COMPOSITION FOR PREPARING A GREEN BODY FOR THE MANUFACTURE OF A REFRACTORY CARBON-BONDED PRODUCT, METHOD FOR PREPARING SUCH A GREEN BODY AND GREEN BODY PREPARED THEREBY

Abstract

The invention relates to a composition for preparing a green body for the manufacture of a refractory carbon-bonded product, a method for preparing such a green body and a green body prepared by such a method.

Claims

1. A composition for preparing a green body for the manufacture of a refractory carbon-bonded product, comprising the following components: at least one refractory raw material, at least one carbon carrier, and at least one binder which comprises: a resin, and at least one initiator which initiates a curing reaction of the resin through ionizing radiation.

2. The composition according to claim 1 having a proportion of refractory base material in the range of 60 to 98% by mass.

3. The composition according to claim 1 in which the percentage of binder is in the range from 0.5 to 10% by mass.

4. The composition according to claim 1 having a binder consisting of an ionically curable resin and a cationic photoinitiator.

5. The composition according to claim 1 having an ionically curable resin in the form of an epoxy resin.

6. The composition according to claim 1 having a cationic photoinitiator in the form of an onium salt.

7. The composition according to claim 1 with a binder consisting of a radically curable resin and a free radical photoinitiator.

8. The composition according to claim 1 with a radically curable resin in the form of acrylate resin.

9. The composition according to claim 1 having a free radical photoinitiator selected from the group: benzophenone, aromatic phosphine oxides, phosphonates, peroxides or azo-compounds.

10. A method for preparing a green body for the manufacture of a refractory carbon-bonded product, comprising the following steps: providing a composition, the composition comprising the following components: at least one refractory raw material, at least one carbon carrier, and at least one binder which comprises a resin, and at least one initiator which initiates a curing reaction of the resin through ionizing radiation, exposing the composition to such an ionizing radiation that the initiator initiates a curing reaction of the resin.

11. The method according to claim 10, wherein the composition is exposed to X-rays or gamma radiation.

12. The method according to claim 11, wherein the composition is exposed to a radiation dose in the range from 1 to 100 kGy.

13. A green body for preparing a refractory carbon-bonded product which is produced by a method, the method comprising: providing a composition, the composition comprising the following components: at least one refractory raw material, at least one carbon carrier, and at least one binder which comprises a resin, and at least one initiator which initiates a curing reaction of the resin through ionizing radiation, exposing the composition to such an ionizing radiation that the initiator initiates a curing reaction of the resin.

Description

EXAMPLE 1

[0072] The composition according to the invention according to embodiment 1 contains the components in the mass percentages shown in table 1 below.

TABLE-US-00001 TABLE 1 Component Proportion [wt %] Fused magnesia 88.5 Graphite 8.5 Binder 3.0

[0073] According to embodiment 1, a refractory raw material was provided in the form of fused magnesia. The grain size of the fused magnesia was in a range between larger 0 and 5 mm. The fused magnesia contained a proportion of 98 wt % MgO and 2% by-phases, particularly in the form of CaO, SiO.sub.2, Al.sub.2O.sub.3 and Fe.sub.2O.sub.3.

[0074] The carbon carrier of the composition according to embodiment 1 was present in the form of graphite with a proportion of carbon of 94 wt %.

[0075] The binder included a proportion of resin in the form of epoxy-novolak of 85 wt % and a proportion of an initiator in the form of triaryl sulfonium-hexafluoroantimony salt of 15 wt %, relative in each case to the total weight of the binder.

[0076] The corrspondingly prepared composition was mixed at a temperature of 50 C. for 10 minutes. Then the mixed composition was allowed to rest.

[0077] The composition was then moulded by pressing to form a moulded body, and this moulded body was then exposed to x-ray radiation with a radiation dose of 3.6 kGy. The x-ray radiation caused the triarylsulfonium-hexafluoroantimony salt to release protons, which initiated a chain reaction of the epoxy-novolak, wherein the epoxy groups of the epoxy-novolak polymerised with each other until the epoxy-novolak was completely cured.

[0078] Then, a green body was obtained with which a refractory carbon-bonded product could be prepared.

[0079] This green body was subjected to a temperature of 90 C. as part of a postreatment step, thereby improving the strength properties of the green body.

EXAMPLE 2

[0080] The composition corresponds to that of embodiment 1, the only difference being that the binder contained a proportion of resin in the form of acrylate resin, specifically pentaerythritol triacrylate (CAS number 3524-68-3) of 85 wt % and a proportion of an initiator in the form of ethyl-(2,4,6-trimethylbenzoyl)phenylphosphinate of 15 wt %, relative in each case to the total weight of the binder.

[0081] The correspondingly prepared composition was mixed at a temperature of 50 C. for 10 minutes. Then the mixed composition was allowed to rest.

[0082] The composition was then moulded by pressing to form a moulded body, and this moulded body was then exposed to x-ray radiation with a radiation dose of 3.6 kGy. The x-ray radiation caused the ethyl-(2,4,6-trimethylbenzoyl)phenylphosphinate to generate radicals, which initiated a chain reaction in the acrylate resin, so that it polymerised and completely cured.

[0083] This yielded a green body for preparing a refractory carbon-bonded product.

[0084] This green body was exposed to a temperature of 90 C. in a post-treatment step, thereby improving the strength properties of the green body.