Continuous leaching device

Abstract

The utility model discloses a continuous leaching device, and belongs to the technical field of hydrometallurgy. The continuous leaching device comprises a first conveying pipe and at least two reaction containers. The reaction containers are arranged on one side of the first conveying pipe at intervals in the axial direction of the first conveying pipe, each reaction container is provided with a feeding pipe, a discharging pipe and a compressed air pipe, the feeding pipe is communicated with the first conveying pipe and a feeding port of the reaction container, the discharging pipe is communicated with a discharging port of the reaction container and the first conveying pipe, and the compressed air pipe is communicated with the first conveying pipe. A first partition piece is arranged on the feeding pipe, and a second partition piece is arranged on the discharging pipe; third partition pieces are arranged on the first conveying pipe, third partition pieces are arranged between the communicating position of the feeding pipe of each reaction container and the first conveying pipe and the communicating position of the discharging pipe of each reaction container and the first conveying pipe, the compressed air pipe is arranged in the reaction container, and an air outlet of the compressed air pipe is located in the bottom of the reaction container. According to the continuous leaching device provided by the invention, the production efficiency is effectively improved.

Description

Technical Field

[0001] The present application relates to the technical field of hydrometallurgy, and in particular to a continuous leaching device. Background Art

[0002] Hydrometallurgy is a method of bringing ores, concentrates enriched by beneficiation or other raw materials into contact with aqueous solutions or other liquids, and then transferring the useful metals contained in the raw materials into the liquid phase through chemical reactions, and then separating and enriching the various useful metals contained in the liquid phase, and finally recovering them in the form of metals or other compounds. It mainly includes unit operations such as leaching, liquid-solid separation, solution purification, metal extraction from solution and wastewater treatment.

[0003] At present, the continuous leaching device in the prior art usually includes a plurality of leaching tanks, which are connected in series through pipelines. However, in this way, when one of the leaching tanks fails and needs to be repaired, the entire continuous leaching device must be stopped to meet the maintenance conditions, which is not conducive to the continuity of production and reduces production efficiency. In addition, due to the slow stirring speed, the unreacted materials in the leaching tank are easily deposited at the bottom of the tank and cannot be discharged through the overflow device, and the thickening of the slag layer at the bottom of the tank will affect the stirring and normal production, so it is necessary to stop production and clean the slag layer, which further reduces production efficiency. Utility Model Content

[0004] In view of this, the purpose of the present application is to overcome the deficiencies in the prior art and to provide a continuous leaching device to solve the technical problem of low production efficiency of the continuous leaching device in the prior art.

[0005] To solve the above technical problems, this application provides:

[0006] A continuous leaching device, comprising:

[0007] a first delivery pipe;

[0008] At least two reaction containers, the reaction containers are arranged at intervals on one side of the first conveying pipe along the axial direction of the first conveying pipe, each of the reaction containers is provided with a feed pipe, a discharge pipe and a compressed air pipe, the feed pipe is respectively connected with the first conveying pipe and the feed port of the reaction container, the discharge pipe is respectively connected with the discharge port of the reaction container and the first conveying pipe, the feed pipe is provided with a first partition, and the discharge pipe is provided with a second partition;

[0009] A third partition is provided on the first conveying pipe, and the third partition is provided between the connecting position between the feed pipe and the first conveying pipe and the connecting position between the discharge pipe and the first conveying pipe of each reaction container. The compressed air pipe is arranged in the reaction container, and the air outlet of the compressed air pipe is located at the bottom of the reaction container.

[0010] In addition, the continuous leaching device according to the present application may also have the following additional technical features:

[0011] In some embodiments of the present application, the continuous leaching device also includes a batching container, a second delivery pipe and a buffer container, the second delivery pipe is connected to the batching container and the buffer container respectively, and one end of the first delivery pipe close to the second delivery pipe is connected to one end of the buffer container away from the second delivery pipe.

[0012] In some embodiments of the present application, the continuous leaching device further includes a first pump body, the buffer container is located above the batching container, and the first pump body is disposed on the second delivery pipe.

[0013] In some embodiments of the present application, along the first direction, the heights of the reaction container and the first delivery pipe gradually decrease.

[0014] In some embodiments of the present application, the reaction container includes a main body portion and a base portion, the main body portion is disposed on the base portion, and along the first direction, the height of the base portion gradually decreases.

[0015] In some embodiments of the present application, the height difference between two adjacent base portions is 10 cm to 15 cm.

[0016] In some embodiments of the present application, at least two compressed air pipes are provided, and the compressed air pipes are arranged at intervals along the inner circumference of the reaction container.

[0017] In some embodiments of the present application, the reaction container is provided with a second pump body, and the second pump body is connected to the compressed air pipe.

[0018] In some embodiments of the present application, the continuous leaching device also includes a liquid storage container, the reaction container is provided with a liquid adding tube and a third pump body, the liquid adding tube is respectively connected to the liquid adding ports of the liquid storage container and the reaction container, and the third pump body is arranged on the liquid adding tube.

[0019] In some embodiments of the present application, the reaction container is also provided with a stirring mechanism, which includes a driving member, a stirring shaft and at least two blades. The output end of the driving member is connected to the stirring shaft for driving the stirring shaft to rotate. The stirring shaft is located in the reaction container, and the blades are arranged at intervals along the circumference of the stirring shaft.

[0020] Compared with the prior art, the beneficial effects of this application are:

[0021] The present application proposes a continuous leaching device. When all reaction vessels are working, all first partitions and second partitions are opened, and all third partitions are closed, so that the reaction vessels are connected in series, thereby continuously leaching the feed liquid. When one of the reaction vessels needs to be repaired, the first partition and the second partition of the reaction vessel are closed, and the third partition corresponding to the reaction vessel is opened, so that the feed liquid bypasses the reaction vessel and flows into the next reaction vessel or the next process through the first delivery pipe, thereby effectively isolating the reaction vessel from the entire series reaction vessel system, and the reaction vessel can be repaired without stopping the production of the entire continuous leaching device, thereby ensuring the continuous production and improving the production efficiency.

[0022] At the same time, by arranging a compressed air pipe in each reaction vessel, and the air outlet of the compressed air pipe is located at the bottom of the reaction vessel, the compressed air blown out of the compressed air pipe when the reaction vessel is working can blow away the unreacted material in the reaction vessel, so that the material can rotate with the stirring vortex and be discharged through the discharge pipe through the overflow device, thereby effectively avoiding the deposition of the material at the bottom of the reaction vessel, thereby reducing the probability of stopping production to clean the slag layer, and further improving production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0024] Figure 1 A schematic top view of a continuous leaching device in some embodiments of the present application is shown;

[0025] Figure 2 The front view of the reaction container in some embodiments of the present application is shown. Figure 1 ;

[0026] Figure 3 A schematic top view of a reaction container in some embodiments of the present application is shown;

[0027] Figure 4 A schematic front view of a second delivery pipe, a buffer container, and a first delivery pipe in some embodiments of the present application is shown;

[0028] Figure 5 The front view of the reaction container in some embodiments of the present application is shown. Figure 2 .

[0029] Description of main component symbols:

[0030] 100-continuous leaching device; 110-first delivery pipe; 111-third partition; 120-reaction container; 121-feed pipe; 1211-first partition; 122-discharge pipe; 1221-second partition; 123-compressed air pipe; 124-main body; 125-base; 126-second pump body; 127-liquid adding pipe; 128-third pump body; 129-stirring mechanism; 1291-driving member; 1292-stirring shaft; 1293-blades; 130-second delivery pipe; 140-buffer container; 150-first pump body. DETAILED DESCRIPTION

[0031] The embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and cannot be understood as limiting the present application.

[0032] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0033] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0034] In this application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0035] In the present application, unless otherwise clearly specified and limited, a first feature being “above” or “below” a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being “above”, “above”, and “above” a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being “below”, “below”, and “below” a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0036] like Figure 1 , Figure 2 and Figure 3 As shown, an embodiment of the present application provides a continuous leaching device 100. The continuous leaching device 100 includes a first transport pipe 110 and at least two reaction containers 120.

[0037] Among them, the reaction container 120 is arranged at a distance on one side of the first conveying pipe 110 along the axial direction of the first conveying pipe 110, and each of the reaction containers 120 is provided with a feed pipe 121, a discharge pipe 122 and a compressed air pipe 123. The feed pipe 121 is respectively connected with the first conveying pipe 110 and the feed port of the reaction container 120, and the discharge pipe 122 is respectively connected with the discharge port of the reaction container 120 and the first conveying pipe 110. A first partition piece 1211 is provided on the feed pipe 121, and a second partition piece 1221 is provided on the discharge pipe 122.

[0038] A third partition piece 111 is provided on the first conveying pipe 110, and the third partition piece 111 is provided between the connecting position between the feed pipe 121 and the first conveying pipe 110 and the connecting position between the discharge pipe 122 and the first conveying pipe 110 of each reaction container 120. The compressed air pipe 123 is provided in the reaction container 120, and the air outlet of the compressed air pipe 123 is located at the bottom of the reaction container 120.

[0039] The continuous leaching device 100 provided in the embodiment of the present application is configured by setting at least two reaction containers 120, and the reaction containers 120 are spaced apart on one side of the first conveying pipe 110 along the axial direction of the first conveying pipe 110, and each reaction container 120 is provided with a feed pipe 121 and a discharge pipe 122, the feed pipe 121 is respectively connected with the first conveying pipe 110 and the feed port of the reaction container 120, the discharge pipe 122 is respectively connected with the discharge port of the reaction container 120 and the first conveying pipe 110, and a first partition member 1211, a second partition member 1221 and a third partition member 111 are respectively provided on the feed pipe 121, the discharge pipe 122 and the first conveying pipe 110, and a third partition member 111 is provided between the connecting position between the feed pipe 121 of each reaction container 120 and the first conveying pipe 110 and the connecting position between the discharge pipe 122 and the first conveying pipe 110.

[0040] In this way, when all the reaction vessels 120 are working, all the first partition members 1211 and the second partition members 1221 are opened, and all the third partition members 111 are closed, so that the reaction vessels 120 are connected in series with each other, so as to continuously leach the feed liquid. When one of the reaction vessels 120 needs to be repaired, the first partition member 1211 and the second partition member 1221 of the reaction vessel 120 are closed, and the third partition member 111 corresponding to the reaction vessel 120 is opened, so that the feed liquid bypasses the reaction vessel 120 and flows into the next reaction vessel 120 or the next process through the first conveying pipe 110, thereby effectively isolating the reaction vessel 120 from the entire series reaction vessel 120 system, and the reaction vessel 120 can be repaired without stopping the production of the entire continuous leaching device 100, thereby ensuring the continuous production and improving the production efficiency.

[0041] At the same time, by arranging a compressed air pipe 123 in each reaction vessel 120, and the air outlet of the compressed air pipe 123 is located at the bottom of the reaction vessel 120, when the reaction vessel 120 is working, the compressed air blown out by the compressed air pipe 123 can blow away the unreacted material in the reaction vessel 120, so that the material can rotate with the stirring vortex and be discharged through the discharge pipe 122 through the overflow device, thereby effectively avoiding the deposition of the material at the bottom of the reaction vessel 120, thereby reducing the probability of stopping production to clean the slag layer, and further improving production efficiency.

[0042] Exemplarily, the first partition piece 1211 , the second partition piece 1221 and the third partition piece 111 may all be knife gate valves.

[0043] like Figure 1 and Figure 4As shown, in one embodiment of the present application, the continuous leaching device 100 also includes a batching container, a second delivery pipe 130 and a buffer container 140, the second delivery pipe 130 is connected to the batching container and the buffer container 140 respectively, and one end of the first delivery pipe 110 close to the second delivery pipe 130 is connected to one end of the buffer container 140 away from the second delivery pipe 130.

[0044] In this embodiment, the second delivery pipe 130 is connected to the ingredient container and the buffer container 140 respectively, and the end of the first delivery pipe 110 close to the second delivery pipe 130 is connected to the end of the buffer container 140 away from the second delivery pipe 130, so that the material liquid in the ingredient container is first transported to the buffer container 140 through the second delivery pipe 130, and then flows into the first delivery pipe 110 after buffering in the buffer container 140. The buffer container 140 plays a role in reducing the impact force, thereby effectively ensuring the stability and reliability of the use of the first delivery pipe 110, thereby reducing the probability of stopping production for repairing the first delivery pipe 110, ensuring the continuous production, and further improving the production efficiency.

[0045] like Figure 4 As shown, in the above embodiment of the present application, the continuous leaching device 100 further includes a first pump body 150 , the buffer container 140 is located above the batching container, and the first pump body 150 is disposed on the second delivery pipe 130 .

[0046] In this embodiment, the buffer container 140 is located above the ingredient container, and the first pump body 150 is arranged on the second delivery pipe 130, so that the material liquid in the ingredient container is automatically delivered to the buffer container 140 through the second delivery pipe 130 under the pumping action of the first pump body 150, and then delivered to the first delivery pipe 110 after buffering in the buffer container 140.

[0047] Illustratively, the first pump body 150 may be a water pump.

[0048] like Figure 5 As shown, in one embodiment of the present application, along the first direction, the heights of the reaction container 120 and the first delivery pipe 110 gradually decrease.

[0049] In this embodiment, by setting the reaction container 120 and the first conveying pipe 110 to gradually decrease in height along the first direction, the slurry can automatically flow from the upper reaction container 120 to the next reaction container 120 under the action of its own gravitational potential energy, thereby saving energy consumption required for production and reducing production costs.

[0050] It should be noted that the first direction corresponds to Figure 5 The X direction in .

[0051] like Figure 5 As shown, in the above embodiment of the present application, the reaction container 120 includes a body portion 124 and a base portion 125, the body portion 124 is disposed on the base portion 125, and along the first direction, the height of the base portion 125 gradually decreases.

[0052] In this embodiment, the base portion 125 is arranged on the ground, and the main body portion 124 is arranged on the base portion 125. The height of the base portion 125 is gradually lowered by setting it along the first direction, so that the height of the main body portion 124 of the next reaction container 120 is lower than the height of the main body portion 124 of the previous reaction container 120, so that the feed liquid can automatically flow from the main body portion 124 of the previous reaction container 120 to the main body portion 124 of the next reaction container 120 under the action of the gravitational potential energy difference, effectively saving the energy consumption required for production and reducing the production cost.

[0053] In the above embodiment of the present application, the height difference between two adjacent base parts 125 is 10 cm to 15 cm.

[0054] In this embodiment, by controlling the height difference between two adjacent base parts 125 to be between 10 cm and 15 cm, on the one hand, it is possible to avoid the technical problem that the height difference between the base parts 125 of two adjacent reaction containers 120 is too small, so that the gravitational potential energy difference between the body parts 124 of the two adjacent reaction containers 120 is too small, which affects the automatic flow of the feed liquid from the body part 124 of the previous reaction container 120 to the body part 124 of the next reaction container 120. On the other hand, it is also possible to avoid the technical problem that the height difference between the base parts 125 of two adjacent reaction containers 120 is too large, which affects the installation of pipelines and increases material costs.

[0055] Exemplarily, the height difference between two adjacent base portions 125 may be 10 cm, 11 cm, 12 cm, 13 cm, 14 cm, 15 cm, etc., and may be specifically designed according to actual needs of the device, which will not be described one by one here.

[0056] like Figure 2 and Figure 3 As shown, in one embodiment of the present application, at least two compressed air pipes 123 are provided, and the compressed air pipes 123 are arranged at intervals along the inner circumference of the reaction container 120 .

[0057] In this embodiment, by setting the number of compressed air pipes 123 to at least two and arranging the compressed air pipes 123 at intervals along the inner circumference of the reaction vessel 120, the blowing area at the bottom of the reaction vessel 120 can be effectively increased, thereby improving the blowing effect on the material, making it difficult for unreacted materials to deposit at the bottom of the reaction vessel 120, further reducing the probability of needing to stop production to clean the slag layer, and further improving production efficiency.

[0058] like Figure 2 As shown, in one embodiment of the present application, the reaction container 120 is provided with a second pump body 126 , and the second pump body 126 is connected to the compressed air pipe 123 .

[0059] In this embodiment, a second pump body 126 connected to the compressed air pipe 123 is provided so that the compressed air generated by the second pump body 126 can be blown out toward the bottom of the reaction container 120 through the compressed air pipe 123 to disperse the unreacted material in the reaction container 120 and prevent the material from being deposited at the bottom of the reaction container 120.

[0060] Illustratively, the second pump body 126 may be a vacuum pump.

[0061] like Figure 2 and Figure 3 As shown, in one embodiment of the present application, the continuous leaching device 100 also includes a liquid storage container, the reaction container 120 is provided with a liquid adding pipe 127 and a third pump body 128, the liquid adding pipe 127 is respectively connected to the liquid adding ports of the liquid storage container and the reaction container 120, and the third pump body 128 is arranged on the liquid adding pipe 127.

[0062] In this embodiment, the liquid adding pipe 127 is connected to the liquid adding ports of the liquid storage container and the reaction container 120 respectively, and the third pump body 128 is arranged on the liquid adding pipe 127, so that the acidic solution in the liquid storage container is automatically transported to the reaction container 120 through the liquid adding pipe 127 under the pumping action of the third pump body 128 to react chemically with the material in the reaction container 120, thereby transferring the useful metals contained in the material into the liquid phase.

[0063] For example, the third pump body 128 may be a water pump, and the acidic solution may be sulfuric acid.

[0064] like Figure 1As shown, in any of the above embodiments of the present application, the reaction vessel 120 is further provided with a stirring mechanism 129, and the stirring mechanism 129 includes a driving member 1291, a stirring shaft 1292 and at least two blades 1293, and the output end of the driving member 1291 is connected to the stirring shaft 1292 for driving the stirring shaft 1292 to rotate, the stirring shaft 1292 is located in the reaction vessel 120, and the blades 1293 are arranged at intervals along the circumference of the stirring shaft 1292.

[0065] In this embodiment, the output end of the driving member 1291 is connected to the stirring shaft 1292 located in the reaction vessel 120 to drive the stirring shaft 1292 to rotate automatically, thereby driving the blades 1293 arranged at circumferential intervals along the stirring shaft 1292 to rotate synchronously and automatically, and then the slurry and the acid solution in the reaction vessel 120 are stirred under the rotation of the blades 1293, so that the slurry and the acid solution are mixed more quickly and evenly, thereby accelerating the progress of the chemical reaction and effectively improving the leaching efficiency.

[0066] Exemplarily, the driving member 1291 may be a motor.

[0067] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0068] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations on the present application. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present application.

Claims

1. A continuous leaching device, characterized in that: include: A first delivery pipe (110); at least two reaction containers (120), the reaction containers (120) being arranged at intervals on one side of the first conveying pipe (110) along the axial direction of the first conveying pipe (110), each of the reaction containers (120) being provided with a feed pipe (121), a discharge pipe (122) and a compressed air pipe (123), the feed pipe (121) being respectively connected to the first conveying pipe (110) and the feed port of the reaction container (120), the discharge pipe (122) being respectively connected to the discharge port of the reaction container (120) and the first conveying pipe (110), the feed pipe (121) being provided with a first partition member (1211), and the discharge pipe (122) being provided with a second partition member (1221); A third partition member (111) is provided on the first conveying pipe (110), and the third partition member (111) is provided between the connecting position between the feed pipe (121) and the first conveying pipe (110) and the connecting position between the discharge pipe (122) and the first conveying pipe (110) of each reaction container (120). The compressed air pipe (123) is provided in the reaction container (120), and the air outlet of the compressed air pipe (123) is located at the bottom of the reaction container (120).

2. The continuous leaching device according to claim 1, characterized in that: The continuous leaching device (100) further comprises a batching container, a second delivery pipe (130) and a buffer container (140), wherein the second delivery pipe (130) is respectively connected to the batching container and the buffer container (140), and an end of the first delivery pipe (110) close to the second delivery pipe (130) is connected to an end of the buffer container (140) away from the second delivery pipe (130).

3. The continuous leaching device according to claim 2, characterized in that: The continuous leaching device (100) further comprises a first pump body (150), the buffer container (140) is located above the batching container, and the first pump body (150) is arranged on the second conveying pipe (130).

4. The continuous leaching device according to claim 1, characterized in that: Along the first direction (X), the heights of the reaction container (120) and the first delivery pipe (110) gradually decrease.

5. The continuous leaching device according to claim 4, characterized in that: The reaction container (120) comprises a main body (124) and a base (125), wherein the main body (124) is disposed on the base (125), and along the first direction (X), the height of the base (125) gradually decreases.

6. The continuous leaching device according to claim 5, characterized in that: The height difference between two adjacent base parts (125) is 10 cm to 15 cm.

7. The continuous leaching device according to claim 1, characterized in that: At least two compressed air pipes (123) are provided, and the compressed air pipes (123) are arranged at intervals along the inner circumference of the reaction container (120).

8. The continuous leaching device according to claim 1, characterized in that: The reaction container (120) is provided with a second pump body (126), and the second pump body (126) is connected to the compressed air pipe (123).

9. The continuous leaching device according to claim 1, characterized in that: The continuous leaching device (100) further comprises a liquid storage container, the reaction container (120) is provided with a liquid adding pipe (127) and a third pump body (128), the liquid adding pipe (127) is respectively connected to the liquid adding ports of the liquid storage container and the reaction container (120), and the third pump body (128) is arranged on the liquid adding pipe (127).

10. The continuous leaching device according to any one of claims 1 to 9, characterized in that: The reaction container (120) is further provided with a stirring mechanism (129), and the stirring mechanism (129) includes a driving member (1291), a stirring shaft (1292) and at least two blades (1293). The output end of the driving member (1291) is connected to the stirring shaft (1292) for driving the stirring shaft (1292) to rotate. The stirring shaft (1292) is located in the reaction container (120), and the blades (1293) are arranged at intervals along the circumference of the stirring shaft (1292).

Images