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Publication numberUS3902858 A
Publication typeGrant
Publication dateSep 2, 1975
Filing dateJan 4, 1974
Priority dateJan 4, 1974
Publication numberUS 3902858 A, US 3902858A, US-A-3902858, US3902858 A, US3902858A
InventorsChernykh Vitaly Petrovich
Original AssigneeChernykh Vitaly Petrovich
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Chemical production processing unit
US 3902858 A
Abstract
A chemical production processing unit comprising an externally heated autoclave. The autoclave cover is provided with a hole for charging a heterogeneous system. A hollow housing is rotatably mounted on the autoclave cover and is externally provided with blades for stirring the heterogeneous system and internally provided with a helical groove. A pipe for discharging the heterogeneous system is accommodated in the autoclave bottom in such a manner that the inlet opening of the pipe is located above the maximum admissible level of the liquid phase of the heterogeneous system in the autoclave.
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United States Patent Chernykh [4 1 Sept. 2, 1975 CHEMICAL PRODUCTION PROCESSING UNIT Inventor: Vitaly Petrovlch Chernykh, ulitsa Kurchutova, 9, kv. 4, Irkutsk.

U.S.S.R.

Filed: Jan. 4, 1974 Appl. No.: 430,612

US. Cl. 23/290; 210/413; 210/393; 210/408; 259/7; 259/8; 259/43; 259/44', 259/107; 259/108 Int. Cl. .Q 501.] 3/04 Field of Search 23/285, 290, 290.5, 260; 210/413, 414, 415, 393, 408; 259/7, 8, 43,

Reierences Cited UNITED STATES PATENTS v III Illilllll lll.

FOREIGN PATENTS OR APPLICATIONS 983,477 2/1965 United Kingdom 259/7 26.398 12/1955 Germany ..259/8 Primary Examiner-JamesH. Tayman, Jr. Attorney, Agent, or Firm-Waters, Schwartz & Nissen [57] ABSTRACT A chemical production processing unit comprising an externally heated autoclave. The autoclave cover is provided with a hole for charging a heterogeneous system. A hollow housing is rotatably mounted on the autoclave cover and is externally provided with blades for stirring the heterogeneous system and internally provided with a helical groove. A pipe for discharging the heterogeneous system is accommodated in the autoclave bottom in such a manner that the inlet opening of the pipe is located above the maximum admissible level of the liquid phase of the heterogeneous system in the autoclave.

10 Claims, 3 Drawing Figure s PATENTEDSEP I 3 902 858 SHEET 1 1F 3 F/EJ . PATENTEBSEP 2|975 CHEMICAL PRODUCTION PROCESSING UNIT The present invention relates to the equipment for conducting chemical production processes, and more particularly it is concerned with a chemical production processing unit.

The present invention may be the most advantageously used in leaching aluminium from bauxites, extracting nickel and cobalt from suplhide concentrates by the Sherrit-Gordon method and in extracting uranium from mineral concentrates.

Known in the art is a chemical production processing unit which is used in particular in leaching aluminium from bauxites. The unit includes a heated autoclave. The autoclave comprises a hermetically sealed housing. The housing cover is provided with a hole for charging a pulp. The pulp is discharged through the overflow pipe accommodated in the autoclave cover. Mounted in the bottom plate of the autoclave is a pipe for supplying steam under pressure into the autoclave which is fed directly into the pulp. The steam is used to heat and agitate the pulp. The pulp is pumped into the autoclave by means of a piston pump. The stirring of the pulp is effected by injecting steam through the pulp stratum. The pulp is expelled through the overflow pipe under the steam pressure.

In the known unit for leaching of aluminium from bauxites there is no intensive stirring, whereby the duration of the leaching process is increased, and the yield of the aluminium extraction is reduced. This unit is unsuitable for processing heavy abrasive pulps and aggressive media due to the difficulties encountered in pumping of heavy abrasive pulps by means of a piston pump and in their discharging through the overflow pipe. The pump rapidly fails, the seals are subject to excessive wear. Heavy abrasive medium clogges the overflow pipe. The stirring of the pulp with steam is inadmissible for such chemical production process as the extraction of tantalum and niobium from mineral concentrates since water is undesirable component is this case. The above-described processing unit has low yield of extraction of valuable components from the pulp since a part of the pulp present in the overflow pipe takes no part in the leaching process. The pulp cannot be completely discharged from the autoclave since the overflow pipe should be spaced at a certain distance from the bottom plate of the autoclave to ensure the hermetical sealing of the autoclave and to prevent the overflow pipe from clogging with the solid components of the pulp, since the accumulation of mud takes place in the bottom portion. Furthermore, the continuous mode of operation during the conduct of the chemical production process is maintained only by having a battery of autoclaves, as well as by using delivery pumps and continuous steam supply.

Known in the art is also a chemical production processing unit to be used e.g., in leaching aluminium from bauxites. This unit comprises an externally heated autoclave. The autoclave housing is heated by an electric heater. The autoclave cover is provided with a hole for charging the pulp being processed. The pulp is stirred by a propeller agitator driven by an electric motor via a reduction gear. The processed pulp is discharged through an overflow pipe secured in the autoclave cover.

The use of the overflow pipe for discharging the processed pulp cannot ensure the complete discharge since in order to have a space for rotation of the propeller agitator and to ensure the hermetical sealing of the assembly housing-cover, the overflow pipe should be spaced at a certain distance from the autoclave bottom plate. In addition, the overflow pipe is unsuitable for discharging heavy, and especially coarse-grained pulps since in this case the precipitation of the solid phase takes place with clogging of the pipe. During the stirring of the pulp in the autoclave the pulp remains immobilized in the overflow pipe and practically is not leached, thereby resulting in reduced yield of aluminium extraction. The autoclave having the overflow pipe for the pulp discharge is inconvenient in operation when inserted in the production line of equipment intended for performance of a continuous process, such as for conducting continuous processing of sulphide copper-nickel-cobalt concentrates by the Sherrit- Gordon method since there is no opportunity of controlling the amount of pulp passing through the autoclave. The discharge of the processed pulp from the autoclave through the overflow pipe can be effected only under the pressure of a vapour and gas medium in the autoclave or due to the use of an independent external pressure source. This is not convenient where the autoclave is to be used for conducting the intermittent processing since the pressure of a steam-gas medium is associated with high temperature thereof, and hence the discharge of the processed pulp from the autoclave is dangerous due to the risk of expulsion of the entire content thereof. Generally the autoclave is cooled at room temperature, and then compressed gas is fed to expell the processed pulp through the overflow pipe. Such method of discharging the pulp is associated with additional power consumption for obtaining compressed gas.

It is an object of the invention to improve the efficiency of operation of a chemical production processing unit due to improved conditions of stirring and discharging of a heterogeneous system processed therein.

It is another object of the invention to improve the yield of extraction of valuable elements from the heterogeneous system.

Still another object of the invention is to improve the productivity of the chemical production processing unit and the quality of the desired product.

Finally, it is an object of the invention to reduce the time spent for preparatory operations, such as cleaning and washing associated with the transition to a new chemical production process.

In accordance with the above and other objects, the present invention consists of a chemical production processing unit comprising an externally heated autoclave having a hole for charging a heterogeneous system composed of liquid, solid and gaseous components, said holebeing arranged in the autoclave cover, and means for stirring the heterogeneous system. According to the invention said means for stirring the heterogeneous system comprises a hollow housing rotatably mounted on the autoclave cover, said housing being externally provided with stirring blades and internally provided with a helical groove, said housing enclosing a pipe for discharging the processed heterogeneous system accommodated in the bottom plate of the autoclave in such a manner that the inlet opening of the pipe is located above the maximum admissible level of the liquid phase of the heterogeneous system in the autoclave.

Such embodiment of the chemical production processing unit makes it possible to effect an intensive stirring of the entire volume of the pulp charged into the autoclave since the pulp contained in an annular space formed between the inner surface of the housing and the outer surface of the pipe for discharging the pulp is intensively stirred and hence leached. This results in improved yield of extraction of valuable elements from the pulp, that is in reduced content of valuable element in the leaching cakes. In addition, the above-described unit ensures reliable and more complete discharge of the pulp from the autoclave, and the degree of utilization of the working space of the autoclave is thereby improved.- The unit enables the continuous autoclave processing under high pressure since it is readily insertable in the line of the continuously operating equipment. The pulp stirring without its discharge can be effected in this unit, as well as the pulp discharge without stirring thereof. The unit enables considerable reduction of the time spent for preparatory operations in the batch processing autoclaves, such as for cleaning, washing and assembly of the autoclave.

The hollow housing should preferably enclose the pipe for discharging the heterogeneous system so as to form an annular space between the outer surface of the pipe and the inner surface of the housing.

Where the pipe for discharging the heterogeneous system is excentrically arranged relative to the hollow housing, the productivity of the autoclave is abruptly decreased during the discharge of the heterogeneous system since only a part of the groove on one side of the housing takes part in the operation. In addition, power consumption is increased due to the maceration of solid components of the heterogeneous system between the interengaging surfaces of the hollow housing and pipe for discharging the heterogeneous system, the service life of the pipe for discharging the heterogeneous system and of the hollow housing is reduced, and additional circulatory losses appear which result in decreased productivity of the autoclave during the discharge of the processed heterogeneous system.

The helical groove on the inner surface of the hollow housing preferably extends only over the portion of the entrance of the heterogeneous system into the hollow housing.

This results in reduced power consumption for overcoming the force of attrition between the abrasive particles of the heterogeneous system and the helical groove during the pumping of the heterogeneous system from the bottom part of the autoclave.

The inner space of the pipe for discharging the heterogeneous system is preferably communicated with the vapourand gas-containing space of the autoclave by means of a control valve.

The communication of the inner space of the pipe for discharging the heterogeneous system with the vaporand gas-containing space of the autoclave by means of a control valve ensures a flexible and smooth discharge with the control of the amount of the heterogeneous medium being discharged over a wide range. This is especially important in conducting the continuous autoclave processing, where the autoclave is inserted in the line of equipment operating under high pressure.

The direction of the helical groove is preferably opposite to the rotational direction of the hollow housing so as to ensure the stirring of the heterogeneous system without discharging it.

For discharging the heterogeneous system the direction of the helical groove in the hollow housing should preferably coincide with that of the rotation of the hollow housing.

Other objects and advantages of the invention will become apparent from the following detailed description of a specific embodiment thereof with reference to the accompanying drawings, in which:

FIG. 1 shows a diagrammatic general view of a chemical production processing unit according to the invention;

FIG. 2 shows a partial enlarged longitudinal section of an autoclave according to the invention having means for stirring and discharging the heterogeneous system;

FIG. 3 shows the bottom portion of the autoclave with means for discharging a solution of the heterogeneous system and a sampler for liquid products.

The leaching of aluminium from bauxites also represents the chemical production process.

The unit for leaching aluminium from bauxites comprises an autoclave 1 (FIG. 1) and an electric heater 2 providing the heating of the autoclave 1. The electric heater 2 is closed by a heat insulating casing 3. For convenient operation the autoclave 1 is mounted on a support 4 which is vertically movable along a guide frame 5 made from tubes in the form of a parallelepiped and can be fixed on the frame in a desired position. The use of the frame 5 ensures better conditions for assembly of the autoclave 1 during its maintenance and permits the positioning of the autoclave during the operation at a desired level above the floor or to dispose the group of the autoclave in the aligned position, as well as in the form of a multi-storage plant for operation under gravity and for ensuring complete discharge of the pulp from the communication conduits. The autoclave 1 compries a hermetically sealed receptacle and is provided with a removable cover 6 supporting a seal 7 of a shaft 8 of means for stirring the pulp which constitutes a heterogeneous system. The pulp consists of finely divided bauxite and aqueous solution of caustic soda. The pulp is charged into the autoclave 1 through a hole 9 made in the cover 6. In addition, the cover 6 has an opening for accommodation of a pipe 10 (FIG. 2) having a soldered end for a thermocouple (not shown in the drawings) for measuring the pulp temperature. For monitoring the performance of the production process of leaching of bauxites, a sampler 11 for vapour and gas phase is mounted in the cover 6 (FIG. 1), while a sampler 13 for liquid phase is mounted in a bottom plate 12 (FIG. 2) of the autoclave 1. Means for stirring the pulp comprises a hollow housing 14 (FIG. 2) attached to the shaft 8 which is driven by an electric motor 15 (FIG. 1) mounted on the cover 6 of the autoclave 1. The hollow housing 14 (FIG. 2) is externally provided with blades 16 for stirring the pulp, while the inner surface of the housing is provided with a helical groove 17 which may extend only over the portion of the pulp entrance so as to reduce power consumption due to the attrition of the abrasive particles of the pulp. The lower end of the hollow housing 14 is spaced at a distance of several millimeters from the bottom plate 12 of the autoclave 1. A pipe 18 is accommodated in the bottom plate 12 for pulp discharge so that its inlet opening is located above the maximum admissible level of liquid phase, of the pulp in the autoclave 1, such as the solution of caustic soda. The hollow housing. 14 encloses the pipe 18 so that an annular space 19 is formed between the outer surface of the pipe 18 and the inner surface of the housing 14. A multiple filter is mounted in the bottom plate 12 so as to ensure the production of clean sodium aluminate solution. The multiple filter consists of three filters. A lower coarse filter 20 is made of stainless steel by the powder metallurgy method.

The filter 20'is enclosed with its outer periphery into a metallic ring 21, while theinner periphery ofthe filter embraces a ring 22. The rings'21and 22 prevent nonfiltered pulp from leaking egg-into a receptacle for the solutionby-passing a filter 23. The upper filter 20 is snug fitted atthe level of the bottom plate 12. This is important in order to'eliminate-the formation of dead spaces," that is of the spaces with bad'agitati'on and circulation of the pulp. The filter 20.protects against mechanical damage a fine filter 23, which is made of asbestos paper and ensures fine purification of liquid phase of the pulp, such as caustic soda solution. A

lower fine filter 24 is made of stainless steel powder by the powder metallurgymethod. This filter constitutes the support for the filter 23 and protects it against breaking-through during the pulp filtering under high pressure. The filter 23 is sealed by a gasket 25 made of asbestos paper. Such multiple filter' is chemically and thermally resistantagainst the action of aggressive medium at high temperature. The pulp can be discharged from the autoclave 1 by using ,the pressure of vapour andgas medium. In order to provide for flexible and smooth control of the amount ,of the pulp being discharged, the inner space 26 of thepipe l8 communicates with the vapourand gas-containing space of the autoclave l by means of a conduit 27 through a control valve 28. i

The outlet opening of the pipe 18 is closed by a plug 29 (FIG. 3) where the autoclave is used for the intermittent processing.

A vertically extending passage 30 is provided in the wall of the pipe 18 to discharge the sodium aluminate filtrate. The passage 30 communicates with an annular space 31 disposed above the multiple filter for collecting filtered sodium aluminate, and also communicates with the sampler 13' via a valve 32.

The sampler 11 (FIG. 1) for gaseous phase comminicatess with the vapourand gas-containing space of the autoclave l by means of a valve 33.

The unit is intended for conducting an intermittent chemical production process, such as leaching of aluminium from bauxites and functions as follows:

A pulp composed of finely divided bauxite and an aqueous solution of caustic soda (NaOH) is charged into the assembled autoclave (FIG. 1) through the hole 9.

The hole 9 is then tightly sealed. The electric heater 2 is energized, and the content of the autoclave l is heated at a required temperature (about 230C) so that a vapour and gas medium is formed within the autoclave 1. Upon the achievement of a desired temperature the electric motor is energized. In so doing, in order to ensure an intensive stirring of the pulp, the hollow housing 14 (FIG. 2) is to be rotated in the direction opposite to the direction of the helical groove 17.

During the rotation of the hollow housing 14 the pulp is stirred. The pulp is subjected to leaching for a desired time period (about 2-3 hours).

After the leaching has been completed, the entire volume of the solution is filtered under the pressure of the vapour and gas medium, which is formed in the autoclave 1. Then the sampler 13 (FIG. 3) is removed, and a receptacle (not shown) is connected to the autoclave 1. The valve 32 is opened, and the solution of sodium aluminate is collected from the autoclave 1 through the filters 20, 23 and 24 in the annular space 31, wherefrom the solution is discharged into the receptacle. Then the valve 32 is closed, and the receptacle is disconnected from the autoclave 1. Waste ore remaining on the filter 20 is referred to as cake. In order to remove the cake from the autoclave 1, water is poured into the autoclave through the hole 9 (FIG. 1) or through the valve 32 (FIG. 3). Then the electric motor 15 is energized. The hollow housing 14 with the blades 16 will thoroughly agitate the cake with water. The plug 18 is then removed from the pipe 18. The rotational direction of the hollow housing 14 is analogous with the direction of the helical groove 17, and the rotating hollow housing 14 operates as a screw pump in combination with the pipe 18. The cake with water are discharged through the inner space 26 of the pipe 18. The autoclave 1 is then washed with fresh water, and the pipe 18 is closed with the plug 29. The autoclave l is now ready for a new cycle of operation.

In conducting a continuous chemical production process, such as in the autoclave leaching of sulphide copper-nickel-cobalt concentrate by the Sherrit-Gordon method the autoclave l is mounted in the line of the equipment consisting of several autoclaves, receptacles, filters, centrifuges and other continuous-action apparatus (not shown in the drawings).

A conduit from a distribution tank with a pulp or a conduit of a pulp delivery pump (not shown in the drawings) is connected to the flange of the hole 9. The plug 29 is removed from the pipe 18 (FIG. 3) and the latter is connected to a conduit leading to a next unit, for instance to a similar autoclave or to a receiving tank (not shown in the drawings).

A pulp consisting of sulphide concentrate, water, ammonia and air oxygen is continuously fed into the autoclave 1 through a conduit (not shown) and the hole 9 (FIG. 1).

The electric heater 2 is energized, and the autoclave l with the pulp is heated at a desired temperature.

Then the electric motor 15 is energized so that the rotational direction of the hollow housing 14 (FIG. 2) should be analogous with the direction of the helical groove 17. The intensive stirring of the pulp takes place, and the leaching process begins.

Under steady operating conditions the pulp is continuously fed into the autoclave 1 through a conduit (not shown) and the hole 9 (FIG. 1). The pulp is leached and concurrently continuously discharged through the inner space 26 of the pipe 18 (FIG. 2) from the autoclave for feeding into a next unit.

The control valve 28 in the conduit 27 communicating the inner space 26 of the pipe 18 with the vapourand gas-containing space of the autoclave 1 is adjusted to pass such an amount of the vapour and gas medium that the amount of the pulp discharged through the pipe 18 and the pressure of the vapour and gas medium in the autoclave 1 should correspond to the leaching rate. During the continuous leaching the conduct of the production process is monitored. For that purpose the valve 32 is opened (FIG. 3), and the solution is fed through the passage 30 into the sampler 13, while in order to check the conditions of the gaseous phase, the valve 33 is opened (FIG. 2), and gas is fed into the sampler l 1.

During the leaching the pulp temperature is monitored by means of the thermocouple mounted in the pipe 10 (FIG. 2).

In the case of troubles in the process of leaching the pulp discharge from the autoclave 1 should be interrupted. For that purpose the control valve is completely opened. The hollow housing 14 is rotated in the direction opposite to the direction of the helicalgroove 17. In that case the leaching process can be conducted in the autoclave for a longer time until complete extraction of valuable elements from the pulp, and only after that the pulp discharge can be again restored for feeding the pulp into a next unit of the production line.

Where it is desired to accelerate the pulp discharge from the autoclave l, the control valve 28 is almost completely closed or shut-off, and the rotational direction of the hollow housing 14 should in this case be analogous with the direction of the helical groove 17 for discharging the pulp.

What is claimed is:

l. A chemical production processing unit comprising: an externally heated autoclave; a cover of said autoclave with a hole for charging a of a heterogeneous system consisting of solid, liquid and gaseous components; a bottom plate of said autoclave with a pipe for discharging the heterogeneous system accommodated in said bottom plate so that the inlet opening of said pipe is located above the highest admissible level of the liquid phase of the heterogeneous system in said autoclave; an annular projection with an annular recess on said pipe; a hollow housing rotatably mounted in said cover of said autoclave, said housing having internally a helical groove and enclosing said pipe for discharging the heterogeneous system; blades on the, external surface of said hollow housing for stirring the heterogeneous system; a device for controlling the discharging of the heterogeneous system in the form of a pipe, one end of said pipe communicating with the space of said pipe for discharging the heterogeneous system located below said hollow housing, and the other end of said pipe communicating with the vapor-gas space of said autoclave, said two pipes forming communicating vessels; a filtering device mounted in the bottom plate of said autoclave and supported by the annular projection of said pipe for discharging the heterogeneous system and consisting of a set of coarse-pore and fine-pore filtering elements forming together with said annular recess an annular cavity communicating with the passage for discharge of the filtrate from said autoclave and for the supply of blow gas thereto.

2. A unit according to claim- 1, wherein said hollow housing encloses. said pipe for discharging the heterogeneous system in such a manner that an annular space is formed between the outer surface of said pipe and the inner surface of said hollow housing.

3. A unit according to claim 1, wherein said helical groove on said inner surface of said hollow housing extends over the portion of the entrance of the heterogenous system into said hollow housing. I

4. A unit according to claim 2, wherein said helical groove on said inner surface of said hollow housing extends over the portion of the entrance of the heterogeneous system into said hollow housing.

5. A unit according to claim 1, comprising: a control valve for flexible and smooth control of the amount of the discharged heterogeneous system; said valve communicating the inner space of said pipe for discharging the heterogeneous system with the vapourand gascontaining space of said autoclave.

6. A unit according to claim 2, comprising: a control valve for flexible and smooth control of the amount of the discharged heterogeneous system; said valve communicating the inner space of said pipe for discharging the heterogeneous system with the'vapourand gascontaining space of said autoclave.

7. A unit according to claim 3 comprising a control valve for flexible and smooth control of the amount of the discharged heterogeneous system; said valve communicating the inner space of said pipe for discharging the heterogeneous system with the vapourand gascontaining space of said autoclave.

8. A unit according to claim 1, wherein the direction of said helical groove on said inner surface of said hollow housing is opposite to the direction of rotation of said hollow housing, whereby an intensive stirring of heterogeneous system is ensured.

9. A unit according to claim 1, wherein the direction of said helical groove on said inner surface of said hollow housing coincides with the direction of rotation of said hollow housing, whereby an intensive discharge of the heterogeneous system is ensured.

10. A unit according to claim 1, wherein said filtering device has coarse-pore filtering elements fastened in rings between said fine-pore filtering elements are mounted along the height of said pipe for discharging the heterogeneous system, the inner rings of said coarse-pore filtering elements having a thread contacting the thread on the pipe for discharging the heterogeneous system.

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US3095280 *May 24, 1961Jun 25, 1963Pechiney Cie De Produits ChemiApparatus for the continuous digestion of bauxite
US3361537 *May 12, 1965Jan 2, 1968Du PontPolymer finishing apparatus
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US5647950 *Mar 9, 1995Jul 15, 1997Pall CorporationFilter assembly with a spin welded end cap
US5776342 *Mar 5, 1996Jul 7, 1998Pall CorporationFilter assembly
US5871645 *Aug 25, 1997Feb 16, 1999Pall CorporationFilter arrangement including a non-perforated housing and an axially pleated filter pack
US6103120 *Oct 23, 1995Aug 15, 2000Pall CorporationFluid processing apparatus
US6110368 *Jun 7, 1996Aug 29, 2000Pall CorporationFluid processing apparatus
US20100097879 *Jun 22, 2009Apr 22, 2010John KruegerApparatus and method for optimizing reaction time for curable material
DE3523060A1 *Jun 27, 1985Nov 13, 1986Littleford Bros IncKombinierte misch-, reaktions-, trocken- und filtervorrichtung
Classifications
U.S. Classification422/205, 422/226, 366/192, 210/413, 210/393, 422/199, 366/144, 210/408
International ClassificationC22B3/00, B01J19/18, C01F7/00, B01J3/04, C22B3/02, C01F7/06
Cooperative ClassificationC22B3/02, B01J2219/00132, B01J2219/00063, B01J19/18, C01F7/064, B01J2219/00155, B01J3/04
European ClassificationB01J19/18, B01J3/04, C22B3/02, C01F7/06D10