KR20060104091A - Electrogenerated chloride leaching and its apparatus - Google Patents

Abstract

The present invention relates to a leaching of valuable metals by electrochemically generated chlorine and an electrolytic leaching apparatus therefor, and more particularly, an electrolytic leaching apparatus comprising: left and right reaction chambers divided into a central separator; One of the reaction chambers is composed of a leaching reaction chamber equipped with a stable electrode for chlorine leaching for electrochemical chlorine generation and a stirrer for stirring the solution, the other is an electrode for electrolytic recovery of some or all of the leached valuable metal components It consists of a reduction reaction chamber installed, and relates to leaching by electrolytically generated chlorine using this. This is to provide a very simple leaching method and an electrolytic leaching device while being very efficient at leaching and recovering valuable metal components leached at the same time.

Electrolytic Method, Chlorine, Electroleaching Device

Description

Leaching Using Electrolyzed Chlorine and Electrolytic Leaching Apparatus

1 is a schematic diagram of an electroleaching apparatus of the present invention.

2 is a cross-sectional view of the electroleaching apparatus of the present invention.

Explanation of symbols on main parts of drawing

1 Leaching Reaction Chamber 2 Recovery Reaction Chamber

3 separator 4 cover

5 anode 6 cathode

7 Stirring Rod 8 Stirring Motor

The present invention relates to leaching of valuable metals by chlorine produced electrochemically and to an electrolytic leaching apparatus therefor.

In general, noble metals or poorly soluble metals having high redox potential are leached by reacting high concentrations of oxidizing acid at high temperatures. In this case, due to the constant consumption of acid, a large amount of acid is required, and the treatment of waste liquid generated therein can cause environmental problems. In addition, a separate recovery device is required to recover the leached valuable metals, and separate energy is consumed for this purpose.

In addition, the conventional chlorine leaching method is to inject chlorine gas stored in the high-pressure gas container into the reaction vessel to leach, so the gaseous chlorine must be handled outside the leaching container, which may cause a complicated device and cause a safety problem. In addition, after the leaching is completed, it is necessary to go through a recovery step of a separate leaching metal is the same as the general acid leaching. Therefore, in order to effectively recycle precious metals or poorly soluble metals having high redox potential, it is necessary to develop new methods and devices for safe and low-environmentally friendly leaching and recovery.

The present invention is simple to install a very low concentration of acid compared to the conventional leaching method, and the leaching method by electrolytically produced chlorine with high energy efficiency as it is possible to recover valuable metals simultaneously with leaching It is to provide an electrolytic leaching device for.

In another aspect, the present invention is to provide a method for leaching precious metals and poorly soluble metals and recovering leached valuable metals using the electrolytic leaching apparatus of the present invention.

The present invention relates to a leaching using an electrolytically produced chlorine which can be very efficiently applied to leaching the metal from solid materials containing precious metals or other valuable metals, which are difficult to leach by a conventional chemical leaching method, and an electrolytic leaching device therefor. , Electrolytic generation of chlorine which oxidizes chlorine ions contained in the solution at the anode, leaching reaction of reacting electrolytically generated chlorine with the leaching material, and recovery of leached valuable metals occurring at the cathode A leaching method and an electrolytic leaching apparatus for realizing the same.

In particular, the electrolytic production of chlorine and the leaching reaction using the same is characterized in that proceeds simultaneously in the same reactor.

That is, the present invention relates to a method of leaching using chlorine generated electrolytically from an anode in a leachate containing chlorine ions, and a configuration of an electrolytic leaching apparatus for recovering valuable metals leached from a cathode while leaching.

In the leaching method of the electrolytically produced chlorine according to the present invention, since chlorine having a very strong oxidizing power is directly produced in the reaction solution at a relatively low temperature, a leaching reaction is possible only if a low concentration of chlorine ion source is used. Since there is no consumption of chlorine in the solution, it has the advantage that no excess chlorine supply for leaching is required. In addition, the electrolytic recovery of leached valuable metals is possible at the same time as a large reaction of electrolysis of chlorine, which is very efficient in terms of energy. In particular, since chlorine is generated and consumed only in the reactor, which can cause problems when leaking, it is a leaching method that requires only a very safe and simple facility compared to the existing chlorine leaching method.

Salts or acids may be further used for the leaching solution of the present invention. Salts are added for the purpose of imparting ionic conductivity of the electrolyte, and the usable salts include various salts such as sulfates and nitrates, in addition to those containing chlorine ions such as ammonium chloride (NH ₄ Cl), potassium chloride (KCl) and sodium chloride (NaCl). Kind is available. In addition, the acid component is not particularly limited as long as it can increase the ionic conductivity as a common compound such as an organic acid or an inorganic acid.

When an oxidation current is applied to the anode in the leachate containing chlorine ions of the present invention, the chlorine generation reaction occurs by the following equation (1).

_{^{2Cl - → Cl 2 + 2e -}} (1)

Chlorine produced in the anode is spread through the leaching solution through efficient stirring, and valuable metals of solid components present in the leaching solution are leached by the reactions as shown in the following formulas (2) and (3). At this time, the chlorine leaching the metal (M) back to the chlorine ion can be prevented to minimize the consumption of chlorine in the leachate and no additional chlorine supply.

_{(n / 2) Cl 2 +} ne - → nCl - (2)

^{M → M n + + ne -} (3)

At this time, the overall reaction formula is as (4).

M + (n / 2) Cl 2 → M n + + nCl - (4)

Metals that can be leached through this reaction are possible when the redox potential is lower than the redox potential of chlorine. When the voltage is increased when the oxidation current is applied, oxychromide may be formed. It also has an oxidizing power and can be used for leaching reactions.

Hereinafter, the electrolytic leaching apparatus will be described in more detail with reference to the accompanying drawings.

1 is a schematic view showing an electrolytic leaching apparatus according to the present invention, Figure 2 is a cross-sectional view showing an electrolytic leaching apparatus according to the present invention, when it is described, the leaching reaction chamber (1) separated by a separator 3 formed in the center (1) ) And leaching metal recovery reaction chamber (2); A cover 4 of the leaching reaction chamber; A stirring rod 7 and a stirring motor 8, which are electrolyte stirring apparatuses in a leaching reaction chamber; An electrolytic leaching apparatus comprising an anode (5) for producing electrochlorine in a leaching reaction chamber and a reducing electrode (6) for a leaching metal recovery reaction chamber.

The separator 3 is made of a simple membrane or ion exchange membrane, or a combination thereof, such as a filter cloth or a nonwoven fabric, through which leached metal ions can pass, but leachate, electrolytically generated chlorine, and the like cannot pass. The leaching reaction chamber (1) and the recovery reaction chamber (2) are both made of a material that is corrosion resistant to the oxidation of chlorine, and the shape of the container can be variously modified. The lid 4 of the leaching reaction chamber prevents external leakage of electrolytically generated chlorine to seal the leaching reaction chamber and also supports the stirring rod 7 and the anode 5. Stirring rod 7 has an important role to increase the efficiency of the leaching reaction by the effective generation of chlorine into the electrolytic solution, the stirring blade can be variously designed so that this effect is the maximum. The anode 5 plays a role in electrolytic generation of chlorine when an oxidation current is applied, and may be manufactured in various forms of graphite or other conductive material that is physicochemically stable even during electrolysis of chlorine. The stirring rod 7 and the anode 5 can be designed in various shapes and positions. The stirring motor 8 may be fixed or separated on the cover 4 of the leaching reaction chamber.

The reduction electrode 6 of the leaching metal recovery reaction chamber is an electrode in which leached metal ions are recovered by electrolytic reduction, and can be made of most conductive materials stable to an electrolyte solution containing chlorine ions. It is convenient to produce with.

Referring to the operation principle of the electrolytic leaching method and the electroleaching device according to the present invention, the present invention electrolytic leaching device is stable to the leachate containing the electrolytic chlorine can be produced from a variety of materials having a mechanical strength sufficient to maintain the function of the device In this case, chlorine ions contained in the leachate are reduced to chlorine by the oxidation current applied to the anode 5 during electrolytic leaching, and chlorine produced by electrolysis by solution stirring of the stirring rod 7 is effectively contained in the leachate. Reacts with metal ions in water and dissolves in metal ions. In the above dissolution reaction, chlorine is reduced back to chlorine ions so that the consumption of chlorine ions in the leachate does not occur. The amount of chlorine generated per unit time is determined by the amount of oxidation current and the electrode area of the anode, which is directly related to the amount of leaching. Meanwhile, the leached metal is present in the leaching liquid as metal ions, passes through the separation membrane 3, moves to the reduction reaction chamber, and is then electroprecipitated as metal in the reduction electrode to which a reduction current is applied. The electroprecipitation reaction is changed to a hydrogen generation reaction when an anion exchange membrane is used as a material of the separator.

In addition, the control of the electrolyte during electrolytic leaching can be controlled using a separate solution heating device.

An embodiment using the electrolytic leaching apparatus according to the present invention is as follows.

Example 1

Electrolytically produced chlorine leaching was carried out using 400 mL of 1M HCl solution using waste electronic equipment scrap containing about 45.7% of the metal leachate and Cu as the main metal constituent. At this time, the average particle size of the crushed scrap used was between 0.6mm ~ 1.2mm was used 10g in the leaching experiment. The anode was made of graphite having a surface area of 50 cm ² , and the cathode was made of titanium. The applied current was 20 mA / cm ² , agitation speed 400 rpm, and a solution temperature of 50 ° C. After 180 minutes, the metal leaching rate was 97.4%.

Example 2

Electrolytically produced chlorine leaching was carried out using 400 mL of 1M HCl solution using waste electronic equipment scrap containing about 45.7% of the metal leachate and Cu as the main metal constituent. In this case, the average particle size of the crushed scrap used was between 0.6mm and 1.2mm and 10g was used in the leaching test. The anode was made of graphite of 50 cm ² and the cathode was made of titanium. It was conditions of applied voltage 4V, stirring speed 400rpm, and solution temperature of 50 degreeC. After 180 minutes, the metal leaching rate was 95.2%.

Example 3

Electrolytically produced chlorine leaching was carried out using 400 mL of 0.5M HCl solution using waste electronic equipment scrap containing about 45.7% of the metal leachate and Cu as the main metal constituent. At this time, the average particle size of the crushed scrap used was between 0.6mm ~ 1.2mm was used 10g in the leaching experiment. The anode was made of graphite of 50 cm ² and the cathode was made of titanium. The applied current was 10 mA / cm ² , agitation speed 800 rpm, and a solution temperature of 50 ° C. After 180 minutes, the metal leaching rate was 93.5%.

Example 4

Electrolytically produced chlorine leaching was carried out using 400 mL of 1M HCl solution using waste electronic equipment scrap containing about 45.7% of the metal leachate and Cu as the main metal constituent. At this time, the average particle size of the crushed scrap used was between 0.6mm ~ 1.2mm was used 10g in the leaching experiment. The anode was made of graphite of 50 cm ² and the cathode was made of titanium. The applied current was 10 mA / cm ² , agitation speed 800 rpm, and a solution temperature of 30 ° C. After 180 minutes, the metal leaching rate was 91.5%.

The chlorine leaching method electrolytically produced according to the present invention uses a low concentration of acid as an electrolyte and does not require additional chlorine supply during the leaching reaction, so the efficiency of the process is very high and the risk of external chlorine leakage is extremely low. Compared to the above, there is a very high stability advantage. In addition, the configuration of the electrolytic leaching apparatus according to the present invention has the advantage of high energy efficiency of the process because the electrolytic precipitation of the leaching metal component at the same time as the leaching by the electro-generated chlorine is made at the same time.

Claims (11)

A valuable metal electrolytic leaching method for leaching valuable metals by chlorine produced by applying an oxidation current or voltage to an anode supported on an electrolyte containing chlorine ions. The method of claim 1, Electrolytic solution is a valuable metal electrolytic leaching method for leaching valuable metals by chlorine, characterized in that consisting of a solution of chlorine ions and acid, salts or mixtures thereof. Introducing a leaching sample containing a metal component into the leaching solution of the leaching reaction chamber containing chlorine ions; An electrolytic generation step of generating chlorine by applying a current or voltage to the anode of the leaching reaction chamber; A leaching reaction step of reacting chlorine with a leaching sample at the same time as electrolysis of chlorine; Valuable metal electrolytic leaching method of leaching valuable metals by chlorine comprising a. The method of claim 3, wherein A valuable metal electrolytic leaching method for leaching valuable metals by chlorine having the step of reducing and recovering the leached valuable metals at the cathode. The method of claim 4, wherein Valuable metal electrolytic leaching method for leaching the valuable metal by chlorine, characterized in that the anode and the cathode are separated by a separator. The method according to any one of claims 3 to 5, Valuable metal electrolytic leaching method of leaching the valuable metal by chlorine, characterized in that to promote the leaching step by stirring with a stirring rod to the anode. The method of claim 6, A valuable metal electrolytic leaching method of leaching valuable metals by chlorine, characterized in that the stirring rod is fixed to the leaching reaction chamber and further provided with a lid. An apparatus for leaching valuable metals by chlorine comprising a leaching reaction chamber, a leaching metal recovery reaction chamber, an electrolytic chlorine generating electrode in the leaching reaction chamber, and a reducing electrode in the leaching metal recovery reaction chamber. The method of claim 8, The leaching reaction chamber is a valuable metal electrolytic leaching device by chlorine, characterized in that it further comprises a stirring motor and a sealing cover for driving the stirring rod and the stirring rod. The method of claim 8 The separator is a valuable metal electrolytic leaching device by the chlorine consisting of a separator, an ion exchange membrane or a combination thereof, which passes the leached metal ions and the solid or electrolytically produced chlorine does not pass. The method of claim 8 The anode is a valuable metal electrolytic leaching apparatus, characterized in that made of a material that is electrochemically stable when the oxidation current or voltage is applied during the electrolytic generation of chlorine and chemically stable to the oxidation of the chlorine generated electrolytically.

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