EP0061392A1 - Verfahren und Vorrichtung zur Elektrobehandlung von gemischten pulverigen Stoffen - Google Patents

Verfahren und Vorrichtung zur Elektrobehandlung von gemischten pulverigen Stoffen Download PDF

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Publication number
EP0061392A1
EP0061392A1 EP82400470A EP82400470A EP0061392A1 EP 0061392 A1 EP0061392 A1 EP 0061392A1 EP 82400470 A EP82400470 A EP 82400470A EP 82400470 A EP82400470 A EP 82400470A EP 0061392 A1 EP0061392 A1 EP 0061392A1
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EP
European Patent Office
Prior art keywords
compartment
anode
dissolution
electrolytic solution
compartments
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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EP82400470A
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English (en)
French (fr)
Inventor
Michel Ammou-Chokroum
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Centre National de la Recherche Scientifique CNRS
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Centre National de la Recherche Scientifique CNRS
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Publication of EP0061392A1 publication Critical patent/EP0061392A1/de
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    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25C—PROCESSES FOR THE ELECTROLYTIC PRODUCTION, RECOVERY OR REFINING OF METALS; APPARATUS THEREFOR
    • C25C1/00—Electrolytic production, recovery or refining of metals by electrolysis of solutions
    • C25C1/12—Electrolytic production, recovery or refining of metals by electrolysis of solutions of copper
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25C—PROCESSES FOR THE ELECTROLYTIC PRODUCTION, RECOVERY OR REFINING OF METALS; APPARATUS THEREFOR
    • C25C1/00—Electrolytic production, recovery or refining of metals by electrolysis of solutions

Definitions

  • the present invention relates to a method and a device for the electroprocessing of powders of composite materials comprising at least one conductive or semiconductor phase of electricity, such as the pulverulent materials obtained by grinding massive complex sulphide ores.
  • it relates to a method and a device for electrochemically and selectively dissolving one or more phases contained in ores, mineral-lurgical concentrates, selective or global, pyrometallurgical concentrates such as mattes, or else industrial or urban residues and by-products.
  • the subject of the present invention is precisely a process for the electroprocessing of powders of composite material comprising at least one electrically conductive or semi-conductive phase, for example of complex sulphide ores, which not only makes it possible to obtain the desired selectivity but also to ensure good recovery of the valuable elements in the reactor used for selective dissolution.
  • the electrolytic solution is advantageously a hydrochloric solution having a pH close to 1 and a chloride ion concentration of 3 to 4 M.
  • This chloride ion concentration is adjusted by adding chlorides chosen from the group comprising alkali metal chlorides, alkaline earth chlorides and mixtures thereof to the hydrochloric acid solution.
  • the anode is maintained at a potential less than +450 millivolts relative to the saturated calomel electrode, and one preferably operates with an anode potential maintained at a value of +425 millivolts relative to a calomel electrode.
  • the cell is electrically balanced by adding to the anolyte reducible ions constituted by ferric ions.
  • ferric ions can be obtained during a step of purification of the electrolytic solution before its recycling.
  • the electrolytic solution is treated to remove part of the iron which it contains by precipitating it in the form of oxides and / or hydroxides by means of oxygen under hot pressure, and it is recycled in the anode compartment the electrolytic solution thus treated which contains the rest of the iron in the form of ferric ions.
  • the subject of the present invention is also a device for electroprocessing powdered composite materials comprising at least one electrically conductive or semiconductive phase, which makes it possible to ensure, under good conditions, a selective dissolution of certain constituents of the powder, then then recover by electrodeposition the valuable items that have been dissolved.
  • the fact of using an electrolysis cell separated into at least two compartments by an ion-permeable diaphragm and of circulating in the electroplating compartment the electrolytic solution coming from the dissolution compartment thus makes it possible to carry out the selective dissolution of at least one phase of the powder and then be able to recover some of the elements thus dissolved by electrolytic deposition.
  • the electrical energy used is used as best as possible, since it serves not only to dissolve the elements of value, but also to recover them in metallic form by depositing on a cathode.
  • electrodissolution is carried out at a constant potential in order to remain in the range of potentials corresponding to the attack of the phase to dissolve. If one operated on the contrary with a substantially constant current intensity, the potential of the electrode would vary due, on the one hand, to the exhaustion of the spawn in electroactive species and, on the other hand, to the passivation of the latter resulting from their covering with protective solid reaction products; therefore, this potential could take on such a value that the electrolytic solution would be electrolyzed.
  • This parasitic reaction has several drawbacks: firstly, the energy efficiency of the operation decreases since the current is not only used for the solubilization of the solid phase to be recovered; - moreover, the electrolysis products of the electrolytic solution such as chlorine if one operates by oxidation in hydrochloric medium, .or oxygen if one operates in basic or sulfuric medium, constitute oxidizing agents which can be corrosive to the installation and dissolve certain products of the gangue, thereby altering the selectivity of dissolution sought and accentuating the soiling of the solutions.
  • the electrolysis cell which is separated into at least two compartments by an ion-permeable diaphragm, has a geometry favoring the kinetics of the operations of dissolution and deposition.
  • this cell is cylindrical and comprises two concentric compartments separated by the ion-permeable diaphragm; for dissolution by electrooxidation, the internal compartment constitutes the anode dissolution compartment and the external compartment constitutes the cathode electrodeposition compartment.
  • the anode compartment has a hemispherical bottom avoiding dead hydrodynamic zones.
  • the cell can also be produced in the form of a modular assembly comprising a plurality of anode compartments disposed inside a tank constituting the cathode compartment.
  • the means for circulating in the anode dissolution compartments a suspension of the powder of composite material in an electrolytic solution are designed so as to supply the anode compartments in series; the feed rate which determines the residence time of the powder in the various compartments is fixed in such a way that the powder is exhausted in the phase to be attacked at the outlet of the last anode compartment.
  • the cell is made of a material having good mechanical resistance and chemical inertia under the operating conditions of the electroprocessing device.
  • this cell can be made of a material reinforced with glass fibers.
  • the ion-permeable diaphragm which separates the different compartments of the electrolysis cell advantageously consists of a porous membrane, of small thickness, made for example of ceramic or plastic material such as polytetrafluoroethylene. Any porous material sufficiently inert under the operating conditions of the device can be used.
  • the diaphragm does not affect the selectivity of the diffusion of ions between the anode and cathode compartments; its function is only to prevent the powder of composite material present in one of the compartments from entering the neighboring compartment so as not to cause unfavorable reactions in the electrolytic solution circulating in this compartment, in particular when the latter. is the electroplating compartment so as not to disturb the deposit of metallic elements on the electrode of this compartment.
  • the diaphragm is constituted by a porous membrane of small thickness which is relatively fragile, this membrane is protected from the shock of the powder particles put into circulation in the dissolution compartment by appropriate means.
  • this porous diaphragm is arranged in the cell in such a way that it is not not too close to the electrode of the plating compartment in order to avoid crystallization of metallic elements in the diaphragm.
  • the electrode preferably has a three-dimensional structure in order to increase the frequency of contact with the powder particles circulating in this compartment. Indeed, to obtain the electrodissolution of the conductive or semicon- phases. ductrices of the powder, it is necessary that this powder can integrate into the electrical circuit of the cell: when a powder particle comes into contact with the electrode, it takes, if it is conductive, the potential of this electrode and if this potential corresponds to its electrodissolution domain, it dissolves for a very short time. Also, to favor this reaction, the electrode must have a shape such that it increases the frequency of contacts with the powder in suspension, this frequency of contacts being moreover favored by the turbulence of the solution circulating in the dissolution compartment.
  • This electrode is advantageously made of a material which conducts electricity well, for example graphite.
  • the three-dimensional electrode can be constituted by a grid deployed in the entire volume of the dissolution compartment or by a set of bars distributed in this compartment.
  • the means for agitating the powder particles present in the dissolving compartment can be constituted by an agitator of conventional type comprising a shaft provided with several blades distributed over the entire height of the compartment so as to ensure good turbulence of the powder in suspension, this tree being preferably arranged along the axis of the compartment.
  • the three-dimensional electrode consists of a hollow electrically conductive tube, arranged along the axis of the dissolution compartment, said tube supporting a plurality of perforated trays of conductive material, in contact with said hollow tube, said trays being spaced apart from each other in the vertical direction and occupying practically the entire cross section of the dissolution compartment.
  • the stirring means are constituted by pneumatic means.
  • the hollow tube is pierced with orifices at its upper part and it is associated with a second tube arranged coaxially inside the hollow tube, the second tube being in communication by its upper end with a source of compressed air and being open to . its lower end so as to constitute the means for agitating the suspension circulated in each dissolution compartment.
  • the device of the invention also comprises means for collecting the electrolytic solution leaving the dissolution compartment and circulating it in the electroplating compartment.
  • These means advantageously include a filtration device for se adorning the powder particles with the electrolytic solution leaving the dissolution compartment, and a pump for injecting the electrolytic solution thus separated into the electroplating compartment.
  • the device preferably comprises means for recycling into the dissolution compartment part of the electrolytic solution separated at the outlet of this compartment.
  • the composite material to be treated has a low content of valuable element, it is possible to obtain, in the dissolution compartment, a solution more concentrated in valuable elements, before introducing it into the electroplating compartment in order to 'improve the kinetics of electrolytic deposition of these elements.
  • the speed of electrodeposition is also increased by using as electrode in the electrodeposition compartments, a large surface electrode constituted for example by a porous percolating electrode.
  • this percolating porous electrode is preferably a fixed percolating porous electrode.
  • This can be constituted by a bed of grains conducting electricity in contact with each other and with a current supply.
  • This current supply can be embedded in the bed of conductive grains or be constituted by two grids arranged respectively at the base and at the top of the bed.
  • one can circulate the electrolytic solution through the bed and obtain an equipotential bed whose entire surface is working.
  • the operation of the cell is generally discontinuous.
  • the conductive grains of the percolating porous electrode are covered with a metallic deposit and the bed gradually becomes clogged.
  • the procedure is discontinuous, which can be annoying.
  • a fixed electrode, porous or otherwise which has the advantage of being equipotential.
  • the electrode is placed in the electroplating compartment so that its conductive elements are not in contact with the diaphragm to avoid that the deposit cannot take place in the pores of the diaphragm.
  • the deposit formed is a powdery deposit
  • the bed can be periodically pulsed.
  • the base of the cathode compartment is provided with a conductive coating brought to the same potential as the current supply, so as to avoid a possible chemical attack of the metal powder by the electrolytic solution.
  • the deposit formed in the electrodeposition compartment consists of a material which adheres to the electrode
  • this material can be recovered by electrochemical redissolution in a small volume of solution to obtain a concentrated solution directly.
  • This electrodeposited material can consist of an immediately usable metallic phase or else of a composite phase which must be subjected to an additional treatment in order to separate the elements from it.
  • the composite deposit can be chemically or electrochemically dissolved in a small volume of solution to obtain a concentrated solution and thus be able to be treated by expensive but effective separation techniques such as solvent extraction, precipitation by pressurized hydrogen, etc.
  • the device of the invention comprises an electrolysis cell 1 separated into two concentric compartments, by a diaphragm 3 permeable to ions, the internal compartment 5 constituting the anode dissolution compartment and the external compartment 6 constituting the cathodic electroplating compartment.
  • An anode 7 and an agitator 8 are arranged inside the anode compartment 5; the anode 7 is constituted by a set of graphite bars which are connected to the positive pole of a potentiostatic device 9.
  • the cathode 11 disposed in the electroplating compartment 6, is constituted by graphite bars 11 which are connected to the negative pole of the device 9.
  • the suspension of powder to be treated or pulp can be introduced into the anode compartment via line 13, this pulp is prepared in device 15 which is supplied, on the one hand, with soli. treat by the discharge hopper 17 and, on the other hand, in electrolytic solution via line 19.
  • the pulp is evacuated from the anode compartment by an overflow system 21, then is filtered through a porous filter 23, the solid particles being evacuated from the installation at 25 and the electrolytic solution being collected in a tank 27 then put in circulation via a pump 29 in the cathode compartment 6 of the electrolysis cell.
  • the electrolytic solution is then evacuated from the cathode compartment 6 via line 31, then recycled by the pump 33 into the anode compartment 5 by means of the device 15 for preparing the pulp.
  • the device further comprises a system for maintaining the anode 7 at a constant potential with respect to the reference electrode 35.
  • FIG 2 there is shown an alternative embodiment of the cell of the device shown in Figure 1.
  • a hollow tube 51 is used as current supply, which supports a plurality of perforated plates 53 made of electrically conductive material, which occupy practically the entire cross section of the anode compartment.
  • These trays are spaced from each other vertically cal and they constitute with the tube 51 an anode having a three-dimensional structure which makes it possible to obtain a large electrode surface area per cell volume.
  • the tube 51 constitutes one of the elements of a system of the "Air Lift" type, which ensures the mixing of the powder particles in suspension in the electrolytic solution which circulates in the anode compartment.
  • the tube 51 is associated with a second tube 55 arranged coaxially inside the tube 51, this tube 55 is in communication at its upper end with a source of compressed air and it is open at its lower end 55a which opens at a level slightly higher than the lower end of the tube 51.
  • the tube 51 is pierced with orifices 5la in its upper part so that during the injection of air into the tube 55, the mixture pulp-air which rises inside the tube 51 can be discharged through these orifices and ensure the agitation of the suspension which circulates in the anode compartment in which the particles strike the plates of the electrode before being at again sucked in by the "Air Lift".
  • a pipe 56 which opens into the upper part of the tube 51.
  • the suspension of ore powder is evacuated from the anode compartment 5 by the outlet pipe provided with a valve 57 for adjusting the flow, and it is directed to a filtration system as in the case of FIG. 1.
  • the device of the invention can be used to treat a pyrite (Py) -chalcopyrite (Cp) mixture in an electrolytic solution of hydrochloric acid having a pH substantially equal to 1 and a concentration of chloride ions of 3M, in operating at 50 ° C.
  • a pyrite (Py) -chalcopyrite (Cp) mixture in an electrolytic solution of hydrochloric acid having a pH substantially equal to 1 and a concentration of chloride ions of 3M, in operating at 50 ° C.
  • the potential of the anode was fixed at different values ranging from +400 to +500 millivolts relative to the reference electrode to the calomel.
  • the evolution of the selectivity in dissolving the chalcopyrite as measured by the solubilized copper / iron ratio is followed (there is selectivity when Cu / Fe is equal to 1), as a function of the progress of the reaction measured. by the quantity of electricity Q having passed through the circuit.
  • Figure 3 illustrates the results obtained for a potential of +400 and +425 millivolts (curve 1), for a potential of +450 millivolts (curve 2), for a potential of +475 millivolts (curve 3) and 'for a potential of +500 millivolts (cour - be 4).
  • a global pyritic concentrate containing copper, lead and zinc is treated.
  • the operation is carried out at a temperature ranging from 50 ° C. to 80 ° C. and the overall concentrate is introduced into the anode compartment in the form of pulp in a hydrochloric acid solution having a pH close to 1 and a concentration of chloride ions of about 4M, which was adjusted by adding sodium chloride and calcium chloride.
  • the potential of the anode is fixed at +425 millivolts / ECS, potential at which the pyrite is not attacked.
  • x corresponds to the fraction of H 2 S collected by the anode, and that it is between 0 and 1.
  • the quantity of sulfur produced is (xA + xB + C + 2D) S 0 and the quantity of current used at the anode corresponds to 2 (xA + xB + C + 2D) e.
  • the electrolytic solution is evacuated by the overflow system and then filtered; after filtration, it is introduced. in the cathode compartment 6 where the following reactions schematically occur:
  • the quantity of. current used is 2 (A + B + C + D) e - .
  • Fe 3+ ions which can be reduced under these conditions are introduced into the anode compartment: (D + (1-x) A + (1-x) B) Fe 3+ ions must be reduced in Fe2 + on the anode to balance the anode and cathode currents by decreasing the overall anode current. Furthermore, the introduction of Fe 3+ ions makes it possible to oxidize the fraction of H 2 S which is not electrooxidized.
  • ferric ions can be carried out using Fe 3+ ions recovered from the ferric solution which leaves the solution purification step.
  • the solution from the cathode compartment contains ferrous ions which come from the solubilization of the iron from chalcopyrite and sphalerite present in pyrite sulphide ores.
  • part of it must be eliminated by subjecting the electrolytic solution leaving the compartment to treatment with pressurized oxygen.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Electrolytic Production Of Metals (AREA)
  • Electrolytic Production Of Non-Metals, Compounds, Apparatuses Therefor (AREA)
EP82400470A 1981-03-19 1982-03-15 Verfahren und Vorrichtung zur Elektrobehandlung von gemischten pulverigen Stoffen Withdrawn EP0061392A1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR8105512 1981-03-19
FR8105512A FR2502187B1 (fr) 1981-03-19 1981-03-19 Procede et dispositif pour l'electrotraitement de materiaux composites pulverulents

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EP0061392A1 true EP0061392A1 (de) 1982-09-29

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Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0219473A1 (de) * 1985-09-05 1987-04-22 Boliden Mineral AB Verfahren zur selektiven Gewinnung von Blei aus komplexen sulfidischen Nicht-Eisen-Metallkonzentraten
WO1987006274A1 (en) * 1986-04-16 1987-10-22 Imperial College Of Science & Technology Metal recovery
EP0094308B1 (de) * 1982-05-06 1988-07-27 SOCIETE MINIERE ET METALLURGIQUE DE PENARROYA Société anonyme dite: Verfahren und Vorrichtung zur elektrolytischen Herstellung von Metallen, insbesondere Blei
EP0654547A1 (de) * 1993-11-22 1995-05-24 Sociedad de Desarrollo Minero Limitada "SODEMI LTDA" Electrochemisches Raffinieren von Metallen
CN107893243A (zh) * 2017-12-20 2018-04-10 中科京投环境科技江苏有限公司 一种旋流矿浆电解脱除重金属的装置及脱除方法
CN112064062A (zh) * 2020-11-10 2020-12-11 矿冶科技集团有限公司 废铅膏免预脱硫联合电解制备粗铅的方法

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3736238A (en) * 1972-04-21 1973-05-29 Cyprus Metallurg Process Process for the recovery of metals from sulfide ores through electrolytic dissociation of the sulfides
GB2009789A (en) * 1977-12-06 1979-06-20 Broken Hill Pty Co Ltd Simultaneous electrodissolution and electrowinning of metals from sulphide minerals
US4197181A (en) * 1978-10-23 1980-04-08 Kennecott Copper Corporation Stationary particulate bed dual electrode

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3736238A (en) * 1972-04-21 1973-05-29 Cyprus Metallurg Process Process for the recovery of metals from sulfide ores through electrolytic dissociation of the sulfides
GB2009789A (en) * 1977-12-06 1979-06-20 Broken Hill Pty Co Ltd Simultaneous electrodissolution and electrowinning of metals from sulphide minerals
US4197181A (en) * 1978-10-23 1980-04-08 Kennecott Copper Corporation Stationary particulate bed dual electrode

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0094308B1 (de) * 1982-05-06 1988-07-27 SOCIETE MINIERE ET METALLURGIQUE DE PENARROYA Société anonyme dite: Verfahren und Vorrichtung zur elektrolytischen Herstellung von Metallen, insbesondere Blei
EP0219473A1 (de) * 1985-09-05 1987-04-22 Boliden Mineral AB Verfahren zur selektiven Gewinnung von Blei aus komplexen sulfidischen Nicht-Eisen-Metallkonzentraten
WO1987006274A1 (en) * 1986-04-16 1987-10-22 Imperial College Of Science & Technology Metal recovery
EP0654547A1 (de) * 1993-11-22 1995-05-24 Sociedad de Desarrollo Minero Limitada "SODEMI LTDA" Electrochemisches Raffinieren von Metallen
CN107893243A (zh) * 2017-12-20 2018-04-10 中科京投环境科技江苏有限公司 一种旋流矿浆电解脱除重金属的装置及脱除方法
CN107893243B (zh) * 2017-12-20 2024-05-07 中科京投环境科技江苏有限公司 一种旋流矿浆电解脱除重金属的装置及脱除方法
CN112064062A (zh) * 2020-11-10 2020-12-11 矿冶科技集团有限公司 废铅膏免预脱硫联合电解制备粗铅的方法
CN112064062B (zh) * 2020-11-10 2021-02-12 矿冶科技集团有限公司 废铅膏免预脱硫联合电解制备粗铅的方法

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Publication number Publication date
FR2502187A1 (fr) 1982-09-24
FR2502187B1 (fr) 1985-09-20

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