AU677632B2 - A slag defoaming composite - Google Patents
A slag defoaming compositeInfo
- Publication number
- AU677632B2 AU677632B2 AU59961/94A AU5996194A AU677632B2 AU 677632 B2 AU677632 B2 AU 677632B2 AU 59961/94 A AU59961/94 A AU 59961/94A AU 5996194 A AU5996194 A AU 5996194A AU 677632 B2 AU677632 B2 AU 677632B2
- Authority
- AU
- Australia
- Prior art keywords
- composite
- slag
- range
- defoaming
- slag defoaming
- 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.)
- Expired
Links
- 239000002131 composite material Substances 0.000 title claims description 48
- 239000002893 slag Substances 0.000 title claims description 45
- 239000000463 material Substances 0.000 claims description 17
- 229910052782 aluminium Inorganic materials 0.000 claims description 15
- 229910052799 carbon Inorganic materials 0.000 claims description 15
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 14
- 239000004411 aluminium Substances 0.000 claims description 13
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims description 13
- 239000011230 binding agent Substances 0.000 claims description 12
- 239000000314 lubricant Substances 0.000 claims description 10
- 239000001913 cellulose Substances 0.000 claims description 8
- 229920002678 cellulose Polymers 0.000 claims description 8
- 238000004519 manufacturing process Methods 0.000 claims description 8
- 239000004115 Sodium Silicate Substances 0.000 claims description 7
- NTHWMYGWWRZVTN-UHFFFAOYSA-N sodium silicate Chemical group [Na+].[Na+].[O-][Si]([O-])=O NTHWMYGWWRZVTN-UHFFFAOYSA-N 0.000 claims description 7
- 229910052911 sodium silicate Inorganic materials 0.000 claims description 7
- 235000008733 Citrus aurantifolia Nutrition 0.000 claims description 6
- 235000011941 Tilia x europaea Nutrition 0.000 claims description 6
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 claims description 6
- CJZGTCYPCWQAJB-UHFFFAOYSA-L calcium stearate Chemical compound [Ca+2].CCCCCCCCCCCCCCCCCC([O-])=O.CCCCCCCCCCCCCCCCCC([O-])=O CJZGTCYPCWQAJB-UHFFFAOYSA-L 0.000 claims description 6
- 235000013539 calcium stearate Nutrition 0.000 claims description 6
- 239000008116 calcium stearate Substances 0.000 claims description 6
- 239000004571 lime Substances 0.000 claims description 6
- 239000002994 raw material Substances 0.000 claims description 6
- BPQQTUXANYXVAA-UHFFFAOYSA-N Orthosilicate Chemical compound [O-][Si]([O-])([O-])[O-] BPQQTUXANYXVAA-UHFFFAOYSA-N 0.000 claims description 5
- 239000008187 granular material Substances 0.000 claims description 5
- 239000008188 pellet Substances 0.000 claims description 4
- 239000004927 clay Substances 0.000 claims description 3
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 claims description 2
- 229910052791 calcium Inorganic materials 0.000 claims description 2
- 239000011575 calcium Substances 0.000 claims description 2
- QIQXTHQIDYTFRH-UHFFFAOYSA-N octadecanoic acid Chemical compound CCCCCCCCCCCCCCCCCC(O)=O QIQXTHQIDYTFRH-UHFFFAOYSA-N 0.000 claims description 2
- 239000000203 mixture Substances 0.000 description 17
- 239000004484 Briquette Substances 0.000 description 13
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 10
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 9
- 229910000831 Steel Inorganic materials 0.000 description 9
- 239000010959 steel Substances 0.000 description 9
- 239000000404 calcium aluminium silicate Substances 0.000 description 7
- 235000012215 calcium aluminium silicate Nutrition 0.000 description 7
- WNCYAPRTYDMSFP-UHFFFAOYSA-N calcium aluminosilicate Chemical compound [Al+3].[Al+3].[Ca+2].[O-][Si]([O-])=O.[O-][Si]([O-])=O.[O-][Si]([O-])=O.[O-][Si]([O-])=O WNCYAPRTYDMSFP-UHFFFAOYSA-N 0.000 description 7
- 229940078583 calcium aluminosilicate Drugs 0.000 description 7
- 239000004615 ingredient Substances 0.000 description 6
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 5
- 229910052742 iron Inorganic materials 0.000 description 5
- 238000002156 mixing Methods 0.000 description 5
- 229910052760 oxygen Inorganic materials 0.000 description 5
- 239000001301 oxygen Substances 0.000 description 5
- 238000000034 method Methods 0.000 description 4
- 239000000843 powder Substances 0.000 description 4
- 239000000377 silicon dioxide Substances 0.000 description 4
- 238000006243 chemical reaction Methods 0.000 description 3
- 238000005187 foaming Methods 0.000 description 3
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 2
- 230000009471 action Effects 0.000 description 2
- 239000000654 additive Substances 0.000 description 2
- 230000008901 benefit Effects 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 239000007789 gas Substances 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- 230000009467 reduction Effects 0.000 description 2
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 1
- 229920001131 Pulp (paper) Polymers 0.000 description 1
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 1
- 230000002745 absorbent Effects 0.000 description 1
- 239000002250 absorbent Substances 0.000 description 1
- 239000002518 antifoaming agent Substances 0.000 description 1
- 238000007664 blowing Methods 0.000 description 1
- 229910002092 carbon dioxide Inorganic materials 0.000 description 1
- 239000001569 carbon dioxide Substances 0.000 description 1
- 229910002091 carbon monoxide Inorganic materials 0.000 description 1
- 238000002485 combustion reaction Methods 0.000 description 1
- 238000007906 compression Methods 0.000 description 1
- 230000006835 compression Effects 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 239000006185 dispersion Substances 0.000 description 1
- 239000000428 dust Substances 0.000 description 1
- -1 eg. Substances 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- 239000006260 foam Substances 0.000 description 1
- 238000009472 formulation Methods 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- WPBNNNQJVZRUHP-UHFFFAOYSA-L manganese(2+);methyl n-[[2-(methoxycarbonylcarbamothioylamino)phenyl]carbamothioyl]carbamate;n-[2-(sulfidocarbothioylamino)ethyl]carbamodithioate Chemical compound [Mn+2].[S-]C(=S)NCCNC([S-])=S.COC(=O)NC(=S)NC1=CC=CC=C1NC(=S)NC(=O)OC WPBNNNQJVZRUHP-UHFFFAOYSA-L 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 239000003921 oil Substances 0.000 description 1
- 239000010893 paper waste Substances 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 230000000149 penetrating effect Effects 0.000 description 1
- 230000009257 reactivity Effects 0.000 description 1
- 150000004760 silicates Chemical class 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- 239000010703 silicon Substances 0.000 description 1
- 238000009628 steelmaking Methods 0.000 description 1
- 239000002023 wood Substances 0.000 description 1
Landscapes
- Curing Cements, Concrete, And Artificial Stone (AREA)
Description
A SLAG DEFOAMING COMPOSITE
BACKGROUND OF THE INVENTION
This invention relates to a slag defoaming composite for example, for use in steel manufacture, which may preferably be in briquette or pellet form. However, the invention is not restricted to steel manufacture and may be suitable in a number of applications where the defoaming of slag or the reduction of oxides to the metallic state is required.
During steel manufacture, iron from a blast furnace is converted to steel by placing the iron in a basic oxygen furnace. The quantity of iron can vary. Typically, it is about 200 tonnes. Oxygen is blown into the iron by an oxygen lance and the removal of impurities such as carbon, silicon, manganese, etc., converts the iron to steel. During the blowing process the slag on top of the steel foams to varying degrees dependent on the type of steel being produced. This foaming of the slag is undesirable as it extends the steel making time and therefore results in additional energy and labour costs.
It is known that elements such as carbon or aluminium exothermically react with slag, thereby raising the temperature of the slag, reducing viscosity and allowing gases such as carbon monoxide and carbon dioxide to be released from this more fluid liquid and hence reduce or stop the foaming action.
In the past products, such as tightly wound newspaper, timber, oil or tar derivatives, waste paper pulp, aluminium powder and pure aluminium metal, have been added to the slag in order to reduce foaming.
A number of disadvantages are associated with such
known defoaming products. Firstly, the low density of some of these products does not allow them to penetrate the slag, and hence the defoaming action is inefficient. Secondly, when utilising ύh'- defoaming additives the material is stored in a hopper above the blast furnace where conditions are hot, and sparks and lime dust are present. Under such conditions a number of the known defoaming additives can spontaneously combust either because of their carbonacious content or because of lime powder settling on the product, becoming moist and reacting exothermically with the product.
SUMMARY OF THE INVENTION
The present invention seeks to ameliorate the abovementioned disadvantages and provide an efficient and rapid defoaming agent.
In one broad form, the present invention provides a slag defoaming composite, comprising: a carbon source; a source of exothermic material, such as aluminium; a dense insert granular material, such as calcium alumina silicate; and a binder, optionally provided; characterised in that, said composite is selected to have a density sufficient to penetrate the slag layer during processing.
Most preferably, said composite is manufactured in the form of briquettes pellets, and/or the like.
In a preferred embodiment, said slag defoaming composite is substantially non-combustible.
Perhaps most preferably, the density of said composite is selected to be in the range of 1.0 to 2.6 g/cc.
In a preferred form of the invention, the slag defoaming composite comprises: a carbon source which yields a final carbon content cf the composite in the range of 3 to 50% w/w; a source of aluminium which yields a final aluminium content of the composite within the range of 5 to 60% w/w; a calcium alumino silicate or a similar dense inert granular material within the range of 10 to 50% w/w; and a binder within the range of 0 to 20% w/w.
Most preferably, said binder is sodium silicate or similar silicate derivatives, be they organic or inorganic, or clay, lime, or the like.
Preferably, the composite further comprises a lubricant material.
Most preferably, said lubricant material is a stearate, such as calcium stearate.
Preferably, said lubricant material is provided within the range of 0 to 2% w/w.
Preferably, said composite further comprises a slag fluidiser.
Most preferably, said slag fluidiser is provided in the range of 0 to 30% w/w.
In another form, the composite further comprises: cellulose based raw material; and flame retardent.
Preferably, said cellulose based raw material is provided in the range of 3 to 30% w/w.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
The slag defoaming composite of the present invention, and the process to manufacture same in briquette form, will now be described by way of example, describing preferred but non-limiting embodiments of the invention.
In one form typical ingredients include fine granular premelted calcium alumino silicate, fine powder alumina/aluminium, a silica/carbon fine powder admixture, sodium silicate binder and calcium stearate lubricant. The ingredients are mixed together, and then compressed, ideally to a briquette form. Details of the ingredients are as follows, with a suitable composition range for the slag defoaming composite being listed in Example 1, whilst Example 2 provides an example of a typical specific composition.
EXAMPLE 1
COMPOSITION RANGE FOR ONE FORM w/w
Calcium Alumino Silicate 10-50% Alumina/Aluminium admixture 10-50% (5-60% Al) Silica/Carbon admixture 10-50% (3-15% C) Sodium silicate 0-20% Calcium stearate lubricant 0-2%
EXAMPLE 2
COMPOSITION (TYPICAL BRIQUETTE FORMULATION)
w/w
Calcium Alumino Silicate 22.7 (adjusts the density)
Alumina/Aluminium admixture 45 (14% Al)
Fine Silica/Carbon admixture 22.7 (6.8% Carbon) (15.9% Si02)
Sodium silicate 9.5% Calcium stearate lubricant
0.2kg/150kg mix 0.133-
The calcium alumino silicate, or like material has a very important role in the manufacturing of the briquette. It is a non-absorbent/inert material which coarsens the mix and thus adjusts the particle size distribution which allows for the briquetting of the mixture.
The binder material is important to bind the various components together. A silicate, such as sodium silicate or other similar silicate may be used, or alternatively, materials such as clay or lime, which have a binding effect may be used. Depending, however, on the other components of the composite, a specialised binder material may not need to be added. That is, the other components of the composite may have a binding effect on the ingredients of the composite, such that a specialised binder material is unnecessary.
Various methods may be used to manufacture a suitable briquette - an example of which is now described. The ingredients such as calcium alumino silicate, alumina/aluminium and the carbon silica mixture are firstly weighed separately and added into a mixing mill. They are dry mixed typically for three to five minutes. Sodium silicate, which acts as a binder, is finely sprayed into the mix while the mill is blending and this proceeds for a further six to eight minutes. In the last one minute of mixing, the calcium stearate lubricant is added and mixed in. The long mixing time yields a relatively dry mix characterised by good flowability which is essential in the manufacturing process.
It is important when blending the mix that it should be able to flow well, otherwise the size and density of the briquette may be difficult to control. The mixture should also be free of lumps.
Optionally, slag fluidiser, cellulose based raw materials and flame retardents may also be included.
In an optional embodiment of the invention, the composite may contain carbon in the range of 3 to 50% w/w. s ag fluidiser in the range of 0 to 30% w/w, and cellulose based raw materials, such as wood chips in the range of 3 to 30%. When the composite contains cellulose, flame retardent is added to prevent auto combustion in the hopper above the BOF.
The mixture is then formed into a briquette. A preferred method of forming the briquette is to place the low moisture mixture in a hydraulic press and then to compress it to a pressure in excess of 20 tonnes per square inch to form a hard briquette with compression strength above 1000 kPa. A typical size for cylindrically shaped briquettes may be in the range of 65-75 mm in diameter and a 35-50mm in height.
The typical density for the briquette in Example 2 would be in the vicinity of 2.4 g/cc; however densities in the range of 1.0 to 2.6 are quite acceptable. The density can generally be adjusted by varying the quantity of the dense inert granular material, eg., calcium alumino silicate present, the content of cellulose based-material or other variations in composition or processing.
The briquettes are manufactured with different densities to suit different needs. For example, for steels with very viscous slag, briquettes of high density are required. Also the defoaming composite could be in various briquette shapes and sizes as well as in pellet and other forms. For example, the shape could be cylindrical, half cylindrical, rectangular, certain shapes being more preferable for transportation purposes, etc., as will be understood to persons skilled in the art.
The slag defoaming composite as described herein has the advantage that the density of a slag defoaming composite
- 1 - briquette can be chosen so as to penetrate the surface of the slag, but not sink into the steel. Being suspended within the slag layer results in an efficient exothermic reaction therefore improving the release of gases and reduction of slag viscosity which is desired in order to achieve defoaming. As mentioned this.typical density range is in the vicinity of 1.0 to 2.6 g/cc.
Variation in the reactivity of the composite is controllable by variation in the composition thereof.
Also, the very fine division of the ingredients used causes good dispersion of reactive elements and thus promotes a highly exothermic reaction to thin the slag.
The size, shape and hardness of the briquettes allows them to be handled and placed into hoppers which are held above the basic oxygen furnace without breakage, and to freefall into the furnace without loss of product or thermal reaction, before penetrating the slag.
A final important advantage of the slag defoaming composite is that it will not combust when stored in a hopper above the basic oxygen furnace and nor will it react exothermically with powdered lime which may enter into the hopper containing the composite.
As will be appreciated by persons skilled in the art, numerous variations and modifications will become apparent to the specific embodiments hereinbefore described with reference to the examples. All such variations and modifications should be considered to fall within the scope of the invention as hereinbefore described and as hereinafter claimed.
Claims (15)
1. A slag defoaming composite, comprising: a carbon source; a source of exothermic material, such as aluminium; a dense insert granular material, such as calcium alumina silicate; and a binder, optionally provided; characterised in that, said composite is selected to have a density sufficient to penetrate the slag layer during processing.
2. A slag defoaming composite as claimed in claim 1, wherein said composite is manufactured in the form of briquettes, pellets, and/or the like.
3. A slag defoaming composite as claimed in any one of claims 1 to 2, wherein said composite is substantially non-combustible.
4. A slag defoaming composite as claimed in any one of claims 1 to 3, wherein said density of said composite is selected to be in the range of 1.0 to 2.6 g/cc.
5. A slag defoaming composite as claimed in any one of claims 1 to 4, comprising: a carbon source which yields a carbon content of the composite within the range of 3 to 50% w/w; a source of exothermic material such as aluminium which yields aluminium content of the composite within the range of 5 to 60% w/w; a dense inert granular material within the range of 10 to 50% w/w; and a binder optionally provided within the range of 0 to 20% w/w.
6. A slag defoaming composite as claimed in claim 5, wherein said binder is sodium silicate, or a similar silicate binder be it organic or inorganic, or clay, lime, or the like.
7. A slag defoaming composite as claimed in any one of claims 1 to 6, further comprising a lubricant material.
8. A slag defoaming composite as claimed in claim 7, wherein said lubricant material is a stearate, such as calcium stearate.
9. A slag defoaming composite as claimed in claims 7 or 8, wherein said lubricant material is provided with the range of 0 to 2% w/w.
10. A slag defoaming composite as claimed in any one of claims 1 to 9, further comprising slag fluidiser.
11. A slag defoaming composite as claimed in claim 10, wherein said slag fluidiser is provided in the range of 0 to 30% w/w.
12. A slag defoaming composite as claimed in any one of claims 1 to 11, further comprising: cellulose based raw material; and flame retardent.
13. A slag defoaming composite as claimed in claim 12, wherein said cellulose based raw material is provided in the range of 3 to 30% w/w.
14. A slag defoaming composite, substantially as herein described.
15. A method of manufacturing/using a slag defoaming composite, substantially as herein described.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| AU59961/94A AU677632B2 (en) | 1993-02-05 | 1994-02-04 | A slag defoaming composite |
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| AUPL7152 | 1993-02-05 | ||
| AUPL715293 | 1993-02-05 | ||
| AU59961/94A AU677632B2 (en) | 1993-02-05 | 1994-02-04 | A slag defoaming composite |
| PCT/AU1994/000049 WO1994018347A1 (en) | 1993-02-05 | 1994-02-04 | A slag defoaming composite |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| AU5996194A AU5996194A (en) | 1994-08-29 |
| AU677632B2 true AU677632B2 (en) | 1997-05-01 |
Family
ID=25632656
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| AU59961/94A Expired AU677632B2 (en) | 1993-02-05 | 1994-02-04 | A slag defoaming composite |
Country Status (1)
| Country | Link |
|---|---|
| AU (1) | AU677632B2 (en) |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH06196021A (en) * | 1991-06-12 | 1994-07-15 | Central Glass Co Ltd | High dielectric constant high molecular material |
-
1994
- 1994-02-04 AU AU59961/94A patent/AU677632B2/en not_active Expired
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH06196021A (en) * | 1991-06-12 | 1994-07-15 | Central Glass Co Ltd | High dielectric constant high molecular material |
Also Published As
| Publication number | Publication date |
|---|---|
| AU5996194A (en) | 1994-08-29 |
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