Ammonium metavanadate filtrate and vanadium slag roasting clinker leaching synergistic treatment system

Abstract

This utility model relates to the field of vanadium extraction from vanadium slag, specifically to a co-processing system for leaching ammonium metavanadate filtrate and vanadium slag roasted clinker. The system includes: a centrifugal filtration device, whose input end receives the ammonium metavanadate precipitate underflow and is configured to filter the underflow to obtain ammonium metavanadate filtrate; a solid-liquid separation device, whose input end is connected to the output end of the centrifugal filtration device and is configured to perform solid-liquid separation on the ammonium metavanadate filtrate to obtain a clear ammonium metavanadate solution; and a leaching device, whose input end is connected to the output end of the solid-liquid separation device and is configured to receive vanadium slag roasted clinker and the clear ammonium metavanadate solution for leaching to obtain vanadium leachate. This utility model reduces wastewater generation while increasing the yield of ammonium metavanadate, reuses the clear filtrate from the washings, reduces water consumption, and lowers wastewater treatment costs.

Description

Technical Field

[0001] This utility model relates to the field of vanadium extraction from vanadium slag, specifically to a co-processing system for leaching ammonium metavanadate filtrate and vanadium slag roasted clinker. Background Technology

[0002] Ammonium metavanadate, as a key vanadate, plays an indispensable role in many industrial fields, especially as an important intermediate product in the production of energy storage-grade vanadium pentoxide. In industrial production, the mainstream method for preparing ammonium metavanadate is the vanadium solution acidic ammonium salt precipitation method, followed by further purification of the precipitate by adding alkali. This process is relatively mature technically and can produce ammonium metavanadate on a large scale to meet basic market demand. However, this process has also revealed some problems in actual operation. After separation from the precipitate residue, the resulting ammonium metavanadate product often contains high levels of impurities such as sodium and sulfur. The presence of these impurities seriously affects the purity of ammonium metavanadate, thereby reducing the performance of energy storage-grade vanadium pentoxide produced from it.

[0003] To remove these impurities and improve the purity of ammonium metavanadate, industrial processes typically involve washing it with large amounts of pure water. The wash water and residual precipitate from washing the ammonium metavanadate are then mixed and directly fed into the wastewater treatment system. A large amount of pure water is consumed during the washing process, and the washed water is not effectively recycled or reused, resulting in extremely low water resource utilization efficiency. Furthermore, the mixing of wash water and residual precipitate before entering the wastewater treatment system significantly increases the wastewater volume, raising the difficulty and cost of treatment. Utility Model Content

[0004] To address the shortcomings of existing technologies, this invention proposes a synergistic treatment system for ammonium metavanadate filtrate and vanadium slag roasting clinker leaching, which can recover residual vanadium in the washing filtrate, improve water resource utilization efficiency, and reduce wastewater treatment costs.

[0005] This utility model provides a synergistic treatment system for leaching ammonium metavanadate filtrate and vanadium slag roasted clinker, comprising: A centrifugal filtration device, wherein the input end of the centrifugal filtration device receives the ammonium metavanadate precipitate underflow and is configured to filter the ammonium metavanadate precipitate underflow to obtain ammonium metavanadate filtrate; A solid-liquid separation device, wherein the input end of the solid-liquid separation device is connected to the output end of the centrifugal filtration device, and is configured to perform solid-liquid separation of ammonium metavanadate filtrate to obtain clear ammonium metavanadate solution; The leaching device has its input end connected to the output end of the solid-liquid separation device, and is configured to receive vanadium slag roasted clinker and the ammonium metavanadate clear liquid for leaching to obtain vanadium leachate.

[0006] In some embodiments, the centrifugal filtration device includes: A pure water pump, wherein the input end of the pure water pump receives pure water; Wastewater discharge pneumatic valve, wherein the output end of the wastewater discharge pneumatic valve is configured to discharge wastewater; A filtrate discharge pneumatic valve, the output end of which is connected to the input end of the solid-liquid separation device; A centrifuge, the input end of which is connected to the output end of a pure water pump and receives the underflow of ammonium metavanadate precipitate, and the output end of which is connected to the wastewater discharge pneumatic valve and the filtrate discharge pneumatic valve respectively.

[0007] In some embodiments, the centrifuge is configured to wash and separate the ammonium metavanadate precipitate underflow to obtain ammonium metavanadate filter cake and wastewater, and to wash the ammonium metavanadate filter cake with pure water to obtain ammonium metavanadate filtrate.

[0008] In some embodiments, the output end of the centrifuge is configured to deliver wastewater and ammonium metavanadate filtrate to the wastewater discharge pneumatic valve and the filtrate discharge pneumatic valve, respectively.

[0009] In some embodiments, the solid-liquid separation device includes: A delivery pump, configured to deliver ammonium metavanadate filtrate; A concentrate pump, configured to deliver the concentrate produced after filtering ammonium metavanadate filtrate; An ultrafiltration centrifuge, wherein the output end of the ultrafiltration centrifuge is connected to the input end of the leaching device via the concentrate pump; A buffer mixing tank, the output of which is connected to the input of the ultrafiltration centrifuge via the delivery pump.

[0010] In some embodiments, the buffer stirring tank is configured to temporarily store the ammonium metavanadate filtrate by stirring.

[0011] In some embodiments, the ultrafiltration centrifuge is configured to perform solid-liquid separation on the ammonium metavanadate filtrate to obtain a concentrated solution and a clear ammonium metavanadate solution.

[0012] In some embodiments, the leaching apparatus includes: a solid-liquid separator; The input end of the solid-liquid separator is connected to the output end of the solid-liquid separation device.

[0013] In some embodiments, the solid-liquid separator is configured to perform solid-liquid separation on a slurry of vanadium slag roasted clinker and ammonium metavanadate clear liquid to obtain vanadium leachate.

[0014] In some embodiments, the pure water pump is configured to be interlocked with the filtrate discharge pneumatic valve, and the wastewater discharge pneumatic valve is configured to be interlocked with the filtrate discharge pneumatic valve.

[0015] The beneficial effects of this utility model are as follows: This invention recycles residual vanadium and reuses it in the production process of ammonium metavanadate, forming a closed-loop resource recycling system. It partially replaces primary vanadium raw materials in ammonium metavanadate production. This reduces wastewater generation while increasing the yield of ammonium metavanadate. The clarified liquid from the washing filtrate is reused, further reducing water consumption and lowering wastewater treatment costs. Attached Figure Description

[0016] To better understand this invention, reference can be made to the embodiments shown in the following figures. Components in the figures are not necessarily drawn to scale, and related elements may be omitted, or in some cases the scale may have been enlarged to emphasize and clearly illustrate the novel features described herein. Additionally, as is known in the art, system components may be arranged differently. Furthermore, in the figures, the same reference numerals denote corresponding parts throughout several views.

[0017] Figure 1 A reference schematic diagram of the co-treatment system for leaching ammonium metavanadate filtrate and vanadium slag roasted clinker of this utility model is shown. Figure 2 A schematic diagram of the module of the co-processing system for leaching ammonium metavanadate filtrate and vanadium slag roasted clinker of this invention is shown.

[0018] Explanation of reference numerals in the attached drawings: 11. Centrifuge; 12. Pure water pump; 13. Wastewater discharge pneumatic valve; 14. Filtrate discharge pneumatic valve; 21. Buffer mixing tank; 22. Transfer pump; 23. Ultrafiltration centrifuge; 24. Concentrate pump; 3. Solid-liquid separator. Detailed Implementation

[0019] It should be understood that the embodiments of the present invention shown in the exemplary embodiments are merely illustrative. Although only a few embodiments have been described in detail in this invention, those skilled in the art will readily recognize that various modifications are possible without substantially departing from the teachings of the present invention. Accordingly, all such modifications should be included within the scope of this invention. Other substitutions, modifications, variations, and deletions can be made to the design, operating conditions, and parameters of the following exemplary embodiments without departing from the spirit of the present invention.

[0020] like Figure 1 As shown, this utility model provides a synergistic treatment system for leaching ammonium metavanadate filtrate and vanadium slag roasted clinker, comprising: A centrifugal filtration device, wherein the input end of the centrifugal filtration device receives the ammonium metavanadate precipitate underflow and is configured to filter the ammonium metavanadate precipitate underflow to obtain ammonium metavanadate filtrate; A solid-liquid separation device, wherein the input end of the solid-liquid separation device is connected to the output end of the centrifugal filtration device, and is configured to perform solid-liquid separation of ammonium metavanadate filtrate to obtain clear ammonium metavanadate solution; The leaching device has its input end connected to the output end of the solid-liquid separation device, and is configured to receive vanadium slag roasted clinker and the ammonium metavanadate clear liquid for leaching to obtain vanadium leachate.

[0021] The ammonium metavanadate precipitate underflow and vanadium slag roasted clinker are the processing objects of the processing system in this embodiment. The ammonium metavanadate precipitate underflow can be an ammonium metavanadate slurry (AMV) obtained by roasting, leaching, and precipitation of vanadium slag, or it can be an ammonium metavanadate slurry obtained by further vanadium extraction from vanadium-containing raw materials such as steel slag, coal shale, and ferrophosphate. The vanadium slag roasted clinker refers to the clinker obtained by roasting vanadium slag with sodium salts, which can be sodium chloride or sodium carbonate.

[0022] like Figure 2 As shown, the processing system in this embodiment includes multiple modules. Centrifugal filtration device P1 washes and separates the ammonium metavanadate precipitate underflow, separating the residual precipitate from the ammonium metavanadate to obtain an ammonium metavanadate filter cake. The wastewater is directly discharged into the water treatment system. The ammonium metavanadate filter cake is then washed with pure water to further reduce the content of impurities such as sodium and sulfur in the ammonium metavanadate. The washing filtrate, after removing fine particles of ammonium metavanadate, is used as a leaching device. Solid-liquid separation device P2 separates the residual ammonium metavanadate in the washing filtrate. The concentrated liquid is reused in centrifugal filtration device P1, and the filtrate is used as a leaching device P3.

[0023] In some embodiments, the centrifugal filtration device includes: Pure water pump 12, the input end of which receives pure water; Wastewater discharge pneumatic valve 13, the output end of which is configured to discharge wastewater; A filtrate discharge pneumatic valve 14, the output end of which is connected to the input end of the solid-liquid separation device; Centrifuge 11, the input end of which is connected to the output end of pure water pump 12 and receives the underflow of ammonium metavanadate precipitate, and the output end of centrifuge 11 is connected to wastewater discharge pneumatic valve 13 and filtrate discharge pneumatic valve 14 respectively.

[0024] First, the centrifugal filtration device P1 will be described. Centrifugal filtration device P1 includes a centrifuge 11, a pure water pump 12, a wastewater discharge pneumatic valve 13, and a filtrate discharge pneumatic valve 14. The ammonium metavanadate precipitate underflow is continuously fed to the centrifuge 11. Most of the sodium and sulfur impurities contained in the ammonium metavanadate slurry are separated in the centrifuge. The sodium and sulfur impurities enter the water treatment unit for further processing through the wastewater discharge pneumatic valve 13. The pure water pump 12 is started, and pure water enters the centrifuge to wash the ammonium metavanadate cake. The washing filtrate enters the filtrate buffer mixing tank through the filtrate discharge pneumatic valve 14.

[0025] In centrifugal filtration unit P1, when the ammonium metavanadate precipitate underflow enters the unit, the powerful centrifugal force generated by high-speed rotation rapidly separates the precipitate residue from the ammonium metavanadate solid. This process not only achieves efficient solid-liquid separation, ensuring the rapid formation of the ammonium metavanadate filter cake, but also effectively removes most of the impurities adhering to the filter cake surface through washing, laying the foundation for subsequent deep purification. The separated wastewater is directly discharged into the water treatment system. Although the wastewater still contains a certain amount of residual vanadium and other impurities, subsequent water treatment processes can purify it to meet discharge standards, thus avoiding direct environmental pollution from untreated wastewater. Simultaneously, the high-efficiency separation capability of centrifugal filtration unit P1 effectively controls the moisture content of the ammonium metavanadate filter cake, reducing energy consumption in subsequent drying processes and improving overall production efficiency.

[0026] In some embodiments, the centrifuge 11 is configured to wash and separate the solid-liquid mixture of the ammonium metavanadate precipitate underflow to obtain ammonium metavanadate filter cake and wastewater, and to wash the ammonium metavanadate filter cake with pure water to obtain ammonium metavanadate filtrate.

[0027] Centrifuge 11 introduces ammonium metavanadate slurry for washing and separation to obtain ammonium metavanadate filter cake.

[0028] When the ammonium metavanadate precipitate flows into centrifuge 11, the solid particles in the material are rapidly separated from the liquid under the powerful centrifugal force generated by the high-speed rotation inside the centrifuge. This process is not only fast but also efficient, separating the ammonium metavanadate solids from the underflow in a short time to form an ammonium metavanadate filter cake. Simultaneously, the separated wastewater is discharged from a specific outlet of centrifuge 11. Compared to traditional filtration methods, this solid-liquid separation method has significant advantages such as fast separation speed, large processing capacity, and good separation effect, greatly improving production efficiency and reducing the production cycle.

[0029] In some embodiments, the output end of the centrifuge 11 is configured to deliver wastewater and ammonium metavanadate filtrate to the wastewater discharge pneumatic valve 13 and the filtrate discharge pneumatic valve 14, respectively.

[0030] The centrifuge 11, as the core solid-liquid separation equipment in the ammonium metavanadate production process, features a precise diversion mechanism at its output end, providing crucial assurance for the efficient resource utilization and environmental compliance of the entire production system. After washing and solid-liquid separation of the ammonium metavanadate precipitate underflow, the centrifuge 11 outputs two liquids with different properties: wastewater containing residual impurities and a small amount of ammonium metavanadate, and ammonium metavanadate filtrate with higher purity after multiple washings. The precise diversion and directional transport of these two liquids are crucial. The wastewater, containing a high concentration of impurities and a small amount of incompletely separated ammonium metavanadate, is transported to the wastewater treatment system via the wastewater discharge pneumatic valve 13. After purification through sedimentation, filtration, and neutralization, it meets discharge standards, preventing environmental pollution. The ammonium metavanadate filtrate, with its higher purity, can be used as a high-quality raw material or intermediate product and is transported to subsequent production processes via the filtrate discharge pneumatic valve 14.

[0031] In some embodiments, the solid-liquid separation device includes: Delivery pump 22, wherein the delivery pump 22 is configured to deliver ammonium metavanadate filtrate; Concentrate pump 24, wherein the concentrate pump 24 is configured to deliver the concentrate produced after filtering ammonium metavanadate filtrate; Ultrafiltration centrifuge 23, the output end of which is connected to the input end of the leaching device via the concentrate pump 24; A buffer mixing tank 21 is provided, and the output end of the buffer mixing tank 21 is connected to the input end of the ultrafiltration centrifuge 23 via the delivery pump 22.

[0032] Next, the solid-liquid separation device P2 will be described. The solid-liquid separation device P2 performs solid-liquid separation on the washing filtrate produced by the centrifugal filtration device P1. For this purpose, the solid-liquid separation device P2 consists of a buffer tank 21, a transfer pump 22, an ultrafiltration centrifuge 23, and a concentrate transfer pump 24. In the washing filtrate filtration device, the washing filtrate enters the buffer tank 21 and is pumped to the ultrafiltration centrifuge 23 by the transfer pump 22. The ultrafiltration centrifuge 23 separates the residual ammonium metavanadate concentrate from the clarified liquid in the washing filtrate. The ammonium metavanadate concentrate is returned to the centrifuge 11 by the concentrate pump 24, while the clarified liquid enters the vanadium slag roasting clinker leaching device to replace the production water for vanadium slag roasting clinker leaching.

[0033] The solid-liquid separation unit P2 plays an indispensable role in treating the washing filtrate. When the washing filtrate enters this unit, advanced solid-liquid separation technology thoroughly separates the residual ammonium metavanadate. The resulting concentrated solution, rich in ammonium metavanadate, is recycled to the centrifugal filtration unit P1 as a supplementary raw material to participate in the production process, maximizing the recovery and utilization of vanadium resources and reducing resource waste. The filtrate after treatment by the solid-liquid separation unit P2 has a further reduced impurity content and can be directly used in the leaching unit P3.

[0034] In some embodiments, the buffer stirring tank 21 is configured to temporarily store the ammonium metavanadate filtrate by stirring.

[0035] In some embodiments, the ultrafiltration centrifuge 23 is configured to perform solid-liquid separation on the ammonium metavanadate filtrate to obtain a concentrated solution and a clarified ammonium metavanadate solution. The ultrafiltration centrifuge 23 filters the washing filtrate, the concentrated solution is returned to the centrifuge for the production of ammonium metavanadate, and the filtrate is returned to the production unit to replace fresh water.

[0036] The centrifugal action of the ultrafiltration centrifuge 23 further enhances the separation effect. In the powerful centrifugal force field generated by high-speed rotation, solid particles in the concentrate are rapidly pressed against the inner wall of the drum, forming a dense filter cake layer. This process not only accelerates the solid-liquid separation speed but also further removes residual liquid from the filter cake through mechanical compression, increasing the concentration and purity of the concentrate. Meanwhile, the clarified liquid, under the combined action of centrifugal force and the permeability of the ultrafiltration membrane, is rapidly discharged from the center of the drum, avoiding remixing with the concentrate and ensuring the clarity and stability of the clarified liquid.

[0037] In some embodiments, the leaching apparatus includes: a solid-liquid separator 3; The input end of the solid-liquid separator 3 is connected to the output end of the solid-liquid separation device.

[0038] Finally, the vanadium slag roasting clinker leaching device P3 is described. Solid-liquid separator 3 is used to separate the slurry from the filtrate mixed with the vanadium slag roasting clinker, yielding vanadium leachate. The tailings are transported off-site for further processing.

[0039] As described above, according to this embodiment, the washing filtrate generated after the ammonium metavanadate precipitate underflow is washed and filtered in centrifuge 11 is then subjected to secondary filtration in ultrafiltration centrifuge 23. The concentrated liquid generated from filtration is returned to centrifuge 11 for recovery, while the clarified liquid enters the vanadium slag roasting clinker leaching device to replace fresh water for roasting clinker leaching. This reduces wastewater generation while increasing the yield of ammonium metavanadate. The reuse of the clarified liquid from the washing filtrate reduces water consumption and lowers wastewater treatment costs.

[0040] In the leaching unit P3, the filtrate serves as a leaching agent, which can efficiently leach vanadium from the raw material, improving leaching efficiency and reducing the consumption cost of the leaching agent.

[0041] In some embodiments, the solid-liquid separator 3 is configured to perform solid-liquid separation on a slurry containing vanadium slag roasted clinker and ammonium metavanadate clear liquid to obtain vanadium leachate.

[0042] Vanadium slag clinker, as the main carrier of vanadium, adsorbs a large amount of soluble vanadium compounds on its surface and in its pores, while ammonium metavanadate solution provides a suitable liquid environment and leaching agent composition. When the two are fully mixed in the feeding system of solid-liquid separator 3, the ions in the solution undergo chemical reactions such as dissolution and complexation with the vanadium compounds on the clinker surface, causing vanadium to gradually transfer into the liquid phase, forming a vanadium-containing slurry. During this process, solid-liquid separator 3 needs to ensure optimal reaction time and contact area through precise flow control and stirring intensity adjustment, thereby maximizing the vanadium leaching rate.

[0043] In some embodiments, the pure water pump 12 is configured to be interlocked with the filtrate discharge pneumatic valve 14, and the wastewater discharge pneumatic valve 13 is configured to be interlocked with the filtrate discharge pneumatic valve 14.

[0044] It should be noted that when the pure water pump 12 starts, the washing filtrate discharge pneumatic valve 14 is in the open state, and the pure water pump 12 is interlocked with the washing filtrate discharge pneumatic valve 14. The wastewater discharge pneumatic valve 13 and the filtrate discharge pneumatic valve 14 are interlocked with each other. When the wastewater discharge pneumatic valve 13 is open, the filtrate discharge pneumatic valve 14 is in the closed state, and vice versa.

[0045] The above embodiments are possible examples of implementations of this utility model, and are provided only to enable those skilled in the art to clearly understand the principles of this utility model. Those skilled in the art should understand that the above discussion of any embodiment is merely exemplary and is not intended to imply that the scope of the disclosed embodiments of this utility model includes the claims being limited to these examples. Under the overall concept of this utility model, the technical features of the above embodiments or different embodiments can also be combined with each other, resulting in many other variations of different aspects of the embodiments of this utility model as described above. For the sake of brevity, these variations are not provided in the specific embodiments. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the embodiments of this utility model should be included within the protection scope claimed by this utility model.

Claims

1. A system for synergistic treatment of ammonium metavanadate filtrate and vanadium residue roasting clinker leaching, characterized in that, include: A centrifugal filtration device, wherein the input end of the centrifugal filtration device receives the ammonium metavanadate precipitate underflow and is configured to filter the ammonium metavanadate precipitate underflow to obtain ammonium metavanadate filtrate; A solid-liquid separation device, wherein the input end of the solid-liquid separation device is connected to the output end of the centrifugal filtration device, and is configured to perform solid-liquid separation of ammonium metavanadate filtrate to obtain clear ammonium metavanadate solution; The leaching device has its input end connected to the output end of the solid-liquid separation device, and is configured to receive vanadium slag roasted clinker and the ammonium metavanadate clear liquid for leaching to obtain vanadium leachate.

2. The ammonium metavanadate filtrate and vanadium residue roasting clinker leaching synergistic treatment system according to claim 1, characterized in that, The centrifugal filtration device includes: A pure water pump (12) is provided, the input end of which receives pure water; Wastewater discharge pneumatic valve (13), the output end of which is configured to discharge wastewater; A filtrate discharge pneumatic valve (14) is provided, the output end of which is connected to the input end of the solid-liquid separation device. Centrifuge (11), the input end of the centrifuge (11) is connected to the output end of the pure water pump (12) and receives the underflow of ammonium metavanadate precipitate. The output end of the centrifuge (11) is connected to the wastewater discharge pneumatic valve (13) and the filtrate discharge pneumatic valve (14) respectively.

3. The ammonium metavanadate filtrate and vanadium residue roasting clinker leaching synergistic treatment system according to claim 2, characterized in that, The centrifuge (11) is configured to wash and separate the solid and liquid phases of the ammonium metavanadate precipitate underflow to obtain ammonium metavanadate filter cake and wastewater. The ammonium metavanadate filter cake is then washed with pure water to obtain ammonium metavanadate filtrate.

4. The ammonium metavanadate filtrate and vanadium residue roasting clinker leaching synergistic treatment system according to claim 3, characterized in that, The output end of the centrifuge (11) is configured to deliver wastewater and ammonium metavanadate filtrate to the wastewater discharge pneumatic valve (13) and the filtrate discharge pneumatic valve (14), respectively.

5. The ammonium metavanadate filtrate and vanadium residue roasting clinker leaching synergic treatment system according to claim 1, characterized in that, The solid-liquid separation device includes: A delivery pump (22) is configured to deliver ammonium metavanadate filtrate; Concentrate pump (24), wherein the concentrate pump (24) is configured to deliver the concentrate generated after filtering ammonium metavanadate filtrate; An ultrafiltration centrifuge (23) is provided, the output of which is connected to the input of the leaching device via the concentrate pump (24). A buffer mixing tank (21) is provided, the output of which is connected to the input of the ultrafiltration centrifuge (23) via the delivery pump (22).

6. The ammonium metavanadate filtrate and vanadium residue roasting clinker leaching synergistic treatment system according to claim 5, characterized in that, The buffer stirring tank (21) is configured to temporarily store the ammonium metavanadate filtrate by stirring.

7. The ammonium metavanadate filtrate and vanadium residue roasting clinker leaching synergistic treatment system according to claim 5, characterized in that, The ultrafiltration centrifuge (23) is configured to perform solid-liquid separation on the ammonium metavanadate filtrate to obtain a concentrated solution and a clear ammonium metavanadate solution.

8. The ammonium metavanadate filtrate and vanadium residue roasting clinker leaching synergic treatment system according to claim 1, characterized in that, The leaching device includes: a solid-liquid separator (3); The input end of the solid-liquid separator (3) is connected to the output end of the solid-liquid separation device.

9. The co-treatment system for leaching ammonium metavanadate filtrate and vanadium slag roasting clinker according to claim 8, characterized in that, The solid-liquid separator (3) is configured to perform solid-liquid separation on a slurry of vanadium slag roasted clinker and ammonium metavanadate clear liquid to obtain vanadium leachate.

10. The co-treatment system for leaching ammonium metavanadate filtrate and vanadium slag roasting clinker according to claim 2, characterized in that, The pure water pump (12) is set to interlock with the filtrate discharge pneumatic valve (14), and the waste water discharge pneumatic valve (13) is set to interlock with the filtrate discharge pneumatic valve (14).

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