CA2215409A1 - Reuse of metallurgical fines - Google Patents
Reuse of metallurgical fines Download PDFInfo
- Publication number
- CA2215409A1 CA2215409A1 CA 2215409 CA2215409A CA2215409A1 CA 2215409 A1 CA2215409 A1 CA 2215409A1 CA 2215409 CA2215409 CA 2215409 CA 2215409 A CA2215409 A CA 2215409A CA 2215409 A1 CA2215409 A1 CA 2215409A1
- Authority
- CA
- Canada
- Prior art keywords
- slurry
- fines
- agglomerates
- carbon
- dust
- 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.)
- Abandoned
Links
- 239000002002 slurry Substances 0.000 claims abstract description 54
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims abstract description 28
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 28
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims abstract description 20
- 229910052799 carbon Inorganic materials 0.000 claims abstract description 20
- 239000002699 waste material Substances 0.000 claims abstract description 18
- 239000012876 carrier material Substances 0.000 claims abstract description 15
- 229910001385 heavy metal Inorganic materials 0.000 claims abstract description 11
- 239000007924 injection Substances 0.000 claims abstract description 6
- 238000002347 injection Methods 0.000 claims abstract description 6
- 238000000034 method Methods 0.000 claims description 37
- 239000000463 material Substances 0.000 claims description 28
- 229910052751 metal Inorganic materials 0.000 claims description 20
- 239000002184 metal Substances 0.000 claims description 20
- 239000000428 dust Substances 0.000 claims description 19
- 238000005096 rolling process Methods 0.000 claims description 19
- ODINCKMPIJJUCX-UHFFFAOYSA-N Calcium oxide Chemical compound [Ca]=O ODINCKMPIJJUCX-UHFFFAOYSA-N 0.000 claims description 17
- 229910000831 Steel Inorganic materials 0.000 claims description 14
- 239000000047 product Substances 0.000 claims description 14
- 239000010959 steel Substances 0.000 claims description 14
- 239000010881 fly ash Substances 0.000 claims description 13
- 238000006243 chemical reaction Methods 0.000 claims description 12
- 238000010891 electric arc Methods 0.000 claims description 11
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N Iron oxide Chemical compound [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 claims description 10
- 238000002156 mixing Methods 0.000 claims description 10
- 235000012255 calcium oxide Nutrition 0.000 claims description 9
- 239000007789 gas Substances 0.000 claims description 9
- 239000000292 calcium oxide Substances 0.000 claims description 8
- 238000010310 metallurgical process Methods 0.000 claims description 7
- 150000002739 metals Chemical class 0.000 claims description 7
- 239000000654 additive Substances 0.000 claims description 6
- 230000000996 additive effect Effects 0.000 claims description 6
- 239000007795 chemical reaction product Substances 0.000 claims description 6
- 239000003546 flue gas Substances 0.000 claims description 6
- 239000011236 particulate material Substances 0.000 claims description 6
- 238000007873 sieving Methods 0.000 claims description 5
- 235000019738 Limestone Nutrition 0.000 claims description 4
- 238000005275 alloying Methods 0.000 claims description 4
- 229910001861 calcium hydroxide Inorganic materials 0.000 claims description 4
- 239000006028 limestone Substances 0.000 claims description 4
- 239000002245 particle Substances 0.000 claims description 4
- 239000000126 substance Substances 0.000 claims description 4
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 claims description 3
- 229910052791 calcium Inorganic materials 0.000 claims description 3
- 239000011575 calcium Substances 0.000 claims description 3
- AXCZMVOFGPJBDE-UHFFFAOYSA-L calcium dihydroxide Chemical compound [OH-].[OH-].[Ca+2] AXCZMVOFGPJBDE-UHFFFAOYSA-L 0.000 claims description 3
- 239000000920 calcium hydroxide Substances 0.000 claims description 3
- 238000004140 cleaning Methods 0.000 claims description 2
- 238000002485 combustion reaction Methods 0.000 claims description 2
- 239000002803 fossil fuel Substances 0.000 claims description 2
- 239000004411 aluminium Substances 0.000 claims 2
- 229910052782 aluminium Inorganic materials 0.000 claims 2
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims 2
- 239000002173 cutting fluid Substances 0.000 claims 1
- 239000003500 flue dust Substances 0.000 claims 1
- 238000003754 machining Methods 0.000 claims 1
- 238000012958 reprocessing Methods 0.000 claims 1
- 239000004571 lime Substances 0.000 abstract description 10
- 235000008733 Citrus aurantifolia Nutrition 0.000 abstract description 9
- 235000011941 Tilia x europaea Nutrition 0.000 abstract description 9
- 229910052742 iron Inorganic materials 0.000 description 10
- 239000003077 lignite Substances 0.000 description 9
- 239000002893 slag Substances 0.000 description 9
- 239000003245 coal Substances 0.000 description 8
- 239000000571 coke Substances 0.000 description 8
- 238000000605 extraction Methods 0.000 description 6
- 150000002500 ions Chemical class 0.000 description 6
- 238000006722 reduction reaction Methods 0.000 description 6
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 5
- 239000000203 mixture Substances 0.000 description 5
- 239000011701 zinc Substances 0.000 description 5
- 238000005187 foaming Methods 0.000 description 4
- 239000004033 plastic Substances 0.000 description 4
- 229920003023 plastic Polymers 0.000 description 4
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 description 3
- 239000002006 petroleum coke Substances 0.000 description 3
- 238000005245 sintering Methods 0.000 description 3
- 229910052725 zinc Inorganic materials 0.000 description 3
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 2
- 239000005864 Sulphur Substances 0.000 description 2
- RHZUVFJBSILHOK-UHFFFAOYSA-N anthracen-1-ylmethanolate Chemical compound C1=CC=C2C=C3C(C[O-])=CC=CC3=CC2=C1 RHZUVFJBSILHOK-UHFFFAOYSA-N 0.000 description 2
- 239000003830 anthracite Substances 0.000 description 2
- 235000011116 calcium hydroxide Nutrition 0.000 description 2
- 239000004568 cement Substances 0.000 description 2
- 239000003250 coal slurry Substances 0.000 description 2
- 239000000446 fuel Substances 0.000 description 2
- 238000000227 grinding Methods 0.000 description 2
- 239000010453 quartz Substances 0.000 description 2
- 238000000926 separation method Methods 0.000 description 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N silicon dioxide Inorganic materials O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- 239000012899 standard injection Substances 0.000 description 2
- CWYNVVGOOAEACU-UHFFFAOYSA-N Fe2+ Chemical compound [Fe+2] CWYNVVGOOAEACU-UHFFFAOYSA-N 0.000 description 1
- 235000002918 Fraxinus excelsior Nutrition 0.000 description 1
- YFONKFDEZLYQDH-OPQQBVKSSA-N N-[(1R,2S)-2,6-dimethyindan-1-yl]-6-[(1R)-1-fluoroethyl]-1,3,5-triazine-2,4-diamine Chemical compound C[C@@H](F)C1=NC(N)=NC(N[C@H]2C3=CC(C)=CC=C3C[C@@H]2C)=N1 YFONKFDEZLYQDH-OPQQBVKSSA-N 0.000 description 1
- 241000749985 Nites Species 0.000 description 1
- 241000282320 Panthera leo Species 0.000 description 1
- 241000193803 Therea Species 0.000 description 1
- 238000005299 abrasion Methods 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 239000002956 ash Substances 0.000 description 1
- 239000000440 bentonite Substances 0.000 description 1
- 229910000278 bentonite Inorganic materials 0.000 description 1
- SVPXDRXYRYOSEX-UHFFFAOYSA-N bentoquatam Chemical compound O.O=[Si]=O.O=[Al]O[Al]=O SVPXDRXYRYOSEX-UHFFFAOYSA-N 0.000 description 1
- 239000011230 binding agent Substances 0.000 description 1
- 239000006227 byproduct Substances 0.000 description 1
- 229910000019 calcium carbonate Inorganic materials 0.000 description 1
- 235000019504 cigarettes Nutrition 0.000 description 1
- ZGDWHDKHJKZZIQ-UHFFFAOYSA-N cobalt nickel Chemical compound [Co].[Ni].[Ni].[Ni] ZGDWHDKHJKZZIQ-UHFFFAOYSA-N 0.000 description 1
- 238000007906 compression Methods 0.000 description 1
- 230000006835 compression Effects 0.000 description 1
- 239000000470 constituent Substances 0.000 description 1
- 239000010459 dolomite Substances 0.000 description 1
- 229910000514 dolomite Inorganic materials 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000011156 evaluation Methods 0.000 description 1
- 239000013505 freshwater Substances 0.000 description 1
- 238000000915 furnace ionisation nonthermal excitation spectrometry Methods 0.000 description 1
- 238000005469 granulation Methods 0.000 description 1
- 230000003179 granulation Effects 0.000 description 1
- 238000001033 granulometry Methods 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 239000004615 ingredient Substances 0.000 description 1
- VBMVTYDPPZVILR-UHFFFAOYSA-N iron(2+);oxygen(2-) Chemical group [O-2].[Fe+2] VBMVTYDPPZVILR-UHFFFAOYSA-N 0.000 description 1
- 238000009847 ladle furnace Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 229910044991 metal oxide Inorganic materials 0.000 description 1
- 150000004706 metal oxides Chemical class 0.000 description 1
- 239000002923 metal particle Substances 0.000 description 1
- 239000003921 oil Substances 0.000 description 1
- 239000008188 pellet Substances 0.000 description 1
- 238000005498 polishing Methods 0.000 description 1
- 230000009257 reactivity Effects 0.000 description 1
- 238000004064 recycling Methods 0.000 description 1
- 230000000717 retained effect Effects 0.000 description 1
- 239000004576 sand Substances 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- 239000010703 silicon Substances 0.000 description 1
- 239000003039 volatile agent Substances 0.000 description 1
- 238000005406 washing Methods 0.000 description 1
- 239000002023 wood Substances 0.000 description 1
- 235000013618 yogurt Nutrition 0.000 description 1
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
- C22B1/00—Preliminary treatment of ores or scrap
- C22B1/14—Agglomerating; Briquetting; Binding; Granulating
- C22B1/24—Binding; Briquetting ; Granulating
- C22B1/242—Binding; Briquetting ; Granulating with binders
- C22B1/244—Binding; Briquetting ; Granulating with binders organic
- C22B1/245—Binding; Briquetting ; Granulating with binders organic with carbonaceous material for the production of coked agglomerates
-
- 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
- C22B1/24—Binding; Briquetting ; Granulating
- C22B1/242—Binding; Briquetting ; Granulating with binders
- C22B1/243—Binding; Briquetting ; Granulating with binders inorganic
-
- 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
- C22B7/02—Working-up flue dust
-
- 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
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Geology (AREA)
- Life Sciences & Earth Sciences (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Manufacturing & Machinery (AREA)
- Environmental & Geological Engineering (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Geochemistry & Mineralogy (AREA)
- Inorganic Chemistry (AREA)
- Manufacture And Refinement Of Metals (AREA)
- Processing Of Solid Wastes (AREA)
Abstract
Waste material containing heavy metals are mixed with oily mill scale or with reduced iron or fines and with a fine grained carrier material having a low density until a crumbly mixed product results, of which a fine fraction of between 0 and 6 mm in grain size is sievable for injection into a metallurgical furnace. Water may be added to the mixed product using wet carbon-containing slurries. Lime-containing dusts may be added.
Description
W 096/31630 PCT/~9G/00821 R~US~ OF METALLURGICAL FINES
The invention relates to a method of use of a wide range of metal Cont~inin~ m~t~ lc which are otherwise used with ~liffi~lllty or just dumped as waste.
One suitable rnaterial is iron ore fine dust. This is difficult to dispose of. During pelletising fine ores having a grain diameter of under about 0.2 rnm are wetted and mixed with binders, e.g. bentonite, to form lu~s. The pellets are subjected to flame hardening or sintering because this is the only way in which such fines can only be used in a subsequent m~t~ lrgical process. This is similar to the l.le~ ion of fines by direct reduction. known as the names of COREX ~ MIDREX ~ or HYL~. For example in the case of the MIDREX~ process the fine ore is acted upon by reduction gases in fllli(1iced bed reactors at te~ c.~Lul~s between 500 and 800~C. The reduction gases contain H2 and CO and also CO2, H2O~ CH4 and N2 . Ple~ ion takes place in a series of fllli~liced bed reactors~ connected in series, in which the degree of reduction increases from reactor to reactor to reach values of mt-t~llic~tion of between 92 and 94% at the exit of the last fluidised bed reactor. The fines reduced in this manner are then hot briquetted in order to obtain the lump form which is necessary for the subsequent metallurgical process. Both during such sintering and during ~,lc~al~ion of the fines. ferrous dusts accumulate~ which are very fine and extremelv reactive. The CA 0221~409 1997-09-29 dusts also contain proportions of non-converted carbon. Such fines cannot be blown or injected into a metallurgical furnace because they have too high a density.
Other heavy metal cu~ ;i.;,.g dusts or slurries are produced as by-products in the m~ntlf~ctnre and processing of high quality steels. By high quality steel is meant a grade of steel which is intP.nclecl generally for heat tre~tm~nt such as hardening and te~ering. High quality steel has a higher purity than quality or basic steel (cf.
Brockhaus. NaturwissPn~.h~ften und Technik (Natural Science and Technology), special edition 1989, volume l, key word). Such steels are produced in electric arc furnaces from steel scrap and alloying conctit~l.o.nt~ The dust contained i~ the smplting gases is very finely divided and has a high specific weight more than 4 grams per cubic cPntimP.tre. The dust is separated in the electric filters installed beyond the electric furnace. It is also usual to wash out the dust from the .cmelting gases using water to produce a heavy metal co-~ g slurry. The scrap charge usually contains zinc which evaporates at the high temperatures in the mPt~llnrgical vessel and is deposited in the flue gas. These dusts (loaded with the heavy metal zinc) from dry dust extraction or slurries in the case of wet dust extraction can only be deposited at special dumps or must be subjected to expensive separation measures.
For the separation ~ ~aLiOn process of this kind of Zn-loaded dusts or slurries it is of great economic advantage if the Zn content is enriched to over ~5% e.g. 40% or more bv recycling.
W 096131630 PCT/GB~"~CQ~1 High quality steel may be treated in a rolling mill. In this case an extremely heavy rolling mill scale slurry results~ which besides the metallic components also contains ul;Lies in lump form from metal parts, orgar~ic material or plastics. Larger pieces of metaL such as screws. and cle~ning rags, cigarette ends and working gloves, yoghurt cartons and plastic bags can also be dumped by mtidy workmen in the rolling mi'il scale slurry.
All metal dusts and slurries arising during the production of basic, quality and high quality steel are finely divided (fine granulometry in the grain size range of a few microns up to 1 mm) and contain alloying metals. These alloying metals include chiefly chromillm, cobalt nickel, lead, m~nganese7 t-mg.ct~n~ ;.. , v~n~ m, zinc and molybdenu~ which are added to the individual grades of steel in differing amounts according to pre-set recipes and together with the iron, are responsible for the heaviness of the dusts and slurries. Although these dusts and slurries contain valuable sllbst~nces it has not been possible to reclaim and re-use these substances to a s~ticfactQry extent because of their inherent fineness and heaviness. In many cases the dusts c~..l~;..;..~ valuable substances are dumped but this is bad for en~ o.... ~-.l~l protection and wasteful.
~ It is one object of this invention to provide a method of recovering the valuable components of a wide variety of waste materials and introducing them in a particularly convenient way into a metallurgical vessel for re-use.
CA 0221~409 1997-09-29 W 096/31630 PCT/~b9C1'~.~21 According to the invention in one aspect there is provided a method of treating a waste f material cont~ining heavy metals. the method comprising mixing the waste material and a relatively less dense particulate material cont~ining metal oxide material and water so as to cause an exothermic reaction and thereby for_ relatively dry agglomerates;
sieving the agglomerates to isolate those having a size in the range of from about Omm to about 6mm; and pneum~ti~lly injecting the isolated agglomerates into a m~t~lhlrgical vessel Co,.l~;..i"g molten metal and under a reducing atmosphere.
The oxide material may be burnt lime or directly reduced iron. Most preferably the agglomerates are injected with carbon (which is required for other purposes in the m~t~ lrgical vessel such as a reduction reaction). The carbon may be provided from a variety of sources and may already be in the waste material.
Where fines having little or no carbon are used, a carbon-bearing carrier material may be used. Suitable materials are coke consisting of coal or lignite or brown coaL or petroleum coke because these cokes, owing to their surface structure and porosity, are particularly suitable to carry the fines on to their surface. However, finely divided or dust form fractions of coal or lignite are also suitable as carrier material, just as are finely divided lightweight fractions from the shredding of plastics. The latter have a tendency to form aggregates similar to flakes and are not injectable in this form.
One criterion for the selection of suitable carrier material is the foaming of the slag. 5 Consequently~ for injection into electric arc furnaces or cupola-type furnaces. carbon-cont~ining carrier materials which exhibit a low proportion of volatile constituents are ~ler~lled. These include lignite coke, anthracite, petrole1lm coke and coke breeze.
For injection into a blast furnace. carbon-co"l~;"illg carrier m~tP.ri~ls having volatile c~ n~titllent~ are best. The amount of volatiles in the total carbon content of the carrier materials should be greater than 8%. T i~nites as well as other low coalified types of coal, wood chippings, plastics chips, or the like can also be used.
For the promotion of the foaming of the slag, the product should have a carbon content between 20 and 40 percent by weight. The carrier materials may be selected and determined by means of pre-analysis.
For the sake of complet~-nec~, it should be est~blish~d that the mixed, reaction and combined products still exhibit amounts of Fe, FeO, Fe203 CaO and CaC03, and the residual hllmi-lity is between S and 15 percent by weight.
The illve~lioll also makes use of the reactivity of the fines. According to the degree of m~-t~ tion~ the fines react with water to form iron oxide, rele~cing heat. When mixing a slurry with the fines iron oxide forms. The heat released during the exothermic reaction causes part of the moisture to evaporate and allows the agglomerates to become crumbly.
For injection the agglomerates must have a density of about 1,2 to about 4 grams per cubic centim~tre. The delivery cross-sections of standard injection devices in the order of between l/2 (about 1 2mm) and 2 inches (about 50mm) made it necessary to sieve the CA 0221~409 1997-09-29 W 096/31630 PCT/~b~"~C-21 products to grain sizes of below about 6 mrn in diameter. Standard injection ~1 ~S~ S
are about 4 to 5 bars for electric arc furnaces and about ~ to 6 bars for blast filrn~c~5 Mixing of dry carrier material and the fines may be carried out both directly and indirectly and in any sequence of steps. For example~ fines and carrier material are first mixed together and then if applicable with water or with a moist carbon-co~ lg slurry; or carbon-cont~ining slurry and carrier material are mixed together first and then mixed with the fines. It is possible to mix fines. carrier material and carbon-cont~ining slurry at the same time.
~valuations injecting agglo",t;l~es consisting of fines, oil-col~ ;llg rolling mill scale slurry, fine coal, petroleum coke or electric furnace filter dust and quick lime or caustic lime into an electric arc furnace have revealed that finer grain fractions of the sieved combined product of below 4 mm in grain size produced a better conversion of the injection product in the molten metal than a grain fraction of under 6 mm in .~i~",~
which is attributed to the larger overall surface area of the smaller grain fraction.
The crumbly agglomerate is readily storable. As soon as it has reacted~ it becomes inert and is suitable for pneumatic conveying. It is possible to inject product into the blast furnace~ electric arc furnace~ converter or cupola-type furnace and even into rotary cement kilns~ (although in this respect it is no longer a metallurgical process in the narrower sense). In principle, it is possible to use slurry of any kind~ that is also metal-cont~ining and mineral-cont~ining slurries but in this respect it must be considered whether, when using metal-cont~ining slurries the alloy arising in the CA 022 1.?409 1997 - 09 - 29 WO 96/31630 PCTI~,.~G;~
metallurgical process still conforrns to the required recipe and whether~ when usmg mineral-co~ illillg slurries the amount of slag resulting does not have a negative effect on the profitability of the steelm~kin~ process. In the simplest case it is therefore also possible to treat the fines with coal slurry~ of the type from washing coal. However such coal slurry has only a low calorific value (because it exhibits a high L)lol~olLion of sterile rnine waste material which only increases the amount of slag of the m~t~ rgical process! but co~ ibules nothing to the foaming of the slag).
Preferably energy-rich slurries are used. such as result. from oil-cont~ining rolling m;ll scale slurry? Fuller's earth or slurries which contain lignite dust or coke dust from coal or lignite or waste m~teri~l slurries from petro~,h~,mictry. Such slurries at the same time reduce the energy required in the subsequent m~t~ rgical process~ because they provide part of the carbon requirement. Although rolling mill scale slurry in particular is regularly interspersed with foreign bodies, as is well known~ such impurities play no role in the present invention~ because the foreign bodies separate from the slurries during tre~tm~,nt of the fines and after the thorough mixing of the components are removed by sieving. This applies also to the lumps or aggregates ~vhich rnay .
occaslonally anse dunng mlxmg.
It is also suitable to use slurries which result from wet dust-extraction of ore reduction plants. The dusts from dry dust-extraction are suitable for a~lmixing to the fines insofar as they do not already themselves form these fines. Also suitable are slurries which result from the wet dust-extraction of blast furnaces~ cupola-type furnaces. electric arc CA 0221~409 1997-09-29 W 096/31630 PCT/GB~G~?-l furnaces, converters. sintering plants and surface tre~tment plants for the grin~ling/and polishing of metals. The corresponding dust from dry dust-extraction may be ~tlmixe to the fines insofar as they do not already themselves form these fines.
In a variation, the additive may include sufficient lime for the lime requirement of the furnace by the addition of substances which exhibit free quicklime, CaO. So according to the invention the amount of slurry necessary to form the reaction product is increased beyond the actual requirement and fly ash is added to the reaction product in addition. The free qllicklime of the fly ash reacts with the residual moisture of the slurry to form calcium hydroxide Ca(OH)2, by which heat is also liberated. The limestone favours the subsequent mP.t~llllrgical process and the liberated heat makes the combined product crumbly.
Preferred is fly ash from the flue gas in the electric filter behind the power station boiler when burning low sulphur fossil fuels. and this includes prim~rily lignite from the Rhine. However, that fly ash which accllmlll~tes during the tre~tmPnt of fuels according to the dry additive process is also suitable if limestone has been added to the fuel to bind the sulphur before combustion. These so-called DAP ashes are usable.
The use of dust or sand from blast furnace top gas is also possible: this accum~ tec when the gas is cleaned from the blast fumace flue. Both stiU contain the residue of non-converted carbon and limestone as well as amounts of iron and iron oxide.
During the ~ ~a~ion of heavy, metal-co"l~;";"g dusts, (and besides those already mentioned this also includes those which result during the grinding of steels), in the first step of the method, by means of mLxing with finely-divided quicklim~ or dolomite the fluidity of the slag is increased in the subsequent m~t~ rgical process. The l,le~ ion of heavy, metal-cont~ining slurries also includes~ besides those already mentioned? grinding slurries for use in the first step of the method. ~y means of the cr~ d use of finely divided fly ash the usually impenetrable slurries are dried at first and thereby made easy to handle. The amount of qllir~lim~ in the fly ash or slag from the ladle furnace assists drying since the free qnicl-lime reacts exothermally with the moisture of the slurry and a considerable part of the moisture inherent in the slurry evaporates thereby; the lime addition which is advantageous for the subsequent mt-t~llnrgical process remains unaffected.
Another waste m~t~ri~l useful in the present invention is made up of di~t;l~;llL forms of ~11"";";l-lll The addition of ~ iS known to be useful in deoxidation and in the fiuxing of slag. Certain forms of ;~ ,;";1"" can attack the lining of a m~t~ rgical vessel, and others are costly. According to this invention waste alll.,,;,,i,l,,, oxide or ;~11"",;";"", metal, e.g. oilywet grinclingc, can be inc~ e~l Such ~ l;lllll m ay also be present in the flyash Where ~1"",;.,;"", is present and the agglomerate has other suitable ingredients, e.g. a high content of iron~ the agglomerates are useful in the cement industry.
W 096131630 PCT/~r~C~21 By means of the sieving in the second stage, a ulliro~ granulation band of under 6 mm in ~ mPter is obtained. At the same time foreign bodies are retained, having been exposed in the first step by the so-called "rolling up" more particularly of the rolling mill scale slurry. These foreign bodies and larger lumps may be ground up if applicable and can be inserted into the method cycle again at a suitable point.
In the third step of the method the sieved off fine fraction co~ ;llg carbon-cont~ining dusts and lime-stone-cont~ining agglomerates is mixed thoroughly with these. This final step contributes substantially lowering the density until they become blowable or injectable under air or other gas ~leS~
In the case of the added carbon-co. ,1 ~ ;. .;. .g dusts the use of lignite coke dust, petroleum coke or anthracite or dusts from slightly or low volatile coal or l~~ s thereof is ~rcr~ d, wherein their respective grain size is below 1 mm in ~i~mPtçr. The addition of carbon is known to promote the foaming of slag in the subsequent metallurgical process. Where the waste material has an organic fraction! e.g. an oiL as in the case of metal-ca,-l;1;..;..g slurries from surface m~c~,hining, such as~ e.g. grin~ling slurries. or in the case of rolling mill scale slurries less carbon dust will be required than for slurries which do not bring with them per se this kind of organic a~l.";~ill"~s~ e.g. with slurries from the wet cleaning of gas from molten metals.
W 096/31630 PcTl~b~ Q?
The addition of carbon-co"li.;";,.~ dusts alone may not be enough to lower the density to the point where the product can be injected pne -m~ti~.~lly. Instead a carrier material in which the mixture consisting of metal-co"l~;";,.g dust~ calcium and carbon can be added may be present in order to reduce its density further. T im~stone-co..l~
agglomerates in sphere form. as they result from the ~ ion of the boiler feed water from steam power stations~ which operate with steam turbines have proved suitable for this purpose. These agglomerates are smalL light, stable spheres of an average diameter of 1 to 2 mr4 which are extremely resistant to compression and abrasion; the grain size ranges from 0.5 to 6 mm. These spheres result from the removal of calcium and iron from the boiler feed water suitable for the steam-driven turbines. In the centre of the spheres there is a tiny quartz grain on which the lime extracted from the boiler feed water and the iron in crystalline form have acc~lm~ te-l The colour of these spheres is beige, they have a smooth surface and exhibit a high co..4,les~ive strength. Normally they are disposed of on the dump.
In the case of the present invention the spheres are suitable preferably as carrier for the mix consisting of heavy metal particles, lime and carbon. Bonding to the carrier is ensured by electrostatic forces as well as the moisture from the water ~ al~Lion.
Their content of silicon~ lime and iron are helpful for the subsequent metallurgical process.
In other aspects the invention provides;
W O96/31630 PcTlGB9rl~~Q2 - a pnellm~tir~lly injectable feed material for use as an additive to the molten metal in an electric arc fur~ace, the m~trri~l comprising the reaction product of a waste particulate material co~ ;"i"g heavy metal elements and oily mill scale, the material being in the form of agglomerates having a particle size from about Omm to about 6mm;
- a pnenm~ir~lly injectable feed material for use as an additive to the molten metal in an electric arc furnace. the material comprising the reaction product of a waste particulate material co"l ~ g heavy metal elçmrnt~ and directly reduced iron fines, the feed material being in the form of agglomerates having a particle size from about Omm to about 6mm;
- either of these feed materials, and including a source of carbon in particulate form: and - either of these feed materials and in which burnt lime was present and particip~tecl in the reaction In order that the invention may be well understood it will now be discussed by way of çx~mple only and with reference to the accompanving dia~rammatic drawings in which:
W 096/31630 PCT/GB9''~ Y?-Figure 1 shows sch~m~tic~lly one process of the invention. and sl Figure 2 is graphs showing exotherrnic reactions.
As shown in Figure 1, a high quality steel slab 2 is rolled into a sheet 3 at a rolling mill.
Water S under ~es~ is added to the rolling process via a nozle 4. The rolling mill scale 6 is collected as rolling mill scale slurry 7 in a trough 8 undemeath the rolling rnill stand 1.
Separately coal 10 is burned in a power station boiler 9. The hot flue gas 11 arising is passed over heat exeh~nger surfaces 12 in which boiler feed water 13 circulates and which is converted into steam 14 on the heat çxch~nger surface 12. The flue gas 11 leaves the boiler via an electric filter 33, where the finely divided fly ash 15 which is carried along and separated from the flue gas before it can be dischalged through the chimney 16 into the atmosphere.
The rolling mill scale slurry 7 and separated fly ash 15 are fed to a first rnixer 17~
wherein the rolling mill scale slurry 7 and the fly ash 15 are intim~tçly mixed. During mixing with the fly ash 15 the moist rolling mill scale slurry 7 dries out to form an agglomerate product having a crumbly con~ictl~nCy. The reaction is exotherrnic and the water evaporates. The first mix 1~ leaving the mixer 17 has a temperature above ~mhiçnt and passed through a sieve 19. where a fine fraction ~0 is sieved off. The CA 0221~409 1997-09-29 W O96/31630 PCT/~ r-~~~21 oversize 21 from the sieve 19 contains the foreign bodies and i"~ iLies present previously in the rolling mill scale slurry 7; these are discarded. The fine fraction 20 having a grain size range of under 1 mm flows to a second mixer 22 where it is mixed with lignite coke dust 23 and lime-c~"l;.;"i"g spherical agglomerates whose average grain size is between O.S and 2 mm.
The spheres 24 have been derived from a filter 25 where the boiler feed water 13 of the power station boiler 9 is prepared for passage to the turbines. After the water vapour 14 has been stress relieved in the steam turbine 34, it flows through a condenser 26, where it condenses again to form boiler feed water 13. The con-l~n~ed boiler feed water 13 is forced by feed water pump through a filter 25. Quartz grains 28 are added to the filter 25, where the lime contained in the boiler feed water 13 and the iron acc~lml-l~te in order to form the spheres 24. Losses of boiler feed water 13 are compensated for by fresh water introduced via the pipe 29.
The agglomerated product 30, consisting of finely divided metals, lime and carbon~
which leaves the second mixer 22 has a dry, powder-like con~ict~ncy with grain sizes between 1 and 6 mm and average specific weight of 2g/cm3 and is injected by blower 32 into a blast furnace 33.
In an evaluation to confirrn that direct reduced iron could be used~ differing amounts of water were added one after the other to a quantity of 1 kg. of ultra-fine sponge iron and then stirred. The reaction of the iron oxide with the water was measured by the temperature increase observed in the process. The measured values are recorded in the Tables I to III and illustrated in the corresponding graphs of Figure 2.
Initial Material: 1 kg ultra-fine sponge iron in a beaker at 20~C.
Addition of 5 per cent by weight of water corresponding to 50 grams.
Time (minutes) Tempe.~lure (~C) ~ 20 The results are also shown in Figure 1 from which it can be seen that the temperature rises by 4~C in the course of 6 mimltes and remains constant therea~er.
II Another 50 grams of water is added to the mix from I and both are stirred by hand for 4 minlltes Time (Minutes) Temperature (~C) 0 ~5 ~ 2 26 W 096/31630 PCT/~b-''O~Q21 6 27.5 lg 32 The results are also shown in the graph. The temperature rises by another 7~C
in the course of 16 misllltes and ~ S constant thereafter.
III Another 50 gra_s of water is added to the mix from ~1 and both stirred by hand for 3 minlltes. The temperature was measured.
Time (Minutes) TemPerature (~C) 2 32.5 6 33.5 2 34.5 35.5 22 35.5 24 35.5 Results are also shown in the graph. The temperature rises slowly by a further 3.5~C in the course of 18 minlltes and remains constant thereafter.
As can be seen therefrom, the most violent reaction starts in mixing phase II and fades gradually in mixing phase III.
The invention relates to a method of use of a wide range of metal Cont~inin~ m~t~ lc which are otherwise used with ~liffi~lllty or just dumped as waste.
One suitable rnaterial is iron ore fine dust. This is difficult to dispose of. During pelletising fine ores having a grain diameter of under about 0.2 rnm are wetted and mixed with binders, e.g. bentonite, to form lu~s. The pellets are subjected to flame hardening or sintering because this is the only way in which such fines can only be used in a subsequent m~t~ lrgical process. This is similar to the l.le~ ion of fines by direct reduction. known as the names of COREX ~ MIDREX ~ or HYL~. For example in the case of the MIDREX~ process the fine ore is acted upon by reduction gases in fllli(1iced bed reactors at te~ c.~Lul~s between 500 and 800~C. The reduction gases contain H2 and CO and also CO2, H2O~ CH4 and N2 . Ple~ ion takes place in a series of fllli~liced bed reactors~ connected in series, in which the degree of reduction increases from reactor to reactor to reach values of mt-t~llic~tion of between 92 and 94% at the exit of the last fluidised bed reactor. The fines reduced in this manner are then hot briquetted in order to obtain the lump form which is necessary for the subsequent metallurgical process. Both during such sintering and during ~,lc~al~ion of the fines. ferrous dusts accumulate~ which are very fine and extremelv reactive. The CA 0221~409 1997-09-29 dusts also contain proportions of non-converted carbon. Such fines cannot be blown or injected into a metallurgical furnace because they have too high a density.
Other heavy metal cu~ ;i.;,.g dusts or slurries are produced as by-products in the m~ntlf~ctnre and processing of high quality steels. By high quality steel is meant a grade of steel which is intP.nclecl generally for heat tre~tm~nt such as hardening and te~ering. High quality steel has a higher purity than quality or basic steel (cf.
Brockhaus. NaturwissPn~.h~ften und Technik (Natural Science and Technology), special edition 1989, volume l, key word). Such steels are produced in electric arc furnaces from steel scrap and alloying conctit~l.o.nt~ The dust contained i~ the smplting gases is very finely divided and has a high specific weight more than 4 grams per cubic cPntimP.tre. The dust is separated in the electric filters installed beyond the electric furnace. It is also usual to wash out the dust from the .cmelting gases using water to produce a heavy metal co-~ g slurry. The scrap charge usually contains zinc which evaporates at the high temperatures in the mPt~llnrgical vessel and is deposited in the flue gas. These dusts (loaded with the heavy metal zinc) from dry dust extraction or slurries in the case of wet dust extraction can only be deposited at special dumps or must be subjected to expensive separation measures.
For the separation ~ ~aLiOn process of this kind of Zn-loaded dusts or slurries it is of great economic advantage if the Zn content is enriched to over ~5% e.g. 40% or more bv recycling.
W 096131630 PCT/GB~"~CQ~1 High quality steel may be treated in a rolling mill. In this case an extremely heavy rolling mill scale slurry results~ which besides the metallic components also contains ul;Lies in lump form from metal parts, orgar~ic material or plastics. Larger pieces of metaL such as screws. and cle~ning rags, cigarette ends and working gloves, yoghurt cartons and plastic bags can also be dumped by mtidy workmen in the rolling mi'il scale slurry.
All metal dusts and slurries arising during the production of basic, quality and high quality steel are finely divided (fine granulometry in the grain size range of a few microns up to 1 mm) and contain alloying metals. These alloying metals include chiefly chromillm, cobalt nickel, lead, m~nganese7 t-mg.ct~n~ ;.. , v~n~ m, zinc and molybdenu~ which are added to the individual grades of steel in differing amounts according to pre-set recipes and together with the iron, are responsible for the heaviness of the dusts and slurries. Although these dusts and slurries contain valuable sllbst~nces it has not been possible to reclaim and re-use these substances to a s~ticfactQry extent because of their inherent fineness and heaviness. In many cases the dusts c~..l~;..;..~ valuable substances are dumped but this is bad for en~ o.... ~-.l~l protection and wasteful.
~ It is one object of this invention to provide a method of recovering the valuable components of a wide variety of waste materials and introducing them in a particularly convenient way into a metallurgical vessel for re-use.
CA 0221~409 1997-09-29 W 096/31630 PCT/~b9C1'~.~21 According to the invention in one aspect there is provided a method of treating a waste f material cont~ining heavy metals. the method comprising mixing the waste material and a relatively less dense particulate material cont~ining metal oxide material and water so as to cause an exothermic reaction and thereby for_ relatively dry agglomerates;
sieving the agglomerates to isolate those having a size in the range of from about Omm to about 6mm; and pneum~ti~lly injecting the isolated agglomerates into a m~t~lhlrgical vessel Co,.l~;..i"g molten metal and under a reducing atmosphere.
The oxide material may be burnt lime or directly reduced iron. Most preferably the agglomerates are injected with carbon (which is required for other purposes in the m~t~ lrgical vessel such as a reduction reaction). The carbon may be provided from a variety of sources and may already be in the waste material.
Where fines having little or no carbon are used, a carbon-bearing carrier material may be used. Suitable materials are coke consisting of coal or lignite or brown coaL or petroleum coke because these cokes, owing to their surface structure and porosity, are particularly suitable to carry the fines on to their surface. However, finely divided or dust form fractions of coal or lignite are also suitable as carrier material, just as are finely divided lightweight fractions from the shredding of plastics. The latter have a tendency to form aggregates similar to flakes and are not injectable in this form.
One criterion for the selection of suitable carrier material is the foaming of the slag. 5 Consequently~ for injection into electric arc furnaces or cupola-type furnaces. carbon-cont~ining carrier materials which exhibit a low proportion of volatile constituents are ~ler~lled. These include lignite coke, anthracite, petrole1lm coke and coke breeze.
For injection into a blast furnace. carbon-co"l~;"illg carrier m~tP.ri~ls having volatile c~ n~titllent~ are best. The amount of volatiles in the total carbon content of the carrier materials should be greater than 8%. T i~nites as well as other low coalified types of coal, wood chippings, plastics chips, or the like can also be used.
For the promotion of the foaming of the slag, the product should have a carbon content between 20 and 40 percent by weight. The carrier materials may be selected and determined by means of pre-analysis.
For the sake of complet~-nec~, it should be est~blish~d that the mixed, reaction and combined products still exhibit amounts of Fe, FeO, Fe203 CaO and CaC03, and the residual hllmi-lity is between S and 15 percent by weight.
The illve~lioll also makes use of the reactivity of the fines. According to the degree of m~-t~ tion~ the fines react with water to form iron oxide, rele~cing heat. When mixing a slurry with the fines iron oxide forms. The heat released during the exothermic reaction causes part of the moisture to evaporate and allows the agglomerates to become crumbly.
For injection the agglomerates must have a density of about 1,2 to about 4 grams per cubic centim~tre. The delivery cross-sections of standard injection devices in the order of between l/2 (about 1 2mm) and 2 inches (about 50mm) made it necessary to sieve the CA 0221~409 1997-09-29 W 096/31630 PCT/~b~"~C-21 products to grain sizes of below about 6 mrn in diameter. Standard injection ~1 ~S~ S
are about 4 to 5 bars for electric arc furnaces and about ~ to 6 bars for blast filrn~c~5 Mixing of dry carrier material and the fines may be carried out both directly and indirectly and in any sequence of steps. For example~ fines and carrier material are first mixed together and then if applicable with water or with a moist carbon-co~ lg slurry; or carbon-cont~ining slurry and carrier material are mixed together first and then mixed with the fines. It is possible to mix fines. carrier material and carbon-cont~ining slurry at the same time.
~valuations injecting agglo",t;l~es consisting of fines, oil-col~ ;llg rolling mill scale slurry, fine coal, petroleum coke or electric furnace filter dust and quick lime or caustic lime into an electric arc furnace have revealed that finer grain fractions of the sieved combined product of below 4 mm in grain size produced a better conversion of the injection product in the molten metal than a grain fraction of under 6 mm in .~i~",~
which is attributed to the larger overall surface area of the smaller grain fraction.
The crumbly agglomerate is readily storable. As soon as it has reacted~ it becomes inert and is suitable for pneumatic conveying. It is possible to inject product into the blast furnace~ electric arc furnace~ converter or cupola-type furnace and even into rotary cement kilns~ (although in this respect it is no longer a metallurgical process in the narrower sense). In principle, it is possible to use slurry of any kind~ that is also metal-cont~ining and mineral-cont~ining slurries but in this respect it must be considered whether, when using metal-cont~ining slurries the alloy arising in the CA 022 1.?409 1997 - 09 - 29 WO 96/31630 PCTI~,.~G;~
metallurgical process still conforrns to the required recipe and whether~ when usmg mineral-co~ illillg slurries the amount of slag resulting does not have a negative effect on the profitability of the steelm~kin~ process. In the simplest case it is therefore also possible to treat the fines with coal slurry~ of the type from washing coal. However such coal slurry has only a low calorific value (because it exhibits a high L)lol~olLion of sterile rnine waste material which only increases the amount of slag of the m~t~ rgical process! but co~ ibules nothing to the foaming of the slag).
Preferably energy-rich slurries are used. such as result. from oil-cont~ining rolling m;ll scale slurry? Fuller's earth or slurries which contain lignite dust or coke dust from coal or lignite or waste m~teri~l slurries from petro~,h~,mictry. Such slurries at the same time reduce the energy required in the subsequent m~t~ rgical process~ because they provide part of the carbon requirement. Although rolling mill scale slurry in particular is regularly interspersed with foreign bodies, as is well known~ such impurities play no role in the present invention~ because the foreign bodies separate from the slurries during tre~tm~,nt of the fines and after the thorough mixing of the components are removed by sieving. This applies also to the lumps or aggregates ~vhich rnay .
occaslonally anse dunng mlxmg.
It is also suitable to use slurries which result from wet dust-extraction of ore reduction plants. The dusts from dry dust-extraction are suitable for a~lmixing to the fines insofar as they do not already themselves form these fines. Also suitable are slurries which result from the wet dust-extraction of blast furnaces~ cupola-type furnaces. electric arc CA 0221~409 1997-09-29 W 096/31630 PCT/GB~G~?-l furnaces, converters. sintering plants and surface tre~tment plants for the grin~ling/and polishing of metals. The corresponding dust from dry dust-extraction may be ~tlmixe to the fines insofar as they do not already themselves form these fines.
In a variation, the additive may include sufficient lime for the lime requirement of the furnace by the addition of substances which exhibit free quicklime, CaO. So according to the invention the amount of slurry necessary to form the reaction product is increased beyond the actual requirement and fly ash is added to the reaction product in addition. The free qllicklime of the fly ash reacts with the residual moisture of the slurry to form calcium hydroxide Ca(OH)2, by which heat is also liberated. The limestone favours the subsequent mP.t~llllrgical process and the liberated heat makes the combined product crumbly.
Preferred is fly ash from the flue gas in the electric filter behind the power station boiler when burning low sulphur fossil fuels. and this includes prim~rily lignite from the Rhine. However, that fly ash which accllmlll~tes during the tre~tmPnt of fuels according to the dry additive process is also suitable if limestone has been added to the fuel to bind the sulphur before combustion. These so-called DAP ashes are usable.
The use of dust or sand from blast furnace top gas is also possible: this accum~ tec when the gas is cleaned from the blast fumace flue. Both stiU contain the residue of non-converted carbon and limestone as well as amounts of iron and iron oxide.
During the ~ ~a~ion of heavy, metal-co"l~;";"g dusts, (and besides those already mentioned this also includes those which result during the grinding of steels), in the first step of the method, by means of mLxing with finely-divided quicklim~ or dolomite the fluidity of the slag is increased in the subsequent m~t~ rgical process. The l,le~ ion of heavy, metal-cont~ining slurries also includes~ besides those already mentioned? grinding slurries for use in the first step of the method. ~y means of the cr~ d use of finely divided fly ash the usually impenetrable slurries are dried at first and thereby made easy to handle. The amount of qllir~lim~ in the fly ash or slag from the ladle furnace assists drying since the free qnicl-lime reacts exothermally with the moisture of the slurry and a considerable part of the moisture inherent in the slurry evaporates thereby; the lime addition which is advantageous for the subsequent mt-t~llnrgical process remains unaffected.
Another waste m~t~ri~l useful in the present invention is made up of di~t;l~;llL forms of ~11"";";l-lll The addition of ~ iS known to be useful in deoxidation and in the fiuxing of slag. Certain forms of ;~ ,;";1"" can attack the lining of a m~t~ rgical vessel, and others are costly. According to this invention waste alll.,,;,,i,l,,, oxide or ;~11"",;";"", metal, e.g. oilywet grinclingc, can be inc~ e~l Such ~ l;lllll m ay also be present in the flyash Where ~1"",;.,;"", is present and the agglomerate has other suitable ingredients, e.g. a high content of iron~ the agglomerates are useful in the cement industry.
W 096131630 PCT/~r~C~21 By means of the sieving in the second stage, a ulliro~ granulation band of under 6 mm in ~ mPter is obtained. At the same time foreign bodies are retained, having been exposed in the first step by the so-called "rolling up" more particularly of the rolling mill scale slurry. These foreign bodies and larger lumps may be ground up if applicable and can be inserted into the method cycle again at a suitable point.
In the third step of the method the sieved off fine fraction co~ ;llg carbon-cont~ining dusts and lime-stone-cont~ining agglomerates is mixed thoroughly with these. This final step contributes substantially lowering the density until they become blowable or injectable under air or other gas ~leS~
In the case of the added carbon-co. ,1 ~ ;. .;. .g dusts the use of lignite coke dust, petroleum coke or anthracite or dusts from slightly or low volatile coal or l~~ s thereof is ~rcr~ d, wherein their respective grain size is below 1 mm in ~i~mPtçr. The addition of carbon is known to promote the foaming of slag in the subsequent metallurgical process. Where the waste material has an organic fraction! e.g. an oiL as in the case of metal-ca,-l;1;..;..g slurries from surface m~c~,hining, such as~ e.g. grin~ling slurries. or in the case of rolling mill scale slurries less carbon dust will be required than for slurries which do not bring with them per se this kind of organic a~l.";~ill"~s~ e.g. with slurries from the wet cleaning of gas from molten metals.
W 096/31630 PcTl~b~ Q?
The addition of carbon-co"li.;";,.~ dusts alone may not be enough to lower the density to the point where the product can be injected pne -m~ti~.~lly. Instead a carrier material in which the mixture consisting of metal-co"l~;";,.g dust~ calcium and carbon can be added may be present in order to reduce its density further. T im~stone-co..l~
agglomerates in sphere form. as they result from the ~ ion of the boiler feed water from steam power stations~ which operate with steam turbines have proved suitable for this purpose. These agglomerates are smalL light, stable spheres of an average diameter of 1 to 2 mr4 which are extremely resistant to compression and abrasion; the grain size ranges from 0.5 to 6 mm. These spheres result from the removal of calcium and iron from the boiler feed water suitable for the steam-driven turbines. In the centre of the spheres there is a tiny quartz grain on which the lime extracted from the boiler feed water and the iron in crystalline form have acc~lm~ te-l The colour of these spheres is beige, they have a smooth surface and exhibit a high co..4,les~ive strength. Normally they are disposed of on the dump.
In the case of the present invention the spheres are suitable preferably as carrier for the mix consisting of heavy metal particles, lime and carbon. Bonding to the carrier is ensured by electrostatic forces as well as the moisture from the water ~ al~Lion.
Their content of silicon~ lime and iron are helpful for the subsequent metallurgical process.
In other aspects the invention provides;
W O96/31630 PcTlGB9rl~~Q2 - a pnellm~tir~lly injectable feed material for use as an additive to the molten metal in an electric arc fur~ace, the m~trri~l comprising the reaction product of a waste particulate material co~ ;"i"g heavy metal elements and oily mill scale, the material being in the form of agglomerates having a particle size from about Omm to about 6mm;
- a pnenm~ir~lly injectable feed material for use as an additive to the molten metal in an electric arc furnace. the material comprising the reaction product of a waste particulate material co"l ~ g heavy metal elçmrnt~ and directly reduced iron fines, the feed material being in the form of agglomerates having a particle size from about Omm to about 6mm;
- either of these feed materials, and including a source of carbon in particulate form: and - either of these feed materials and in which burnt lime was present and particip~tecl in the reaction In order that the invention may be well understood it will now be discussed by way of çx~mple only and with reference to the accompanving dia~rammatic drawings in which:
W 096/31630 PCT/GB9''~ Y?-Figure 1 shows sch~m~tic~lly one process of the invention. and sl Figure 2 is graphs showing exotherrnic reactions.
As shown in Figure 1, a high quality steel slab 2 is rolled into a sheet 3 at a rolling mill.
Water S under ~es~ is added to the rolling process via a nozle 4. The rolling mill scale 6 is collected as rolling mill scale slurry 7 in a trough 8 undemeath the rolling rnill stand 1.
Separately coal 10 is burned in a power station boiler 9. The hot flue gas 11 arising is passed over heat exeh~nger surfaces 12 in which boiler feed water 13 circulates and which is converted into steam 14 on the heat çxch~nger surface 12. The flue gas 11 leaves the boiler via an electric filter 33, where the finely divided fly ash 15 which is carried along and separated from the flue gas before it can be dischalged through the chimney 16 into the atmosphere.
The rolling mill scale slurry 7 and separated fly ash 15 are fed to a first rnixer 17~
wherein the rolling mill scale slurry 7 and the fly ash 15 are intim~tçly mixed. During mixing with the fly ash 15 the moist rolling mill scale slurry 7 dries out to form an agglomerate product having a crumbly con~ictl~nCy. The reaction is exotherrnic and the water evaporates. The first mix 1~ leaving the mixer 17 has a temperature above ~mhiçnt and passed through a sieve 19. where a fine fraction ~0 is sieved off. The CA 0221~409 1997-09-29 W O96/31630 PCT/~ r-~~~21 oversize 21 from the sieve 19 contains the foreign bodies and i"~ iLies present previously in the rolling mill scale slurry 7; these are discarded. The fine fraction 20 having a grain size range of under 1 mm flows to a second mixer 22 where it is mixed with lignite coke dust 23 and lime-c~"l;.;"i"g spherical agglomerates whose average grain size is between O.S and 2 mm.
The spheres 24 have been derived from a filter 25 where the boiler feed water 13 of the power station boiler 9 is prepared for passage to the turbines. After the water vapour 14 has been stress relieved in the steam turbine 34, it flows through a condenser 26, where it condenses again to form boiler feed water 13. The con-l~n~ed boiler feed water 13 is forced by feed water pump through a filter 25. Quartz grains 28 are added to the filter 25, where the lime contained in the boiler feed water 13 and the iron acc~lml-l~te in order to form the spheres 24. Losses of boiler feed water 13 are compensated for by fresh water introduced via the pipe 29.
The agglomerated product 30, consisting of finely divided metals, lime and carbon~
which leaves the second mixer 22 has a dry, powder-like con~ict~ncy with grain sizes between 1 and 6 mm and average specific weight of 2g/cm3 and is injected by blower 32 into a blast furnace 33.
In an evaluation to confirrn that direct reduced iron could be used~ differing amounts of water were added one after the other to a quantity of 1 kg. of ultra-fine sponge iron and then stirred. The reaction of the iron oxide with the water was measured by the temperature increase observed in the process. The measured values are recorded in the Tables I to III and illustrated in the corresponding graphs of Figure 2.
Initial Material: 1 kg ultra-fine sponge iron in a beaker at 20~C.
Addition of 5 per cent by weight of water corresponding to 50 grams.
Time (minutes) Tempe.~lure (~C) ~ 20 The results are also shown in Figure 1 from which it can be seen that the temperature rises by 4~C in the course of 6 mimltes and remains constant therea~er.
II Another 50 grams of water is added to the mix from I and both are stirred by hand for 4 minlltes Time (Minutes) Temperature (~C) 0 ~5 ~ 2 26 W 096/31630 PCT/~b-''O~Q21 6 27.5 lg 32 The results are also shown in the graph. The temperature rises by another 7~C
in the course of 16 misllltes and ~ S constant thereafter.
III Another 50 gra_s of water is added to the mix from ~1 and both stirred by hand for 3 minlltes. The temperature was measured.
Time (Minutes) TemPerature (~C) 2 32.5 6 33.5 2 34.5 35.5 22 35.5 24 35.5 Results are also shown in the graph. The temperature rises slowly by a further 3.5~C in the course of 18 minlltes and remains constant thereafter.
As can be seen therefrom, the most violent reaction starts in mixing phase II and fades gradually in mixing phase III.
Claims (22)
1. A method of treating a waste material containing heavy metal metals, the method comprising mixing the waste material and a relatively less dense particulate material containing oxide metal and water so as to cause an exothermic reaction and thereby form relatively dry agglomerates; sieving the agglomerates to isolate those having a size in the range of from about 0 mm to about 6mm; and pneumatically injecting the isolated agglomerates into a metallurgical vessel containing molten metal and under a reducing atmosphere.
2. A method according to Claim 1, wherein the oxide material is burnt lime.
3. A method according to Claim 1, wherein the oxide material is directly reduced iron.
4. A method according to Claim 1, 2 or 3, wherein the waste material is a dust obtained from an electric arc furnace.
5. A method according to any of Claims 1, 2 or 3, wherein a source of aluminium is present.
6. A method for preparing fines for use in a subsequent metallurgical process, the fines being from at least partly reduced iron ore in dust form, comprising mixing the fines with a fine-grained carrier material having a low density to produce crumbly product results and sieving the product to provide material between 0 and 6 mm grain size suitable for injection in the metallurgical process.
7. A method according to Claim 6, wherein the carrier material used is a carbon-containing material.
8. A method according to Claim 6 or 7, wherein sufficient water is added to improve the adhesion between the fines and the carrier material.
9. A method according to Claim 6, 7 or 8, wherein by adding a slurry of water and carbon to the mixed product and mixing thoroughly.
10. A method according to Claim 9, wherein an excess of slurry is used together with a substance in dust form to finely divided form, containing free quick lime.
11. A method according to Claim 9 or 10, wherein the slurry is an oil-containing rolling mill scale slurry or one from the machining of steel or metals suitable for alloying steel by means of oil-containing cutting fluids.
12. A method according to Claim 9. wherein the slurry is from treating blast furnace gas with water.
13. A method according to Claim 10, wherein the slurry contains fly ash from the combustion of fossil fuels which contain calcium.
14. A method according to Claim 13, wherein the slurry contains fly ash which result from the cleaning of flue gases by means of limestone or calcium hydroxide at a power station boiler.
15. A method according to Claim 14, wherein the slurry contains blast furnace flue dust.
16. A method according to one of Claims 9 to 15, wherein an injectable fine fraction is sieved off from the reaction or combined product and an oversize comminuted for reprocessing.
17. A pneumatically injectable feed material for use as an additive to the molten metal in an electric arc furnace, the material comprising the reaction product of a waste particulate material containing heavy metal elements and oily mill scale, the material being in the form of agglomerates having a particle size from about 0mm to about 6mm.
18. A pneumatic injectable feed material for use as an additive to the molten metal in an electric arc furnace, the material comprising the reaction product of a waste particulate material containing heavy metal elements and directly reduced iron fines. the feed material being in the form of agglomerates having a particle size from about 0mm to about 6mm.
19. A feed material according to Claim 17 or 18, including a source of carbon in particulate form.
20. A feed material according to Claim 19, wherein the content of carbon source is sufficient to reduce the content of iron oxide in the feed material.
21. A feed material according to any of Claims 17 to 20, wherein burnt limes was present and participated in the reaction.
22. A feed material according to any of Claim 17 to 21, also containing aluminium
Applications Claiming Priority (6)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE19512560.0 | 1995-04-04 | ||
DE1995112560 DE19512560A1 (en) | 1995-04-04 | 1995-04-04 | Converting metal-contg. heavy dust or sludge into form suitable for blowing into a metallurgical furnace |
DE19526687.0 | 1995-07-21 | ||
DE1995126687 DE19526687A1 (en) | 1995-04-04 | 1995-07-21 | Process for the preparation of metal-containing dusts or sludges for blowing into a metallurgical process |
DE19537283A DE19537283A1 (en) | 1995-10-06 | 1995-10-06 | Treating waste contg. metallurgical fines to recover metals |
DE19537283.0 | 1995-10-06 |
Publications (1)
Publication Number | Publication Date |
---|---|
CA2215409A1 true CA2215409A1 (en) | 1996-10-10 |
Family
ID=27215015
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
CA 2215409 Abandoned CA2215409A1 (en) | 1995-04-04 | 1996-04-03 | Reuse of metallurgical fines |
Country Status (6)
Country | Link |
---|---|
EP (1) | EP0820531A1 (en) |
JP (1) | JPH11503201A (en) |
AU (1) | AU719637B2 (en) |
BR (1) | BR9604790A (en) |
CA (1) | CA2215409A1 (en) |
WO (1) | WO1996031630A1 (en) |
Families Citing this family (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB2324081A (en) * | 1997-04-07 | 1998-10-14 | Heckett Multiserv Plc | Additives for Electric Arc Furnace |
DE19753389A1 (en) * | 1997-12-02 | 1999-06-24 | Code Gmbh Commercial Developme | Process for processing a reactive mixture of waste materials |
GB2337257B (en) * | 1998-05-11 | 2001-12-12 | Heckett Multiserv Plc | Making injectable additives for furnaces |
JP2008163412A (en) * | 2006-12-28 | 2008-07-17 | Jtekt Corp | Ferrous powder material, its production method, and briquette for raw material for steel making |
Family Cites Families (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS5245518A (en) * | 1975-10-08 | 1977-04-11 | Chikara Hidaka | Production process of pellets using iron ore dust generated from raw m aterial for iron manufacture as raw material |
US4119455A (en) * | 1977-09-28 | 1978-10-10 | Carad, Inc. | Method of recovering iron-bearing by-product flue dust |
DE3727576C1 (en) * | 1987-08-19 | 1988-09-15 | Heinz Staschel | Process for reprocessing fine-grained ferrous by-products from steelworks and metallurgical works to form lumpy material for use in blast furnaces |
DE4200533A1 (en) * | 1991-01-24 | 1992-07-30 | Rheinische Braunkohlenw Ag | METHOD FOR TREATING WASTE |
DE4324343C2 (en) * | 1993-07-20 | 1996-09-12 | Koeppern & Co Kg Maschf | Process for producing briquettes from metallurgical residues |
-
1996
- 1996-04-03 BR BR9604790A patent/BR9604790A/en not_active IP Right Cessation
- 1996-04-03 JP JP53009696A patent/JPH11503201A/en active Pending
- 1996-04-03 CA CA 2215409 patent/CA2215409A1/en not_active Abandoned
- 1996-04-03 AU AU51599/96A patent/AU719637B2/en not_active Ceased
- 1996-04-03 EP EP19960908291 patent/EP0820531A1/en not_active Ceased
- 1996-04-03 WO PCT/GB1996/000821 patent/WO1996031630A1/en not_active Application Discontinuation
Also Published As
Publication number | Publication date |
---|---|
AU719637B2 (en) | 2000-05-11 |
EP0820531A1 (en) | 1998-01-28 |
AU5159996A (en) | 1996-10-23 |
MX9707653A (en) | 1998-08-30 |
JPH11503201A (en) | 1999-03-23 |
WO1996031630A1 (en) | 1996-10-10 |
BR9604790A (en) | 1998-07-07 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US5807420A (en) | Process for reduction of iron with solid fuel objects as amended by exam | |
US4116679A (en) | Metallized iron briquet | |
US5885328A (en) | Method of agglomerating oil-containing steel mill waste | |
US6342089B1 (en) | Direct reduced iron pellets | |
US3313617A (en) | Iron-containing flux material for steel-making process | |
CN1328358C (en) | Coal briquettes for smelting reduction process, and method for manufacturing the same | |
EP1579016B1 (en) | Cold briquetting and pelletisation of mineral fines using an iron-bearing hydraulic binder | |
US9011573B2 (en) | Process for recycling of steel industry iron bearing by-products, pellet obtained in that process and use thereof | |
CN1067439C (en) | Treatment method for high zinc containing iron dust | |
CA2444158A1 (en) | Method for producing feed material for molten metal production and method for producing molten metal | |
CA2122529A1 (en) | Process for utilising iron-containing wastes or residues | |
US6921427B2 (en) | Process for cold briquetting and pelletization of ferrous or non-ferrous ores or mineral fines by iron bearing hydraulic mineral binder | |
Agrawal et al. | Productive recycling of basic oxygen furnace sludge in integrated steel plant | |
EP1772527B1 (en) | Method for production of an addition briqutte | |
US4063930A (en) | Preparation of weatherable ferrite agglomerate | |
AU719637B2 (en) | Reuse of metallurgical fines | |
CA2309606A1 (en) | Method for producing directly-reduced iron, liquid pig iron and steel | |
Sikora et al. | The anthracite as sinter fuels | |
WO1997017307A2 (en) | Method for preparing hardened granules from a particulate material | |
JPH06330198A (en) | Method for recovering zinc in dust | |
CN107557532A (en) | Method for treating metallurgical dust removal ash | |
CZ297694B6 (en) | Ingredient scrap briquette and process for producing thereof | |
GB1572566A (en) | Process for producing reduced iron pellets from iron-containing dust | |
RU2281976C2 (en) | Burden for production of agglomerate | |
Singh et al. | Cold bond agglomerates of iron and steel plant byproducts as burden material for blast furnaces |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
FZDE | Discontinued |