (6).
4. A process for extracting ammonium chloride from waste etching liquid according to claim 3, wherein the negative pressure evaporation device (2) comprises a cylinder (21), and a liquid outlet (211) is formed in the bottom of the cylinder (21); the lower end and the upper end of one side of the cylinder (21) are respectively provided with a hot steam inlet and a hot steam outlet, and the hot steam enters the cylinder (21) from the hot steam inlet and is discharged from the hot steam outlet.
5. The process for extracting ammonium chloride from waste etching liquid according to claim 4, wherein a plurality of layers of hollow sequentially communicated flow guide heating plates (214) are arranged on the inner side of the cylinder (21) along the vertical direction, the two adjacent flow guide heating plates (214) are respectively connected to opposite cylinder walls of the cylinder (21), the flow guide heating plates (214) are all obliquely downwards arranged, and a through hole (215) communicated with the adjacent flow guide heating plates (214) is formed on one side, far away from a connecting point of the flow guide heating plates (214) with the cylinder walls;
the steam-assisted heating device is characterized in that a hot steam inlet pipeline (212) and a hot steam outlet pipeline (213) are arranged on the cylinder body (21), the lowest layer of the flow-guiding heating plate (214) is communicated with the steam inlet pipeline (212), and the uppermost layer of the flow-guiding heating plate (214) is communicated with the steam outlet pipeline (213).
6. The process for extracting ammonium chloride from waste etching liquid according to claim 5, wherein connecting pipes (216) are arranged at the head and tail connecting ends of the diversion heating plates (214), and two ends of each connecting pipe (216) are respectively communicated with the diversion heating plates (214) in a sealing way.
7. A process for extracting ammonium chloride from waste etching liquid according to claim 3, wherein a reflux device (7) is further arranged at one side of the negative pressure evaporation device (2), one end of a pipeline of the reflux device (7) is fixedly connected with a liquid outlet (211) end, and the other end of the pipeline of the reflux device is fixedly connected with a pipeline of the liquid feeding device (1) close to the cylinder (21).
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EP2252404A1 (en) * 2008-02-14 2010-11-24 Soane Energy, LLC Systems and methods for removing finely dispersed particulate matter from a fluid stream
CN104628069A (en) * 2015-01-13 2015-05-20 河南农业大学 Device for performing negative pressure evaporation and concentration on biogas fluid
CN103288172B (en) * 2013-05-20 2015-09-30 深圳市危险废物处理站有限公司 PCB etches the recoverying and utilizing method washing plate waste water that workshop section produces

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CN101391799A (en) * 2007-09-20 2009-03-25 深圳市东江环保股份有限公司 Method for recovery processing of ammonia nitrogen from printed circuit board waste liquid
EP2252404A1 (en) * 2008-02-14 2010-11-24 Soane Energy, LLC Systems and methods for removing finely dispersed particulate matter from a fluid stream
CN103288172B (en) * 2013-05-20 2015-09-30 深圳市危险废物处理站有限公司 PCB etches the recoverying and utilizing method washing plate waste water that workshop section produces
CN104628069A (en) * 2015-01-13 2015-05-20 河南农业大学 Device for performing negative pressure evaporation and concentration on biogas fluid

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