KR101155308B1 - Enrichment of rutenium from the rutenium containing waste scraps by nitric acid leaching - Google Patents

Abstract

The present invention is to increase the concentration of ruthenium by increasing the concentration of ruthenium by leaching other metal components other than the ruthenium from the waste scrap by adding a nitric acid solution to the waste scrap containing ruthenium (Ru) and other metal components and reacting with filtration. It relates to a ruthenium enrichment method characterized by.

Using the nitrate leaching method of the present invention, lead (Pb), barium (Ba), silver (Ag), bismuth (Bi), aluminum (Al), cobalt (Co), zinc (Zn) and iron from ruthenium-containing waste scrap It is possible to leach and remove metal components other than ruthenium, such as (Fe), thereby making it possible to concentrate ruthenium which shows high added value as a rare platinum group.

Ruthenium, waste scrap, nitrate leaching

Description

Enrichment of rutenium from the rutenium containing waste scraps by nitric acid leaching}

The present invention relates to a method for concentrating ruthenium using nitrate leaching from ruthenium-containing waste scrap, and more specifically, by adding nitric acid solution to waste scrap containing ruthenium and other metal components, and reacting with filtration to wash the waste scrap. It relates to a ruthenium concentration method characterized by increasing the concentration of ruthenium by leaching other metal components other than ruthenium.

Ruthenium is a chemical element with the symbol Ru, atomic number 44 and a rare transition metal belonging to the Platinum group, produced together from platinum ores, polished silver white metal, hard and brittle. When heated in air or oxygen, it is oxidized to form blue ruthenium dioxide (RuO ₂ ), and some of it is volatilized as ruthenium tetraoxide (RuO ₄ ), extremely stable in acid and insoluble in aqua regia, but with potassium hydroxide Heating a mixture of potassium nitrate corrodes.

The commercial recovery and application of ruthenium began in the 1950s with the technology of extracting ion exchange resins from high-level liquid wastes in the United States in the 1950s. As super-capacity characteristics were developed and demand increased, it separated and refined from platinum ore, focusing on resource-owned countries, and advanced to mass supply and applied research.

Since the 1990s, interest in platinum group recovery technologies has increased in Germany, the United Kingdom, the United States, and Japan, and commercial processes have been in place to separate and purify ruthenium from platinum ore and secondary waste resources. At present, the platinum group is recovered from scrap commercially in China besides Heraeus, Johnson Matthey, INCO, Japan and Tanaka Metal in Japan. The study of ruthenium recovery in Korea has only been reported in 1998 by the Atomic Energy Research Institute with the ion exchange resin method and from the Korea Institute of Geoscience and Mineral Resources.

Ruthenium, like the platinum group elements, is produced and separated and recovered, so it has been confined to some countries where technology owners own ores. Recently, however, there has been an active movement to recover such metals from secondary sources such as electronic scrap. Ruthenium-containing waste resources exist in various types such as waste sconce, waste paste, and process sludge.

In the present invention, the study was focused on the recovery of ruthenium from the waste resources (waste scrap).

The waste scrap is incinerated and discharged in the form of incineration ash. In order to recover ruthenium from the incineration ash, it is preferable to selectively leach ruthenium and recover it. However, ruthenium metal exhibits poorly soluble properties to acid among the platinum group elements, which makes the recovery process difficult. Ruthenium metals have been reported to dissolve under conditions of supplying chlorine gas under sodium hypochlorite (NaOCl) solution. In the case of ruthenium oxide, the alkali melting method has been studied and applied classically.

However, when the incineration is directly dissolved, the content of impurities is large and the purification process is complicated. Therefore, it is desirable to concentrate ruthenium by removing impurities such as lead (Pb) in advance, and then dissolve and recover ruthenium with high efficiency.

Accordingly, the present inventors investigated the effect of the basic factors on the leaching of these metals in order to leach out impurities such as lead (Pb), barium (Ba), zinc (Zn) from ruthenium-containing waste scrap incinerators. When leaching with HNO ₃ ) it was confirmed that ruthenium can be concentrated by removing the impurities as described above to complete the present invention.

Accordingly, a main object of the present invention is to provide a method of concentrating high value added ruthenium as a rare platinum group by removing impurities such as lead (Pb), barium (Ba), and zinc (Zn) from discarded waste scrap containing ruthenium. .

According to an aspect of the present invention, the present invention provides a ruthenium concentration by leaching other metal components other than the ruthenium from the waste scrap by adding nitric acid solution to the waste scrap containing ruthenium and other metal components, and reacting with filtration. It provides a ruthenium enrichment method characterized by increasing the concentration.

In the ruthenium enrichment method of the present invention, the waste scrap includes ruthenium including lead (Pb), barium (Ba), silver (Ag), bismuth (Bi), aluminum (Al), cobalt (Co), zinc (Zn) Or it may contain a metal component such as iron (Fe), it can be removed from the waste scrap by leaching metal components other than the ruthenium as described above by the method of the present invention.

In the ruthenium concentration method of the present invention, the nitric acid solution is preferably used 10 to 15% (v / v) nitric acid solution.

In the ruthenium concentration method of the present invention, the reaction is preferably made for 30 to 90 minutes at 60 to 80 ℃.

In the ruthenium concentration method of the present invention, it is preferable to use hot water of 60 to 80 ℃ at the time of washing.

Hereinafter, the method for concentrating ruthenium using nitric acid leaching from the ruthenium-containing waste scrap of the present invention will be described in more detail step by step.

The present invention relates to a method for recovering ruthenium, a platinum group precious metal, from industrially generated waste scraps, by leaching and removing metal components other than ruthenium by using nitric acid by using the poorly soluble properties of ruthenium acid. It is an invention that establishes the factors and optimum conditions according to the nitrate leaching of each metal component.

In the present invention, the waste scrap is an industrial waste resource generated in the form of waste sconce, waste paste, process sludge, etc. In the present invention, it may be used as a target material for recovering ruthenium, which is a rare transition metal belonging to the platinum group. Such waste scraps are generally incinerated and discharged in the form of incineration ash. If the waste scraps are not incinerated, it is preferable to remove unnecessary combustible components through incineration.

The waste scrap may include metals such as lead, barium, silver, bismuth, aluminum, cobalt, zinc, or iron, including ruthenium, and in the present invention, metals as described above other than ruthenium which are impurities using nitric acid. By dissolving the component and filtering it, it is possible to concentrate ruthenium by separating impurities from the waste scrap.

Ruthenium is difficult to dissolve in nitric acid because it shows poorly soluble properties in the acid is present in a solid state. Therefore, when nitric acid is treated in waste scrap, impurities are dissolved in nitric acid and exist in the liquid state. Ruthenium is not dissolved and exists in the solid state. When only the solid state is recovered through filtration, impurities are removed. As a result, a ruthenium-enriched residue can be obtained.

In the present invention, the nitric acid solution is preferably used 10 to 15% (v / v) nitric acid solution. This is because the leaching rate for the above-mentioned metal components such as lead, barium, silver, bismuth, aluminum, cobalt, zinc or iron is the highest when using the nitric acid solution of the above concentration.

In the present invention, the reaction of the nitric acid solution and waste scrap is preferably made for 30 to 90 minutes at 60 to 80 ℃. This is because the solubility of each metal component in nitric acid varies depending on the reaction temperature, and the reaction is performed for a suitable time so that the metal components of the nitric acid solution and the waste scrap are sufficiently reacted. Particularly, when the temperature is lower than 60 ° C, the solubility of the metal components in the nitric acid is lowered, so that it does not dissolve in nitric acid and remains in a solid state. Therefore, the temperature is preferably maintained at 60 ° C or higher. Do.

Accordingly, the washing process is also preferably using hot water of 60 to 80 ℃. This is to prevent the crystallization due to the low temperature during the washing process of the metal component dissolved in the nitric acid remaining without being completely filtered during the filtration process. If the temperature is lowered during the washing process and the metal component dissolved in the nitric acid is crystallized, the concentration efficiency may decrease because it remains with ruthenium during the filtration process.

Hereinafter, the present invention will be described in more detail with reference to Examples. These embodiments are only for illustrating the present invention, and thus the scope of the present invention is not construed as being limited by these embodiments.

Example 1.Nitrate leaching using 25% nitric acid solution

Ruthenium-containing waste scrap used in the embodiment of the present invention was obtained from S as a waste plasma display panel (PDP) electrode paint incinerator, and a solid mill and a rotating ultra-fine atomizer for vibrating solid mass samples at high speed. It was pulverized by using the apparatus and sieved and then adjusted to a size of 250 mesh or less to prepare an incineration ash powder (hereinafter referred to as incineration ash).

In this embodiment, a device capable of stirring while maintaining a constant temperature as shown in FIG. 1 was used for nitric acid leaching, and 1 g of 25% (v / v) nitric acid solution was added to 250 g of incineration ash, and then 60 ° C. using the apparatus of FIG. 3. Mix for 1 hour.

The mixture was filtered to give a leach residue (solid that did not pass the filter) and a leachate (liquid that passed through the filter).

Example 2. Nitric Acid Leaching Using 5% Nitric Acid Solution

Nitric acid leaching was carried out in the same manner as in Example 1 using 5% nitric acid solution, and washed with hot water at 60 ℃ after filtration.

Example 3. Nitric Acid Leaching Using 7% Nitric Acid Solution

Nitric acid leaching was carried out in the same manner as in Example 2 using 7% nitric acid solution.

Example 4. Nitric Acid Leaching Using 10% Nitric Acid Solution

Nitric acid leaching was carried out in the same manner as in Example 2 using a 10% nitric acid solution.

Example 5. Nitric Acid Leaching Using 15% Nitric Acid Solution

Nitric acid leaching was carried out in the same manner as in Example 2 using a 15% nitric acid solution.

Example 6. Nitric Acid Leaching Using 20% Nitric Acid Solution

Nitric acid leaching was carried out in the same manner as in Example 2 using a 20% nitric acid solution.

Experimental Example 1. Component Analysis of Ruthenium-Containing Waste Scrap Samples

It was measured by SQX (Semi-quantitative X-ray) to identify the components of the incineration ash used in the above example, X-ray diffraction (XRD) for qualitative analysis.

[Table 1]

Ingredient result unit Det.limit El. line Intensity w / o normal Na ₂ O 0.0000 mass% 0.0086 Na-KA 0.2298 0.0000 MgO 0.0084 mass% 0.0041 Mg-KA 0.0791 0.0080 Al ₂ O ₃ 0.7336 mass% 0.0020 Al-KA 15.6094 0.6977 SiO ₂ 30.2310 mass% 0.0061 Si-KA 552.7943 28.7494 P ₂ O ₅ 0.0697 mass% 0.0012 P-KA 2.6992 0.0663 Cl 0.1388 mass% 0.0060 Cl-ka 1.2578 0.1320 K ₂ O 0.0072 mass% 0.0018 K-KA 0.1872 0.0068 CaO 0.0413 mass% 0.0024 Ca-KA 0.8640 0.0393 TiO ₂ 0.0824 mass% 0.0055 Ti-KA 0.3699 0.0783 Fe ₂ O ₃ 0.3189 mass% 0.0020 Fe-ka 9.3621 0.3032 Co ₂ O ₃ 0.5176 mass% 0.0017 Co-ka 21.0440 0.4923 NiO 0.0241 mass% 0.0013 Ni-KA 1.5272 0.0230 CuO 0.0225 mass% 0.0011 Cu-KA 1.8272 0.0214 ZnO 0.2861 mass% 0.0010 Zn-KA 30.7341 0.2721 ZrO ₂ 0.2939 mass% 0.0012 Zr-KA 35.3402 0.2795 RuO ₂ 15.1712 mass% 0.0066 Ru-ka 47.4239 14.4277 Rh ₂ O ₃ 0.0000 mass% 0.0065 Rh-KA 0.0621 0.0000 Ag ₂ O 0.5818 mass% 0.0138 Ag-KA 4.6747 0.5533 BaO 0.9687 mass% 0.0119 Ba-LA 1.9086 0.9212 HgO 0.0227 mass% 0.0028 Hg-LA 1.2039 0.0216 PbO 49.6934 mass% 0.0190 Pb-LA 71.3880 47.2581 Bi ₂ O ₃ 0.7868 mass% 0.0045 Bi-la 43.5070 0.7483

As a result of SQX measurement of incineration ash, as shown in Table 1, ruthenium was found to contain 14.43%, and lead (Pb) was the highest as 47.26%, followed by silicon (Si). In addition, it was confirmed that barium (Ba), bismuth (Bi), silver (Ag), zinc (Zn), cobalt (Co), iron (Fe).

As a result of XRD measurement of the incineration ash, as shown in FIG. 2, many peaks were identified. As a result of analyzing the main peaks, ruthenium was present in a mixed state of Ru, Pb ₂ (Ru 1.69, Pb 0.31), and RuO ₂ . In the case of Si, which was found to be the second largest as a result of SQX measurement, it was difficult to discriminate by XRD measurement.

Experimental Example 2. Analysis of precipitate component of leachate after leaching of nitric acid

In case of nitric acid leaching, it is classified into leach residue and leach liquor due to filtration process.

In this Example, the leaching solution obtained in Example 1 was measured by Wavelength Dispersive X-ray (WDX) to identify the components of the precipitate, which occurs as the coolant is cooled to room temperature.

As a result, it was confirmed that the components of the precipitate as lead nitrate, as shown in Figs. This means that the solubility of lead nitrate has a significant effect on lead leaching. This phenomenon is that when nitrate leaching is carried out, most of the lead component is dissolved in nitric acid at 60 ° C, but when the temperature goes down to saturation, it is below the saturation temperature. This is because it precipitates as lead nitrate crystals in.

Therefore, in order to clean the lead component by using nitric acid leaching from ruthenium-containing waste scrap such as incineration ash, it is necessary to maintain the temperature so that crystals do not precipitate in advance in the process of filtering after reaction with nitric acid solution. Hot water is recommended for cleaning to remove the remaining nitric acid leaching solution.

Experimental Example 3. Component Analysis of Leachate

In order to identify the components of the leachate obtained in Examples 2 to 6 were analyzed using an ICP-AES (Inductively Coupled Plasma-Atomic Emission Spectrometry).

As confirmed in Experiment 1, when the amount of each metal component contained in the incineration ash before nitric acid leaching to 100%, the amount of each metal component contained in the leaching liquid after nitric acid leaching to the amount before the nitric acid leaching Calculated in% expressed as leaching rate.

Leaching Rate (%) = (B-A) / B × 100

A: amount of specific metal component contained in incineration ash after nitrate leaching (g)

B: amount of specific metal component contained in incineration ash before nitrate leaching (g)

As a result, as shown in Figure 5, it was confirmed that the leaching rate of the metal components such as lead, barium, silver, zinc, bismuth, and cobalt is relatively high, in the case of lead that occupies most of the impurities in 7 to 20% nitric acid solution The rate was high and then the leaching rate decreased again due to the formation of lead nitrate. It was also confirmed that other elements other than lead also had a high leaching rate in 10% to 15% nitric acid solution. These results are shown in Table 2 numerically.

TABLE 2

Concentration of nitric acid solution 5% 7% 10% 15% 20% Lead leaching amount (g) 9.40 9.62 10.12 10.41 10.28 Lead leaching rate (%) 79.56 81.49 85.73 88.18 87.05 Leaching amount of metal components other than lead (g) 1.72 1.72 1.72 1.72 1.72 % Leaching of total metals 44.48 45.36 47.36 48.52 48.00

On the other hand, as shown in Figure 5, it was confirmed that the ruthenium is rarely leached.

In addition, in Experimental Example 2, it was confirmed that the solubility of lead nitrate has a great influence on lead leaching, and thus, the solubility curve of lead nitrate and the actual lead leaching rate were compared.

The leaching behavior of lead by nitric acid should theoretically be equal to the equivalent and solubility lines shown in FIG. However, although the actual lead leaching rate is similar to the equivalence and solubility curves, it is confirmed that the results are different from the theoretical ones because they are not exactly the same.

This phenomenon may be due to the fact that lead is present as some other metal and intermetallic compound, and the leaching rate was decreased slightly, or the nitric acid leaching mixture, which was maintained at 60 ° C, dropped to 47 ° C and precipitated as lead nitrate.

Experimental Example 4. Component Analysis of Leaching Residues

The components of the incineration ash and the leach residues obtained in Examples 2 to 5 were analyzed by XRD.

As a result, as shown in FIG. 7, it was confirmed that the main components of the residue were composed of SiO ₂ , Ru, RuO _2, and Pb ₂ Ru ₂ O ₆ .

This means that most of the impurity components have been removed from the incineration ash, that is, ruthenium-containing waste scrap, by nitrate leaching.

Experimental Example 5. Weight Loss Measurement

After nitrate leaching, the weight loss was measured to confirm the weight change of the incineration ash due to the elution of each metal component.

The weight loss was investigated by measuring the weight of the incineration ash and the leach residues of Examples 2 to 6.

[Table 3]

Concentration of nitric acid solution 5% 7% 10% 15% 20% Ash weight before leaching (g) 25.0 25.0 25.0 25.0 25.0 Weight of incineration ash after leaching (g) 12.74 11.70 11.61 11.05 11.70 Loss incineration weight after leaching (%) 49.04 53.21 53.56 55.78 53.2

As a result, as shown in Table 3, it was confirmed that the weight of the incineration ash is significantly reduced due to nitric acid leaching.

This means that the weight of the original incineration was reduced because a significant amount of impurity components such as lead were leached due to nitric acid leaching.

As described above, by using the nitrate leaching method of the present invention, it is possible to leach and remove metal components other than ruthenium such as lead, barium, silver, bismuth, aluminum, cobalt, zinc, and iron from ruthenium-containing waste scrap. As a result, it is possible to concentrate ruthenium showing high added value.

1 is a graph showing the XRD analysis of the waste PDP electrode paint incinerator used in the embodiment.

Figure 2 is a view showing the nitric acid leaching experiment apparatus used in the embodiment.

Figure 3 is a graph showing a photograph of the leaching residue and its analysis after 25% nitric acid leaching.

Figure 4 is a graph showing the XRD analysis of the leaching residue after 25% nitric acid leaching.

5 is a graph showing the leaching rate of each metal according to the change in nitric acid concentration.

6 is a graph showing the solubility of lead nitrate and the leaching rate of lead according to the concentration of nitric acid.

7 is a graph showing the XRD analysis results of incineration ash before nitric acid leaching and leach residue after nitric acid leaching according to each concentration.

Claims (5)

The ruthenium concentration is increased by leaching other metal components other than the ruthenium from the scrap by adding 10 to 15% (v / v) nitric acid solution to the waste scrap containing ruthenium and other metal components, followed by filtration and washing. Ruthenium concentration method characterized in that the concentration. The method of claim 1, wherein the other metal component comprises at least one selected from the group consisting of lead, barium, silver, bismuth, aluminum, cobalt, zinc, and iron. delete By adding nitric acid solution to waste scrap containing ruthenium and other metal components, reacting for 30 to 90 minutes at 60 to 80 ° C., and filtering and washing to increase the ruthenium concentration by leaching other metal components other than the ruthenium from the waste scrap. Ruthenium concentration method characterized in that the concentration. By adding nitric acid solution to the waste scrap containing ruthenium and other metal components and reacting and washing with hot water at 60-80 ° C. after filtration, the ruthenium concentration is increased by leaching other metal components other than the ruthenium from the waste scrap. Ruthenium concentration method characterized in that the concentration.

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