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
  • C22B43/00—Obtaining mercury
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B09—DISPOSAL OF SOLID WASTE; RECLAMATION OF CONTAMINATED SOIL
  • B09B—DISPOSAL OF SOLID WASTE NOT OTHERWISE PROVIDED FOR
  • B09B3/00—Destroying solid waste or transforming solid waste into something useful or harmless
  • B09B3/40—Destroying solid waste or transforming solid waste into something useful or harmless involving thermal treatment, e.g. evaporation
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B09—DISPOSAL OF SOLID WASTE; RECLAMATION OF CONTAMINATED SOIL
  • B09B—DISPOSAL OF SOLID WASTE NOT OTHERWISE PROVIDED FOR
  • B09B3/00—Destroying solid waste or transforming solid waste into something useful or harmless
  • B09B3/50—Destroying solid waste or transforming solid waste into something useful or harmless involving radiation, e.g. electro-magnetic waves
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B09—DISPOSAL OF SOLID WASTE; RECLAMATION OF CONTAMINATED SOIL
  • B09C—RECLAMATION OF CONTAMINATED SOIL
  • B09C1/00—Reclamation of contaminated soil
  • B09C1/06—Reclamation of contaminated soil thermally

Definitions

• the invention relates to a method for the recovery of heavy metals, in particular mercury, lead or cadmium from adsorbents, scrap, building rubble or soil, in which the adsorbents or waste are in a treatment chamber under a vacuum of one
• Inert gas are flowed around and heated, the gases containing heavy metal vapor arising in the treatment chamber being passed into a post-combustion chamber and heavy metal1 emerging from the exhaust gas emerging therefrom being condensed, and one
• the Adsorptions ⁇ can z. B. activated carbon, activated coke, carbon molecular sieves, zeolitic molecular sieves, plastic molecular sieves, aluminum oxide, silica gel, zeolites, diatomaceous earth.
• Such a method for the recovery of mercury is known from DE-A 32 43 813.
• the temperature in the treatment chamber is increased in stages, so that only discontinuous operation is possible.
• the object of the invention is to improve the methods of the type mentioned so that a continuous disposal of waste such as scrap, building rubble, soil and. The like. is possible by separating out heavy metals contained therein, the plant for carrying out the method being intended to make it easy to adapt to the case to be processed in terms of control technology.
• the object is achieved with respect to the method by the characterizing features of claim 1 and with respect to the system for carrying out the method by means of the characterizing features of
• the system 1 according to FIG. 1 consists of a degassing chamber 2, a high temperature chamber 14, an evaporation chamber 21 and a freezer device 20.
• the degassing chamber 2 has a conveyor device 5, by means of which waste introduced via the entry lock 3 can be conveyed through the degassing chamber 2 to a discharge lock 4.
• a conveyor 29 is assigned to the conveyor device 5, so that the weight of the material contaminated with heavy metals, such as, for. B. mercury batteries can be weighed continuously during the task.
• An arrangement of radiators 6 is provided above the conveyor device 2. By means of these radiators 6, the atmosphere in the degassing chamber 2 is heated to 250 ° C. by the energy of the electromagnetic waves introduced.
• a connection piece 7 is provided, to which an inert gas container 10 is connected by means of a line 8 with valve 9.
• the inert gas container 10 can, for. B. filled with N2.
• the inert gas flows through the degassing chamber 2 and is enriched with vapors escaping from the waste.
• Plastic-containing impurities contained in the waste such as long-chain hydrocarbon compounds or chlorinated hydrocarbons, are completely evaporated in the degassing chamber 2.
• the material slowly migrates to the material delivery section 30 of the conveyor device 5.
• This process is ended after a throughput time t which is dependent on the dissipation energy entered and the evaporable plastic parts.
• the required throughput time and the amount of dissipation energy to be contributed is determined by determined a computer, not shown, by which the valves 9, 13 and the radiator 6 are controlled.
• the emitters 6 are preferably operated to emit infrared radiation in the wavelength range from 1 mm to 780 nm.
• an exhaust pipe 11 is provided, to which a high-temperature chamber 14 is connected by means of a line 12 with valve 13.
• the high temperature chamber 14 has a burner 15 which, for. B. can be operated with propane.
• Baffles 16 are arranged downstream of the combustion chamber and serve to direct the gas mixture consisting of combustion exhaust gases and the inert gas which has been drawn off from the degassing chamber 2 and enriched with gaseous impurities.
• the burner 15 is preferably set such that a gas temperature of approximately 1400 ° C. is present in the area of the baffles 16. This makes it possible to split vapors of the wastes absorbed by the inert gas in the molecular range, so that the
• the high temperature splitting is preferably supported by introducing ozone into the combustion chamber.
• an ozone generator 31 can be connected to line 12.
• the reaction process of the splitting is accelerated by the ozone and can thus be carried out more efficiently.
• This treatment of the exhaust gas drawn off from the degassing chamber 2 means that the gas mixture emerging from the high-temperature chamber 14 can be completely inert.
• This self-inerting makes it possible to operate the evaporation chamber 21 without supplying nitrogen, but at least to limit the proportion of nitrogen to be supplied to the inert gas circuit 23 of the evaporation chamber 21.
• a heat exchanger 17 is provided, through which the gas mixture emerging from the baffles 16 flows.
• a line 18 with a fan 19 is connected, which is connected to a freezer 20.
• the gas emerging from the high-temperature chamber 14 can reach z. B. - 30 ° C to be cooled.
• the heavy metal vapor condenses out and can be fed to a heavy metal condensate container (not shown in more detail).
• the gas mixture cleaned of heavy metal vapor can be released into the atmosphere after further filtration, if necessary.
• degassed waste is introduced into the evaporation chamber 21 via the discharge lock 4.
• the waste is also subjected to electromagnetic wave energy by means of an arrangement 22 of emitters 32. It is advantageous to emit radiators 32 with alternating ones in the feed direction of the waste
• the evaporation chamber 21 is flowed through by an inert gas, preferably heated to 510 ° C., of the inert gas circuit 23 already mentioned.
• the inert gas sucked out of the evaporation chamber 21 by means of a blower 28 flows through a preheater 24 by being heated to approximately 357 ° C.
• the preheater 24 is connected to the heat exchanger 17 of the high temperature chamber 14.
• the inert gas flows from the preheater 24 in a heavy metal vapor separator 25.
• the heavy metal vapor is fed to the deep-freeze device 20, while the inert gas cleaned of heavy metal vapor flows through line 27 through a heat exchanger 26 in order to re-enter the evaporation chamber 21 after heating to 510 ° C. .
• the emitters 32 can emit electromagnetic wave energy in the high-frequency range (100 kHz to MHz range), in the medium-frequency range (0.15 to 20 kHz) or in the low-frequency range ( ⁇ 50 to 60 kHz) to 900 ° C. It is also possible to carry out this heating up to 900 ° C. by means of electromagnetic wave energy in the infrared range.
• the evaporation chamber 21 can also be surrounded by a combustion chamber fired with gas or oil, by means of which the material located in the evaporation chamber 21 is heated to 900 ° C.
• a slide 36, 37 is arranged at the entrance and exit of the evaporation chamber 21, by means of which the evaporation chamber 21 can be closed in a manner which is resistant to negative and positive pressure. Unexpected pressure peaks occurring in this evaporation chamber 21 are intercepted by a pressure relief valve 45.
• inert gas is forced through the evaporation chamber 21 by a blower 28. The gas heated in this absorbs heavy metal vapors which are discharged from the evaporation chamber 21 with the purge gas stream.
• the gas volume increasing due to the heavy metal evaporation is discharged and extracted with the aid of an ejector 46.
• the slides 36, 37 can be designed as rotary slides or rotary locks, whereby a fully automatic loading of the evaporation chamber 21 is possible. If batch operation is provided, the slides 36, 37 can be designed as flat slides.
• the cleaned waste material emerging from the outlet lock 33 is conveyed through a conveyor
• FIGS. 3 and 4 Such an embodiment is shown in FIGS. 3 and 4 for the systems 41, 42.
• the ejector 46 with frozen gas of z. B. - 30 ° C, for which a fan 48 is provided. As soon as the cold gas flow with that withdrawn from the second stage of the vaporization chamber 21
• This separator 35 can be used as a cyclone or
• the ejector 46 is operated with frozen liquid 52, which, for. B. mercury, brine, heat exchange oil, liquid nitrogen or the like. May be.
• This liquid 52 is pumped from a reservoir 53 by means of a pump 54 via a heat exchanger 55 in the circuit and in the heat exchanger 55 to z. B.> - 30 ° C cooled.
• the frozen liquid 52 is fed from the collecting container 53 to the ejector 46 by means of a pump 56 and injected therein.
• exhaust gas from the high-temperature chamber 14 is fed to the ejector 46.
• the condensate is separated in the separator 35 and returned to the collecting container 53 with the liquid of the ejector jet.
• the gas flow from the ejector 35 consisting of steam and gas residues is passed through a heat exchanger 57 arranged above the separator 35 and released into the atmosphere via a filter 38.
• a heat exchanger 57 z. B. the mercury from the gas current contained mixture of moisture and metal vapor by freezing to z. B. - 30 ° C and fed to the collection container 53.
• Excess liquid 52 such as. B. mercury in the system 42 of FIG. 4 in the collecting container 53 is discharged into another container 62.
• the evaporation chamber 21 can also be made inert by means of the exhaust gas from the high-temperature chamber 14, from which a partial flow is returned to the evaporation chamber 21 by means of a fan 58.
• the liquid 69 which contains mercury and is recirculated through the heat exchanger 55 and recooled to ⁇ 30 ° C., can also be introduced directly into the feed line 68 of the ejector 46.
• FIG. 5 shows a further embodiment of a system 43 which is particularly suitable for the decontamination of mercury-containing material. If exhaust gas emerging from the high-temperature chamber 14 has to be discharged into the atmosphere, it is filtered through a filter 38 with a
• Adsorbent performed.
• This adsorbent can e.g. B. be activated carbon. It is also possible to use carbon molecular sieves or zeolitic molecular sieves or plastic molecular sieves. Aluminum oxide, silica gel, zeolites and silica can also be used.
• the entry lock 3 there is a mill 60.
• mercury-containing wastes are ground under liquid nitrogen at temperatures below ⁇ 41 ° C.
• the frozen regrind is then introduced into the degassing chamber 2 via the entry lock 3 and in this on z. B. heated to 280 ° C.
• the resulting inert gas mixture with plastic vapors is pumped off to the high-temperature chamber 14 and is broken down therein, as already described above.
• a partial flow of the exhaust gas from the high temperature chamber 14 is via the filter 38 in the Atmosphere.
• the residual gas is reintroduced into the degassing chamber 2 via the fan 59.
• a pump 61 presses liquid mercury from the collecting container 62 into the evaporation chamber 21 before the evaporation chamber 21 is heated up, until the latter is filled.
• the pump 61 circulates mercury in the evaporation chamber 21 while the latter is being heated to approximately 200.degree. This forms Hg, Ag, Au-containing amalgam, which is pumped into the deposition chamber 39 by means of the pump 63.
• the amalgam is freed of mercury by heating the mixture to about 800 ° C.
• the deposition chamber 39 is evacuated by means of the vacuum pump 64.
• the mercury evaporates and is in the freezer 20 designed as a condenser by recooling to z. B. - 30 ° C condensed and collected in the collecting container 62.
• Au-Ag residues are removed by opening the slide 65.
• Residual scrap such as steel and coal scrap remaining in the evaporation chamber 21 is discharged after the amalgam has been completely removed and the remaining residual material has been heated to approximately 800.degree.
• residual mercury is evaporated and fed to the freezer 20 by means of a fan 66 and condensed. This mercury condensate is also discharged into the container 62.
• the residual scrap is then applied to the conveyor 47 by opening a screen slide 67 and a slide slide 68. It is possible to remove the material from the chamber 39 in the wet process, e.g. B. further digest in a nitric acid bath.

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• Engineering & Computer Science (AREA)
• Environmental & Geological Engineering (AREA)
• Thermal Sciences (AREA)
• Physics & Mathematics (AREA)
• Chemical & Material Sciences (AREA)
• Toxicology (AREA)
• General Health & Medical Sciences (AREA)
• Health & Medical Sciences (AREA)
• Manufacturing & Machinery (AREA)
• Materials Engineering (AREA)
• Mechanical Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Life Sciences & Earth Sciences (AREA)
• Soil Sciences (AREA)
• Manufacture And Refinement Of Metals (AREA)
• Processing Of Solid Wastes (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=6438676

Family Applications (1)

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Citations (3)

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• 1991
  • 1991-08-20 DE DE4127506A patent/DE4127506C1/de not_active Expired - Fee Related
• 1992
  • 1992-08-18 WO PCT/EP1992/001891 patent/WO1993004209A1/de active Application Filing

Patent Citations (3)

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