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
  • C22B7/00—Working up raw materials other than ores, e.g. scrap, to produce non-ferrous metals and compounds thereof; Methods of a general interest or applied to the winning of more than two metals
• • 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
  • C22B19/00—Obtaining zinc or zinc oxide
  • C22B19/04—Obtaining zinc by distilling
• • 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
  • C22B1/00—Preliminary treatment of ores or scrap
  • C22B1/14—Agglomerating; Briquetting; Binding; Granulating
• • 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
  • C22B19/00—Obtaining zinc or zinc oxide
  • C22B19/30—Obtaining zinc or zinc oxide from metallic residues or scraps
• • 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
  • C22B5/00—General methods of reducing to metals
  • C22B5/02—Dry methods smelting of sulfides or formation of mattes
  • C22B5/10—Dry methods smelting of sulfides or formation of mattes by solid carbonaceous reducing agents
• • 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
  • C22B5/00—General methods of reducing to metals
  • C22B5/02—Dry methods smelting of sulfides or formation of mattes
  • C22B5/16—Dry methods smelting of sulfides or formation of mattes with volatilisation or condensation of the metal being produced
• • 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
  • C22B7/00—Working up raw materials other than ores, e.g. scrap, to produce non-ferrous metals and compounds thereof; Methods of a general interest or applied to the winning of more than two metals
  • C22B7/001—Dry processes
• • 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
  • C22B7/00—Working up raw materials other than ores, e.g. scrap, to produce non-ferrous metals and compounds thereof; Methods of a general interest or applied to the winning of more than two metals
  • C22B7/001—Dry processes
  • C22B7/002—Dry processes by treating with halogens, sulfur or compounds thereof; by carburising, by treating with hydrogen (hydriding)
• • 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

• This invention relates to the separation of metals in Fe-bearing zinc leaching residues, in particular neutral and weak acid leach residues.
• Blende which is an impure ZnS ore, is the main starting material for the production of Zn.
• the typical industrial practice encompasses an oxidative roasting step, producing ZnO together with sulphates or oxides of the impurities.
• the ZnO in roasted blende is brought into solution by leaching in neutral conditions or in weak acidic conditions, thereby producing Zn-depleted residues, respectively referred to as neutral leach residue and as weak acid leach residue in this description.
• These residues typically contain from 2 to 10 wt. % S, up to 30 wt % Zn, 35 wt % Fe, 7 wt % Pb and 7 wt % SiO 2 .
• the leach residues therefore contain, besides lead sulphate, calcium sulphate and other impurities, a sizeable fraction of Zn in the form of ferrite.
• the recovery of the Zn from ferrite requires a specific hydro-metallurgical residue treatment using high acid concentrations of 50 to 200 g/l H 2 SO 4 .
• a disadvantage of this acidic treatment is that besides Zn, almost all the Fe and also other impurities such as As, Cu, Cd, Ni, Co, Tl, Sb are dissolved.
• Waelz kilns which produce a slag and a Zn and Pb containing fume.
• Waelz kilns Such a process is described in ‘Steelworks residues and the Waelz kiln treatment of electric arc furnace dust’, G. Strohmeier and J. Bonestell, Iron and Steel Engineer vol. 73, N o 4, pp. 87-90.
• zinc enters in the form of ferrites and sulphate, and is vaporized after being reduced by CO generated by burning cokes.
• the reaction zone of the kiln where iron is reduced to metal, the problem of overheating occurs frequently.
• the charge in the kiln melts and accretions are formed, mainly due to the formation of the eutectic 2FeO.SiO 2 —FeO, which has a melting point of approximately 1180° C.
• the dissolution of FeO further lowers the melting point and through combination with zinc sulphide, reduced from zinc sulphate in the earlier stages, solid crusts are formed.
• the furnace rotation is further hampered by the formation of large balls consisting of carbonized iron, which are formed as a molten metallic phase at approx. 1150° C.
• WO2005-005674 a process for the separation and recovery of non-ferrous metals from zinc-bearing residues was disclosed.
• the process comprises the steps of subjecting the residue to a direct reduction step, extracting Zn- and Pb-bearing fumes, and subjecting the resulting metallic Fe-bearing phase to an oxidising smelting step.
• the direct reduction is performed in a multiple hearth furnace operating at 1100° C. in the reduction zone.
• One disadvantage of the use of such a reduction furnace is that the reduction kinetics are limited by the temperature. Temperatures above 1100° C. can however not be reached in a multiple hearth furnace.
• JP2004-107748 describes a process for the treatment of zinc leaching residues in a rotary hearth furnace, at a reduction temperature up to 1250° C.
• the burner air ratio is set within a limited range.
• the aim of the present invention is to provide a process for the separation of the metals contained in Fe-bearing zinc leaching residues, which does not have the disadvantages described above. This process comprises the steps of:
• the Zn leaching residue should preferably be dried to a moisture content of less than 12 wt. % H 2 O, or even to less than 5 wt. % H 2 O, before preparing the agglomerates.
• a carbon content in the agglomerates of at least 15 wt. % is preferred, as is a CaO equivalent of at least 10 wt. %, or even at least 15 wt. %.
• the strength of the pellets should preferably be at least 5 kg, or even 10 kg. This way dust carry over is avoided and the fusion of the charge is better prevented at the high process temperatures.
• the fuming should advantageously be performed at a temperature of at least 1300° C., in a carbon monoxide containing atmosphere
• the process is ideally suited for processing neutral or weak acid Zn leach residues.
• the invented process can be performed in a in a rotary hearth furnace; it can optionally be followed by a process whereby the reduced Fe-bearing phase is melted and oxidised.
• the high S content of the feed allows for a relatively high operating temperature without producing molten phases. There is thus no danger for the formation of accretions at the discharge port of the furnace.
• High temperatures guarantee fast reduction and fuming kinetics, which permit the use of a compact technology such as a static bed furnace. This type of furnace furthermore preserves the integrity of the agglomerates, avoiding to a large extent the production of dust and limiting the ensuing pollution of the fumes.
• the following example illustrates the separation of different non-ferrous metals contained in a roasted and subsequently leached blende.
• WAL Weak Acid Leaching
• the fuming step was carried out in an induction furnace to simulate the process occurring in a rotating hearth furnace.
• An Indutherm MU-3000 furnace with a maximum power of 15 kW and a frequency of 2000 Hz was used.
• the internal furnace diameter was 180 mm, and the graphite crucible carrying the briquettes had an internal diameter of 140 mm.
• Approximately 400 g briquettes was placed on the bottom of the clean graphite crucible, in such a way that the crucible surface is covered with a single layer of material.
• the crucible was then placed in the induction furnace, and a monitoring thermocouple was mounted between the briquettes without touching the crucible bottom.
• the crucible was covered by a refractory plate.
• the fumed metals were post combusted above the crucible and captured in a filter under the form of flue dust.
• the reactor and the material were heated at to 1300° C., as measured with a Pt/PtRh10 thermocouple mounted between the briquettes.
• This example illustrates the crucial role of S the briquettes, as it avoids the softening and melting of the material during the roasting process without loss in the selectivity.

Landscapes

• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Metallurgy (AREA)
• Manufacturing & Machinery (AREA)
• Materials Engineering (AREA)
• Mechanical Engineering (AREA)
• Organic Chemistry (AREA)
• Geology (AREA)
• General Life Sciences & Earth Sciences (AREA)
• Environmental & Geological Engineering (AREA)
• Life Sciences & Earth Sciences (AREA)
• Geochemistry & Mineralogy (AREA)
• Manufacture And Refinement Of Metals (AREA)
• Manufacture Of Iron (AREA)
• Processing Of Solid Wastes (AREA)

Priority Applications (1)

Applications Claiming Priority (5)

Publications (1)

Family

ID=35240857

Family Applications (1)

Country Status (14)

Families Citing this family (9)

Citations (6)

Family Cites Families (3)

• 2006
  • 2006-05-11 WO PCT/EP2006/004412 patent/WO2006133777A1/en active Application Filing
  • 2006-05-11 AU AU2006257458A patent/AU2006257458A1/en not_active Abandoned
  • 2006-05-11 MX MX2007015812A patent/MX2007015812A/es unknown
  • 2006-05-11 KR KR20077028617A patent/KR20080022545A/ko not_active Application Discontinuation
  • 2006-05-11 ZA ZA200710377A patent/ZA200710377B/xx unknown
  • 2006-05-11 BR BRPI0612150A patent/BRPI0612150A2/pt not_active IP Right Cessation
  • 2006-05-11 CA CA002611925A patent/CA2611925A1/en not_active Abandoned
  • 2006-05-11 EP EP06753557A patent/EP1893779A1/en not_active Withdrawn
  • 2006-05-11 JP JP2008515071A patent/JP2008545888A/ja not_active Withdrawn
  • 2006-05-11 CN CNA2006800209006A patent/CN101341265A/zh active Pending
  • 2006-05-11 US US11/917,278 patent/US20080196551A1/en not_active Abandoned
  • 2006-05-11 EA EA200800030A patent/EA013690B1/ru not_active IP Right Cessation
  • 2006-06-08 PE PE2006000634A patent/PE20070088A1/es not_active Application Discontinuation
• 2008
  • 2008-01-03 NO NO20080042A patent/NO20080042L/no not_active Application Discontinuation

Patent Citations (6)

Also Published As

Similar Documents

Legal Events