阅读说明：本技术 一种基于电容去离子技术回收溶液中贵金属的方法 (Method for recovering noble metal in solution based on capacitive deionization technology ) 是由 贾菲菲 刘畅 宋少先 陈鹏 梁雨梦 于 2021-07-16 设计创作，主要内容包括：本发明涉及一种基于电容去离子技术回收溶液中贵金属的方法。步骤为：将贵金属络合离子溶液倒入反应槽中,将两个设有活性炭层的电极板,以设有活性炭层的那一面相对,插入到反应槽中,作为阴极、阳极与外接电源相连,在电压为0.8-1.2 V下的条件下进行贵金属的回收。本发明实现了对含有贵金属络合离子溶液中贵金属的高效回收,如Au(S-(2)O-(3))-(2)～(3-)或Au(CN)-(2)～(-)中金的高效回收；此方法使用的电压较低,不会产生析氢反应与金的还原竞争电子,与传统的电沉积工艺相比,极大降低了能耗。(The invention relates to a method for recovering noble metals in a solution based on a capacitive deionization technology. The method comprises the following steps: pouring the noble metal complex ion solution into a reaction tank, inserting two electrode plates with activated carbon layers into the reaction tank by using the surfaces with the activated carbon layers opposite to each other, connecting the electrode plates as a cathode and an anode with an external power supply, and recovering the noble metal under the condition that the voltage is 0.8-1.2V. The invention realizes the high-efficiency recovery of noble metal in the solution containing noble metal complex ions, such as Au (S) 2 O 3 ) 2 3‑ Or Au (CN) 2 ‑ The gold is efficiently recovered; the method has the advantages of low voltage, no generation of hydrogen evolution reaction and competitive electrons of reduction of gold, and greatly reduced energy consumption compared with the conventional electrodeposition process.)

1. A method for recovering noble metals in a solution based on a capacitive deionization technology comprises the following steps: pouring the noble metal complex ion solution into a reaction tank, inserting two electrode plates with activated carbon layers into the reaction tank by using the surfaces with the activated carbon layers as opposite, respectively serving as a cathode and an anode, connecting with an external power supply, and recovering the noble metal under the condition that the voltage is 0.8-1.2V.

2. The method of claim 1, wherein: after recovery, the suspended matter in the solution is filtered to separate out the reduced noble metal particles.

3. The method of claim 1, wherein: the noble metal is Au.

4. The method of claim 1, wherein: the solution is Au (S)₂O₃)₂ ^3-Or Au (CN)₂ ^-。

5. The method of claim 1, wherein: the activated carbon layer contains activated carbon and a conductive material.

6. The method of claim 5, wherein: the preparation method of the electrode plate with the activated carbon layer comprises the following steps:

providing a substrate;

providing a slurry containing activated carbon and conductive carbon black, coating the slurry on one side of a substrate, and drying; then taking out, soaking and removing impurities; and finally taking out and drying to obtain the electrode plate with the activated carbon layer.

Technical Field

The invention relates to a method for recovering noble metals in a solution based on a capacitive deionization technology.

Background

The technical route for extracting noble metals from natural ores successively relates to the processes of leaching, adsorption, desorption, electrodeposition and the like. Noble metals in the ore can be transferred into the leaching liquid by adopting a cyaniding leaching method or a thiosulfate leaching method; precious metals in the leaching solution can be enriched to obtain precious solution through the adsorption and desorption processes; finally, the noble metal complex ions can be converted into elementary substance state through the reduction action of the electrodeposition method, so that the noble metal can be recovered.

In the traditional technology for recovering noble metals by electrodeposition at present, the voltage used in the electrodeposition process is usually above 4V to have a certain recovery effect, and under the voltage, the cathode can also involve hydrogen evolution besides participating in the reduction reaction of the noble metals, so that the current efficiency is low, and the energy is wasted. Therefore, it is desirable to provide a new technical approach to improve the conventional electrodeposition process to achieve efficient recovery of noble metals from solution.

Disclosure of Invention

The invention aims to solve the technical problem of a method for recovering noble metals in a solution based on a capacitive deionization technology.

The method for recovering the noble metal in the solution based on the capacitive deionization technology comprises the following steps: pouring the noble metal complex ion solution into a reaction tank, inserting two electrode plates with activated carbon layers into the reaction tank by using the surfaces with the activated carbon layers as opposite, respectively serving as a cathode and an anode, connecting with an external power supply, and recovering the noble metal under the condition that the voltage is 0.8-1.2V.

According to the scheme, after the recovery is finished, the suspended matters in the solution are filtered, and the reduced noble metal particles are separated, so that the aim of recovering the noble metals is fulfilled.

According to the scheme, the noble metal is Au, and the solution is Au (S)₂O₃)₂ ^3-Or Au (CN)₂ ^-。

According to the scheme, the activated carbon layer contains activated carbon and conductive materials, and the preparation method of the electrode plate with the activated carbon layer comprises the following steps:

providing a substrate;

providing a slurry containing activated carbon and conductive carbon black, coating the slurry on one side of a substrate, and drying; then taking out, soaking and removing impurities; and finally taking out and drying to obtain the electrode plate with the activated carbon layer.

The preparation method comprises the following steps: respectively mixing and grinding activated carbon, conductive carbon black and a PVDF-containing N, N-dimethylacetamide solution into paste, and then coating the paste on a substrate and drying the paste to prepare an activated carbon electrode;

the invention adopts the electrode plate with the activated carbon layer as the cathode and the anode, treats the solution containing the noble metal complex ions under the condition of 0.8-1.2V of voltage and based on the capacitive deionization technology, and can realize the recovery of the noble metal in the solution under lower voltage.

The invention has the beneficial effects that:

1. the invention can replace the adsorption, desorption and electrodeposition processes in the traditional hydrometallurgy technology by the capacitive deionization technology, simplifies the process flow and can realize the reduction and recovery of gold in the leaching solution by one step;

2. the invention realizes the recovery of noble metal, such as Au (S), in the solution containing noble metal complex ions₂O₃)₂ ^3-Or Au (CN)₂ ^-Effectively recovering gold in the solution;

3. the voltage used in the technology is lower, the hydrogen evolution reaction and the reduction competition electrons of gold can not be generated, and compared with the traditional electrodeposition technology, the energy consumption is greatly reduced.

Drawings

Fig. 1 shows an activated carbon-coated electrode material (the black part is activated carbon and the substrate is a titanium plate).

FIG. 2 shows the recovery of Au (S) by capacitive deionization₂O₃)₂ ^3-The apparatus of (1).

FIG. 3 shows the capacitive deionization technique for Au (S) under different voltages in example 1₂O₃)₂ ^3-Recovery rate is related to reaction time.

FIG. 4 shows the comparison of comparative example 1 with Au (S) by electrodeposition technique at different voltages₂O₃)₂ ^3-Recovery rate is related to reaction time.

FIG. 5 shows the capacitive deionization technique of example 2 for Au (CN)₂ ^-Recovery rate is related to reaction time.

FIG. 6 shows the comparative example 2 electrodeposition technology for recovery of Au (CN)₂ ^-The test results of (1).

Detailed Description

Example 1

(1) Preparing an activated carbon electrode: mixing 80mg of activated carbon, 10mg of conductive carbon black and an N, N-dimethylacetamide solution containing 10mg of PVDF, grinding for 10 minutes to form a paste, and then coating the paste on a titanium plate and drying to prepare an activated carbon electrode;

(2) active carbon electrode pair Au (S)₂O₃)₂ ^3-Capacitive deionization recovery test of (1): with HAuCl₄、(NH₄)₂S₂O₃And Na₂S₂O₃200ml of Au (S) was prepared₂O₃)₂ ^3-Solution (gold concentration 25mg/L, with excess S₂O₃ ^2-4mmol/L) and pouring the mixture into a reaction tank; the activated carbon electrode is inserted into the solution with the surface provided with the activated carbon layer opposite to the surface, and the activated carbon electrode is respectively connected with a power supply as a cathode and an anode through leads; reacting at 0.8V and 1.2V, in the course of which the solution inside is circulated by the action of a peristaltic pump; in the reaction process, gold particles can be separated out from the cathode plate; after 22 hours, gold particles can be separated from the solution by simple filtration membrane filtration, so that the recovery effect is achieved; the higher the voltage, the better the gold recovery effect; under the voltage condition of 1.2V, the recovery rate of gold reaches 90 percent (as shown in figure 3).

Preparation of a thiosulfate solution of the noble metal: preparing a thiosulfate solution of the noble metal by adopting a gold solution and a thiosulfate solution under the system pH alkaline condition, which specifically comprises the following steps: taking HAuCl₄、(NH₄)₂S₂O₃And Na₂S₂O₃Adjusting the pH of the system to 10 to prepare the product containing excess S₂O₃ ^2-Au (S) of₂O₃)₂ ^3-200ml of solution (gold concentration 25mg/L, with excess S₂O₃ ^2-4mmol/L)。

Comparative example 1

Electrodeposition of Au (S)₂O₃)₂ ^3-Recovery test of (2): with HAuCl₄、(NH₄)₂S₂O₃And Na₂S₂O₃200ml of Au (S) was prepared₂O₃)₂ ^3-Solution (gold concentration 25mg/L, with excess S₂O₃ ^2-4mmol/L) and pouring the mixture into a reaction tank; inserting a titanium plate into the solution and respectively connecting a power supply by using leads as a cathode and an anode; electrodeposition was performed at voltages of 1.2V, 2.5V and 4.0V to recover Au (S)₂O₃)₂ ^3-The test of (1); as can be seen from the test results shown in fig. 4, the gold was not recovered at a voltage of 1.2V. The recovery rate of gold after 22 hours at 2.5V and 4.0V was only 10% and 56%, i.e. electrodeposition recovery at higher voltage was inferior to that of the activated carbon capacitive deionization at low voltage.

Example 2

(1) Preparing an activated carbon electrode: mixing 80mg of activated carbon, 10mg of conductive carbon black and an N, N-dimethylacetamide solution containing 10mg of PVDF, grinding for 10 minutes to form a paste, and then coating the paste on a titanium plate and drying to prepare an activated carbon electrode;

(2) active carbon electrode pair Au (CN)₂ ^-Capacitive deionization recovery test of (1): taking Au (CN) from a certain gold mine factory₂ ^-Pouring 200mL of the solution into a reaction tank; the activated carbon electrode is inserted into the solution by opposite to the surface provided with the activated carbon layer, and is respectively connected with a power supply by leads to be used as a cathode and an anode; recovery of Au (CN) by capacitive deionization of activated carbon at 1.2V₂ ^-The test of (1); as can be seen from the test results shown in fig. 5, the recovery rate of gold reached 95% after 23 hours at a voltage of 1.2V.

Comparative example 2

Electrodeposition method for Au (CN)₂ ^-Recovery test of (2): taking Au (CN) from a certain gold mine factory₂ ^-Pouring 200mL of the solution into a reaction tank; inserting a titanium plate into the solution and respectively connecting a power supply with a lead as a cathode and an anode;electrodeposition at 1.2V and 4.8V for recovery of Au (CN)₂ ^-The test of (1); as can be seen from the test results shown in FIG. 6, the recovery rate of gold after 22 hours at 1.2V was only 10%, and the recovery rate was determined for Au (CN)₂ ^-The recovery effect of (A) is far inferior to that of the activated carbon capacitive deionization method of the embodiment. The recovery rate of gold after 23 hours at 4.8V was 95%, which was substantially the same as the effect of the capacitive deionization of activated carbon in example 2 at a low voltage.