JP3162294B2 - Back extraction method for palladium and back extraction method for platinum - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for back-extraction of platinum and palladium, which can be used for the recovery and purification of platinum and palladium. It is about the method.

[0002]

2. Description of the Related Art There are various methods for recovering and refining precious metals such as platinum and palladium, which are dissolved in an acid such as aqua regia and added with a reducing agent to selectively reduce the precious metals. For example, a chemical reduction method has been used. In recent years, recovery and purification methods by a solvent extraction method and an ion exchange method have been developed, but separation of platinum and palladium is not easy even by using these methods. For example, if a high molecular weight amine or anion exchange resin is used, these metals are strongly extracted from hydrochloric acid, but the two are difficult to separate from each other and difficult to back-extract, and the extraction solvent and resin are incinerated. They are also being collected. The ACCO smelter of INCO also proposes a separation / recovery method in which palladium is extracted using dioctyl sulfide and platinum is recovered using TBP. In this case, dioctyl sulfode which is a sulfur compound is used. Has the drawback that during use it is oxidized by oxygen in the air, reducing the extraction capacity and selectivity for palladium. Furthermore, after extracting and recovering palladium with hydroxyoxime, there is a method in which palladium is back-extracted and recovered with a high molecular weight amine, but the hydroxyoxime used in this process is also oxidized by oxygen in the air during use, In addition to the drawback that the extraction capacity is reduced, back extraction is not a capacity.

In order to solve such a prior art, the present inventors have invented a noble metal represented by Chemical formula 1, especially an extractant for platinum and palladium, and a method for separating noble metals (Japanese Patent Laid-Open No. 7-62462). . This extractant was able to efficiently extract platinum and palladium, and further, by selecting conditions, it was possible to separate and extract platinum and palladium. Thus, the extractant represented by Chemical Formula 1 was efficient, but the recovered platinum and palladium existed in the organic solvent phase. In order to make the subsequent recovery operation easier, it has been desired to develop a back extraction method in which the recovered platinum and palladium are further back-extracted into an aqueous phase.

[0004]

An object of the present invention is to solve the above-mentioned problems and to provide a method for efficiently back-extracting platinum and palladium extracted by the extractant represented by Chemical formula 1.

[0005]

Back extraction method for platinum SUMMARY OF THE INVENTION The present invention provides an organic phase containing the extraction agent represented by the extracted of 1 platinum, an aqueous phase of the dithionite salt saturation concentration Contact,
It is characterized by moving platinum into the aqueous phase.

Further, according to the method for back extraction of palladium of the present invention, an organic phase containing an extracting agent represented by Chemical formula 1 in which palladium is extracted is brought into contact with an aqueous phase of a dithionite salt at a saturated concentration. It is characterized in that palladium is moved in.

[0007]

Embodiments of the present invention will be described below, but the present invention is not limited to the following examples.

[0008]

Example 1 Di (2-ethylhexyl) cyanamine was used as an example of the platinum extractant represented by Chemical formula 1. Platinum
73ppm containing 0.1M di (2-ethylhexyl) Shiaminado an aqueous solution of sodium dithionite O / A ratio of a toluene solution and saturated concentration (volume ratio of oil and water phases) is 1:
After shaking for 24 hours, the platinum was back-extracted into the aqueous phase as shown in Table 1.

[0009]

[Table 1]

[0010]

Example 2 Di (2-ethylhexyl) cyanamid was used as an example of the palladium extractant represented by Chemical formula 1.
And an aqueous solution of sodium dithionite O / A ratio of a toluene solution and saturated concentration of palladium in 0.1M containing 95ppm di (2-ethylhexyl) Shiaminado (volume ratio of oil and water phases) is 1: 1 After shaking for 24 hours, palladium was back-extracted into the aqueous phase as shown in Table 2.

[0011]

[Table 2]

[0012]

As described above, according to the method for back extraction of platinum and the method for back extraction of palladium of the present invention, the platinum and palladium extracted by the extractant represented by Chemical Formula 1 can be back-extracted with high efficiency. To facilitate the subsequent recovery operation.

Claims (2)

(57) [Claims] 1. A compound of the general formula (Where R ₁ and R ₂ are alkyl groups having 6 or more carbon atoms)
A method for stripping platinum is extracted in the extracting agent of the platinum represented, is contacted with an organic phase comprising the extracting agent of platinum extracted the platinum, and the aqueous phase dithionite salt saturation concentration And back-extracting platinum into the aqueous phase. 2. A compound of the general formula (Where R ₁ and R ₂ are alkyl groups having 6 or more carbon atoms)
In the method of back-extracting palladium adsorbed on the palladium extractant represented by, the organic phase containing the palladium extractant from which the palladium has been extracted is brought into contact with an aqueous phase of a dithionite salt at a saturated concentration, A method for back-extraction of palladium, comprising moving palladium into an aqueous phase.