TWI572565B - Treatment of copper - containing waste liquid - Google Patents

Description

Method for treating copper ion waste liquid

The invention relates to a method for treating a copper ion-containing waste liquid, in particular to a method for treating a copper ion-containing waste liquid using an iron-aluminum composite metal and a seed crystal.

Today's industry is developing rapidly, and the demand for industrial water is increasing year by year. However, Taiwan's restrictions on topography and climate have led to insufficient water resources and the problem of insufficient industrial water. Therefore, if industrial waste liquid can be properly treated and meets the standards for recycling, it will effectively solve the problem of insufficient industrial water. In addition, the untreated or improperly treated industrial waste liquid will also pollute the land and water resources after being discharged. Therefore, the waste liquid treatment method is used to effectively reduce the pollutants in the industrial waste liquid to avoid the impact of industrial waste liquid discharge on the environment. The current important topic.

In the manufacturing process of printed circuit boards, a high concentration of copper ion-containing waste liquid is generated. One of the current recycling methods: electrolysis, which uses a high concentration of copper ion-containing waste liquid as an electrolyte for electrolysis to cause oxidation of the anode. Water is electrolyzed into hydrogen, and the main reaction of the cathode is copper precipitation, so metal copper can be directly collected at the cathode. However, during the above reaction, a large amount of hydrogen ions are accumulated in the copper ion-containing waste liquid. In the middle, the pH of the copper ion-containing waste liquid will continue to decrease as the reaction progresses, resulting in the produced outflow waste liquid being strongly acidic and not meeting the discharge water regulations and being unable to discharge directly.

In addition, the copper ion-containing waste liquid often contains a chelating agent component, and since the chelating agent is chelated with the copper ion in the copper ion-containing waste liquid, the copper ion is not easily separated from the copper ion-containing waste liquid, so the conventional It will be treated by ferrous sulfate method, calcium salt treatment method, sodium borohydride reduction method and various redox methods, and the above method will increase the processing cost due to the need to add additional chemicals and generate a large amount of sludge. .

In view of the insufficiency of the existing treatment methods for copper ion-containing waste liquids, it is an urgent task to propose a novel and more sophisticated treatment method for copper ion-containing waste liquids.

Accordingly, it is an object of the present invention to provide a method for treating a copper ion-containing waste liquid which can solve the above-mentioned drawbacks of the prior art and further achieve a good treatment effect.

Therefore, the method for treating a copper ion-containing waste liquid of the present invention comprises the steps of: contacting a copper ion-containing waste liquid with an iron-aluminum composite metal and a seed crystal; wherein the iron-aluminum composite metal reduces the copper ion to copper element, And the copper element The substance grows substantially on the seed crystal into a seed crystal containing copper metal on the surface.

The utility model has the advantages that: by using the iron-aluminum composite metal and the seed crystal, the outflow waste liquid produced by the method for treating the copper ion-containing waste liquid meets the discharge water regulation standard, and can be directly discharged without further treatment. Moreover, the treatment method of the copper ion-containing waste liquid does not produce sludge. Further, the copper ion-containing waste liquid treatment method has a high copper ion unit treatment amount for the copper ion-containing waste liquid, and can long-termly remove copper ions in the copper ion-containing waste liquid, and the surface contains copper metal. The seed crystals are easily separated to recover copper metal while increasing the recovery of copper metal.

Hereinafter, the contents of the present invention will be described in detail. In the method for treating a copper ion-containing waste liquid, the source, composition, properties, and content range of copper ions of the copper ion-containing waste liquid are not particularly limited. The iron-aluminum composite metal can achieve good treatment effects for various pH-containing copper ion waste liquids. Further consideration is made to make the iron-aluminum composite metal have a longer use time and to achieve a better treatment effect on the copper ion-containing waste liquid. Preferably, the copper ion-containing waste liquid has a pH in the range of 4 to 10.

Preferably, the iron-aluminum composite metal has an inner layer formed of zero-valent aluminum, and an outer layer covering the outer layer and formed of zero-valent iron, and the total amount of the iron-aluminum composite metal is 100% by weight. The content of zero-valent aluminum ranges from 75 to 95% by weight, and the content of the zero-valent iron ranges from 5 to 25 wt%. When the content of the zero-valent aluminum and the zero-valent iron is in the above range, the iron-aluminum composite metal has more zero-valent iron to react, and the zero-valent iron does not over-coat the inner layer of zero-valent aluminum to cause the reaction. Unable to proceed. The zero-valent iron (Fe ⁰ ) in the iron-aluminum composite metal reduces copper ions (Cu ²⁺ ) in the copper ion-containing waste liquid to zero-valent copper (Cu ⁰ ), and the zero-valent iron oxidizes to ferrous ions. (Fe ²⁺ ), at this time, the electrons supplied via zero-valent aluminum (Al ⁰ ) will reduce the ferrous ions to zero-valent iron. Through the above mechanism, the iron-aluminum composite metal can continuously reduce the copper ions into Copper element. And because the activity of the redox reaction between zero-valent iron (Fe ⁰ ) and copper ions (Cu ²⁺ ) is greater than the stability of the chelate compound combined with the copper ion, the chelating agent in the copper ion-containing waste liquid It does not affect the treatment effect of the treatment method containing the copper ion waste liquid.

The seed crystal enables the copper element to be substantially on the seed crystal and promotes the copper element to grow into copper metal on the surface of the seed crystal. Therefore, if the copper metal obtained is to be recovered from the copper ion-containing waste liquid, It is only necessary to physically separate the seed crystal containing the copper metal on the surface. Preferably, the seed crystal is selected from at least one of quartz sand and garnet sand. Preferably, the seed crystal has an average particle size ranging from 0.85 mm to 2 mm.

Further considering that the copper ion-containing waste liquid treatment method can more effectively remove the copper ions in the copper ion-containing waste liquid, and further contribute to the growth of the seed crystal to a surface containing copper metal seed crystals. Preferably, the weight ratio of the iron-aluminum composite metal to the seed crystal ranges from 1:1 to 5:1.

Preferably, the method for treating a copper ion-containing waste liquid further comprises the step of separating a seed crystal containing copper metal on the surface from the copper ion-containing waste liquid.

Preferably, the method for treating the copper ion-containing waste liquid further comprises the steps of: detaching the copper metal from the seed crystal, and recovering the copper metal. Here, physical separation may be used to separate the copper metal from the seed crystal, and the physical separation is, for example, but not limited to, sieving.

In an embodiment of the method for treating a copper ion-containing waste liquid, the iron-aluminum composite metal and the seed crystal are mixed and filled in a reactor, and then the copper ion-containing waste liquid is introduced into the reactor. The copper ion-containing waste liquid is brought into contact with the iron-aluminum composite metal and the seed crystal. Preferably, the copper ion-containing waste liquid is introduced into the reactor at a flow rate ranging from 10 to 200 ml/min. Preferably, the copper ion-containing waste liquid has a hydraulic retention time (HRT) in the reactor ranging from 10 to 30 minutes.

Preferably, the method for treating a copper ion-containing waste liquid further comprises the steps of: separating a seed crystal containing copper metal on the surface from the reactor, separating the copper metal from the seed crystal, and recovering the copper. metal.

Other features and effects of the present invention will be apparent from the embodiments of the drawings, in which: [Fig. 1] is a photograph of "the seed crystal containing copper metal on the surface" obtained in Example 1 of the method for treating a copper ion-containing waste liquid of the present invention; [Fig. 2] is a treatment method of the copper ion-containing waste liquid of the present invention. a photograph of the "product" obtained in Comparative Example 1; [Fig. 3] is a graph of the first embodiment, illustrating the relationship between the pH value of the discharged waste liquid and time; [Fig. 4] is the same as that of the first embodiment. a graph illustrating the ratio of the ratio of the copper ion concentration of the discharged waste liquid to the copper ion concentration of the copper ion-containing waste liquid and time; and FIG. 5 is a graph of the comparative example 1, illustrating the flow waste liquid The ratio of the copper ion concentration to the copper ion concentration of the copper ion-containing waste liquid as a function of time.

The present invention will be further illustrated by the following examples, but it should be understood that this embodiment is intended to be illustrative only and not to be construed as limiting.

[Preparation example] iron-aluminum composite metal

Add 30 ml of hydrochloric acid (purity: 32%) to 100 ml of deionized water and mix well, then add 10 g of aluminum shavings and continue stirring until the pickling reaction is completed, then add 20 ml of ferric chloride solution (manufacturer: Youhe, purity) : 38%) to carry out the reaction, after the reaction is terminated, an iron-aluminum composite metal is obtained, and the iron-aluminum composite metal has a zero price An inner layer formed of aluminum, and an outer layer coated with the outer layer and formed of zero-valent iron, and in the iron-aluminum composite metal, the weight percentage of zero-valent iron is 15±10% by weight, and the weight percentage of zero-valent aluminum is 85 ±10wt%. The acid remaining on the surface of the iron-aluminum composite metal is washed with a large amount of deionized water and used.

[Example 1] Treatment method of copper ion-containing waste liquid

The mixture was prepared by mixing 450 g of the iron-aluminum composite metal of the preparation example and 450 g of quartz sand (average particle diameter: 0.85 to 2 mm) and filling a column (material: PVC, column length: 100 cm, inner diameter: 5 cm). At 25 ° C, a copper ion-containing waste liquid [for self-configured copper ion aqueous solution, copper ion (Cu ²⁺ ) concentration of 100 mg / liter (referred to as C ₀ )], at a flow rate of 11 ml / min, The column is introduced into the column by the inflow and the upper outflow of the column, and the hydraulic retention time of the copper ion-containing waste liquid in the column is 31 minutes. The concentration and pH of copper ions in the outflow effluent from the column are measured at fixed times per day. The daily measurement was continued until the saturation end point was reached on the 94th day [the saturation end point is defined as the copper ion concentration of the outflow waste liquid is 95% of the copper ion concentration of the copper ion-containing waste liquid]. On the 99th day, the copper ion-containing waste liquid was stopped from flowing into the column, and a "crystal seed having a surface containing copper metal" (shown in Fig. 1) formed in the column was separated. After "the seed crystal containing copper metal on the surface", the copper metal is detached from the seed crystal by sieving.

In Example 1, the daily treated water volume was 15.84 liters (= 11 ml/min × 1440 min / day × 10 ^-3 liter / ml); the treatment time of the copper ion-containing waste liquid was 2376 hours, and the total treatment The amount of waste liquid was 1568.16 liters (=15.84 liters/day x 99 days).

[Comparative Example 1] Treatment method of copper ion-containing waste liquid

The treatment method of the copper ion-containing waste liquid of Comparative Example 1 was carried out in the same manner as in Example 1, except that only 450 g of the iron-aluminum composite metal was used without using quartz sand, and the copper ion concentration of the copper ion-containing waste liquid was used. (C ₀ ) is 300 mg / liter. The saturation end point was reached on the 23rd day, and the copper ion-containing waste liquid was stopped from entering the column on the 30th day, and the product produced in the column was as shown in FIG.

In Comparative Example 1, the daily treated water amount was 15.84 liters; the treatment time of the copper ion-containing waste liquid was 720 hours, and the total amount of waste liquid treated was 475.2 liters (=15.84 liters/day x 30 days).

[evaluation project]

1. pH change of the outflow waste liquid

The pH value of the outflow waste liquid in Example 1 was plotted against time (unit: day). The result is shown in Figure 3.

2. Processing long-term

The ratio of the copper ion concentration (denoted as C _n ) of the outflow waste liquid on day _{n to} the copper ion concentration (denoted as C ₀ ) of the copper ion-containing waste liquid (C _n /C ₀ ) and time (unit: day) The results of Example 1 are shown in Figure 4, and the results of Comparative Example 1 are shown in Figure 5. Wherein, the ratio of the copper ion concentration of the outflow waste liquid on the nth day to the copper ion concentration of the copper ion-containing waste liquid (C _n /C ₀ ) is 0, indicating that copper has not appeared in the outflow waste liquid until the nth day Ion (represents the removal rate of copper ions in the copper ion-containing waste liquid up to 100% by day n); the copper ion concentration of the outflow waste liquid on the nth day is 95 of the copper ion concentration of the copper ion-containing waste liquid When %, it means the saturation end point on the nth day.

3. Copper ion unit throughput

First, according to Mathematical Formula 1, the total amount of copper ions removed by the treatment method of the copper ion-containing waste liquid is calculated.

[Math 1]: Total amount of copper ions removed (g) = Σ [Daily treated water amount × (C ₀ - C _n ) × (day n - n-1 day)] × 10 ^-3

Wherein n represents the number of days, C _n is the copper ion concentration of the outflow waste liquid on the nth day, and C ₀ is the copper ion concentration of the copper ion-containing waste liquid.

Then, according to Mathematical Formula 2, the copper ion unit treatment amount per kg of the iron-aluminum composite metal in the treatment method of the copper ion-containing waste liquid is calculated.

[Math 2]: Copper ion unit treatment amount per kg of iron-aluminum composite metal = total amount of copper ions removed (g) ÷ iron-aluminum composite metal used (kg)

4. Copper metal recovery rate

One gram of "the seed crystal containing copper metal on the surface" of Example 1 and one gram of the product of Comparative Example 1 were respectively taken, and according to "the method for detecting heavy metals in soil - aqua regia digestion method (method numbered NIEA S321. The 64B) method analyzes the copper metal content (mg). Further, the copper metal content of Example 1 was divided by 1 gram of "the seed crystal containing copper metal on the surface" to obtain the copper metal recovery rate of Example 1. Further, the copper metal content of Comparative Example 1 was divided by 1 gram of the product to obtain the copper metal recovery ratio of Comparative Example 1.

The results of the treatment of long-acting, copper ion unit treatment amount and copper metal recovery rate are summarized in Table 1.

As shown in FIG. 3, the pH of the outflow waste liquid produced by the method for treating copper ion waste liquid of Example 1 is maintained at 5 to 7, which is weakly acidic to neutral, indicating that the outflow waste liquid meets the discharge water regulation standard. It can be discharged directly without any treatment. Further, from the discharge waste liquid of Example 1 and the column after the completion of the treatment, it can be seen that the treatment method of the copper ion-containing waste liquid of Example 1 does not produce sludge.

As shown in Table 1, from Example 1 until the 56th day, the ratio of the copper ion concentration of the outflow waste liquid to the copper ion concentration of the copper ion-containing waste liquid (C _n /C ₀ ) is still 0, which represents an example. The removal rate of copper ions in the copper ion-containing waste liquid is 100% sustainable until day 56. And in Example 1, the saturation end point was not reached until the 94th day.

In Comparative Example 1, the ratio (C _n /C ₀ ) of the copper ion concentration of the outflow waste liquid to the copper ion concentration of the copper ion-containing waste liquid was ₀ , which was maintained only until the third day, and represents the copper ion of Comparative Example 1 The removal rate of copper ions in the waste liquid was only 100% until the third day. And in Comparative Example 1, the saturation end point was reached by the 23rd day. From this, it can be seen that Example 1 has a better long-term treatment and can remove copper ions in the copper ion-containing waste liquid more effectively.

Example 1 Treatment Method Containing Copper Ion Waste Liquid The total amount of copper ions removed was 127.8 g, and the copper ion unit treatment amount per kg of the iron-aluminum composite metal was 284.0 g. Comparative Example 1 Treatment of copper ion-containing waste liquid The total amount of copper ions removed was 112.4 g, and the copper ion unit treatment amount per kg of iron-aluminum composite metal was 249.8 g. From this, it is understood that Example 1 has a high copper ion unit throughput.

The "copper metal recovery rate" of the method for treating a copper ion-containing waste liquid of Example 1 was 711%. In Comparative Example 1, the "copper metal recovery rate" of the copper ion-containing waste liquid treatment method was 23.2%. From this, it can be seen that Example 1 has a high copper metal recovery rate.

In summary, the method for treating a copper ion-containing waste liquid according to the present invention uses the iron-aluminum composite metal and the seed crystal to make the outflow waste liquid produced by the copper ion waste liquid treatment method weakly acidic to neutral. It meets the discharge water regulation standards and can be discharged directly without any further treatment. Moreover, the treatment method of the copper ion-containing waste liquid does not produce sludge. Further, the method for treating a copper ion-containing waste liquid has a high copper ion unit treatment amount for the copper ion-containing waste liquid, and can long-termly remove copper ions in the copper ion-containing waste liquid, and the surface contains copper metal. The seed crystals are easily separated to recover copper metal, and at the same time, the recovery rate of copper metal is improved, so that the object of the present invention can be achieved.

However, the above is only the embodiment of the present invention, and the scope of the invention is not limited thereto, and all the equivalent equivalent changes and modifications according to the scope of the patent application and the patent specification of the present invention are still The scope of the invention is covered.

Claims (9)

A method for treating a copper ion-containing waste liquid, comprising the steps of: contacting a copper ion-containing waste liquid with an iron-aluminum composite metal and a seed crystal, wherein the seed crystal is at least one selected from the group consisting of quartz sand and garnet sand; Wherein, the iron-aluminum composite metal reduces the copper ions in the copper ion-containing waste liquid to copper element, and the copper element substantially grows on the seed crystal to a seed crystal containing copper metal on the surface. The method for treating a copper ion-containing waste liquid according to claim 1, further comprising the step of separating a seed crystal containing copper metal on the surface from the copper ion-containing waste liquid. The method for treating a copper ion-containing waste liquid according to claim 2, further comprising the steps of: detaching the copper metal from the seed crystal, and recovering the copper metal. The method for treating a copper ion-containing waste liquid according to claim 1, wherein the seed crystal has an average particle diameter ranging from 0.85 mm to 2 mm. The method for treating a copper ion-containing waste liquid according to claim 1, wherein the weight ratio of the iron-aluminum composite metal to the seed crystal is in the range of 1:1 to 5:1. The method for treating a copper ion-containing waste liquid according to claim 1, wherein the iron-aluminum composite metal has an inner layer formed of zero-valent aluminum, and an outer layer covering the outer layer and formed of zero-valent iron, and The total amount of the iron-aluminum composite metal is 100% by weight, the content of the zero-valent aluminum ranges from 75 to 95% by weight, and the content of the zero-valent iron ranges from 5 to 25% by weight. The method for treating a copper ion-containing waste liquid according to claim 1, wherein the iron-aluminum composite metal and the seed crystal are mixed and filled in a reactor, and then the copper ion-containing waste liquid is introduced into the reaction. In the device, the copper ion-containing waste liquid is brought into contact with the iron-aluminum composite metal and the seed crystal. The method for treating a copper ion-containing waste liquid according to claim 7, wherein the flow rate of the copper ion-containing waste liquid introduced into the reactor ranges from 10 to 200 ml/min. The method for treating a copper ion-containing waste liquid according to claim 7, wherein the copper ion-containing waste liquid has a hydraulic retention time in the reactor ranging from 5 to 60 minutes.