CN105603434A - Method for recycling PCB (printed circuit board) acidic etching solution under photocatalytic actions - Google Patents

Method for recycling PCB (printed circuit board) acidic etching solution under photocatalytic actions Download PDF

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CN105603434A
CN105603434A CN201610162230.7A CN201610162230A CN105603434A CN 105603434 A CN105603434 A CN 105603434A CN 201610162230 A CN201610162230 A CN 201610162230A CN 105603434 A CN105603434 A CN 105603434A
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etching
copper
liquid
circuit board
waste liquor
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CN105603434B (en
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黄洪
邢征
司徒粤
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South China University of Technology SCUT
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South China University of Technology SCUT
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    • CCHEMISTRY; METALLURGY
    • C23COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23FNON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
    • C23F1/00Etching metallic material by chemical means
    • C23F1/46Regeneration of etching compositions
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01JCHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J27/00Catalysts comprising the elements or compounds of halogens, sulfur, selenium, tellurium, phosphorus or nitrogen; Catalysts comprising carbon compounds
    • B01J27/24Nitrogen compounds
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01JCHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J35/00Catalysts, in general, characterised by their form or physical properties
    • B01J35/30Catalysts, in general, characterised by their form or physical properties characterised by their physical properties
    • B01J35/39Photocatalytic properties
    • CCHEMISTRY; METALLURGY
    • C07ORGANIC CHEMISTRY
    • C07CACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C51/00Preparation of carboxylic acids or their salts, halides or anhydrides
    • C07C51/41Preparation of salts of carboxylic acids
    • C07C51/412Preparation of salts of carboxylic acids by conversion of the acids, their salts, esters or anhydrides with the same carboxylic acid part
    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22BPRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B15/00Obtaining copper
    • C22B15/0063Hydrometallurgy
    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22BPRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B7/00Working 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
    • C22B7/006Wet processes

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  • Engineering & Computer Science (AREA)
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  • Chemical Kinetics & Catalysis (AREA)
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Abstract

The invention discloses a method for recycling a PCB (printed circuit board) acidic etching solution under photocatalytic actions. The method comprises the following steps: an etching waste solution overflowing from an etching cylinder on the production line flows into a waste solution collection tank; the etching waste solution flows into an oxidation reaction tank from the waste solution collection tank, and reacts by adding a photocatalyst under lighting conditions; the oxidated waste solution flows into a precipitation reaction kettle provided with a cation exchange membrane, and meanwhile, a precipitant is added to form a precipitate-containing mixed solution; the mixed solution is subjected to solid-liquid separation; part of the filter residue is refined and purified, and then is sold in the form of cupric oxalate, and the rest is decomposed into activated copper oxide for sale; the filtrate flows into a dewatering system after hydrochloric acid is supplemented, thereby removing excessive moisture; and finally, the filtrate flows into a storage tank to become the recycled solution for etching. The copper is reutilized in the technical process: the copper is extracted properly by balanced operation, and part of copper is recycled. Only a certain amount of clean water is discharged, and no waste solution is discharged, thereby implementing closed cycle production. The process is simple in equipment and convenient to control, has wide popularization prospects, and has obvious economic value and social and environmental benefits.

Description

The method of a kind of photocatalysis PCB acidic etching liquid recycling
Technical field
The present invention relates to circuit board etching waste liquor recycling field, be specifically related to the method for a kind of photocatalysis PCB acidic etching liquid recycling.
Background technology
Printed circuit board (PCB) industry is one of most important element in electronics industry, has very important status in electronics and information industry, in recent years along with the developing rapidly of electronic industry, to the increase day by day of PCB demand. Acid etching is the important procedure that printed circuit board (pcb) is manufactured, in production process, produce a large amount of high copper waste etching solutions, etching waste liquor belongs to dangerous liquid refuse, contain a large amount of pollutant components such as copper, chlorine, if be just directly discharged in environment without strict processing, not only cause waste and the loss of resource, and can cause very large harm to Human and nature environment. In addition, the copper ion in etching waste liquor and chlorion also have very high recovery value, and under the current circumstances that resource is day by day in short supply and environment situation is increasingly serious, how the strict also so large-tonnage waste liquid of appropriate processing is a very important problem.
Acidic etching waste liquid is the industrial wastewater that a kind of copper content is higher, acidity is larger producing in etching Copper Foil process. Acidic etching waste liquid serious environment pollution, affects the existence of microorganism in water, and spoiled soil crumb structure, affects crop growth. All there is open defect in the circulating and recovering technology of existing acidic etching liquid, be subject to the restriction of the aspects such as cost recovery, regenerated liquid quality, control difficulty, technique continuity, and the deficiency of medium-sized and small enterprises to equipment investment ability, most factories that adopt acid etching technique do not adopt reuse technology, process but waste liquid is given to environmental protection company.
Although according to pertinent regulations, relevant department requires industrial wastewater to focus on, but but unavoidably have following problem for PCB etching solution Wastewater Concentrated: first, sewage disposal operating cost is higher, because waste water comes from different production technologies, therefore waste water quality is very complicated, single treatment process can not solve all problems, therefore to realize qualified discharge for more unmanageable industrial park waste water, adopt physical-chemical-biological group technology, conventionally all can significantly increase operating cost and add the chemical methodes such as medicament; The second, it is high that sewage disposal device investment requires, and by national requirements, sewage treatment equipment investment is up to the more than 1,000 ten thousand qualified processing PCB waste water of manufacturer's, and unablely for medium-sized and small enterprises complete this investment; The 3rd, etching solution recovery utilization rate is low, China conventionally only reclaims copper higher value ratio in waste liquid for PCB etching solution wastewater treatment process present stage, and has ignored the processing reuse of the pollutant components such as chlorine wherein, therefore fails thoroughly to accomplish " as far as possible entirely reclaim, discharge less or not ". Chlorion is the accelerator in acid etching technique, and PCB enterprise needs extra a large amount of chloride ion-containing that adds in etch process, will cause a large amount of wastes of resource if can not reclaim. Because sewage treatment plant is difficult to the long-term stable water outlet qualified discharge that ensures, will certainly cause environment to cause certain destruction also to increase production and environmental protection cost simultaneously. Therefore, the complete circulating and recovering technology of exploitation acidic etching waste liquid has great economy and social environment value.
The main component of acidic etching waste liquid is H at present2CuCl4Or CuCl2, treatment technology mainly contains and sodium hydroxide solution neutralisation, chemical precipitation method, solvent extraction, ion-exchange, floatation, absorption method, electrolysis etc. But PCB liquid waste processing is difficult to accomplish reclaim completely copper and the thorough environmental issue that solves makes the best of both worlds. By each PCB manufacturer by oneself waste liquid often only focus on reclaiming copper, fail thoroughly to solve environmental issue, so national regulation focuses on PCB waste liquid. Owing to processing PCB waste liquid, reclaim the good in economic efficiency of copper, the numerous and confused application of numerous businessmans is set up environmental protection company and is processed PCB waste liquid. Some company sizes are little, be simply equipped, and the qualified discharge of failing to dispose waste liquid, to this, the government of electron trade developed regions puts into effect policy, strengthens management, as put into effect file in October, 2014 and improve the rate of recovery and the wastewater discharge standard of copper in Jiangsu Province, and regulation PCB waste liquid treatment station must have certain scale, equipment construction investment must ability standard be founded the factory more than 1,000 ten thousand yuan.
Although files specify PCB discharging of waste liquid after treatment standard is that copper content is less than 5ppm, because China's PCB wastewater discharge is large, the annual copper running off is still counted in ten thousand tons.
Summary of the invention
The object of the invention is to overcome the shortcoming of prior art, provide a kind of the very little equipment investment of needs just can realize and utilize the method for catalytic oxidation air to carry out closed cycle recycling system to acidic etching liquid, this system can realize avoids etching solution discharge of wastewater. And by the precipitation method, the copper ion in etching solution is recycled, avoid the problem of Wastewater Concentrated. Because content of copper ion after national regulation wastewater treatment is at 5ppm, although very little, still there is copper to run off. Because this project system is a system for sealing, after etching solution repeatedly circulates, can realize copper and be bordering on 100% recycling. Thereby avoid the loss by copper in the waste liquid obtaining after focusing on, realize economic environmental protection interests and maximize. And under PCB factory normal operating condition, only increase by two devices of catalytic oxidation and water counter-infiltration, and the former introduces airborne oxygen, and the latter draws the water producing through reaction, can realize normal PCB pickling operation, i.e. and closed cycle is produced. The realization of this technique, has not only thoroughly solved existing PCB waste water handling problem (zero-emission), and there is no the loss of copper. This technology small investment, society and remarkable in economical benefits. Increase by two devices that price is not high in each PCB factory, just can solve puzzlement PCB industry PCB liquid waste processing problem for many years.
Object of the present invention is achieved through the following technical solutions: by using photochemical catalyst/non-metal kind conductor compound as photochemical catalyst, in air being passed into system under illumination condition to univalent copper ion catalytic oxidation, add subsequently precipitating reagent copper to be precipitated from etching waste liquor to recovery, control precipitating reagent addition, retain acidity, after allotment, again as etching agent, recycle thereby realize. The cupric oxalate that precipitation is extracted can be purified and be sold into refining cupric oxalate, realizes maximization of economic benefit, further improves the added value of copper in waste liquid.
The method that circuit board etching waste liquor circulating and recovering and copper reclaim, concrete steps are as follows:
1) etching waste liquor flows out and enters into waste collection tank from the etching cylinder of etching production line, owing to not adding oxidant, contains a large amount of Cu in this etching waste liquor+
2) etching waste liquor flow into oxidation reaction pond from waste collection tank, the compressed system that enters of air, Cu+Ion is oxidized under the effect of porous photocatalytic agent and illumination;
3) oxidized waste liquid flows in sedimentation basin, adds precipitating reagent by the amount of the tolerance of solution simultaneously, under stirring action, precipitation reaction occurs, and forms and contains sedimentary mixed liquor;
4) mixed liquor enters in tripod pendulum type batch centrifugal and carries out Separation of Solid and Liquid, and solid filter residue is mainly the sediment of copper, and filter residue is drawn off and collects pendingly, and copper content in filtrate will be reduced to approximately 80 ~ 160g/L;
5) according to market demand value, purify refining a part of filter residue, sell with the form of cupric oxalate; Another part resolves into active oxidation copper to be sold.
6) after mixed liquor Separation of Solid and Liquid, liquid is mainly acidic etching liquid body, in dioxygen oxidation process, reacts and has generated water with the hydrogen ion in system, and than former etching solution, the amount of water has risen. And in course of reaction, hydrochloric acid inevitably can volatilize, cause acid equivalent to reduce, so, in the process that enters etching working solution, need to supplement hydrochloric acid and ensure that acid equivalent is constant. And then make the water yield increase. So, filtrate is flowed in reverse osmosis membrane de-watering apparatus, too much water is removed.
7) filtrate flow in holding vessel, become for etched reuse liquid, and reuse liquid pipeline is linked on the pipeline that etching cylinder added water originally, adding this reuse liquid in etching cylinder by proportion management and control, some additives still add and carry out etching production according to acid equivalent management and control.
Further, described in step 1) etching waste liquor from the etching cylinder of etching production line, to flow out the flow velocity that enters into waste collection tank be 2 ~ 6m3/h。
Further, step 2) flow velocity of described air is 10 ~ 20m3/ h, the intensity of illumination is 400 ~ 1000W.
Further, step 2) described porous photocatalytic agent is the composite of photochemical catalyst/non-metal kind conductor.
Further, described photochemical catalyst is titanium dioxide or carbonitride; Described non-metal kind conductor is conductor Graphene, graphene oxide, redox graphene or the silane that is insoluble to strong acid.
Further, step 2) the process spent time of described oxidation is 1 ~ 2h.
Further, described in step 3), the flow velocity of waste liquid is 2 ~ 6m3/h。
Further, the precipitating reagent described in step 3) is oxalic acid.
Further, the sedimentation basin described in step 3) is cation-exchange membrane sedimentation basin.
Further, the active oxidation copper described in step 5) gets by calcining highly purified cupric oxalate precipitation.
Compared with prior art, the present invention has the following advantages and technique effect:
1) the present invention replaces the chloride oxidant of tradition by the oxo of air in acid cleaning process, avoids chlorine effusion in production process.
2) the present invention can realize and in technical process, reuse copper, suitably extracts copper according to balancing run, recycles part copper.
3) the present invention only has a small amount of clean water to discharge in whole technical process, and without discharging of waste liquid, accomplishes closed cycle production.
4) flow sheet equipment of the present invention is simple, control is convenient, and promotion prospect is wide, has significant economic worth and social environment benefit.
Brief description of the drawings
Fig. 1 is process chart of the present invention.
Detailed description of the invention
Embodiment 1
Composite (the redox graphene RGO/C of photochemical catalyst/non-metal kind conductor3N4Compound) preparation method as follows:
(1) carbonitride (C3N4) preparation: by grinding after melamine calcining, obtain carbonitride (C3N4) pale yellow powder, calcining heat is 550 DEG C, calcination time is 4h.
(2) preparation of GO:
(a) getting 2.5g graphite powder and 1.25g sodium nitrate, to be dissolved in 60ml mass concentration be in 95% the concentrated sulfuric acid, ice bath, and the time is 30min.
(b) add 7.5g potassium permanganate, under normal temperature, stir, mixing time is 12h.
(c) add the deionized water of 75ml, under high temperature, stir, temperature is 90 DEG C, and mixing time is 24h.
(d) adding while stirring 25ml mass concentration is 30% hydrogenperoxide steam generator again, obtains mixture.
(e) mixture is centrifugal, product, with dry after dilute hydrochloric acid solution and deionized water washing, obtains GO. Baking temperature is 60 DEG C. Watery hydrochloric acid mass concentration is 5%.
(3)RGO/C3N4The preparation of compound
(a) the above-mentioned GO making is joined in the deionized water of 60ml to ultrasonic 1h.
(b) add again 0.5gC3N4Powder, continues, after ultrasonic 30min, mixed liquor is stirred to 12h at normal temperatures.
(c) in mixed liquor, add 10ml methyl alcohol, under stirring, with 500W Xenon light shining 3h, make redox graphene RGO/C3N4Compound.
Below in conjunction with drawings and Examples, the invention will be further described:
As shown in Figure 1, the technical scheme that in etching waste liquid of circuit board of the present invention, the recovery method of copper adopts comprises the steps:
One, in the etching cylinder of acidic etching liquid from production line with 6m3/ h flows out, and owing to not adding oxidant in this process, contains the univalent copper ion of 2g/L in etching solution. Acidic etching liquid to be regenerated flows in waste collection tank.
Two, acidic etching waste liquid flow in illumination oxidation reaction pond from waste collection tank, to adopt pressure be 5kg air compressor by air with 20m3The speed of/h is pressed in system from 1000 holes, and guarantee and acidic etching waste liquid have larger contact area. By redox graphene RGO/C3N4Compound joins in reaction tank by the consumption of 1mg/L, and adopts 1000W strong illumination 1h. In this process, univalent copper ion is become bivalent cupric ion by airborne dioxygen oxidation, the hydrogen ion water generation reaction in oxygen and system.
Three, the acidic etching liquid that completes regeneration due to etching copper enter solution, cause the amount of copper in etching solution to raise compared with initial concentration. Now, by oxidation after acidic etching liquid with 6m3/ h flows in cation-exchange membrane sedimentation basin, and the consumption by 3g/L in sedimentation basin adds oxalic acid, obtains mixed liquor; Because oxalic acid is solid at normal temperatures, and can release hydrogen ions soluble in water and oxalate denominationby, combine with copper ion oxalic copper precipitation of oxalate denominationby, because the amount of the copper precipitating in this process is very little than stoste, in cupric oxalate precipitation, the content of chlorion is also very little, can ignore. The hydrogen ion discharging in oxalic acid course of dissolution enters in system, replenishes the hydrogen ion consuming in oxidation step, keeps acidic etching liquid acid equivalent constant.
Four, mixed liquor enters and in tripod pendulum type batch centrifugal, carries out Separation of Solid and Liquid, and solid filter residue is mainly cupric oxalate precipitation, and filter residue is drawn off and collects pendingly, and copper content in filtrate will be reduced to 120g/L, i.e. the concentration of copper ion in original acidic etching liquid. The time of mix and blend precipitating reagent and acidic etching waste liquid is controlled at 15 minutes; The too short time causes precipitating insufficient, and crystallization is meticulous, and the long processing time is nonsensical.
Five, because the demand for cupric oxalate on market is also little, required by market, by soluble in water a part of filter residue, refilter the cupric oxalate obtaining after purification, now cupric oxalate content exceedes 99.9%, and sells with the form of this highly purified cupric oxalate; Another part resolves into active oxidation copper to be sold, and active oxidation copper gets by calcining highly purified cupric oxalate precipitation, and calcining heat is 400 DEG C, and calcination time is 4h.
Six, after mixed liquor Separation of Solid and Liquid, liquid is mainly acidic etching liquid body, in dioxygen oxidation process, reacts and has generated water with the hydrogen ion in system, and than former etching solution, the amount of water has risen. And in course of reaction, hydrochloric acid inevitably can volatilize, cause acid equivalent to reduce, so, in the process that enters etching working solution, need to supplement hydrochloric acid and ensure that acid equivalent is constant. And then make the water yield increase. So, filtrate is flowed in reverse osmosis membrane de-watering apparatus, too much water is removed.
Seven, filtrate flow in holding vessel, become for etched reuse liquid, and reuse liquid pipeline is linked on the pipeline that etching cylinder added water originally, adding this reuse liquid in etching cylinder by proportion management and control, some additives still add and carry out etching production according to acid equivalent management and control.
Embodiment 2
Composite (the g-C of photochemical catalyst/non-metal kind conductor3N4-TiO2Composite) preparation method as follows:
1, carbonitride (C3N4) preparation: by grinding after melamine calcining, obtain carbonitride (C3N4) pale yellow powder, calcining heat is 450 DEG C, calcination time is 4h.
2, take 1.0gC3N4Powder and 1.0gTiO2Powder by even both mixed grindings, is then put into hydrothermal reaction kettle by mixture in agate mortar, and after sealing, in Muffle furnace, 550 DEG C of reaction 4h(heating rates are 2.0 DEG C/min); Obtain g-C3N4-TiO2Composite.
Below in conjunction with drawings and Examples, the invention will be further described:
As shown in Figure 1, the technical scheme that in etching waste liquid of circuit board of the present invention, the recovery method of copper adopts comprises the steps:
One, in the etching cylinder of acidic etching liquid from production line with 2m3/ h flows out, and owing to not adding oxidant in this process, contains the univalent copper ion of 2g/L in etching solution. Acidic etching liquid to be regenerated flows in waste collection tank.
Two, acidic etching waste liquid flow in illumination oxidation reaction pond from waste collection tank, to adopt pressure be 5kg air compressor by air to add up to 10m3The speed of/h is pressed in system from 1000 holes, ensures to have larger contact area with acidic etching waste liquid. By g-C3N4-TiO2Composite joins in reaction tank by the consumption of 2mg/L, and adopts 400W strong illumination 2h. In this process, univalent copper ion is become bivalent cupric ion by airborne dioxygen oxidation, the hydrogen ion water generation reaction in oxygen and system.
Three, the acidic etching liquid that completes regeneration due to etching copper enter solution, cause the amount of copper in etching solution to raise compared with initial concentration. Now, by oxidation after acidic etching liquid with 2m3/ h flows in cation-exchange membrane sedimentation basin, and the consumption by 3g/L in sedimentation basin adds oxalic acid, obtains mixed liquor; Because oxalic acid is solid at normal temperatures, and can water-soluble release hydrogen ions and oxalate denominationby, the oxalate denominationby oxalic copper precipitation that combines with copper ion, because the amount of the copper precipitating in this process is very little than stoste, in cupric oxalate precipitation, the content of chlorion is also very little, can ignore. The hydrogen ion discharging in oxalic acid course of dissolution enters in system, replenishes the hydrogen ion consuming in oxidation step, keeps acidic etching liquid acid equivalent constant.
Four, mixed liquor enters and in tripod pendulum type batch centrifugal, carries out Separation of Solid and Liquid, and solid filter residue is mainly cupric oxalate precipitation, and filter residue is drawn off and collects pendingly, and copper content in filtrate will be reduced to 120g/L, i.e. the concentration of copper ion in original acidic etching liquid. The time of mix and blend precipitating reagent and acidic etching waste liquid is controlled at 60 minutes; The too short time causes precipitating insufficient, and crystallization is meticulous, and the long processing time is nonsensical.
Five, because the demand for cupric oxalate on market is also little, required by market, by soluble in water a part of filter residue, refilter the cupric oxalate obtaining after purification, now cupric oxalate content exceedes 99.9%, and sells with the form of this highly purified cupric oxalate; Another part resolves into active oxidation copper to be sold, and active oxidation copper gets by calcining highly purified cupric oxalate precipitation, and calcining heat is 500 DEG C, and calcination time is 3h.
Six, after mixed liquor Separation of Solid and Liquid, liquid is mainly acidic etching liquid body, in dioxygen oxidation process, reacts and has generated water with the hydrogen ion in system, and than former etching solution, the amount of water has risen. And in course of reaction, hydrochloric acid inevitably can volatilize, cause acid equivalent to reduce, so, in the process that enters etching working solution, need to supplement hydrochloric acid and ensure that acid equivalent is constant. And then make the water yield increase. So, filtrate is flowed in reverse osmosis membrane de-watering apparatus, too much water is removed.
Seven, filtrate flow in holding vessel, become for etched reuse liquid, and reuse liquid pipeline is linked on the pipeline that etching cylinder added water originally, adding this reuse liquid in etching cylinder by proportion management and control, some additives still add and carry out etching production according to acid equivalent management and control.
Embodiment 3
Composite (the mpg-C of photochemical catalyst/non-metal kind conductor3N4/ RGO composite) preparation method as follows:
(1) carbonitride (C3N4) preparation: by grinding after melamine calcining, obtain carbonitride (C3N4) pale yellow powder, calcining heat is 450 DEG C, calcination time is 4h.
(2)mpg-C3N4Preparation: by 12gC3N4In the molten silica aqueous solution that is 40% to 30g mass concentration of powder, and by mixed liquor evaporate to dryness. Obtain white powder and put into combustion boat, then send in tube furnace, under 300mL/min nitrogen protection, be warmed up to 550 DEG C with 2.3 DEG C/min, and maintain 4h at this temperature, naturally cool to room temperature. Obtain brown color powder, process 48h with 4mol/L ammonium hydrogen fluoride solution and remove template. Solution centrifugal after reaction is discarded to supernatant, use respectively deionized water and absolute ethanol washing, to remove the ion residues that may exist, in vacuum drying chamber, 60 DEG C of dried overnight, obtain faint yellow product, for subsequent use after grinding, and are labeled as mpg-C3N4
(3) preparation of GO:
(a) getting 2.5g graphite powder and 1.25g sodium nitrate, to be dissolved in 60ml mass concentration be in 95% the concentrated sulfuric acid, ice bath, and the time is 30min.
(b) add 7.5g potassium permanganate, under normal temperature, stir, mixing time is 12h.
(c) add the deionized water of 75ml, under high temperature, stir, temperature is 90 DEG C, and mixing time is 24h.
(d) adding while stirring 25ml mass concentration is 30% hydrogenperoxide steam generator again, obtains mixture.
(e) mixture is centrifugal, product, with dry after dilute hydrochloric acid solution and deionized water washing, obtains GO. Baking temperature is 60 DEG C. Watery hydrochloric acid mass concentration is 5%.
(4)mpg-C3N4The preparation of/RGO composite:
(a) the above-mentioned GO making is joined in the deionized water of 60ml to ultrasonic 1h.
(b) add again 0.5gmpg-C3N4, continue, after ultrasonic 30min, mixed liquor is stirred to 12h at normal temperatures.
(c) in mixed liquor, add 10ml methyl alcohol, under stirring, with 500W Xenon light shining 3h, make mpg-C3N4/ RGO composite.
Below in conjunction with drawings and Examples, the invention will be further described:
As shown in Figure 1, the technical scheme that in etching waste liquid of circuit board of the present invention, the recovery method of copper adopts comprises the steps:
One, in the etching cylinder of acidic etching liquid from production line with 2m3/ h flows out, and owing to not adding oxidant in this process, contains the univalent copper ion of 2g/L in etching solution. Acidic etching liquid to be regenerated flows in waste collection tank.
Two, acidic etching waste liquid flow in illumination oxidation reaction pond from waste collection tank, to adopt pressure be 5kg air compressor by air with 10m3The speed of/h is pressed in system from 1000 holes, ensures to have larger contact area with acidic etching waste liquid. By mpg-C3N4/ RGO composite joins in reaction tank by the consumption of 2mg/L, and adopts solar radiation 3h. In this process, univalent copper ion is become bivalent cupric ion by airborne dioxygen oxidation, the hydrogen ion water generation reaction in oxygen and system.
Three, the acidic etching liquid that completes regeneration due to etching copper enter solution, cause the amount of copper in etching solution to raise compared with initial concentration. Now, by oxidation after acidic etching liquid with 2m3/ h flows in cation-exchange membrane sedimentation basin, and the consumption by 3g/L in sedimentation basin adds oxalic acid, obtains mixed liquor; Because oxalic acid is solid at normal temperatures, and can water-soluble release hydrogen ions and oxalate denominationby, the oxalate denominationby oxalic copper precipitation that combines with copper ion, because the amount of the copper precipitating in this process is very little than stoste, in cupric oxalate precipitation, the content of chlorion is also very little, can ignore. The hydrogen ion discharging in oxalic acid course of dissolution enters in system, replenishes the hydrogen ion consuming in oxidation step, keeps acidic etching liquid acid equivalent constant.
Four, mixed liquor enters and in tripod pendulum type batch centrifugal, carries out Separation of Solid and Liquid, and solid filter residue is mainly cupric oxalate precipitation, and filter residue is drawn off and collects pendingly, and copper content in filtrate will be reduced to 120g/L, i.e. the concentration of copper ion in original acidic etching liquid. The time of mix and blend precipitating reagent and acidic etching waste liquid is controlled at 60 minutes; The too short time causes precipitating insufficient, and crystallization is meticulous, and the long processing time is nonsensical.
Five, because the demand for cupric oxalate on market is also little, required by market, by soluble in water a part of filter residue, refilter the cupric oxalate obtaining after purification, now cupric oxalate content exceedes 99.9%, and sells with the form of this highly purified cupric oxalate; Another part resolves into active oxidation copper to be sold, and active oxidation copper gets by calcining highly purified cupric oxalate precipitation, and calcining heat is 600 DEG C, and calcination time is 2h.
Six, after mixed liquor Separation of Solid and Liquid, liquid is mainly acidic etching liquid body, in dioxygen oxidation process, reacts and has generated water with the hydrogen ion in system, and than former etching solution, the amount of water has risen. And in course of reaction, hydrochloric acid inevitably can volatilize, cause acid equivalent to reduce, so, in the process that enters etching working solution, need to supplement hydrochloric acid and ensure that acid equivalent is constant. And then make the water yield increase. So, filtrate is flowed in reverse osmosis membrane de-watering apparatus, too much water is removed.
Seven, filtrate flow in holding vessel, become for etched reuse liquid, and reuse liquid pipeline is linked on the pipeline that etching cylinder added water originally, adding this reuse liquid in etching cylinder by proportion management and control, some additives still add and carry out etching production according to acid equivalent management and control.
The above is only preferred embodiments of the present invention, and the equivalence of doing according to the structure described in the scope of the invention, feature and principle therefore all changes or modifies, and is included in the scope of the invention.

Claims (10)

1. a method for photocatalysis PCB acidic etching liquid recycling, is characterized in that, concrete steps are as follows:
1) etching waste liquor overflowing in etching cylinder from production line flow in waste collection tank;
2) etching waste liquor flow into oxidation reaction pond from waste collection tank, the compressed system that enters of air, Cu+Ion is oxidized under the effect of porous photocatalytic agent and illumination;
3) oxidized waste liquid flows in sedimentation basin, adds precipitating reagent by the amount of the tolerance of solution simultaneously, under stirring action, precipitation reaction occurs, and forms and contains sedimentary mixed liquor;
4) mixed liquor enters and in tripod pendulum type batch centrifugal, carries out Separation of Solid and Liquid, and filter residue is drawn off and collects pendingly, and copper content in filtrate will be reduced to 80 ~ 160g/L;
5) according to market demand value, purify refining a part of filter residue, sell with the form of cupric oxalate; Another part resolves into active oxidation copper to be sold;
6) after mixed liquor Separation of Solid and Liquid, filtrate after supplementing hydrochloric acid is flowed in reverse osmosis membrane de-watering apparatus, too much water is removed, the amount of described too much water is step 2) in dioxygen oxidation process, the water adding while reacting the amount of the water that generates and supplementary hydrochloric acid with the hydrogen ion in system;
7) filtrate of flowing out in de-watering apparatus is flow in holding vessel, become for etched reuse liquid, and reuse liquid pipeline is linked on the pipeline that etching cylinder added water originally, add this reuse liquid in etching cylinder by proportion management and control, some additives still add and carry out etching production according to acid equivalent management and control.
2. the method that a kind of circuit board etching waste liquor circulating and recovering according to claim 1 and copper reclaim, is characterized in that, from the etching cylinder of etching production line, to flow out the flow velocity that enters into waste collection tank be 2 ~ 6m to etching waste liquor described in step 1)3/h。
3. the method that a kind of circuit board etching waste liquor circulating and recovering according to claim 1 and copper reclaim, is characterized in that step 2) flow velocity of described air is 10 ~ 20m3/ h, the intensity of illumination is 400 ~ 1000W.
4. the method that a kind of circuit board etching waste liquor circulating and recovering according to claim 1 and copper reclaim, is characterized in that step 2) described porous photocatalytic agent is the composite of photochemical catalyst/non-metal kind conductor.
5. the method that a kind of circuit board etching waste liquor circulating and recovering according to claim 4 and copper reclaim, is characterized in that, described photochemical catalyst is titanium dioxide or carbonitride; Described non-metal kind conductor is conductor Graphene, graphene oxide, redox graphene or the silane that is insoluble to strong acid.
6. the method that a kind of circuit board etching waste liquor circulating and recovering according to claim 1 and copper reclaim, is characterized in that step 2) the process spent time of described oxidation is 1 ~ 2h.
7. the method that a kind of circuit board etching waste liquor circulating and recovering according to claim 1 and copper reclaim, is characterized in that, the flow velocity of waste liquid is 2 ~ 6m described in step 3)3/h。
8. the method that a kind of circuit board etching waste liquor circulating and recovering according to claim 1 and copper reclaim, is characterized in that, the precipitating reagent described in step 3) is oxalic acid; Described mixing time is 15-90min.
9. the method that a kind of circuit board etching waste liquor circulating and recovering according to claim 1 and copper reclaim, is characterized in that, the sedimentation basin described in step 3) is cation-exchange membrane sedimentation basin.
10. the method that a kind of circuit board etching waste liquor circulating and recovering according to claim 1 and copper reclaim, is characterized in that, the active oxidation copper described in step 5) is by calcining cupric oxalate precipitation and getting.
CN201610162230.7A 2016-03-20 2016-03-20 A kind of method of photocatalysis PCB acidic etching liquid recyclings Expired - Fee Related CN105603434B (en)

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