UA57873C2 - composition of material for a self-burning electrode - Google Patents

Abstract

Material for a self-burning electrode contains thermoanthracite of different granulometric composition, additives, and coal-tar pitch binder. As the additives, substandard residuals of alloy produced at the plant and coke with the density that differs by ± 4% from the density of the coal-tar pitch binder are used. The contents of the components of the material, in percent by mass, are as follows: Thermoanthracite, particles of up to 3 mm 20 … 24 % Thermoanthracite, particles of 3 … 15 mm 12 …16 % Thermoanthracite, particles of 15 … 20 mm 8 … 12 % Coke with the density of 1.2 … 1.3 t/m3, particles of up to 1 mm 30 … 34 % Substandard residuals of the alloy, particles up to 1 mm 1 … 5 % Coal-tar pitch binder 25 … 29 %

Description

Description of the invention

The proposed invention relates to the field of ferrous and non-ferrous metallurgy and, in part, to 2 electric arc furnaces equipped with self-heating electrodes.

The known composition of the electrode mass of the self-heating electrode (a.s. USSR Mo851794, Cl. NOB5 B 7/09, B.1. 1981, Mo28), includes a weight of 90: bitumen 8...8; brown coal 12...14; lime 14...17; iron oxide in the form of scale, the rest.

The disadvantage of this composition should be attributed to the low electrical conductivity of the heated electrode mass, which increases its consumption by 75% compared to the consumption of traditional self-heating electrodes. This leads to an increase in the price of products and an increase in labor costs for smelting the alloy.

The closest solution to the proposed composition is the electrode mass (Kayunz Isiku Takso.

Artificial graphite electrode, 1970, Mobo0O, p. 30 - 38), which consists of: metallized additive - Ge2zhO3 -1...2; coal pitch 15...28; thermal anthracite the rest.

The disadvantages of this mass include the absence of coke, which helps to strengthen the electrode, and the presence of iron oxides, which above a temperature of 5707C begin to recover according to the reaction: 2гБе2О3 о- 2БезОо, нд СОТ i) with the formation of volatile compounds that dissolve the liquid electrode mass, increasing porosity and reducing the mechanical strength of the electrode.

The task of this technical solution is to reduce electrical costs in self-heating electrodes by increasing their density and electrical conductivity of the electrodes, as well as disposal of substandard products.

This problem is solved by the fact that in the composition of the electrode mass of the self-heating electrode, which contains heat anthracite of various granulometric sizes, additives, the binder is coal pitch, it uses as additives (ee) substandard metal residues of alloys melted in furnaces with electrodes with this mass composition, as well as coke density with a difference of 495 from the density of coal pitch, while the ratio of he components in the mass in weight 9o is as follows: IS o) thermal anthracite fraction up to Zmm 20...24; thermal anthracite fraction 3...15mm 12...16; thermal anthracite fraction 15...20 mm 8...12; "coke with a density of 1.2 - 1.3 t/m3 fractions up to 30...34 mm; - with non-conditional alloy additives fraction up to mm -1...5; t connector - coal peck 25...29, and?

Moreover, non-standard ferrosilicon crushed to a fraction of up to mm is used as metal additives.

The ratio of the fraction of thermal anthracite is explained by the fact that when the fraction to Zmm is less than 2096, the cavity between the large pieces is not densely filled, the mass after heating has low strength and high specific electrical resistance (PEO).

When in the composition of the mass, the amount of the thermal anthracite fraction up to Zmm is more than 2495, the costs (oo) of the binder increase, the density of the fired mass decreases, and the PEO increases.

When fractions of thermal anthracite 3...15 mm in the composition of the mass are less than 1295, the cavity between the pieces of 15...20 mm is not filled tightly, the mass after heating has low strength and high PEO. c» When the amount of thermal anthracite fraction 3...15 mm in the composition of the mass exceeds 1695, the cavity between the pieces of 15...20 mm increases, the strength of the mass decreases after heating.

When the composition of the mass of pieces of 15...20 mm is less than 8,957, the consumption of the binder increases, the density of the fired mass decreases, and the PEO increases.

When the composition of the mass of pieces of 15...20 mm is more than 12905, the cavities between the pieces of the mass increase and the mass after heating has low strength and high PEO. Coke in the composition of the electrode mass should have a density with a difference of 495 from the density of coal pitch in the liquid state, which is 1.25...1 27 tim3. 60 When the density of coke is less than 495 of the density of pitch, the coke in the liquid mass moves uphill, and when its density is greater than 495 of the density of pitch, the coke moves downward. Both the first and the second unbalance the composition of the mass in the coking zone, which reduces its strength and electrical conductivity.

To reduce the PEO, an additive of non-standard alloy of this production up to 1 mm in size is added to it in the amount of 1...590. bB The size of the additive is determined by the fact that it must be evenly distributed in each microvolume of the mass.

When the additive is introduced, it is less than 195 PEO and more than 90 Ohm.m.10 5, which does not correspond to TU-48-12-8-84, and when -D-

additives greater than 595 have a tensile strength lower than 1.47 Pa, which also does not satisfy TU-48-12-8-84.

As for the binder - coal pitch, its amount by mass in the range 25...2996 is due, on the one hand, to the fact that with a large percentage of pitch (more than 29905), the fired mass has low strength, and on the other hand, it must completely fill the entire volume of the electrode casing, that is, it must be sufficiently liquid.

When the composition of the mass with pitch is less than 2595, the mass does not completely fill the electrode casing, which leads to the appearance of cavities and burning of the casing, and more than 2995 pitch leads to an increase in the porosity and PEO of the electrode.

An example of the use of the electrode mass according to the composition of the invention for use in self-heating electrodes of ore reduction furnaces for smelting ferrosilicon. 70 Thermoanthracite electrode GOST 4794-75 heated at a temperature of 135076 was used in all compositions.

Cooled thermal anthracite was crushed on a dense crusher and dispersed into fractions up to Zmm, 3...15mm, 15...20mm.

Coke, which contains iron 2.395, with a density of 1.3t/m, was crushed to a fraction of up to imm. As a metal additive /5 ferrosilicon grade Ф-65 fraction up to mm was used.

The percentage of pitch in the composition was chosen to be 25905, because it already ensured complete filling of the electrode casing with mass.

A total of 13 variants of mass compositions were tested in the example, including the prototype.

Each mass composition was melted at a temperature of 130...1407C. This mass was filled into molds in the form of cylinders of diameter 250 mm, which were heated to a temperature of 9007C at a rate of 1007C per hour, kept at this temperature for 3 hours, and then cooled in coke backfill to room temperature.

Samples of 260 x 50 mm made from this fired mass were tested for PEO according to TU-48-12-8-88 and mechanical shear strength according to the same TU.

Samples of the fired mass according to the composition of the prototype gave the following result: Ha mechanical strength - 1.49 MPa, PEO - 102.0 Ohm.m.1075, (5)

The experimental data are summarized in a table.

As can be seen from the table, all examples of mass compositions, which are reflected in the formula of the invention, have better indicators than

TU-48-12-8-88 and in the prototype.

Thus, the invention solves the task - indicators of the burned mass according to the invention formula above "OO prototype and according to TU-48-12-8-88, which ensures a reduction of electrical costs in the electrodes, and also contributes to the disposal of substandard products of this production. Ges t (0 Thermoanthracite (Coke fractions up to imm Ferrosilicon, fractions up to 1mm "7 o decims dimensions somm vv v lyu « 2" | in 81ю0111 120 2 rya 91811111 in 2 s. krav 81011116 18 g" NS PEN NI NE TI PO NNYA POLO TONYA OO POS 5 ryu 91 10yu61111111111251 25 s ayu | 21 810yu01105 618 - fri 1918010000900011010111116yu1155 oyu i vm111111111111tv11mo sa

From Pnvvntnianit same veil " - composition of ferrosilicon grade FS - 65: 5i -66.0; Mp -04; g -04; P -0.05; 5-0.035A1-2.0; C - 0.1; the rest Be .

Claims (2)

The formula of the invention Ф) 1. The composition of the electrode mass of a self-heating electrode, which contains thermal anthracite of different km granulometric size, additives, a binder - coal pitch, which is distinguished by the fact that as additives it uses substandard residues from the production of alloys melted in furnaces with electrodes with this mass , as well as coke density with a difference of 495 from the density of coal pitch, while the ratio of components by weight in weight 9o is as follows: thermal anthracite fraction up to 3 mm 20-24 thermal anthracite fraction 3-15 mm 12-16 65 thermal anthracite fraction 15- 20 mm 8-12 coke with a density of 1.2-1.3 t/m? fractions up to mm 30-34 non-standard alloy additives fractions up to mm 1-5 binder - coal pitch 25-29. 2. The composition of the electrode mass according to claim 1, which differs in that substandard ferrosilicon crushed to a fraction of up to 1 mm is used as an additive to the electrode mass of ferrosilicon melting furnaces. Official bulletin "Industrial Property". Book 1 "Inventions, useful models, topographies of integrated microcircuits", 2003, M 7, 15.07.2003. State Department of Intellectual Property of the Ministry of Education and Science of Ukraine. c schi 6) (ze) ich- (ee) cha IS c) - with . and? 1 -I (ee) - 50 syu» ime) 60 b5