1. A method for treating stripping and hanging waste liquid in a PCB factory is characterized by comprising the following steps:

s1: pretreatment of stripping waste liquid:

filtering impurities from the stripped waste liquid, acidifying, adding an alkaline raw material for neutralization reaction, adjusting the hydrogen ion concentration of the solution to 0.2-0.5mol/L, and heating the solution for reaction;

s2: synthesizing copper sulfate pentahydrate:

s21, heating and concentrating the acidized fluid treated in the step S1 until the density of the acidized fluid reaches 1.45-1.5g/cm³Then cooling and crystallizing the acidified liquid;

s22, centrifugally separating the cooled concentrated solution to obtain an industrial or feed-grade copper sulfate pentahydrate product and a mother solution;

s3: and (3) full recovery of sulfate radicals:

mixing ammonia water and the mother liquor obtained in S22 for reaction, primarily heating, controlling the pH of the solution to be 4.4-5.0, continuously heating, and filtering and separating to obtain basic copper sulfate and clear filtrate after the reaction is completed;

s4: tail water evaporation:

and (4) adsorbing copper ions in the solution by using the clear filtrate obtained in the step (S3), and evaporating and concentrating to finally obtain an industrial-grade ammonium chloride product and distilled water.

2. The method for treating the stripping waste liquid of the PCB factory as claimed in claim 1, wherein the alkaline raw material in S1 comprises: one or more of basic copper chloride, copper hydroxide, copper sulfate or copper oxide.

3. The method for treating the stripping waste liquid of the PCB factory as claimed in claim 1, wherein the conditions for the heating reaction of the solution in S1 are as follows: heating to above 80 ℃ and reacting for 1-2 h.

4. The method for treating the stripping waste liquid in the PCB factory as claimed in claim 1, wherein the acidified liquid in S21 is cooled to below 40 ℃.

5. The PCB factory stripping and hanging waste liquid treatment method as claimed in claim 1, wherein the mother liquid obtained in S22 is evaporated and concentrated, and the density of the discharged liquid is controlled to be 1.45-1.5g/cm³And then the discharged liquid is sent to a cooling crystallization process in S21, and the processes from S21 to S22 are repeated, so that a copper sulfate pentahydrate product and a secondary mother liquid can be obtained.

6. The PCB factory stripping waste liquid treatment method as claimed in claim 1, wherein the mother liquor obtained in S22 is evaporated and concentrated by an MVR evaporation system.

7. The PCB factory stripping and hanging waste liquid treatment method as claimed in claim 1, wherein the preliminary heating in S3 is to 50 ℃ -60 ℃; continuously heating to 70-80 ℃.

8. The method for treating the stripping waste liquid in the PCB factory as claimed in claim 1, wherein the basic copper sulfate obtained in S3 is fed into S1 as an alkaline raw material to perform a neutralization reaction with the stripping waste liquid.

9. The PCB factory stripping waste liquid treatment method according to claim 1, wherein copper ions in the clear filtrate are adsorbed by resin in S4.

10. The PCB factory stripping waste liquid treatment method according to claim 1, wherein the clear filtrate after adsorption in S4 is evaporated and concentrated by a triple effect evaporation system.

Background

At present, most PCB factories discharge stripping and hanging waste liquid to a waste water station for comprehensive treatment with other waste water, so that not only resources are wasted, but also great pollution is caused to the environment. Therefore, the stripping waste liquid is discharged after being treated. The current treatment methods mainly comprise the following methods:

1. iron powder replacement method: the iron powder replacement method is mainly characterized in that reduced iron powder (generally, iron powder is low in purity and basically contains sulfur) is added to replace copper with sponge copper, a large amount of hydrogen volatilizes in the replacement process, the hydrogen contains a small amount of hydrogen sulfide gas to volatilize, certain pollution is caused to air, in addition, the acid content of stripping liquid is high, and the loss of the iron powder is large; 2. copper extraction by an electrolytic method: at present, most manufacturers in China adopt an electrolytic method to extract copper in microetching liquid, wherein the copper extraction by the electrolytic method mainly comprises the steps of pumping the copper-containing microetching liquid into an electrolytic bath, electrifying and electrolyzing to obtain electrolytic copper sheets finally; the method is simple to operate, but has high power consumption and low economic benefit; the waste liquid with low copper content is difficult to electrolyze, copper is difficult to electrolyze completely, and the waste liquid after electrolysis is directly discharged or comprehensively treated with other waste water, so that the problems of secondary environmental pollution and low resource utilization rate of the waste liquid are caused; 3. alkali neutralization: some manufacturers directly add alkali to neutralize the deplating waste liquid by a precipitation filter pressing method for convenient treatment, and then sell the deplating waste liquid to a copper smelting plant for smelting and extracting copper; the method not only needs to consume a large amount of alkali, but also improves the wastewater treatment cost; meanwhile, copper metal in the waste liquid cannot be effectively utilized, a large amount of sulfate in the waste acid is directly discharged to a tail water treatment system, heavy burden is caused to a water discharge system, and resource waste is caused.

Disclosure of Invention

The invention aims to provide a method for treating stripping and hanging waste liquid of a PCB factory, which can realize the recovery of valuable metal copper and the recovery of sulfate radicals at the same time, and finally realize zero emission of the waste liquid in a distilled water mode, thereby achieving the purpose of resource utilization and meeting the requirement of environmental protection.

The embodiment of the invention is realized by the following technical scheme:

a method for treating stripping and hanging waste liquid of a PCB factory comprises the following steps:

s1: pretreatment of stripping waste liquid:

filtering impurities from the stripping waste liquid, acidifying, adding an alkaline raw material for neutralizing, adjusting the concentration of hydrogen ions in the solution to be 0.2-0.5mol/L, and heating the solution for reaction;

s2: synthesizing copper sulfate pentahydrate:

s21, heating and concentrating the acidized fluid treated in the step S1 until the density of the acidized fluid reaches 1.45-1.5g/cm³Then cooling and crystallizing the acidified liquid;

s22, centrifugally separating the cooled concentrated solution to obtain an industrial or feed-grade copper sulfate pentahydrate product and a mother solution;

s3: and (3) full recovery of sulfate radicals:

mixing ammonia water and the mother liquor obtained in S22 for reaction, primarily heating, controlling the pH of the solution to be 4.4-5.0, continuously heating, and filtering and separating to obtain basic copper sulfate and clear filtrate after the reaction is completed;

s4: tail water evaporation:

and (4) adsorbing copper ions in the solution by using the clear filtrate obtained in the step (S3), and evaporating and concentrating to finally obtain an industrial-grade ammonium chloride product and distilled water.

The technical scheme of the embodiment of the invention at least has the following advantages and beneficial effects:

1. the method can completely recover valuable metal copper and copper sulfate ions in the stripping and hanging waste liquid, has high resource utilization degree, and can recover and utilize metal copper and sulfate radicals in the stripping and hanging waste liquid in a high value-added copper sulfate form, so that the obtained blue copperas product has high quality and can be sold directly; the recovery rate of copper ions and sulfate radicals can reach 100 percent, and the benefit maximization is achieved.

2. The invention adopts an MVR evaporation system to evaporate mother liquor and a triple-effect evaporation system to evaporate clear filtrate produced by basic copper sulfate finally, and finally obtains distilled water.

3. The stripping waste liquid treatment method is also suitable for copper-containing waste liquids of other sulfuric acid hydrogen peroxide systems, such as microetching liquid, browning liquid and the like, and provides reliable guarantee for resource utilization of the copper-containing waste liquid and treatment of the waste liquid.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present invention and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained according to the drawings without inventive efforts.

FIG. 1 is a schematic view of the process flow of the stripping waste liquid treatment method of the PCB factory.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. The examples, in which specific conditions are not specified, were conducted under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products available commercially.

A method for treating stripping and hanging waste liquid of a PCB factory comprises the following steps:

s1: pretreatment of stripping waste liquid:

filtering impurities from the stripping waste liquid, acidifying, adding an alkaline raw material for neutralizing, adjusting the concentration of hydrogen ions in the solution to be 0.2-0.5mol/L, and heating the solution for reaction;

in the pretreatment stage of the stripping and hanging waste liquid, the acidity in a solution system is reduced by adjusting the concentration of hydrogen ions in the solution, so that the generation of a copper sulfate product and the quality of the copper sulfate product are facilitated; and the solution is heated to react, thereby promoting the smooth proceeding of the reaction and leading the reaction to be more complete.

S2: synthesizing copper sulfate pentahydrate:

s21, heating and concentrating the acidized fluid treated in the step S1 until the density of the acidized fluid reaches 1.45-1.5g/cm³Then cooling and crystallizing the acidified liquid; in the step, the density of the acidification liquid is controlled to judge the concentration end point so as to better perform the reaction system and provide reliable guarantee for producing copper sulfate;

s22, centrifugally separating the cooled concentrated solution to obtain an industrial or feed-grade copper sulfate pentahydrate product and a mother solution; it is noted that the copper sulfate pentahydrate product obtained at this time can be directly sold after being analyzed, detected and packaged, and the high resource utilization of the stripping waste liquid is realized;

s3: and (3) full recovery of sulfate radicals:

mixing ammonia water and the mother liquor obtained in S22 for reaction, primarily heating, controlling the pH of the solution to be 4.4-5.0, continuously heating, and filtering and separating to obtain basic copper sulfate and clear filtrate after the reaction is completed; at the moment, sulfate radicals in the mother liquor are completely converted into basic copper sulfate, and the basic copper sulfate is returned to S1 again to be used as a basic raw material to regulate the acidity of the solution;

in the step, the solution system is heated for several times, so that the temperature rise process of the solution system is quicker and more stable, and the quality of a product generated after reaction is ensured.

S4: tail water evaporation:

and (4) adsorbing copper ions in the solution by using the clear filtrate obtained in the step (S3), and evaporating and concentrating to finally obtain an industrial-grade ammonium chloride product and distilled water. The obtained industrial-grade ammonium chloride product can be sold as a product, and distilled water can directly enter a tail water treatment system or be used for a circulating cooling water system and the like, so that the consumption of tap water is reduced, the waste of water resources is avoided,

therefore, the sulfate radicals in the stripping waste liquid can be utilized to the maximum extent, the sulfate radicals in the mother liquor which cannot be effectively utilized can be returned to a copper sulfate production system again after basic copper sulfate is produced, and the method can be repeatedly recycled; and the metal copper and sulfate radicals in the stripping and hanging waste liquid are all recovered in a form of copper sulfate with high added value and are recycled, so that the maximum benefit is achieved; therefore, the invention realizes the recovery of valuable metal copper and the recovery of sulfate radical, realizes zero emission of resources and achieves the aim of resource utilization. And the tail water obtained by final treatment is evaporated to obtain distilled water through evaporation equipment, and the distilled water is discharged to a tail water treatment system in a distilled water form, so that the pressure of the tail water treatment system is minimized, and the tail water treatment system meets the requirement of environmental protection.

Therefore, one part of the stripping waste liquid is finally recycled in the form of copper sulfate with high added value and is recycled, and the other part of the stripping waste liquid realizes zero emission in the form of distilled water, thereby achieving higher utilization value and environmental protection requirements.

Further, the alkaline raw material in S1 includes: one or more of basic copper chloride, copper hydroxide, copper sulfate and copper oxide are generated by self. The invention uses the basic copper chloride/copper hydroxide/copper oxide produced by the factory as the alkaline raw material to neutralize the stripping waste liquid, does not need to purchase alkaline raw materials such as sodium hydroxide and the like, greatly reduces the cost of purchased raw materials, and saves the cost for treating the stripping waste liquid.

Further, the conditions for the heating reaction of the solution in S1 are: heating to above 80 ℃ and reacting for 1-2 h.

Further, the acidified liquid in S21 was cooled to below 40 ℃. Because the solution temperature of the copper sulfate is reduced along with the temperature reduction, the more complete precipitation of the copper sulfate crystals can be ensured below 40 ℃, and more copper sulfate products can be obtained.

Further, evaporating and concentrating the mother liquor obtained in S22 by using an MVR evaporation system, and controlling the density of the discharged liquid to be 1.45-1.5g/cm³And then the discharged liquid is sent to a cooling crystallization process in S21, and the processes from S21 to S22 are repeated, so that a copper sulfate pentahydrate product and a secondary mother liquid can be obtained. The mother liquor is evaporated and concentrated by an MVR evaporation system, and the final discharged water enters a tail water system in the form of distilled water, so that the environment-friendly requirement is met.

Further, primarily heating to 50-60 ℃ in S3; continuously heating to 70-80 ℃.

Further, the basic copper sulfate obtained in the S3 is sent into the S1 to be used as an alkaline raw material to perform neutralization reaction with the stripping waste liquid, so that the resource utilization degree is high, and the obtained copper sulfate pentahydrate product has high quality and can be directly sold for the outside; the recovery rate of copper ions and sulfate radicals can reach 100 percent at most. The basic copper sulfate is produced by the treatment process and is returned to the system for producing the copper sulfate. The method can convert all sulfate radicals in the waste liquid into high-value copper sulfate products, residual sulfate radicals can not enter a tail water treatment system, and the method can be repeatedly recycled.

Further, in S4, copper ions in the clear filtrate are adsorbed by the resin.

Further, the clear filtrate adsorbed in the S4 is evaporated and concentrated by a triple effect evaporation system.

Example 1

A method for treating stripping and hanging waste liquid of a PCB factory comprises the following steps:

s1: pretreatment of waste stripping and hanging liquid

Removing impurities from the stripping waste liquid by a filtering system, then feeding the stripping waste liquid into an acidification kettle, and simultaneously starting stirring; putting the raw material of the self-produced basic copper chloride into a kettle through a feeding port of an acidification kettle, adjusting the hydrogen ion concentration of the solution to be 0.2mol/L, starting a heating system to heat the solution concentration to 80 ℃ and reacting for 2 hours, and pumping the acidification liquid in the acidification kettle into a crystallization kettle after the reaction is finished;

s2: synthesis of blue vitriod

S21, pumping the acidizing fluid into a crystallization kettle, starting a steam heating system and a negative pressure system, concentrating the acidizing fluid until the density of the acidizing fluid reaches 1.45g/cm³Closing the steam heating system and the negative pressure system, naturally cooling to 50 ℃, then opening the cooling circulating water system, and controlling the final temperature of the concentrated solution to be 40 ℃;

s22, after the temperature is reduced to 40 ℃, discharging the concentrated solution in the crystallization kettle, separating by a centrifugal machine, and cleaning by tap water to obtain an industrial-grade or feed-grade copper sulfate pentahydrate product and a mother solution;

s23, allowing the mother liquor to enter an MVR evaporation system, and further performingEvaporating and concentrating, and controlling the density of discharged liquid at 1.45g/cm³Feeding the discharged liquid into a crystallization kettle in S22 for cooling crystallization, cooling, discharging and centrifuging, and repeating the processes from S21 to S22 to finally obtain a copper sulfate pentahydrate product and a secondary mother liquid;

s3: sulfate radical full recovery system

Heating the secondary mother liquor and ammonia water to 50 ℃ through a preheating tank, pumping into a basic copper sulfate synthesis kettle, controlling the pH value of the solution to be 4.4, introducing steam to raise the temperature to 70 ℃, starting stirring, and filtering to obtain green sand-shaped crystals, namely basic copper sulfate and blue transparent clear filtrate after complete reaction;

s4: tail water evaporation system

And adsorbing copper ions in the solution by the clarified filtrate through resin, and then, evaporating and concentrating the clarified filtrate in a triple-effect evaporation system to finally obtain an industrial-grade ammonium chloride product and distilled water.

Example 2

A method for treating stripping and hanging waste liquid of a PCB factory comprises the following steps:

s1: pretreatment of waste stripping and hanging liquid

Removing impurities from the stripping waste liquid by a filtering system, then feeding the stripping waste liquid into an acidification kettle, and simultaneously starting stirring; putting raw materials of copper chloride or copper hydroxide or copper oxide which are produced by oneself into a kettle through a feeding port of an acidification kettle, adjusting the hydrogen ion concentration of the solution to be 0.5mol/L, starting a heating system to heat the solution concentration to 90 ℃ and reacting for 1h, and pumping the acidification liquid in the acidification kettle into a crystallization kettle after the reaction is finished;

s2: synthesis of blue vitriod

S21, pumping the acidizing fluid into a crystallization kettle, starting a steam heating system and a negative pressure system, concentrating the acidizing fluid until the density of the acidizing fluid reaches 1.5g/cm³Closing the steam heating system and the negative pressure system, naturally cooling to 50 ℃, then opening the cooling circulating water system, and controlling the final temperature of the concentrated solution to be 30 ℃;

s22, after the temperature is reduced to 30 ℃, discharging the concentrated solution in the crystallization kettle, separating by a centrifugal machine, and cleaning by tap water to obtain an industrial-grade or feed-grade copper sulfate pentahydrate product and a mother solution;

s23, allowing the mother liquor to enter an MVR evaporation system, further evaporating and concentrating, and controlling the density of the discharged liquid to be 1.5g/cm³Feeding the discharged liquid into a crystallization kettle in S22 for cooling crystallization, cooling, discharging and centrifuging, and repeating the processes from S21 to S22 to finally obtain a copper sulfate pentahydrate product and a secondary mother liquid;

s3: sulfate radical full recovery system

Heating the secondary mother liquor and ammonia water to 60 ℃ through a preheating tank, pumping into a basic copper sulfate synthesis kettle, controlling the pH value of the solution to be 5.0, introducing steam to raise the temperature to 80 ℃, starting stirring, and filtering to obtain green sand-shaped crystals, namely basic copper sulfate and blue transparent clear filtrate after complete reaction;

s4: tail water evaporation system

And adsorbing copper ions in the solution by the clarified filtrate through resin, and then, evaporating and concentrating the clarified filtrate in a triple-effect evaporation system to finally obtain an industrial-grade ammonium chloride product and distilled water.

Example 3

A method for treating stripping and hanging waste liquid of a PCB factory comprises the following steps:

s1: pretreatment of waste stripping and hanging liquid

Removing impurities from the stripping waste liquid by a filtering system, then feeding the stripping waste liquid into an acidification kettle, and simultaneously starting stirring; putting raw materials of copper chloride or copper hydroxide or copper oxide which are produced by oneself into a kettle through a feeding port of an acidification kettle, adjusting the hydrogen ion concentration of the solution to be 0.4mol/L, starting a heating system to heat the solution concentration to 100 ℃ and reacting for 1.5h, and pumping the acidification liquid in the acidification kettle into a crystallization kettle after the reaction is finished;

s2: synthesis of blue vitriod

S21, pumping the acidizing fluid into a crystallization kettle, starting a steam heating system and a negative pressure system to concentrate the acidizing fluid until the density of the acidizing fluid reaches 1.48g/cm³Closing the steam heating system and the negative pressure system, naturally cooling to 50 ℃, then opening the cooling circulating water system, and controlling the final temperature of the concentrated solution to be 35 ℃;

s22, after the temperature is reduced to 35 ℃, discharging the concentrated solution in the crystallization kettle, separating by a centrifugal machine, and cleaning by tap water to obtain an industrial-grade or feed-grade copper sulfate pentahydrate product and a mother solution;

s23, allowing the mother liquor to enter an MVR evaporation system, further evaporating and concentrating, and controlling the density of the discharged liquid to be 1.48g/cm³Feeding the discharged liquid into a crystallization kettle in S22 for cooling crystallization, cooling, discharging and centrifuging, and repeating the processes from S21 to S22 to finally obtain a copper sulfate pentahydrate product and a secondary mother liquid;

s3: sulfate radical full recovery system

Heating the secondary mother liquor and ammonia water to 55 ℃ through a preheating tank, pumping into a basic copper sulfate synthesis kettle, controlling the pH value of the solution to be 4.7, introducing steam to raise the temperature to 75 ℃, starting stirring, and filtering to obtain green sand-shaped crystals, namely basic copper sulfate and blue transparent clear filtrate after complete reaction;

s4: tail water evaporation system

And adsorbing copper ions in the solution by the clarified filtrate through resin, and then, evaporating and concentrating the clarified filtrate in a triple-effect evaporation system to finally obtain an industrial-grade ammonium chloride product and distilled water.

Examples of the experiments

1. The results of the analysis and examination of the physical and chemical indexes of the waste stripping solution and the distilled water discharged after the treatment in example 3 are shown in Table 1,

TABLE 1 physicochemical indices of the stripping waste liquid and the treated distilled water

As can be seen from the data in Table 1: the treatment method can completely recover valuable metal copper and copper sulfate ions, has high resource utilization degree, and can obtain copper sulfate pentahydrate products with higher quality which can be sold outside directly; the recovery rate of copper ions and sulfate radicals can reach 100%.

2. The results of the analysis and examination of the physical and chemical indexes of the distilled water evaporated by the MVR evaporation system in the step S2 and the distilled water evaporated by the triple effect evaporation system in the step S4 in example 3 are shown in Table 2,

TABLE 2 physicochemical indices of distilled water obtained by MVR evaporation and distilled water obtained by triple effect evaporation

Physical and chemical indexes	MVR evaporated distilled water	Triple effect evaporation of distilled water
			Copper ion	Not detected out	Not detected out
Ammonia nitrogen	1.33	3.51
			Sulfate radical	Not detected out	Not detected out
PH	3.53	4.50

As can be seen from the data in Table 2: according to the treatment method, the MVR evaporation system is used for evaporating the mother liquor and the triple effect evaporation system is used for evaporating the filtrate, and finally the discharged water enters the tail water system in the form of distilled water, so that zero discharge of wastewater treatment is realized, and higher utilization value and environmental protection requirements are met.

The above is only a preferred embodiment of the present invention, and is not intended to limit the present invention, and various modifications and changes will occur to those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.