Classifications

• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
  • C22B3/00—Extraction of metal compounds from ores or concentrates by wet processes
  • C22B3/02—Apparatus therefor
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D11/00—Solvent extraction
  • B01D11/04—Solvent extraction of solutions which are liquid
  • B01D11/0446—Juxtaposition of mixers-settlers
  • B01D11/0457—Juxtaposition of mixers-settlers comprising rotating mechanisms, e.g. mixers, mixing pumps
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D17/00—Separation of liquids, not provided for elsewhere, e.g. by thermal diffusion
  • B01D17/02—Separation of non-miscible liquids
  • B01D17/0208—Separation of non-miscible liquids by sedimentation
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D17/00—Separation of liquids, not provided for elsewhere, e.g. by thermal diffusion
  • B01D17/02—Separation of non-miscible liquids
  • B01D17/0208—Separation of non-miscible liquids by sedimentation
  • B01D17/0211—Separation of non-miscible liquids by sedimentation with baffles
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D17/00—Separation of liquids, not provided for elsewhere, e.g. by thermal diffusion
  • B01D17/02—Separation of non-miscible liquids
  • B01D17/0208—Separation of non-miscible liquids by sedimentation
  • B01D17/0214—Separation of non-miscible liquids by sedimentation with removal of one of the phases
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D17/00—Separation of liquids, not provided for elsewhere, e.g. by thermal diffusion
  • B01D17/02—Separation of non-miscible liquids
  • B01D17/04—Breaking emulsions
  • B01D17/045—Breaking emulsions with coalescers
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
  • C22B3/00—Extraction of metal compounds from ores or concentrates by wet processes
  • C22B3/20—Treatment or purification of solutions, e.g. obtained by leaching
  • C22B3/26—Treatment or purification of solutions, e.g. obtained by leaching by liquid-liquid extraction using organic compounds
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
  • Y02P10/00—Technologies related to metal processing
  • Y02P10/20—Recycling

Definitions

• the present invention relates to a method for recirculating the heavier solution in liquid-liquid extraction in between the solution separation part and mixing unit in a process where two unmixed solutions are first mixed and then the solutions are separated.
• the invention also relates to a collecting channel whereby the circulation of the heavier solution is realized.
• the aqueous solution is gathered evenly also from a wide separation part, so that it does not disturb the proceeding of the extraction solutions flowing in the separation part.
• Another object of the invention is, by means of controlled circulation, to intensify the bottom flow in the longitudinal direction of the separation part and thus even out the vertical flows in this space.
• one of the employed separation methods is liquid-liquid extraction, where the heavier solution generally is an aqueous solution, and the lighter solution is an organic solution, such as kerosene, to which some suitable extraction chemical is dissolved.
• the heavier solution generally is an aqueous solution
• the lighter solution is an organic solution, such as kerosene, to which some suitable extraction chemical is dissolved.
• flow control is particularly important, even to an extent where it may prove to be a restricting factor as for the size of the plant in question.
• the extraction solution flow can be 1 ,000 - 2,000 m /h, when the external basic solution feed is only of the order 10 - 50 m 3 /h, i.e. in this case the internal recirculation need of the aqueous solution is nearly equal to the feed.
• the internal solution circulation is obtained from chutes located at the discharge end of the separation part, to which chutes the purified solution is gathered as overflow.
• the circulation volume of the aqueous solution is increased, water runs up in the chute, and the desired circulation rate is obtained only gradually, as the external solution supply brings in more aqueous solution. This is due to the fact that an increase in the water supply increases the share of aqueous solutions in the mixing unit, and therefore respectively displaces organic solution.
• aqueous solution conducted into the mixing unit does not re-enter the circulation of the separation part, but the supply of aqueous solution is stopped for a long time. This leads to serious trouble in a process situation where it would be important to wash the extraction solution of difficult impurities; in copper extraction, these are, among others, chlorides, manganese and iron.
• the above described drawback is eliminated according to the present invention by arranging in the separation part, i.e. in the settler, at least one collecting channel, which extends over the whole width of the separation part.
• this collecting channel there is conducted the major part of the required heavier solution, i.e. of the aqueous solution, directly from the separation part proper, and only a small part from the discharge end, and the aqueous solution to be recirculated is conducted into the mixing unit.
• the aqueous solution quantity needed in the mixing unit can be supplied irrespective of external feed or the scarcity of aqueous solution in the discharge end of the separation part.
• the collecting channel is advantageously located in the aqueous solution space of the separation part, i.e.
• the top surface of the collecting channel can be located at the bottom surface of the lighter solution, i.e. of the organic solution, or at the bottom of the separation part.
• the aqueous solution is absorbed into the channel by means of suction pipes attached thereto.
• figure 1 is a top-view illustration of the mixing and separation parts belonging to the extraction step
• figure 2 shows a cross-section of the settler at the channel structure
• figure 3 is a partial cross-section of the channel according to the invention
• figure 4 is a side-view illustration of the settler.
• the mixing unit 1 of the extraction step comprises a pump unit 2 and two mixers 3 and 4, and from the last mixer in the flowing direction there is discharged a controllably mixed two-phase dispersion through an aperture 5 into the separation part, i.e. into the settler 6.
• the front end of the settler is advantageously provided with several picket fences 7 and 8, and at the final end 9 of the settler there is installed both an organic phase overflow chute 10, provided with recirculation pipes (not illustrated in the drawing) and a water end 11 of the aqueous phase, provided with recirculation pipes 12.
• a collecting channel 13 extending over the whole width of the settler, which collecting channel is connected to the aqueous solution circulation pipe 12.
• the collecting channel is located in between the last picket fence 8 and the organic phase collecting chute 10.
• the collecting channel 13 is encased in a channel casing 14.
• the number of the recirculation pipes 12 can be one or several; in the latter case, the construction of oversized pipes can be avoided.
• the collecting channel 13 is mainly formed of a tubular element placed inside the aqueous solution layer and provided with suction pipes 15 that are directed downwards in an inclined fashion and are open at both ends.
• the collecting channel can be supported inside the aqueous solution layer, as was described above, it can also be embedded in the settler bottom structure, in which case the pipes absorbing the aqueous solution are directed upwards in an inclined fashion.
• the suction pipes are always oriented from the collecting channel 13 towards the aqueous solution 16 to be collected.
• the channel is designed so that it expands gradually prior to each suction pipe 15, when proceeding towards the settler edge on the side of the circulation pipe 12, as is seen in figure 1.
• the flowing direction of the solution proceeding in the channel 13 is the one indicated by an arrow in figure 1 , i.e. transversal with respect to the flowing direction of the settler solutions.
• the suction pipe 15 enters the channel 13 for a length that is 0.1 - 0.4 times the channel height and advantageously 0.2 - 0.3 times the channel height.
• the channel 13 When the channel 13 is observed in the flowing direction thereof (towards the circulation pipe 12), the channel expands gradually so that each expanding spot is located in the channel somewhat before the next suction pipe 15.
• the channel flow is made to strongly sweep over the input spots, at the same time as there is made room for incoming solution quantities.
• This structure also helps the input suctions to be distributed evenly between the separate suction pipes.
• a prerequisite for the aqueous solution circulation according to the invention as well as for the advantages offered thereby is an even suction extending over the width of the separation part.
• the structure of the collecting channel 13 is essential, as was already maintained.
• the number of single suction pipes in the collecting channel can be varied depending on the width of the separation part, but advantageously the number of suction pipes is at least three, generally 3 - 7.
• the detailed structure of the channel casing 14 may also vary, but if the channel 13 together with the casing 14 are installed in a aqueous solution space 16 underneath the layer of the organic phase 17, it is advantageous to design the channel casing 14 so that its sides 18 and 19 parallel to the settler flow are formed to be curved, advantageously semispherical, as is illustrated in figure 4.
• the width/height ratio of the casing is advantageously between 2 and 8, and the higher the internal recirculation need of the aqueous solution, the higher the ratio.
• the essentially semispherical sides are advantageous both from the point of view of strength and flow.
• the curved shape of the surface arranged particularly against the settler flow directs the organic entrainment fog upwards and thus helps the small drops mechanically rise to their own solution phase. As for the curvature of the discharge end, it prevents the formation of excessive discharge turbulences, which could cause excessive turbulence in the vicinity of the boundary surface and thus lead to a new formation of drops in the organic phase.
• the arrangement according to the invention offers a possibility to flexibly and with swift changes circulate all the various aqueous solution quantities that are required in the process, because the whole water quantity contained in the large separation part is available. It is particularly advantageous to use the method and apparatus according to the invention in connection with a separation part that is deeper than usual, in which case the separation part is designed so that when conventionally the ratio of the layer thicknesses of the organic and aqueous solutions at the final end of the separation part is of the order 1 :1.5, it is at least 1 :2.0, even 1 :4 when a deeper separation part is employed. Said structure smoothes out vertical flows in the separation part, i.e. the bottom flows in the separation part are intensified.
• FIG 3 it can also be seen how a channel, after a possible bend, is connected to the circulation pipe 12, which leads to the pump unit 2 of said extraction step. While the pump unit sucks aqueous solution from the collecting channel 13 of the separation part, and not from the discharge chute 11 leading to the next process step, there is also achieved the remarkable advantage that the return flow from the pump in connection with driving down or during a power failure does not conduct the organic solution back along a path that leads to the next process step. This is particularly important as for the copper re-extraction step, where said route leads to electrowinning. Because an organic solution in the electrolytic electrical precipitation of copper could cause serious trouble in the process, the circulation practice according to the present invention ensures an undisturbed copper production as regards this aspect.

Landscapes

• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Engineering & Computer Science (AREA)
• Thermal Sciences (AREA)
• Physics & Mathematics (AREA)
• Geology (AREA)
• Geochemistry & Mineralogy (AREA)
• Life Sciences & Earth Sciences (AREA)
• Materials Engineering (AREA)
• Mechanical Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Manufacturing & Machinery (AREA)
• General Life Sciences & Earth Sciences (AREA)
• Environmental & Geological Engineering (AREA)
• Extraction Or Liquid Replacement (AREA)
• Sampling And Sample Adjustment (AREA)
• Manufacture And Refinement Of Metals (AREA)
• Jet Pumps And Other Pumps (AREA)

Priority Applications (4)

Applications Claiming Priority (2)

Publications (1)

Family

ID=8545934

Family Applications (1)

Country Status (12)

Cited By (7)

Families Citing this family (13)

Citations (2)

Family Cites Families (8)

• 1996
  • 1996-04-30 FI FI961831A patent/FI100949B/fi not_active IP Right Cessation
• 1997
  • 1997-04-23 ZA ZA9703480A patent/ZA973480B/xx unknown
  • 1997-04-29 AR ARP970101756A patent/AR006894A1/es unknown
  • 1997-04-29 CN CN97194294A patent/CN1090515C/zh not_active Expired - Fee Related
  • 1997-04-29 CA CA002253281A patent/CA2253281C/en not_active Expired - Fee Related
  • 1997-04-29 BR BR9709201-0A patent/BR9709201A/pt not_active IP Right Cessation
  • 1997-04-29 RU RU98121405/12A patent/RU2181613C2/ru not_active IP Right Cessation
  • 1997-04-29 WO PCT/FI1997/000252 patent/WO1997040900A1/en active Application Filing
  • 1997-04-29 PE PE1997000321A patent/PE57498A1/es not_active Application Discontinuation
  • 1997-04-29 US US09/171,597 patent/US6083400A/en not_active Expired - Lifetime
  • 1997-04-29 AU AU23903/97A patent/AU726030B2/en not_active Ceased
  • 1997-04-29 IN IN270BO1997 patent/IN188544B/en unknown

Patent Citations (2)

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