阅读说明：本技术 离子液体电解精炼粗铅的方法以及回收金属铋和银的方法 (Method for electrorefining lead bullion by using ionic liquid and method for recovering metal bismuth and silver ) 是由 徐存英 黄梦婷 华一新 张启波 汝娟坚 李艳 李坚 于 2019-09-29 设计创作，主要内容包括：本发明提供了一种离子液体电解精炼粗铅的方法以及回收金属铋和银的方法,精炼方法可以包括：将离子液体与可溶性铅盐混合,搅拌后形成电解液,其中,可溶性铅盐浓度为0.05mol/L～0.2mol/L；以粗铅为阳极,在所述电解液中,控制电解温度为30℃～70℃,直流电流密度为10A/m<Sup>2</Sup>～100A/m<Sup>2</Sup>的条件下进行电解,完成粗铅精炼。所述回收方法可以包括利用上述精炼方法对粗铅中的锡和锑去除并对金属铋和银进行回收。本发明的精炼方法能够避免火法精炼金属直收率低、渣量大等缺陷,同时能够避免硅氟酸电解后污染环境的问题,环境友好；回收方法能够很好的除去粗铅中的金属锡和锑,能够较易的从粗铅中回收得到金属铋和银。(The invention provides a method for electrorefining lead bullion by ionic liquid and a method for recovering metal bismuth and silver, wherein the refining method comprises the following steps: mixing the ionic liquid with soluble lead salt, and stirring to form electrolyte, wherein the concentration of the soluble lead salt is 0.05-0.2 mol/L; taking crude lead as an anode, controlling the electrolysis temperature to be 30-70 ℃ and the direct current density to be 10A/m in the electrolyte 2 ～100A/m 2 And (4) carrying out electrolysis under the condition of (1) to finish refining the crude lead. The recovery process may include stripping tin and antimony from the lead bullion using the refining process described aboveRemoving and recovering the metal bismuth and silver. The refining method disclosed by the invention can avoid the defects of low direct recovery rate, large slag amount and the like of fire refining metal, can avoid the problem of environmental pollution after silicofluoric acid electrolysis, and is environment-friendly; the recovery method can well remove the metal tin and antimony in the crude lead and can easily recover and obtain the metal bismuth and silver from the crude lead.)

1. A method for electrorefining lead bullion with ionic liquid, characterized in that the method comprises the following steps:

mixing the ionic liquid with soluble lead salt, and stirring to form electrolyte, wherein the concentration of the soluble lead salt is 0.05-0.2 mol/L;

taking crude lead as an anode, controlling the electrolysis temperature to be 30-70 ℃ and the direct current density to be 10A/m in the electrolyte²～100A/m²And (4) carrying out electrolysis under the condition of (1) to finish refining the crude lead.

2. The method for electrolytic refining of lead bullion according to claim 1, wherein the ionic liquid is one or more of 1-butyl-3-methylimidazole dicyanamide salt, 1-butyl-3-methylimidazole thiocyanate, choline chloride-tartaric acid and acetamide-ethylene glycol.

3. The method for electrolytic refining of lead bullion by using an ionic liquid according to claim 1, wherein the lead bullion comprises 80 to 99% of lead, more than 0.1% of antimony, 0 to 3.0% of copper, 0 to 1.5% of arsenic, 0 to 3.0% of tin, 0.1 to 1% of bismuth and 0 to 3.0% of silver by mass percentage.

4. The method for electrolytic refining of lead bullion by using an ionic liquid according to claim 1 or 3, wherein the lead bullion comprises 80 to 90% by mass of lead and 14% or more by mass of antimony.

5. A method for electrolytic refining of lead bullion according to claim 1, characterized in that the soluble lead salt is lead nitrate or lead thiocyanate.

6. The method for electrolytic refining of lead bullion by using an ionic liquid as claimed in claim 1, wherein the lead obtained after completion of the lead bullion refining has a purity of 99.9%.

7. A method for removing tin and antimony from crude lead and recovering metal bismuth and silver is characterized by comprising the following steps:

mixing the ionic liquid with soluble lead salt, and stirring to form electrolyte, wherein the concentration of the soluble lead salt is 0.05-0.2 mol/L;

taking crude lead as an anode, controlling the electrolysis temperature to be 30-70 ℃ and the direct current density to be 10A/m in the electrolyte²～100A/m²The electrolysis is carried out under the conditions of (1) removing metallic tin and antimony from the lead bullion and recovering metallic bismuth and silver from the anode slime.

8. The method for removing tin and antimony from crude lead and recovering bismuth and silver according to claim 7, wherein the crude lead contains more than 0.3% of metallic tin and more than 1% of antimony by mass percent.

9. The method for removing tin and antimony from crude lead and recovering bismuth and silver according to claim 7, wherein the ionic liquid is one or more of 1-butyl-3-methylimidazole dicyanamide salt, 1-butyl-3-methylimidazole thiocyanate, choline chloride-tartaric acid and acetamide-ethylene glycol.

10. The method for removing tin and antimony from lead bullion and recovering bismuth and silver as claimed in claim 7, wherein the soluble lead salt is lead nitrate or lead thiocyanate.

Technical Field

The invention belongs to the technical field of nonferrous metallurgy, and particularly relates to a method for electrorefining lead bullion by using an ionic liquid and a method for recovering bismuth and silver.

Background

In the prior art, lead bullion produced by various methods contains a certain amount of impurities, and in order to remove harmful impurities and recover valuable elements such as noble metals in the lead bullion, the lead bullion needs to be refined, and the refining method is divided into fire refining and electrolytic refining. The fire refining process of lead is multiple, a large amount of lead (and other metal) smoke and various intermediate slag and sulfur dioxide gas are generated, the environmental pollution is serious, the labor environment is poor, and the lead yield and the comprehensive recovery rate of valuable elements such as noble metals are low.

At present, the electrolytic refining of lead bullion adopts a solution system consisting of silicofluoric acid and lead silicofluoride as electrolyte for electrolysis, and the main defects of the electrolysis in the system are as follows: (1) silicofluoric acid is volatile and decomposes into toxic HF and SiF₄A large amount of acid mist is formed on a working site due to gas, the smell is unpleasant, and the harm to human bodies and the environment is very large; (2) widely used 105-200A/m²Under the current density, the direct current power consumption of each ton of lead is 110-190 kw.h, and the energy consumption is high; (3) the current efficiency is low, only about 90%; (4) the lead content in the lead bullion anode is generally between 95 percent and 99 percent, and the requirement on the content of impurity metal antimony is strict,the content of antimony in the lead bullion anode is less than 0.3%, and the anode mud is easy to break and fall off, so that the loss of precious metals is serious, and the chemical components of the cathode lead are unqualified; when the content of antimony in the crude lead exceeds 3%, the anode mud is extremely hard and cannot be brushed off, and meanwhile, the concentration of lead ions in the electrolyte is reduced, so that the electrolysis is difficult to normally carry out.

Disclosure of Invention

In view of the deficiencies in the prior art, it is an object of the present invention to address one or more of the problems in the prior art as set forth above. For example, it is an object of the present invention to provide a method for refining lead bullion with low energy consumption, high current efficiency, and environmental friendliness.

In order to achieve the above object, an aspect of the present invention provides a method for ionic liquid electrorefining of lead bullion, which may include the steps of: mixing the ionic liquid and soluble lead salt, and stirring to form electrolyte, wherein the concentration of the soluble lead salt is 0.05-0.2 mol/L; taking crude lead as an anode, controlling the electrolysis temperature to be 30-70 ℃ and the direct current density to be 10A/m in the electrolyte²～100A/m²And (4) carrying out electrolysis under the condition of (1) to finish refining the crude lead.

In one exemplary embodiment of the method for electrolytic refining of lead bullion by using the ionic liquid of the present invention, the ionic liquid may be one or more of 1-butyl-3-methylimidazole dicyanamide salt, 1-butyl-3-methylimidazole thiocyanate, choline chloride-tartaric acid and acetamide-ethylene glycol.

In an exemplary embodiment of the method for electrolytic refining of lead bullion by using the ionic liquid of the present invention, the lead bullion may include 80% to 99% of lead, more than 0.1% of antimony, 0% to 3.0% of copper, 0% to 1.5% of arsenic, 0% to 3.0% of tin, 0.1% to 1% of bismuth, and 0% to 3.0% of silver by mass percentage.

In one exemplary embodiment of the method for electrolytic refining of lead bullion by using the ionic liquid of the present invention, the lead bullion comprises 80 to 90% of lead and 14% or more of antimony by mass percent.

In one exemplary embodiment of the method for electrolytic refining of lead bullion with an ionic liquid of the present invention, the soluble lead salt may be lead nitrate or lead thiocyanate.

In one exemplary embodiment of the method for electrolytic refining of lead bullion with an ionic liquid of the present invention, the concentration of the soluble lead salt may be in the range of 0.08mol/L to 0.17 mol/L.

In one exemplary embodiment of the method for electrolytic refining of lead bullion by using the ionic liquid, the electrolysis temperature can be 40-70 ℃, and the direct current density can be 30A/m²～100A/m²。

In an exemplary embodiment of the method for electrolytic refining of lead bullion according to the present invention, the purity of the lead obtained after completion of the lead bullion refining may be 99.9%.

In one exemplary embodiment of the method for electrolytic refining of lead bullion by using an ionic liquid of the present invention, the method further comprises using a pure lead sheet or stainless steel as a cathode.

In another aspect of the present invention, a method for removing tin and antimony from lead bullion and recovering metal bismuth and silver is provided, which may include: mixing the ionic liquid with soluble lead salt, and stirring to form electrolyte, wherein the concentration of the soluble lead salt is 0.05-0.2 mol/L; taking crude lead as an anode, controlling the electrolysis temperature to be 30-70 ℃ and the direct current density to be 10A/m in the electrolyte²～100A/m²The electrolysis is carried out under the conditions of (1) removing metallic tin from the lead bullion and recovering metallic bismuth and silver from the anode slime.

In an exemplary embodiment of the method for removing tin and antimony and recovering bismuth and silver from crude lead, the content of metal tin in the crude lead is more than 0.3%, and the content of metal antimony in the crude lead is more than 1%.

In an exemplary embodiment of the method for removing tin and antimony from crude lead and recovering metal bismuth and silver, the ionic liquid is one or more of 1-butyl-3-methylimidazole dicyanamide salt, 1-butyl-3-methylimidazole thiocyanate, choline chloride-tartaric acid and acetamide-ethylene glycol.

In an exemplary embodiment of the method for removing tin and antimony from crude lead and recovering metal bismuth and silver, the soluble lead salt is lead nitrate or lead thiocyanate.

Compared with the prior art, the invention has the beneficial effects that:

(1) the refining method disclosed by the invention can avoid the defects of low direct recovery rate, large slag amount and the like of fire refining metal, can avoid the problem of environmental pollution after silicofluoric acid electrolysis, and is environment-friendly;

(2) the refining method has the advantages of low energy consumption, high electrolysis efficiency and high purity of the refined product;

(3) the detinning recovery method of the invention can well remove the metallic tin in the crude lead and can easily recover the metallic bismuth and silver in the anode mud.

Drawings

The above and other objects and features of the present invention will become more apparent from the following description taken in conjunction with the accompanying drawings, in which:

FIG. 1 shows a simplified schematic flow diagram of a method for electrorefining lead bullion with ionic liquid according to an exemplary embodiment of the invention;

figure 2 shows the XRD pattern of cathode lead obtained in example 1 of the present invention;

FIG. 3 shows a scanning electron micrograph of cathodic lead obtained in example 1 of the present invention.

Detailed Description

Hereinafter, a method for electrorefining lead bullion by an ionic liquid and a method for recovering metallic bismuth and silver according to the present invention will be described in detail with reference to the accompanying drawings and exemplary embodiments.

One aspect of the invention provides a method for electrorefining lead bullion by using ionic liquid. In one exemplary embodiment of the ionic liquid electrolytic refining lead bullion method of the present invention, as shown in fig. 1, the method may comprise:

and S01, mixing the ionic liquid with soluble lead salt, and stirring to form electrolyte.

S02, taking the crude lead as an anode, controlling the electrolysis temperature to be 30-70 ℃ and the direct current density to be 10A/m in the electrolyte²～100A/m²And (4) carrying out electrolysis under the condition of (1) to finish refining the crude lead. The electrolysis temperature can be set to ensure that electrolysis can be carried out within the temperature rangeThe liquid has stable performance and good conductivity. If the electrolysis temperature is lower than 30 ℃, the conductivity of the electrolyte is not good; if the electrolysis temperature is higher than 70 ℃, the long-term operation of the electrode solution becomes unstable, for example, the electrolyte solution acetamide-ethylene glycol is unstable in performance at a temperature higher than 70 ℃, which may cause decomposition of the electrolyte solution. At 10A/m²～100A/m²The purity of the obtained cathode lead is higher and can reach more than 99.9 percent under the current density. If the current density is too low, the rate of electrolysis is too slow; if the current density is too high, the purity of the cathode lead may be reduced.

In this embodiment, the soluble lead salt may be a lead salt that can be dissolved in an ionic liquid. For example, the soluble lead salt may be lead nitrate or lead thiocyanate. Of course, the soluble lead salt of the present invention is not limited thereto, and may be, for example, lead acetate.

In this embodiment, the concentration of the soluble lead salt in the electrolyte may be 0.05mol/L to 0.2 mol/L. Further, the concentration may be 0.08mol/L to 0.17 mol/L. Further, the concentration may be 0.12 mol/L. In the electrolytic process, if the concentration of soluble lead salt is lower than 0.05mol/L, the conductivity of the solution is poor, and the cathode polarization potential is large. When the concentration of the lead salt is between 0.05mol/L and 0.2mol/L, the conductivity of the electrolyte is good. If the concentration exceeds 0.2mol/L, the conductivity of the electrolyte is lowered, which is disadvantageous in terms of the electrolysis efficiency.

In this embodiment, the ionic liquid may be one or more of 1-butyl-3-methylimidazole dicyanamide salt, 1-butyl-3-methylimidazole thiocyanate, choline chloride-tartaric acid, and acetamide-ethylene glycol. The ionic liquid used in the invention needs to ensure good dissolving performance for lead salt and ensure that the anode dissolving potential of lead and antimony is greatly different. Therefore, the above ionic liquid is selected as the electrolytic solution of the present invention.

In this embodiment, the crude lead may include 80% to 99% and more than 0.1% of antimony by mass. For example, the crude lead can also comprise 0 to 3.0 percent of copper, 0 to 1.5 percent of arsenic, 0 to 3.0 percent of tin, 0.1 to 1 percent of bismuth and 0 to 3.0 percent of silver. For example, 2.5% copper, 1.2% arsenic, 2.1% tin, 0.9% bismuth, and 1.8% silver may be included. Of course, there is no requirement for the impurity content of the lead bullion using the electrolytic refining process of the present invention. Further, the lead bullion can comprise 80 to 94 percent of lead and more than 0.5 percent of antimony by mass percent.

In the traditional silicofluoric acid electrolytic refining method for the crude lead, the impurity content needs to be strictly controlled, the lead content is generally 95-99%, the antimony content needs to be controlled at 0.3-1.0%, the bismuth content and the copper content cannot be too much, otherwise, anode mud is hard and compact, and electrolytic refining cannot be carried out. The method for refining the crude lead by electrolysis has no requirement on the content of impurities, the electrolysis is not influenced when the content of antimony is up to 20%, and the anode mud is not hardened, so that the method can be used for directly treating the crude lead (the content of antimony is up to 14%) obtained by smelting the jamesonite. Because the impurity content of copper and bismuth is not required, the lead bismuth alloy can be obtained by electrolytic refining. In the traditional silicofluoric acid electrolysis, the potential of lead and tin is close, and tin in the crude lead cannot be removed by an electrolytic refining method, while in the ionic liquid electrolyte used in the invention, the oxidation potentials of lead and tin are obviously different, and the tin in the crude lead can be removed by the electrolytic refining method. After the electrolytic refining is finished, the valuable metals of bismuth and silver in the anode mud are easily separated and extracted from the anode mud.

In this embodiment, the electrolysis temperature may be 40-70 deg.C, and the DC current density may be 30A/m²～100A/m². Further, the electrolysis temperature may be 60 ℃ and the direct current density may be 65A/m²。

In this example, the purity of the lead obtained after the electrolytic refining was completed was 99.9% or more. For example, it can be 99.95% or more.

In this embodiment, the method may also use pure lead or stainless steel as the cathode.

The invention also provides a method for removing tin and antimony from the crude lead and recovering metal bismuth and silver. An exemplary embodiment of the method for removing tin and antimony from crude lead and recovering metal bismuth and silverIn an embodiment, the method may comprise: mixing the ionic liquid with soluble lead salt, and stirring to form electrolyte, wherein the concentration of the soluble lead salt is 0.05-0.2 mol/L; taking crude lead as an anode, controlling the electrolysis temperature to be 30-70 ℃ and the direct current density to be 10A/m in the electrolyte²～100A/m²The electrolysis is carried out under the conditions of (1) removing metallic tin and antimony from the lead bullion and recovering metallic bismuth and silver from the anode slime.

In this embodiment, the content of the metallic tin in the lead bullion may be 0.3% or more, for example, the content may be 1.2%. The content of the metallic antimony is 1% or more, for example, 15% or more. In conventional lead bullion refining methods, the content of metallic tin and metallic antimony must be strictly controlled in lead bullion refining. Too high or too low of metallic tin and antimony may affect the chemical composition of the cathode lead, resulting in a stiff anode slime making electrolysis difficult. The method of the invention has almost no upper limit requirement on the contents of tin and antimony in the crude lead, and can carry out electrolytic refining on tin and antimony with larger contents. In addition, the invention is easy to recover the metal bismuth and silver. The metal bismuth and silver can well enter the anode mud, and the recovery rate is high.

The use of the materials, parameter settings, and the like in the steps of the method for removing tin and antimony from lead bullion and recovering bismuth and silver metals are the same as those in the method for electrolytic refining of lead bullion by using the ionic liquid.

In order that the above-described exemplary embodiments of the invention may be better understood, further description thereof with reference to specific examples is provided below.

Example 1

(1) Mixing 1-butyl-3-methylimidazole dicyandiamide salt with lead nitrate, and stirring to form an electrolyte, wherein the concentration of the lead nitrate is 0.06 mol/L;

(2) the lead-free electrolytic solution comprises, by mass, 82% of lead, 13% of antimony, 2.0% of copper, 1.2% of arsenic, 1.6% of tin, 0.5% of bismuth and 2.1% of silver lead bullion as an anode, and in the electrolyte, the electrolytic temperature is controlled to be 60 ℃, and the direct current density is 50A/m²The electrolysis is carried out under the condition of (1) to finish the refining of the crude lead, and the metallic lead with the purity of 99.92 percent is obtained.The XRD of metallic lead is shown in fig. 2. The content of impurities in the metallic lead is low. The scanning electron micrograph of the metallic lead is shown in FIG. 3, and the cathode lead is granular.

Example 2

(1) Mixing acetamide-ethylene glycol and lead thiocyanate, and stirring to form electrolyte, wherein the concentration of the lead thiocyanate is 0.1 mol/L;

(2) the lead-free electrolytic solution comprises 87 mass percent of lead, 21 mass percent of antimony, 2.0 mass percent of copper, 1.2 mass percent of arsenic, 1.6 mass percent of tin, 0.5 mass percent of bismuth and 1.8 mass percent of silver lead bullion as anodes, and in the electrolytic solution, the electrolytic temperature is controlled to be 32 ℃, and the direct current density is 20A/m²The electrolysis is carried out under the condition of (1) to finish the refining of the crude lead, and the metallic lead with the purity of 99.98 percent is obtained.

Example 3

(1) Mixing acetamide-ethylene glycol and lead thiocyanate, and stirring to form electrolyte, wherein the concentration of the lead thiocyanate is 0.2 mol/L;

(2) the lead-free electrolytic solution comprises 87 mass percent of lead, 0.8 mass percent of antimony, 2.0 mass percent of copper, 1.2 mass percent of arsenic, 1.6 mass percent of tin, 0.5 mass percent of bismuth and 1.8 mass percent of silver lead bullion serving as an anode, and in the electrolytic solution, the electrolytic temperature is controlled to be 50 ℃, and the direct current density is 80A/m²The electrolysis is carried out under the condition of (1) to finish the refining of the crude lead, and the metallic lead with the purity of 99.97 percent is obtained.

In conclusion, the refining method provided by the invention avoids the defects of low direct recovery rate, large slag quantity and the like of fire refining metal, and simultaneously solves the problem of environmental pollution caused by silicofluoric acid electrolysis; the refining method of the invention has low energy consumption, high electrolysis efficiency and high purity of the refined product. The detinning recovery method of the invention can well remove the metallic tin in the crude lead and can easily recover the metallic bismuth and silver in the anode mud.

Although the present invention has been described above in connection with exemplary embodiments, it will be apparent to those skilled in the art that various modifications and changes may be made to the exemplary embodiments of the present invention without departing from the spirit and scope of the invention as defined in the appended claims.