KR102136456B1 - Recovering method of gold from a leach solution of anode slime - Google Patents

Abstract

The present invention relates to a method for recovering gold (Au) contained in a hydrochloric acid leachate of an anode slime with high purity using a solvent extraction method.
In the method according to the present invention, di-2,4,4-trimethylpentyl phosphinic acid (Di-2,4,4-trimethylpentyl phosphinic acid) is added to a hydrochloric acid leachate containing Au(III) and Sn(II). Selectively extracting Au(III) and Sn(II) using an extraction solvent, and using at least one stripping agent selected from (NH ₂ ) ₂ CS, NH ₄ Cl and (NH) ₂ S ₂ O ₃ By selectively removing Au(III) from Di-2,4,4-trimethylpentyl phosphinic acid from which Au(III) and Sn(II) were extracted, It characterized in that it comprises a step of separating.

Description

Recovery method of gold in leaching solution of anode slime {RECOVERING METHOD OF GOLD FROM A LEACH SOLUTION OF ANODE SLIME}

The present invention relates to a method for recovering gold (Au) contained in a hydrochloric acid leachate of an anode slime with high purity using a solvent extraction method.

Anode slime is a by-product of the electrical refining of some metals, such as copper, lead, and tin, and is rich in precious metals, making it an important auxiliary resource for precious metals.

Regarding the recovery of metal resources, some non-metals are removed from the anode slime by pretreatment such as melting and selective leaching to make concentrated slime, and various media are used to leach the components contained in the anode slime, and then solvent Separation and recovery of metals contained in the leachate may be performed through methods such as extraction, ion exchange, bio-leaching, and bio-adsorption. Among these, solvent extraction has various advantages over other methods.

On the other hand, the hydrochloric acid leachate of the anode slime includes gold (Au), copper (Cu), nickel (Ni), silver (Ag), tin (Sn), and zinc (Zn). A method of separating and recovering (Au) with high purity is required.

Republic of Korea Patent Publication No. 2013-0041080

An object of the present invention is to provide a method of separating and recovering gold (Au) contained in a hydrochloric acid leaching solution of an anode slime in a high purity state using a solvent extraction method.

In order to solve the above problems, the present invention is di-2,4,4-trimethylpentyl phosphinic acid (Di-2,4,4-trimethylpentyl phosphinic) in a hydrochloric acid leachate containing Au(III) and Sn(II). acid) as an extraction solvent to selectively extract Au(III) and Sn(II), and stripping of one or more selected from (NH ₂ ) ₂ CS, NH ₄ Cl and (NH) ₂ S ₂ O ₃ Using agent, Au(III) is selectively selected from Di-2,4,4-trimethylpentyl phosphinic acid from which Au(III) and Sn(II) are extracted. It provides a method for recovering gold from the hydrochloric acid leachate comprising the step of separating and separating.

According to the method according to the invention, gold (Au) from the hydrochloric acid leachate of the anode slime containing gold (Au), silver (Ag), copper (Cu), zinc (Zn), nickel (Ni) and tin (Sn), etc. ) Can be separated and recovered with high purity.

1 is a process diagram for the recovery of gold contained in the leaching solution according to a preferred embodiment of the present invention.
Figure 2 shows the difference in extraction rate (%) according to the concentration of HCl in the leachate when extracting using 0.2M of Cyanex 272.
Figure 3 shows the difference in the extraction rate (%) when different concentrations of Cyanex 272 applied to the leachate having a HCl concentration of 5M.
4 shows the change of the stripping rate (%) according to the (NH ₂ ) ₂ CS concentration.
5 shows the change of the stripping rate (%) according to the (NH) ₂ S ₂ O ₃ concentration.
Figure 6 shows the change in the stripping rate (%) according to the NH ₄ Cl concentration.

Hereinafter, with reference to the accompanying drawings for the embodiment of the present invention will be described the configuration and operation. In the following description of the present invention, when it is determined that a detailed description of related known functions or configurations may unnecessarily obscure the subject matter of the present invention, the detailed description will be omitted. Also, when a part is said to “include” a certain component, this means that other components may be further included rather than excluding other components, unless otherwise stated.

The method for recovering gold (Au) contained in the leaching solution of the anode slime according to the present invention includes the following two steps.

(1) Au(III) using di-2,4,4-trimethylpentyl phosphinic acid as an extraction solvent in a hydrochloric acid leachate containing Au(III) And extracting at least one other metal together

(2) Di-2,4,4-trimethylpentyl phosphinic acid (Di-2,4, extracted with at least one other metal together with Au(III) using (NH ₄ ) ₂ S ₂ O ₃ Step of selectively removing Au(III) from 4-trimethylpentyl phosphinic acid) to separate from other metals

In the present invention, the di-2,4,4-trimethylpentyl phosphinic acid (Di-2,4,4-trimethylpentyl phosphinic acid) may be, preferably, the trade name Cyanex 272.

The hydrochloric acid leachate may further include Ag(I), Cu(II), Ni(II), Sn(II) and Zn(II) in addition to Au(III).

If the concentration of hydrochloric acid in the hydrochloric acid leachate is less than 0.5M, the extraction efficiency is low, so it is preferable to be 0.5M or more. If it is lower than 3M, 3M or more is most preferable because an emulsion or a third phase may be generated. The upper limit of the hydrochloric acid concentration is not particularly limited, but it is economical to make the extraction efficiency less than 9M even if it is higher.

When extracting Au(III) using the di-2,4,4-trimethylpentyl phosphinic acid, Sn(II) may be extracted together.

Since the concentration of di-2,4,4-trimethylpentyl phosphinic acid is less than 0.1M, the extraction rate is low, and even if it exceeds 0.2M, there is no significant change in the extraction rate, so 0.1 Although preferably 0.2M, although the concentration of the extractant is high, there is no problem in recovering gold (Au), but the above composition range is preferable in terms of recovery efficiency and economic efficiency.

The hydrochloric acid leachate may include Ag(I), Cu(II), Ni(II), Sn(II) and Zn(II).

The stripping agent may be (NH) ₂ S ₂ O ₃ , wherein when the concentration of (NH) ₂ S ₂ O ₃ exceeds 0.5M, the removal rate of Cu(II) is increased and the recovered Au(III) solution Since it is possible to lower the purity of, it is preferable to maintain below 0M and below 0.5M, and since the removal efficiency is low below 0.1M, 0.1M to 0.5M is more preferable.

The stripping agent may be (NH ₂ ) ₂ CS, and when the concentration of (NH ₂ ) ₂ CS exceeds 0.9M, the stripping rate of Cu(II) is increased to lower the purity of the recovered Au(III) solution. Since it can be, it is preferable to maintain more than 0M to 0.9M or less, and since the removal efficiency is low at 0.01M or less, 0.01M to 0.9M is more preferable.

The stripping agent may be NH ₄ Cl, and when the concentration of NH ₄ Cl exceeds 1.0 M, the removal rate of Cu(II) may be increased, thereby reducing the purity of the recovered Au(III) solution, and thus exceeding 0M 1.0 It is preferable to keep it below M, and since the removal efficiency is low at 0.3M or less, 0.3M to 1.0M is more preferable.

[Example]

Preparation of anode slime synthetic solution

HAuCl ₄ (30% by weight dilute HCl, Sigma-Aldrich), CuCl ₂ ·2H ₂ O (97%, Daejung Chemical), SnCl ₂ ·2H ₂ O (97%, Daejung Chemical), AgCl (99.5% Daejung Chemical), ZnCl ₂ (90%, Deoksan Chemical), NiCl ₂ ·6H ₂ O (96%, Yakurisun Chemical) was dissolved in distilled water to prepare a solution simulating the metal component contained in the anode slime leaching solution. When preparing the solution, a small amount of H ₂ O ₂ (30%, Daejung Chemical) was added to suppress the formation of particulate precipitates. The acidity of the solution was adjusted by adding hydrochloric acid. The composition of the metal component included in the solution prepared through the above process is shown in Table 1 below.

ingredient Cu Zn Ni Ag Sn Au content
(mg/l) 2680 18 25 55 450 100

Calculation of extractant and extraction rate and removal rate

The extractant used in the present invention was used without separate purification, and kerosene (Daejung Chemical) was used as a diluent for the extractant.

The solvent extraction and stripping process was performed by mixing the same volume (20 mL) of the organic phase and the aqueous phase, stirring for 30 minutes using a stirrer, and separating using a separatory funnel in an equilibrium state. 25±1°C).

In addition, the concentration of metal ions in the aqueous phase before and after extraction was measured using ICP-AES equipment, and the concentration of metal ions in the organic phase from which metal ions were extracted was calculated by mass balance. Through the solvent extraction test, the extraction rate and stripping rate of each component were calculated through [Equation 1] and [Equation 2] below.

[Equation 1]

Extraction rate (%) = (equilibrium mass of metal in organic phase)/(initial mass of metal in aqueous solution before extraction) x 100

[Equation 2]

Removal rate (%) = (Equilibrium mass of metal in aqueous solution after removal)/(Initial mass of metal in organic phase before removal)×100

Recovery of gold (Au)

1 shows a process diagram according to a preferred embodiment of the present invention. As shown in Figure 1, the process according to a preferred embodiment of the present invention, the step of extracting the Au (III) contained in the anode slime leach using an extractant, and other metals extracted with Au (III) And selectively removing Au(III) from the extractant containing the component to make a pure Au(III) solution.

(1) Extraction of Au(III)

In the present invention, Cyanex 272 was used as an extractant to separate Au(III) contained in the leachate of the anode slime.

Figure 2 shows the difference in the extraction rate (%) according to the HCl concentration of the leach, when extracting using 0.2M Cyanex 272. Figure 2 is the organic phase / water volume ratio (O / A) is performed under the conditions of 1, stirring time 30 minutes.

2, when the concentration of HCl is 0.5M, when Cyanex 272 is used, most of Sn(II) is extracted, and about 50% of Au(III) is extracted, but when the concentration of HCl is 1M or more, The extraction rate of Sn(II) decreases to 90%, whereas the extraction rate of Au(III) increases to over 99%. On the other hand, even if the concentration of HCl increases above 1M, the extraction rate of Au(III) increases slowly but remains almost unchanged. That is, when the concentration of HCl is 0.5M or more, a certain degree of extraction can be obtained, and if it is 1M or more, it has an efficiency capable of extracting most of Au(III), so it is more preferable to be 1M or more.

On the other hand, although the extraction amount of Ag(I), Ni(II), and Cu(II) was lower than 5% in the entire concentration range of the tested HCl, it was confirmed that these components were also extracted. In addition, when the HCl concentration was lower than 3M, emulsification or generation of a third phase was observed.

Figure 3 shows the difference in the extraction rate (%) when the concentration of Cyanex 272 in the leachate having a HCl concentration of 5M. 3, the organic phase / water volume ratio (O / A) is 1, the stirring time 30 minutes, Cyanex 272 concentration is carried out under the conditions of 0.01 ~ 0.2M.

As shown in Fig. 3, even if the concentration of Cyanex 272 was changed, the extraction behavior of Au(III) and Sn(II) was almost the same. The extraction rate of the two components tends to increase linearly as the concentration of Cyanex 272 increases, but increases slowly after 0.1M, and shows an extraction rate of almost 100% above 0.2M. In other words, in the case of Cyanex 272, it is preferable to use 0.2M in terms of cost since no further improvement in extraction rate can be expected even if it exceeds 0.2M.

Table 2 below shows the results of the component analysis of the extracted filtrate after performing 2-step counter-current for 30 minutes under the conditions of Cyanex 272 0.2M and HCl 5M.

ingredient Cu Zn Ni Ag Sn Au content
(mg/l) 2595 17.3 24.5 53.8 45.5 0.5

As shown in Table 2, through two-stage extraction through the use of Cyanex 272, Au(III) was completely extracted, and at least about 95% Sn(II) was extracted, and almost no extract was extracted. Cu(II), Zn(II), Ni(II), and Ag(I) remain.

(2) Selective removal of Au(III)

In the extraction using Cyanex 272, Sn(II) is selectively extracted together with Au(III), and a small amount of Cu(II), Zn(II), Ni(II), and Ag(I) can also be extracted. Therefore, in order to separate pure Au(III) from the extractant, selective stripping of Au(III) is required.

Through the extraction process of Au(III), the extracted Cyanex 272 contains 99.5mg/L Au(III) and 406.5mg/L Sn(II), and other 1.5mg/L Ag( I), 85mg/L Cu(II), and 0.2mg/L Zn(II) are contained in a small amount.

Table 3 below shows the types and stripping rates of various stripping agents used for stripping of Au(III).

Stripper density
(M) Removal rate (%) Cu Zn Ni Ag Sn Au HCl One 0.8 100 0 0 0 3.8 NH ₄ SCN One 8.8 100 0 0 4.3 80.9 (NH ₂ ) ₂ CS One 7 100 0 0 0 100 NH ₄ Cl One 6.5 100 0 0 0 100 (NH) ₂ S ₂ O ₃ 0.5 5.5 100 0 0 0 100

As shown in Table 3, it is confirmed that (NH ₂ ) ₂ CS, NH ₄ Cl and (NH) ₂ S ₂ O ₃ can selectively remove Au(III) 100% without removing Sn(II). . In addition, (NH ₂ ) ₂ CS, NH ₄ Cl and (NH) ₂ S ₂ O ₃ are stripped together with Cu(II) where most of Zn(II) exhibits a stripping rate of about 7% or less. That is, (NH ₂ ) ₂ CS, NH ₄ Cl, and (NH) ₂ S ₂ O ₃ may be used for selective separation of Au(III) and Zn(II).

4 shows the change of the stripping rate according to the concentration of (NH ₂ ) ₂ CS. At this time, the solution used for the stripping was the extraction liquid extracted with Au(III), and the concentration of (NH ₂ ) ₂ CS was 0.3 to 1M, the O/A ratio 1, and the stripping time 30 minutes.

As shown in FIG. 4, (NH ₂ ) ₂ CS concentration was found to be 100% Au(III) and Zn(II) stripped over the entire range tested, and in the case of Cu(II), 0.9M or less A stripping rate of 5% or less appears. Considering that the extraction amount of Cu(II) is relatively higher than that of Zn(II) in the extraction process of Au(III), to increase the purity of Au(III) after removal, the (NH ₂ ) ₂ CS concentration is 0.9M or less. desirable.

5 shows the change of the stripping rate according to the (NH) ₂ S ₂ O ₃ concentration. At this time, the solution used for the stripping was an extraction liquid extracting Au(III), and the concentration of (NH) ₂ S ₂ O ₃ was 0.1 to 0.5M, the O/A ratio 1, and the stripping time 30 minutes.

5, Zn(II) was 100% stripped in the range of (NH) ₂ S ₂ O ₃ concentration of 0.1 to 0.5M, but 100% stripping was possible in the case of Au(III) 0.5M or more. Did. That is, a concentration of 0.5M or more is preferable for efficient stripping of Au(III). However, when the (NH) ₂ S ₂ O ₃ concentration is more than 0.5M, the removal rate of Cu(II) is increased, so that the purity of the removed Au(III) can be lowered. Therefore, it is preferable to maintain the (NH) ₂ S ₂ O ₃ concentration at 0.5 M or less.

Figure 6 shows the change in the stripping rate according to the NH ₄ Cl concentration. At this time, the solution used for the stripping was an extract extracting Au(III), and the concentration of NH ₄ Cl was 0.3 to 1.0M, the O/A ratio was 1, and the stripping time was 30 minutes.

6, Zn(II) was 100% stripped in the NH ₄ Cl concentration range of 0.3 to 1.0M, but in the case of Au(III), 100% stripping was possible from 1.0M or higher. That is, a concentration of 1.0 M or more is preferred for efficient stripping of Au(III). However, when the NH ₄ Cl concentration exceeds 1.0M, the removal rate of Cu(II) is increased, and the purity of the finally removed Au(III) may be lowered. Therefore, it is desirable to maintain the concentration of NH ₄ Cl at 0.5M or less.

According to a preferred embodiment of the present invention, as a result of performing stripping, when performing stripping with 0.5M of (NH) ₂ S ₂ O ₃ , in one stripping step, a high purity Au(III) solution of 99.9% or higher Was able to get

That is, according to the method according to the present invention, Au (III), Ag (I), Cu (II), Ni (II), Zn (II), Sn (II) from the hydrochloric acid leachate containing high purity Au ( III) can be recovered.

Claims (9)

Di-2,4,4-trimethylpentyl phosphinic acid in a hydrochloric acid leachate containing Au(III), Sn(II), Ag(I), Cu(II), Ni(II) and Zn(II) ( Di-2,4,4-trimethylpentyl phosphinic acid) is used as an extraction solvent to extract components containing Au(III) and Sn(II),
(NH ₂ ) ₂ CS, NH ₄ Cl and (NH) ₂ S ₂ O ₃ by using at least one stripping agent selected from, the components containing Au(III) and Sn(II) are extracted di-2, A method for recovering gold from hydrochloric acid leachate, comprising the step of selectively stripping and separating Au(III) from 4,4-trimethylpentyl phosphinic acid (Di-2,4,4-trimethylpentyl phosphinic acid). According to claim 1,
In the leachate, the concentration of hydrochloric acid is 0.5M or more, a method of recovering gold from the leachate of hydrochloric acid. According to claim 1,
In the leachate, the concentration of hydrochloric acid is 3M or more, a method of recovering gold from the leachate of hydrochloric acid. According to claim 1,
The concentration of the di-2,4,4-trimethylpentyl phosphinic acid (Di-2,4,4-trimethylpentyl phosphinic acid) is 0.1M or more, a method of recovering gold from a hydrochloric acid leachate. delete According to claim 1,
The step of selectively extracting Au(III) and Sn(II) consists of two-step countercurrent extraction, a method for recovering gold from a hydrochloric acid leachate. According to claim 1,
The stripping agent is (NH) ₂ S ₂ O ₃ , the concentration is more than 0M ~ 0.5M, gold recovery method from the hydrochloric acid leachate. According to claim 1,
The stripping agent is (NH ₂ ) ₂ CS, its concentration is more than 0M ~ 0.9M, the method of recovering gold from the hydrochloric acid leachate. According to claim 1,
The stripping agent is NH ₄ Cl, the concentration is more than 0M ~ 1.0M, gold recovery method from the hydrochloric acid leachate.

Images