CN111032917B

CN111032917B - Ammonia distillation recycling process and system for alkaline etching waste liquid of circuit board

Info

Publication number: CN111032917B
Application number: CN201880035101.9A
Authority: CN
Inventors: 叶涛
Original assignee: Individual
Current assignee: Individual
Priority date: 2017-07-05
Filing date: 2018-07-05
Publication date: 2021-06-15
Anticipated expiration: 2038-07-05
Also published as: CN108149249A; CN111032917A; WO2019007407A1

Abstract

A process for recycling ammonia distillation of alkaline etching waste liquid of a circuit board comprises the steps of heating the alkaline etching waste liquid, and collecting gas generated in the heating process to obtain waste liquid gas; when the etching waste liquid is heated until a precipitate is separated out, a solid-liquid mixture A1 is obtained; mixing the solid-liquid mixture A1 with hydrochloric acid and/or acidic etching waste liquid and adjusting the pH, and separating insoluble precipitate from other soluble components; obtaining mixed solution A2; mixing the waste liquid gas with carbon dioxide to generate ammonium carbonate and/or ammonium bicarbonate; adding ammonium carbonate and/or ammonium bicarbonate into the mixed solution A2 and supplementing other components required by the etching process to obtain a recycled etching solution, wherein foreign substances which are bad for etching are not brought in the treatment process, so that the recycling can be realized, the production cost can be effectively reduced, and the problem of ammonia nitrogen pollution brought by the traditional alkaline copper chloride ammonium etching waste liquid extraction and recovery process is solved; also discloses an ammonia distillation recovery and circulation process system for the alkaline etching waste liquid of the circuit board.

Description

Ammonia distillation recycling process and system for alkaline etching waste liquid of circuit board

Technical Field

The invention relates to the field of waste etching solution recycling, in particular to an ammonia distillation recycling process for alkaline waste etching solution of a circuit board.

Background

Etching is an important step in the existing Printed Circuit Board (PCB) manufacturing process. Etching is to remove unnecessary copper on the copper-clad substrate by chemical reaction with an etching solution to form a desired circuit pattern.

The commonly used etching solution at present comprises acidic copper chloride and alkaline ammonium copper chloride, wherein:

the acidic copper chloride etching solution mainly comprises the following components: copper salts, hydrochloric acid, sodium chloride or ammonium chloride, water, and optionally additives.

The main components of the alkaline ammonium copper chloride etching solution are copper salt, ammonium chloride, ammonia water, optional carbonate and optional additives; among them, ammonium carbonate and ammonium bicarbonate are generally used as the carbonate. When a PCB is etched using an alkaline ammonium copper chloride etchant, the etchant is usually added to maintain a concentration balance of the components during the etching process. The main components of the etching sub-solution are ammonium chloride, ammonia water, optional carbonate and optional additives.

The optional additives in the etching solution and the etching sub-solution refer to some optional additives which have certain optimization effect on the performance of the etching solution (such as changing reaction balance and reaction rate) and do not change main chemical reaction generated in the etching process. Such as stabilizers, accelerators, and the like.

The following reaction occurs when etching is performed using basic ammonium copper chloride:

Cu(NH₃)₄Cl₂+Cu→2Cu(NH₃)₂Cl

4Cu(NH₃)₂Cl+4NH₄Cl+4NH₄OH+O₂→4Cu(NH₃)₄Cl₂+6H₂O

since the alkaline ammonium copper chloride etching solution reacts continuously during the etching process, the components of the etching solution are consumed continuously, and the concentration of the components of the etching solution changes continuously, and generally, the component content of the etching sub-solution is slightly higher than the concentration of the corresponding components in the etching solution. The concentration of copper ions is required to be controlled within 30-180g/l and the pH value is required to be within 7-9 in the etching process, so that the component content in the etching solution is required to be continuously detected by an automatic detection feeding control machine in the production process, and the etching solution and/or the supplemented ammonia water are added according to the detection condition.

In the actual production, in order to keep the components of the etching solution stable, the etching solution in the etching tank is inevitably increased and overflows out of the etching tank because the etching solution and/or the ammonia water are required to be continuously added; the etching solution overflowing out of the etching bath or the used etching solution is generally called as etching waste solution, the main components of the alkaline ammonium copper chloride etching waste solution comprise ammonium copper chloride, cuprous ammonium chloride, ammonium chloride and ammonia water, and some alkaline etching waste solutions also contain ammonium carbonate, ammonium bicarbonate, organic ammonium salt, organic amine and the like.

The following three common treatment methods for alkaline etching waste liquid exist at present:

an acidification electrolysis method: carrying out acidification reaction on the alkaline etching waste liquid by using hydrochloric acid and/or acidic copper chloride etching waste liquid to generate precipitate and supernatant; the separated precipitate is dissolved by sulfuric acid to prepare copper sulfate or electrolyzed to prepare refined copper, and the supernatant and the copper sulfate-containing residual liquid generated in the copper sulfate preparation process are subjected to evaporation concentration after further copper removal to obtain the mixed ammonium salt. The main components of the existing acidic copper chloride etching waste liquid generally comprise hydrochloric acid, copper chloride, cuprous chloride and water.

The method has the disadvantages that sulfuric acid is used in the recovery treatment process, sulfate radicals which have aggressive corrosivity to an etching resisting layer are introduced, and the produced mixed ammonium salt can not be reused in the etching process; and the energy consumption for preparing the mixed ammonium salt by applying the evaporation and concentration process is large.

An alkalization method: and adding a sodium hydroxide solution into the alkaline etching waste liquid, and heating to obtain copper oxide precipitate. Then dissolving the copper oxide precipitate with sulfuric acid to obtain copper sulfate, and absorbing the ammonia gas escaped in the heating process with water to obtain ammonia water for recycling. The residual liquid is treated to reach the discharge standard before being discharged.

The method has the defects of large wastewater treatment capacity and high treatment cost after the copper oxide and the ammonia water are recovered.

An extraction electrolysis method: after the alkaline etching waste liquid and the organic extractant are mixed and phase-separated, the sulfuric acid is used for back extraction to obtain copper sulfate, and the copper sulfate solution is electrolyzed to obtain the refined copper. Part of the waste liquid after the phase separation treatment can be prepared into etching solution again for recycling.

The method uses the organic extractant in the recovery process, and has the defects that when the etching solution is recovered and recycled to prepare the etching solution again, a small amount of the organic extractant is mixed every time, and the indexes of the etching rate and the quality are reduced after accumulation. In addition, the extraction agent process causes ammonia nitrogen pollution in the recovery process, and the treatment cost is higher.

The ammonia nitrogen pollutants are very easy to dissolve in water, the ammonia nitrogen content index in the water body is an important index of water body eutrophication, once the water body is eutrophicated, algae in the water body are very easy to propagate massively to explode red tide and water bloom, on one hand, the oxygen content of the water body is reduced, and other organisms (fish, shrimp, crab and the like) in the water body die due to oxygen deficiency, so that the water body is polluted; on the other hand, the accumulation of toxins produced by toxic algae can directly cause water body pollution.

In summary, although the existing three treatment methods for alkaline etching waste liquid can recover copper sulfate, refined copper, ammonium salt or ammonia water from the waste liquid, some of the treatment methods can also make the alkaline etching waste liquid re-prepared into etching sub-liquid for recycling, in the process of recycling the alkaline etching waste liquid, foreign substances which are bad for etching can be brought in, the indexes of etching rate and quality are affected, and the problem of ammonia nitrogen pollution is brought, or the treatment cost is high, no treatment method can recycle the alkaline etching waste liquid well, the production cost can be effectively reduced, and the problem of ammonia nitrogen pollution brought by the traditional alkaline ammonium copper chloride extraction electrolysis recovery process can be solved.

Disclosure of Invention

The invention aims to provide an ammonia distillation recovery and circulation process for alkaline etching waste liquid of a circuit board, which not only can recover and recycle the alkaline etching waste liquid, but also can keep the normal etching rate and quality index of the recycled etching sub-liquid obtained by recovery; and the problem of ammonia nitrogen pollution can not be caused.

The purpose of the invention can be realized by adopting the following technical scheme:

an ammonia distillation recycling process for alkaline etching waste liquid of a circuit board comprises the following steps:

(1) gas-liquid separation of etching waste liquid: heating the alkaline etching waste liquid with the copper ion concentration of 30-180g/L, pH value of 7-9, collecting gas generated in the heating process, and obtaining waste liquid distilled gas A; when the etching waste liquid is heated until a precipitate is separated out, a solid-liquid mixture A1 is obtained;

in step 2, more basic copper chloride is generated through the reaction formula in the acidification process, so that the amount of precipitates is increased. In general, both steps will have precipitates generated.

(2) Adjusting the pH value: mixing the solid-liquid mixture A1 obtained in the step (1) with hydrochloric acid and/or acidic etching waste liquid, adjusting the pH value to 3-6, further increasing precipitates in the solid-liquid mixture A1, separating the precipitates in the obtained solid-liquid mixture A1, and respectively obtaining solid precipitates and a mixed solution A2 after solid-liquid separation;

(3) and (3) gas treatment: mixing the waste liquid distilled gas A collected in the step (1) with carbon dioxide to generate ammonium carbonate and/or ammonium bicarbonate;

(4) mixing the solution: adding ammonium carbonate and/or ammonium bicarbonate into the mixed solution A2 obtained in the step 2 to obtain a mixed solution A3;

(5) regeneration of etching solution: and (4) supplementing other required components of the etching process in the mixed solution A3 obtained in the step (4) to obtain the etching solution for recycling.

In the heating process of the step (1), the generated gas comprises ammonia gas, water vapor and carbon dioxide which may be generated; the ammonia gas is derived from ammonia water volatilization contained in the etching waste liquid and decomposition or hydrolysis reaction of ammonium carbonate, ammonium bicarbonate, organic amine, organic ammonium and other components contained in part of alkaline etching liquid. The carbon dioxide comes from the decomposition reaction of ammonium carbonate and/or ammonium bicarbonate contained in the etching waste liquid by heating; the water vapor is derived from the evaporation of liquid water;

see in particular the chemical reaction formulae below.

The chemical reaction that takes place in step (1) is as follows:

volatilization reaction of ammonia water:NH₄OH→H₂O+NH₃↑

thermal decomposition reaction of ammonium carbonate: (NH)₄)₂CO₃→2NH₃↑+CO₂+H₂O

Thermal decomposition reaction of ammonium bicarbonate: NH (NH)₄HCO₃→NH₃↑+CO₂+H₂O

Thermal decomposition reaction of organic ammonium salt: R-NH₄→NH₃↑+R-H

And (3) carrying out a heated hydrolysis reaction on organic amine: R-NH₂+H₂O→NH₃↑+R-OH

The main components of the solid-liquid mixture A1 in the step (1) comprise cupric ammonium chloride, cuprous ammonium chloride, ammonia water, basic cupric chloride and cupric hydroxide. Wherein, the cupric ammonium chloride, cuprous ammonium chloride, ammonium chloride and ammonia water are the original main components of the alkaline etching waste liquid, and the basic cupric chloride and the cupric hydroxide are from the sources, because the cupric chloride is soluble only in the acidity, and becomes the basic cupric chloride Cu when becoming neutral or alkaline along with the reduction of the acidity₂(OH)₂Cl₂And/or copper hydroxide Cu (OH)₂But is hardly soluble in water, and the nitrogen atom of ammonia has lone electron pair and can form hydrogen bond with water molecule, so that the copper of copper chloride and NH3 form complex copper chloride ammonia Cu (NH)₃)₄Cl₂When dissolved in water. Therefore, in the step 1, since part of the ammonia gas and part of the water in the solution are evaporated as one of the components of the gas a, the solution does not have enough ammonia to complex with the copper chloride, and the water as the solvent is reduced, so that the precipitate of copper oxychloride and/or copper hydroxide occurs, and the solid-liquid mixture a1 is obtained:

2Cu(NH₃)₄Cl₂+2H₂O→Cu₂(OH)₂Cl₂+2NH₄Cl+6NH₃↑

Cu(NH₃)₄Cl₂+2H₂O→Cu(OH)₂+2NH₄Cl+2NH₃↑

the main chemical equation of the reaction of the solid-liquid mixture A1 and hydrochloric acid in the step (2) is as follows:

2Cu(NH₃)₄Cl₂+2HCl+2H₂O→Cu₂(OH)₂Cl₂↓+4NH₄Cl

4Cu(NH₃)₂Cl+8HCl+4H₂O+O₂→2Cu₂(OH)₂Cl₂↓+8NH₄Cl+2H₂O

2Cu(OH)₂+2HCl→Cu₂(OH)₂Cl₂↓+2H₂O

NH₄OH+HCl→NH₄Cl+H2O

Cu₂(OH)₂Cl₂+4HCl→2CuCl₂+4H₂O

from the above reaction formulae, in the present invention, when the solid-liquid mixture a1 is reacted with hydrochloric acid alone, the mixed solution a2 in the step (2) contains ammonium chloride and water as main components, and may contain copper chloride formed by the reaction with sufficient hydrochloric acid and residual unreacted copper ammonium chloride, cuprous ammonium chloride, and hydrochloric acid.

On the other hand, in the step (2), if the solid-liquid mixture a1 reacts only with the acidic etching waste liquid, since the acidic etching waste liquid is a waste liquid generated after the etching operation of the acidic copper chloride etching liquid and contains hydrochloric acid, copper chloride, cuprous chloride and water as main components, the following reactions occur in addition to the reaction of each of ammonium cupric chloride, ammonium cuprous chloride, aqueous ammonia and copper hydroxide in the solid-liquid mixture a1 with hydrochloric acid in the acidic etching waste liquid:

Cu(OH)₂+CuCl₂→Cu₂(OH)₂Cl₂↓

4NH₄OH+CuCl₂→Cu(NH₃)₄Cl₂+4H₂O

Cu₂Cl₂+4NH₄OH→2Cu(NH₃)₂Cl+4H₂O

therefore, when the solid-liquid mixture a1 reacts with the acidic etching waste liquid, the mixed solution a2 described in step (2) contains ammonium chloride and water as main components, and may contain ammonium cupric chloride, ammonium cuprous chloride, cupric chloride, cuprous chloride, and hydrochloric acid.

The solid precipitate separated in the step (2) mainly comprises basic copper chloride and/or copper hydroxide, and may also contain ammonium chloride which is not dissolved due to insufficient water in the solid-liquid mixture A1, and can be washed to form basic copper chloride and/or copper hydroxide for packaging and sale, or can be mixed with a sodium hydroxide solution and heated to form a copper oxide product for sale.

In the step (3) of the present invention, the ammonia gas in the gas reacts with the carbon dioxide and the water vapor as follows:

2NH₃+CO₂+H₂O→(NH₄)₂CO₃

NH₃+CO₂+H₂O→NH₄HCO₃

the carbon dioxide in the step (3) of the present invention may be ammonium carbonate or ammonium bicarbonate which is derived from the thermal decomposition of the etching waste liquid in the step (1), may be an additional carbon dioxide gas, or may be a combination of the two.

The ammonium carbonate and/or ammonium bicarbonate added in the step (4) in the invention in the A2 can be purchased, or can be derived from the ammonium carbonate and/or ammonium bicarbonate obtained in the step (3), or can be a combination of the ammonium carbonate and the ammonium bicarbonate; the obtained mixed solution a3 mainly contains the following components: cupric ammonium chloride, cuprous ammonium chloride, ammonium carbonate, and/or ammonium bicarbonate.

The invention utilizes the characteristic that ammonium carbonate and ammonium bicarbonate are decomposed by heat to generate ammonia, and takes the ammonium carbonate and/or the ammonium bicarbonate as etched NH₄ ⁺Dissolving the source, preferably ammonium carbonate and ammonium bicarbonate obtained from the step (3), in the mixed solution A2 to prepare the etching sub-solution for recycling, and effectively providing NH in the etching process₄ ⁺And the amount of extra added ammonia water is reduced. Thereby ensuring that the volume of the recycled etching solution obtained after the recovery treatment of the invention is not larger than the supplement addition amount of the etching solution required by etching production, and ensuring that the recycling process does not generate circulationThe surplus of the etching solution is too much to consume.

Supplementing other required components of the etching process in the mixed solution A3 in the step (5) of the invention means supplementing ammonium chloride, ammonia water, optional carbonate and optional additives which are contained in the original etching sub-solution, but are consumed by reaction in the etching process and are not regenerated or insufficient in regeneration amount in the recovery process, so that the ammonium ion concentration, the ammonium chloride concentration and the optional additive concentration of the etching sub-solution which is recycled are not lower than the ammonium ion concentration, the ammonium chloride concentration and the optional additive concentration of the etching sub-solution when an etching waste solution recovery system is not used; wherein the supplemented ammonia water can be replaced by ammonium carbonate and/or ammonium bicarbonate as long as NH is maintained⁴⁺The ion concentration is equivalent.

The etching solution recycled in the step (5) of the invention replaces part or all of the etching solution without using a recovery system to be supplemented in the etching solution in the etching operation process. When an automatic detection feeding control machine is used in the production process, the pH value and/or specific gravity parameter value of the etching solution is automatically detected through the automatic detection feeding control machine, and the etching solution is automatically controlled to be fed for recycling according to a set value.

The invention can be further improved as follows:

in order to better recycle the etching waste liquid, when the mixed solution A2 is used to dissolve the ammonium carbonate and/or ammonium bicarbonate obtained in the step (3) in the step (4), the mixed solution A2 obtained by filtering in the step (2) can be directly used for washing and dissolving the ammonium carbonate and/or ammonium bicarbonate, namely, the mixed solution A2 is directly used for washing a production container of the ammonium carbonate and/or ammonium bicarbonate to carry the ammonium carbonate and/or ammonium bicarbonate away, and then the step (5) is carried out.

As can be seen from the ammonia and carbon dioxide reaction equation, when the mass concentration of the carbon dioxide species is lower than that of the ammonia species, the reaction equilibrium tends to produce ammonium carbonate; conversely, the reaction equilibrium will tend to produce ammonium bicarbonate; the quantity and concentration proportion of different substances can be set, and the quantity of the obtained ammonium carbonate and ammonium bicarbonate can be controlled. Thus, in step (3), the gas reaction can be divided into the following two parts: the method comprises the following steps of firstly, enabling the quantity concentration of a first part of ammonia gas to be larger than that of a carbon dioxide substance, and secondly, enabling the quantity concentration of a second part of ammonia gas to be smaller than that of the carbon dioxide substance, so as to control the proportion of generated ammonium carbonate and ammonium bicarbonate. Namely, the gas can be firstly subjected to the reaction that the quantity concentration of the ammonia gas is greater than that of the carbon dioxide substance, and then the residual unreacted gas is subjected to the reaction that the quantity concentration of the ammonia gas is less than that of the carbon dioxide substance; the gas may be first divided into two parts and the reaction may be carried out in which the concentration of the ammonia gas is higher than that of the carbon dioxide and the reaction in which the concentration of the ammonia gas is lower than that of the carbon dioxide. Ammonium carbonate is beneficial to stable etching in the etching process, and ammonium bicarbonate is beneficial to reducing pollution caused by ammonia tail gas exhaust at the outlet of the chemical combination reaction tank.

In order to better recycle the etching waste liquid, in the step (3), a jet device can be adopted for collecting tail gas of the synthesis reaction of ammonium carbonate and/or ammonium bicarbonate, water is used as jet liquid absorption gas, and the ammonium carbonate and/or ammonium bicarbonate aqueous solution recovered in the jet device can be reused for preparing the etching sub-liquid.

In order to better recycle the etching waste liquid, in the step (3), a jet device is adopted to use water as jet liquid to absorb tail gas of the synthesis reaction of ammonium carbonate and/or ammonium bicarbonate, and a pH meter is adopted to detect the pH value of an aqueous solution obtained in the jet device; when the aqueous solution is detected to be alkaline, the amount of carbon dioxide in the synthesis reaction of ammonium carbonate and/or ammonium bicarbonate is appropriately increased; otherwise, the amount of carbon dioxide is appropriately reduced.

To facilitate the escape of gas from the mixing location, collection is facilitated. In the step (1), a stirring device can be used in the heating process.

In order to accelerate the gas-liquid separation of the etching waste liquid in the step (1), an external pressurized air insertion pipe is arranged on the heating container and is opened during and/or after the heating process is finished. The external pressurized air insertion pipe comprises a pipeline and a pump which are communicated with the heating container and the outside.

And (3) opening the external pressurized air insertion pipe in the heating process, pumping the air outside the heating container into the heating container through the external pressurized air insertion pipe, stirring the mixture in the heating container, and simultaneously promoting the volatilized gas of the mixture to rapidly enter the step (3) for synthesis reaction.

And after the heating process is finished, the external pressurized air insertion pipe is opened, so that the air outside the heating container can be pumped into the heating container through the external pressurized air insertion pipe, and the temperature of the mixture in the heating container is reduced at an accelerated speed while stirring, so that the next step is carried out as soon as possible.

The second object of the present invention can be solved by the following technical solutions:

a system for recovering and circulating ammonia from alkaline etching waste liquor of a circuit board comprises the following components:

the acid-base adjusting tank is used for adjusting the pH value of the residual liquid after the alkaline etching waste liquid is evaporated;

the heating evaporation tank is provided with a heating device and an air outlet which are arranged inside and/or outside the heating evaporation tank; for concentrating and heating the alkaline etching waste liquid and separating the waste liquid gas;

a chemical combination reaction tank provided with a carbon dioxide inlet and a waste liquid gas inlet; the carbon dioxide inlet is connected with a carbon dioxide source; for the manufacture of ammonium carbonate and/or ammonium bicarbonate;

the filter is connected with the acid-base adjusting tank; for separating solids and liquids in a solid-liquid mixture;

and the seed solution preparing tank is used for preparing the etching seed solution for recycling.

Preferably, a stirring device is arranged in the heating evaporation tank.

Preferably, the heating evaporation groove is provided with an external pressurized air insertion pipe; the external pressurized air insertion pipe is composed of a pipeline and a pump, wherein the pipeline is communicated with the inside of the heating evaporation groove and the outside.

Preferably, a pump is arranged on a pipeline connecting the heating evaporation tank and the chemical combination reaction tank and/or an air outlet of the chemical combination reaction tank.

Preferably, the combination reaction tank is provided with an additional air outlet and/or an additional liquid inlet and/or a discharge outlet.

One of the additional gas outlets functions as a gas outlet when interconnecting the chemical combination reaction tank with other chemical combination reaction tanks or a jet device; and the other function is to effectively prevent potential safety hazard caused by overlarge air pressure in the chemical combination reaction tank.

The additional liquid inlet is an inlet for directly entering the mixed solution A2 into the chemical combination reaction tank after passing through the filter. Since the production of ammonium carbonate and/or ammonium hydrogencarbonate is stopped when the mixed solution A2 is fed into the chemical combination reaction tank through the filter, the carbon dioxide inlet and/or the waste liquid gas inlet of the chemical combination reaction tank can also be used as the liquid inlet as it is.

The discharge port is an outlet for conveying ammonium carbonate and/or ammonium bicarbonate in the combination reaction tank to the sub-liquid preparation tank (whether the mixed solution A2 passes through the combination reaction tank or not is not considered at this time, and the discharge port is required for conveying the ammonium carbonate and/or the ammonium bicarbonate no matter whether the mixed solution A2 does not pass through the combination reaction tank or whether the mixed solution A2 washes and dissolves the ammonium carbonate and/or the ammonium bicarbonate insufficiently). Since the production of ammonium carbonate and/or ammonium bicarbonate has been stopped when transporting ammonium carbonate and/or ammonium bicarbonate out of the combination reaction tank, the carbon dioxide inlet and/or the waste liquid gas inlet of the combination reaction tank may also be used as the discharge port as it is.

More preferably, a heating device is provided near the carbon dioxide inlet and/or the waste liquid gas inlet and/or the liquid inlet of the chemical combination reaction tank.

The heating device is arranged near the carbon dioxide inlet and/or the waste liquid gas inlet and/or the liquid inlet of the combination reaction tank, so that the positions can be kept at higher temperature, the generation speed of solid ammonium carbonate and/or ammonium bicarbonate can be effectively inhibited, and the inlets can be prevented from being blocked.

Preferably, the chemical combination reaction tank is connected with a jet device;

the jet flow vacuum device is provided with a gas-liquid mixing cavity and a collecting cylinder, and water is stored in the collecting cylinder and used for dissolving tail gas of the chemical combination reaction tank;

the gas-liquid mixing cavity is respectively provided with a jet air suction port, a jet liquid inlet and a jet liquid outlet, and the jet liquid outlet extends into the collecting cylinder through a liquid outlet pipe; the jet liquid inlet is connected with the collecting cylinder through an absorption liquid circulating pipe and a liquid inlet pump arranged on the pipeline.

Preferably, a pH meter is arranged in the collecting cylinder of the fluidic device and is used for detecting the pH value of the liquid in the collecting cylinder.

The invention has the beneficial effects that:

1) in the process of treating the alkaline ammonium copper chloride etching waste liquid, no new impurities such as acid radical ions and the like are introduced, and no organic extractant is contained, so that the alkaline ammonium copper chloride etching waste liquid is recycled, the etching waste liquid is recycled into the etching sub-liquid, and the etching sub-liquid is recycled in the etching process.

2) The recycled etching solution obtained by recycling does not contain an organic extractant, so that not only can the normal etching rate and quality index be maintained, but also ammonia nitrogen pollution is avoided.

3) The invention uses NH in the alkaline ammonium copper chloride etching waste liquid⁴⁺The quality requirement can be met without or only by adding a small amount of ammonia water when preparing the etching solution for recycling, so that the volume change of the etching solution is extremely small, a large amount of residual etching solution can not be generated in the using process, the amount of the etching solution overflowing from the etching tank is reduced, and unnecessary energy consumption is avoided.

4) The invention can recover NH in the alkaline ammonium copper chloride etching waste liquid⁴⁺The problem that ammonia nitrogen pollutants are discharged to the environment by the traditional alkaline copper ammonium chloride etching waste liquid is solved.

Drawings

FIG. 1 is a flow chart of a recycling process of waste etching solution according to a first embodiment of the present invention;

FIG. 2 is a flow chart of the recycling process of the waste etching solution according to the second embodiment of the present invention;

FIG. 3 is a flow chart of the recycling process of the etching waste liquid in the third embodiment of the present invention;

FIG. 4 is a flow chart of the recycling process of the waste etching solution in the fourth embodiment of the present invention;

FIG. 5 is a flow chart of the recycling process of the waste etching solution according to the fifth embodiment of the present invention;

FIG. 6 is a flow chart of the recycling process of the waste etching solution according to the sixth embodiment of the present invention.

Detailed Description

The present invention is further described in the following with reference to the drawings and examples so that those skilled in the art can better understand the present invention and can practice it, but the examples are not intended to limit the present invention.

In the following examples and comparative examples, ammonium chloride used was ammonium chloride produced by Guangzhou chemical industries; the ammonia water used is the ammonia water produced by Guangzhou chemical reagent factory; the copper chloride is CuCl produced by Guangzhou chemical reagent factory₂·2H₂O (more than or equal to 99.0%); the ammonium carbonate used is ammonium carbonate produced by Shanghai Hengyuan biological technology limited; the used ammonium bicarbonate is the ammonium bicarbonate produced by Shanghai lanke medicine science and technology development company Limited; the used alkaline etching solution additives are YH-302, YH-303 and YH-304 alkaline etching additives produced by Guangzhou high-chemical industry Co., Ltd; the used automatic detection feeding control machine is an industry high PCB alkaline etching automatic feeding control machine-2 type (alkaline copper chloride etching system) produced by Guangzhou city industry high chemical industry limited company; the used alkaline etching waste liquid comes from Guangzhou high chemical industry Co Ltd; the acidic waste etching solution used is from Guangzhou high chemical industry Co.

In addition to those enumerated above, those skilled in the art can select other products having similar properties to those enumerated above in the present invention according to routine selection, and can achieve the objects of the present invention.

The alkaline etching waste liquid of example 1 was prepared as follows:

step 1: at normal temperature and normal pressure, respectively according to the components specified in the etching solution circularly reused in the following table 1, dissolving the selected raw materials in water to prepare the etching solution;

step 2: copper chloride was added per liter of the etchant solution obtained in step 1. The addition amount of copper chloride is calculated according to the set value of the concentration of copper ions in the solution listed in table 1:

wherein the molar mass of the copper chloride is 134.5 g/mol; the molar mass of the copper ions is 63.5 g/mol; according to the values specified in example 1 of Table 1, 190.6g of copper chloride were added per liter of etching bath.

And step 3: pouring the solution obtained in the step (2) into an etching cylinder, and immersing a detection probe for automatically detecting each parameter of the feeding control machine into the etching solution;

and 4, step 4: pouring the etching solution obtained in the step (1) into an etching solution tank connected with a specific gravity meter in an automatic detection and feeding control machine. The temperature of the etching cylinder was set to 50 ℃ and the pressure of the etching solution nozzle of the etching machine was set to 2kg/cm²；

And 5: the etching operation was started, and the automatic detection and feed controller automatically fed the etchant solution to replenish the components in the equilibrium etchant solution so that the specific gravity was maintained at the specific gravity value specified in table 1. In the etching process, the pH value of the etching solution is detected by the automatic detection feeding controller, and the detected value is recorded in the table 1;

step 6: carrying out an etching rate and an etching factor K test on the etching solution, and recording the result in the table 1; the etching working solution after completion of the etching test was used as an alkaline etching waste solution to continue the procedure of the following example.

Etching quality test

An etching factor test circuit board with the size of 620 multiplied by 540mm, the copper thickness of 1oz and the development line width line spacing of 50.8 mu m and a pure copper etching rate test board with the size of 500 multiplied by 300mm multiplied by 1.5mm are put into an etching machine for spray corrosion test, and the etching rate and the etching factor K are calculated by using a method (printed circuit technology, Lexuming, the center for guidance of professional skill identification in the electronic industry of the industry and the informatization department, fifth edition, p 387-389), metallic corrosion theory and application, Weibaoming, chemical industry publishing company, p5-7, shallow etching factor calculation method, Tianling and the like, printed circuit information 2007No.12, p55-56) known in the industry. The results of the calculation of the etching rate and the etching factor K are shown in table 2.

The alkaline etching waste liquid of example 2 was prepared as follows:

the etching solution used in the preparation process of the alkaline etching waste solution of example 2 comprises the following components: 20 wt% of ammonium chloride, 21 wt% of ammonia water, 10 wt% of additive and the balance of water. The pH control parameter of the automatic detection and feeding control machine is 7.2, the specific gravity is controlled to be 1.31g/ml, the copper ion concentration parameter is shown in the following table 1, and the method for preparing the alkaline etching waste liquid in the example 1 is repeated.

The etching quality test was carried out as described for the preparation of alkaline etching waste liquor in example 1.

The contents of the components of the etchant solution in the process of preparing the alkaline etching waste solution of examples 3 to 20 are the same as the contents of the components of the etchant solution recycled in table 1, and the method for preparing the alkaline etching waste solution of example 1 is repeated with reference to the parameters of the automatic detection batch controller listed in table 1 below.

Example 1

(1) As shown in fig. 1, a heating device is arranged in the heating evaporation tank, the alkaline etching waste liquid with the parameters in table 1 is heated to boiling in the heating evaporation tank for evaporation, and after the alkaline etching waste liquid is concentrated for 12 hours until precipitates are separated out by naked eyes, a solid-liquid mixture A1 is obtained and is pumped into the acid-base adjustment tank; collecting and introducing gas escaped in the heating process into a combination reaction tank, carrying out chemical reaction by enabling the carbon dioxide amount concentration of the combination reaction tank to be higher than the ammonia gas amount concentration under the condition of adjusting the concentration of the externally-added carbon dioxide compressed gas, and keeping the molar concentration ratio of the carbon dioxide to the ammonia gas to be about 2:1 to obtain ammonium bicarbonate;

(2) pouring the A1 solid-liquid mixture and hydrochloric acid into an acid-base adjusting tank, mixing and adjusting the pH value to 3, and filtering by a filter to obtain solid basic copper chloride and a mixed solution A2;

(3) scraping the ammonium bicarbonate obtained in the step (1) from a chemical reaction tank, dissolving the ammonium bicarbonate into an A3 mixed solution by using an A2 solution, draining the mixed solution into a seed solution preparation tank, and measuring and calculating the concentration of each component in the A3 mixed solution by using a method known in the industry (determination of ammonia and carbon dioxide in chemical raw materials ammonium carbonate, plum blossom, metallurgical analysis, Vol.24 No.1, p78-79, synthetic hydrochloric acid for GB320-2006 industry, national Committee of standardization management, p2-3, research on chloride ion measurement method and application thereof, Shulingyun, etc., Western leather Vol.31 No.15, p32-42) and an additive using a detection method in an instruction book;

(4) and adding and supplementing the lacked chemical raw materials into the A3 mixed solution in an auxiliary solution preparation tank according to the component proportion of the recycled auxiliary solution required by the etching process in the table 1 to prepare the recycled etching auxiliary solution (the copper ion concentration in the A3 mixed solution does not need to be considered during preparation, the concentration of other components only needs to reach the set standard, and the rest examples are the same). The prepared recycled etching sub-liquid is automatically detected by an automatic detection feeding control machine according to specific gravity parameters in the table 1, added to an etching production line for etching working procedures, and the etching quality test is carried out according to the method for preparing the alkaline etching waste liquid. And the etching rate and the etching factor K are shown in table 1.

Example 2

(1) As shown in fig. 2, heating devices are arranged inside and outside the heating evaporation tank, the heating evaporation tank provided with an external pressurized air insertion pipe and a motor-driven stirring device is used for heating the alkaline etching waste liquid with the parameters in the table 1 to boiling for evaporation, the external pressurized air insertion pipe is opened to drive external air into the heating evaporation tank for stirring the mixture in the tank, the heating is stopped after the concentration is carried out for 1 hour until precipitates are separated out by naked eyes, and the external pressurized air insertion pipe continues to work for carrying out accelerated cooling on the heating evaporation tank; obtaining A1 solid-liquid mixture and pumping the solid-liquid mixture into an acid-base adjusting tank; collecting and introducing gas escaped in the heating process into the first combination reaction tank;

(2) the first combined reaction tank is communicated with a second combined reaction tank which is provided with a jet device for conducting tail gas guiding and collecting treatment; under the regulation of the concentration of the externally added carbon dioxide compressed gas, the ratio of the concentration of ammonia gas to the concentration of carbon dioxide in the first combination reaction tank is about 6:1 to obtain ammonium carbonate through reaction, the concentration of carbon dioxide in the second combination reaction tank is higher than the concentration of ammonia gas, and the molar concentration ratio of carbon dioxide to ammonia gas is kept to be about 1.5:1 to obtain ammonium bicarbonate through reaction; the tail gas of the second combination reaction tank is mixed with water for absorption through a connected jet device;

(3) pouring the A1 solid-liquid mixture and the circuit board acidic etching waste liquid into an acid-base adjusting tank to be mixed and adjust the pH value to 6, filtering by a filter to obtain solid basic copper chloride, and simultaneously flushing a first and a second combined reaction tanks by using a filtrate A2 by using filtering pressure to take the ammonium carbonate and the ammonium bicarbonate obtained in the step (1) out of the tanks to obtain an A3 mixed solution; then draining the liquid into the sub-liquid preparation tank;

(4) and (3) adding the aqueous solution obtained by supplementing the jet device in the step (1) and other required components into the A3 mixed solution according to the component proportion of the recycled etching solution required by the etching process in the table 1 in an etching solution preparation tank to prepare the recycled etching solution. The prepared recycled etching sub-liquid is automatically detected by an automatic detection feeding control machine according to specific gravity parameters and pH parameters in the table 1 and is fed on an etching production line for etching working procedures, etching quality test is carried out according to the method for preparing the alkaline etching waste liquid, and the etching rate and the etching factor K are recorded in the table 1.

Example 3

(1) As shown in fig. 3, a heating device is arranged outside the heating evaporation tank, the alkaline waste etching solution with the parameters in table 1 is heated to boiling in the heating evaporation tank, evaporation and concentration are carried out for 5 hours until precipitates are separated out by naked eyes, and a solid-liquid mixture A1 is obtained and is pumped into the acid-base adjustment tank; collecting and introducing gas escaped in the heating process into a combination reaction tank, and under the regulation of the concentration of the externally added carbon dioxide compressed gas, enabling the ratio of the concentration of the ammonia gas in the first combination reaction tank to the concentration of the carbon dioxide to be about 5:1 so as to obtain ammonium carbonate through reaction;

(2) pouring the A1 solid-liquid mixture and hydrochloric acid into an acid-base adjusting tank, mixing and adjusting the pH value to 4, filtering by a filter to obtain solid basic copper chloride, and flushing a combination reaction tank by using filtrate A2 by using filtering pressure to take the ammonium carbonate obtained in the step (1) out of the tank to obtain an A3 mixed solution; then draining the liquid into the sub-liquid preparation tank;

(3) and adding and supplementing required components into the A3 mixed solution according to the component proportion of the recycled sub-solution required by the etching process in the table 1 in a sub-solution preparation tank to prepare the recycled etching sub-solution. The prepared recycled etching sub-solution is automatically detected by an automatic detection feeding control machine according to the pH parameter in the table 1 and is added to an etching production line for etching working procedures, etching quality test is carried out according to the method for preparing the alkaline etching waste solution, and the etching rate and the etching factor K are recorded in the table 1.

Example 4

(1) As shown in fig. 4, a heating evaporation tank provided with a reflux stirring device and a heating device outside is used for heating the alkaline etching waste liquid with the parameters in table 1 to 100 ℃, and evaporation concentration is carried out for 8 hours until precipitates are separated out by naked eyes, so as to obtain a1 solid-liquid mixture, and the solid-liquid mixture is pumped into an acid-base adjustment tank; collecting gas escaped in the heating process and respectively introducing the gas into the first and second combination reaction tanks; under the regulation of the concentration of the compressed gas of the externally added carbon dioxide, the ratio of the concentration of the ammonia gas to the concentration of the carbon dioxide in the first combination reaction tank is about 7.5:1 to obtain ammonium carbonate through reaction, the concentration of the carbon dioxide in the second combination reaction tank is higher than the concentration of the ammonia gas, and the molar concentration ratio of the carbon dioxide to the ammonia gas is kept about 10:1 to obtain ammonium bicarbonate through reaction;

(2) pouring the A1 solid-liquid mixture and the circuit board acidic etching waste liquid into an acid-base adjusting tank to mix and adjust the pH value to 5, filtering by a filter to obtain solid basic copper chloride, and simultaneously flushing a first and a second combined reaction tanks by using a filtrate A2 by using filtering pressure to take the ammonium carbonate and the ammonium bicarbonate obtained in the step (1) out of the tanks to obtain an A3 mixed solution; then draining the liquid into the sub-liquid preparation tank;

(3) and adding and supplementing required components into the A3 mixed solution according to the component proportion of the recycled sub-solution required by the etching process in the table 1 in a sub-solution preparation tank to prepare the recycled etching sub-solution. The prepared recycled etching sub-solution is automatically detected by an automatic detection feeding control machine according to specific gravity parameters in the table 1 and is added to an etching production line for etching working procedures, etching quality test is carried out according to the method for preparing the alkaline etching waste solution, and the etching rate and the etching factor K are recorded in the table 1.

Example 5

(1) As shown in fig. 5, a heating evaporation tank provided with a motor-driven stirring device and a heating device outside is used for heating the alkaline etching waste liquid with the parameters in table 1 to 50 ℃, and after precipitates are separated out after evaporation concentration is carried out for 48 hours, a solid-liquid mixture A1 is obtained and is pumped into an acid-base adjustment tank; collecting the gas escaped in the heating process and respectively introducing the gas into a first combined reaction tank and a second combined reaction tank which are also provided with jet devices for conducting tail gas guiding and collecting treatment;

(2) under the regulation of the concentration of the externally added carbon dioxide compressed gas, the ratio of the concentration of ammonia gas to the concentration of carbon dioxide in the first combination reaction tank is about 5.2:1 to obtain ammonium carbonate through reaction, the concentration of carbon dioxide in the second combination reaction tank is higher than that of ammonia gas, and the molar concentration ratio of carbon dioxide to ammonia gas is kept about 1.01:1 to obtain ammonium bicarbonate through reaction; the tail gas of the chemical combination reaction tank is mixed with water and absorbed through a connected jet device; the collecting cylinder of the jet device is provided with a pH meter for carrying out pH detection on the solution in the collecting cylinder, and the amount of carbon dioxide entering the second combined reaction tank is automatically controlled through the measured numerical value;

(3) mixing the A1 solid-liquid mixture and the circuit board acidic etching waste liquid in an acid-base adjusting tank to adjust the pH value to 5, filtering by a filter to obtain solid basic copper chloride, and flushing a first and a second combined reaction tanks by using filtrate A2 by using filtering pressure to take the ammonium carbonate and the ammonium bicarbonate obtained in the step (1) out of the tanks to obtain an A3 mixed solution; then draining the liquid into the sub-liquid preparation tank;

(4) and adding and supplementing other required components into the A3 mixed solution according to the component proportion of the recycled etching solution required by the etching process in the table 1 in an etching solution preparation tank to prepare the recycled etching solution. The prepared recycled etching sub-solution is automatically detected by an automatic detection feeding control machine according to specific gravity parameters in the table 1 and is added to an etching production line for etching working procedures, etching quality test is carried out according to the method for preparing the alkaline etching waste solution, and the etching rate and the etching factor K are recorded in the table 1.

Example 6

(1) As shown in fig. 6, a heating device is arranged outside the heating evaporation tank, the alkaline waste etching solution with the parameters in table 1 is heated to boiling, evaporation and concentration are carried out for 8 hours until precipitates are separated out by naked eyes, and a solid-liquid mixture A1 is obtained and is pumped into the acid-base adjustment tank; collecting and introducing gas emitted in the heating process into a combination reaction, and enabling the ratio of the concentration of the ammonia gas and the concentration of the carbon dioxide gas in a combination reaction tank to be about 5.2:1 so as to obtain ammonium carbonate through the reaction;

(2) mixing the A1 solid-liquid mixture with hydrochloric acid in an acid-base adjusting tank to adjust the pH value to 4, filtering by a filter to obtain solid basic copper chloride, and flushing a combination reaction tank by using filtrate A2 by using filtering pressure to take the ammonium carbonate obtained in the step (1) out of the tank to obtain an A3 mixed solution; then draining the liquid into the sub-liquid preparation tank;

(3) adding and supplementing required components into the A3 mixed solution according to the component proportion of the recycled sub-solution required by the etching process in the table 1 in a sub-solution preparation tank to prepare the recycled etching sub-solution, automatically detecting and adding the recycled etching sub-solution according to specific gravity parameters in the table 1 by an automatic detection and feeding controller, automatically detecting and adding 25% ammonia water solution according to the pH value for an etching process on an etching production line, testing the etching quality according to the method for preparing the alkaline etching waste liquid, and recording the etching rate and the etching factor K in the table 1.

Example 7

The contents of the components of example 7 and the parameters of the automatic test feed control machine are shown in table 1 below, and the procedure of example 5 is repeated. Wherein the ratio of the concentration of ammonia gas to the concentration of carbon dioxide gas in the first combination reaction tank is about 9:1 to obtain ammonium carbonate by the reaction.

The etching quality test was carried out according to the method described for the preparation of alkaline etching waste liquid, and the etching rate and the etching factor K are shown in Table 1.

Example 8

The contents of the components of example 8 and the parameters of the automatic test feed control machine are shown in table 1 below, and the procedure of example 3 is repeated. Wherein, the alkaline etching waste liquid with the parameters in the table 1 is heated to boiling and evaporated and concentrated for 6 hours.

Example 9

The contents of the components of example 9 and the parameters of the automatic test feed control machine are shown in table 1 below, and the procedure of example 3 is repeated. Wherein, the alkaline etching waste liquid with the parameters in the table 1 is heated to boiling and evaporated and concentrated for 12 hours.

Example 10

The contents of the components of example 10 and the parameters of the automatic test feed control machine are shown in table 1 below, and the procedure of example 5 is repeated. Wherein the alkaline waste etching solution with the parameters in the table 1 is heated to boiling and evaporated and concentrated for 15 hours.

Example 11

The contents of the components of example 11 and the parameters of the automatic test feed control machine are shown in table 1 below, and the procedure of example 1 is repeated. Wherein the alkaline etching waste liquid with the parameters in the table 1 is heated to 70 ℃ and is evaporated and concentrated for 3 hours, so that the carbon dioxide concentration in the chemical combination reaction tank is higher than the ammonia concentration for chemical reaction, and the molar concentration ratio of the carbon dioxide to the ammonia is kept at about 500: 1.

Example 12

The contents of the components of example 12 and the parameters of the automatic test feed control machine are shown in table 1 below, and the procedure of example 3 is repeated. Wherein, the alkaline etching waste liquid with the parameters in the table 1 is heated to boiling and is evaporated and concentrated for 15 hours, the heating evaporation tank and the acid-base adjusting tank are not connected by a pipeline, A1 solid-liquid mixture is manually transferred, and a heating device is arranged near the liquid inlet of the chemical combination reaction tank.

Example 13

The contents of the components of example 13 and the parameters of the automatic test feed control machine are shown in table 1 below, and the procedure of example 3 is repeated. Wherein, the alkaline etching waste liquid with the parameters in the table 1 is heated to boiling and is evaporated and concentrated for 15 hours, and heating devices are arranged near a carbon dioxide inlet, a waste liquid gas inlet and a liquid inlet of the chemical combination reaction tank.

Example 14

The contents of the components of example 14 and the parameters of the automatic test feed control machine are shown in table 1 below, and the procedure of example 5 is repeated. Wherein the alkaline waste etching solution with the parameters in the table 1 is heated to boiling and evaporated and concentrated for 15 hours.

Example 15

The contents of the components of example 15 and the parameters of the automatic test feed control machine are shown in table 1 below, and the procedure of example 5 is repeated. Wherein, the alkaline etching waste liquid with the parameters in the table 1 is heated to boiling and evaporated and concentrated for 50 hours, and the ratio of the ammonia gas concentration to the carbon dioxide gas concentration in the first combination reaction tank is about 8.3:1, so as to obtain ammonium carbonate through reaction.

Example 16

The contents of the components of example 16 and the parameters of the automatic test feed control machine are shown in table 1 below, and the procedure of example 1 is repeated. Wherein, the alkaline etching waste liquid with the parameters in the table 1 is heated to boiling and is evaporated and concentrated for 4.5 hours, an air outlet is arranged on the combination reaction tank besides a carbon dioxide inlet and a waste liquid gas inlet, so that the carbon dioxide quantity concentration of the combination reaction tank is higher than the ammonia gas quantity concentration, the molar weight concentration ratio of the carbon dioxide to the ammonia gas is kept about 100:1, ammonium bicarbonate is obtained by reaction, and the ammonium bicarbonate generated in the combination reaction tank is manually transferred without pipeline connection between the combination reaction tank and the sub-liquid blending tank.

Examples 17 and 18

The contents of the components of examples 17 and 18 and the parameters for the automatic test feed control machine are shown in table 1 below, and the procedure of example 5 is repeated. Wherein, the alkaline etching waste liquid with the parameters in the table 1 is heated to boiling and evaporated and concentrated for 50 hours, and the ratio of the ammonia gas concentration to the carbon dioxide gas concentration in the first combination reaction tank is about 8.3:1, so as to obtain ammonium carbonate through reaction.

Example 19

The contents of the components of example 19 and the parameters of the automatic test feed control machine are shown in table 1 below, and the procedure of example 5 is repeated.

Example 20

The contents of the components of example 20 and the parameters of the automatic test feed control machine are shown in table 1 below, and the procedure of example 3 is repeated. Wherein, the alkaline etching waste liquid with the parameters in the table 1 is heated to boiling and evaporated and concentrated for 6 hours.

TABLE 1

According to the data in table 1, the etching rate of the recyclable etching solution obtained by the invention meets the efficiency of the current industrial scale production, and the defect of quality reduction does not exist.

The above-described embodiments of the present invention are not intended to limit the scope of the present invention, and the embodiments of the present invention are not limited thereto, and various other modifications, substitutions and alterations can be made to the above-described structure of the present invention without departing from the basic technical concept of the present invention as described above, according to the common technical knowledge and conventional means in the field of the present invention.

Claims

1. An ammonia distillation recovery and circulation process for alkaline etching waste liquid of a circuit board is characterized by comprising the following steps:

(1) gas-liquid separation of etching waste liquid: heating the alkaline etching waste liquid with the copper ion concentration of 30-180g/L, pH value of 7-9, and collecting gas generated in the heating process to obtain waste liquid gas; when the etching waste liquid is heated until a precipitate is separated out, a solid-liquid mixture A1 is obtained;

(2) adjusting the pH value: mixing the solid-liquid mixture A1 obtained in the step (1) with hydrochloric acid and/or acidic etching waste liquid, adjusting the pH to 3-6, further increasing the precipitate in the solid-liquid mixture A1, and separating the precipitate in the obtained solid-liquid mixture A1; respectively obtaining solid precipitates and a mixed solution A2 after solid-liquid separation;

(3) and (3) gas treatment: mixing the waste liquid gas collected in the step (1) with carbon dioxide to generate ammonium carbonate and/or ammonium bicarbonate;

(4) mixing the solution: adding ammonium carbonate and/or ammonium bicarbonate into the mixed solution A2 obtained in the second step to obtain a mixed solution A3;

(5) regeneration of etching solution: and supplementing other required components for the etching process into the mixed solution A3 obtained in the step four to obtain the etching solution for recycling.

2. The ammonia distillation recovery and circulation process of the alkaline waste etching solution for circuit boards as claimed in claim 1, which is characterized in that: in the step (4), the solid-liquid mixture A1 obtained in the step (1) is used, and when the pH value is adjusted in the step (2) and then filtration separation is carried out, the ammonium carbonate and/or ammonium bicarbonate obtained in the step (3) is washed and dissolved by the filtered mixed solution A2, so that the mixed solution A3 is obtained.

3. The ammonia distillation recovery and circulation process of the alkaline waste etching solution for circuit boards as claimed in claim 1, which is characterized in that: in the step (3), the gas collected in the step (1) is divided into two parts, so that the mass concentration of the ammonia gas in the first part is greater than that of the carbon dioxide; the mass concentration of the second portion of ammonia gas is made less than the mass concentration of the carbon dioxide species in order to control the ratio of ammonium carbonate and ammonium bicarbonate produced.

4. The ammonia distillation recycling process of alkaline waste etching solution for circuit boards according to claim 1 or claim 3, characterized in that: and (3) a jet device is used, and water is used as jet liquid to absorb tail gas of the synthesis reaction of the waste liquid gas and carbon dioxide to generate ammonium carbonate and/or ammonium bicarbonate.

5. The ammonia distillation recovery and circulation process of the alkaline waste etching solution for circuit boards as claimed in claim 4, which is characterized in that: in the step (3), a jet device is used, and water is used as jet liquid to absorb tail gas of a synthesis reaction of the waste liquid gas and carbon dioxide to generate ammonium carbonate and/or ammonium bicarbonate so as to obtain an aqueous solution; and (3) detecting the pH value of the aqueous solution obtained in the jet device by using a pH meter, and controlling the adding amount of the carbon dioxide gas in the step (3).

6. The ammonia distillation recovery and circulation process of the alkaline waste etching solution for circuit boards as claimed in claim 1, which is characterized in that: and (2) stirring the alkaline etching waste liquid by using a stirring device in the heating process of the step (1) so as to promote gas to escape from a stirring position.

7. The ammonia distillation recovery and circulation process of the alkaline waste etching solution for circuit boards as claimed in claim 4, which is characterized in that: and (2) stirring the alkaline etching waste liquid by using a stirring device in the heating process of the step (1) so as to promote gas to escape from a stirring position.

8. The ammonia distillation recycling process of alkaline waste etching solution for circuit boards of claim 1 or claim 5, which is characterized in that: and (2) during and/or after the heating process in the step (1), injecting air into the alkaline etching waste liquid by using an external pressurized air insertion tube, stirring the mixture in the heating container, and simultaneously promoting the volatilized gas of the mixture to rapidly enter the step (3) for synthesis reaction.

9. The ammonia distillation recovery and circulation process of the alkaline waste etching solution for circuit boards as claimed in claim 1, which is characterized in that: and (3) other required components of the etching process in the step (5) comprise at least one of ammonium chloride, ammonia water, ammonium bicarbonate, water and etching additives.

10. A system for recycling ammonia evaporation from alkaline waste etching solution for circuit boards as claimed in any of claims 1 to 9, comprising:

the acid-base adjusting groove is used for adjusting the pH value of residual liquid after the alkaline etching waste liquid is evaporated;

the at least one chemical combination reaction tank is provided with a carbon dioxide inlet and a waste liquid gas inlet; the carbon dioxide inlet is connected with a carbon dioxide source, the waste liquid gas inlet is connected with the gas outlet of the heating evaporation tank, and the waste liquid gas inlet is used for producing ammonium carbonate and/or ammonium bicarbonate;

the device comprises at least one filter, a liquid-solid separation device and a liquid-solid separation device, wherein the filter is used for separating solid and liquid in a solid-liquid mixture, an inlet of the filter is connected with an acid-base adjusting tank, and a liquid outlet of the filter is connected with a sub-liquid adjusting tank or a chemical combination reaction tank;

11. The system for the ammonia distillation recovery and circulation process of the alkaline waste etching solution for circuit boards according to claim 10, is characterized in that: and a stirring device is arranged in the heating evaporation tank.

12. The system for the ammonia distillation recovery and circulation process of the waste alkaline etching solution of circuit boards of claim 10 or 11, which is characterized in that: the heating evaporation tank is provided with an external pressurized air insertion pipe; the external pressurized air insertion pipe is composed of a pipeline and a pump, wherein the pipeline is communicated with the inside of the heating evaporation groove and the outside.

13. The system for the ammonia distillation recovery and circulation process of the alkaline waste etching solution for circuit boards according to claim 10, is characterized in that: a pump is arranged on a pipeline connecting the heating evaporation tank and the chemical combination reaction tank and/or at the air outlet of the chemical combination reaction tank.

14. The system for the ammonia distillation recovery and circulation process of the alkaline waste etching solution for circuit boards according to claim 10, is characterized in that: the combination reaction tank is provided with an additional air outlet and/or an additional liquid inlet and/or a material outlet.

15. The system for the ammonia distillation recovery and circulation process of the alkaline waste etching solution for circuit boards according to claim 10, is characterized in that: and a heating device is arranged near the carbon dioxide inlet and/or the waste liquid gas inlet and/or the liquid inlet of the combination reaction tank.

16. The system for the ammonia distillation recovery and circulation process of the alkaline waste etching solution for circuit boards according to claim 10, is characterized in that: the chemical combination reaction tank is connected with the jet device;

the jet device is provided with a gas-liquid mixing cavity and a collecting cylinder, and water is stored in the collecting cylinder and is used for dissolving tail gas of the chemical combination reaction tank;

17. The system for the ammonia distillation recovery and circulation process of the alkaline waste etching solution for circuit boards according to claim 16, is characterized in that: and a pH meter is arranged in a collecting cylinder of the jet device and is used for detecting the pH value of liquid in the collecting cylinder.