TW201425594A - Recycling method of copper-indium-gallium-selenium residual target - Google Patents

Abstract

The present invention is to provide a recycling method of a copper-indium-gallium-selenium residual target, which is to re-synthesize copper-indium-gallium-selenium nano-powder from the filtrate obtained by recycling. The recycling method is to utilize a mixed solution of sulfuric acid and hydrogen peroxide to dissolve the used copper-indium-gallium-selenium residual target and introduce air in the dissolution process or promote the progression of reaction in a water-heating system to enhance its recycling rate. After using sodium sulfite to isolate the residual selenium powder, its copper-indium-gallium mixed solution and the selenium powder can still be used as the precursor solution of the CIGS nano-powder.

Description

Method for recovering copper indium gallium selenide residual target

The invention relates to a method for recovering a copper indium gallium selenide residual target, in particular to a rapid and simple process, which is prepared by a process such as crushing and grinding, sieving, and atmosphere dissolution, wherein a low-cost recycling technology is used in CIGS. The air atmosphere is introduced into the dissolution process, so that the amount of oxidant added is greatly reduced. At the same time, the precipitation of selenium powder is generated first after the dissolution process, so that Se ions can be made into selenium powder and separated only by adding a small amount of reducing agent, and copper indium gallium is separated. The ion mixed solution can still be used to prepare the CIGS powder again.

Both copper indium selenide (CIS) and copper indium gallium selenide (CIGS) are I-III-VI ₂ compound semiconductors, due to their high photoelectric efficiency and low cost materials, and the photocracking effect of amorphous germanium thin film solar cells (Staebler Compared with the -Wronski effect, the stability and radiation resistance of copper indium gallium selenide (CIGS) photovoltaic elements are favored. If compared with cadmium telluride (CdTe) solar cells, CIGS materials have no toxic pollution problem of cadmium. Also more friendly.

At present, the thin film solar cell multilayer film group is mostly prepared by sputtering, so the sputtering target has a direct impact on the properties of each film layer, so the target production research and technology is the most critical process, compared with the evaporation method, the sputtering The method has many advantages, such as (1) composition control is easy; (2) the film has high compactness, and the adhesion is several times that of the evaporation method; (3) the raw material utilization rate is high, and the film is not required to be deposited. Shielding can reduce the pollution of the vacuum chamber; (4) The uniformity of the film is good, suitable for large-area production; however, the manufacturing process of copper indium gallium selenide (CIGS) thin film solar cell by sputtering method The use rate of the target is only about 30%, and the indium gallium metal is a rare precious metal. Therefore, about 70% of the residue still needs to be recycled. Therefore, many upstream and downstream targets are used at home and abroad, and recycled and reprocessed. It has also become one of the key technologies for sustainable development at home and abroad.

According to the world and US patents, a few have proposed CIS/CIGS module recycling projects, and there is no CIS/CIGS recycling related research in academic papers. Nowadays, many scholars have studied the corrosion of chalcopyrite structure CuFeS ₂ . By adding ferric chloride to reduce copper, other scholars have used sodium chloride and sulfuric acid to attack copper. It has also been suggested that both sodium chloride and potassium chloride can promote the erosion reaction of chalcopyrite powder; There are also many recycling methods to choose from. For example, Ag ₂ Se is heat-treated through an atmosphere (300 ° C - 650 ° C). The purpose is to make the structure looser and to form Ag metal through different oxygen partial pressures. After dissolving CIS with SeO ₂ or nitric acid, the elements of Cd, Cu and Se are separated by electrolysis, and then the oxide is formed by oxidation and distillation. After the electrolysis, the dissolved solution of ZnO/InO is formed into a ZnO/InO mixture by distillation. Powder; or completely dissolve CIGS with hydrochloric acid and hydrogen peroxide, first add hydrazine to separate Se powder, and then place copper powder in CIG metal dissolution solution, thereby reducing In metal, and then passing through ion exchange membrane Separate Ga Son, to achieve simple recycling program, in addition, there are also other scholars by solution extraction method whereby the relevant research metal precious metals recycling.

Whether using electrolysis, molecular chelation or extraction, etc., the overall process is complicated. If the metal cation solution of the recovered solution is directly separated from the selenium powder, the CIGS powder is re-prepared by solution synthesis and made into CIGS splash. Plating targets can simplify the process and significantly reduce costs; However, the CIGS chalcopyrite structure powder is not easily dissolved in the acidic solution. According to the Eh-pH relationship diagram of Se in water, this element has a high oxidation potential in a low pH environment, so it is easy to form selenium-rich on the surface of the powder. The barrier layer is easy to dissolve the barrier layer even if the temperature or time is increased, so that the reaction is not easy to carry out. Therefore, a strong oxidizing agent is additionally added during the dissolution process to promote the reaction, however, a large amount of strong oxidizing agent also increases the recovery. The cost of the program, the present invention uses a low-cost recovery method for the dissolution process of copper indium gallium selenide (CIGS), using the ambient atmosphere and a small amount of oxidant to control the dissolution of the sputtering target, and then separating the selenium powder and cation with a reducing agent.

In order to completely dissolve the copper indium gallium selenide residual target in the solution, thereby obtaining high recovery, the present invention completely dissolves by the acid solution method, and then the selenium ion in the dissolved solution is made into selenium powder (Se powder). After separation, the separated recovered filtrate can be converted into a high unit price CIGS nano powder.

The object of the present invention is to provide a low-cost, simple and high-recovery process, and to develop a waste-recovering residual target, a recovery and separation technology, which is more energy-saving than a one-to-one metal, and has a low plant-making cost. And the resource value of the converted CIGS nano powder is high.

The method for recovering the copper indium gallium selenide residual target of the invention is as follows: after the copper indium gallium selenide quaternary target is ground and sieved, the metal powder is immersed in a sulfuric acid solution, wherein the sulfuric acid concentration is 3M-6M The mixed solution contains sulfuric acid and hydrogen peroxide; the mixed solution is passed through air and reacted at 50 ° C for one hour to make copper The indium gallium selenide powder is completely dissolved in the sulfuric acid solution to form a copper indium gallium selenium dissolving filtrate; the sodium sulfite is added to the copper indium gallium selenium dissolving filtrate, and the selenium powder is selectively reduced by the filtrate, and separated to obtain copper indium gallium dissolving. Filtrate and solid selenium powder.

The method for recovering a copper indium gallium selenide residual target according to the present invention, wherein the metal powder is immersed in a sulfuric acid solution, the mixed solution also contains hydrogen peroxide; and the mixed solution is placed under a hydrothermal reaction at 120 ° C to 160 °C and holding the temperature for one to four hours, so that the solution contains copper indium gallium selenium solution and some of the reduced solid selenium powder; adding a small amount of sodium sulfite to reduce the remaining selenium in the copper indium gallium selenium solution and separate it. The copper indium gallium filtrate and the solid selenium powder have a sulfuric acid concentration of 3M~6M.

The method for recovering a copper indium gallium selenide residual target according to the present invention, wherein a volume ratio of sulfuric acid to hydrogen peroxide of the mixed solution is 30:1 to 10:1.

The method for recovering a copper indium gallium selenide residual target of the present invention, wherein the sodium sulfite has an equivalent weight of about 2 to 5 sodium sulfite.

The method for recovering a copper indium gallium selenide residual target according to the present invention, wherein the air flow rate is from 100 ml/min to 300 ml/min.

The method for recovering a copper indium gallium selenide residual target according to the present invention, wherein the selenium powder reduction and replacement is divided into two stages, the first stage is formed in a closed hydrothermal reaction, and the second stage is added with sodium sulfite to make the filtrate only exist. Copper indium gallium dissolution solution.

The copper indium gallium selenide residual target is completely dissolved by the low concentration of sulfuric acid and the air atmosphere, and the precipitate of the selenium powder is found in the filtrate, and Sodium sulfite reduces the selenium ion to selenium powder, and the selenium powder separation rate can reach 99%. The obtained copper indium gallium mixed ion solution can still be used as a precursor solution for preparing CIGS nano powder. The present invention does not require high temperature process for selenium removal and purification. The process, thus reducing the cost and the ease of construction, can achieve high recovery and separation effects, and can achieve the goal of sustainable resources.

In the process of recovering high-density copper indium gallium selenide residual target, please refer to the first figure. First, the block is ground into powder, and after 200 mesh screening, a relatively uniform powder diameter is obtained, mainly using sulfuric acid. Dissolving, wherein the ratio of powder to sulfuric acid is about 1g: 0.2L, a small amount of hydrogen peroxide (H ₂ O ₂ ) is added during the process, and the volume ratio of hydrogen peroxide to sulfuric acid is about 1:30, and the reaction is carried out at a suitable temperature. After one hour, an appropriate air flow atmosphere is introduced into the reaction solution, and the filtrate after the reaction is centrifuged to separate the precipitate of the selenium powder, and then sodium sulfite is added to the clear filtrate to obtain a precipitate of the selenium powder. The selenium powder precipitate is centrifuged and washed at 6000 rpm, and the CIG ion clear solution is stored to provide a solution for synthesizing the CIGS nanopowder.

In addition, the 3M sulfuric acid concentration is added to a trace amount of hydrogen peroxide, and the reaction is carried out in a hydrothermal reaction at 140 ° C for four hours, and then the filtrate and the selenium powder precipitate are separated by centrifugation to obtain a selenium powder precipitate. After the powder precipitate is washed by centrifugation at 6000 rpm, and the CIG ion clear solution is stored, a solution for synthesizing the CIGS nanopowder can be provided.

[Describe the case and implementation results:]

According to the technology applied by the present invention and the achievable results, the implementation parameters are as follows:

Case number one:

In this embodiment, the CIGS residual target after sputtering is subjected to acid etching dissolution, and after being pulverized and sieved, after reacting for different concentrations of sulfuric acid (1M, 3M, 6M and 12M) for one hour, the undissolved powder is filtered and washed. And after drying, the recovery rate is measured. The second figure shows the change of recovery rate obtained by acid etching of different concentrations of sulfuric acid, indicating that the recovery rate will be slowed down in the later stage of increasing sulfuric acid concentration, however, The change in temperature and time at different sulfuric acid concentrations did not change significantly. In addition, the effect of the air atmosphere was compared at low sulfuric acid concentration (1 M) and reacted at 50 ° C for one hour (as shown in Table 1).

Case 2:

When different levels of hydrogen peroxide were added at a sulfuric acid concentration of 3 M, the amount of recovery was as shown in the third figure, and the solution after the reaction was centrifuged to separate the filtrate and the precipitate, and the precipitate was confirmed by XRD (X-ray diffraction). Most of the materials are selenium phase components and a small amount of incompletely dissolved CIGS powder (as shown in the fourth figure), which shows that the low sulfuric acid concentration and the low hydrogen peroxide addition amount can make the recovery rate reach 90%. The air atmosphere can be recovered to 99%.

Case 3:

When a trace amount of hydrogen peroxide was added at a sulfuric acid concentration of 3 M, and the temperature was maintained at 140 ° C for four hours in a hydrothermal reactor, the filtrate and the precipitate were centrifuged, and the precipitate was confirmed to be a phase component of selenium by XRD. As shown in the fourth figure, then sodium sulfite is added to the clarified filtrate, and the selenium residue is replaced in the filtrate back to the selenium powder, as shown in the fifth, sixth and seventh figures.

In view of the above, the present invention has achieved the intended use and efficacy, and is more desirable and practical than the prior art, but the above embodiments are only specifically described for the preferred embodiment of the present invention. The present invention is not intended to limit the scope of the invention, and all other equivalents and modifications may be included in the scope of the invention covered by the invention.

The first figure shows a flow chart of the recycling method of the present invention.

The second figure shows the amount of change in recovery after acid etching of different sulfuric acid concentrations in the examples of the present invention.

The third figure shows the amount of change in recovery of different hydrogen peroxide contents added to the 3M sulfuric acid concentration in the examples of the present invention.

The fourth figure shows an XRD (X-ray diffraction) pattern obtained by obtaining a precipitate in a normal pressure and a hydrothermal reaction, respectively, according to an embodiment of the present invention.

The fifth figure shows the XRD pattern of the precipitate after adding sodium sulfite to the dissolved filtrate in the embodiment of the present invention.

Figure 6 is a SEM (secondary electron image) diagram showing the addition of sodium sulfite to the dissolved filtrate in the examples of the present invention.

The seventh figure shows the addition of sodium sulfite to the dissolved filtrate after the embodiment of the present invention. EDS (energy dispersion) map.

Claims (7)

The method for recovering copper indium gallium selenide residual target is as follows: after the copper indium gallium selenide quaternary target is ground and sieved, the metal powder is immersed in a sulfuric acid solution, wherein the sulfuric acid concentration is 3M~6M; The mixed solution comprises sulfuric acid and hydrogen peroxide; the mixed solution is passed through air and reacted at 50 ° C for one hour, so that the copper indium gallium selenide powder is completely dissolved in the sulfuric acid solution to form a copper indium gallium selenium dissolved filtrate; The copper indium gallium selenium dissolves the filtrate, and the selenium powder is selectively reduced by the filtrate, and is separated to obtain a copper indium gallium dissolving filtrate and a solid selenium powder. The method for recovering a copper indium gallium selenide residual target according to claim 1, wherein the metal powder is immersed in a sulfuric acid solution, and the mixed solution further comprises hydrogen peroxide; the mixed solution is placed in a hydrothermal reaction. The temperature is maintained at 120 ° C ~ 160 ° C for one to four hours, so that the solution contains copper indium gallium selenium solution and some of the reduced solid selenium powder; a small amount of sodium sulfite is added to reduce the remaining selenium in the copper indium gallium selenium solution And separating, obtaining a copper indium gallium filtrate and a solid selenium powder. The method for recovering a copper indium gallium selenide residual target according to claim 2, wherein the sulfuric acid concentration is 3M~6M. The method for recovering a copper indium gallium selenide residual target according to claim 1 or 2, wherein a volume ratio of sulfuric acid to hydrogen peroxide of the mixed solution It is 30:1~10:1. The method for recovering a copper indium gallium selenide residual target according to claim 1 or 2, wherein the sodium sulfite has an equivalent weight of about 2 to 5 sodium sulfite. The method for recovering a copper indium gallium selenide residual target according to claim 1, wherein the air flow rate is from 100 ml/min to 300 ml/min. The method for recovering a copper indium gallium selenide residual target according to claim 2, wherein the selenium powder reduction and replacement is divided into two stages, the first stage is formed in a closed hydrothermal reaction, and the second stage is added with sodium sulfite. Only the copper indium gallium dissolving solution was present in the filtrate.