JP7180087B2 - Pressurized reactor and method for leaching valuable metals using the same - Google Patents

Description

Application of Article 30, Paragraph 2 of the Patent Act The summary of the lecture at the 82nd Annual Meeting of the Society of Chemical Engineers held from March 6 to 8, 2017 was published at the following website address (published on February 20, 2017). Also presented at the same conference. http://www3. scej. org/meeting/82a/

The present invention relates to a pressurized reactor and a method for leaching valuable metals using the same.

2. Description of the Related Art As a reaction apparatus such as a chemical plant, a chemical treatment is often performed by introducing a gas into a liquid phase such as a liquid or a slurry in a reaction vessel while stirring and reacting the gas.

For example, U.S. Pat. No. 5,400,000 includes a shaft rotatable about the longitudinal axis of the vessel and first and second axially spaced radially extending impellers attached to the shaft. A mixing vessel is disclosed. Specifically, in this mixing vessel, the first impeller includes a plurality of curved blades operable to move the fluid axially toward the second impeller, the second impeller axially It includes a plurality of curved blades operable to move fluid toward the first impeller, and a gas inlet is provided in the bottom surface of the vessel. With such a configuration, a strong turbulence region is generated in the central portion of the mixing vessel, making it possible to easily control the mixing of the liquids in the vessel.

However, in the mixing container described in Patent Document 1, when large bubbles are introduced from the large gas inlet provided in the center, they reach the liquid surface at the top of the mixing container before the diameter of the bubbles becomes small within the mixing container. There is a problem that Therefore, even if such a mixing vessel is applied as a reaction vessel for chemical reactions, the amount of gas that does not contribute to the reaction increases, resulting in a decrease in reaction efficiency.

This means that it is important for the gas used in the chemical reaction in the reaction vessel to have a small bubble diameter in the liquid phase inside the vessel. In addition, since the air bubbles circulate and stay in the liquid for a longer time, the amount of gas components dissolved in the liquid phase increases, and as a result, the gas concentration in the liquid phase increases, and the effect of improving the reaction efficiency can be expected. It is from. In other words, in the reaction vessel, it is important to make the gas to be introduced into small bubbles in the liquid phase and maximize the amount of bubbles.

Techniques for reducing the diameter of bubbles in a liquid phase include a method using a sparger (air diffuser) and a method in which gas is blown under a stirring blade to split the bubbles with the blade. For example, it is known that when the amount of gas blown is large, the stirring blades idle due to the flooding phenomenon, and the amount of gas dissolved in the liquid decreases. A technique is disclosed in which a ring sparger with a larger diameter is used to entrain blown bubbles in a liquid flow circulating within the device.

However, when trying to apply the sparger to a pressurized reactor that introduces gas, the pressure of the gas blown into the device from the sparger is the sum of the internal pressure of the reaction vessel and the pressure loss of the sparger. You have to over pressurize. In addition, since the sparger has a small bubble outlet diameter, the pressure loss is large, so there is a problem that the cost of pressurization equipment is high. In addition, depending on the reaction, reaction products including intermediates and post-reaction residue may clog the small bubble outlets of the sparger. There is also the problem that the Due to these various problems, it has been difficult to use a sparger in a pressurized reactor.

In a pressurized reactor into which gas is introduced, it is preferable to maximize the diameter of the gas-injecting pipe and the outlet diameter to minimize pressure loss. However, it is well known that the bubble diameter of bubbles discharged from the gas blowing pipe depends on the outlet diameter of the gas blowing pipe, and minimizing the pressure loss results in a large bubble diameter. An increase in bubble diameter means that the flooding phenomenon is likely to occur and the area of the gas-liquid interface is reduced, which is not preferable. For this reason, there has been a demand for a technique for reducing the diameter of large-diameter bubbles discharged from a large-diameter outlet with small pressure loss.

Furthermore, if the amount of gas introduced is increased in order to promote the chemical reaction within the chemical reaction device, the flooding phenomenon is more likely to occur as described above. Therefore, there has been a demand for a technology that reduces the diameter of large-diameter bubbles released from a large outlet with small pressure loss and makes the flooding phenomenon less likely to occur even if the amount of gas introduced increases.

Japanese translation of PCT publication No. 2009-536095 JP 2014-113564 A

SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances, and is capable of efficiently dividing gas bubbles introduced into an apparatus to reduce the diameter of the bubbles, and at the same time, increasing the amount of introduced gas. An object of the present invention is to provide a pressurized reactor capable of suppressing the occurrence of flooding.

The present inventors have made extensive studies to solve the above-described problems. As a result, in a pressurized reactor equipped with a stirrer and a gas-injection tube, by arranging the outlet position of the gas-injection tube at a specific position and direction with respect to the agitator, gas bubbles can be efficiently generated. The inventors have found that even if the amount of gas introduced is increased, the generation of the flooding phenomenon can be suppressed, and the present invention has been completed. That is, the present invention provides the following.

(1) A first aspect of the present invention is a pressurized reactor comprising a stirrer and a gas-injecting pipe, wherein the stirrer includes a stirring shaft suspended from the top of the pressurized reactor, and a stirring blade provided perpendicular to the stirring shaft, and when the pressurized reaction device is viewed from the front in a cross section along the axial direction of the stirring shaft, a line extending from the stirring shaft When the height of the stirring blade from the position where it intersects with the inner wall of the pressure reaction device is H, and the maximum length of the stirring blade from the center of the stirring shaft is R, the outlet center of the gas injection pipe is Provided at a position that satisfies the following formula, where h is the height from the position where the line extending from the stirring shaft intersects the inner wall of the pressurized reactor, and r is the distance from the center of the stirring shaft. , the outlet of the gas blowing pipe is arranged so that the gas blowing direction at the outlet is in the direction away from the line extending from the stirring shaft and in the downward direction or the upward direction. .
0.5H≦h≦0.8H
0.7R≤r≤1.3R

(2) A second aspect of the present invention is a pressurized reactor comprising a stirrer and a gas-injecting pipe, wherein the stirrer includes a stirring shaft suspended from the top of the pressurized reactor, and a stirring blade provided perpendicular to the stirring shaft, and when the pressurized reaction device is viewed from the front in a cross section along the axial direction of the stirring shaft, a line extending from the stirring shaft When the height of the stirring blade from the position where it intersects with the inner wall of the pressure reaction device is H, and the maximum length of the stirring blade from the center of the stirring shaft is R, the outlet center of the gas injection pipe is Provided at a position that satisfies the following formula, where h is the height from the position where the line extending from the stirring shaft intersects the inner wall of the pressurized reactor, and r is the distance from the center of the stirring shaft. , the outlet of the gas blowing pipe is arranged so that the gas blowing direction at the outlet is in the direction away from the line extending from the stirring shaft and in the downward direction or the upward direction. .
0.4H≦h≦0.8H
0.7R≤r≤1.5R

(3) A third aspect of the present invention is the second aspect, wherein the outlet center of the gas blowing pipe is provided at a position satisfying the following formula, and the outlet of the gas blowing pipe is the gas at the outlet. The pressurized reactor is arranged such that the blowing direction is away from the line extending from the stirring shaft and downward.
0.4H≦h≦0.6H
1.4R≤r≤1.5R

(4) In a fourth aspect of the present invention, in the second aspect, the outlet center of the gas blowing pipe is provided at a position satisfying the following formula, and the outlet of the gas blowing pipe is the gas at the outlet. The pressurized reactor is arranged such that the blowing direction is away from the line extending from the stirring shaft and upward.
0.45H≦h≦0.65H
1.1R≤r≤1.4R

(5) A fifth invention of the present invention is the pressurized reactor according to any one of the first to fourth inventions, wherein the outlet diameter of the gas injection pipe is 10 mm to 150 mm.

(6) A sixth invention of the present invention is a pressurized reaction device, which is an autoclave device in any one of the first to fifth inventions.

(7) In a seventh aspect of the present invention, in any one of the first to sixth aspects, the slurry containing the mixed sulfide of nickel and cobalt is subjected to a leaching treatment by adding an acid under high temperature and pressure. It is a pressurized reactor used for

(8) An eighth invention of the present invention is a leaching of valuable metals, wherein valuable metals are leached from solids contained in a slurry using the pressurized reactor according to any one of the first to seventh inventions. processing method.

ADVANTAGE OF THE INVENTION According to the present invention, it is possible to efficiently divide the gas bubbles introduced into the apparatus so as to have a small bubble diameter, and to suppress the occurrence of the flooding phenomenon even if the amount of introduced gas is increased. A pressure responsive device can be provided.

In addition, by performing a leaching process in which valuable metals contained in the solid matter in the slurry are leached out using such a pressurized reaction apparatus, the amount of bubbles in the liquid phase increases, thereby increasing the reaction efficiency and effectively Valuable metals can be leached into the liquid immediately.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows the structure of an autoclave apparatus, (a) is the cross-sectional plan view which cut|disconnected the autoclave apparatus horizontally and showed the internal structure typically, (b) cut|disconnects the autoclave apparatus vertically, and is a figure which shows an internal structure. It is a longitudinal side view schematically showing the. FIG. 1(a) is a schematic diagram showing a cross section along AA in FIG. 1(a), and is a diagram for explaining a stirred flow by a stirrer. FIG. 3 is a schematic diagram showing a BB cross section in FIG. 2, and is a diagram for explaining a stirred flow by a stirrer. FIG. 2 is a schematic diagram showing a cross section along the stirring shaft of the autoclave apparatus according to the present embodiment, and is a diagram for explaining the arrangement of outlet positions of gas blowing pipes. (a) is a schematic front view of the cross section of the autoclave device according to the first embodiment along the axial direction of the stirring shaft, and (b) is a top view of the cross section of the same device perpendicular to the stirring shaft; It is a schematic diagram. (a) is a schematic front view of a cross section of the autoclave apparatus according to the second embodiment along the axial direction of the stirring shaft, and (b) is a top view of the cross section of the same apparatus perpendicular to the stirring shaft; It is a schematic diagram. (a) is a schematic front view of the cross section of the autoclave apparatus according to the third embodiment along the axial direction of the stirring shaft, and (b) is a top view of the cross section of the same apparatus perpendicular to the stirring shaft. It is a schematic diagram.

Specific embodiments of the present invention (hereinafter referred to as "present embodiments") will be described in detail below. In addition, the present invention is not limited to the following embodiments, and various modifications are possible without changing the gist of the present invention. Further, in this specification, the notation "X to Y" (X and Y are arbitrary numerical values) means "X or more and Y or less".

The pressurized reaction apparatus according to the present embodiment is equipped with a stirrer and a gas-injecting pipe, and enables reaction under high pressure. This pressurized reaction apparatus can be applied, for example, as an autoclave apparatus, which is a heat-resistant and pressure-resistant reaction vessel whose interior is heated to a high temperature and a high pressure with saturated steam. In the following, the autoclave device and the chemical reaction that takes place in the device will be specifically described, but the present invention is not limited to this. A similar effect can be obtained if the device is a reaction device.

FIG. 1 is a diagram showing the configuration of an autoclave apparatus. FIG. 1(a) is a cross-sectional plan view schematically showing the internal structure of the autoclave device 1 cut horizontally, and FIG. 1(b) is a schematic illustration of the internal structure of the autoclave device 1 cut vertically. 2 is a vertical cross-sectional side view shown in FIG. As shown in FIG. 1, the autoclave apparatus 1 has, for example, a cylindrical container installed horizontally.

The autoclave apparatus 1 is, for example, a raw material slurry containing a mixed sulfide (solid matter) containing at least nickel and cobalt as a liquid phase (suspension of raw material solid matter and leachate, hereinafter simply referred to as "slurry"). ) is used for the leaching process using a solution such as sulfate. More specifically, the autoclave apparatus 1 accommodates a heated and pressurized slurry, adds an acid such as sulfuric acid, and agitates the valuable metal contained in the solid matter in the slurry at high temperature and pressure. Pressure leaching.

Valuable metals to be leached are not particularly limited, and nickel and cobalt are leached as valuable metals when a mixed sulfide of nickel and cobalt is used as the raw material solid.

As for the processing conditions in the autoclave apparatus 1, for example, the internal pressure of the apparatus is set to 3 atmospheres or higher, and the temperature is set to 100° C. or higher.

As shown in FIG. 1, the autoclave apparatus 1 comprises multiple compartments 10 . Each partitioned chamber 10 is a space that serves as a reaction field for performing treatment such as leaching treatment on the slurry in the autoclave apparatus 1 . Specifically, the partitioned chamber 10 is partitioned into a plurality of partitions 40 provided inside the autoclave apparatus 1 . In the example of the autoclave apparatus 1 shown in FIG. 1, five partitioned chambers 10 (10A, 10B, 10C, 10D, 10E) partitioned into five partitions by four partition walls 40 (40A, 40B, 40C, 40D) are provided. ing. The number of compartments in the autoclave can be appropriately set according to the raw material, leaching conditions, and the like.

Each compartment 10 is provided with at least a stirrer 20 for stirring the slurry and a gas blowing pipe 30 for supplying gas such as air to the slurry. Specifically, each compartment 10A to 10E is provided with a stirrer 20 (20A, 20B, 20C, 20D, 20E) and a gas blowing pipe 30 (30A, 30B, 30C, 30D, 30E). ing.

[Leaching treatment in the compartment]
The partitioned chambers 10 are sequentially arranged from the upstream side (left side in FIG. 1) to the first partitioned chamber 10A, the second partitioned chamber 10B, . It is composed of a compartment 10E. In the autoclave apparatus 1, a raw material slurry is charged into the most upstream first compartment 10A. supplied. In the first compartment 10A, the valuable metals contained in the solids in the slurry are leached into the solution by agitation by the agitator 20A, which will be described later, and oxygen supplied by the gas blowing pipe 30A.

While the slurry is stirred in the first compartment 10A, part of the slurry overflows the upper part of the partition 40A that separates the first compartment 10A and the second compartment 10B. , to the second compartment 10B. In the second compartment 10B, similarly to the treatment in the first compartment 10A, the leaching process proceeds sequentially by stirring with the stirrer 20B. At this time, also in the second partitioned chamber 10B, it is possible to supply a solution such as sulfuric acid, a slurry, or the like used for leaching by suspending a pipe from the upper portion thereof.

Subsequently, the slurry is transferred to the third compartment 10C and the fourth compartment 10D mainly by overflow, and the leaching process proceeds in each compartment 10 . Similarly, in the fifth compartment 10E at the most downstream side, when the slurry is subjected to the leaching process, the valuable A slurry containing the leachate obtained by leaching the metal is discharged.

[Compartment configuration]
As described above, the partitioned chamber 10 is provided with the agitator 20 for agitating the internal slurry and the gas injection pipe 30 for supplying gas such as oxygen necessary for the reaction. At least the first partitioned chamber 10A of the partitioned chambers 10 is provided with a raw material slurry charging pipe (not shown) for charging raw material slurry. Slurry containing solids is charged through.

Various supply pipes for supplying an acid solution such as sulfuric acid, slurry, steam, etc. are also attached to the compartment 10, for example, so as to hang down from the upper part thereof.

(mixer)
The agitator 20 is installed in each of the first compartment 10A to the fifth compartment 10E, and agitates the slurry charged and transferred inside each compartment 10 .

As the stirrer 20, for example, as shown in the schematic diagram of FIG. 2 showing the AA cross section of the compartment 10B in FIG. A propeller-shaped one having a plurality of stirring blades 22 provided perpendicularly to the stirring shaft 21 can be used. In this way, the stirrer 20 is suspended from the upper ceiling of each compartment 10 so that the stirring shaft 21 is positioned at the center of each compartment 10 when the autoclave apparatus 1 is viewed from above (see FIG. 1(a)). can be set to The stirrer may be provided with a plurality of pairs of propeller-shaped ones having a plurality of stirring blades on the stirring shaft.

The stirrer 20 rotates the stirring shaft 21 clockwise at a predetermined speed, for example, and stirs the slurry with the stirring blades 22 . Agitation by the agitator 20 causes the slurry in the compartment 10 to flow in a predetermined direction. In addition, in order to flow the slurry throughout the partitioned chamber 10, a liquid flow is normally generated from the stirring blade 22 in a downward direction (a direction opposite to the liquid surface in the axial direction of the stirring shaft 21). agitated so as to

(Gas blowing pipe)
A gas blowing pipe 30 is installed in each of the first compartment 10A to the fifth compartment 10E, and supplies gas components necessary for reaction of the slurry inside each compartment 10. FIG.

Here, when the autoclave apparatus 1 is used for the leaching treatment of a slurry containing at least a mixed sulfide of nickel and cobalt, the reaction during the leaching treatment of nickel sulfide and cobalt sulfide in each compartment 10 is expressed by the following equation: (1) and equation (2).
NiS+2O ₂ →NiSO ₄ (1)
CoS+2O ₂ →CoSO ₄ (2)

As shown in the above reaction formula, in the leaching treatment under high temperature and high pressure, it is necessary to supply oxygen (O ₂ ) required for the reaction into the slurry. In supplying oxygen to the slurry, air is generally supplied, and the air is supplied through the gas blowing pipe 30 .

As the gas blowing pipe 30, various forms can be adopted as described in the first to third embodiments below. Note that the gas blowing pipe 30 is not limited to the mode in which only one is provided in each of the partitioned chambers 10 as shown in FIGS.

In the autoclave apparatus 1, in addition to the gas injection pipe 30, steam for maintaining a high temperature and high pressure state, sulfuric acid for supplying an acid such as sulfuric acid to make a sulfuric acid leachate, water for the purpose of concentration adjustment, etc. Although a pipe or the like for supplying a slurry or the like may be attached as necessary, in the present embodiment, the gas injection pipe 30 is used as a pipe for supplying the gas necessary for the reaction, and other supplies It is distinguished from piping intended for the supply of

[Liquid flow in the compartment]
Here, FIG. 2 is a schematic diagram of the AA cross section of FIG. It shows the flow in the height direction. FIG. 3 is a schematic view taken along the line BB in FIG. 2, and shows the main agitation regions S generated in the compartment 10 by the agitator 20. As shown in FIG. Note that the gas blowing pipe 30 is not shown in FIGS. 2 and 3 in order to make the stirring flow easier to see.

As described above, the partitioned chamber 10 is usually stirred so that a stirring flow is generated from the stirring blades 22 in the downward direction opposite to the liquid surface. It becomes a stirring flow obliquely downward toward the wall surface 1w. Then, as shown by the arrows in FIG. 2, the main agitated flow collides with the inner wall surface 1w of the autoclave device 1 and then becomes a flow upward along the inner wall surface 1w. It flows downward along the wall surface 1w.

Therefore, the agitated flow propelled obliquely to the right in FIG. thick line arrow X in the middle) and a slow and small clockwise flow generated at the lower right of the stirrer 20 (thin line arrow Y in FIG. 2). The large counterclockwise flow, which is the main agitation flow generated by the stirrer 20, is combined with the horizontal flow parallel to the liquid surface to form a swirling upward flow.

When such a stirring flow is observed in the direction from the inner wall surface 1w toward the stirring shaft 21 along the line BB in FIG. Beyond this region, there exists a region where the agitated flow flows at a slow flow rate as indicated by the thin line arrow Y. Viewing such a churning flow from a cross section perpendicular to the churning shaft 21, as shown in FIG. It is formed. The direction of the agitation flow in this main agitation region S is in a spiral shape that goes counterclockwise outward as indicated by the arrow Z in the figure.

[Arrangement of gas injection pipe]
In the gas blowing pipe 30, the bubbles of the gas supplied from the gas blowing pipe 30 are divided by the agitated flow by the stirrer 20 to reduce the diameter, and the bubbles are put on the stirred flow to reduce the amount of bubbles in the liquid phase. It is preferable to be able to increase it.

The reason why the amount of air bubbles in the liquid phase increases by putting air bubbles on the agitated flow and causing it to flow in the liquid phase is that, as described above, in the main agitation region S, the agitated flow goes downward while swirling. This is probably because the air bubbles move with the agitated flow and reach the liquid surface for a relatively long time because the flow becomes upward after that. On the other hand, the air bubbles positioned at a location where the agitation flow is weak have a higher speed of rising toward the liquid surface due to buoyancy, and reach the liquid surface in a relatively short time. In addition, at positions where the agitation flow is weak, the coalescence of the bubbles causes the bubbles to grow in diameter, and the rising speed due to buoyancy increases depending on the bubble diameter. It's getting shorter.

On the other hand, the gas supplied from the gas blowing pipe 30 has a flow velocity (hereinafter referred to as "initial kinetic energy") according to the amount of supply. Therefore, the bubbles supplied from the gas blowing pipe 30 try to move in the direction in which the gas blowing pipe outlet 30a is facing, and actually flow in the liquid phase along with the stirring flow because the initial kinetic energy is After canceling the resistance due to the agitated flow. Considering the initial kinetic energy of the bubbles, the bubbles travel a certain distance from the gas blowing pipe outlet 30a toward the stirrer 20 and then flow in the liquid phase along with the stirring flow. This certain distance increases as the amount of gas supplied increases. Therefore, when the gas blowing pipe outlet 30a is installed in the direction toward the stirring shaft 21, as the amount of gas supplied from the gas blowing pipe 30 increases, the bubbles pass through the main stirring region S and move in the arrow Y direction. An increasing amount of the indicated agitated flow reaches the regions of low flow velocity. As a result, air bubbles tend to accumulate in the lower part of the stirring shaft 21 (the lower part of the stirring blade 22), and the flooding phenomenon tends to occur.

Therefore, in the autoclave apparatus 1 according to the present embodiment, as shown in FIGS. , are oriented in different directions.

As a result, the gas bubbles supplied from the gas blowing pipe outlet 30a are oriented perpendicularly to the stirring shaft 21 with the gas blowing direction D at the gas blowing pipe outlet 30a viewed from the front in a cross section along the stirring shaft 21. Compared to the case, the distance passing through the main stirring area S is longer, and the bubbles riding on the main stirring area S flow upward while swirling. Therefore, even if the amount of gas supplied increases, most of the bubbles will be placed on the main stirring area S, and the flooding phenomenon can be effectively suppressed.

The position and direction of the gas blowing pipe outlet 30a of the autoclave apparatus 1 according to the present embodiment will be specifically described below by dividing into three modes.

(First embodiment)
FIG. 5(a) is a schematic front view of the cross section of the autoclave device according to the first embodiment along the axial direction of the stirring shaft, and FIG. 5(b) is a cross section of the same device perpendicular to the stirring shaft. It is the schematic diagram which looked at the top surface.

The gas blowing pipe 35 of the autoclave device 1 according to the first embodiment is such that when the autoclave device 1 is viewed from the front in a cross section along the axial direction of the stirring shaft 21, a line extending from the stirring shaft 21 is the autoclave device 1 From the position where it intersects with the inner wall surface 1w to the height position of the stirring blade 22 is H, and when the maximum length of the stirring blade 22 from the center of the stirring shaft 21 is R, the center of the gas blowing pipe outlet 35a is When the height from the position where the line extending from the stirring shaft 21 intersects the inner wall surface 1w of the autoclave device 1 is h, and the distance from the center of the stirring shaft 21 is r, for example, the following equations (i) and It is provided at a position that satisfies (ii).
0.5H≦h≦0.8H (i)
0.7R≦r≦1.3R (ii)

Also, the center position (h, r) of the gas blowing pipe outlet 35a can be provided at a position that satisfies the following (iii) and (iv).
0.4H≦h≦0.8H (iii)
0.7R≦r≦1.5R (iv)

This central position (h, r) is more preferably provided at a position that satisfies the following (v) and (vi).
0.4H≦h≦0.6H (v)
1.4R≦r≦1.5R (vi)

Here, the height position H of the stirring blade 22 refers to the height of the central axis of the stirring blade 22 provided perpendicular to the axial direction of the stirring shaft 21, and the central axis of the stirring blade 22 is , refers to the axis represented by the line C1 in FIG. Regarding the maximum length R of the stirring blades 22 from the center of the stirring shaft 21, the center of the stirring shaft 21 means the center of the shaft represented by the line C2 in FIG. It is the length from the center of the stirring shaft 21 to the tip position of the stirring blade 22 on the axis (line C1) of the stirring blade 22 . In addition, h and The definitions of H and r and R related to the distance from the center of the stirring shaft 21 are the same in the following description, although they are not shown.

Regarding the position of the gas blowing pipe outlet 35a, if the height h is less than 0.4H (0.4H>h) or exceeds 0.8H (0.8H<h), the gas is supplied from the gas blowing pipe outlet 35a The trapped gas bubbles either miss the primary agitation zone S or travel a shorter distance. As a result, the effect of dividing air bubbles is reduced, making it difficult to obtain small-diameter air bubbles. As mentioned above, since the size of bubbles affects the rate of rise due to buoyancy, if the effect of dividing bubbles decreases, it means that the time it takes for the bubbles to reach the liquid surface is shortened. The volume of air bubbles is reduced.

Regarding the position of the gas blowing pipe outlet 35a, when the distance r between the center of the outlet and the center of the stirring shaft 21 exceeds 1.5R (1.5R<r), the agitation flow in the agitation region S where bubbles are the main Since the distance to flow in the liquid phase and reach the liquid surface is shortened, the amount of air bubbles in the liquid phase is relatively reduced. On the other hand, when the distance r is less than 0.7R (0.7R>r), the number of air bubbles in the weak clockwise flow (thin arrow Y in FIG. 2) generated under the stirrer 20 increases. It will be. Bubbles on this weak flow tend to accumulate in the lower part of the stirrer 20 (under the stirring blade 22), and since the flow velocity is slow, they are likely to coalesce and increase in diameter, so they become large bubbles and move toward the liquid surface. Flooding phenomenon tends to occur, and the amount of air bubbles in the liquid phase decreases relatively.

Further, the direction of the gas blowing pipe outlet 35a is set so as to satisfy the following conditions. That is, as shown in FIG. 5A, the gas blowing pipe outlet 35a is arranged so that the gas blowing direction D at the gas blowing pipe outlet 35a is downward in a cross section along the stirring axis. Here, "downward" means that it forms an angle of more than 0° and less than 90° with respect to the axial direction of the stirring shaft 21 and faces in the opposite direction to the liquid surface of the slurry. Further, as shown in FIG. 5B, in a cross section perpendicular to the stirring shaft 21, the gas blowing direction D at the gas blowing pipe outlet 35a is the direction away from the line C2 extending from the stirring shaft 21. As shown in FIG.

Assuming that the position and direction of the gas blowing pipe outlet 35a are as described above, even if the amount of gas supplied increases, the supplied gas will flow in a slow and small clockwise flow indicated by the thin line arrow Y in FIG. The air bubbles do not go toward the stirring shaft 21, and the flooding phenomenon can be effectively prevented.

(Second embodiment)
FIG. 6(a) is a schematic front view of the cross section of the autoclave apparatus according to the second embodiment along the axial direction of the stirring shaft, and (b) is a cross section of the same apparatus perpendicular to the stirring shaft. It is the schematic diagram which looked at the top surface.

In the autoclave apparatus 1 according to the second embodiment, as shown in FIGS. 6A and 6B, in a cross section along the axial direction of the stirring shaft 21, the gas blowing direction D of the gas blowing pipe outlet 36a is upward. The gas blowing pipe 36 is arranged so that Here, "upward" means that it has an angle of more than 0° and less than 90° with respect to the axial direction of the stirring shaft 21 and faces the direction of the liquid surface of the slurry.

If the position and direction of the gas blowing pipe outlet 36a are set as above, the gas blowing direction D from the gas blowing pipe outlet 36a and the direction X of the agitated flow are opposite to each other. easier. Further, if the central position of the gas blowing pipe outlet 36a is set to a specific range, even if the amount of gas supplied increases, the flow speed is slow and small as indicated by the thin line arrow Y in FIG. Bubbles of the supplied gas do not move toward the stirring shaft 21 . In particular, when the center position of the gas blowing pipe outlet 36a is inside the stirring region S, the gas supplied from the gas blowing pipe outlet 36a is easily mixed with the stirring flow of the stirring region S, and bubbles in the liquid phase amount can be increased.

More preferably, the central position (h, r) of the gas blowing pipe outlet 36a is provided at a position that satisfies the following (vii) and (viii).
0.45H≦h≦0.65H (vii)
1.1R≦r≦1.4R (viii)

(Third embodiment)
FIG. 7(a) is a schematic front view of a cross section of the autoclave apparatus according to the third embodiment along the axial direction of the stirring shaft, and FIG. 7(b) is a cross section of the same apparatus perpendicular to the stirring shaft. It is the schematic diagram which looked at the top surface.

In the autoclave apparatus 1 according to the third embodiment, as shown in FIGS. 7A and 7B, in the cross section along the axial direction of the stirring shaft 21, the position of the outlet center of the gas blowing pipe outlet 37a is the stirring point. A gas blowing pipe 37 is arranged away from the axis 21 (r increases). In this point, the autoclave apparatus 1 according to the third embodiment differs from the autoclave apparatus 1 according to the second embodiment.

As described above, if the position and direction of the gas blowing pipe outlet 37a are set as above, the gas blowing direction D from the gas blowing pipe outlet 37a and the direction X of the agitated flow are opposite to each other. It becomes easy to divide and reduce the diameter. Further, if the central position of the gas blowing pipe outlet 37a is set within a specific range, even if the amount of gas supplied increases, the flow speed is slow and small as indicated by the thin line arrow Y in FIG. Bubbles of the supplied gas do not move toward the stirring shaft 21 . In particular, when the center position of the gas blowing pipe outlet 37a is near the outside of the stirring area S, the flooding phenomenon can be effectively prevented. Furthermore, if the central position of the gas injection pipe outlet 37a is set to a position that satisfies the formulas (vii) and (viii), the flooding phenomenon can be effectively prevented and the amount of air bubbles in the liquid phase can be increased. can.

As described above, in any of the first to third embodiments, according to the autoclave apparatus 1 in which the positions of the gas blowing pipe outlets 35a, 36a, and 37a are arranged at specific positions, Gas bubbles can be efficiently divided into small bubble diameters, and the amount of bubbles present in the liquid phase can be increased. Further, according to the autoclave apparatus 1 in which the gas blowing pipe outlets 35a, 36a, 37a are directed in a specific direction, even if the gas supply amount increases, the time for the bubbles to flow in the main stirring area S becomes longer, and the stirrer Since it is difficult for the gas to accumulate in the lower part of 20, the flooding phenomenon is less likely to occur, and the gas supply amount can be easily increased. In addition, by performing a leaching process or the like for leaching valuable metals contained in the solid matter in the slurry using such an autoclave apparatus 1, the reaction efficiency can be improved by increasing the amount of bubbles in the liquid phase or increasing the amount of gas supplied. is increased, and the valuable metal can be effectively leached into the liquid.

In the present embodiment, as described above, the gas blowing pipe outlets 35a, 36a, 37a are arranged at specific positions and directions, so that the agitated flow generated by the stirrer 20 efficiently divides the air bubbles. It is possible to reduce the diameter by increasing the pressure, and the flooding phenomenon is less likely to occur even if the amount of gas supplied increases. Therefore, it is not necessary to reduce the pipe diameters and outlet diameters of the gas blowing pipes 35, 36, 37 by a predetermined ratio, and pressure loss can be suppressed. Therefore, the outlet diameters of the gas injection tubes 35, 36, and 37 are not particularly limited, and are appropriately adjusted according to the value obtained by dividing the flow rate of the gas under pressure required for the reaction by the outlet area (outlet flow velocity). do it.

Among them, however, in an industrial-scale reactor of, for example, about 5 m ³ , the outlet diameter of the gas injection pipes 35, 36, 37 is preferably 10 mm to 150 mm. If the outlet diameter of the gas blowing pipes 35, 36, 37 is less than 10 mm, the pressure loss may increase at a required air flow rate (for example, 300 Nm ³ /h) or more, and the cost of pressurizing the gas to be blown is increased. In addition to the reaction product and residue after the reaction, the outlet may be clogged. Further, if the outlet diameter of the gas blowing pipes 35, 36, 37 exceeds 150 mm, the pipes themselves may change the flow of the stirring flow.

EXAMPLES The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples.

(Experimental example 1)
In one compartment of the autoclave apparatus, oxygen is supplied by blowing air while stirring a slurry obtained by adding a mixed sulfide (solid) containing nickel and cobalt, which is a liquid phase, to sulfuric acid, thereby supplying oxygen to the slurry. A high-temperature pressure leaching process was performed to extract the valuable metals contained in the solid matter. Specifically, as shown in the schematic diagrams of FIGS. 4 and 5, an autoclave apparatus equipped with a stirrer and a gas blowing pipe is used, and the outlet position of the gas blowing pipe is arranged at a predetermined position. Using. Here, the gas blowing pipe used had an outlet diameter of 62.3 mm. In addition, the temperature in the hot pressurized leaching was set at 160° C., and the pressure of the autoclave apparatus was set at 16 atmospheres.

In this process, a population balance equation that takes into account coalescence and splitting in the dispersed phase is used in the Eulerian-Eulerian coordinate system to model a multiphase flow of continuous and dispersed phases, and the volume fraction of bubbles in the liquid phase is calculated. The fraction was analyzed and the total amount of air in the liquid phase was calculated from the integral within that compartment. In this model, the continuous phase is a slurry of the liquid phase and the dispersed phase is bubbles (air).

The boundary conditions were as follows.
Density of slurry as continuous phase: 1275 kg/m ³
Density of air as dispersed phase: 11 kg/m ³
Bubble diameter immediately after being released from the air blowing surface in the gas blowing pipe: 5 mm
Stirring rotation speed: 159 rpm

Also, the relative air blowing amount was set to 0.157 min ⁻¹ . Here, the relative air blowing amount is the ratio of the air (dispersed phase) blowing amount (m ³ /min) to the slurry (continuous phase) amount (m ³ ) accommodated in the compartment.

In Experimental Example 1, as shown in FIG. 5, the gas blowing was provided downward so as to face the direction away from the stirring shaft 21 and form an angle of 45° with the plane perpendicular to the stirring shaft 21. A tube 35 was used to supply gas. Here, for gas supply, the center position of the gas blowing pipe outlet 35a is h from the position where the extension of the stirring shaft intersects the inner wall of the compartment, and r is the distance from the center of the stirring shaft. Occasionally, a device with (h, r) = (0.44H, 1.48R) was used.

(Experimental examples 2 and 3)
The center position (h, r) of the gas injection pipe outlet 35a is (h, r) = (0.44H, 1.32R) in Experimental Example 2, and (h, r) = (0.31H, 1.17R), and treated in the same manner as in Experimental Example 1. Here, the angle between the gas blowing pipe 35 and the plane perpendicular to the stirring shaft 21 was set to 45° as in Experimental Example 1.

(Experimental Examples 4-9)
In Experimental Examples 4 to 9, as shown in FIGS. 6 and 7, the gas was directed away from the stirring shaft 21 and formed an angle of 45° with the plane perpendicular to the stirring shaft 21. A gas was supplied using a gas blowing pipe 36 or a gas blowing pipe 37 provided downward. Here, for gas supply, the center position (h, r) of the gas blowing pipe outlet 36a or the gas blowing pipe outlet 37a is (h, r) = (0.53H, 1.27R) in Experimental Example 4. (h, r) = (0.62H, 1.19R) in Experimental Example 5, (h, r) = (0.62H, 1.38R) in Experimental Example 6, and (h, r) = in Experimental Example 7 (0.62H, 0.91R), (h, r) = (0.66H, 0.78R) in Experimental Example 8, and (h, r) = (0.33H, 0.52R) in Experimental Example 9. A device was used.

Table 1 summarizes the relative values of the amount of air in the liquid and the stirring power of the stirrer for Experimental Examples 1 to 9. Here, the relative value of the stirring power is the value of _Pg / _P0 , where P0 is the stirring power of the stirrer when air is not blown, and _Pg is the stirring power of the stirrer when air _is blown.

As can be seen from the results in Table 1, in the pressurized reactors of Experimental Examples 1, 2, and 4 to 8, the height h of the outlet center of the gas injection pipe was set to the height of the stirring blade. When the height H was 0.40 times or more and 0.80 times or less, the amount of air in the liquid was 0.040 m ³ or more, and the amount of gas dissolved in the liquid increased. In particular, in the pressurized reactors of Experimental Examples 4 to 7, the outlet of the gas injection pipe is directed upward, and the height h of the center of the outlet of the gas injection pipe is set to the height of the stirring blade. When the ratio was 0.65 times or more, the amount of air in the liquid was 0.044 m ³ or more, and the amount of gas dissolved in the liquid increased. On the other hand, in the pressurized reactors of Experimental Examples 3 and 9, the height h of the outlet center of the gas injection pipe was 0.40 times or more the height H to the height position of the stirring blade and 0.80. When it was doubled or less, the amount of air in the liquid decreased to less than 0.040 m ³ . The reason why the amount of air in the liquid is small is that the bubbles supplied from the gas blowing pipe are out of the main stirring area S, and the distance that the air bubbles flow in the main stirring area S is short. .

In addition, in the pressurized reactors of Experimental Examples 1 to 8, the distance r from the center of the stirring shaft to the center of the outlet of the gas injection pipe was 1.00 times or more the maximum length R of the stirring blade from the center of the stirring shaft. , the stirring relative power value was 0.40 or more, and the flooding phenomenon hardly occurred. In particular, in the pressurized reactor of Experimental Example 1, the outlet of the gas injection pipe was directed downward, and the distance r from the center of the stirring shaft to the center of the outlet of the gas injection pipe was set to the maximum of the stirring blade from the center of the stirring shaft. When the length R was 1.40 times or more, the stirring relative power value was 0.50 or more, and the flooding phenomenon was more difficult to occur. In addition, in the pressurized reactors of Experimental Examples 4 to 6, the outlet of the gas injection pipe was directed upward, and the distance r from the center of the stirring shaft to the center of the outlet of the gas injection pipe was set to When the maximum length R was set to 1.10 times or more, the stirring relative power value became 0.50 or more, and the flooding phenomenon became more difficult to occur. On the other hand, in the pressurized reactor of Experimental Example 9, the distance r from the center of the stirring shaft to the center of the outlet of the gas injection pipe was 0.52 times the maximum length R of the stirring blade from the center of the stirring shaft. When the stirring relative power value was less than 0.40, air bubbles tended to accumulate in the lower portion of the stirrer, and a flooding phenomenon was likely to occur. That is, in the pressurized reactor, the occurrence of the flooding phenomenon can be suppressed by setting the ratio of the distance r to the outlet center of the gas injection pipe to the maximum length R of the stirring blade within a specific range. rice field.

Among the above pressurized reactors, in particular, in the pressurized reactors of Experimental Examples 1 and 4 to 6, the amount of air in the liquid is 0.05 m ³ or more, and the relative stirring power value is 0.50 or more. Therefore, it is considered that the outlet center of the gas blowing pipe is arranged at a particularly good position.

1 autoclave device 1w inner wall surface of autoclave device 10, 10A to 10E compartment 20, 20A to 20E stirrer 21 stirring shaft 22 stirring blade 35, 36, 37 gas blowing pipe 35a, 36a, 37a gas blowing pipe outlet

Claims (8)

A pressurized reactor comprising a stirrer and a gas-injecting pipe, wherein a cylindrical container is installed horizontally, and a slurry is contained in the container as a liquid phase,
The stirrer has a stirring shaft suspended from the top of the pressurized reactor, and a stirring blade that is provided perpendicular to the stirring shaft and generates a downward flow of the liquid phase,
When the pressurized reaction device is viewed from the front in a cross section along the axial direction of the stirring shaft,
Let H be the height from the position where the line extending from the stirring shaft intersects the inner wall of the pressurized reactor to the height position of the stirring blade, and R be the maximum length of the stirring blade from the center of the stirring shaft. When
The outlet center of the gas blowing pipe is
Provided at a position that satisfies the following formula, where h is the height from the position where the line extending from the stirring shaft intersects the inner wall of the pressurized reactor, and r is the distance from the center of the stirring shaft. ,
The outlet of the gas blowing pipe is
The gas blowing direction at the outlet is arranged in a direction away from a line extending from the stirring shaft and in a downward direction or an upward direction.
Pressurized reactor.
0.5H≦h≦0.8H
0.7R≤r≤1.3R A pressurized reactor comprising a stirrer and a gas-injecting pipe, wherein a cylindrical container is installed horizontally, and a slurry is contained in the container as a liquid phase,
The stirrer has a stirring shaft suspended from the top of the pressurized reactor, and a stirring blade that is provided perpendicular to the stirring shaft and generates a downward flow of the liquid phase,
When the pressurized reaction device is viewed from the front in a cross section along the axial direction of the stirring shaft,
Let H be the height from the position where the line extending from the stirring shaft intersects the inner wall of the pressurized reactor to the height position of the stirring blade, and R be the maximum length of the stirring blade from the center of the stirring shaft. When
The outlet center of the gas blowing pipe is
Provided at a position that satisfies the following formula, where h is the height from the position where the line extending from the stirring shaft intersects the inner wall of the pressurized reactor, and r is the distance from the center of the stirring shaft. ,
The outlet of the gas blowing pipe is
The gas blowing direction at the outlet is arranged in a direction away from a line extending from the stirring shaft and in a downward direction or an upward direction.
Pressurized reactor.
0.4H≦h≦0.8H
0.7R≤r≤1.5R The outlet center of the gas blowing pipe is provided at a position that satisfies the following formula,
The outlet of the gas blowing pipe is arranged so that the gas blowing direction at the outlet is in a direction away from a line extending from the stirring shaft and downward.
A pressurized reactor according to claim 2.
0.4H≦h≦0.6H
1.4R≤r≤1.5R The outlet center of the gas blowing pipe is provided at a position that satisfies the following formula,
The outlet of the gas blowing pipe is arranged such that the gas blowing direction at the outlet is in a direction away from a line extending from the stirring shaft and upward.
A pressurized reactor according to claim 2.
0.45H≦h≦0.65H
1.1R≤r≤1.4R The pressurized reaction apparatus according to any one of claims 1 to 4, wherein the outlet diameter of the gas injection pipe is 10 mm to 150 mm. 6. The pressurized reaction apparatus according to any one of claims 1 to 5, which is an autoclave apparatus. 7. The pressurized reactor according to any one of claims 1 to 6, which is used for leaching a slurry containing mixed sulfides of nickel and cobalt by adding an acid under high temperature and pressure. A method for leaching valuable metals, comprising leaching valuable metals from solids contained in a slurry using the pressurized reactor according to any one of claims 1 to 7.

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