FI121091B - Pump and method for dismantling the pump - Google Patents

Description

PUMP AND METHOD FOR DISMANTLING PUMP FIELD OF THE INVENTION

The invention relates to a pump as defined in the preamble of claim 15. The invention further relates to a method for disassembling a pump as defined in the preamble of claim 13.

In particular, the invention relates to a pump capable of pumping large volumes of fluid, in particular extraction solution, in hydrometallurgical metals recovery processes using liquid-liquid extraction.

BACKGROUND OF THE INVENTION

In the hydrometallurgical recovery of metals, the following steps can be distinguished: leaching of the concentrate or ore, liquid-liquid extraction and precipitation or reduction of the metal. In leaching, the ore or concentrate is typically leached with mineral acid to give a metal of value 20 in aqueous solution. In the extraction, the aqueous solution containing the precious metal and numerous impurities from the leaching is mixed with the organic extractant solution in the extraction apparatus, or is typically a mixer-settler cell or column. Thereby, the metal to be processed selectively reacts with the extractant in an ion exchange reaction or other chemical mechanism, dissolving in the organic phase as an organometallic complex to separate the metal from the aqueous solution. The aqueous solution from which the precious metal is separated can be returned to the leaching step. The extraction solution, in turn, is subjected to a back extraction step in which the precious metal bound to it is returned to the extraction reaction by an inverse reaction in an aqueous solution, from which it can be processed to product 35 by precipitation into a metal compound or electrolytically reduced to metal.

2

Thus, in liquid-liquid extraction, two insoluble liquids are mixed in an extractor mixer such that one of the liquids is disintegrated into droplets into the other liquid to disperse, thereby allowing efficient fluid transfer between the liquids. Mixing takes place in the mixer settler in the pumping section which at the same time maintains the flow of solutions between the process steps. In the clarifying section of the extraction apparatus, the mixed liquids are separated by a combination of droplets 10 and gravity. The extraction plant process typically includes a number of serially connected extraction and back extraction steps, and possibly other additional steps, such as the extraction solution washing and regeneration steps.

15 As the extraction plant circulates the extraction solution continuously through various stages of the process, its volume varies in stages, e.g. as a result of varying the rate of degradation of the liquid-liquid dispersion in the clarifying portion. To balance volume fluctuations, a wide-area storage tank is provided in 20 processes where the surface of the solution can be raised and lowered. The volume flow rate of the leach solution may be in the range of 500 to 2500 m3 / h, depending on the capacity of the process.

It is known in the art that extraction solution 25 is pumped from the storage tank back to the process steps, usually with large centrifugal pumps. Such a known pump includes a housing having a hollow interior, an inlet for allowing fluid to enter the interior, and a pressure port for removing fluid from the interior. The impeller is indoors and includes a plurality of impellers for converting impeller motion energy to fluid pressure energy into a pressure port. The Kie Rye Housing is arranged to surround the impeller. The impeller is mounted on a drive shaft 35 which is rotatably mounted on a frame. The drive shaft is rotated by the drive motor.

3

A number of pumps are used in parallel to provide the required volume flow rate. Typically, there are two pumps in use, with two pumps being in addition for maintenance. The cost of these pumps and the auxiliary equipment required represents a significant proportion of the total investment cost of the plant.

In liquid-liquid extraction processes, care should be taken to handle the organic extraction solution as gently as possible because mixing and pumping affect the physical and chemical properties of the solution. As the solution is pumped or agitated at high impeller circumferential speeds, such as occurs with conventional centrifugal pumps, shear forces are applied to the liquid, thereby reducing the size of the aqueous droplet residues or completely blocked. Thus, water droplets and the soluble impurities contained therein can be carried along the leaching solution through the clarification basins throughout the process, down to the product of the process, impairing its quality and commercial value.

Further, the fluid to be pumped may contain small solids particles or colloids. In metal refining processes, solids often come from soluble ore or concentrate in solutions. In this case, the centrifugal pump shear forces can cause extraction fines, the so-called. crudie formation. Crud is a stable structure of an organic extraction solution, an aqueous solution, and a solid that accumulates at the clarification basins of the extraction cells at the interfaces of the aqueous and organic phases. When the crud number 35 exceeds a certain limit, it must be removed from the system. Crud binds the expensive 4 reagents contained in the leach solution, which causes an increase in operating costs for the plant.

PURPOSE OF THE INVENTION

The object of the invention is to eliminate the above-mentioned drawbacks.

In particular, it is an object of the present invention to provide a new type of pump which handles the pumped so gently that the physical and chemical properties of the pum-10 stopping fluid are not affected by the pumping.

It is a further object to provide a pump particularly suitable for use in a hydro-metallurgical recovery process of metals for pumping an organic extraction solution between an extraction solution tank and an extraction process to replace a plurality of separate centrifugal pumps commonly used with a single pump of the invention.

It is a further object of the invention to provide a pump which does not adversely affect the physical and chemical properties of the leach solution to be pumped.

SUMMARY OF THE INVENTION

The pump of the invention is characterized in what is set forth in claim 1. The method of disassembling the pump according to the invention is characterized in that set forth in claim 13.

According to the invention, the body is a cylindrical vertical container that is open upwardly, the interior of which is bounded downward by a substantially horizontal planar bottom having a central circular suction port, and the interior enclosed by a lateral first side wall with a depression near the bottom. The impeller 5 is arranged to rotate about a vertical axis in a horizontal position in the immediate vicinity of the inlet and centrally with respect to the container. The pump includes a recessed lid centrally disposed within the inner space of the container and having a cylindrical vertical second sidewall having an outer diameter smaller than the inside diameter of the first sidewall so that an upwardly open annular first space is formed between the first sidewall and the second sidewall. . Further, the pump comprises a bottom cone which is frustoconical in shape and extends downwardly tapering in the vicinity of the impeller; and a vertical lead-through pipe extending vertically upwardly from the base cone, on which a drive shaft is disposed, and within which the lead-through tube is surrounded by an upwardly open second space. Further, the pump includes a vertical helical wall which surrounds the impeller, forming, together with the base cone, a helical housing partially enclosing the impeller and extending towards the pressure port. The helical wall extends in radius of bending from a first end proximal to the impeller outer periphery to a proximal second end of the first sidewall of the container, and wherein the first end has a baffle to direct fluid flow to the pressure port. The plunger cap closes the free liquid surface of the fluid in the reservoir so that as the impeller rotates into said first and second spaces, a liquid column is formed to convert a portion of the pressure energy of the fluid into a potential energy hydrostat to create pressure in the pressure port.

In one embodiment of the pump, the impeller comprises a horizontal circular top plate fixed to the drive shaft and to which the top plate curved impellers 35 are attached at their top edge; an annular lower plate having a circular inlet centered centrally with respect to the suction port for receiving fluid into the impeller through the inlet port, and to the lower plate with impellers at its lower edge surrounding the circumferential lower plate inlet and through the vane impeller 5 for fluid delivery.

In one embodiment of the pump, the helical wall is secured to a recessed cover, preferably to a bottom cone.

In one embodiment of the pump, the pump is a pump for use in a fluid-10 fluid extraction process for metal hydrometallurgical recovery.

In one embodiment of the pump, the pump is a pump connected to an extraction solution equalization tank.

In one embodiment of the pump, the pump is a pump between the extraction solution expansion tank and the mixer-settler cell.

In one embodiment of the pump, the pump yield is between 10 and 10,000 m3 / h.

In one embodiment of the pump, the pressure produced by the pump is in the order of 500 to 1200 mm H 2 O.

In one embodiment of the pump, the pump is adapted to pump solutions typically having a density of 0.7 to 1.2 kg / dm3 and a dynamic viscosity of 1 to 8 mPas.

In one embodiment of the pump, the pump is constructed of a material which is highly corrosive to corrosive aqueous solutions and chemically aggressive organic solutions.

In one embodiment of the pump, the reservoir, the sink, the impeller and / or the helical wall are formed of acid-proof steel.

In one embodiment of the pump, the reservoir, sink, impeller and / or helical wall are formed of fiber-reinforced plastic.

The method of disassembling the pump comprises forming a submerged lid, helical wall, impeller, drive shaft, and drive motor into a subassembly that can be treated as a single unit. To disassemble the pump, said subassembly is removed and lifted as a unit out of the interior of the container without having to remove the container from the piping to which the container is connected and without having to remove fluid from the container.

5 In the method, a rotary impeller of a centrifugal pump is used to convert the kinetic energy into the pressure energy of the fluid. Some of the pressure energy provided by the impeller is directly converted to the pressure energy on the pressure side of the pump, and a part of the fluid column formed by the impeller 10 rotates to potential energy to provide the hydrostatic pressure on the pump side.

In one embodiment of the method, the surface of the fluid to be pumped in the suction tank 15 is arranged at such a height that the fluid completely covers the impeller.

In one embodiment of the method, the liquid pressure at the suction side is provided positive during pump operation.

20, in one embodiment, the method provides for controlling the rotational speed of the output of the pump impeller when the level of pumped liquid in the container on the suction side varies and / or when the pressure side varies.

In one embodiment of the method, the volume flow rate of the fluid to be pumped is measured and the impeller rotation speed is adjusted based on the measured value.

In one embodiment of the method, the rotation speed of the impeller is adjusted such that the circumferential velocity of the impeller is in the order of 3.5 to 4.5 m / s.

The pump of the invention can pump an organic extraction solution during hydrometallurgical recovery of metals so that the extraction solution is subjected to lower shear forces than when pumped by a centrifugal pump.

With one pumping unit according to the invention, the 8 volumes of leach solution volume required for the whole leaching process can be pumped and thus the conventionally used parallel leachate pumps of the leach solution equalizer can be replaced. The pump may also be located elsewhere in the liquid-liquid extraction process, which requires a high volume flow at a relatively low pressure output.

According to experience with pumping units of a similar type in a mixer settler, the pump can be freely dimensioned and built to a desired flow rate of 10 to 10,000 m3 / h over a wide range. The pressure generated by the pump is typically relatively low, from 500 to 1200 mmH 2 O, however sufficient for a hydrometallurgical liquid-liquid extraction process designed to contain the same amount of ferric material. The apparatus is used to pump solutions in extraction plants, which typically have a density of 0.7 to 1.2 kg / dm3 and a dynamic viscosity of 1 to 8 mPas.

2 0 LIST OF PHOTOS

The invention will now be described in more detail by way of example with reference to the accompanying drawing, in which Figure 1 is a schematic side elevational view of an embodiment of a pump according to the invention; Figure 2 is a section II-II in Figure 1; Fig. 4 is a side view of the impeller and its drive shaft of Fig. 1, Fig. 6 is a side elevation view of Fig. 3, Fig. 5 is a side elevation of Fig. 3, Fig. Fig. 6 is a view of the impeller shown in the direction VII-VII in Fig. 6, Fig. 8 is a sectional view of VIII-VIII in Fig. 7, Fig. 9 is a sectional view of IX-IX in Fig. 8, Fig. 10 is a pump connected to a fluid reservoir , and Fig. 11 shows a 10 m view the subassembly A of the Ukrainian system when removed and lifted out of the container.

DETAILED DESCRIPTION OF THE INVENTION

Figure 1 illustrates a pump designed specifically for use in a liquid-liquid extraction process for metal hydrometallurgical recovery, but also suitable for any other application where the pump is required to handle the fluid gently without exerting excessive shear forces on the liquid and chemical properties.

The pump may be, for example, a pump between a flat tank of extraction solution and a mixer-settler cell. In the liquid-liquid extraction process, the volume flow generated by the pump is typically in the range of 10 to 10,000 m3 / h and the pressure produced by the pump is in the order of 500 to 1200 mm H 2 O. In particular, the pump is adapted to pump extraction solutions of the liquid-liquid extraction process, typically having a density of 0.7 to 1.2 kg / dm3 and a viscosity of dy-30 of 1-8 mPas. The pump is constructed of a highly corrosive aqueous and chemically aggressive organic solution resistant material such as acid-proof steel or fiber-reinforced plastic.

The pump body 1 is a cylindrical, vertical, upwardly open container 10 whose interior 2 is limited downwardly by a substantially horizontal planar base 11 having a central circular suction port 3. Laterally, the interior of the container 10 is limited by a vertical first side wall 12 having a bottom 11 in the vicinity, there is a pressure port 4.

The impeller 5, which is rotated by the drive motor 9 through the vertical drive shaft 8, is arranged to rotate about the vertical axis in a horizontal position in the immediate vicinity of the suction opening 3 and a few millimeters away therefrom.

Referring to Figures 1, 2 and 4, the pump further comprises a plunger cover 13 centrally disposed within the interior of the container 10. The plunger cover 13 includes a cylindrical vertical second side wall 14 having an outer diameter smaller than the inside diameter of the first side wall 12 so that an upwardly open annular first space 15 is formed between the first side wall 12 of the container and the second side wall 14 of the plunger. to the flange of the upper end. The recessed cover 13 includes a bottom cone 16 extending from the lower end of the second side wall 14, which is in the form of a truncated circular cone and extends downwardly convergingly to the impeller 5. In the center of the plunger cover 13 is a vertical lead-through conduit 17 which extends upwardly from the bottom cone 16 and within which the drive shaft 8 is arranged. Inside the lead-through tube 17 about the drive shaft 8, an upwardly open second space 18 is defined.

The vertical helical wall 19 surrounding the impeller 5 together with the bottom cone 16 forms a helical housing 7 partially surrounding the impeller 5, extending towards the pressure port 4, the horizontal lower edge of the helical wall 19 resting against the bottom 11 of the container 10. The helical wall 19 extends radially from its first end proximal to the impeller outer periphery 20 to the second second end 21 of the first side wall 12 of the container. The first end 20 has a baffle 22 for directing fluid flow to the pressure port 4.

The plunger cap 13 closes the free liquid surface of the liquid in the container 10 such that a fluid column 27 is formed as the impeller 5 rotates into first space 15 and second space 18. Some of the fluid energy in the fluid 27 is converted into potential energy.

Figures 6-9 show in greater detail the structure of the impeller 5 10. The impeller 5 is similar in design to a closed-ended turbine used in centrifugal pumps. The impeller 5 comprises a horizontal circular top plate 23 attached to the drive shaft 8. The curved impellers 6 are secured at the top to a circular top plate 23. The impellers 6 are secured at the bottom to an annular bottom plate 24 having a circular inlet 25 in the center. aligned with suction opening 3 to receive fluid into impeller 5 through inlet 25 20. The impellers 6 circumferentially outwardly curve the inlet 25 of the lower plate and form a blade passage 26 through which the fluid exits from the inside of the impeller to the worm body 7 surrounding the impeller.

As shown in Figure 3, the helical wall 19 is preferably secured to a recessed cover 13, preferably to a bottom cone 16.

The pressure port 4 from which the pumped solution discharges into the pipeline is located on the side of the tank 10 at the same level as the bottom 11 of the tank. The pump connects to its pressure port 30 through a piping system whose back pressure is dimensioned to match the pressure produced by the pump. Applying a pump to a metal hydrometallurgical liquid-liquid extraction recovery process, the device typically pumps the extraction solution to the subsequent pumping portion of the 35 mixer-settler cells.

As illustrated in Figure 11, its design allows the pump to be easily dismantled, if necessary, by disassembling and lifting the submerged cover 13, helical wall 19, impeller 5, drive shaft 8 and drive motor 9 into the subassembly A without having to remove the tank 5 from the piping. . In this case, the solution in the container 10 can also be left in place.

Referring to Figure 10, the pump operates such that the fluid to be pumped enters the pump reservoir 10 through suction port 3 into pump impeller 5 and its impeller 26. 10 As impeller 5 rotates, it displaces fluid, causing suction at pump suction port 3 and engaging tangentially in a state where the solution is directed towards the pressure port 4 of the pump. 15 The mechanical energy provided by the impeller 5 is converted into the pressure energy of the solution. Part of this is directly converted into fluid energy of motion and partly converted into potential energy when a liquid column 27 is formed in the upwardly open tank of a pump whose height causes the hydrostatic pressure in the pump port 4. The plunger cap 13 closes the free liquid surface of the pump container so that when the pump is running and raising the fluid pressure, the liquid surface is freely raised and lowered in the narrow en-25 first space 15 between the plunger 13 and the tank 10 and inside the drive shaft 8 of the impeller 5.

The suction side of the pump is connected by a tube to a tank 28 from which fluid is pumped. The surface of the pumped liquid must be on the suction side at a height such that the pump impeller is completely covered by the liquid. Even with the pump running, the solution pressure in the suction duct must be positive. The pump flow rate is adjusted by adjusting the pump rotation speed when the level of the fluid to be pumped on the suction side varies or when the back pressure varies. The control system operates with a flow measurement sensor connected via a controller to a frequency converter controlling the speed of the pump motor.

The impeller rotation speed of the pump is such that the impeller peripheral speed is typically of the order of 3.5 to 4.5 m / s. Hereby, the shear forces on the liquid are relatively low and their adverse effects on the extraction solution are avoided.

The invention is not limited to the above embodiments only, but many modifications are possible within the scope of the inventive idea defined by the claims.

Claims (13)

A pump for pumping fluid comprising: - a housing (1) having a hollow interior (2), 5. a suction port (3) for allowing fluid to enter the interior (2), - a pressure port (4) for removing fluid from the interior (2), - an impeller (5) indoors and comprising a plurality of impellers (6) for converting the impeller motion energy into fluid pressure energy into a pressure port, a helical housing (7) arranged to surround the impeller, the 15th drive shaft (8), to which the impeller is mounted and mounted rotatably on the housing, and - the drive motor (9) for rotating the drive shaft, characterized in that the housing (1) is a cylindrical vertical container (10) which is open upwards and has an interior (2). defined downwardly by a substantially horizontal planar base (11) having a central circular suction opening (3), the interior of which is laterally limited by a vertical first-side sidewall (12) having a bottom (11) ) in the vicinity there is a pressure outlet (4); that the impeller (5) is arranged to rotate about a vertical axis in a horizontal position in the immediate vicinity of the inlet (3) and centrally with respect to the container (10), and that the pump 30 includes: a plunger (13) centrally disposed in the interior (2) the recessed cover includes a cylindrical vertical second side wall (14) having an outer diameter smaller than the inner diameter of the first side wall (12) so that an upwardly open annular first space (15) / bottom cone (16) is formed between the first side wall and the second side wall. truncated cone-shaped and extending downwardly convergingly in the vicinity of the impeller (5); and a vertical lead-through conduit (17) extending vertically upwardly from the base conveyor 5, within which a drive shaft (8) is arranged and a second open space (18) bordering upwardly on the drive shaft about the drive shaft, and (19), which 10 surrounds the impeller (5), together with the base cone (16), forming a helical housing (7) extending partially towards the impeller (5) extending towards the pressure port (4) and extending radially from the outer circumference of the impeller from (20) to a second second end (21) near the first side wall of the container, and wherein the first end (20) has a baffle (22) for directing the flow of fluid into the pressure port (4). A pump according to claim 1, characterized in that the impeller (5) comprises a horizontal circular top plate (23) attached to the drive shaft (8) and to which the top plate has curved impellers (6) at its upper edge; an annular lower plate (24) having a central inlet 25-center (25) centrally relative to the inlet (3) for receiving fluid into the impeller through the inlet, wherein the lower plate has impellers at its lower edge circumferentially surrounding the lower plate inlet (25) and forming a vane impeller (26) through which the fluid exits from the inside of the impeller to the worm housing (7). A pump according to claim 1 or 2, characterized in that the helical wall (19) is attached to the plunger cover (13), preferably to the bottom cone (16). A pump according to any one of claims 1 to 3, characterized in that the pump is a pump for use in the liquid-liquid extraction process of metals by hydrometallurgical recovery. 5. A pump according to claim 4, characterized in that the pump is a pump connected to a flat tank of leach solution. A pump according to claim 4 or 5, characterized in that the pump is a pump between the leach solution settling tank and the mixer-settler cell. Pump according to one of Claims 1 to 6, characterized in that the pump output is between 10 and 10,000 m3 / h. Pump according to one of Claims 1 to 7, characterized in that the pressure produced by the pump is in the order of 500 to 1200 mm H 2 O. A pump according to any one of claims 1 to 8, characterized in that the pump is adapted to pump solutions typically having a density of 0.7 to 1.2 kg / dm3 and a dynamic viscosity of 1 to 8 mPas. A pump according to any one of claims 1 to 9, characterized in that the pump is constructed of a substance which is highly corrosive to aqueous corrosives and chemically aggressive organic solutions. Pump according to one of Claims 1 to 10, characterized in that the reservoir (10), the sink cover (13), the impeller (5) and / or the helical wall (19) are made of acid-proof steel. Pump according to one of Claims 1 to 11, characterized in that the reservoir (10), the recessed lid (13), the impeller (5) and / or the helical wall (19) are made of fiber-reinforced plastic. Method for dismantling a pump according to one of claims 1 to 12, characterized in that the countersunk cover (13), the helical wall (19), the impeller (5), the drive shaft (8) and the drive motor (9) are subassembled (A). which can be handled as a single unit, and to disassemble the pump, said subassembly (A) is removed and lifted as a single unit from the interior (2) of the tank (10) without having to remove the tank from the piping to which the tank 5 is connected.