RU2771973C1 - Sparger for high-pressure vessel - Google Patents

Abstract

FIELD: gas industry.

SUBSTANCE: invention relates to a sparger for a high-pressure vessel or autoclave, namely to a sparger equipped with a gas gate device. The sparger for use in the pulp of mineral-bearing particles contained in the high-pressure vessel, made with the possibility of operation at elevated temperature and high pressure, and with high-power agitators to create the specified pulp inside the high-pressure vessel, and with the possibility of injection of reagent media into the pulp, contains: a pipe, an open end of which can be located in the pulp and next to the corresponding agitator, wherein the pipe is made with the possibility of injection of reagent media into the pulp to reduce the reaction time and to control technological parameters for extraction of valuable minerals from the specified particles; a gas gate device located at the open end of the pipe and containing an outlet located downstream, the cross-sectional area of which is larger than the cross-sectional area of the open end of the pipe to reduce the flow of reagent media in the gas gate device to reduce wear and prevent ignition, and is significantly smaller than the area covered by the corresponding agitator to prevent the reverse flow of the pulp in the open end of the pipe under conditions of low or zero flow of the medium through the specified pipe and due to mixing of the pulp, caused by the operation of agitators; at the same time, the cross-sectional area of the medium flow passing through the pipe and the gas gate device increases in the direction of the flow of reagent media.

EFFECT: equipment of the sparger with a gas gate device to prevent the reverse flow of the pulp and solid materials into the sparger when used in a high-pressure vessel under conditions of low or zero flow of the medium through the sparger.

16 cl, 19 dwg

Description

FIELD OF THE INVENTION

The invention relates to a sparger for a pressure vessel or autoclave.

Namely, the present invention relates to a sparger provided with a gas barrier device for preventing backflow of pulp material into the sparger when used in a pressure vessel or autoclave. The gas seal arrangement largely prevents clogging of the sparger by solids settling by gravity under low flow or no flow (process/production shutdown) operating conditions.

TERMS AND DEFINITIONS

In the context of the present invention, the following terms and definitions are used:

The term "agitator" means a high-power agitator, which is usually located vertically from top to bottom, bottom-up, or located horizontally in the reaction chamber of a pressure vessel for mixing the slurry of ore-bearing material.

The term "autoclave" means a horizontal or vertical pressure vessel of the type commonly used in high pressure leaching processes. These autoclaves typically use agitators rather than spargers to keep the solids suspended in the liquid. Autoclaves are three-phase apparatuses while fluidized bed reactors are two-phase apparatuses. Such autoclaves are used to facilitate or accelerate reactions between phases in order to recover valuable minerals. These autoclaves must be operated in such a way as to prevent ignition and/or explosion of any phases in the autoclave, as any ignition is dangerous and may result in the destruction of process plant equipment and injury or death to nearby operators.

The term "gas cap" means a device, usually in the form of an inverted metal bowl with slits or grooves along the edges, which is located above the baffle opening in the reactor for contacting media exiting from under the baffle and entering the liquid that is already above the baffle. Gas caps are low pressure devices commonly used in two phase fluidized bed reactors. Most often, hundreds of gas caps are used in a reactor to liquefy a solid phase within a gas phase (or a solid phase within a liquid phase) in order to achieve the desired contact between the two phases of the reactor.

The term "elevated temperatures" means temperatures between 100°C and 300°C, and more specifically, temperatures between 150°C and 250°C. In contrast, operations at high temperatures, above 500° C. (and most often above 1000° C.), are usually characteristic of fluidized bed reactors with combustion or oxidation of one phase inside another.

The term "medium" means any substance that is capable of flowing and does not have a fixed form. This includes gases (such as steam or oxygen), liquids (such as water, acid or alkali), and slurries (such as a mixture of mineral-bearing particles in water or dilute acid or alkali).

The term "flow trajectories" means the trajectories along which the media flows in the sparger.

The term "fluidized bed reactor" means a reactor in which a liquid or gas is fed through the granular material above a perforated distributor at a flow rate sufficient to cause the granular material located above the distributor to have the properties of a liquid (i.e. fluidize) to increase contact between fluidizing medium and granular material and increase the rate of combustion or combustion of granular material in the reactor. Often, gas caps are fitted to the distributor to prevent the flow of granular material into the gas distributor and to increase the rate of liquid or gas injection to improve the mixing of the reactant media with the granular material and to prevent backflow of granular material into the gas distributor. Fluidized bed reactors are two-phase apparatuses that operate at atmospheric pressure (about 100 kPa or 1 bar) and high temperature.

The term "high power" means having enough power to mix 100 to 1000 tons of pulp in 20 to 60 seconds.

The term "high pressure" means pressures up to 6000 kPa (60 bar) which are commonly used in high pressure acid leaching (HPAL), pressure acid leaching (PAL) or pressure oxidation (POX) autoclave processes. The present invention relates to pressure vessels and is not applicable to fluidized bed reactors. Fluidized bed reactors cannot operate at high pressures, as such pressures are unacceptable, impractical, and dangerous in the oxidation or combustion processes for which fluidized bed reactors are designed.

The term "high temperature" means a temperature above 500°C, which usually occurs in the operation of fluidized bed reactors.

The term "low pressure" means either atmospheric pressure (about 100 kPa or 1 bar) or pressures up to 200 kPa (2 bar) which are typically found in fluidized bed reactors.

The term "reagents" refers to the media injected by the sparger of the present invention into the pressure vessel to increase the reaction rate or control process parameters. Typically, the reactants include substances such as oxygen, acid, alkali, water or steam in the liquid or gaseous phase.

The term "pulp" means a mixture of solid, liquid and/or gaseous phases in a fluid mixture having the properties of a liquid.

The term "sparger" means a device, usually in the form of a tube, which is used to inject a gas into a liquid, or to inject a gas or liquid into a slurry. In the context of the present invention, a sparger particularly refers to the injection of a gas and/or liquid into a medium in the form of a slurry of ore-bearing particles to supply reactants, control process parameters such as temperature, pressure and process reaction rate. Note that in some sources, the sparger is called a bubbler or sprinkler.

The term "vessel" in the context of the present invention most commonly means a high pressure reactor vessel such as an autoclave.

BACKGROUND TO THE INVENTION

High pressure autoclaves are used for intensive leaching of minerals from ores without the high energy costs associated with more traditional pyrometallurgical processes such as smelting. These autoclaves are typically horizontal vessels and have multiple agitators, for example 4 to 12 agitators, distributed along the length of the vessel to mix the mineral-containing slurry and reduce processing time. Agitators are high power agitators that typically require about 400 kW of electrical power to operate, capable of mixing the entire contents of an autoclave (most commonly 100 to 1000 tons) in a time span of 20 to 60 seconds.

High pressure autoclaves are sometimes equipped with sparger tubes for injecting gaseous reactants such as oxygen or liquids such as acid, alkali or water into the mineral-containing slurry. This is done to further reduce reaction times and control process parameters such as temperature and pressure. With such an autoclave arrangement, one sparger tube is usually provided for each agitator. One of the common problems with the use of sparger tubes in high pressure autoclaves is the tendency to fill the tubes and subsequently plug them with slurry and solids, which occurs during low injection flow or no flow operation (e.g. process or production shutdown). Cleaning of sparger tubes from clogging is most often achieved by flushing with cooling water or steam purging with the autoclave running (online). However, sometimes the cleaning of the sparger tubes requires mechanical cleaning of the sparger after the pressure in the vessel has been reduced. Online cleaning of blockages is carried out with the help of special shut-off and control valves, the operation of which in some installations may be necessary up to 12 times a day to constantly wash out the settled pulp, fragments of brick lining and scale from the sparger tubes. This frequent flushing can cause the supplier's recommended number of valve operations to be exceeded between maintenance periods very quickly. With such a high frequency of actuations, the recommended number of actuations is exceeded in less than 20 days, while the typical duration of an autoclave campaign can be more than a year. This negatively affects the productivity of autoclave operations and reduces the level of profitability. These valves are preferably serviced between campaigns.

Another difficulty in using sparger tubes in high-pressure autoclaves is to avoid high flow rates, which can lead to severe wear of the metal components of the pipe and even fire, and in the worst cases, loss of structural integrity and a sharp uncontrolled loss of pressure in the autoclave. . In order to achieve maximum flow rates in high-pressure autoclaves not exceeding 20 m/s, very careful design is required, which significantly reduces the risk of ignition of sparger tube metal materials in high oxygen concentration conditions. In addition, the critical flow rate of reactants under conditions of high oxygen concentration is pressure dependent. For example, at a pressure of 5.6 MPa (56 bar), the critical impact velocity of high purity oxygen is only 8 m/s.

In two-phase plants of the chemical industry, it is known to use gas caps which allow the reactive gas to be distributed in the phase of the processed solids in the form of bubbles. This distribution provides a more optimal contact between the media and the liquefaction of solids. The gas cap is usually an inverted metal bowl with slots or grooves along the edges, located above the pipe exiting the opening in the baffle of the fluidized bed reactor, to contact the gases escaping from under the baffle and entering the process fluid or granular solids, which are already above the barrier. Typically, hundreds of gas caps are used in fluidized bed reactors to achieve the desired two-phase contact. The use of these gas caps in pressure vessels or autoclaves is unknown. The gas cap as a low pressure device acts as a built-in solid and solid seal that prevents back flow of reactor materials under low gas flow conditions. In addition, the use of gas caps in conjunction with agitators is unknown, since agitators are not and cannot be used in fluidized bed reactors, and process media injectors are not and most often cannot be used in autoclaves for agitation. In addition, autoclaved materials cannot normally be agitated with a gas cap because the energy generated from the injection of the process fluid is not sufficient to shift the contents of the autoclave to achieve the desired level of agitation.

Gas caps are not analogous to spargers. Gas caps are two-phase devices required for a fluidized bed, while spargers are three-phase devices used in high pressure autoclaves. The gas caps serve to accelerate the flow of media injected into the low pressure reactors, to mix, disperse and keep the particles in suspension in the reactors. With regard to spargers, their main purpose is to supply reagents to pressure vessels, that is, in the work of spargers, the main emphasis is on reducing the flow rate of media and the corresponding reduction in wear and the risk of fire. The distribution of reagents and keeping the pulp components in suspension is the task of high-powered agitators, not spargers.

The gas caps have a low fit to provide maximum agitation at the bottom of the reactor, while the spargers are relatively long (relative to their diameter) to distance the injected reagents from the bottom of the vessel and reduce wear and local temperature fluctuations at the vessel walls.

The essential difference between high-pressure autoclaves and fluidized-bed reactors is that the former are equipped with high-power agitators (usually less than 12), which maintain a suspension of granular particles and distribute the feed gas, and in fluidized-bed reactors, the medium (usually in the form of combustible gases) at high flow rates are injected through hundreds of gas caps to expand and weigh the layer of granular particles with gas. The solids and gas (or liquid) in the bed expand and acquire the flow properties characteristic of a liquid, hence the name "fluidized bed reactor". In addition, autoclaves are designed to extract valuable minerals from ores, while fluidized bed reactors are used to burn, hydrolyze or oxidize granular materials. Autoclaves need to maintain relatively low media flow rates to avoid fires and increased wear, while fluidized bed reactors require high flow rates to keep granular materials fluidized for combustion purposes. Incineration is detrimental to autoclaves, and in fluidized bed reactors, incineration is the goal of the process. Accordingly, fluidized bed reactor technology is not applicable to the safe and efficient design and operation of autoclaves.

A problem for high pressure autoclaves is the fouling of traditional sparger tubes caused by low or no gas flow, which is often the case in normal operation. A solution to this plugging problem that has not been tried before is a gas seal device that serves to prevent the contents of the reactor chamber, mainly slurry, from flowing into the sparger under conditions of zero or low gas flow, and also to prevent solid particles from entering the sparger. under the influence of gravity. At low flow rates, the sealing device eliminates the need for a minimum flow rate at the outlet of the sparger, critical to prevent solids or slurry from entering the sparger by gravity. Such sealing device should not have any moving parts, and should exclude any flow paths through which high pressure media could bypass and bypass the sealing device, thereby canceling out its effect. A gas cap bolted to a sparger tube will create just such flow paths, and therefore will not be productive when used as a gas seal.

In addition, the sealing device should not introduce obstructions that could increase the flow rate of the injected medium and exceed the impact flow rate, i.e. the rate at which the metal components of the sparger ignite in the presence of high purity oxygen or are otherwise subject to increased wear. Typically this flow rate for oxygen is about 20 m/s, although the critical flow rate depends on the process fluid and operating parameters of the autoclave. Gas caps, on the other hand, are usually designed to increase the flow rate of the media through them, while limiting or reducing the flow rate of the injected media is not important and is not considered.

In the present invention, the sparger is provided with a gas seal device to prevent backflow of pulp and solids into the sparger when used in a pressure vessel such as an autoclave.

SUMMARY OF THE INVENTION

Thus, it is an object of the present invention to provide a sparger with a gas seal device to prevent backflow of slurry and solids into the sparger when used in a pressure vessel under conditions of low or no media flow through the sparger.

In accordance with one aspect of the present invention, there is provided a sparger for use in a pressure vessel operating at elevated temperatures and equipped with high power agitators to maintain a suspension of mineral-containing particles in the slurry, a sparger that injects reagent media into the slurry to reduce reaction time and to control process parameters. in order to extract valuable minerals from particles, a sparger consisting of:

pipe, the open end of which is located inside the pressure vessel next to the agitator; and

a gas seal device located at the open end of the pipe to prevent the backflow of pulp materials into the pipe under conditions of low or no flow of the medium through the specified pipe;

while the cross-sectional area of the pipe and the gas seal device is configured to maintain the flow of reagents at a level below the critical impact flow rate, the excess of which leads to increased wear and ignition in the presence of high purity oxygen.

The gas seal device may be fixed or removable attached to the open end of the pipe, or may simply be mounted adjacent to the open end of the pipe by attaching to another internal component of the autoclave.

A diffusion ring or a diffusion plate may be installed near the outlet of the gas seal device. It is designed to direct the flow of denser fluids, such as cooling water, radially to the sides, and not from top to bottom, as is the case with the outflow. The diffusion ring thus prevents localized cooling or high concentration of reactants at the bottom of the autoclave, and also promotes dispersion and promotes the reaction process.

In autoclaves having agitators, one or two spargers are typically provided at each agitator and/or located near each agitator. Namely, one sparger for each medium fed into the autoclave - as in some pressure vessel designs some media (such as oxygen and steam) must be kept separate from each other.

In accordance with another aspect of the present invention, there is provided a pressure vessel for recovering valuable minerals from mineral-containing particles, a pressure vessel, which consists of:

a reaction chamber containing a slurry of mineral-containing particles at high pressure and elevated temperature;

groups of agitators for pulp mixing; and

at least one sparger for injection of reagents into the pulp, where each sparger is located close to the corresponding agitator, sparger, consisting of:

pipes, the open end of which is brought into the reaction chamber; and

a gas seal device located at the open end of the pipe to prevent the backflow of pulp materials into the pipe under conditions of low or no flow of the medium through the specified pipe.

In accordance with a further aspect of the present invention, there is an autoclave process for recovering valuable minerals from mineral-containing particles, taking place in a reaction chamber equipped with a group of agitators, each of which is provided with at least one sparger. Such a sparger consists of a pipe, the open end of which is located inside the reaction chamber and a gas seal device installed at the open end of the pipe, to prevent the backflow of slurry materials into the pipe under conditions of low or no flow of the medium through the specified pipe. The technological process is divided into the following stages:

filling the reactor vessel with a pulp of mineral-containing particles;

pressurizing the reaction chamber until a high pressure is reached;

pulp mixing with agitators;

injection of reactive media into the reaction chamber using spargers; and

blocking the flow of said pulp materials from the reaction chamber into the pipe by means of a gas seal device.

Typically, in applications where the sparger is subject to corrosion and erosion, the sparger of the present invention may have a protective coating over all surfaces in contact with the process fluid. For example, a sparger of the present invention may have a cermet-sprayed coating or an outer sheath may be clad with a material different from that of the sparger itself over the entire surface of the sparger in contact with the process fluid. These agents serve as protection against corrosive and/or erosive attack which would otherwise result from contact with corrosive and/or erosive autoclave media.

Preferably, the protrusion of the sparger within the autoclave has a relatively large length compared to its diameter.

In the context of the present invention, the phrase "relatively long" when applied to a sparger tube means that the part of the sparger inside the autoclave has a length that is greater than 300% of the outer diameter of the sparger tube.

Most often, the sparger tube has a relatively large wall thickness compared to its diameter. However, the sparger tube can be made from a relatively thin wall material.

In the context of the present invention, the phrase "relatively thick" when applied to the wall of the sparger tube means that the wall thickness is greater than about 10% of the radial value of the sparger tube. However, the sparger wall can also be relatively thin.

Throughout the description, and unless the context otherwise requires, the word "consists" and its derivatives, such as "comprising", should be understood in the sense that the indicated whole parts or a group thereof are included, but other whole constituents are not excluded. or their groups. And also, the word "predominantly" or its synonyms, such as "preferably", "most often", "usually", should be understood in the sense that these whole parts or groups thereof are desirable, but are not necessarily essential for the operation of the invention.

BRIEF DESCRIPTION OF GRAPHICS

Below will be described exemplary embodiments of the present invention with reference to the accompanying drawings, in which:

Fig. 1 to 6 show a cross-sectional view of a portion of a conventional high pressure autoclave showing prior art configurations. Embodiments of these objects in the configuration of the present invention are shown in FIG. from 7 to 18 respectively;

Fig. 1 and 2 are cross-sectional views of a portion of a prior art conventional high pressure bottom feed sparger autoclave, FIG. 2 shows the sparger relative to the agitator on a smaller scale.

In FIG. 3 is a cross-sectional view of the high pressure autoclave of FIG. 1 and 2 of the prior art, shown on an even smaller scale;

Fig. 4 and 5 show cross-sectional views of top feed autoclaved spargers in two different orientations. In FIG. 4 shows a top feed sparger where the open/outlet end of the sparger tube is below the agitator in a vertical bottom-to-top position. In FIG. 5 shows a top feed sparger where the open/outlet end of the sparger tube is above the agitator in a horizontal position.

Fig. 6 is a cross-sectional view of a prior art side feed sparger where the horizontal open/outlet end of the sparger tube is below the agitator;

Fig. 7 and 8 show cross-sectional views of a portion of a high pressure autoclave, where the bottom feed sparger is provided in accordance with one embodiment of the present invention. Fig. 8 is shown on a smaller scale, showing the sparger in relation to the agitator, as well as the gas seal device mounted on the sparger tube;

Fig. 9 is a cross-sectional view of the high pressure autoclave of FIG. 7 and 8 on an even smaller scale;

In FIG. 10 is a cross-sectional view of the sparger of FIG. 7 shown alone;

Fig. 11 and 12 are cross-sectional views of a portion of a high pressure autoclave with a bottom feed sparger in accordance with another embodiment of the present invention. In FIG. 12 is a smaller scale view of the sparger in relation to the agitator with the gas seal device mounted on the agitator;

Fig. 13 is a cross-sectional view of the high pressure autoclave of FIG. 11 and 12 on an even smaller scale;

Fig. 14 is a cross-sectional view of a portion of a high pressure autoclave with a top feed sparger in accordance with yet another embodiment of the present invention.

Fig. 15 shows a cross-sectional view of the high pressure autoclave of FIG. 14 on a smaller scale;

Fig. 16 is a cross-sectional view of a portion of a high pressure autoclave showing a side feed sparger in accordance with yet another embodiment of the present invention.

Fig. 17 shows a cross-sectional view of the high pressure autoclave of FIG. 16 on a smaller scale;

In FIG. 18 is a single cell cross-sectional view of a high pressure autoclave showing the bottom feed sparger of Figure 7 in relation to the agitator; and

In FIG. 19 is a top perspective view of a high pressure autoclave divided into 6 cells each containing one sparger of the present invention.

PRIOR ART

In FIG. 1 to 3 show a pressure vessel in the form of a high pressure autoclave 10 with a traditional bottom feed sparger 12 installed through the flange 14 of a prior art autoclave. The autoclave 10 also typically has an agitator 16 for mixing the slurry consisting of mineral ore and reactive media (most often a strong acid). The autoclave 10 is typically divided into 4 to 8 cells (similar to 6 cells, as shown in FIG. 19), each containing one sparger 12 and one agitator 16. A limitation on the functionality of the sparger 12 is its susceptibility to pulp fouling. material under conditions when the flow of the medium into the autoclave 10 through the sparger 12 is reduced or stopped.

In FIG. 7 to 17 show spargers 20, 40, 60, and 80 according to several embodiments of the present invention, each of which has the advantage that backflow of pulp materials into the sparger tube is prevented by a gas seal arrangement. The following provides a more detailed description of each embodiment of the invention, with similar parts having the same numerical designation.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In FIG. 7 to 9 show a bottom feed sparger 20, consisting of a sparger tube 22, the open end 24 of which enters the high pressure autoclave 26 through a flange 28. The sparger 20 also has holes 29 located at the end of the sparger tube 22, over which there is a hinged inverted cap 30. The inverted cap 30 is upside down so that the mineral particles agitated in the autoclave 26 do not settle or settle in the sparger tube 22 under the influence of gravity. The inverted cap 30 and the open end 24 of the sparger tube 22 form an annular outlet 32.

The sparger tube 22 may be introduced into the autoclave 26 from below, to the side, or from above the agitator 16 provided that the media exiting the sparger tube 22 are discharged near one of the agitators 16 and distributed by the agitators 16 to increase the rate of process reactions. or for the desired change in process parameters. In order to provide a seal function, the orientation of the outlet 32 must be arranged so that mineral-bearing materials and fragments of refractory brick lining cannot enter or settle in the sparger tube 22 under the influence of gravity.

Preferably, the cross-sectional area of the holes 29 should be larger than the cross-sectional area inside the sparger tube 22, as this prevents an increase in the flow rate of media into the autoclave 26 through the sparger 20.

Most often, the autoclave 26 is in the form of a cylinder with domed ends. Most often, the autoclave 26 is positioned horizontally, although it can also be positioned vertically.

Most commonly, the autoclave 26 has a resistant brick lining or chemically resistant metal alloy cladding that protects the top metal layer of the autoclave 26 from the temperatures and corrosive materials contained in the autoclave 26 during operation.

As an added benefit, sparger 20 is also provided with a diffusion ring or diffusion plate 34 located at pipe 22 and outlet 32 to ensure that the flow of denser media, such as cooling water, exiting sparger 20 is radially away from pipe 22. , and not axially down along the tube 22. The diffusion ring 34 thus prevents localized cooling or high concentrations of reactants at the bottom of the autoclave 26, and also promotes dispersion and promotes the reaction process.

As an additional advantage, the sparger 20 may have a protective coating partially or completely enclosing the outer surface in contact with the process fluid. For example, the sparger 20 may have a ceramic-metal spray coating, an outer sheath, or a cladding. These agents serve as protection against corrosive and/or erosive attack which would otherwise result from contact with autoclaved media.

Preferably, the annular outlet 32 is larger in cross-sectional area than the holes 29, thus preventing an increase in the flow rate of media into the autoclave 26 through the sparger 20.

Open end 24, openings 29, inverted cap 30, and annular outlet 32 collectively form the sealing device of the present invention in this bottom-feed configuration. The gas seal is created when the flow of sparger media from outlet 32 is stopped. Under such conditions, the pressure of the media inside the sparger tube 22 and the pressure of the media inside the autoclave 26 are equal. Accordingly, a reverse flow of the medium into the sparger tube 22 is not possible. In addition, no flow of particles under gravity is possible, since the holes 29 are higher than the annular outlet 32.

In FIG. 10 shows the gas seal arrangement of the present invention on a larger scale. The gas seal device is formed from the open end 24 of the sparger tube 22, the holes 29, the inverted cap 30 and the annular outlet 32 formed between the inverted cap 30 and the diffusion ring 34. The cross-sectional area of the annular outlet 32 is larger than the cross-sectional area of the holes 29, which, in turn, more than the cross-sectional area of the sparger tube 22.

The inverted cap 30 is conveniently attached to the open end 24 of the sparger tube 22 by means of a threaded connection. It is critical that the length and pitch of the threaded connection be designed to prevent flow of media along the threads between the inverted cap 30 and end 24, as such flow would allow slurry to enter the sparger 20 and foul it, thereby impairing the functionality of the gas seal device.

In FIG. 9, 13, 15 and 17, the typical level of pulp contained in autoclave 26 is shown and numbered 36 and is referred to as pulp level 36.

In FIG. 11 to 13 show the bottom feed sparger 40, which is similar to the bottom feed sparger 20, and the same parts in the figures have the same numerical designation.

The difference between the sparger 40 and the sparger 20 is that the sparger 40 has a hinged inverted cap 42, which is mounted on the agitator 16 and is located at the open end 44 of the sparger tube 22 to form the outlet 32. In this embodiment, the inverted cap 42 rotates together with the agitator 16 and does not is not attached to the sparger tube 22. In addition, the open end 44 of the sparger tube 22 has only one hole 46, but multiple holes can be provided like the holes 29.

Open end 44, opening 46, inverted cap 42, and annular outlet 32 collectively form the sealing device of the present invention. The gas seal is created when the flow of sparger media from outlet 32 is stopped. Under such conditions, the pressure of the media inside the sparger tube 22 and the pressure of the media inside the autoclave 26 are equal. Accordingly, a reverse flow of the medium into the sparger tube 22 is not possible. In addition, the flow of particles under gravity is not possible, since the opening 46 is higher than the annular outlet 32.

In FIG. 14 and 15 show the top feed sparger 60, which is similar to the sparger 20, and the same parts in the figures have the same numerical designation.

The difference between sparger 60 and sparger 20 is that sparger 60 does not have an inverted cap. The sparger tube 62 of the sparger 60 is introduced into the autoclave 26 from above or to the side of the agitator 16 and ends with a horizontal end plate 64. The sparger tube 62 differs from the sparger tube 22 in that it has a branch 65 at its open end. The sparger tube 62 has openings 66, having a winning elongated oval shape, located above the end plate 64. The cross-sectional area of the holes 66 is preferably larger than the cross-sectional area of the sparger tube 62, which prevents an increase in the flow rate of the media supplied through the sparger tube 62 into the autoclave 26. End plate 64 is the equivalent of diffusion ring 34.

Also, sparger 60 differs from sparger 20 in that it does not have an annular outlet. In this embodiment, openings 66 form an outlet for the flow of sparger media. In addition, the holes 66 are located so that mineral-bearing materials and fragments of the refractory brick lining cannot enter the sparger tube 62 under the influence of gravity.

The sparger tube 62 may be introduced into the autoclave 26 at the side or top of the agitator 16 provided that the media exiting the sparger tube 62 are discharged near one of the agitators 16 and distributed by the agitators 16 to increase the rate of process reactions or to change the parameters as desired. process. It is also necessary to direct the outlet 32 downwards so that mineral-bearing materials and fragments of the refractory brick lining cannot enter the sparger tube 22 under the influence of gravity.

The end plate 64, outlet 65, and openings 66 collectively create the gas seal device of the present invention. The gas seal is created when the flow of sparger media from the holes 66 is stopped. Under such conditions, the pressure of the media inside the sparger tube 62 and the pressure of the media inside the autoclave 26 are equal. Accordingly, a reverse flow of the medium into the sparger tube 62 is not possible. It is also impossible for particles to flow under the influence of gravity, since the holes 66 are below the level of the outlet 65 and the rest of the sparger tube 62.

In FIG. 16 and 17 show the side feed sparger 80, which is similar to the sparger 20, and the same parts in the figures have the same numerical designation.

The difference between the sparger 80 and the sparger 20 is that its sparger tube 82 is located horizontally in the autoclave 26. The sparger tube 82 terminates in a blind end 84. The sparger tube 82 also has an opening 86 in the lower portion for the discharge of sparger media. Opening 86 is positioned to prevent mineral-bearing particles and fragments of refractory brick lining from entering sparger tube 82 under the influence of gravity.

Blind end 84 and opening 86 together create a gas seal device of the present invention. The gas seal is created when the flow of sparger media from the opening 86 is stopped. Under such conditions, the pressure of the media inside the sparger tube 82 and the pressure of the media inside the autoclave 26 are equal. Accordingly, a reverse flow of the medium into the sparger tube 82 is not possible. It is also impossible for particles to flow under the influence of gravity, since the opening 86 opens downward and is located below the level of the rest of the sparger tube 82.

When appropriate, spargers 40, 60, and 80 may have a protective coating over the entire outer surface in contact with the process fluid, similar to sparger 20. For example, spargers 40, 60, and 20 may have a ceramic-metal spray coating, outer sheath or plating. These agents serve as protection against corrosive and/or erosive attack which would otherwise result from contact with autoclaved media.

Spargers 40 and 60 can be equipped with a diffusion ring or diffusion plate, similar to the diffusion ring 34 of sparger 20.

Preferably, the protrusion of the sparger tube 22 within the autoclave 26 has a relatively large length compared to its diameter.

In the context of the present invention, the phrase "relatively long" when applied to the sparger tube 22 means that the portion of the sparger tube 22 inside the autoclave 26 has a length that is greater than 300% of the outer diameter of the sparger tube 22.

Most often, the sparger tube 22 has a relatively large wall thickness compared to its diameter. However, the sparger tube 22 can be made from a relatively thin wall material.

In the context of the present invention, the phrase "relatively thick" when applied to a pipe wall means that the wall thickness is greater than about 10% of the value of the pipe radius.

Advantageously, the sparger tube 22 is made from stainless steel metals, chemically resistant alloys (such as tantalum), or the like.

Figure 19 shows an autoclave 26 equipped with six spargers 20 of the present invention. In FIG. 18 shows one cell of the autoclave 26. The autoclave 26 may have a traditional design and execution in terms of the arrangement of spargers 20, 40, 60, 80. Usually there is one sparger 20, 40, 60 or 80 for each cell, but there may be two or more spargers 20, 40, 60 or 80 in one cell. However, there is usually only one agitator 16 per cell.

From a sealing point of view, it is preferred that the cross-sectional area increase from the area of the sparger tube 22, 62, and 82 to the area of the outlet 32, openings 66, and opening 86, respectively, in order to reduce the flow rate of the sparger media entering the autoclave 26 and reduce the risk of fire in the sparger room. tubes 22, 62, and 82. The increase in cross-sectional area acts as a measure to ensure that the flow velocity of the sparger media is maintained below the critical shock flow velocity, which is approximately 20 m/s. If this critical flow rate is exceeded, and with other contributing factors, the oxygen or other flammable media supplied to the autoclave 26 may ignite the metal (e.g., titanium, stainless steel, and some alloys) of the sparger tubes 22, 62, and 82 and the gas seal device. .

In other words, it is preferable that the cross-sectional area of the sparger tube 22, 62 and 82 and the gas barrier device increase in the direction of the reactant flow in order to prevent high flow rates that can lead to severe wear of the metal components of the pipe and even fire, and in the worst cases - to loss of structural integrity and abrupt uncontrolled loss of pressure in the autoclave 26. In order to ensure maximum flow rates in high-pressure autoclaves, not exceeding 20 m/s, very careful design is used, which significantly reduces the risk of ignition of metallic materials of the sparger tube in conditions of high oxygen concentration and typical pressure. However, the critical flow rate of reactants under conditions of high oxygen concentration is pressure dependent. For example, at a pressure of 5.6 MPa (56 bar), the critical impact velocity of high purity oxygen is only 8 m/s.

Preferably, the overall increase in the cross-sectional area of the sparger tube 22, 62 and 82 and the gas seal device in the direction of the flow of reagents injected into the autoclave 26.

It is preferred that the cross-sectional area of the gas seal device be at least 100% larger than the cross-sectional area of the sparger tube 22, 62 and 82.

In the most optimal design, the cross-sectional area of the gas seal device is at least 200% larger than the cross-sectional area of the sparger tube 22, 62 and 82.

It is important to exclude any flow paths into the sparger tube 22, 62 and 82, as well as into the area before the gas seal device. This is because any connections that form part of the sparger 20, 40, 60, 80 or gas seal device create potential high pressure flow paths leading from the autoclave 26 to the interior of the sparger tube 22, 62 and 82. Accordingly, bolted connections through the sparger tube 22, 62 and 82. Any connections that form part of the sparger or gas seal device must completely prevent media flow through the wall of the sparger tube 22, 62 and 82 directly into or out of the autoclave 26.

APPLICATION

In practical applications, the sparger 20, 40, 60, or 80 is installed in the autoclave 26 by means of a flange 28. The flange 28 seals with the sparger tube 22, 62, and 82 and prevents high pressure media from escaping from the autoclave 26.

The spargers 20 and 60 are installed in the flange 28 from the inside of the autoclave 26. While the spargers 40 and 80 can be introduced into the autoclave 26 through the flange 28 from the outside of the autoclave.

During normal operation of the bottom feed sparger 20, the flow of sparger media is directed upward through the spager tube 22, through the open end 24 of the sparger tube 22, through the holes 29 and exits the inverted cap 30 through the outlet 32 into the autoclave 26 at the diffusion ring 34. The diffusion ring 34 serves to directing denser sparger media, such as water, away from the sparger tube 22. Agitator 16 then mixes the sparger media with the slurry 36 to speed up the reaction or control manufacturing processes.

When using the bottom feed sparger 40, the flow of sparger media is directed upward through the spager tube 22, through the open end 44 into the inverted cap 42 and out through the outlet 32 into the autoclave 26 as the inverted cap 42 rotates along with the agitator 16. The agitator 16 then mixes the sparger media with pulp.

When using the top feed sparger 60, the sparger media flow is directed down through the spager tube 62, hits the end plate 64 and flows out through the holes 66 into the autoclave 26 adjacent to the agitator 16, which then mixes the sparger media with the pulp 36.

When using the side feed sparger 80, the sparger media flow passes through the sparger tube 82 and exits through the opening 86 into the autoclave 26.

The sparger media can be dilute acid or dilute alkali, water, steam, or a gas such as, for example, oxygen. The sparger media must not be allowed to ignite or ignite any material within the autoclave 26 otherwise the autoclave 26 may explode.

In each embodiment of the present invention, under conditions of zero or low flow of the sparger medium, the pressure inside the sparger tubes 22, 62 and 82 is the same as the pressure inside the autoclave 26. In this way, a gas seal is achieved that prevents backflow of the medium from the autoclave 26 into the sparger tubes 22, 62 and 82.

Also, due to the position and orientation of the outlet 32, openings 66 and opening 86, solid particles inside the autoclave cannot, under the influence of gravity, enter the sparger tubes 22, 62 and 82. In this way, clogging of the sparger tubes 22, 62 and 82 is significantly prevented.

INDUSTRIAL APPLICABILITY

The sparger 20, 40, 60, 80 of the present invention is suitable for use in increasing the rate of reaction processes in a pressure vessel such as an autoclave to extract valuable minerals from ore without the use of pyrometallurgical methods and processes.

The sparger 20, 40, 60, 80 of the present invention belongs to and is used in the field of autoclave processing of minerals at high pressure and at elevated temperature in order to extract valuable minerals from ore.

A consequence of the use of the sparger 20, 40, 60, 80 of the present invention is the ability to feed reagents into the autoclave without the risk of fouling the sparger tube 22, 62 and 82 with slurry or slurry material even under low or no flow conditions. As a result, production downtime is avoided which would otherwise result from the need to clean prior art sparger tubes used in autoclaves.

In addition, the sparger 20, 40, 60, 80 of the present invention is designed to slow down the flow of reactive media into the autoclave 26 in order to reduce the risk of fire or wear of the metallic materials used in the manufacture of the sparger 20, 40, 60, 80.

REFERENCE POSITIONS

The following reference numerals are used in the description:

PRIOR ART

10 high pressure autoclave

12 sparger

14 flange

16 agitator

PRESENT INVENTION

20 bottom feed sparger

22 sparger pipe

24 open end - sparger pipe

26 autoclave

28 flange

29 holes

30 inverted cap

32 ring release

34 diffusion ring

36 pulp level

40 bottom feed sparger

42 inverted cap

44 open end - sparger pipe

46 hole

60 top feed sparger

62 sparger pipe

64 end plate

65 branch

66 holes

80 side feed sparger

82 sparger pipe

84 blind end

86 opening

GAS SHUTTER DEVICE

The open end 24, holes 29, inverted cap 30, and annular outlet 32 together form a gas seal device in an embodiment of the present invention with a bottom feed sparger 20, where the inverted cap 30 is mounted on the sparger tube 22.

Open end 44, opening 46, inverted cap 42, and annular outlet 32 together form the gas seal device in the bottom feed sparger embodiment of the present invention, where the inverted cap 42 is mounted on agitator 16.

The end plate 64, outlet 65, and openings 66 together form the gas seal device in the top feed sparger 60 embodiment of the present invention, where the sparger tube 62 is introduced through the top region of the autoclave 26 above the agitator 16.

Blind end 84 and opening 86 together create a gas seal device of the present invention in the implementation with sparger pipe 82 side feed.

BENEFITS

The spargers 20, 40, 60, and 80 of the present invention have the advantage of including a gas seal device that prevents the flow of solids and slurry material back into the sparger in low or no flow situations that often occur in high pressure autoclave 26 operation. pressure.

Spargers 40 and 80 have the additional advantage of being able to be dismantled and serviced without the need for personnel to enter the autoclave 26.

The spargers 20, 40, 60, 80 have the additional advantage that the cross-sectional area of the media passages through them increases in the direction of the reactant flow, thus maintaining the reactant flow rate below the critical shock flow rate, above which the pipe materials are likely to ignite. 22, 62 and 82 and sealing devices in the presence of high purity oxygen or the possibility of increased wear of these materials.

The coating of spargers 20, 40, 60 and 80 provides the further benefit of reducing the wear on their outer surface in contact with the process fluid and increasing the time intervals between maintenance of spargers 20, 40, 60 and 80.

The spargers 20, 40, 60, 80 have the further advantage of eliminating media flow paths through the wall of the sparger tube 22 or the gas seal wall.

Diffusion ring 34 and plate 64 have the advantage of directing media discharged from the sparger away from the sparger tube and from the bottom of autoclave 26 and extend the life of spargers 20 and 40 and autoclave 26. Rings 34 and 64 generally provide an advantage in applications denser media such as liquids. Rings 34 and 64 are not as useful in cases where only very low density media such as gas or steam are used. This is because the buoyant force of very low density media dominates the relatively low driving force of the released media.

MODIFICATIONS AND VARIATIONS

For persons competent in the relevant fields of technology, it will be obvious that various methods of modification and improvement can be applied to the above embodiments of the invention, supplementing the methods already described without departing from the main idea of the present invention. For example, other forms of protective coating may be used. In addition, other sparger configurations may be used that retain the gas seal arrangement. In addition, while the sparger outlet 34 is usually described as being annular, it may have other shapes such as, for example, an elongated oval shape as shown in the holes 66.

Claims (35)

1. Sparger for use in the slurry of mineral-bearing particles contained in a pressure vessel, designed to operate at elevated temperature and pressure and with high-power agitators to create the specified slurry inside the pressure vessel and with the possibility of injecting reagent media into the slurry, moreover sparger contains: a pipe, the open end of which can be located in the pulp and next to the appropriate agitator, and the pipe is configured to inject reagent media into the pulp to reduce the reaction time and to control process parameters for the extraction of valuable minerals from these particles; a gas seal device located at the open end of the pipe and containing an outlet located downstream, the cross-flow area of \u200b\u200bwhich more cross-flow area of the open end of the pipe to reduce the flow of reagent media in the gas seal device to reduce wear and prevent fire and significantly less than the area covered by the corresponding agitator, to prevent the backflow of pulp into the open end of the pipe in conditions of low or no flow of the medium through the specified pipe and due to the mixing of the pulp caused by the operation of the agitators; in this case, the cross-sectional area of the medium flow passing through the pipe and the gas seal device increases in the direction of the flow of the reagent media. 2. The sparger according to claim 1, in which the gas seal device extends from the corresponding agitator, is located at the open end of the pipe and is rotatable relative to said pipe, and the gas seal device is not attached to the open end of the pipe. 3. Sparger according to claim 1, wherein the gas seal device is fixedly attached to the open end of the pipe to prevent movement relative to the pipe. 4. Sparger according to claim 1, also containing a diffusion ring located around the open end of the pipe near the outlet of the gas seal device and below it, and the diffusion ring is located with the possibility of directing the flow of injected reagent media essentially radially outward from the pipe. 5. Sparger according to claim 1, in which the entire surface of the pipe and the gas seal device in contact with the process medium is coated with a protective coating to protect against corrosive and/or erosive effects. 6. Sparger according to claim 5, in which the coating is selected from one of the ceramic-metal spray coating, the outer shell and the cladding with a material different from the material of the pipe and the gas seal device. 7. Sparger according to claim 4, in which the gas seal device also contains an inverted cap located above the open end of the pipe and forming with said open end a downstream outlet, said outlet being annular and its cross-flow area larger than the cross-flow area. sections of the open end of the pipe to reduce wear and prevent fire. 8. The sparger according to claim 7, in which the inverted cap has a downwardly directed circumferential wall bounding said annular outlet with an open end of the pipe, and the length of the annular outlet in the direction of flow of the reagent media is greater than the width of the annular outlet in the direction transverse to the direction of the flow of the reagent media, for to prevent backflow of pulp into the gas seal device, the circumferential wall terminating near and above the diffusion ring to direct the injected reactant media into the diffusion ring and thus substantially radially outward from the pipe. 9. Pressure vessel for extracting valuable minerals from mineral-bearing particles, containing: a substantially cylindrical reaction chamber, located horizontally and designed to contain a pulp of mineral-bearing particles at elevated pressure and elevated temperature, and the reaction chamber at one end has an inlet for receiving said particles, and at the opposite end has an outlet for discharging treated particles; a group of high-power agitators located inside the reaction chamber and distributed along its length for pulp mixing and distribution of reagent media; and at least one sparger located in the vicinity of a respective agitator, each sparger comprising: a pipe, the open end of which is located in the slurry for injecting reagent media into the slurry; and a gas seal device located at the open end of the pipe and containing an outlet located downstream, the cross-flow area of \u200b\u200bwhich more cross-flow area of the open end of the pipe to reduce the flow of reagent media to reduce wear and prevent fire and significantly less than the area covered by the corresponding agitator, to prevent the backflow of pulp materials into the open end of the pipe in conditions of low or no flow of the medium through the specified pipe and due to the mixing of the pulp caused by the operation of the agitators, in this case, the cross-sectional area of the medium flow passing through the pipe and the gas seal device increases in the direction of the flow of the reagent media. 10. The vessel according to claim 9, also containing a diffusion ring located around the open end of the pipe near the outlet of the gas seal device and below it, and the diffusion ring is located with the possibility of directing the flow of injected reagent media essentially radially outward from the pipe. 11. The vessel according to claim 10, in which the gas seal device also contains an inverted cap located above the open end of the pipe and forming, with said open end, a downstream outlet, said outlet being annular and its cross-flow area larger than the cross-flow area. sections of the open end of the pipe to reduce wear and prevent fire. 12. The vessel according to claim 11, in which the inverted cap has a circumferential wall directed downwards, limiting the specified annular outlet with the open end of the pipe, and the length of the annular outlet in the direction of the flow of the reagent media is greater than the width of the annular outlet in the direction transverse to the direction of the flow of the reagent media, for prevent backflow of pulp into the gas seal device. 13. A method of operating a high-pressure autoclave for extracting valuable minerals from mineral-bearing particles suspended in the pulp in a reaction chamber equipped with a group of high-power agitators, each of which is associated with at least one sparger, each sparger containing a pipe, the open end of which can be located in the pulp, and a gas seal device located at the open end of the pipe and containing an outlet located downstream, the cross-sectional flow area of which is greater than the cross-flow area of the open end of the pipe and significantly less than the area covered by the corresponding agitator, while the cross-sectional area the flow of the medium passing through the pipe and the device of the gas seal increases in the direction of the flow of the media of the reagents, and the method includes the following steps: essentially filling the reaction chamber with liquid and mineral-bearing particles; heating the pulp to an elevated temperature and pressurizing the reaction chamber to an elevated pressure to reduce the reaction time and to control process parameters for the extraction of valuable minerals; agitating the liquid and said particles with pulp agitators; injection of reactant media into the reaction chamber near the agitators by means of spargers, wherein the flow of reactant media is directed down into the pulp through said outlet; distribution of reagent media in the pulp with the help of agitators and reduction of the reagent consumption inside the pipe to the outlet in the direction of the specified flow by making the outlet cross-flow section with an area that is greater than the pipe cross-flow area, and preventing the back flow of pulp into the gas seal device under conditions of low or zero flow of the reagent medium through the specified pipe by making the cross-sectional flow section of the outlet with an area that is significantly less than the area covered by the corresponding agitator. 14. The method of claim 13, wherein said injection reduces the flow rate of injected reactant media from the pipe to the gas seal device and reduces the flow rate of injected reactant media from the gas seal device to the reaction chamber to reduce wear and prevent ignition. 15. The method of claim 13, wherein the flow of reactant media from the gas seal device is directed substantially radially outward from the pipe by means of a diffusion ring located around the open end of each of said pipes. 16. The method of claim 13 wherein, while preventing backflow, the flow path of the reactant media in said outlet is longer than the width of the outlet in a direction transverse to the flow direction of the reactant media.

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