JP7443284B2 - Reaction method and reaction tank - Google Patents

Description

The present invention relates to a reaction method and a reaction vessel.

In the copper smelting process, raw materials mainly containing copper concentrate are pyrometallurgically smelted to produce blister copper with a grade of approximately 99%, and then electrolytic copper is produced by electrolytic refining. When valuable metals are recovered from the electrolytic precipitate obtained during electrolytic refining, there is a step of leaching the electrolytic precipitate or its intermediates using hydrochloric acid or an oxidizing agent. Such a leaching process generates reaction heat and must be carried out while cooling, but since highly corrosive acids such as hydrochloric acid are used and the temperature of the leaching solution is relatively high, for example, For cooling, a cooling pipe made of resin with high corrosion resistance was installed in the reaction tank (for example, see Patent Document 1).

Japanese Patent Application Publication No. 2001-215094

However, if a cooling pipe is installed in the reaction tank to directly cool the leachate, the cooling state of the leachate becomes uneven, and there is a drawback that casting tends to occur in locally overcooled areas. Yes. When casting occurs, it gradually grows, causing a problem in that recovery of valuable metals that should originally be recovered by leaching is delayed. In addition, the growth of castings obstructs the flow of the liquid and deteriorates the agitation condition in the reaction tank, resulting in the problem that substances with high specific gravity, such as precious metals, tend to settle without being agitated.

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a reaction method and a reaction tank that can uniformize the cooling state within the tank.

The reaction method according to the present invention is a reaction method in which an electrolytic precipitate of a non-ferrous metal or an intermediate obtained by wet-processing the electrolytic precipitate is subjected to an exothermic reaction in an acidic hydrochloric acid aqueous solution, wherein the hydrochloric acid acidic aqueous solution is contained. The exothermic reaction is caused while cooling the hydrochloric acid acidic aqueous solution by flowing a cooling medium into a plurality of cooling jackets installed on the outer periphery of the side wall of the reaction tank , and the plurality of cooling jackets are provided separately from each other, The cooling jacket is characterized in that a channel is provided inside the cooling jacket, through which a cooling medium flows in the circumferential direction of the outer periphery of the reaction tank .

The electrolytic precipitate or the intermediate may contain a noble metal. The exothermic reaction may be a leaching reaction. The electrolytic precipitate or the intermediate may contain SiO ₂ . The intermediate may be an intermediate obtained by wet-processing a copper electrolytic precipitate. The intermediate may be a leaching residue obtained after leaching the copper electrolytic precipitate to remove copper. After the hydrochloric acid acidic aqueous solution is extracted from the reaction tank, the casting adhering to the inner wall of the reaction tank may be cleaned by hydraulic pressure of a cleaning liquid. During the cleaning, a plurality of sprays may be used which are suspended by a rod in the vertical direction and sprayed onto the rod toward the outer periphery of the reaction tank, and spraying may be carried out while moving the rod in the vertical direction. The hydraulic pressure of the cleaning liquid may be 0.1 MPa or more. The rod may be rotated horizontally so that the amount of washing water per unit area of the casting attachment portion may be 10 L/cm ² or more. Titanium may be used as the material of the cooling jacket. Titanium may be used as the material of the reaction tank. The temperature of the cooling medium introduced into the cooling jacket may be within a temperature range of 20° C. or higher and lower than the temperature of the hydrochloric acid aqueous solution.

The reaction tank according to the present invention is a reaction tank in which an electrolytic precipitate of a nonferrous metal or an intermediate obtained by wet-processing the electrolytic precipitate is subjected to an exothermic reaction in an acidic aqueous solution of hydrochloric acid, and the reaction tank is cooled on the outer periphery of the side wall of the reaction tank. A plurality of cooling jackets are provided to allow a medium to pass therethrough, and the plurality of cooling jackets are provided separately from each other, and inside the plurality of cooling jackets, there is a channel through which a cooling medium flows in a circumferential direction of the outer periphery of the reaction tank. It is characterized by being provided with .

The reactor may have cleaning equipment for cleaning the casting deposited on the inner wall of the reaction tank by using hydraulic pressure of a cleaning liquid after the hydrochloric acid acidic aqueous solution is extracted from the reaction tank. The cleaning equipment may be suspended by a rod in the vertical direction, and a plurality of sprayers for spraying toward the outer periphery of the reaction tank may be attached to the rod, and the rod may be installed so that the rod can be operated in the vertical direction. The hydraulic pressure of the cleaning liquid may be 0.1 MPa or more. The cleaning equipment may rotate the rod in a horizontal direction, and the amount of cleaning water per unit area of the casting attachment portion may be 10 L/cm ² or more. The material of the cooling jacket may be titanium. The material of the reaction tank may be titanium.

According to the present invention, it is possible to provide a reaction method and a reaction tank that can uniformize the cooling state within the tank.

(a) and (b) are diagrams illustrating reaction vessels according to comparative embodiments. (a) and FIG. 2(b) are diagrams illustrating the reaction tank according to the embodiment. (a) and (b) are views illustrating a spray suspended by a rod; FIG. 2 is a diagram showing the results of Example 1 and Example 2.

Hereinafter, a reaction tank and a chloride leaching method according to an embodiment will be described in detail with reference to the drawings.

(Embodiment)
The solid substance targeted in this embodiment is an electrolytic precipitate of a non-ferrous metal such as copper, silver, or lead, or an intermediate obtained by wet-processing the electrolytic precipitate. The intermediate is, for example, an intermediate obtained by wet-processing a copper electrolytic precipitate. The intermediate is, for example, a leaching residue obtained after copper-removal leaching of a copper electrolytic precipitate. Wet processing is a wet processing performed to separate some components of electrolytic precipitates, and includes processing using chemical reactions such as leaching, and physical sorting such as specific gravity sorting and classification sorting performed by wet methods. Also includes processing.

In the copper smelting process, raw materials mainly containing copper concentrate are pyrometallurgically smelted to produce blister copper with a grade of approximately 99%, and then electrolytic copper is produced by electrolytic refining. In electrolytic refining of copper (Cu), blister copper from a converter is refined to approximately 99.5 wt% in a refining furnace, and a cast anode and a seed plate as a cathode are hung alternately in an electrolytic tank, and electrolytic refining is carried out. Implement. Impurities contained in the anode are deposited in the form of mud at the bottom of the electrolytic cell. This muddy deposit is called a copper electrolyte (anode slime). In addition to copper, metals such as gold (Au), platinum (Pt), palladium (Pd), and selenium (Se) are concentrated in the copper electrolytic precipitate.

By subjecting this copper electrolytic precipitate to chloride leaching, gold, platinum, palladium, selenium, etc. can be leached out. Alternatively, the copper contained in the copper electrolytic precipitate can be removed by wet treatment such as leaching out with a sulfuric acid solution, followed by solid-liquid separation and repulping with hydrochloric acid. By doing this, gold, platinum, palladium, selenium, etc. are leached out.

The copper electrolytic precipitate contains, for example, 3.0 mass% to 33 mass% of copper, 0.6 mass% to 4.0 mass% of gold, 0.006 mass% to 0.06 mass% of platinum, and 0.03 mass% of palladium. % to 0.3 mass%, selenium of 6.0 mass% to 25 mass%, and SiO ₂ of 3.0 mass% to 36 mass%. In this way, the copper electrolytic precipitate partially contains noble metals. The reason why the amount of SiO ₂ is large is that SiO ₂ is easily mixed into the copper electrolytic precipitate by using radiolite as a filter aid for filtering out suspended matter in the electrolytic process.

The decoppered precipitate slurry contains 0.8 mass% to 7.4 mass% of gold, 0.008 mass% to 0.1 mass% of platinum, 0.04 mass% to 0.6 mass% of palladium, and 7.5 mass% of selenium. It contains 6 mass% to 46 mass%, and 3.8 mass% to 66 mass% of SiO ₂ . In this way, some of the intermediates also contain precious metals.

Silver deposits and lead deposits also contain precious metals such as gold, although there are differences in their content, so they require hydrochloric acid treatment in the same way as copper deposits. For example, the lead precipitate contains 5 mass% to 15 mass% of lead, 15 mass% to 20 mass% of silver, 4 mass% to 9 mass% of copper, 25 mass% to 34 mass% of antimony, and 14 mass% to 22 mass% of bismuth. Contains 300g/t to 500g/t of gold, and also contains tellurium, selenium, tin, etc.

Further, the silver precipitate contains, for example, about 60 mass% gold, about 25 mass% silver, and about 15 mass% platinum group elements. Note that when hydrochloric acid is used as a leaching solution for both lead precipitates and silver precipitates, silver has a low solubility and therefore exists as a solid like SiO ₂ . Therefore, like SiO ₂ , it is thought that it may be a cause of casting development.

In the chlorination leaching step, hydrochloric acid and hydrogen peroxide are used as a leaching solution, and reactions as shown in the following formulas (1) to (4) occur, for example.
3Au+3H ₂ O ₂ +8HCl→2HAuCl ₄ +6H ₂ O (1)
Pt+2H ₂ O ₂ +6HCl→H ₂ PtCl ₆ +4H ₂ O (2)
Pd+H ₂ O ₂ +4HCl→H ₂ PdCl ₄ +2H ₂ O (3)
Se+2H ₂ O ₂ →H ₂ SeO ₃ +H ₂ O (4)

Since the chloride leaching reactions shown in formulas (1) to (4) above are exothermic reactions, there is a risk that the temperature of the reaction tank may rise excessively. Therefore, it is desirable to control the temperature of the leachate within a predetermined temperature range (for example, 70°C to 75°C) using a heat exchanger.

For example, it is conceivable to control the temperature of the leachate in the reaction tank within a predetermined range by providing a cooling pipe through which a cooling medium such as cooling water flows inside the inner surface of the side wall of the reaction tank.

FIGS. 1A and 1B are diagrams illustrating a reaction tank 20 according to a comparative embodiment. FIG. 1(a) is a top view of the reaction tank 20. FIG. 1(b) is a transparent diagram of the reaction tank 20. As illustrated in FIGS. 1(a) and 1(b), a cooling pipe 21 is provided inside the inner surface of the side wall of the reaction tank 20. The leachate is cooled by flowing a cooling medium such as cooling water through the cooling pipe 21 . However, the area around the cooling pipe 21 is intensively cooled, and the cooling state of the exudate becomes non-uniform. In this case, there is a risk that cast-off may occur in locally supercooled areas, and when cast-off occurs, it gradually grows, causing a problem that recovery of valuable metals that should originally be recovered by leaching is delayed. In addition, the growth of castings obstructs the flow of the liquid and deteriorates the agitation condition in the reaction tank, resulting in the problem that substances with high specific gravity, such as precious metals, tend to settle without being agitated. Up until now, the amount of _SiO2 contained in copper electrolytic precipitates and decoppered precipitate slurry was small, so casting was low, but in recent years, the amount of _SiO2 contained in copper electrolytic precipitates and decoppered precipitate slurries has decreased. As the amount of casting increases, countermeasures against casting become necessary.

Therefore, in this embodiment, a cooling jacket is provided around the outer periphery of the side wall of the reaction tank 10. FIGS. 2(a) and 2(b) are diagrams illustrating the reaction tank 10 according to the embodiment. FIG. 2(a) is a top view of the reaction tank 10. FIG. 2(b) is a front view of the reaction tank 10. As illustrated in FIGS. 2(a) and 2(b), a cooling jacket 11 is provided around the outer periphery of the side wall of the reaction tank 10. Inside the cooling jacket 11, piping and the like are provided through which a cooling medium such as cooling water flows. For example, inside the cooling jacket 11, a plurality of pipes are provided that are wound around the side wall of the reaction tank 10 in the circumferential direction. A cooling medium flows into these pipes from the inflow pipe 12. Further, the cooling medium is discharged from these pipes via the discharge pipe 13. By arranging the cooling jacket 11 outside the side wall of the reaction tank 10, the number of members that obstruct the flow of the leachate in the reaction tank 10 is reduced, and stirring in the reaction tank 10 becomes uniform, suppressing local cooling. , the cooling state inside the reaction tank 10 can be made uniform. As a result, the occurrence of casting can be suppressed. If the occurrence of casting on the cooling surface is suppressed, the cooling efficiency is maintained and the reaction efficiency of chloride leaching in the reaction tank 10 is improved.

Note that by arranging the cooling jacket 11 outside the reaction tank 10, the cooling effect of the cooling medium is transmitted into the reaction tank 10 via the side wall of the reaction tank 10, and the cooling effect of the cooling medium is transmitted to the side wall of the reaction tank 10. It is also possible to obtain the effect that the cooling state within the reaction tank 10 can be made uniform by spreading throughout the reaction tank 10.

In order to maintain the temperature of the leachate at 70°C to 75°C, for example, and to keep the amount of castings on the wall to a level that can be washed with water, the temperature of the cooling medium introduced into the cooling jacket 11 must be set at a lower limit. It is preferable to provide For example, it is desirable that the temperature of the cooling medium introduced into the cooling jacket 11 be 20° C. or higher, and further desirably 25° C. or higher to make cleaning easier. On the other hand, the upper limit may be a temperature that does not exceed the upper limit of the temperature range in which the temperature of the leachate is desired to be maintained, and can be set to be lower than the leachate temperature, for example, 40° C. or lower. Note that in order to maintain the leachate temperature within a predetermined temperature range, the flow rate of the cooling medium, etc. may be adjusted instead of the temperature of the cooling medium.

The material of the cooling jacket is not particularly limited, but titanium is preferable in order to improve thermal conductivity. The material of the reaction tank 10 is not particularly limited, but titanium is preferable in order to improve thermal conductivity. The material of the cooling jacket and the reaction tank 10 may be a nickel alloy or the like.

Note that even if the cooling state in the reaction tank 10 is made uniform and the occurrence of casting is suppressed, if chloride leaching in the reaction tank 10 is repeated, casting may occur. Therefore, it is preferable to provide cleaning equipment for cleaning the casting deposited on the inner wall of the reaction tank 10 using hydraulic pressure after extracting the leachate from the reaction tank 10. Therefore, in this embodiment, it is preferable that a sprayer be provided inside the reaction tank 10.

3(a) and 3(b) are diagrams illustrating the spray 15 suspended by the rod 14. As illustrated in FIGS. 3(a) and 3(b), the sprayer 15 is suspended by a rod 14 in the vertical direction and sprays toward the inner wall of the reaction tank 10. The sprays 15 are provided at multiple locations on the rod 14.

The rod 14 moves in the vertical direction. Rod 14 is horizontally rotatable. Thereby, the spray 15 can spray evenly toward the inner wall at each height in the reaction tank 10. The water pressure in spraying is preferably 0.1 MPa or more, and more preferably 0.4 MPa or more in order to enhance the removal effect by water pressure. It is preferable to rotate the rod 14 in the horizontal direction so that the amount of cleaning water per unit area of the casting attachment portion is 10 L/cm ² or more.

Note that, in order to prevent the residue accumulated at the bottom of the reaction tank 10 from remaining, a liquid containing the residue may be extracted from the bottom of the reaction tank 10 and reintroduced from the top of the reaction tank 10.

Hydrochloric acid and hydrogen peroxide were added to the copper-decoppered precipitate slurry obtained by decoppering and leaching the copper electrolytic precipitate using the reaction tank 10 according to the embodiment described above to perform chloride leaching. Chloride leaching was a batch process. That is, when performing chloride leaching multiple times, all the slurry in the reaction tank was extracted after the chloride leaching reaction was completed, new decopper-removed slurry was received, and chloride leaching was performed. The leachate temperature during chloride leaching was cooled to maintain it at 70 to 75°C.

(Example 1)
In Example 1, chloride leaching was performed multiple times while cooling water was passed through the cooling jacket 11 as a cooling medium. At each interval of chloride leaching, water washing was performed using the spray 15 (water pressure 0.1 MPa) while rotating the rod 14. The temperature of the cooling medium was adjusted to be between 10°C and 19°C.

(Example 2)
In Example 2, chloride leaching was performed multiple times while cooling water was passed through the cooling jacket 11 as a cooling medium. In Example 2, water washing with Spray 15 was not performed at each chloride leaching interval. The temperature of the cooling medium was adjusted to be between 10°C and 19°C.

Regarding Example 1 and Example 2, the cooling capacity of the reaction tank 10 was investigated. This is the result of calculating the overall heat transfer coefficient for each time when chloride leaching was performed for the total number of times (approximately 70 times) in Example 1 and Example 2, and plotting the results with the horizontal axis representing the order of implementation. The results marked with "▲" are the results of calculating the overall heat transfer coefficient for the times in which chloride leaching was performed after washing with water using the method of Example 1. The data marked with "●" is the result of calculating the overall heat transfer coefficient when the next chloride leaching was performed without washing with water as in Example 2. The results are shown in Figure 4. As shown in FIG. 4, in both Example 1 and Example 2, generally good cooling ability was continuously maintained. This is considered to be because the provision of the cooling jacket 11 outside the side wall of the reaction tank 10 made the cooling state inside the reaction tank 10 uniform and suppressed the occurrence of casting.

As a result of comparing Example 1 and Example 2, it was found that Example 1 maintained a higher cooling capacity. This is thought to be because the casting could be cleaned by washing with water using the spray 15.

(Example 3)
In Example 3, chloride leaching was performed multiple times while cooling water was passed through the cooling jacket 11 as a cooling medium. The temperature of the cooling medium was adjusted to be between 20°C and 28°C.

(Comparative example)
In the comparative example, as shown in FIGS. 1(a) and 1(b), cooling water was flowed as a cooling medium into a cooling pipe provided inside the inner wall of the reaction tank.

The amount of casting generated in the reaction tank kg/year was quantified. The results are shown in Table 1. In addition, Table 2 shows the results of component analysis of the casting. As shown in Table 1, in the comparative example, the amount of casting occurrence increased significantly. This is thought to be because the cooling pipe inside the reaction tank was used for cooling. On the other hand, in Example 1, the amount of cast-off occurrence was extremely small. This is thought to be due to cooling using a cooling jacket provided around the outer periphery of the reaction tank. In addition, Example 1 in Table 1 shows cases in which the temperature of the cooling medium was adjusted to between 10°C and 19°C and the water washing described above was performed and the case in which the water washing was not performed. include. In Example 3, the amount of cast-off occurrence was further reduced. This is considered to be because the temperature of the cooling medium was set to 20° C. or higher.

The embodiments described above are examples of preferred implementations of the present invention. However, the present invention is not limited to this, and various modifications can be made without departing from the gist of the present invention.

10 Reaction tank 11 Cooling jacket 12 Inflow pipe 13 Discharge pipe 14 Rod 15 Spray

Claims (20)

A reaction method in which an electrolytic precipitate of a nonferrous metal or an intermediate obtained by wet-processing the electrolytic precipitate is subjected to an exothermic reaction in an acidic aqueous solution of hydrochloric acid, the method comprising:
causing the exothermic reaction while cooling the hydrochloric acid acidic aqueous solution by flowing a cooling medium into a plurality of cooling jackets installed on the outer periphery of the side wall of the reaction tank containing the hydrochloric acid acidic aqueous solution,
The plurality of cooling jackets are provided separately from each other,
A reaction method characterized in that a flow path through which a cooling medium flows in a circumferential direction of the outer periphery of the reaction tank is provided inside the plurality of cooling jackets . 2. The reaction method according to claim 1, wherein the electrolytic precipitate or the intermediate contains a noble metal. 3. The reaction method according to claim 1, wherein the exothermic reaction is a leaching reaction. The reaction method according to any one of claims 1 to 3, wherein the electrolytic precipitate or the intermediate contains _SiO2 . 5. The reaction method according to claim 1, wherein the intermediate is an intermediate obtained by wet-processing a copper electrolytic precipitate. 6. The reaction method according to claim 5, wherein the intermediate is a leaching residue obtained after leaching the copper electrolytic precipitate to remove copper. According to any one of claims 1 to 6, the molding adhered to the inner wall of the reaction tank is cleaned by hydraulic pressure of a cleaning liquid after the hydrochloric acid acidic aqueous solution is extracted from the reaction tank. reaction method. 8. The reaction method according to claim 7, wherein the liquid pressure of the cleaning liquid is 0.1 MPa or more. 9. The reaction method according to claim 1, wherein titanium is used as a material for the cooling jacket. 10. The reaction method according to claim 1, wherein titanium is used as a material for the reaction tank. The reaction method according to any one of claims 1 to 10, characterized in that the temperature of the cooling medium introduced into the cooling jacket is set in a temperature range of 20°C or higher and lower than the temperature of the hydrochloric acid acidic aqueous solution. A reaction method in which an electrolytic precipitate of a nonferrous metal or an intermediate obtained by wet-processing the electrolytic precipitate is subjected to an exothermic reaction in an acidic aqueous solution of hydrochloric acid, the method comprising:
causing the exothermic reaction while cooling the hydrochloric acid acidic aqueous solution by flowing a cooling medium into a cooling jacket installed on the outer periphery of the reaction tank in which the hydrochloric acid acidic aqueous solution is stored;
After extracting the hydrochloric acid acidic aqueous solution from the reaction tank, the casting adhering to the inner wall of the reaction tank is cleaned by hydraulic pressure of a cleaning liquid,
A reaction method characterized in that, during the cleaning, a plurality of sprays are suspended vertically by a rod and are sprayed onto the rod toward the outer periphery of the reaction tank, and spraying is performed while the rod is moved vertically. . 13. The reaction method according to claim 12, wherein the rod is rotated in a horizontal direction, and the amount of washing water per unit area of the casting attachment portion is set to 10 L/cm ² or more. A reaction tank in which an electrolytic precipitate of a non-ferrous metal or an intermediate obtained by wet-processing the electrolytic precipitate is subjected to an exothermic reaction in an acidic aqueous solution of hydrochloric acid,
A plurality of cooling jackets are provided for passing a cooling medium around the outer periphery of the side wall of the reaction tank ,
The plurality of cooling jackets are provided separately from each other,
A reaction tank characterized in that a flow path through which a cooling medium flows in a circumferential direction of an outer periphery of the reaction tank is provided inside the plurality of cooling jackets . 15. The reaction tank according to claim 14, further comprising a cleaning facility for cleaning the casting adhered to the inner wall of the reaction tank using hydraulic pressure of a cleaning liquid after the hydrochloric acid acidic aqueous solution is extracted from the reaction tank. 16. The reaction tank according to claim 15 , wherein the liquid pressure of the cleaning liquid is 0.1 MPa or more. 17. The reaction tank according to claim 14, wherein the material of the cooling jacket is titanium. The reaction tank according to any one of claims 14 to 17 , wherein the material of the reaction tank is titanium. A reaction tank in which an electrolytic precipitate of a non-ferrous metal or an intermediate obtained by wet-processing the electrolytic precipitate is subjected to an exothermic reaction in an acidic aqueous solution of hydrochloric acid,
A cooling jacket for passing a cooling medium around the outer periphery of the reaction tank,
having cleaning equipment for cleaning the casting adhered to the inner wall of the reaction tank by hydraulic pressure of a cleaning liquid after extracting the hydrochloric acid acidic aqueous solution from the reaction tank;
The cleaning equipment is suspended by a rod in the vertical direction, and a plurality of sprayers that spray in the direction of the outer circumference of the reaction tank are attached to the rod,
A reaction tank characterized in that the rod is installed so that it can move in the vertical direction. 20. The reaction tank according to claim 19 , wherein the cleaning equipment rotates the rod in a horizontal direction and sets the amount of cleaning water per unit area of the casting attachment part to 10 L/cm2 ^or more.

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