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US 2015/0175488 A1Published application
Flame-retardant product and use thereof
AssigneeRefratechnik Holding GmbH
InventorHelge Jansen
Life of this patent
Estimating the term…
Abstract
A flame-retardant batch, and the use thereof, primarily contains—at least 30% by weight of a coarse-grain olivine raw material with a forsterite content of, e.g. at least 70% by weight and having grain sizes of, e.g. 100% by weight over 0.1 mm, —at least 35% by weight in magnesia in meal form with grain sizes of, e.g. 100% by weight.
Claims17
1-15. (canceled)
16:
- Dry substance mixture for a refractory batch, usable especially for lining heavy nonferrous metal smelting systems, preferably for lining copper smelting converters, mainly containing
- at least 30% by wt, especially at least 40% by wt of a coarse-grained raw olivine substance, containing forsterite contents of, for example, at least 70% by wt, especially of at least 90% by wt, preferably at least 100% by wt, and having grain sizes corresponding, for example, to 100% by wt, especially 80% by wt, preferably 50% by wt larger than 0.1 mm,
- at least 35% by wt, especially at least 40% by wt magnesia (MgO) in flour form with grain sizes corresponding, for example, to 100% by wt, especially 80% by wt, preferably 50% by wt≦1 mm,
- at least 5% by wt, especially at least 10% by wt silicon carbide (SiC) in flour form with grain sizes corresponding, for example, to 100% by wt, especially 80% by wt, preferably 50% by wt≦1 mm,
- optionally at most 10% by wt, especially at most 5% by wt of a dry finely divided silica (SiO2), preferably in the form of microsilica and/or of a pyrogenic and/or precipitated silica,
- optionally at most 10% by wt, especially at most 5% by wt of at least one further additive for refractory products, such as antioxidants,
- rest up to 100% by wt of respectively at least one of the other solids.
4 more elements
17:
- Dry substance mixture according to claim 16, containing the following solids in the mixing ratio:
- Raw olivine substance:
- 30 to 60, especially 40 to 50% by wt
- MgO:
- 35 to 50, especially 40 to 45% by wt
- SiC:
- 5 to 20, especially 10 to 15% by wt
- SiO2:
- 0 to 10, especially 0 to 5% by wt
- Refractory additives:
- 0 to 10, especially 0 to 5% by wt.
8 more elements
18:
- Dry substance mixture according to claim 16, wherein the raw olivine substance is a natural raw olivine substance and/or a synthetically manufactured forsterite material and the grain size of the raw olivine substance lies in the medium and coarse size range, e.g. between 0.1 and 6, especially between 1 and 6 mm, and preferably has a Gaussian grain-size distribution.
19:
- Dry substance mixture according to claim 16, wherein the MgO content of the magnesia is greater than 90% by wt, especially greater than 95% by wt, and the grain-size distribution of the magnesia flour corresponds to a Gaussian grain-size distribution.
20:
- Dry substance mixture according to claim 16, wherein the silicon carbide flour has a purity of greater than 90% by wt, especially greater than 94% by wt of SiC.
21:
- Refractory batch containing a dry substance mixture according to claim 16, wherein the batch contains, in addition to the dry mixture, at least 2% by wt of a liquid binder in the form of an alkali-low, preferably alkali-free silica sol, calculated relative to the dry solids.
22:
- Batch according to claim 21, wherein the alkali content of the silica sol is less than 1% by wt, especially less than 0.5% by wt.
23:
- Batch according to claim 21, wherein the silica sol is a colloidal dispersion of amorphous silicon dioxide particles in water and has SiO2 concentrations of between 15 and 50, for example, especially between 20 and 40% by wt, wherein preferably the specific surface of the silicon dioxide particles lies between 100 and 400, especially between 200 and 300 m2/g.
24:
- Batch according to claim 21, wherein silica sol is present in proportions between 2 and 10, especially between 3 and 6% by wt, calculated relative to the dry solids.
25:
- Batch according to claim 21, wherein the batch is provided subdivided in a package of at least two containers, wherein the dry solids are packed in one container and the silica sol is packed in the other container.
26:
- Use of a batch according to claim 21, wherein the batch components are mixed to an aqueous compound and then the compound is pressed to molded bricks in a molding press and then the molded bricks are dried, especially to a maximum residual moisture content of 2% by wt.
27:
- Use according to claim 26, wherein the dried molded bricks are fired ceramically in a ceramic furnace, especially at temperatures between 1000 and 1300, especially between 1150 and 1250° C. in oxidizing atmosphere, for example with a firing duration between 4 and 8, especially between 5 and 6 hours.
28:
- Use according to claim 27, wherein the firing conditions are chosen such that the dry and dried components of the batch react with one another not at all or to only a small extent during firing.
29:
- Molded brick manufactured according to claim 26, exhibiting an apparent density in particular between 2.6 and 2.7 kg/m3 and a compressive strength of 25 to 50, especially of 35 to 45 MPa.
30:
- Molded brick manufactured according to claim 27, exhibiting an apparent density of, for example, 2.55 to 2.65 kg/m3 and a compressive strength of, for example, 30 to 55, especially of 40 to 50 Mpa.
31:
- Use of a batch according to claim 21 for the manufacture of a refractory casting compound or of a refractory vibratory compound, wherein the ductility of the compound is appropriately adjusted with additional water, provided the water content of the silica sol is not sufficient for the purpose.