EP0946449A1 - Method for the insolubilisation and consolidation of used brasques from hall-heroult electrolyte vessels - Google Patents
Method for the insolubilisation and consolidation of used brasques from hall-heroult electrolyte vesselsInfo
- Publication number
- EP0946449A1 EP0946449A1 EP97947133A EP97947133A EP0946449A1 EP 0946449 A1 EP0946449 A1 EP 0946449A1 EP 97947133 A EP97947133 A EP 97947133A EP 97947133 A EP97947133 A EP 97947133A EP 0946449 A1 EP0946449 A1 EP 0946449A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- pellets
- additive
- cooking
- mixture
- consolidation
- 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.)
- Withdrawn
Links
- 238000000034 method Methods 0.000 title claims abstract description 42
- 238000007596 consolidation process Methods 0.000 title claims abstract description 18
- 239000003792 electrolyte Substances 0.000 title abstract 2
- 239000000203 mixture Substances 0.000 claims abstract description 47
- 239000008188 pellet Substances 0.000 claims abstract description 43
- 239000000654 additive Substances 0.000 claims abstract description 39
- 150000001875 compounds Chemical class 0.000 claims abstract description 24
- 230000000996 additive effect Effects 0.000 claims abstract description 22
- 239000004568 cement Substances 0.000 claims abstract description 15
- 229910052782 aluminium Inorganic materials 0.000 claims abstract description 9
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims abstract description 9
- 235000012255 calcium oxide Nutrition 0.000 claims abstract description 6
- 238000000227 grinding Methods 0.000 claims abstract description 6
- 239000004570 mortar (masonry) Substances 0.000 claims abstract description 5
- 238000002156 mixing Methods 0.000 claims abstract description 4
- BRPQOXSCLDDYGP-UHFFFAOYSA-N calcium oxide Chemical class [O-2].[Ca+2] BRPQOXSCLDDYGP-UHFFFAOYSA-N 0.000 claims abstract description 3
- 150000003839 salts Chemical class 0.000 claims abstract description 3
- 238000010411 cooking Methods 0.000 claims description 37
- 239000011734 sodium Substances 0.000 claims description 26
- 229910052708 sodium Inorganic materials 0.000 claims description 18
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 claims description 15
- 150000002825 nitriles Chemical class 0.000 claims description 11
- 238000005054 agglomeration Methods 0.000 claims description 10
- 230000002776 aggregation Effects 0.000 claims description 10
- 238000010438 heat treatment Methods 0.000 claims description 9
- 238000007493 shaping process Methods 0.000 claims description 9
- 239000010433 feldspar Substances 0.000 claims description 8
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 7
- 229910052799 carbon Inorganic materials 0.000 claims description 7
- 239000004927 clay Substances 0.000 claims description 7
- 238000004519 manufacturing process Methods 0.000 claims description 7
- 239000002245 particle Substances 0.000 claims description 7
- 239000000843 powder Substances 0.000 claims description 7
- 229910052783 alkali metal Inorganic materials 0.000 claims description 5
- 150000001340 alkali metals Chemical class 0.000 claims description 5
- 230000004927 fusion Effects 0.000 claims description 4
- 238000005469 granulation Methods 0.000 claims description 4
- 230000003179 granulation Effects 0.000 claims description 4
- 238000005470 impregnation Methods 0.000 claims description 4
- 239000011872 intimate mixture Substances 0.000 claims description 4
- -1 CaF2 Chemical class 0.000 claims description 3
- 239000011398 Portland cement Substances 0.000 claims description 3
- 235000019738 Limestone Nutrition 0.000 claims description 2
- 238000007906 compression Methods 0.000 claims description 2
- 230000006835 compression Effects 0.000 claims description 2
- 238000001125 extrusion Methods 0.000 claims description 2
- 239000000446 fuel Substances 0.000 claims description 2
- 239000006028 limestone Substances 0.000 claims description 2
- WUKWITHWXAAZEY-UHFFFAOYSA-L calcium difluoride Chemical compound [F-].[F-].[Ca+2] WUKWITHWXAAZEY-UHFFFAOYSA-L 0.000 claims 1
- 229910001634 calcium fluoride Inorganic materials 0.000 claims 1
- 159000000007 calcium salts Chemical class 0.000 claims 1
- 229910052731 fluorine Inorganic materials 0.000 abstract description 22
- 239000011737 fluorine Substances 0.000 abstract description 19
- YCKRFDGAMUMZLT-UHFFFAOYSA-N Fluorine atom Chemical compound [F] YCKRFDGAMUMZLT-UHFFFAOYSA-N 0.000 abstract description 18
- 235000012211 aluminium silicate Nutrition 0.000 abstract description 11
- 229910052751 metal Inorganic materials 0.000 abstract description 5
- 239000002184 metal Substances 0.000 abstract description 5
- 150000002739 metals Chemical class 0.000 abstract description 4
- 235000008733 Citrus aurantifolia Nutrition 0.000 abstract description 3
- 235000011941 Tilia x europaea Nutrition 0.000 abstract description 3
- 239000004571 lime Substances 0.000 abstract description 3
- 239000004411 aluminium Substances 0.000 abstract 1
- 229910000323 aluminium silicate Inorganic materials 0.000 abstract 1
- 238000009738 saturating Methods 0.000 abstract 1
- 239000012134 supernatant fraction Substances 0.000 abstract 1
- 238000002386 leaching Methods 0.000 description 14
- NLYAJNPCOHFWQQ-UHFFFAOYSA-N kaolin Chemical compound O.O.O=[Al]O[Si](=O)O[Si](=O)O[Al]=O NLYAJNPCOHFWQQ-UHFFFAOYSA-N 0.000 description 12
- 239000005995 Aluminium silicate Substances 0.000 description 10
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 9
- 239000012633 leachable Substances 0.000 description 9
- 239000000047 product Substances 0.000 description 8
- 238000005868 electrolysis reaction Methods 0.000 description 6
- PUZPDOWCWNUUKD-UHFFFAOYSA-M sodium fluoride Chemical compound [F-].[Na+] PUZPDOWCWNUUKD-UHFFFAOYSA-M 0.000 description 6
- 230000015572 biosynthetic process Effects 0.000 description 5
- 229910004261 CaF 2 Inorganic materials 0.000 description 4
- VTYYLEPIZMXCLO-UHFFFAOYSA-L Calcium carbonate Chemical compound [Ca+2].[O-]C([O-])=O VTYYLEPIZMXCLO-UHFFFAOYSA-L 0.000 description 4
- 238000005219 brazing Methods 0.000 description 4
- 239000000428 dust Substances 0.000 description 4
- 239000007789 gas Substances 0.000 description 4
- 239000000377 silicon dioxide Substances 0.000 description 4
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 3
- 238000006243 chemical reaction Methods 0.000 description 3
- 238000002485 combustion reaction Methods 0.000 description 3
- 239000000470 constituent Substances 0.000 description 3
- 238000010494 dissociation reaction Methods 0.000 description 3
- 230000005593 dissociations Effects 0.000 description 3
- 150000002222 fluorine compounds Chemical class 0.000 description 3
- 230000000135 prohibitive effect Effects 0.000 description 3
- 239000011819 refractory material Substances 0.000 description 3
- 235000013024 sodium fluoride Nutrition 0.000 description 3
- 239000011775 sodium fluoride Substances 0.000 description 3
- 238000007711 solidification Methods 0.000 description 3
- 230000008023 solidification Effects 0.000 description 3
- 238000003860 storage Methods 0.000 description 3
- XFXPMWWXUTWYJX-UHFFFAOYSA-N Cyanide Chemical group N#[C-] XFXPMWWXUTWYJX-UHFFFAOYSA-N 0.000 description 2
- KRHYYFGTRYWZRS-UHFFFAOYSA-M Fluoride anion Chemical compound [F-] KRHYYFGTRYWZRS-UHFFFAOYSA-M 0.000 description 2
- PMZURENOXWZQFD-UHFFFAOYSA-L Sodium Sulfate Chemical compound [Na+].[Na+].[O-]S([O-])(=O)=O PMZURENOXWZQFD-UHFFFAOYSA-L 0.000 description 2
- 229910000831 Steel Inorganic materials 0.000 description 2
- 229910000019 calcium carbonate Inorganic materials 0.000 description 2
- 239000000292 calcium oxide Substances 0.000 description 2
- 239000003575 carbonaceous material Substances 0.000 description 2
- 239000003795 chemical substances by application Substances 0.000 description 2
- 238000009472 formulation Methods 0.000 description 2
- 239000010440 gypsum Substances 0.000 description 2
- 229910052602 gypsum Inorganic materials 0.000 description 2
- 239000012212 insulator Substances 0.000 description 2
- 229910052622 kaolinite Inorganic materials 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 238000005507 spraying Methods 0.000 description 2
- 239000010959 steel Substances 0.000 description 2
- BPQQTUXANYXVAA-UHFFFAOYSA-N Orthosilicate Chemical compound [O-][Si]([O-])([O-])[O-] BPQQTUXANYXVAA-UHFFFAOYSA-N 0.000 description 1
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 1
- FZVXUPLDQNBUQZ-UHFFFAOYSA-N [Ca+2].[Ca+2].[Ca+2].[O-][Si]([O-])([O-])O[Si]([O-])([O-])[O-] Chemical compound [Ca+2].[Ca+2].[Ca+2].[O-][Si]([O-])([O-])O[Si]([O-])([O-])[O-] FZVXUPLDQNBUQZ-UHFFFAOYSA-N 0.000 description 1
- BFRXZIMAUMUZJH-UHFFFAOYSA-M [OH-].[Na+].[Na+].[Na+].[Na+].[Al+3].[Al+3].[Al+3].[O-][Si]([O-])([O-])[O-].[O-][Si]([O-])([O-])[O-].[O-][Si]([O-])([O-])[O-] Chemical compound [OH-].[Na+].[Na+].[Na+].[Na+].[Al+3].[Al+3].[Al+3].[O-][Si]([O-])([O-])[O-].[O-][Si]([O-])([O-])[O-].[O-][Si]([O-])([O-])[O-] BFRXZIMAUMUZJH-UHFFFAOYSA-M 0.000 description 1
- 229910052656 albite Inorganic materials 0.000 description 1
- 150000001450 anions Chemical class 0.000 description 1
- 239000002585 base 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
- 230000000903 blocking effect Effects 0.000 description 1
- 238000001354 calcination Methods 0.000 description 1
- 239000000920 calcium hydroxide Substances 0.000 description 1
- 235000011116 calcium hydroxide Nutrition 0.000 description 1
- 230000015556 catabolic process Effects 0.000 description 1
- 238000012824 chemical production Methods 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 238000000354 decomposition reaction Methods 0.000 description 1
- 238000006731 degradation reaction Methods 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 238000006073 displacement reaction Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000008030 elimination Effects 0.000 description 1
- 238000003379 elimination reaction Methods 0.000 description 1
- 230000005496 eutectics Effects 0.000 description 1
- 239000000945 filler Substances 0.000 description 1
- 239000012467 final product Substances 0.000 description 1
- 239000010419 fine particle Substances 0.000 description 1
- 238000010304 firing Methods 0.000 description 1
- 238000005243 fluidization Methods 0.000 description 1
- 125000001153 fluoro group Chemical group F* 0.000 description 1
- 235000011389 fruit/vegetable juice Nutrition 0.000 description 1
- 239000008187 granular material Substances 0.000 description 1
- 238000011068 loading method Methods 0.000 description 1
- 231100000252 nontoxic Toxicity 0.000 description 1
- 230000003000 nontoxic effect Effects 0.000 description 1
- 230000001590 oxidative effect Effects 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 230000001737 promoting effect Effects 0.000 description 1
- 238000005070 sampling Methods 0.000 description 1
- 230000035939 shock Effects 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- 239000010703 silicon Substances 0.000 description 1
- 229910052938 sodium sulfate Inorganic materials 0.000 description 1
- 235000011152 sodium sulphate Nutrition 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 238000004901 spalling Methods 0.000 description 1
- 230000003068 static effect Effects 0.000 description 1
- 238000007669 thermal treatment Methods 0.000 description 1
- 230000009466 transformation Effects 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- A—HUMAN NECESSITIES
- A62—LIFE-SAVING; FIRE-FIGHTING
- A62D—CHEMICAL MEANS FOR EXTINGUISHING FIRES OR FOR COMBATING OR PROTECTING AGAINST HARMFUL CHEMICAL AGENTS; CHEMICAL MATERIALS FOR USE IN BREATHING APPARATUS
- A62D3/00—Processes for making harmful chemical substances harmless or less harmful, by effecting a chemical change in the substances
- A62D3/30—Processes for making harmful chemical substances harmless or less harmful, by effecting a chemical change in the substances by reacting with chemical agents
- A62D3/33—Processes for making harmful chemical substances harmless or less harmful, by effecting a chemical change in the substances by reacting with chemical agents by chemical fixing the harmful substance, e.g. by chelation or complexation
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B18/00—Use of agglomerated or waste materials or refuse as fillers for mortars, concrete or artificial stone; Treatment of agglomerated or waste materials or refuse, specially adapted to enhance their filling properties in mortars, concrete or artificial stone
- C04B18/02—Agglomerated materials, e.g. artificial aggregates
- C04B18/023—Fired or melted materials
-
- A—HUMAN NECESSITIES
- A62—LIFE-SAVING; FIRE-FIGHTING
- A62D—CHEMICAL MEANS FOR EXTINGUISHING FIRES OR FOR COMBATING OR PROTECTING AGAINST HARMFUL CHEMICAL AGENTS; CHEMICAL MATERIALS FOR USE IN BREATHING APPARATUS
- A62D2101/00—Harmful chemical substances made harmless, or less harmful, by effecting chemical change
- A62D2101/40—Inorganic substances
-
- A—HUMAN NECESSITIES
- A62—LIFE-SAVING; FIRE-FIGHTING
- A62D—CHEMICAL MEANS FOR EXTINGUISHING FIRES OR FOR COMBATING OR PROTECTING AGAINST HARMFUL CHEMICAL AGENTS; CHEMICAL MATERIALS FOR USE IN BREATHING APPARATUS
- A62D2101/00—Harmful chemical substances made harmless, or less harmful, by effecting chemical change
- A62D2101/40—Inorganic substances
- A62D2101/45—Inorganic substances containing nitrogen or phosphorus
-
- A—HUMAN NECESSITIES
- A62—LIFE-SAVING; FIRE-FIGHTING
- A62D—CHEMICAL MEANS FOR EXTINGUISHING FIRES OR FOR COMBATING OR PROTECTING AGAINST HARMFUL CHEMICAL AGENTS; CHEMICAL MATERIALS FOR USE IN BREATHING APPARATUS
- A62D2101/00—Harmful chemical substances made harmless, or less harmful, by effecting chemical change
- A62D2101/40—Inorganic substances
- A62D2101/49—Inorganic substances containing halogen
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
- Y02W30/00—Technologies for solid waste management
- Y02W30/50—Reuse, recycling or recovery technologies
- Y02W30/91—Use of waste materials as fillers for mortars or concrete
Definitions
- the invention relates to a process of insolubilization and consolidation in the form of spent pot lining pellets originating from the dismantling of aluminum production tanks by igneous electrolysis according to the Hall-Héroult technique.
- These spent pot liners are formed by the carbonaceous cathode blocks, the seals and the side linings based on carbonaceous materials but also by all of the refractory and aluminous or silico-aluminous insulators arranged on the lateral walls and the bottom of the metal box forming the electrolysis tank.
- these pot liners are heavily impregnated with harmful products, such as soluble sodium or sodo-aluminous fluorides and cyanides, which must be insolubilized or destroyed before landfill or possible reuse.
- thermal treatment methods generally operating in a fluidized bed and based either on a pyrohydrolysis at more than 1000 ° C. of the spent linings according to US 4065551 Elkem, or US 41 13832 and US 41 16809 Kaiser, or on a simple combustion. in the air or in an oxidizing atmosphere of carbon elements, at a temperature of about 800 ° C, sufficient to decompose cyanides without causing significant release of volatile fluorinated compounds, according to US 4053375 Reynolds or according to the article by LC Blayden and SG Epstein, Journal of Metals, July 1984 page 24.
- the methods and devices using the thermal route are limited in their possibilities by the nature and the composition of the pot linings to be treated.
- the pot lining particles due to the fusion of certain eutectic compounds formed during combustion, the pot lining particles have a strong tendency to agglomerate. It becomes impossible to avoid their solidification and consequently to maintain a fluidized bed and a fortiori a dense bed if the combustion is carried out for example in a rotating oven with a long residence time.
- this process must be completed at the end of the heat treatment carried out at a temperature sufficient to decompose the cyanides, by a final operation of insolubilization of the soluble residual fluorides consisting in spraying milk of lime on the pulverulent mixture leaving the oven. heat treatment.
- this additional operation carried out in a semi-humid environment complicates and increases the cost of the process, the final product thus obtained is difficult to store or handle in the state given the presence of dust and fine particles.
- US 52451 15 EP 0465388B
- US 5365012 EP 0465388B
- Aluminum Pechiney recommend the introduction of a single additive based on lime and preferably gypsum, mixed with the finely ground pot lining to insolubilize the fluorinated compounds in the state of CaF 2 after a heat treatment carried out at a temperature sufficient to decompose the cyanides but of a very short duration to avoid the bonding phenomena.
- the pulverulent mixture is injected under gas pressure at the top of a cyclonic reactor to be recovered at its base in the form of inert pulverulent residue.
- the method according to the invention satisfies this triple condition. It is based on the observation that by adding appropriate additives to the old crushed pot lining, it is possible to effectively insolubilize not only the fluorine of the fluorinated impregnation compounds but also the alkali metals such as sodium, and this while promoting contrary to the usual practices the agglomeration of the constituents of the mixture by suitable shaping before cooking, preferably in the form of pellets whose consolidation continues during cooking then allowing their handling, transport, storage or landfill without formation of dust.
- the invention relates to a process of insolubilization and consolidation in the form of pellets of old pot lining from electrolysis tanks for the production of aluminum
- said pot lining consisting of carbon products and impregnated silico-aluminous products of fluorinated alkaline compounds and cyanides as well as their intimate mixture with various refractory pulverulent additives before heat treatment or cooking, characterized in that after introduction: of a first additive intended during cooking to fix the alkali metals, in particular sodium, coming from fluorinated compounds and which is chosen from the group of silicoaluminates, then from a second additive intended during cooking, on the one hand to combine, with or without fusion, with fluorinated impregnating compounds to form new stable and insoluble compounds such as CaF 2 , on the other hand, by its uncombined excess fraction , to ensure before but especially during and after cooking, the consolidation of the mixture, said second additive being chosen from the group of calcium oxides and salts and preferably cements and limestone mortars
- This consolidation has many advantages by allowing, for example, landfill or storage in a dense and thick bed of the inert final residue without the risk of crushing the pellets which have become sufficiently resistant or even in the case of a new use, the transport and handling without risk of spalling of said pellets with formation of dust and pollution of the atmosphere.
- cyanides CN ⁇ 1% of the total weight
- fluorinated compounds mainly in the state of sodium fluoride, which can represent up to 35% or even 40% of the total weight.
- the old, previously crushed pot lining is crushed to obtain particles of dimension less than 5 mm and preferably less than
- the first additive intended mainly during cooking to fix the alkali metals and in particular sodium, chosen from the group of silicoaluminates, is a feldspar or a clay such as for example kaolin or bentonite, some typical compositions of which are indicated in Table 1. below.
- the second additive intended during cooking to combine with or without fusion with the fluorinated impregnation compounds, in particular NaF, AIF 3 and Na 3 AlF ⁇ , while ensuring the consolidation of the agglomerated mixture during its elaboration, can be lime CaO, calcium carbonate CaC0 3 but is preferably chosen from the group of cements and calcareous mortars.
- the Applicant has advantageously experimented with Portland type quick-setting cements which, while having good performance in insolubilizing fluorine by combination in the form of CaF 2 , ensure excellent consolidation of the agglomerates during baking (see table 2).
- Another essential characteristic of the process is the shaping by agglomeration of the crushed spent pot lining mixture / additives before cooking.
- This shaping of the powder mixture by agglomeration can be obtained by any means for shaping known powder materials such as compression or extrusion of the mixture dry or slightly humidified. This gives pellets or granules which can then be enlarged and rounded in the form of pellets by granulation, but even more simply by direct granulation of the pre-humidified mixture at a humidity level preferably set between 15 % and 25% of the weight of the dry mixture, pellets with excellent cohesion are obtained as will be described later in the detailed implementation of the process.
- Cooking or heat treatment of the pellets must be carried out at a temperature of at least 700 ° C to decompose the cyanides, but without exceeding 950 ° C so as not to risk the onset of dissociation of the already stabilized fluorides.
- the temperature is preferably set between 800 ° C and 900 ° C (see table 3).
- the cooking time can vary from 1 hour to 6 hours depending on the nature of the additives and the weight composition of the mixture, but especially depending on the cooking method adopted and the average size of the pellets.
- the optimal cooking time is no more than 3 hours in a pass-through oven with cradles and 1 to 2 hours in a rotary oven or in a fluidized bed oven, the latter being particularly suitable for the process according to the invention taking into account the excellent cohesion of the dumplings during cooking in spite of the shocks and the effects of attrition between dumplings (see table 2).
- the carbon content of spent pot lining is very high and makes it possible to reach, after mixing, a carbon content of at least 25% in raw pellets, these can be used as auxiliary fuel in an oven incineration.
- the inert residue in the form of pellets can either be landfilled, stored or reused in a new application, for example as a fill for backfill.
- Crush resistance test consisting of dropping a steel ball of 11 grams at a height of 65 cm onto a dumpling; this in order to check the resistance of the pellets during loading and unloading.
- the result is expressed as a percentage of pellets that have remained intact.
- FIG. 1 is the schematic representation of the successive stages of the method.
- One tonne of spent pot lining 1 coming from the dry unmasking of aluminum production electrolysis tanks and constituting a complete mixture of silico-aluminous refractories and carbon blocks with a particle size of 0-700 mm is crushed and then ground A to obtain a powder product 2 with a particle size of 0-2.5 mm, the weight contents of carbon, fluorine, sodium, silicon and cyanide being 38.4%, 9.2%, 14.6%, 1 1, 1% and 0 respectively , 12%.
- the pulverulent product 2 is mixed B with on the one hand 500 kg of a first pulverulent additive 3 consisting of feldspar FHB200 (sodium feldspar albite type, a typical analysis of which is given in table 1) and on the other hand 500 kg of a second powder additive 4 consisting of Portland cement with rapid setting, for example Lafarge CEM cement 52, 5.
- a first pulverulent additive 3 consisting of feldspar FHB200 (sodium feldspar albite type, a typical analysis of which is given in table 1)
- a second powder additive 4 consisting of Portland cement with rapid setting, for example Lafarge CEM cement 52, 5.
- the resulting powder mixture 5 is moistened by spraying water 6 at a rate of 15% to 25% of the dry mix weight before being C-shaped in the state of pellets in a pelletizer constituted by an inclined circular table and in rotation allowing the formation of small nodules.
- These nodules grow by coating in contact with the humidified pulverulent mixture 5 which is continuously recycled, to form increasingly large pellets which are removed from the device when they reach the desired size, generally a diameter of between 6 mm and 20 mm and fixed in this case 10 mm.
- the raw dumplings 7 calibrated with a diameter of 10 mm and whose specific volume before cooking is between 1 and 1, 2 g / cm 3 are then baked for 1 hour at 900 ° CD in a fluidized bed reactor by adjusting appropriately the fluidization air flow.
- the fluorine content of the gases leaving the reactor at constant flow rate is checked by taking a gas sample every 15 minutes.
- the cooked pellets 8 representing 1600 kg of residue are then subjected to the various insolubilization control tests (according to standard NF-X31210) and mechanical strength. The following results were obtained:
- Na leachable% 0.1 7 mechanical strength: a) cohesion test (Turbula): good ( ⁇ 1% of fines) b) resilience test: 100% c) crush resistance test: 84%.
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Ceramic Engineering (AREA)
- Civil Engineering (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Business, Economics & Management (AREA)
- Emergency Management (AREA)
- Health & Medical Sciences (AREA)
- Toxicology (AREA)
- General Health & Medical Sciences (AREA)
- Materials Engineering (AREA)
- Structural Engineering (AREA)
- Organic Chemistry (AREA)
- Processing Of Solid Wastes (AREA)
- Electrolytic Production Of Metals (AREA)
- Cookers (AREA)
Abstract
Description
Claims
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
FR9614723A FR2756198B1 (en) | 1996-11-26 | 1996-11-26 | PROCESS FOR THE INSOLUBILIZATION AND CONSOLIDATION OF WASTE BRAKES FROM HALL-HEROULT ELECTROLYSIS TANKS |
FR9614723 | 1996-11-26 | ||
PCT/FR1997/002123 WO1998023551A1 (en) | 1996-11-26 | 1997-11-25 | Method for the insolubilisation and consolidation of used brasques from hall-heroult electrolyte vessels |
Publications (1)
Publication Number | Publication Date |
---|---|
EP0946449A1 true EP0946449A1 (en) | 1999-10-06 |
Family
ID=9498214
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP97947133A Withdrawn EP0946449A1 (en) | 1996-11-26 | 1997-11-25 | Method for the insolubilisation and consolidation of used brasques from hall-heroult electrolyte vessels |
Country Status (7)
Country | Link |
---|---|
US (1) | US5947888A (en) |
EP (1) | EP0946449A1 (en) |
AU (1) | AU726174B2 (en) |
CA (1) | CA2273004C (en) |
FR (1) | FR2756198B1 (en) |
NO (1) | NO325224B1 (en) |
WO (1) | WO1998023551A1 (en) |
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Publication number | Priority date | Publication date | Assignee | Title |
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GR1006144B (en) * | 2006-02-14 | 2008-11-07 | Isocon Α.Ε. | New type of plasticiser for clay-based mortars |
US8196533B2 (en) | 2008-10-27 | 2012-06-12 | Kentucky-Tennessee Clay Co. | Methods for operating a fluidized-bed reactor |
Family Cites Families (11)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4113832A (en) * | 1977-11-28 | 1978-09-12 | Kaiser Aluminum & Chemical Corporation | Process for the utilization of waste materials from electrolytic aluminum reduction systems |
US4763585A (en) * | 1987-09-08 | 1988-08-16 | Ogden Environmental Services | Method for the combustion of spent potlinings from the manufacture of aluminum |
WO1989012498A1 (en) * | 1988-06-24 | 1989-12-28 | Rolite, Inc. | Incineration residue treatment process and apparatus |
US5037286A (en) * | 1988-06-24 | 1991-08-06 | Rolite, Inc. | Incineration residue treatment apparatus |
US5365012A (en) * | 1990-07-04 | 1994-11-15 | Aluminium Pechiney | Process for the heat treatment of spent pot linings derived from Hall-Heroult electrolytic cells |
FR2664297B1 (en) * | 1990-07-04 | 1992-09-11 | Pechiney Aluminium | PROCESS FOR THE TREATMENT BY THERMAL SHOCK OF USED BRAZZERS FROM HALL-HEROULT ELECTROLYSIS TANKS. |
FR2669350B1 (en) * | 1990-11-16 | 1993-01-15 | Pechiney Aluminium | WET TREATMENT PROCESS OF WASTE BRAZES FROM HALL-HEROULT ELECTROLYSIS TANKS. |
WO1992020469A1 (en) * | 1991-05-16 | 1992-11-26 | Qubator Pty Limited | Process for converting spent pot liner |
US5164174A (en) * | 1991-10-11 | 1992-11-17 | Reynolds Metals Company | Detoxification of aluminum spent potliner by thermal treatment, lime slurry quench and post-kiln treatment |
JP3175981B2 (en) * | 1992-10-28 | 2001-06-11 | 株式会社東芝 | Trimming circuit |
US5772937A (en) * | 1996-10-15 | 1998-06-30 | Fuller Company | Method to produce aggregate products |
-
1996
- 1996-11-26 FR FR9614723A patent/FR2756198B1/en not_active Expired - Fee Related
-
1997
- 1997-11-25 US US08/977,537 patent/US5947888A/en not_active Expired - Fee Related
- 1997-11-25 CA CA 2273004 patent/CA2273004C/en not_active Expired - Fee Related
- 1997-11-25 EP EP97947133A patent/EP0946449A1/en not_active Withdrawn
- 1997-11-25 WO PCT/FR1997/002123 patent/WO1998023551A1/en not_active Application Discontinuation
- 1997-11-25 AU AU52292/98A patent/AU726174B2/en not_active Ceased
-
1999
- 1999-05-25 NO NO19992511A patent/NO325224B1/en not_active IP Right Cessation
Non-Patent Citations (1)
Title |
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See references of WO9823551A1 * |
Also Published As
Publication number | Publication date |
---|---|
NO992511D0 (en) | 1999-05-25 |
CA2273004A1 (en) | 1998-06-04 |
AU726174B2 (en) | 2000-11-02 |
NO325224B1 (en) | 2008-03-03 |
US5947888A (en) | 1999-09-07 |
FR2756198B1 (en) | 1998-12-18 |
AU5229298A (en) | 1998-06-22 |
FR2756198A1 (en) | 1998-05-29 |
CA2273004C (en) | 2007-05-15 |
WO1998023551A1 (en) | 1998-06-04 |
NO992511L (en) | 1999-07-26 |
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