Charge for production of refractory materials

The technical field

The invention relates to refractory materials refractory composition and can be used for manufacturing products for the coating of various thermal plants operating under high temperatures.

The level of technology

It is known that corundum refractories are widely used in metallurgical, chemical, machine building and other industries. Thanks to the set of their unique properties and wide application of further improvement is promising [Cynarski I.S., Degtyareva EV, Orlova G.M. Corundum refractories and ceramics. - M.: metallurgy, 1981. - 168 C.].

Known mixture for the manufacture of refractories containing alumina, aluminium oxide and boric zirconium in the following ratio, wt. %: oxide 68-72, bored zirconium 0,2-0,5, triethanolamine 0,05-0,5, alumina - rest [A.S. 765237, USSR. The mixture for the manufacture of refractories. Semchenko GD and other BI 1980, No. 35]. However, the mixture of this composition is sintered at a high temperature (over 1600°C), which makes the manufacture of refractory products based on it very energy intensive; unfired molded products have low strength; finished refractory products are characterized by high creep; in addition, bored zirconium is an expensive Supplement.

Also known mixture containing additives the Tio ₂introduced during grinding in alumina and allowing to reduce the sintering temperature to 1480-1500° [Bron VA Refractories, 1953, No. 6, s-254], however, this Supplement is recommended for recrystallization of sintering of spherical particles of alumina in the briquette, which is an intermediate in the production of refractory products.

The closest set of features of the present invention, i.e. the prototype, is the mixture for the manufacture of refractories containing oxide, aluminum hydroxide, phosphoric acid and alumacraft ligament (Al(Oh)₃5-10, N₃RHO₄3-5, AHFS 3-15 wt. %, oxide - rest) [A.S. 963976, USSR. The mixture for the manufacture of refractories. Andreev A.V. and other BI 1982, No. 37].

However, the prototype has a high sintering temperature (over 1500° (C)insufficient strength and heat resistance at low temperature sintering, its preparation nizkotexnologichno due to the use of two types of binder.

The invention

Inventive task consisted in developing a charge for making sredneplotnyh corundum refractories in order to reduce the sintering temperature and porosity, as well as to improve the strength and heat resistance.

The problem is solved by creating a batch for the manufacture of refractories, including oxide and phosphate the binder, moreover, it contains aluminium oxide, modified legkorazmyvaemykh aluminate additive composition (for example, aluminum nitrate, formate, aluminum, bauxite, and the like) in an amount of 1-5 wt. %, and as a phosphate binder - lumberport or alumacraft ligament in the following ratio, wt. %:

modified corundum - 90-93;

phosphate binder - 7-10.

Thus, the stated charge for making sredneplotnyh refractories differs from the prototype in that it contains aluminium oxide, modified legkorazmyvaemykh sintering additive aluminate composition in an amount of 1-5 wt. % if their joint mechanical activation. Previously, such additives are not used in the compositions sredneplotnyh corundum refractories for the purpose of lowering the sintering temperature and porosity, as well as improving the heat resistance and strength.

Used in the composition of the oxide corresponds to GOST 30559-98, lumberport ligament (ABFS) (lumberport concentrate) - TU 113-08-606-87; alimohammadian ligament (AHFS) - TU 6-18-166-83, the addition of aluminate composition: bauxite - THE 1711-003-00200-992-95, aluminum nitrate Al(NO₃)₃·N₂O - GOST 3757-75; formate, aluminum Al(NCOA)₃- THE 6-09-01-394-76.

Information confirming the possibility of carrying out the invention

Example 1. 880 g (8%) oxide powder (90% particle size to 0.075 μm, the maximum particle size 0,315 μm) and 50 g (5%) of bauxite as a sintering additive was loaded into a ball mill for mechanical activation within 30 minutes of the Obtained modified oxide are thoroughly mixed with 70 g (7%) alumophosphates ligaments. From the prepared mixture was molded samples using dry pressing (50 MPa), which was annealed at a temperature of 1300°C for 1 h

The resulting samples was determined apparent density, open porosity - according to GOST 2409-95, ultimate compressive strength at room temperature according to GOST 4071.1-94, thermal resistance - according to GOST 7875.2-94.

Example 2. 885 g (88.5 percent) of the oxide powder (90% particle size to 0.075 μm, the maximum particle size 0,315 μm) and 30 g (3%) of aluminum nitrate as a sintering additive was loaded in a planetary mill for mechanical activation within 5 minutes of the Obtained modified oxide are thoroughly mixed with 85 g (8,5%) alumophosphates ligaments. Preparation, heat treatment and testing of samples as in example 1.

Example 3. 890 g (89%) of a powder of oxide (90% particle size to 0.075 μm, the maximum particle size 0,315 μm) and 10 g (1%) of aluminum nitrate as a sintering additive was loaded in a vibrating mill for mechanical activation within 7 minutes of the Obtained modified oxide are thoroughly mixed with 100 g (10%) alumina is orthostatic ligaments. Preparation, heat treatment and testing of samples as in example 1.

Example 4. 885 g (88.5 percent) of the oxide powder (90% particle size to 0.075 μm, the maximum particle size 0,315 μm) and 30 g (3%) of aluminum formate as a sintering additive was loaded in a planetary mill for mechanical activation within 10 minutes Received a modified oxide are thoroughly mixed with 85 g (8,5%) alumophosphates ligaments. Preparation, heat treatment and testing of samples as in example 1.

Examples with other claimed compositions and test results are presented in the table.

As follows from the experimental data presented in the table, the ingredients in the stated proportions (examples 1-4) allows to reduce the sintering temperature, to increase the strength and heat resistance, as well as to reduce the open porosity in comparison with the prototype.

Furthermore, an additional advantage of the claimed technical solution before the prototype is reduced residual resizing when heated (10-13%).

The mixture for the manufacture of refractories, including oxide modified with aluminate additive composition, and a phosphate binder, characterized in that the modification of the oxide is carried nitrate or formate as uminia in number 1÷ 5 wt. %by mechanical activation, and as the binder mixture contains lumberport concentrate in the following ratio, wt. %:

Modified aluminium oxide 90÷93

Phosphate binder 7÷10