EP2737091A1 - Method and device for treating a molten slag - Google Patents
Method and device for treating a molten slagInfo
- Publication number
- EP2737091A1 EP2737091A1 EP12750856.2A EP12750856A EP2737091A1 EP 2737091 A1 EP2737091 A1 EP 2737091A1 EP 12750856 A EP12750856 A EP 12750856A EP 2737091 A1 EP2737091 A1 EP 2737091A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- slag
- liquid
- molten slag
- alloy
- additive
- 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- Withdrawn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
- 239000002893 slag Substances 0.000 title claims abstract description 231
- 238000000034 method Methods 0.000 title claims abstract description 86
- 239000007788 liquid Substances 0.000 claims abstract description 92
- 239000000956 alloy Substances 0.000 claims abstract description 70
- 229910045601 alloy Inorganic materials 0.000 claims abstract description 69
- 238000005266 casting Methods 0.000 claims abstract description 52
- 239000000654 additive Substances 0.000 claims abstract description 51
- 230000000996 additive effect Effects 0.000 claims abstract description 46
- 238000007711 solidification Methods 0.000 claims abstract description 31
- 230000008023 solidification Effects 0.000 claims abstract description 31
- 238000001816 cooling Methods 0.000 claims abstract description 30
- 239000003513 alkali Substances 0.000 claims abstract description 20
- 239000000126 substance Substances 0.000 claims abstract description 20
- 239000012768 molten material Substances 0.000 claims abstract description 18
- 239000000378 calcium silicate Substances 0.000 claims abstract description 15
- 229910052918 calcium silicate Inorganic materials 0.000 claims abstract description 15
- OYACROKNLOSFPA-UHFFFAOYSA-N calcium;dioxido(oxo)silane Chemical compound [Ca+2].[O-][Si]([O-])=O OYACROKNLOSFPA-UHFFFAOYSA-N 0.000 claims abstract description 11
- 238000010310 metallurgical process Methods 0.000 claims abstract description 8
- 229910000831 Steel Inorganic materials 0.000 claims description 22
- 239000010959 steel Substances 0.000 claims description 22
- 239000011575 calcium Substances 0.000 claims description 18
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 claims description 17
- 229910052791 calcium Inorganic materials 0.000 claims description 16
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N silicon dioxide Inorganic materials O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 16
- 238000004519 manufacturing process Methods 0.000 claims description 15
- 239000010453 quartz Substances 0.000 claims description 14
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 claims description 11
- 239000011574 phosphorus Substances 0.000 claims description 11
- 229910052698 phosphorus Inorganic materials 0.000 claims description 11
- 150000004760 silicates Chemical class 0.000 claims description 11
- 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 9
- 239000011734 sodium Substances 0.000 claims description 9
- 235000012255 calcium oxide Nutrition 0.000 claims description 6
- 239000010881 fly ash Substances 0.000 claims description 6
- 235000012245 magnesium oxide Nutrition 0.000 claims description 6
- 229910052708 sodium Inorganic materials 0.000 claims description 6
- ZLMJMSJWJFRBEC-UHFFFAOYSA-N Potassium Chemical compound [K] ZLMJMSJWJFRBEC-UHFFFAOYSA-N 0.000 claims description 5
- HCWCAKKEBCNQJP-UHFFFAOYSA-N magnesium orthosilicate Chemical compound [Mg+2].[Mg+2].[O-][Si]([O-])([O-])[O-] HCWCAKKEBCNQJP-UHFFFAOYSA-N 0.000 claims description 5
- 239000000391 magnesium silicate Substances 0.000 claims description 5
- 229910052919 magnesium silicate Inorganic materials 0.000 claims description 5
- 235000019792 magnesium silicate Nutrition 0.000 claims description 5
- 239000011591 potassium Substances 0.000 claims description 5
- 229910052700 potassium Inorganic materials 0.000 claims description 5
- 150000001875 compounds Chemical class 0.000 claims description 4
- AXZKOIWUVFPNLO-UHFFFAOYSA-N magnesium;oxygen(2-) Chemical class [O-2].[Mg+2] AXZKOIWUVFPNLO-UHFFFAOYSA-N 0.000 claims description 4
- BVKZGUZCCUSVTD-UHFFFAOYSA-L Carbonate Chemical compound [O-]C([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-L 0.000 claims description 2
- 239000000203 mixture Substances 0.000 description 24
- 230000008569 process Effects 0.000 description 24
- 239000000047 product Substances 0.000 description 19
- 239000000463 material Substances 0.000 description 17
- 239000007789 gas Substances 0.000 description 14
- 238000007872 degassing Methods 0.000 description 11
- 239000012071 phase Substances 0.000 description 11
- 229940043430 calcium compound Drugs 0.000 description 10
- 239000008187 granular material Substances 0.000 description 10
- 150000002681 magnesium compounds Chemical class 0.000 description 10
- 238000002844 melting Methods 0.000 description 10
- 230000008018 melting Effects 0.000 description 10
- 230000015572 biosynthetic process Effects 0.000 description 9
- 239000002585 base Substances 0.000 description 8
- 238000006243 chemical reaction Methods 0.000 description 8
- 230000005496 eutectics Effects 0.000 description 8
- 230000002829 reductive effect Effects 0.000 description 8
- 238000005275 alloying Methods 0.000 description 7
- 238000010586 diagram Methods 0.000 description 7
- 230000035882 stress Effects 0.000 description 7
- 230000008901 benefit Effects 0.000 description 6
- 239000006227 byproduct Substances 0.000 description 5
- 239000007795 chemical reaction product Substances 0.000 description 5
- 229910052500 inorganic mineral Inorganic materials 0.000 description 5
- 239000007791 liquid phase Substances 0.000 description 5
- 239000011777 magnesium Substances 0.000 description 5
- 239000000155 melt Substances 0.000 description 5
- 239000011707 mineral Substances 0.000 description 5
- 235000010755 mineral Nutrition 0.000 description 5
- 230000008646 thermal stress Effects 0.000 description 5
- 238000011084 recovery Methods 0.000 description 4
- 239000004576 sand Substances 0.000 description 4
- 230000007704 transition Effects 0.000 description 4
- 229910002092 carbon dioxide Inorganic materials 0.000 description 3
- 239000000919 ceramic Substances 0.000 description 3
- 230000007423 decrease Effects 0.000 description 3
- 238000009434 installation Methods 0.000 description 3
- 229910052749 magnesium Inorganic materials 0.000 description 3
- 238000010587 phase diagram Methods 0.000 description 3
- 229910001950 potassium oxide Inorganic materials 0.000 description 3
- -1 silicate compound Chemical class 0.000 description 3
- 229910001948 sodium oxide Inorganic materials 0.000 description 3
- 230000009466 transformation Effects 0.000 description 3
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 2
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 2
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- BPQQTUXANYXVAA-UHFFFAOYSA-N Orthosilicate Chemical compound [O-][Si]([O-])([O-])[O-] BPQQTUXANYXVAA-UHFFFAOYSA-N 0.000 description 2
- 229910000805 Pig iron Inorganic materials 0.000 description 2
- 150000001399 aluminium compounds Chemical class 0.000 description 2
- 229940077746 antacid containing aluminium compound Drugs 0.000 description 2
- 229910052799 carbon Inorganic materials 0.000 description 2
- 230000008859 change Effects 0.000 description 2
- 238000005253 cladding Methods 0.000 description 2
- 239000000470 constituent Substances 0.000 description 2
- 239000013078 crystal Substances 0.000 description 2
- 230000006872 improvement Effects 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- CHWRSCGUEQEHOH-UHFFFAOYSA-N potassium oxide Chemical compound [O-2].[K+].[K+] CHWRSCGUEQEHOH-UHFFFAOYSA-N 0.000 description 2
- 238000003303 reheating Methods 0.000 description 2
- 239000010703 silicon Substances 0.000 description 2
- 229910052710 silicon Inorganic materials 0.000 description 2
- 235000008733 Citrus aurantifolia Nutrition 0.000 description 1
- CWYNVVGOOAEACU-UHFFFAOYSA-N Fe2+ Chemical compound [Fe+2] CWYNVVGOOAEACU-UHFFFAOYSA-N 0.000 description 1
- 235000019738 Limestone Nutrition 0.000 description 1
- 241001062472 Stokellia anisodon Species 0.000 description 1
- 235000011941 Tilia x europaea Nutrition 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 229910021538 borax Inorganic materials 0.000 description 1
- 150000001674 calcium compounds Chemical class 0.000 description 1
- 239000001569 carbon dioxide Substances 0.000 description 1
- 150000004649 carbonic acid derivatives Chemical class 0.000 description 1
- 239000004568 cement Substances 0.000 description 1
- 238000010924 continuous production Methods 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 238000004090 dissolution Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000006253 efflorescence Methods 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 239000004571 lime Substances 0.000 description 1
- 239000006028 limestone Substances 0.000 description 1
- 239000011344 liquid material Substances 0.000 description 1
- 229910001338 liquidmetal Inorganic materials 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 239000011148 porous material Substances 0.000 description 1
- 150000003112 potassium compounds Chemical class 0.000 description 1
- 230000002265 prevention Effects 0.000 description 1
- 206010037844 rash Diseases 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 239000000376 reactant Substances 0.000 description 1
- 230000009257 reactivity Effects 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 238000007670 refining Methods 0.000 description 1
- 230000000630 rising effect Effects 0.000 description 1
- 239000004328 sodium tetraborate Substances 0.000 description 1
- 235000010339 sodium tetraborate Nutrition 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 230000000087 stabilizing effect Effects 0.000 description 1
- 238000003860 storage Methods 0.000 description 1
- 230000001629 suppression Effects 0.000 description 1
- 230000036962 time dependent Effects 0.000 description 1
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N titanium dioxide Inorganic materials O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 description 1
- 230000000007 visual effect Effects 0.000 description 1
- 230000003313 weakening effect Effects 0.000 description 1
- 238000004876 x-ray fluorescence Methods 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21B—MANUFACTURE OF IRON OR STEEL
- C21B3/00—General features in the manufacture of pig-iron
- C21B3/04—Recovery of by-products, e.g. slag
- C21B3/06—Treatment of liquid slag
-
- 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
- C04B18/04—Waste materials; Refuse
- C04B18/14—Waste materials; Refuse from metallurgical processes
- C04B18/141—Slags
- C04B18/142—Steelmaking slags, converter slags
-
- 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
- C04B18/04—Waste materials; Refuse
- C04B18/14—Waste materials; Refuse from metallurgical processes
- C04B18/141—Slags
- C04B18/145—Phosphorus slags
-
- 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
- C04B5/00—Treatment of metallurgical slag ; Artificial stone from molten metallurgical slag
- C04B5/06—Ingredients, other than water, added to the molten slag or to the granulating medium or before remelting; Treatment with gases or gas generating compounds, e.g. to obtain porous slag
-
- 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
- C22B7/04—Working-up slag
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21B—MANUFACTURE OF IRON OR STEEL
- C21B2400/00—Treatment of slags originating from iron or steel processes
- C21B2400/02—Physical or chemical treatment of slags
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21B—MANUFACTURE OF IRON OR STEEL
- C21B2400/00—Treatment of slags originating from iron or steel processes
- C21B2400/04—Specific shape of slag after cooling
- C21B2400/044—Briquettes or moulded bodies other than sheets
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/20—Recycling
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
- Y02W30/00—Technologies for solid waste management
- Y02W30/50—Reuse, recycling or recovery technologies
-
- 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 present invention relates to a method for treating a calcium silicate-containing molten slag formed during a metallurgical process according to the preamble of Claim 1. Furthermore, the invention relates to a device according to the preamble of Claim 16. In addition, the invention relates to a method according to Claim 21.
- one of the byproducts formed is a calcium silicate-containing residue stream in the form of a molten slag.
- this residue stream is referred to as a steel slag, and this molten slag is produced both in the production of pig iron and in the refining of the pig iron to steel.
- thermal phosphorus production the residue stream is referred to as phosphorus slag.
- These calcium silicate-containing molten slags are characterized by a high content of mineral components (mostly silicon and aluminium compounds).
- a composition of a steel slag which has been determined, for example, by x-ray fluorescence analysis typically contains CaO (40-50%), Si0 2 (10-20 %) , A1 2 0 3 (1-3%), MgO (5-10%), FeO (10-40%) and a small amount of Na 2 0 ( ⁇ 1%) as components.
- other elements may also be present. All of the percentages mentioned above and below are percentages by weight.
- a phosphorus slag is typically composed of CaO (45-50%), Si0 2 (40-45%), A1 2 0 3 (1- 3%), MgO (1-2%), P 2 0 5 (0-3%) and a small amount of Na 2 0 ( ⁇ 1%).
- other elements may also be present.
- the steel slag in particular contains reactive calcium and magnesium compounds. Due to the reactivity of these calcium and magnesium compounds, these calcium and magnesium compounds undergo further reactions in the solidified state when exposed to air and/or moisture. Effectively, the calcium and magnesium compounds formed during solidification of the steel slag are metastable.
- steel slags are only used to a very limited degree for high-performance applications. Annually, many hundreds of millions of tonnes of steel slag are being produced worldwide. Most steel slag is either taken to dumping sites or (in the case of a useful application) is used in relatively low-performance infrastructural applications.
- Phosphorus slag is also produced in large quantities. Although phosphorus slag often does not contain any reactive components, it too is only used for low-performance applications (if it is used at all).
- blast furnace slags are also already being used in high-performance applications in the cement industry.
- the molten slag contains a supersaturation of gases which do not escape from the molten slag or only to an insufficient degree during cooling down, remain in the solidified slag and can cause (local) weakening of the product due to, for example, the formation of coarse enclosures.
- the molten slag is removed from the production process as quickly as possible without considering the processing thereof. In this case, the molten slag is often cooled down as quickly as possible until it solidifies. This generally results in a molten slag which is made up of relatively weak material which may contain many (cooling) cracks.
- the smelt still contains reactive metastable constituents which only after cooling down and often in the long term lead to afterreactions in the solidified phase. Depending on the specific reactant, this afterreaction can result in an increase in volume. This may cause the formation of cracks in the product or other (visual) damage, such as for example by efflorescence. 4.
- the molten slag to form stone-like products having a great wall thickness (such as blocks) relatively large temperature differences often occur during solidification.
- the slag is mixed (intimately) with a gas which is supplied from the outside in an installation (part) which is specifically suited for this purpose, e.g. a gas (for example C0 2 or Ar) is allowed to flow through the slag in order to cause the melt to move vigorously, resulting in the dissolving power for the gases decreasing and a significant part of the dissolved gases being released.
- a gas for example C0 2 or Ar
- This also usually takes place in a separate (reaction) vessel which is provided with the necessary inlet and outlet for the gases.
- CA 2 278 099 describes a process by means of which high-performance building products are obtained, starting from a mineral melt.
- the essence of this invention is that minerals are added in relatively large amounts (5 to 35%) in order to affect the composition and furthermore that the melt is pretreated in a vessel in which various kinds of deaeration are carried out and then, after casting, the moulds are placed in a furnace system in which the desired properties for the end product are achieved by reheating and cooling down the melt several times.
- Japanese patent JP2009270132 mentions converting the reactive components in the molten slag into stable compounds.
- an additive which is not described in any more detail is mixed in with the molten mass, following which the hot mixture is heated further to temperatures in excess of 1600 °C in order to cause the desired reactions to take place.
- Japanese patent JP6329450 mentions mixing mineral (semi)liquid molten slag with quartz or quartz-containing by-products using a modified bulldozer in order to produce stabilized granules.
- British patent GB 2 437 796 A mentions that a (glass) ceramic product based on blast furnace slag is produced by adding relatively large amounts of magnesium compounds. Subsequently, the other (process) properties of the blast furnace slag are improved by the addition of borax and rutile in order to produce a ceramic product (for example tiles).
- the invention relates to the abovementioned method
- the method furthermore comprises:
- a first additive which comprises at least one substance containing an alkali element to the separated liquid molten slag in order to form a liquid slag alloy for reducing a solidification point of the liquid slag alloy with respect to a solidification point of the molten slag
- the liquid slag alloy contains between approximately 1 and approximately 6% of alkali element oxide component, and the alkali element is selected from a group including at least one of sodium and potassium.
- the invention provides that by changing the composition of the molten slag, the solidification point (or the temperature of the solidification range) of the molten slag is reduced. Without wishing to limit oneself to one specific theoretical explanation, it is assumed that the change in the composition of the molten slag results in a composition which has a lower melting point in the phase diagram and has, for example, a more pronounced eutectic character of the liquid phase.
- the method has the advantage that the viscosity of the liquid molten slag reduces.
- the addition of the alkali element-containing substance reduces the viscosity of the molten slag, due to the alkali atoms preventing or suppressing a polymerisation of the silicate constituents of the molten slag. Due to the alkali elements being monovalent, the prevention/suppression is stronger than that of elements having a higher valency.
- the lower viscosity makes it easier for the dissolved gases to escape from the liquid.
- an improved supply to the casting die volume from the liquid phase can be achieved during the solidification process, so that a relatively thinner wall thickness of the moulded product can be achieved.
- the lowering of the solidification point increases the temperature difference between the actual process temperature of the molten slag and the solidification point, the lowering of the solidification point can also be used for significant energy recovery from the liquid slag.
- the invention makes it possible to form products by means of a continuous process, comparable to the possibilities in the steel industry.
- the invention provides a method as described above, in which the alkali element is selected from potassium and sodium. These elements have the desired effect and do not adversely affect the metastable Ca and Mg components in the molten slag.
- the invention provides a method as described above, wherein the calcium silicate-containing molten slag is a steel slag or a thermal phosphorus slag containing less than 1% Na 2 0.
- the invention provides a method as described above, wherein the liquid slag alloy contains between 1% and 5% alkali element oxide component, wherein the alkali element is selected from a group of at least one of sodium and potassium. Addition of such amounts to this composition results in a lowering of the solidification point in the order of magnitude of 200 to 300° (Celsius).
- the invention provides a method as described above, wherein the alkali element-containing substance is selected from a carbonate or a halogenide compound.
- Alkali carbonates decompose, during which process C0 2 is released which is finely distributed in the slag and can thus serve as a trigger for forming gas bubbles for gases dissolved in the slag, thereby assisting degassing.
- the use of alkali halogenide has the advantage that the halogenide can react with the metastable Ca and/or Mg components, in which case more stable Ca and/or Mg components are formed.
- the invention provides a method as described above, comprising the addition of a second additive comprising silicate compounds, wherein an amount of the second additive to be added depends on an amount of unstable reactive calcium and/or magnesium oxides, and wherein an active component of the silicate compounds to be added is not calcium or magnesium silicate and, in addition, fine-grained (preferably ⁇ 100 micrometres).
- This second additive serves to further stabilize the metastable Ca and Mg components in the slag in the form of a respective silicate compound.
- the invention provides a method as described above, wherein the second additive is an amorphous substance.
- This type of substance needs less energy in order to pass to the liquid phase, unlike crystalline substances which require additional energy in order to break the crystal lattice.
- the amorphous substance can become liquid more quickly and react with the metastable Ca and Mg components in the molten slag.
- the invention provides a method as described above, wherein the amorphous substance is fly ash, in particular carbon-containing fly ash. It has been found that fly ash from coal-fired power stations is highly suitable for this application. Moreover, the carbon in the fly ash amplifies the degassing by the formation of carbon dioxide in the liquid slag alloy.
- the invention provides a method as described above, wherein the silicate compounds of the second additive do not comprise quartz. In this manner, the quartz content of the slag alloy is prevented from rising, and an increase of the thermal stress in the moulded product as a result of the 'quartz transition' at approximately 573 °C is prevented.
- the invention provides a method as described above, comprising withdrawing heat from the liquid slag alloy after the addition of at least the first additive and before casting.
- the invention provides a method as described above, comprising lowering the temperature of the liquid slag alloy to a temperature which is
- the invention provides a method as described above, comprising actively mixing the liquid molten slag and the at least first additive during the addition of at least the first additive.
- the invention provides a method as described above, comprising the addition of vibration energy to the liquid slag alloy and/or the liquid molten slag before casting it into the casting die.
- vibrations improves the degassing of the liquid slag.
- the reduction of the viscosity by the addition of the first additive facilitates the result obtained by the vibrations.
- the invention provides a method as described above, wherein the liquid slag alloy is divided into several casting streams before casting.
- the invention provides a method as described above, wherein, after casting into the casting die, the cooling rate in a range around 573 °C is adjusted to the amount of quartz present in the slag alloy.
- the invention comprises a method as described above, comprising granulating the slag alloy during casting.
- the invention also relates to the above-described device, comprising an inlet for a liquid molten slag which originates from a production process of a molten material from ore in a furnace, wherein the inlet is connected to the furnace for receiving the liquid molten slag; an outlet for casting the received liquid molten slag into a casting die; a conveyor runner which extends from the inlet to the outlet for enabling the liquid molten slag to flow from the inlet to the outlet, wherein the device furthermore comprises an inlet for adding at least one additive to the received liquid molten slag in order to form a liquid slag alloy, wherein the conveyor runner is provided with one or more blades or guides for mixing the at least first additive and the flowing liquid slag alloy during use.
- Fig. 1 shows a process diagram of a method according to an embodiment of the invention
- Figs. 2a, 2b diagrammatically show a device according to an embodiment of the invention.
- Fig. 1 shows a process diagram of a method of treating a molten slag which can be used in connection with a metallurgical process.
- a liquid base material often a liquid metal
- the ore(s) is (are) the raw material which contains the base material to be recovered, such as iron ore, or a phosphorus-containing ore, a non-ferrous ore and additional components, such as for example limestone.
- additive(s) are added to release or stabilize the base material from the ore.
- these processes produce a by-product in the form of a molten slag which is formed from a reaction product of the secondary components of the ore and/or components of the additive(s).
- Fig. 1 shows a flow diagram of a process 100 for treating and processing the molten slag.
- molten slag is separated from the liquid base material.
- the liquid base material together with the molten slag is situated in a furnace or reactor, where a process temperature prevails which is determined by the (metallurgical) process in order to release the base material.
- the process temperature is approximately between 1500 and 1700 °C.
- the molten slag therefore has a temperature which substantially corresponds to the process temperature in the thermal processing of ore.
- at least a first additive is added to the molten slag.
- An additive contains one or more alkali-containing components (elements or compounds) which have the property that they form an alloy using the separated liquid molten slag or that they react with the separated liquid slag, wherein the composition of the liquid slag alloy changes in such a manner that the solidification point or the solidification range temperature is lowered.
- a eutectic or peritectic composition is obtained or at least a composition which has a lower melting point and, according to the phase theory, comes closer to a eutectic or peritectic composition than the composition of the separated molten slag.
- the molten slag is a calcium silicate-containing residual product which is characterized by a high content of mineral components (mostly silicon and aluminium compounds).
- the steel slag may also contain reactive metastable calcium and magnesium compounds.
- the first additive comprises an alkali element-containing substance, such as sodium, and/or potassium compounds.
- This element ensures that the composition of the molten slag "moves" in the direction of a eutectic or peritectic point (range) which is known from phase diagrams and/or phase information for molten slag material.
- the liquid slag alloy contains between 1% and 5% of sodium and/or potassium oxide compound (in % by weight) or has a composition range between approximately 1% and approximately 6% of sodium or potassium oxide, or between approximately 2% and approximately 4% of sodium or potassium oxide.
- a second additive is optionally added for stabilizing the reactive calcium and/or magnesium compounds in the molten slag.
- This second additive contains silicate-containing substances which bond with the reactive calcium and magnesium compounds to form a stable calcium silicate and magnesium silicate, respectively. It will be clear that the composition of the separated liquid molten slag is determined before this alloying or reaction step. On the basis thereof, it can then be determined which amount of first additive and, if required, which amount of second additive is to be added.
- step 103 the additive(s) added in step 102 is (are) actively mixed with the molten slag in order to assist the alloying/reaction process. Mixing creates a liquid slag alloy from the molten slag.
- the solidification point (or melting point) thereof will be changed (i.e. lowered).
- the melting point is lowered in the direction of the minimum liquidus temperature which occurs at the eutecticum by "moving" to the eutectic point in the phase diagram.
- the slag thus remains liquid down to relatively low temperatures than without alloying or reaction step 102. For a steel slag, this results in a lowering of the temperature from approx. 1500 to approx. 1200 °C.
- the alloying of the slag as described above has the result that the solidification range is reduced in relative terms (with a modified, but non-eutectic composition) and the solidification range only takes place at the relatively lower temperature than with the separated liquid slag.
- the 'two-phase' range in which the slag consists of a solid and a liquid component is reduced by the alloying step moves to a lower temperature, which increases the castability of the slag alloy.
- phase systems may be binary, ternary, quaternary or of an even higher order.
- the second additive in an embodiment is an amorphous substance: compared to crystalline substances, a substance having an amorphous structure has the advantage that no transformation of the crystal structure to the liquid phase has to take place. As a result thereof, mixing or dissolution of the additive(s) is facilitated and accelerated in relative terms.
- the method comprises that the slag alloy is subjected to a degassing treatment.
- Degassing may take place by shaking the slag alloy, in which case gas bubbles can escape from the slag alloy. With this form of degassing, the amount of residual gas in the slag alloy decreases, so that an improved solidification structure of the slag is achieved. This step is also advantageous in order to reduce the build-up of internal stress in the solidified slag by any gas which may be present.
- the degassing is also improved by the added additive(s) which, inter alia, result in a lower viscosity.
- a step 104 heat is actively withdrawn from the slag alloy, for example by means of a heat-exchanging element.
- a heat-exchanging element As has already been explained above, the formation of the slag alloy lowers the melting/solidification point (or the
- the energy recovery 104 can also take place (at least partly) simultaneously with the addition phase 102 and/or the mixing phase 103, depending on the actual temperature of the molten slag.
- the temperature of the slag alloy can be lowered to about 50° (degrees Celsius) above the melting/solidification point (or the temperature of the start of solidification). Due to the reduced viscosity of the slag alloy, the liquidity is sufficient at this point in time for carrying out a casting process.
- the process diagram comprises two alternatives 105 - 107; 108 - 1 10 for the further treatment of the cooled-down liquid slag alloy.
- the liquid slag alloy is cast into a casting die in step 105.
- this step comprises dividing the slag alloy into a number (more than one) casting streams. This has the advantage that the exchange of gases from the slag alloy to the atmosphere is improved.
- the slag alloy in the casting die solidifies and cools down. Due to the lowered viscosity, a thinner wall thickness and higher form definition of the moulded product is possible than with a steel slag from the prior art.
- molten slag which has already solidified in the casting die in the form of a stack of pieces or granules between which there are spaces.
- the liquid molten slag is cast thereon and, due to its low viscosity, fills the spaces between the pieces or granules. In addition, this reduces the wall thickness of the melt in the mould, so that in addition fewer thermal stresses will occur.
- the pieces should preferably have the same composition as the melt in order to obtain an end product which is as homogenous as possible. Due to the fact that a part of the mass in the casting die has already solidified, the total shrinkage in the casting die volume resulting from the solidification of the liquid material which is added will be relatively low. In this way, it is possible to produce a product with a reduced degree of thermal stress.
- the cooling down is controlled in such a manner that the region of the so-called quartz transition (that is to say the phase transformation of quartz at approx. 573 °C) is passed through at a low cooling rate.
- This phase transformation is accompanied by a change in volume which may generate a mechanical stress in the cast material.
- a second alternative 108 - 1 10 for the further treatment of the liquid slag alloy follows after the step 104 of cooling down to close to the eutectic point.
- the liquid slag alloy is cast and granulated in step 108, that is to say the solidified slag alloy material consists of granular material, granules.
- the granules are collected and held in a storage volume.
- a subsequent step 109 which may, at least in time, partly coincide with the granulating process 108, the granules are cooled down.
- step 109 is used to withdraw heat (forced cooling) from the granules for the purpose of, for example, energy recovery.
- This forced cooling is advantageously possible because, although any increased thermal and/or internal stress resulting from the forced cooling may lead to the formation of cracks and breakage of the solidified slag material, in granules cracks in and/or crumbling of the material is permissible.
- step 110 the cooled down granules are collected as an end product.
- step 110 the process diagram ends with step 112 in this second variant.
- Figs. 2a, 2b diagrammatically show a device according to an embodiment of the invention.
- the device 200 is configured for use in carrying out the method 100 according to the invention.
- the device 200 comprises a tubular body 201.
- the tubular body 201 is provided with an inlet 202.
- the inlet 202 is configured to receive the liquid molten slag from the furnace.
- the inlet may be coupled to an outlet of the furnace or may be provided with, for example, an opening where a casting stream 300 from the furnace can be introduced into the tubular body.
- the tubular body is provided with an outlet 203.
- the tubular body is provided with an insulating cladding, for example in the form of a refractory layer.
- the tubular body is arranged at an angle in such a way that, compared to ground level, the inlet is situated above the outlet. Furthermore, the inlet 202 is configured to receive an additive stream 301 to form the slag alloy with the molten slag material.
- the tubular body 201 On an internal wall 201a of the tubular body 201, a number of mixing blades or ridges 205 are arranged which are configured, in use, to disturb a flow of the combination of molten slag 300 and additives 301 flowing past, resulting in an improvement in the mixing of the slag alloy and the additives and in an improvement in the degassing.
- the tubular body 201 has a length which is such that, during the passage time of the combination of flowing molten slag 300 and additives 301 , the formation of the slag alloy (that is to say the formation of the mainly eutectic or peritectic composition) is achieved/completed.
- the length may also depend on a distance to be bridged between the inlet location from the furnace and a processing location of the slag alloy.
- the tubular body has a diameter between approximately 20 and approximately 40 cm.
- the device 200 is also provided with a vibrating or shaking installation 206, 207 which is configured to supply vibration energy to the tubular body 201.
- a vibrating or shaking installation 206, 207 which is configured to supply vibration energy to the tubular body 201.
- the supply of vibrations makes it easier for the gas bubbles present in the slag alloy to escape, as a result of which the structure of the solidified slag alloy has fewer large inclusions and the porosity can be controlled or reduced.
- pores of a similar size such as are found in, for example, sand lime and (foamed) concrete are usually acceptable in the moulded slag product.
- the outlet 203 for the discharge of the slag alloy is situated at the end of the tubular body 201.
- a heat-exchanging element 208 is connected to the outlet 203 and is configured to collect the liquid slag alloy after it has passed through the tubular body 201 and to withdraw heat from the slag alloy which is in contact with the heat- exchanging element.
- the heat-exchanging element comprises a heat-conducting plate 208 which is provided with ducts 209 on the inside.
- a liquid medium can be passed through the ducts 209 in order to withdraw heat from the heat-conducting plate 208.
- the heat-exchanging element is controlled in such a manner that the liquid slag alloy is cooled to approximately 50° (Celsius) above the melting point of the slag alloy.
- the heat which has been withdrawn can be used as a source of heat in other locations, for example within the installation(s) where this process is being carried out, and it is also possible to apply energy-recovery techniques to the heat (stream) which has been withdrawn.
- Fig. 2b shows a cross section of the tubular body at the location of the line Ilb-IIb in Fig. 2a.
- the tubular body 201 comprises an insulating cladding which is situated on the inner wall of the tubular body or at least on the part of the inner wall with which the liquid slag could come into contact.
- one of the mixing blades 205 is visible in the bottom section (which is situated at a lower level) of the tubular body .
- the mixing blade 205 is configured as a body which tapers from the wall, possibly as a plate-shaped or fin-shaped body.
- the device according to the invention can also be used in a method in which a silicate- containing additive is added to the molten slag.
- the aim of this method is to transform the metastable or reactive calcium and/or magnesium compounds into stable components in the molten slag.
- the method relates to a treatment of a calcium silicate-containing molten slag in a metallurgical process, comprising:
- the method furthermore comprises:
- adding at least an additive which comprises silicate compounds wherein an amount of this additive to be added is dependent on an amount of unstable reactive calcium and/or magnesium oxides in the molten slag, and wherein an active component of the silicate compounds to be added is not calcium or magnesium silicate.
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Abstract
A method for treating a calcium silicate-containing molten slag in a metallurgical process comprises: - producing a molten material from ore in a furnace, wherein a liquid molten slag is formed on the surface of the molten material; - separating the liquid molten slag from the molten material; - casting the separated liquid molten slag into a casting die; - cooling down of the molten slag in the casting die; wherein the method furthermore comprises: prior to casting, adding at least a first additive which comprises at least one alkali element-containing substance to the separated liquid molten slag in order to form a liquid slag alloy for reducing a solidification point of the liquid slag alloy with respect to a solidification point of the molten slag.
Description
METHOD AND DEVICE FOR TREATING A MOLTEN SLAG
The present invention relates to a method for treating a calcium silicate-containing molten slag formed during a metallurgical process according to the preamble of Claim 1. Furthermore, the invention relates to a device according to the preamble of Claim 16. In addition, the invention relates to a method according to Claim 21.
In the prior art, various processes are known in which ores are converted at high temperatures into, on the one hand, the intended (metallurgical) product and, on the other hand, into one or more residue streams/by-products.
Inter alia in steel production and thermal phosphorus production, one of the byproducts formed is a calcium silicate-containing residue stream in the form of a molten slag. In the known steel production processes, this residue stream is referred to as a steel slag, and this molten slag is produced both in the production of pig iron and in the refining of the pig iron to steel. In thermal phosphorus production, the residue stream is referred to as phosphorus slag.
These calcium silicate-containing molten slags are characterized by a high content of mineral components (mostly silicon and aluminium compounds). A composition of a steel slag which has been determined, for example, by x-ray fluorescence analysis typically contains CaO (40-50%), Si02 (10-20 %) , A1203 (1-3%), MgO (5-10%), FeO (10-40%) and a small amount of Na20 (<1%) as components. In addition, other elements may also be present. All of the percentages mentioned above and below are percentages by weight.
A phosphorus slag is typically composed of CaO (45-50%), Si02 (40-45%), A1203 (1- 3%), MgO (1-2%), P205 (0-3%) and a small amount of Na20 (<1%). In addition, other elements may also be present.
The steel slag in particular contains reactive calcium and magnesium compounds. Due to the reactivity of these calcium and magnesium compounds, these calcium and magnesium compounds undergo further reactions in the solidified state when exposed to air and/or moisture. Effectively, the calcium and magnesium compounds formed during solidification of the steel slag are metastable.
Partly due to the presence of these reactive components (which has implications with respect to durability and the environment), steel slags are only used to a very limited degree for high-performance applications.
Annually, many hundreds of millions of tonnes of steel slag are being produced worldwide. Most steel slag is either taken to dumping sites or (in the case of a useful application) is used in relatively low-performance infrastructural applications.
Phosphorus slag is also produced in large quantities. Although phosphorus slag often does not contain any reactive components, it too is only used for low-performance applications (if it is used at all).
It is important to note that the abovementioned problem is aimed at the slags not originating from blast furnaces for the steel production and to molten slags originating from the non-ferro industry due to these having a completely different composition than the blast furnace slags.
In addition, blast furnace slags are also already being used in high-performance applications in the cement industry.
The common factor of the molten slags which are the subject of the abovementioned problem is that a strong and durable stone-like material can be produced during cooling down, provided that a number of inherent problems can be solved:
1. The molten slag contains a supersaturation of gases which do not escape from the molten slag or only to an insufficient degree during cooling down, remain in the solidified slag and can cause (local) weakening of the product due to, for example, the formation of coarse enclosures.
2. In practice, due to its status as a by-product, the molten slag is removed from the production process as quickly as possible without considering the processing thereof. In this case, the molten slag is often cooled down as quickly as possible until it solidifies. This generally results in a molten slag which is made up of relatively weak material which may contain many (cooling) cracks.
3. In some cases (such as with the steel slag), the smelt still contains reactive metastable constituents which only after cooling down and often in the long term lead to afterreactions in the solidified phase. Depending on the specific reactant, this afterreaction can result in an increase in volume. This may cause the formation of cracks in the product or other (visual) damage, such as for example by efflorescence. 4. When casting the molten slag to form stone-like products having a great wall thickness (such as blocks) relatively large temperature differences often occur during solidification. These are caused by the fact that the molten slag has a relatively low thermal conduction coefficient, the molten slag in the core of the moulded piece still
has a high temperature and the molten slag is already cooling down (to a significant degree) on the outside and has possibly already solidified. These temperature differences cause thermal tensions in the product which may result in a decrease in strength or even to the formation of cracks and other forms of damage in the product. In a number of patents, including in WO 0104064, CA 2 278 099, US 5,720,835, RU 2297396, various methods are mentioned to achieve degasification of the supersaturated molten slag:
In this case, the slag is mixed (intimately) with a gas which is supplied from the outside in an installation (part) which is specifically suited for this purpose, e.g. a gas (for example C02 or Ar) is allowed to flow through the slag in order to cause the melt to move vigorously, resulting in the dissolving power for the gases decreasing and a significant part of the dissolved gases being released. This also usually takes place in a separate (reaction) vessel which is provided with the necessary inlet and outlet for the gases.
These methods are intended to achieve (almost) complete degassing. In so far as they are discussed here, residence times of several hours are mentioned. In this case, additives and other components are usually mixed in simultaneously which may also affect the required residence time. CA 2 278 099 describes a process by means of which high-performance building products are obtained, starting from a mineral melt. The essence of this invention is that minerals are added in relatively large amounts (5 to 35%) in order to affect the composition and furthermore that the melt is pretreated in a vessel in which various kinds of deaeration are carried out and then, after casting, the moulds are placed in a furnace system in which the desired properties for the end product are achieved by reheating and cooling down the melt several times.
In patent GB 986,289 (Slagceram), the composition of the molten slag is changed significantly by the addition of large amounts of sand (> 20%) which, inter alia, serves to be able to produce a glass-like product (such as a ceramic roof tile). Furthermore, the mixture of sand and molten slag obtained has to be kept at a high temperature for several hours in order to enable the sand to dissolve and react. A complicated temperature cycle involving cooling down and reheating is performed in order to produce a desired structure of the mixture in this case as well.
Japanese patent JP2009270132 mentions converting the reactive components in the molten slag into stable compounds. In this case, an additive which is not described in
any more detail is mixed in with the molten mass, following which the hot mixture is heated further to temperatures in excess of 1600 °C in order to cause the desired reactions to take place.
Japanese patent JP6329450 mentions mixing mineral (semi)liquid molten slag with quartz or quartz-containing by-products using a modified bulldozer in order to produce stabilized granules.
British patent GB 2 437 796 A mentions that a (glass) ceramic product based on blast furnace slag is produced by adding relatively large amounts of magnesium compounds. Subsequently, the other (process) properties of the blast furnace slag are improved by the addition of borax and rutile in order to produce a ceramic product (for example tiles).
Dutch patent NL 1003885 mentions the invention of a runner system for conveying molten material at high temperatures. This runner system comprises a runner provided with a steel outer casing with a heatable refractory inside in order to provide excessive temperature stresses in the runner.
It is an object of the invention to provide a method which improves the processability of the molten slag. It is also an object to improve the structure of the solidified molten slag and to make the use thereof in relatively high-performance applications possible. Therefore, the invention relates to the abovementioned method
comprising:
- producing a molten material from ore in a furnace, wherein a liquid molten slag is formed on the surface of the molten material;
- separating the liquid molten slag from the molten material;
- casting the separated liquid molten slag into a casting die;
- cooling down the molten slag in the casting die;
wherein the method furthermore comprises:
prior to casting, adding at least a first additive which comprises at least one substance containing an alkali element to the separated liquid molten slag in order to form a liquid slag alloy for reducing a solidification point of the liquid slag alloy with respect to a solidification point of the molten slag,
wherein the liquid slag alloy contains between approximately 1 and approximately 6% of alkali element oxide component, and the alkali element is selected from a group including at least one of sodium and potassium.
The invention provides that by changing the composition of the molten slag, the solidification point (or the temperature of the solidification range) of the molten slag is reduced. Without wishing to limit oneself to one specific theoretical explanation, it is assumed that the change in the composition of the molten slag results in a composition which has a lower melting point in the phase diagram and has, for example, a more pronounced eutectic character of the liquid phase.
By lowering the solidification (range) point, the thermal stresses caused by the temperature differences and the differences in thermal expansion of the solidified material associated therewith will decrease. The occurrence of, for example, cracks in the solidified material will be significantly reduced. This makes it possible to process the moiten slag to form relatively large moulded pieces without the formation of cracks.
In addition, the method has the advantage that the viscosity of the liquid molten slag reduces. The addition of the alkali element-containing substance reduces the viscosity of the molten slag, due to the alkali atoms preventing or suppressing a polymerisation of the silicate constituents of the molten slag. Due to the alkali elements being monovalent, the prevention/suppression is stronger than that of elements having a higher valency.
The lower viscosity makes it easier for the dissolved gases to escape from the liquid. In addition, an improved supply to the casting die volume from the liquid phase can be achieved during the solidification process, so that a relatively thinner wall thickness of the moulded product can be achieved.
As the lowering of the solidification point increases the temperature difference between the actual process temperature of the molten slag and the solidification point, the lowering of the solidification point can also be used for significant energy recovery from the liquid slag.
Moreover, the invention makes it possible to form products by means of a continuous process, comparable to the possibilities in the steel industry.
In addition, the invention provides a method as described above, in which the alkali element is selected from potassium and sodium. These elements have the desired effect and do not adversely affect the metastable Ca and Mg components in the molten slag.
In an embodiment, the invention provides a method as described above, wherein the calcium silicate-containing molten slag is a steel slag or a thermal phosphorus slag containing less than 1% Na20.
In an embodiment, the invention provides a method as described above, wherein the liquid slag alloy contains between 1% and 5% alkali element oxide component, wherein the alkali element is selected from a group of at least one of sodium and potassium. Addition of such amounts to this composition results in a lowering of the solidification point in the order of magnitude of 200 to 300° (Celsius).
In an embodiment, the invention provides a method as described above, wherein the alkali element-containing substance is selected from a carbonate or a halogenide compound. Alkali carbonates decompose, during which process C02 is released which is finely distributed in the slag and can thus serve as a trigger for forming gas bubbles for gases dissolved in the slag, thereby assisting degassing. The use of alkali halogenide has the advantage that the halogenide can react with the metastable Ca and/or Mg components, in which case more stable Ca and/or Mg components are formed.
In an embodiment, the invention provides a method as described above, comprising the addition of a second additive comprising silicate compounds, wherein an amount of the second additive to be added depends on an amount of unstable reactive calcium and/or magnesium oxides, and wherein an active component of the silicate compounds to be added is not calcium or magnesium silicate and, in addition, fine-grained (preferably <100 micrometres).
This second additive serves to further stabilize the metastable Ca and Mg components in the slag in the form of a respective silicate compound.
In an embodiment, the invention provides a method as described above, wherein the second additive is an amorphous substance.
This type of substance needs less energy in order to pass to the liquid phase, unlike crystalline substances which require additional energy in order to break the crystal lattice. As a result thereof, the amorphous substance can become liquid more quickly and react with the metastable Ca and Mg components in the molten slag.
In an embodiment, the invention provides a method as described above, wherein the amorphous substance is fly ash, in particular carbon-containing fly ash.
It has been found that fly ash from coal-fired power stations is highly suitable for this application. Moreover, the carbon in the fly ash amplifies the degassing by the formation of carbon dioxide in the liquid slag alloy.
In an embodiment, the invention provides a method as described above, wherein the silicate compounds of the second additive do not comprise quartz. In this manner, the quartz content of the slag alloy is prevented from rising, and an increase of the thermal stress in the moulded product as a result of the 'quartz transition' at approximately 573 °C is prevented.
In an embodiment, the invention provides a method as described above, comprising withdrawing heat from the liquid slag alloy after the addition of at least the first additive and before casting.
As the slag has approximately the same temperature as the molten metal when leaving the furnace, and the melting point of the modified slag is much lower (approx. 1200 °C compared to approx. 1500 °C), excess heat can be withdrawn from the liquid slag without the slag alloy reaching the solidification range.
In an embodiment, the invention provides a method as described above, comprising lowering the temperature of the liquid slag alloy to a temperature which is
approximately 50" (Celsius) above the solidification point of the liquid slag alloy while withdrawing heat from the liquid slag alloy.
In an embodiment, the invention provides a method as described above, comprising actively mixing the liquid molten slag and the at least first additive during the addition of at least the first additive.
Mixing improves the alloying process of the molten slag to form the slag alloy.
In an embodiment, the invention provides a method as described above, comprising the addition of vibration energy to the liquid slag alloy and/or the liquid molten slag before casting it into the casting die.
The addition of vibrations improves the degassing of the liquid slag. In this case, the reduction of the viscosity by the addition of the first additive facilitates the result obtained by the vibrations.
In an embodiment, the invention provides a method as described above, wherein the liquid slag alloy is divided into several casting streams before casting.
This measure also has the advantage that degassing is improved further.
In an embodiment, the invention provides a method as described above, wherein, after casting into the casting die, the cooling rate in a range around 573 °C is adjusted to the amount of quartz present in the slag alloy.
By controlling the cooling rate, the occurrence of thermal stresses as a result of the quartz transition can be reduced due to stress relaxation.
In an embodiment, the invention comprises a method as described above, comprising granulating the slag alloy during casting.
The invention also relates to the above-described device, comprising an inlet for a liquid molten slag which originates from a production process of a molten material from ore in a furnace, wherein the inlet is connected to the furnace for receiving the liquid molten slag; an outlet for casting the received liquid molten slag into a casting die; a conveyor runner which extends from the inlet to the outlet for enabling the liquid molten slag to flow from the inlet to the outlet, wherein the device furthermore comprises an inlet for adding at least one additive to the received liquid molten slag in order to form a liquid slag alloy, wherein the conveyor runner is provided with one or more blades or guides for mixing the at least first additive and the flowing liquid slag alloy during use.
Further embodiments of the method or the device according to the present invention are described in the sub claims.
The invention will be described in more detail below with reference to a number of drawings which show some exemplary embodiments. The drawings are only intended for illustrative purposes and cannot be interpreted as a limitation of the inventive idea which is defined by the attached claims.
In the drawings:
Fig. 1 shows a process diagram of a method according to an embodiment of the invention;
Figs. 2a, 2b diagrammatically show a device according to an embodiment of the invention.
In the following figures, identical components are in each case referred to by the same reference numerals.
Fig. 1 shows a process diagram of a method of treating a molten slag which can be used in connection with a metallurgical process.
In said metallurgical processes, a liquid base material, often a liquid metal, is produced in a furnace at high temperatures from ore(s) and additives. Examples are processes for the production of steel and non-ferrous metals and thermal phosphorus production. The ore(s) is (are) the raw material which contains the base material to be recovered, such as iron ore, or a phosphorus-containing ore, a non-ferrous ore and additional components, such as for example limestone. During the production of the liquid base material, additive(s) are added to release or stabilize the base material from the ore. In addition to the liquid base material, these processes produce a by-product in the form of a molten slag which is formed from a reaction product of the secondary components of the ore and/or components of the additive(s).
The present invention relates to a method for treating and processing the molten slag. Fig. 1 shows a flow diagram of a process 100 for treating and processing the molten slag.
In a first step 101, the molten slag is separated from the liquid base material. Typically, the liquid base material together with the molten slag is situated in a furnace or reactor, where a process temperature prevails which is determined by the (metallurgical) process in order to release the base material.
In thermal processing of ore, such as steel production or thermal phosphorus production, the process temperature is approximately between 1500 and 1700 °C. When it is being separated, the molten slag therefore has a temperature which substantially corresponds to the process temperature in the thermal processing of ore. In a subsequent step 102, at least a first additive is added to the molten slag. An additive contains one or more alkali-containing components (elements or compounds) which have the property that they form an alloy using the separated liquid molten slag or that they react with the separated liquid slag, wherein the composition of the liquid slag alloy changes in such a manner that the solidification point or the solidification range temperature is lowered.
It is assumed that the invention provides that a eutectic or peritectic composition is obtained or at least a composition which has a lower melting point and, according to the phase theory, comes closer to a eutectic or peritectic composition than the composition of the separated molten slag.
In the case of steel production, the molten slag is a calcium silicate-containing residual product which is characterized by a high content of mineral components (mostly silicon
and aluminium compounds). In addition, the steel slag may also contain reactive metastable calcium and magnesium compounds.
For this type of molten slag, the first additive comprises an alkali element-containing substance, such as sodium, and/or potassium compounds. The addition of this element (these elements) ensures that the composition of the molten slag "moves" in the direction of a eutectic or peritectic point (range) which is known from phase diagrams and/or phase information for molten slag material.
According to the invention, after the addition of the first additive, the liquid slag alloy contains between 1% and 5% of sodium and/or potassium oxide compound (in % by weight) or has a composition range between approximately 1% and approximately 6% of sodium or potassium oxide, or between approximately 2% and approximately 4% of sodium or potassium oxide.
In this step, a second additive is optionally added for stabilizing the reactive calcium and/or magnesium compounds in the molten slag. This second additive contains silicate-containing substances which bond with the reactive calcium and magnesium compounds to form a stable calcium silicate and magnesium silicate, respectively. It will be clear that the composition of the separated liquid molten slag is determined before this alloying or reaction step. On the basis thereof, it can then be determined which amount of first additive and, if required, which amount of second additive is to be added.
Regarding the addition of calcium compounds, it should be noted that this is preferably only carried out if no reactive calcium or magnesium compounds are present in the molten slag and these themselves only form the stable phase in the molten slag or during the cooling down.
In a subsequent step 103, the additive(s) added in step 102 is (are) actively mixed with the molten slag in order to assist the alloying/reaction process. Mixing creates a liquid slag alloy from the molten slag.
Due to the composition of the slag being changed, the solidification point (or melting point) thereof will be changed (i.e. lowered). Starting from the abovementioned phase theory, the melting point is lowered in the direction of the minimum liquidus temperature which occurs at the eutecticum by "moving" to the eutectic point in the phase diagram. As a result thereof, the slag thus remains liquid down to relatively low temperatures than without alloying or reaction step 102.
For a steel slag, this results in a lowering of the temperature from approx. 1500 to approx. 1200 °C.
Incidentally, the alloying of the slag as described above has the result that the solidification range is reduced in relative terms (with a modified, but non-eutectic composition) and the solidification range only takes place at the relatively lower temperature than with the separated liquid slag. The 'two-phase' range in which the slag consists of a solid and a liquid component is reduced by the alloying step, moves to a lower temperature, which increases the castability of the slag alloy.
Those skilled in the art will realize that, depending on the composition, the phase systems may be binary, ternary, quaternary or of an even higher order.
In order to assist the desired reactions, if possible the first and, if necessary, the second additive in an embodiment is an amorphous substance: compared to crystalline substances, a substance having an amorphous structure has the advantage that no transformation of the crystal structure to the liquid phase has to take place. As a result thereof, mixing or dissolution of the additive(s) is facilitated and accelerated in relative terms.
During or after mixing, the method comprises that the slag alloy is subjected to a degassing treatment.
Degassing may take place by shaking the slag alloy, in which case gas bubbles can escape from the slag alloy. With this form of degassing, the amount of residual gas in the slag alloy decreases, so that an improved solidification structure of the slag is achieved. This step is also advantageous in order to reduce the build-up of internal stress in the solidified slag by any gas which may be present.
As has already been described above, the degassing is also improved by the added additive(s) which, inter alia, result in a lower viscosity.
Subsequently, in a step 104, heat is actively withdrawn from the slag alloy, for example by means of a heat-exchanging element. As has already been explained above, the formation of the slag alloy lowers the melting/solidification point (or the
melting/solidification range). As the separated slag is released at a relatively high temperature compared to the melting/solidification point of the slag alloy, there is an excess of heat in the liquid phase of the slag alloy. This excess of heat can be withdrawn. The energy content thereof can be used elsewhere. It should be noted that the energy recovery 104 can also take place (at least partly) simultaneously with the
addition phase 102 and/or the mixing phase 103, depending on the actual temperature of the molten slag.
In this step, the temperature of the slag alloy can be lowered to about 50° (degrees Celsius) above the melting/solidification point (or the temperature of the start of solidification). Due to the reduced viscosity of the slag alloy, the liquidity is sufficient at this point in time for carrying out a casting process.
After the last step 104, the process diagram comprises two alternatives 105 - 107; 108 - 1 10 for the further treatment of the cooled-down liquid slag alloy.
In the first alternative 105 - 107, the liquid slag alloy is cast into a casting die in step 105. In an embodiment, this step comprises dividing the slag alloy into a number (more than one) casting streams. This has the advantage that the exchange of gases from the slag alloy to the atmosphere is improved.
In a subsequent step 106, the slag alloy in the casting die solidifies and cools down. Due to the lowered viscosity, a thinner wall thickness and higher form definition of the moulded product is possible than with a steel slag from the prior art.
In a further embodiment, there is an amount of molten slag which has already solidified in the casting die in the form of a stack of pieces or granules between which there are spaces. The liquid molten slag is cast thereon and, due to its low viscosity, fills the spaces between the pieces or granules. In addition, this reduces the wall thickness of the melt in the mould, so that in addition fewer thermal stresses will occur. The pieces should preferably have the same composition as the melt in order to obtain an end product which is as homogenous as possible. Due to the fact that a part of the mass in the casting die has already solidified, the total shrinkage in the casting die volume resulting from the solidification of the liquid material which is added will be relatively low. In this way, it is possible to produce a product with a reduced degree of thermal stress.
In an embodiment, when quartz is present in the slag alloy, the cooling down is controlled in such a manner that the region of the so-called quartz transition (that is to say the phase transformation of quartz at approx. 573 °C) is passed through at a low cooling rate. This phase transformation is accompanied by a change in volume which may generate a mechanical stress in the cast material. By controlling the cooling down process (cooling rate) over time, it is possible to limit the internal stress due to thermal expansion and the quartz transition by time-dependent stress relaxation.
Finally, in step 107, a moulded product is obtained as end product. After step 107, the process diagram ends with 11 1 in this first variant.
In a second variant of the process diagram, a second alternative 108 - 1 10 for the further treatment of the liquid slag alloy follows after the step 104 of cooling down to close to the eutectic point.
In the second alternative 108 - 110, the liquid slag alloy is cast and granulated in step 108, that is to say the solidified slag alloy material consists of granular material, granules.
The granules are collected and held in a storage volume.
In a subsequent step 109 which may, at least in time, partly coincide with the granulating process 108, the granules are cooled down.
Optionally, step 109 is used to withdraw heat (forced cooling) from the granules for the purpose of, for example, energy recovery. This forced cooling is advantageously possible because, although any increased thermal and/or internal stress resulting from the forced cooling may lead to the formation of cracks and breakage of the solidified slag material, in granules cracks in and/or crumbling of the material is permissible.
In step 110, the cooled down granules are collected as an end product.
After step 110, the process diagram ends with step 112 in this second variant.
Figs. 2a, 2b diagrammatically show a device according to an embodiment of the invention.
The device 200 is configured for use in carrying out the method 100 according to the invention.
The device 200 comprises a tubular body 201. At one end, the tubular body 201 is provided with an inlet 202. The inlet 202 is configured to receive the liquid molten slag from the furnace. To this end, the inlet may be coupled to an outlet of the furnace or may be provided with, for example, an opening where a casting stream 300 from the furnace can be introduced into the tubular body. At the opposite end, the tubular body is provided with an outlet 203.
In an embodiment, the tubular body is provided with an insulating cladding, for example in the form of a refractory layer.
In use, the tubular body is arranged at an angle in such a way that, compared to ground level, the inlet is situated above the outlet.
Furthermore, the inlet 202 is configured to receive an additive stream 301 to form the slag alloy with the molten slag material.
On an internal wall 201a of the tubular body 201, a number of mixing blades or ridges 205 are arranged which are configured, in use, to disturb a flow of the combination of molten slag 300 and additives 301 flowing past, resulting in an improvement in the mixing of the slag alloy and the additives and in an improvement in the degassing. In this case, the tubular body 201 has a length which is such that, during the passage time of the combination of flowing molten slag 300 and additives 301 , the formation of the slag alloy (that is to say the formation of the mainly eutectic or peritectic composition) is achieved/completed. The length may also depend on a distance to be bridged between the inlet location from the furnace and a processing location of the slag alloy.
In an embodiment, the tubular body has a diameter between approximately 20 and approximately 40 cm.
In an embodiment, the device 200 is also provided with a vibrating or shaking installation 206, 207 which is configured to supply vibration energy to the tubular body 201. In connection with the alloying or reaction process in the device, the supply of vibrations makes it easier for the gas bubbles present in the slag alloy to escape, as a result of which the structure of the solidified slag alloy has fewer large inclusions and the porosity can be controlled or reduced. It should be noted that pores of a similar size, such as are found in, for example, sand lime and (foamed) concrete are usually acceptable in the moulded slag product.
The outlet 203 for the discharge of the slag alloy is situated at the end of the tubular body 201. A heat-exchanging element 208 is connected to the outlet 203 and is configured to collect the liquid slag alloy after it has passed through the tubular body 201 and to withdraw heat from the slag alloy which is in contact with the heat- exchanging element.
The heat-exchanging element comprises a heat-conducting plate 208 which is provided with ducts 209 on the inside. A liquid medium can be passed through the ducts 209 in order to withdraw heat from the heat-conducting plate 208.
The heat-exchanging element is controlled in such a manner that the liquid slag alloy is cooled to approximately 50° (Celsius) above the melting point of the slag alloy. The heat which has been withdrawn can be used as a source of heat in other locations, for
example within the installation(s) where this process is being carried out, and it is also possible to apply energy-recovery techniques to the heat (stream) which has been withdrawn.
Fig. 2b shows a cross section of the tubular body at the location of the line Ilb-IIb in Fig. 2a. The tubular body 201 comprises an insulating cladding which is situated on the inner wall of the tubular body or at least on the part of the inner wall with which the liquid slag could come into contact. Furthermore, one of the mixing blades 205 is visible in the bottom section (which is situated at a lower level) of the tubular body . In an embodiment, the mixing blade 205 is configured as a body which tapers from the wall, possibly as a plate-shaped or fin-shaped body.
It will be clear to those skilled in the art that other forms of mixing blade are also possible, such as ridges or rod-shaped projections on the bottom section of the tubular body. It is also possible for the tubular body to be configured in the form of a runner. Further features, possible uses and advantages of the invention will become clear from the following description of exemplary embodiments of the invention which are illustrated in the figures of the drawing. In these, all the features which have been described or illustrated are in themselves or in any combination the subject matter of the invention, irrespective of whether they are summarized in the claims or referred back to and likewise irrespective of how they are phrased or represented in the description or in the drawing, respectively.
The device according to the invention can also be used in a method in which a silicate- containing additive is added to the molten slag.
The aim of this method is to transform the metastable or reactive calcium and/or magnesium compounds into stable components in the molten slag. The method relates to a treatment of a calcium silicate-containing molten slag in a metallurgical process, comprising:
- producing a molten material from ore in a furnace, wherein a liquid molten slag is formed on the surface of the molten material;
- separating the liquid molten slag from the molten material;
- casting the separated liquid molten slag into a casting die;
- cooling down the molten slag in the casting die;
wherein the method furthermore comprises:
prior to casting, adding at least an additive which comprises silicate compounds,
wherein an amount of this additive to be added is dependent on an amount of unstable reactive calcium and/or magnesium oxides in the molten slag, and wherein an active component of the silicate compounds to be added is not calcium or magnesium silicate. By means of this method and the application of the device according to the invention, the quality of the molten slag is improved and the stability of the product moulded therefrom is improved.
Claims
1. Method for treating a calcium silicate-containing molten slag in a metallurgical process,
comprising:
- producing a molten material from ore in a furnace, wherein a liquid molten slag is formed on the surface of the molten material;
- separating the liquid molten slag from the molten material;
- casting the separated liquid molten slag into a casting die;
- cooling down the molten slag in the casting die;
wherein the method furthermore comprises:
prior to casting, adding at least a first additive which comprises at least one substance containing an alkali element to the separated liquid molten slag in order to form a liquid slag alloy for reducing a solidification point of the liquid slag alloy with respect to a solidification point of the molten slag,
wherein the liquid slag alloy contains between approximately 1 and approximately 6% of alkali element oxide component, and the alkali element is selected from a group including at least one of sodium and potassium.
2. Method according to Claim 1, wherein the alkali element is selected from potassium, and sodium.
3. Method according to Claim 1 or 2, wherein the calcium silicate-containing molten slag is a steel slag or a thermal phosphorus slag containing less than 1% Na20.
4. Method according to Claim 2, wherein the alkali element-containing substance is selected from a carbonate and a halogenide compound.
5. Method according to one of the preceding claims, comprising the addition of a second additive comprising silicate compounds, wherein an amount of the second additive to be added depends on an amount of unstable reactive calcium and/or magnesium oxides, and wherein an active component of the silicate compounds to be added is not calcium or magnesium silicate.
6. Method according to Claim 5, wherein the second additive is an amorphous substance.
7. Method according to Claim 5, wherein the amorphous substance is a carbon- containing fly ash.
8. Method according to Claim 5, wherein the silicate compounds of the second additive do not comprise quartz.
9. Method according to one of the preceding claims, comprising
withdrawing heat from the liquid slag alloy after the addition of at least the first additive and before casting.
10. Method according to Claim 9, comprising lowering the temperature of the liquid slag alloy to a temperature which is approximately 50°C above the solidification point of the liquid slag alloy while withdrawing heat from the liquid slag alloy
1 1. Method according to one of the preceding claims, comprising actively mixing the liquid molten slag and the at least first additive during the addition of at least the first additive.
12. Method according to one of the preceding claims, comprising the addition of vibration energy to the liquid slag alloy and/or the liquid molten slag before casting it into the casting die.
13. Method according to one of the preceding claims, wherein the liquid slag alloy is divided into several casting streams before casting.
14. Method according to one of the preceding claims wherein, after casting into the casting die, the cooling rate in a range around 573 °C is adjusted to the amount of quartz present in the slag alloy.
15. Method according to one of the preceding Claims 1 - 13, comprising granulating the slag alloy during casting.
16. Device for use in the treatment of a molten slag in a metallurgical process according to one of the preceding Claims 1 - 14,
comprising:
- an inlet for a liquid molten slag which originates from a production process of a molten material from ore in a furnace, wherein the inlet is connected to the furnace for receiving the liquid molten slag;
- an outlet for casting the received liquid molten slag into a casting die;
- a conveyor runner which extends from the inlet to the outlet for enabling the liquid molten slag to flow from the inlet to the outlet
wherein the device furthermore comprises:
an inlet for adding at least a first additive to the received liquid molten slag in order to form a liquid slag alloy,
wherein the conveyor runner is provided with one or more blades or guides for mixing the at least first additive and the flowing liquid molten slag during use,
furthermore comprising one or more vibrating elements which are connected to at least the conveyor runner for supplying vibration energy thereto.
17. Device according to Claim 16 , wherein the outlet is provided with a cooling cone for withdrawing heat from the liquid slag alloy or wherein the conveyor runner is provided, along a part of its length, on the side of the outlet with a cooling wall for withdrawing heat.
18. Device according to Claim 17, wherein the cooling cone and/or cooling wall comprises a heat-exchanging element in a contact wall of the cooling cone and/or cooling wall for the liquid slag alloy.
19. Device according to Claim 17 or 18, wherein the outlet is provided with an outlet piece for separating the stream of liquid slag alloy into a number of casting streams.
20. Device according to one of Claims 16 - 19, wherein the conveyor runner is a tubular body.
21. Method for treating a calcium silicate-containing molten slag in a metallurgical process,
comprising:
- producing a molten material from ore in a furnace, wherein a liquid molten slag is formed on the surface of the molten material;
- separating the liquid molten slag from the molten material;
- casting the separated liquid molten slag into a casting die;
- cooling down the molten slag in the casting die;
wherein the method furthermore comprises:
prior to casting, adding at least one additive which comprises silicate compounds, wherein an amount of this additive to be added depends on an amount of unstable reactive calcium and/or magnesium oxides in the molten slag, and wherein an active component of the silicate compounds to be added is not calcium or magnesium silicate.
22. Method according to Claim 21, wherein the additive is an amorphous substance.
23. Method according to Claim 22, wherein the amorphous substance is a carbon- containing fly ash.
24. Method according to Claim 21, wherein the silicate compounds of the additive do not comprise quartz.
25. Device according to one of Claims 16 - 20 for use in a method according to one of Claims 1 - 15 or a method according to one of Claims 21 - 24.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| NL2007190A NL2007190C2 (en) | 2011-07-28 | 2011-07-28 | METHOD AND APPARATUS FOR TREATMENT OF A MELTING SLIP |
| PCT/NL2012/050536 WO2013015690A1 (en) | 2011-07-28 | 2012-07-26 | Method and device for treating a molten slag |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| EP2737091A1 true EP2737091A1 (en) | 2014-06-04 |
Family
ID=46727534
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP12750856.2A Withdrawn EP2737091A1 (en) | 2011-07-28 | 2012-07-26 | Method and device for treating a molten slag |
Country Status (3)
| Country | Link |
|---|---|
| EP (1) | EP2737091A1 (en) |
| NL (1) | NL2007190C2 (en) |
| WO (1) | WO2013015690A1 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106636498B (en) * | 2016-11-18 | 2018-11-30 | 重庆科技学院 | A kind of method of resource utilization flyash |
Family Cites Families (15)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| BE639369A (en) | 1962-10-30 | |||
| DE2838679A1 (en) * | 1978-09-05 | 1980-03-13 | Ssab Svenskt Stal Ab | Granulation of molten material, esp. blast furnace slag - where stream of solid particles is fed into molten stream of slag to form granulate suitable for mfg. rock wool etc. |
| FR2506331A1 (en) * | 1981-05-22 | 1982-11-26 | Siderurgie Fse Inst Rech | PROCESS FOR THE TREATMENT OF DAIRY PHOSPHIDES |
| US5187126A (en) * | 1988-07-29 | 1993-02-16 | Nippon Chemical Industrial Co., Ltd. | Slag treatment material |
| JPH06329450A (en) | 1993-05-21 | 1994-11-29 | Nippon Steel Corp | Production of slag low in expansion coefficient |
| US5720835A (en) | 1995-02-08 | 1998-02-24 | Futuristic Tile L.L.C. | Decorative construction material and methods of its production |
| NL1003885C2 (en) | 1996-08-27 | 1998-03-03 | Hoogovens Tech Services | Gutter for a hot melt and gutter system. |
| US6311522B1 (en) | 1999-07-13 | 2001-11-06 | Slaytech Inc. | Process for casting and forming slag products |
| CA2278099C (en) | 1999-07-13 | 2003-09-16 | Slaytech Inc. | Process for casting and forming slag products |
| JP4676829B2 (en) * | 2005-07-12 | 2011-04-27 | 新日本製鐵株式会社 | Steelmaking slag treatment method |
| RU2297396C1 (en) | 2005-11-28 | 2007-04-20 | Общество с ограниченной ответственностью "Огнезащита" | Method of production of the melt from the rocks and the melt from the scrap of the mineral wool production and the device for the method realization |
| GB2437796B (en) | 2006-05-05 | 2011-08-03 | John William Carson | Improved blast furnace slag |
| JP2008120607A (en) * | 2006-11-08 | 2008-05-29 | Jfe Steel Kk | Method for processing steel slag |
| WO2009089906A1 (en) * | 2008-01-15 | 2009-07-23 | Recoval Belgium | Process for producing mortar or concrete |
| JP2009270132A (en) | 2008-04-30 | 2009-11-19 | Sanyo Special Steel Co Ltd | Method for producing steelmaking slag with high swelling stability |
-
2011
- 2011-07-28 NL NL2007190A patent/NL2007190C2/en not_active IP Right Cessation
-
2012
- 2012-07-26 WO PCT/NL2012/050536 patent/WO2013015690A1/en active Application Filing
- 2012-07-26 EP EP12750856.2A patent/EP2737091A1/en not_active Withdrawn
Non-Patent Citations (1)
| Title |
|---|
| See references of WO2013015690A1 * |
Also Published As
| Publication number | Publication date |
|---|---|
| WO2013015690A1 (en) | 2013-01-31 |
| NL2007190C2 (en) | 2013-01-29 |
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