SU1328333A1 - Refractory mixture for manufacturing roastless articles - Google Patents

Abstract

The invention relates to the field of ferrous metallurgy, namely, a refractory composition, for the manufacture of unburned products for steel casting. The aim of the invention is to increase the metal resistance, heat resistance and mechanical strength of refractory products used in steel casting. The refractory mass for the manufacture of unburned products includes, in wt%: a complex binder based on acidic wastes 4-8; graphite 9-14; aluminum metal 2-4} jointly ground mullite-corundum chamotte, clay and zircon sand fractions of 0.088 mm in the ratio

Description

The invention relates to ferrous metallurgy, namely, refractory products and for steel casting.

The aim of the invention is. increase of metal resistance, heat resistance and mechanical strength of products.

The complex binder is a binder based on acidic wastes and a sulphite-glycine slip. Acid wastes are used after electropolishing of stainless steel pipes and contain wt.%: H5PO 4 51.9; HjSO 21.6; Fe (II) + Fe (III) ions 1.52; CrO5 ions, 55; Ni (II) ions 1.05, the rest -.

The introduction of joint sand in joint grinding will make it possible to grind it to a fraction of 0.088 mm and evenly distribute it in the mixture, which will improve the heat resistance of finished products, the chemical inertness to the molten metal and reduce thermal conductivity.

The use of joint grinding of mullite-corundum fireclay, clay and zircon sand makes it possible to obtain an intermittent grain composition of the mass, which contributes to the compact packing of grains and obtaining high-density products with high strength properties and metal resistance.

The introduced metallic aluminum has a positive effect as an anti-oxidant additive to graphite and for the formation of A1H2P04, which has strong adhesive properties.

The introduction of co-milling of less than 35% by weight does not provide the necessary packing density for the grains, and a small amount of the clay component is introduced, which plays the role of a binder. The addition of more than 40 wt.% To the mass slightly increases the strength properties, since, besides joint grinding in the form of a finely ground fraction, graphite is also added, and the presence of a twisted amount in the fine-grained mass of ush leads to repressive cracks.

Introduction to this composition of graphite less than 9 wt.% Will not reduce the wettability of these products with metal, which leads to a decrease in metal resistance. In addition, low content. graphite- can lead to the overgrowth of the canal of the glass and collector by various spinel formations. The introduction of more than 14 wt.% Into the mass of graphite leads to a decrease in mechanical strength and more intensive oxidation of graphite, which adversely affects the structure of products. The latter leads to an increase in the rate of flow of diffusion processes of chemical

interaction at the metal-refractory boundary, which leads to corrosive and erosive destruction of products during steel casting. In order to reduce

The oxidizability of graphite is doped with metallic aluminum, which changes the character of the interaction of the components of the mass with the oxygen in its composition.

As the temperature on the surface of the product explodes, metallic aluminum exhibits an increased activity towards oxygen, as a result of which AljO is formed.

This process occurs with an increase in volume of 40%, increasing the density of the surface layer of the refractory, as the heating of the product begins with the surface layers. Increase

the density of the surface layer It leads to a decrease in the oxidability of graphite and, consequently, to the increase in metal; lostability

Especially intensively proceeds

This process in the proposed composition of materials. So aluminum, in contact with the complex binder, which contains a solution, reacts with the latter. With

In this case, the oxidized layer of each aluminum particle is purified: its activity significantly increases with respect to oxygen.

In addition, metallic aluminum has another positive effect, namely, immediately after pressing in the raw, its reaction begins to take place with and, which are part of a complex binder, with the formation of monosubstituted aluminum phosphates and aluminum sulfates: A1 + 3H, PO , -Al (HjP04), + 1.5 Hj, 2A1 + (SO), + 3H, j.

 Formed compounds have high adhesion properties.

and enhance the degree of interaction

component bindings with components

masses.

Thus, the protective effects of metallic aluminum against the oxidation of graphite are manifested in the intensification of the processes of interaction with the complex binder and the processes of compaction of the structure of that part of the fire that is exposed to high temperatures.

The introduction of metallic aluminum into the proposed mass of 2–4 wt.% Depends on its dispersity. Less than 2 wt.% A1 is not enough to ensure the doping ability, and more than 4 wt.% Leads to a significant expansion accompanying the violation of the monolithic structure of the products,.

The introduction of a complex binder consisting of acid waste and a sulphite clay slurry ensures high mechanical strength of the products. After heat treatment. This binder has high adhesive properties and has a low cost.

Introduction of less than 4 wt.% Of the complex binder into the composition does not provide the necessary plasticity of the mass and, therefore, workability, resulting in a decrease in strength properties, and more than 8 wt.% Binder leads to a glass phase content and a decrease in heat resistance. .

The excess of the lower and upper limits of mullite-corundum chamotte leads to a decrease in the physical-ceramic properties of the products.

The introduction of mullite-corundum chamotte into the expected mass is determined primarily by the fact that it is the main filler with a grain composition of 3.0-0.5 mm. Such a grain composition is necessary for the formation of the main frame of products.

Unburned glasses and collectors made of the expected mass have physico-ceramic properties due to the introduction of joint grinding of the listed components in the specified ratio, as well as metallic aluminum and graphite on a complex bond.

The complex of the properties obtained is not adequate to the properties introduced by each component separately, and as a result of the joint use of air

five

0

0

five

0 5

t 0

five

No new effect due to the phenomenon of synergism.

Under identical conditions, a comparative analysis of the properties of products of the proposed mass and known is carried out.

In order to determine the physico-ceramic properties of unburned glasses and collectors, samples of the refractory mass of the proposed composition are prepared as follows. Mullito-corundum chamotte fractions 3-0.5 mm and 1/4 part of the complex binder solution are loaded into the runner after 3 minutes. mixing, half of the joint grinding of mullite-corundum chamotte, clay, zircon, graphite, aluminum metal, 1/4 of the binder is introduced and mixed for another 3 minutes. Then, the remaining joint grinding and the rest of the complex binder are loaded, the mass is stirred for another 4 min.

From the prepared mass, samples are pressed at a specific pressing pressure of 50 fla in size d 36 and h 50 mm and specimens of special dimensions. for determining metal resistance, heat resistance, compressive strength.

Drying of the samples is carried out at 100 ° C and then heat treated at 500 ° C in a furnace for 4 hours. In identical conditions, samples of a known mass are also prepared and the properties of the samples of the known and proposed mass compositions are examined.

The compositions of the studied masses in determining the optimal amount of joint grinding are given in table 1; physico-chemical properties of the masses (table 1) - in table 2; The composition of the studied masses in determining the optimal ratio of components in the joint grinding is given in Table 3; physico-ceramic properties of the masses (Table 3) in Table 4.

Claims (2)

1. A refractory mass for the manufacture of unburned products, including a phosphate binder, an alumina-containing component, graphite, and an additive, characterized in that, in order to improve metal resistance, heat resistance, and mechanical strength, it contains 51 phosphate binder complex binding based on acid wastes, as a glyiozem-containing component - mullite-corundum chamotropic of 3.0-0.5 mm, as an additive - metallic aluminum and additionally jointly ground mullite-corundum chamotte, fractions 88 mm, clay and zircon sand fractions of 0.088 mm in the ratio (1, 4-1, 6): 1, 0: (1.4-1.6) in the following ratio of components, wt.%: Complex linking to acid base waste4-8. 42.5 40 37.5 35 32.5 6.5 9.0 11.5 1.0 2.0 3.0 2.0 4.0 6.0 14.0 16.5 4.0 5.0 8.0 10.0 Graphite Aluminum metal Co-milled mullite-corundum chamotte fractions of 0.088 mm, clay and zircon sand fractions of 0.088 mm in the ratio (1.4-, 6): 1.0: (1.4-1.6) Mulito-corundum chamotte fractions 3.0-0.5 mm 2. Mass according to claim 1, characterized in that the mullite-corundum chamotte fractions of 0.088 and 3.0-0.5 mm are taken in a ratio of 1: (2,). Table 1 11.5 3.0 6.0 14.0 16.5 4.0 5.0 8.0 10.0 P 0 2 5.0 5.2 4.1 4.2 3.5 3.4 3.8 3.6 4.8 4.9 5.0 5.3 4.4 4.6 3.6 3.8 3.5 3.9 4, 9 5.3 5.2 5.6 4.5 4.6 4.6 1328333 10 Table 4 24.5 25.5 26.8 28.1. 32.1 33.7 33.1 32.8 30.0 29, t 23.1 24.2 30.8 32.1 35.8 38.3 34.1 33.9 28.9 29.4 22.9 23.7 28.7 29.2 31.2 15.8 15.4 14.4 14.5 14.1 14.3 14.2 14.2 14.9 14.8 15.2 15.0 14.1 14.2 13.9 14.2 14.0 14 , 4 15.3 15.3 15 15.0 14.1 14.4 14, 3 4.4 2 4.6 A, 9 5, 18 17 18 5 16 Editor N. Gunko Compiled by O, Motorika Tehred M. Khodanych Order 3449/27 Circulation 587 Subscription VNIIPI USSR State Committee for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5 Production and printing company, Uzhgorod, Projecto st., 4 14.2 4.2 14.4 15.0 15.1 Proofreader G. Reshetnik