Batch for producing an unshaped refractory ceramic product, method for producing an unshaped refractory ceramic product, and an unshaped refractory ceramic product produced thereby

Abstract

The invention relates to a batch for producing an unshaped refractory ceramic product, to a method for producing an unshaped refractory ceramic product, and to an unshaped refractory ceramic product produced by the method.

Claims

1. A batch for producing an unshaped refractory ceramic product which has the following features: 1.1 the batch comprises the following components: 1.1.1 at least 60 mass % of a main component in the form of at least one raw material based on magnesia; 1.1.2 a component in the form of at least one chemically modified starch ether; and 1.1.3 a component in the form of at least one water-soluble chemical binder; 1.2 the batch comprises the following substances in the following mass proportions: 1.2.1 less than 10 mass % calcium oxide; and 1.2.2 less than 10 mass % carbon.

2. The batch according to claim 1 with a main component in the form of at least one of the following raw materials: sintered magnesia or fused magnesia.

3. The batch according to claim 1, with a proportion of the main component in the range of from 60 to 98 mass %.

4. The batch according to claim 1, with the component in the form of the at least one chemically modified starch ether in the form of at least one of the following chemically modified starch ethers: hydroxyalkyl starch ether, carboxyalkyl starch ether, hydroxyalkyl-carboxyalkyl starch ether, carbamoyl starch ether or cyanoalkyl starch ether.

5. The batch according to claim 1, with a proportion of the component in the form of the at least one chemically modified starch ether in the range of from 0.01 to 1.0 mass %.

6. The batch according to claim 1, with the component in the form of the at least one water-soluble chemical binder in the form of at least one of the following binders: at least one water-soluble sulphate, at least one water-soluble phosphate, or at least one water-soluble silicate.

7. The batch according to claim 1, with a proportion of 1 to less than 40 mass % of at least one of the following raw materials for setting the basicity of the batch: limestone, dolomite, doloma, magnesite or olivine.

8. The batch according to claim 1, with a component in the form of at least one clay.

9. The batch according to claim 1, with a component in the form of fibres.

10. A method for producing an unshaped refractory ceramic product comprising the following steps: 10.1 providing a batch, the batch comprises: at least 60 mass % of a main component in the form of at least one raw material based on magnesia; a component in the form of at least one chemically modified starch ether; and a component in the form of at least one water-soluble chemical binder, wherein the batch comprises the following substances in the following mass proportions: less than 10 mass % calcium oxide; and less than 10 mass % carbon; 10.2 mixing the batch with water; 10.3 applying the batch mixed with water to a surface; and 10.4 firing the batch applied to the surface to form an unshaped refractory ceramic product.

11. An unshaped refractory ceramic product produced by a method, the method comprising: 11.1 providing a batch, the batch comprises: at least 60 mass % of a main component in the form of at least one raw material based on magnesia; a component in the form of at least one chemically modified starch ether; and a component in the form of at least one water-soluble chemical binder, wherein the batch comprises the following substances in the following mass proportions: less than 10 mass % calcium oxide; and less than 10 mass % carbon; 11.2 mixing the batch with water; 11.3 applying the batch mixed with water to a surface; and 11.4 firing the batch applied to the surface to form an unshaped refractory ceramic product.

Description

(1) An exemplary embodiment of the invention will be described in greater detail hereinafter.

(2) The exemplary embodiment relates to a batch for producing an unshaped refractory ceramic product in the form of a gunning mass.

(3) The batch has the following components in the following mass proportions, in each case relative to the total mass of the batch:

(4) a main component in the form of sintered magnesia: 92.65 mass %;

(5) a component in the form of at least one chemically modified starch ether in the form of the following chemically modified starch ether: hydroxyalkyl-carboxyalkyl starch ether: 0.15 mass %;

(6) a component in the form of at least one water-soluble chemical binder in the form of the two following water-soluble chemical binders:

(7) water glass: 3.5 mass %; and

(8) aluminium sulphate: 1.0 mass %;

(9) a component in the form of clay in the form of aluminosilicate clay: 2.5 mass %;

(10) a component in the form of fibres in the form of cellulose fibres: 0.2 mass %.

(11) Calcium oxide and carbon were provided in this batch in the following mass proportions:

(12) calcium oxide: 3.1 mass %;

(13) carbon: less than 0.1 mass %.

(14) The following oxides were also provided in the batch, in each case in the following mass proportions:

(15) MgO: 89.4 mass %;

(16) SiO.sub.2: 5.5 mass %;

(17) Fe.sub.2O.sub.3: 0.5 mass %;

(18) Al.sub.2O.sub.3: 0.8 mass %;

(19) Cr.sub.2O.sub.3: less than 0.1 mass %;

(20) Na.sub.2O: 0.7 mass %.

(21) A gunning mass was then produced from the accordingly provided batch, and this gunning mass was sprayed onto the refractory lining of an electric arc furnace (EAF) for repair thereof.

(22) To this end the batch was firstly introduced in the form of a dry mixture into a spraying machine and was conveyed through a tube to a spraying lance by means of compressed air. The water was injected into the batch in the spraying lance in a proportion of 15 mass % relative to the batch without water. As a result of the corresponding injection of water into the batch, a gunning mass was obtained. The gunning mass obtained accordingly was sprayed by means of the spraying lance onto the refractory lining of the EAF to be repaired. Here, the gunning mass had only a very low rebound of approximately 15%. A curing reaction of the water-soluble chemical binder of the batch was initiated on account of the water, so that the gunning mass sprayed onto the refractory lining cured. The EAF was then heated, whereby the cured gunning mass was acted on with a temperature of approximately 1660° C. and the sintered magnesia thus sintered in such a way that a sintered basic refractory ceramic product was obtained from the gunning mass.