SU644747A1 - Ceramic mass - Google Patents

Description

contains these components in the following ratio, wt. % s

66-68 19-21 12-14

The ceramic mass makes it possible to manufacture refractory products, the crystalline structure of which consists mainly of two monomineralic phases: mullite and tialite () in an equimolar ratio of 1: 1.

The following raw materials can be used to prepare a ceramic mass and to obtain a ceramic of a given mineral composition: synthetic - mullite and thialite; reactive - amorphous silica and titanium dioxide, technical alumina; natural - refractory clay and kaolin of wet enrichment, as well as kyten-sillimanite concentrate.

Depending on the method of preparing the raw materials, ceramic products can be made both fine and coarse-grained. The molding of products without clay delivery is carried out, depending on the serum composition of the filler, by semi-dry pressing, tamping or slip casting, and the masses, including clay or kaolin, can also be processed by plastic method.

To obtain refractory products of high heat resistance, mixtures containing oxides of aluminum, silicon and titanium in the following amounts, weight, are prepared. %:

66.00

Oxide

aluminum 20.00

Silica 14.00

Titanium oxide 67.00

Oxide

Aluminum II 21.00

Silica 12.00

Titanium oxide 68.00

Oxide

I aluminum 19.00

Silica 13.00

Titanium oxide

In the semi-dry molding compounds, as an addition, (more than 100%), 6 wt. % 5% aqueous solution of polyvinyl alcohol; in slip mass - 30 wt. % water and 0.3 weight. % carboxylmethylcellulose; moisture content of plastics 21-24%.

Mullite and thialite are synthesized by solid-phase sintering for 12 h at 1750 ° С from a mixture of alumina with silicon oxide and titanium oxide; chamotting of the mass was carried out for 6 h at 1650 ° €.

Samples are formed from semi-dry and plastic masses - plates with dimensions 210X70X XIO mm. Pressing (double-sided, two-stage) is carried out at a specific load on stage I at 500 kgf / cm and 1000 kgf / cm at stage II (holding under load for 7 s).

From slip masses make samples in the form of hollow cylinders with a height of 150 ML1, a diameter (outer) of 50 mm and a wall thickness of 10 mm.

After drying (24 hours in air and then in a drying cabinet at 105 ° C), the samples are sintered in electric furnaces with silyt heaters for 12 hours at 1500 ° C.

The refractoriness of the ceramic products of mullite-thialitic composition lies within 1760-1 to 20 ° С. The microstructure of the samples with relatively long heating (144 h) in a weakly oxidizing medium at 1450 ° С does not undergo noticeable changes.

Shrinkage of products from non-chambered masses after calcination at 1500 ° C ranges from 2-4% for products from reactive raw materials and for products from masses including natural materials, shrinkage of products based on a pre-sintered filler is 2-3 times less. Thermomechanical, thermophysical and thermal properties of samples of mullite-thialitic ceramics are presented in the table.

As can be seen from the table, the ceramic mass of the proposed composition allows to obtain refractory products that are characterized by good refractoriness and heat resistance. The latter circumstance in combination with a sufficiently large mechanical strength is especially important from the standpoint of manufacturing refractory products operating under stringent conditions.

Claims (2)

1.Patent UK No. 1424239, cl. From 04 to 35/10, published. 1976. 2. The patent of Great Britain No. 1119132, cl. From 04 to 35/10, published. 1968.