AU738103B2 - Process for splitting residues to obtain secondary raw materials - Google Patents

Description

PROCESS FOR SPLITTING RESIDUES TO RECOVER SECONDARY RAW 2

MATERIALS

3 4

DESCRIPTION

6 According to a first aspect of the invention, there is provided a process for 71 recovering secondary raw materials from rubbish and/or tailings and/or residues, 8 the process comprising: separating a fine fraction from the rubbish and/or tailings 9 and/or residues; detoxifying the fine fraction to below a predetermined level of contamination; cleaning the contaminated residue of the detoxification step from S adhering contaminants using a wet treatment step and separating them out in an 12 uncontaminated manner using a step of heavy materials separation; crushing the e 12 remainder of the rubbish and/or and/or tailings and/or residues; classifying and 13 separating into fractions and/or particle sizes the product resulting from the 14 crushing step, the fractions including a coarse fraction; alternately treating the 16 fractions with dry and wet treatment to a point at which the materials and biological i, 1 substances in the fractions are fit for immediate use; separating ferrous 17 constituents and light plastics from the course fraction and discharging the :i 18 remainder of the coarse fraction; crushing the discharged coarse fraction; 19 conveying the crushed discharged coarse fraction to a wet process and thereby cleansing from contaminants; separating the cleansed fraction into a heavy 21 fraction, a light fraction and a fibre sludge wherein the resulting separated fractions are fit for immediate use as secondary raw materials and secondary fuels.

P:AWPDOCSCRNMSPECR677143sp .do.241m07/ Part 1. Facility Section On Location for Dry Residues Unlike processes and facilities used up to this time, it would be desirable to provide a process for reducing hitherto unusable dry residues from rubbish from domestic waste and from industrial waste similar to domestic waste, which remain after separation of paper, glass, plastics, biological waste and after installation of the clearance stage "recycling centre for detoxification and removal of bulky material from the rubbish, to separate residual tailings and several reusable fractions which represent a rather large and easily useable residue fraction and waste fraction from the whole supplied residue, by properly designing the first facility already on location.

The tailings are dumped hereby over the delivery ramp with appropriate difference in elevation into the feed funnel of a mobile drum screen with a stone screen attachment having a lateral separation of 150 mm and i. a screen apefture of 25 40 mm.

o 0 1 Whereas the fine fraction is conveyed to a processing rail (9 13), 2 depending on the quality to be used as cover for waste dumps or as landscaping 3 compost, the discharged coarse fraction is dumped onto an inclined conveyor 4 oriented transversely to the discharge. An overhead belt magnet separator is placed before the inclined conveyor for separating ferrous metals (and 6 entrained plastic foils) into a container for ferrous metals if desired, with the 7 addition of air separators (14) for separating the plastic foils.

8 9 At the end of the inclined conveyor the waste material is inspected on a sorting table for contaminants, removing those materials which alleviate 11 subsequent process flows, and also removing those materials with adhering dirt .12 which do not hinder utilization on location rims, broken glass, textiles).

13 14 An inclined conveyor 2 on which the residue mass flow is conveyed, runs into the coarse fraction container with a compaction suitable for 16 transport and particularly adapted to facilitate rail transport (40 tons per car 13 17 tons max. per ACTS-compatible container).

18 19 The fine fraction (9 13) is guided through a small drum screen with a mesh size of 10 15 mm for separating the coarser middle fraction, with the 21 middle fractiOn conveyed to a middle fraction container The fine fraction 22 residue flow is directed once more over a metal or induction separator (11) lr 1 before being shipped in a truck-compatible container (12) to a proximate 2 intensive rotting stack (13) located, for example, at existing or former waste 3 dumps or at a similar transfer point, where the residue is used locally as cover or 4 landscaping material. Light plastic materials are separated from the ferrous metals with the help of an air separator (14).

6 7 This combination reduces the tailings by more than 40% of the prior 8 delivery weight, the biogenic fraction is used on location, secondary raw 9 materials suitable for local use are immediately conveyed to raw material 0io processors. Only the tailings are shipped to a stationary facility for further 11 processing. The stationary facility can essentially be located at any distance.

12 13 Part 2. Facility Section Stationary Dry Processing Portion 14 The residue considered screen overflow is dumped from the container 16 onto the discharge surface is then after a brief visual control inspected 17 by sorting personnel for problematic materials, bulky contaminants such as 18 carpet composite, and then discharged into the flat bunker The flat 19 bunker (16) is provided with a ventilation system with air ducts which are connected to a bio-filter 21 22 An inclined conveyor (17) runs from the bunker upwards in elevation to a sorting stage an air separator (18) conveys light materials with a large 2 surface area, in particular plastic foils, to a plastic film container on top, 3 blown-in air is extracted through a biofilter (20) by suction. In addition to the 4 plastic foil air separation, 4 additional contaminants which are not suitable for post-treatment and do not urgently require the subsequent wet shredding and 6 washing stage, are extracted through manual sorting or machine sorting on the 7 sorting stage and conveyed through discharge chutes to mobile containers.

8 9 On the sorting stage, the residue is proportioned in height and directed 0io underneath an overhead plate magnet (23) for separating in particular small 11 metal pieces and problematic metallic materials such as batteries.

12 13 After this detoxification step, the size is reduced first. Care is taken that a 14 screw mill (24) does not destroy the hazardous tailings, but rather enables water in the following washing and shredding stage to attacks the crushed material 16 An inclined conveyor 2 (25) conveys the crushed residue to wet processing 17 18 Unlike conventional conditioning processes of this type, the present 19 process emphasizes screening, sorting and sizing as well as separation of residue mass flows so as to properly design the process as a conditioning step 21 for the subsequent stages in the process chain.

I Analyses at the sorting table and of the weights of the residual flows have 2 shown that contaminants, such as ski boots made from glass fiber reinforced 3 plastic, textiles, thermoset plastics, non-metals and non-ferrous metals, still 4 account for more than 20% of the residue flow. These contaminants cannot be shredded into fibers in the wet shredding process. On the other hand, the 6 processing facilities do not require extremely pure materials, since the 7 processing facilities will shred and condition the materials themselves. Also 8 conceivable is a pre-treatment to obtain granulate in a fine shredder (Part 3/4, 9 facility 25), before a secondary raw material conditioned in this manner is shipped to the user.

11 12 Part 3/4 Facility Section Stationary, Wet Treatment Portion Plus Additional 13 Conditioning for Use 14 The visually post-inspected (26) residue flow is conveyed to a pulper 1 16 (27) to be used for shredding reinforced fibers as well as for washing and 17 dislodging of dirt adhering those materials (plastics, metals, which cannot be 18 separated into fibers. Consequently, a shredder wheel for fibers is an important 19 component and selected from a product line of pulpers. The most important element for aqueous separation of materials is the special coil with a 3 mm fiber 21 hole bottom-perforation and a light fraction discharge system (31, 32) and a 22 heavy fraction discharge 1 (28) with a double material lock.

I The heavy fraction lock is connected to a recess in the inclined bottom of 2 the trough, wherein rrrainly the heavy parts like rocks, porcelain, ceramics, small 3 metallic pieces and glass are mixed and then separated by centrifugal forces.

4 When the upper lock gate is closed and the lower lock gate is opened, the heavy fraction is dumped into a mobile container and conveyed for dewatering and 6 further processing.

7 8 The sludge fraction is shredded again and pumped with the help of an 9 efficient pumping station via a hydrocyclone 1 (29) to the fiber sludge io container 1 positioned low and from there to the compact sludge treatment 11 unit 1 (33) which includes a flocculation and dewatering function. The process 12 water is pumped back with suitable pumps and the fiber sludge cake with 13 about 30% dry solid upon discharge is first composted under steam for killing 14 germs, fungus, viruses and spores, then turned over and strained of residues Is until the sludge is ready for sale (53, 54, 55). Optionally the fiber sludge 16 cake can be use to produce a substrate for cultivating mushrooms. The 17 granulate residue from the hydrocyclone, on the other hand, is conveyed to the 18 recycling process for construction debris (BR).

19 The biogas production is available as an option only with excellent 21 fermentatiorT test parameters, followed by condensing or discharging of the 22 fermented suspension fluid which is the major constituent of the wet fermentation I process.

2 3 The light fraction is treated by discharging the light fraction either through 4 light fraction strainers or through the open heavy particle lock after a second rinse with 5000 liters! 4% dry solid directly into the light fraction container 1 (32) 6 in the lower position the first shredding and discharge process was carried out 7 with 10000 liters and about 5% dry solid. The strained material is removed from 8 the strainings basket (31) by lifting, rotating and opening at the option Second 9 Rinse, and conveyed to a mobile container for dewatering The option Discharge of Upper Light Fraction is carried out with the system component ii LOHSE wet waste dislodging unit, German Patent No. P 4235197-27 by a 12 skimming process.

13 14 The substances which can produce fine strainings from waste water treatment plants, are dissolved in a similar manner. Prior removal of 16 contaminants by a dry method is here not required.

17 18 The fine strainings which show, as demonstrated by the analysis 19 commissioned by the applicant, a more than an order of magnitude improvement in heavy metal contamination as compared to the sludge from the same facility, 21 are conveyed from the silo supplying the fine strainings (39) to the inclined 22 conveyor 2 (40) and moved to the second material dislodging line next to the dry 7 Streated material (41).

3 The heavy particle discharge 2 hydrocyclone 2 fiber sludge 4 intermediate container 2 strainer basket 2 (46) and the sludge treatment compacting unit 2 (47) as well as the sludge cake discharge 2 (48) and the 6 sludge utilization option Mushroom Substrate (49) are constructed as a mirror 7 image of the unit for the dry-fed material. Designed in the same manner are air 8 separators for separating glass (54) if construction debris (BR) is supplied, and 9 the option for a simple biogas plant depending on the feed stock. Commonly io required post-treatment steps on both rails are the facility light fraction fine II shredder (50) after the light fraction is discharged from the container, and -i2 dewatering of the light fraction For further conditioning, these steps are 13 followed by an optional hydrocyclone (31) for plastics, and thereafter already by 14 the processing steps of the facility section Utilization (part Among those steps is the induction separator for non-ferrous metals (52) and the removal in the form 16 of conditioned secondary raw material Similarly, the injection of steam (54), 17 turning over the stack (54) and the straining process (55) for manufacturing 18 finished composts 19 Commonly used is also the process water return of a modular facility 21 unit of part 3/4. Pumps (34) return process water from the sludge treatment 22 compacting units 1 and 2 into the process water tank The tank is able to 8 hold the entire quantity of process water contained in the loop for starting the 2 operation and includes a supply line for fresh water with the sediments 3 discharged at the lower end of the tank which extends upwardly to the double 4 lock and is shaped like a cone. After the upper lock is latched and the lower lock is opened, a mass of the sediment of 0.5 m 3 flows at each dissolution step from 6 the double lock into a pre-filtration filter bag unit (38).

7 8 Cleaned process water is returned to the process water tank. 10,000 liters 9 and subsequently 5,000 liters of process water, and also the 1,500 liters of added fresh water are withdrawn at each dislodging step. The process water 11 loop can be fully balanced for a compost bed with percolation tank in 12 interconnected facilities, except for the contribution from evaporated and 13 condensed water. All the process water is carried in the waste water loop. A 14 process water bypass for protecting the return and pump loop should nevertheless be provided, also intermediate tanks with overhead water 16 feed (ZW).

17 18 The remaining dry-fed materials, such as screen residues, soiled plastics 19 and screened refuse, are treated similarly to the materials on the dry treatment rail; in the case of wet waste materials, treatment is analogous to the wet 21 treatment rail. Fermentation tests suggest the implementation of the additional 22 option biogas plant or conveyance to a rotting (faulschlamm) tower 1 The processing path for fiber sludge compost is linked to intermixing with 2 shredded bark. The processing path of the remaining secondary raw 3 materials is selected such that the secondary raw materials are clean when 4 they leave the facility and can be returned to the material cycle either immediately or after a brief treatment in the user facilities. Mixed plastics which 6 cannot be separated further following the hydrocyclone for plastics, are shipped 7 out for recovering raw materials. Hazardous materials are handed over to an 8 authorized waste disposal unit.

Throughout this specification and the claims which follow, unless the context requires otherwise, the word "comprise", or variations such as "comprises" or S "comprising", will be understood to imply the inclusion of a stated integer or group of integers or steps but not the exclusion of any other integer or group of integers or steps.

*o o oo, o oo *o o 0 Discharge ramp/ transfer station 1 Rock grate 2 Large drum screen, mobile 3 Overhead belt magnet separator 4 Ferrous metal container Inclined conveyor belt 1 6 Control screening for contaminants 7 Inclined conveyor belt 2 8 Coarse fraction container 9 Small drum screen, mobile Middle fraction container 11 Metal induction separator 12 Fine fraction container 13 Rotting stack 14 Air separator T Transport to section 2 S Secondary raw material processing Discharge surface 16 Flat bunker 17 Inclined conveyor belt 1 18 Air separator 19 Plastic Film container 21 22 23 24 26 27 S 28 29 31 32 33 34 36 37 38 Biofilter with exhaust channels Sorting stage with 5 contaminant Containers and discharge chutes Height proportioning of residue flow and separation of small ferrous particles Screw mill Inclined conveyor belt 2 Secondary raw materials To section 3/ wet treatment stage Inclined feed conveyor visual and sensor control Pulper 1 Heavy particle discharge 1 (container) Hydrocyclone 1 Fiber sludge intermediate container 1 Strainings basket 1 and strainings discharge Light fraction intermediate container 1 Sludge treatment compacting unit 1 Process water pump and thick matter pump Fiber sludge cake discharge 1 (container) Process water tank Sludge recovering option substrate for cultivating mushrooms Filter bag pre-filtering unit 39 41 42 43 44 46 47 48 49 S 50 51 52 53 54 56

K

S

B

BR

Fine strainings feed silo Inclined conveyor belt 2 Pulper 2 Heavy fraction discharge 2 (container) Hydrocyclone 2 Fiber sludge intermediate container 2 Light fraction dewatering after discharge Strainings basket 2 Sludge treatment compacting unit 2 Fiber sludge cake discharge 2 (container) Sludge recovering option substrate for cultivating mushrooms Light fraction fine shredder Recovering option hydrocyclone for plastics Induction separator for non-ferrous metals Rotting stacks for killing germs with steam Stack turner and bark mixer Compost strainer drum similar to 9, Part 1 Air separator Marketable composts Secondary raw materials Option-biogas plant or rotting container Construction debris recycling

Claims (4)

1. A process for recovering secondary raw materials from rubbish and/or tailings and~or residues, the process comprising: separating a fine fraction from the rubbish and/or tailings and/or residues; detoxifyring the fine fraction to below a predetermined level of contamination; cleaning the contaminated residue of the detoxification step from adhering contaminants using a wet treatment step and separating them out in an uncontaminated manner using a step of heavy materials separation; crushing the remainder of the rubbish and /or tailings and/or residues; classifying and separating into fractions and/or particle sizes the product resulting from the crushing step, the fractions including a coarse fraction; alternately treating the fractions with dry and wet treatment to a point'at which the materials and biological substances in the fractions are fit for immediate use; separating ferrous constituents and light plastics from the coarse fraction and. discharging the remainder of the coarse fraction; crushing the discharged coarse fraction; conveying the crushed discharged coarse fraction to a wet process and thereby ::cleansing from contaminants; separating the cleansed fraction into a heavy fraction, a light fraction and a fibre sludge wherein the resulting separated fractions are fit for inmmnediate use as secondary raw materials and secondary fuels.

2. A process as claimed in Claim 1, characterised in that in a first section of a plant for dry residues a) on site, at a delivery point or at a regional transfer station, in a mobile combination of screening and separation of dry input material such as rubbish tailings, screening residues from composting facilities, soiled plastics, and old rubbish, firstly bulky material larger than 150 mm. is separated through a rock screening front attachment on a mobile drum screen and is conveyed to a breaking process resulting in moderate sized pieces, with a tearer for opening bags, or with whole closed garbage RA~i~ags- with rubbish tailings being returned to the supplier, b) the fine fraction and middle fraction, which is mostly biogenic, with a particle size of less than 40 mm/25 mm is separated from the coarse fraction by the mobile- drum sieve, c) the middle fraction, of 10/15 mm to 25/40 mm, which remains after a second fine screening of the fine fraction, is filled into containers suitable for rail transport, d) the fine strainings from the second fine screening process are conveyed to a metal induction separation operation and then to an intensive rotting stack and, depending on their quality, are used in landscaping after being matured, e) the coarse fraction, after the discharge conveyor for the coarse residues, ferrous articles are extracted by' rieans of an overhead magnetic sepaiator having a gear, the magnetic separator being at least 1m long and oriented parallel to the longitudinal direction of the conveyor, the magnetic separator being arranged across the width of another conveyor running transversely to the'magnetic separator, the ferrous articles being discharged at I *the end of the gear at the end of the magnetic separator, together with the entrained plastic sheets, into a ferrous metal container provided for the purpose, and S S° f) the plastic sheets are separated from the ferrous metals in the second screening process or with the assistance of air separators, g) the mass flow of the coarse fraction residue from e) is discharged from the trough conveyor onto a mobile checking and sorting table, where a first visual check is carried out for contaminants which can be recycled in the region or which also can either cause odour emissions during transport or can reduce subsequent material quality.

3. A process as claimed in Claim 2, characterised in that in a second section of the plant for dry residues h the mass flow of residue from the first section is conveyed on site to a housed fsationary plant and discharged onto a large discharge area, where immediately recognisable large contaminants are identified and collected separately in containers for valuable substances, whereas the remaining residues are dumped into a flat bunker provided with exhaust suction and filters for the exhausted air through biofilters, i) then, a two-part inclined conveyor having various controllable speeds and a manual stop cord to be operated by the sorting personnel is adapted to quantitatively proportion the mass flow of residue, j) and then the residue is transported to a raised sorting platform which is provided with a lateral blower air separator for discharging large-surface-area plastic sheets into a first discharge chute with a mobile container provided beneath it, k) for additional contaminants there are provided discharge chutes and, thereunder, mobile containers for conveying the contaminants for immediate use or to a further conditioning stage on site, 1) the mass flow of residue stored after the sorting process, together with the middle fraction from part are conveyed beneath an overhead Fe plate magnet to extract small residual ferrous metal pieces and problem residues before final crushing prior to the wet treatment stage, m) from the mass flow of residue from step 1) the large and crushed pieces are opened up all over by means of a screw mill and exposed to the dissolving power of subsequently applied water, and larger pieces are generally reduced to palm-of-the- hand size. S 4. A process as claimed in Claim 3, characterised in that in a third section of the plant for dry residue n) the mass flow of residue from the second part of the dry stationary treatment is fed by way of an inclined conveyor belt into a high consistency chopping type pulper filled with water, with a ratio of 95 parts water to 5% residue-mass, and the crushed P A4 still slightly soiled dry-matter mixture is classified according to the density of the 17 particles, material which can be separated into fibres is so separated by stirring and ripping, and dirt particles are dislodged, o) the trough bottom trough rim transition is formed at an angle of 30-45% for discharging the heavy matter drifting from the feed stock to the trough rim, due to the centrifugal force, through a recess in this inclined surface so that the heavy material has the same size of at least 0.5 m 3 sluice volume between the upper and lower sluice gates, and can be discharged with an opening and closing mechanism, p) the fibre sludge which is drawn by a pump through the 3 mm holes of the perforated bottom plate is then withdrawn by way of a hydrocyclone and from there into an intermediate fibre sludge container, from there into a sludge treatment compacting unit, is then pressed to about 30% dry substances, and then conveyed to a fibre sludge cake stack together with the pressed fibre sludge cake from the same wet process for wet residues of the fine strainings from sewage treatment plants and then conditioned further, S:0. q) the light materials which are free of dislodged dirt particles and cannot be separated into fibres, are then mixed, in a second post-rinse process, with precleaned 0 process water in a ratio of 95 parts of water to 5 parts of light fraction with adhering fibres and discharged, through a branch of the heavy-matter sluice, into an intermediate light-fraction container with a strained-matter basket, and then dewatered and conveyed off for additional conditioning with water, oo* r) germs, viruses, fungi, spores, present in the fibre sludge cake Si-- generated by the process according to step p) and by the ongoing pre-filtration of the processed water from the process water tank which has a cylindrical shape with a conico-cylindrical part running downwards to a double sluice for suspended matter with a volume of 0.5 m 3 allowing withdrawal of the suspended sludge through a filter bag system, are destroyed by steam injected into the stack by a mobile steam system, after composting of the combined fibre sludge cake, s) the same process used for tailings is also used for dry residues from screening Spants, from composting plants and rubbish processing, up to step r), 18 t) soiled plastics from collecting containers for plastics and compound materials are processed starting with crushing in the screw mill in accordance with step m), unless the supplier has already performed a similar pre-treatment, u) fine strainings and sand-catcher residues from sewage treatment plants are processed by directly conveying these materials into the pulper in accordance with step n). A process as claimed in the foregoing claims, characterised in that in a fourth section of the plant v) the primary goal is processing into marketable secondary raw materials to the greatest extent possible and the making available and interinediate storage of clean residues until picked up by the user, whereby through the two-step wet treatment of the light fraction the plastics having a density of less than 1 g/cm 3 or heavier than 1 3 g/cm 3 are separated out, and at the same time its hot value rises, as a result of contamination reduction to 30000 kJ/kg Hu. w) oversize particles from the hydrocyclone pass through an induction separator to separate out all the metals, whereas the non-metallic overflow is directed to the construction debris recycling, and the metallic overflow is directed to the metal recycling, x: in the cleaned heavy fraction, broken glass is separated from rock particles by means of air separators, and non-ferrous metals are extracted by means of a separator for non-ferrous metals, y) the purified light-fraction mixture is dried with a separator and finely shredded, and the granulate is separated into light plastics for materials recycling, and other plastics and residual contaminants for raw-materials recycling, 19 z) the pressed fibre sludge compost is either conveyed to a rotting stack, treated with steam, turned over, and, after the hot phase, finely strained to remove residual contaminants and mixed with bark until matured, or aa) the pressed fibre sludge compost is conditioned to attain a suitable K-N-P (potash-natron-phosphorous) ratio with a dry matter content of 32 to 38% for use as a substrate for cultivating mushrooms, bb) only a mixture with the fibre sludge cake from fine strainings and the fibre sludge cake from the fine fraction of dry residues in a ratio of at least 1:1 is selected, in order to stay below the limit values for garden compost.

6. Processes for recovering secondary raw materials from rubbish and/or tailings and/or residues, substantially as hereinbefore described with reference to the drawings. DATED this 18th day of July, 2001 WALTER FELBER By its Patent Attorneys DAVIES COLLISON CAVE 9o. o