Classifications

• • A—HUMAN NECESSITIES
  • A62—LIFE-SAVING; FIRE-FIGHTING
  • A62D—CHEMICAL MEANS FOR EXTINGUISHING FIRES OR FOR COMBATING OR PROTECTING AGAINST HARMFUL CHEMICAL AGENTS; CHEMICAL MATERIALS FOR USE IN BREATHING APPARATUS
  • A62D3/00—Processes for making harmful chemical substances harmless or less harmful, by effecting a chemical change in the substances
  • A62D3/40—Processes for making harmful chemical substances harmless or less harmful, by effecting a chemical change in the substances by heating to effect chemical change, e.g. pyrolysis
• • 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
  • C22B43/00—Obtaining mercury
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23G—CREMATION FURNACES; CONSUMING WASTE PRODUCTS BY COMBUSTION
  • F23G7/00—Incinerators or other apparatus for consuming industrial waste, e.g. chemicals
  • F23G7/003—Incinerators or other apparatus for consuming industrial waste, e.g. chemicals for used articles
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M6/00—Primary cells; Manufacture thereof
  • H01M6/52—Reclaiming serviceable parts of waste cells or batteries, e.g. recycling
• • A—HUMAN NECESSITIES
  • A62—LIFE-SAVING; FIRE-FIGHTING
  • A62D—CHEMICAL MEANS FOR EXTINGUISHING FIRES OR FOR COMBATING OR PROTECTING AGAINST HARMFUL CHEMICAL AGENTS; CHEMICAL MATERIALS FOR USE IN BREATHING APPARATUS
  • A62D2101/00—Harmful chemical substances made harmless, or less harmful, by effecting chemical change
  • A62D2101/20—Organic substances
  • A62D2101/24—Organic substances containing heavy metals
• • A—HUMAN NECESSITIES
  • A62—LIFE-SAVING; FIRE-FIGHTING
  • A62D—CHEMICAL MEANS FOR EXTINGUISHING FIRES OR FOR COMBATING OR PROTECTING AGAINST HARMFUL CHEMICAL AGENTS; CHEMICAL MATERIALS FOR USE IN BREATHING APPARATUS
  • A62D2101/00—Harmful chemical substances made harmless, or less harmful, by effecting chemical change
  • A62D2101/40—Inorganic substances
  • A62D2101/43—Inorganic substances containing heavy metals, in the bonded or free state
• • A—HUMAN NECESSITIES
  • A62—LIFE-SAVING; FIRE-FIGHTING
  • A62D—CHEMICAL MEANS FOR EXTINGUISHING FIRES OR FOR COMBATING OR PROTECTING AGAINST HARMFUL CHEMICAL AGENTS; CHEMICAL MATERIALS FOR USE IN BREATHING APPARATUS
  • A62D2203/00—Aspects of processes for making harmful chemical substances harmless, or less harmful, by effecting chemical change in the substances
  • A62D2203/04—Combined processes involving two or more non-distinct steps covered by groups A62D3/10 - A62D3/40
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23G—CREMATION FURNACES; CONSUMING WASTE PRODUCTS BY COMBUSTION
  • F23G2201/00—Pretreatment
  • F23G2201/30—Pyrolysing
  • F23G2201/304—Burning pyrosolids
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23G—CREMATION FURNACES; CONSUMING WASTE PRODUCTS BY COMBUSTION
  • F23G2209/00—Specific waste
  • F23G2209/30—Solid combustion residues, e.g. bottom or flyash
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23G—CREMATION FURNACES; CONSUMING WASTE PRODUCTS BY COMBUSTION
  • F23G2900/00—Special features of, or arrangements for incinerators
  • F23G2900/70—Incinerating particular products or waste
  • F23G2900/7007—Incinerating or pyrolysing used batteries
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23L—SUPPLYING AIR OR NON-COMBUSTIBLE LIQUIDS OR GASES TO COMBUSTION APPARATUS IN GENERAL ; VALVES OR DAMPERS SPECIALLY ADAPTED FOR CONTROLLING AIR SUPPLY OR DRAUGHT IN COMBUSTION APPARATUS; INDUCING DRAUGHT IN COMBUSTION APPARATUS; TOPS FOR CHIMNEYS OR VENTILATING SHAFTS; TERMINALS FOR FLUES
  • F23L2900/00—Special arrangements for supplying or treating air or oxidant for combustion; Injecting inert gas, water or steam into the combustion chamber
  • F23L2900/07002—Injecting inert gas, other than steam or evaporated water, into the combustion chambers
• • 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
• • 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
  • Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
  • Y02W30/00—Technologies for solid waste management
  • Y02W30/50—Reuse, recycling or recovery technologies
  • Y02W30/84—Recycling of batteries or fuel cells

Definitions

• the present invention relates to a method for decontamination by means of pyrolysis of solids, powders and sludge contaminated by mercury.
• the present invention is used in particular in a method for recycling a mixture of disused device batteries of any chemical composition, in which the unsorted mixture is pyrolyzed in a first step and the pyrolysis slag is subsequently processed further.
• EP-0-274 059 discloses a process for recycling such a mixture (as well as populated printed circuit boards and electronic components) in which, according to the patent, pyrolysis of the unsorted mixture at a temperature between 450 ° C. and 650 ° C, then an electrolysis of the pyrolysis slag is carried out in a solution of borofluorohydric acid and its salts, and the electrolysis products are then separated and the products obtained on the electrodes are removed.
• plastic, starch, colors and other organic components are carbonized without complex decomposition products (in particular PCBs, dioxins) already being produced.
• the pyrolysis is preferably carried out in an inert or reducing atmosphere in order to avoid the risk of explosion and to prevent metal oxidation.
• the volatile components are drawn off from the furnace or distilled off.
• the pyrolysis gas and steam products such as water, carbon dioxide, carbon onoxide, hydrochloric acid, ammonium chloride and in particular mercury, are passed over coolers, scrubbing columns and gas filter systems according to known technology.
• the mercury is condensed and recovered. It has been shown that at the usual mercury concentrations in the starting material, from a few thousand to a few tens of thousands ppm, the vast majority distills, but the rest of the mercury in the pyrolysis slag is present in an average concentration of 50 to 500 ppm.
• the residual mercury content of the pyrolysis slag is taken along during the washing and screening process steps (and only separated out during the electrolysis), so that these must be carried out with special precautionary measures. It would therefore be desirable in the process described above to lower the mercury level at the earliest possible stage below the generally accepted 10 ppm limit.
• EP-A-0-075 978 discloses a process for recovering metals from scrap from nickel-cadmium storage batteries, in which the organic components are removed by pyrolysis in an inert gas / oxygen atmosphere, then the cadmium is distilled off at high temperature and is condensed and a mixture of nickel and scrap iron is obtained as a residue.
• EP-A-0 075 978 does not recognize and deal with the problem of mercury contamination in the presence of batteries containing mercury in the starting mixture. It is not apparent from this patent whether the mercury is distilled off with the cadmium or is retained in the Ni-Fe scrap.
• EP-A-0 158 627 describes a process for the recovery of ferromanganese from discharged zinc-carbon-manganese oxide batteries.
• the battery scrap is melted together with coal and iron in a reduction vessel at around 1400 ° C to 1600 ° C, whereby volatilized zinc condenses on the one hand, and manganese is recovered as ferromanganese.
• the mercury content in the small batteries can be up to 3% by weight.
• the batteries are shredded and the scrap is heated to temperatures of around 600 ° before the reducing melting, similar to the pyrolysis process step described in EP-A-0 274 059.
• the mercury residue in the pyrolysis slag not specified in EP-A-0 158 627 after this first process step should therefore lie in the same value range.
• the object of the invention is therefore to improve the method mentioned at the outset in such a way that the residual mercury content after the thermal treatment is less than 10 ppm.
• the second thermal treatment of the pyrolyzed and chopped material according to the invention can either be carried out on the entire starting material or only on a part thereof, preferably the fine fraction or powder obtained by sieving.
• the possibly coarse or caked pyrolysis slag can be comminuted or loosened as required, and by adjusting the process parameters (time, temperature, stirring, gas supply, etc.) in each case according to the composition and type of the material to be treated, the person skilled in the art can use the second thermal according to the invention Treatment usually reduce the mercury residue to 0.9 to 6 ppm. According to the invention, the following materials can be subjected to the second thermal treatment:
• the larger part can also be treated thermally after sieving.
• the use of the method according to the invention is not limited to the above-mentioned solid powder and sludge from spent batteries contaminated by mercury, but can also be applied to other industrial waste containing mercury, for example raw materials and intermediate products containing mercury-amalgam, which have a manufacturing defect .
• the second thermal treatment can be carried out either under a reducing atmosphere (N 2 ) or under an oxidative (air / 0 2 ) atmosphere.
• the second thermal treatment is carried out under an oxygen-containing atmosphere, the following advantageous aspects result: a) By combining heating and oxidizing with air in the second thermal treatment, the combustible or oxidizable mixed components, such as graphite, Zn, Cd, amalgams, are oxidized and a bond with the mercury is prevented, which means that Makes it easier to suck off mercury. b) The combustion of the graphite to Co 2 causes an additional internal flushing of the material in the furnace and facilitates the removal of the mercury. c) The treated material is freed of graphite and coal residues. d) The oxidation and combustion reactions are exothermic overall, which contributes to heating and reduces the consumption of energy supplied.
• the combustible or oxidizable mixed components such as graphite, Zn, Cd, amalgams
• the material to be treated by the second thermal process step contains a considerable proportion of higher manganese oxides (Mn0 2 , Mn 3 0 4 or Mn 2 0 3 ), oxidized conditions prevail in the treated mass, even without oxygen ⁇ holding gas supply. As a result, carbon residues and also Cd and Zn are at least partially oxidized.
• the CO 2 formed contributes to the removal of the Hg, and CdO is much less volatile than metallic Cd, so that less Cd distills over. Even without oxygen supply, local excess temperatures compared to the setpoint of the furnace were found in the treated mass, which may be due to non-homogeneous distributions of MnO 2 and C and local exothermic reactions.
• the second thermal treatment is preferably carried out at temperatures around or above 600 ° C. for optimal mercury removal. Since the second pyrolysis does not depend on the first mercury being as complete as possible when using a second thermal treatment, this first pyrolysis can now be carried out at somewhat lower temperatures (400 ° C to 500 ° C) instead of the otherwise used 500 ° C to 550 ° C.
• Figure la shows a schematic flow of a preferred method according to the present invention.
• Figure lb shows the temperature-time profile in the furnace (O), and at various measuring points P in the mass of the treated powder (Pl •; P2 ⁇ ⁇ ⁇ ; P3 ⁇ *; P4 D; P5 X), with progressive heating of the furnace and without gas supply.
• Figures 2a and 2b show the temperature-time curve in the furnace (O) and at the measuring points P1-P5 at a constant furnace temperature of 600 ° C, each with air and nitrogen flow.
• Figures 3a and 3b show the temperature-time profile in the furnace () and at the measuring points P1-P5 at a constant furnace temperature of 500 ° C, each with air and nitrogen flow.
• the box marked with the reference numeral 1 symbolizes "the pyrolysis furnace. In this symbolized with 0 batteries mixture is placed therein.
• the first pyrolysis which takes place in the furnace 1 is preferably carried out at a temperature between 450 ° C-700 ° C.
• the organic substances, water, oils and most of the mercury escape here.
• the furnace is usually blown with nitrogen. This nitrogen also serves as a transport medium for the mercury vapors. All substances are removed from the furnace suctioned off and passed through an exhaust gas filtration system 3. The extracted mercury will accrue here.
• the exhaust gas filtration system is described in EPA-0 274 059, which is hereby incorporated into the description.
• the pyrolysis slag 2 is removed from the furnace 1 and fed to a shredder 4.
• the crushed pyrolysis slag is then washed at 5.
• the majority of the water-soluble salts are rinsed out.
• the water-soluble salts 6 can subsequently be removed from the water using known methods, for example crystallization.
• the shredded and washed pyrolysis slag is then separated into coarse particles 8 and fine particles or powder 10 at 7 by means of a sieve.
• the major parts consist essentially of Zn, Cu, Ni and graphite residues. Iron components, which may also be present, can be removed with a magnet 14.
• the remaining coarse parts are placed in an electrolysis bath and separated electrolytically here.
• the metals accumulating on the cathode are removed and sold to metal industry companies (arrow 13).
• the screened fine parts 10 are not fed to a powder electrolysis plant, but are fed to a second pyrolysis.
• This can take place either in the previously mentioned, batch-wise furnace 1 or in a second, continuous furnace 11 with a conveyor screw. Now that all organic substances have been carbonized in the first pyrolysis, the second pyrolysis can take place at higher temperatures, 600 ° C to 700 ° C.
• either air L or nitrogen or no gas at all can be blown through the furnace (1, 11), the greater the spontaneous gas evolution in the second pyrolysis, the smaller the amount in air, which is required as a means of transport for the transport of mercury.
• the second thermal treatment can also be carried out in the temperature range 500 ° - 600 ° C.
• the volatile fractions obtained in the second pyrolysis are in turn fed to an exhaust gas filter system which is the same or similar to that of the exhaust gas filter system 3.
• the mercury taken from the exhaust gas purification system 3 or 12 is recycled.
• a laboratory oven is set to a target temperature (600 ° C or 700 ° C). Powders from a first pyrolysis are placed in a crucible (thickness of the layer 4 cm) and placed in the oven. The experiment is static, that is, without stirring and without gas flow. Tested fabrics:
• the samples (1.7 kg) are placed in a laboratory crucible and form a layer 8 cm thick. Gas (5 liters per minute) can flow through the mass through a perforated tube. The temperatures in the samples are measured locally at several points using Ni-Cr probes.
• Figure lb shows a temperature profile without gas supply.
• the furnace is heated progressively and reaches 600 ° C within five hours. It can be seen that the powder temperature follows the oven temperature until the latter reaches 400 ° C. If the furnace temperature exceeds 400 ° C., then even higher temperatures are measured in the powder, which vary locally and can only be produced by spontaneous exothermic reactions in the mass. Locally and for a short time, a temperature in the mass can exceed the oven temperature by 120 ° C.
• FIGS. 2a, 2b, 3a and 3b show temperature profiles of pyrolyzed alkaline battery powder with air or nitrogen supply at constant oven temperatures of 600 ° C. and 500 ° C. in each case.
• the following can be seen from the pictures: If you blow air through powder treated at 600 ° C, you measure temperatures that can rise up to 830 ° C in the center of the sample. In contrast, the addition of nitrogen reduces the occurrence of excess temperatures. The temperature differences (excess temperatures compared to the furnace temperature) are smaller than without gas supply. At an oven temperature of 500 ° C you get a complex temperature profile with air supply and a temperature regulating effect with nitrogen supply. In the latter case, the temperature does not exceed 550 ° C.
• the mercury residues in the gas-treated powders were measured at least in two places (Pl and P2), Table 2 illustrates the measurement results. This means that at 600 ° C furnace temperature, the mercury can be performed satisfactorily with both air and nitrogen with the addition of gas, but that, at an furnace temperature of 500 ° C, results that are not reproducible and unsatisfactory can be achieved. both under nitrogen and oxygen supply, with a treatment time of 3 hours.
• the pyrolysis furnace of the industrial plant was used. Sieved powder from the first pyrolysis, from stocks of mixed batteries and from alkaline batteries was used. The mercury residues in these powders were 500 or 1000 ppm mercury. The loads were between 700 and 1300 kg. The batches were run under a flow of 1 cubic meter per hour of nitrogen for 30 hours. Table 6 shows that the mercury residue from all batches was satisfactorily reduced to a few ppm at oven temperatures of 700 ° C.
• thermometer 1 kg of shredded pyrolyzed thermometer was placed in the laboratory pyrolysis furnace.
• the mixture consisting essentially of glass splinters, carbon, metal parts and mercury contained an impurity of about 500 ppm mercury.
• the slag was kept at approximately 500 ° C. for three hours and permeated with 13 / h of air.
• the final weight of the slag was 940 g and the mercury concentration was 9 ppm.
• the pyrolyzed and shredded material is sieved and both the fine parts and the coarse parts are subjected to the second thermal treatment without being washed beforehand: this saves the energy for water evaporation of the washed and moist material.
• the second pyrolysis of the coarse parts (essentially Cu, Ni, Zn, Fr pieces) frees them from toxic Hg residues before further treatment, see above that this further treatment is facilitated.
• the second thermal treatment of the coarse particles is essentially faster and easier than that of the powder.

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• General Chemical & Material Sciences (AREA)
• Mechanical Engineering (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Manufacturing & Machinery (AREA)
• Sustainable Development (AREA)
• Environmental & Geological Engineering (AREA)
• Organic Chemistry (AREA)
• Life Sciences & Earth Sciences (AREA)
• Materials Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Electrochemistry (AREA)
• Metallurgy (AREA)
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• General Health & Medical Sciences (AREA)
• Toxicology (AREA)
• Business, Economics & Management (AREA)
• Emergency Management (AREA)
• Processing Of Solid Wastes (AREA)
• Treatment Of Sludge (AREA)
• Battery Electrode And Active Subsutance (AREA)

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• 1993
  • 1993-03-31 EP EP93908871A patent/EP0587867A1/de not_active Withdrawn
  • 1993-03-31 AU AU39502/93A patent/AU661395B2/en not_active Ceased
  • 1993-03-31 JP JP5517096A patent/JPH07500380A/ja active Pending
  • 1993-03-31 WO PCT/EP1993/000793 patent/WO1993020593A1/de not_active Application Discontinuation
  • 1993-03-31 CA CA002110400A patent/CA2110400A1/en not_active Abandoned
  • 1993-11-30 NO NO934344A patent/NO934344D0/no unknown
  • 1993-11-30 FI FI935368A patent/FI935368A/fi not_active Application Discontinuation

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