SU998336A1 - Carbonaceous composition for self-roasting electrodes - Google Patents

Description

one

The invention relates to the electrode industry, in particular, to the preparation of carbon-containing masses for self-baking electrodes of mine-repair electric furnaces.

Known carbon-containing mass of including, wt.%:

Coal

peck15-25

Prografted core

coke containing 1, 5-8 wt. silicon carbide thermoanthracite. Rest

However, self-burning electrodes obtained on its basis have insufficient operational durability.

The closest to the technical essence and the achieved effect to the proposed is a mass of 2J, soda neigh, max.

Coal tar 18-28

Cox10-AO

Silicon carbide 25-50 Thermoanthracite Else The disadvantage of the known mass is that the electrodes obtained on its basis have a relatively low electrical conductivity.

The aim of the invention is to increase the electroconductivity of the electrodes. The goal is achieved by the quality of a carbide-silicon-containing component, the mass contains pro, 5 graphitized carbon-oxide carbide material in the following ratio, wt.%: Coal coal 20-28

20 Coke15-0

Prografted carbon-carbon carbide material Thermoanthracite Else The carbon-dioxide-carbide material contains, masd: silicon carbide 15 alumina 1-15 iron oxide (2) 1-10; magnesium oxide 1-5; calcium oxide -5} carbon else. The prografted carbon-oxide carbide material is. is a complex composite material, which is specially prepared for a given mass from the waste of electrode plants by blending and thoroughly mixing intergrowths of the corner heat insulating protective backfill of calcination and graphitization of electrodes, shavings of roughing graphite electrodes, etc., products, dust and sludge from gas cleaning of production shops in a ratio that provides for obtaining a material of the specified composition, the same material can be obtained by composing a mixture containing oxides (SiO, AI, 0 ., - j ,, FeO) and natural graphite subjected to high-temperature treatment (above 1800 s). In this material, graphite carbon is distributed in elementary volumes evenly and surrounds with a film. Each oxide, carbide, and oxycarbide particle. This provides a sufficiently high electrical conductivity of the material and a high density of contact of its components, which, together with low reactivity, leads to an improvement in the quality of the carbon-containing mass and the operational durability of self-burning electrodes. The content of prografted carbon-doxocarbide material in the proposed composition of the mass should be within the masses. Decrease, its amount less than 15% does not significantly affect the properties of the electrode. Increasing the proportion of prografted carbon-oxide-carbon material more AO does not lead to further changes in the properties of the electrode masses. One of the factors ensuring the operational durability of self-baking electrodes is the optimal binder content in the carbon-containing mass. Practice established that the content of the pitch. must be 20–28 wt. Mass with a content of coal ekd requires a considerable 64 energy expenditures for coking the electrode, does not ensure the optimum level and position of the coking zone. Reducing the amount of pitch to less than 20% does not provide a solid connection between the components, the peako reduces the physicomechanical properties of the self-burning electrode. The optimum coke content in the proposed composition of the carbon-containing mass is wt.%. A decrease in its amount of less than 15% will cause a decrease in the mechanical properties of the electrode. With an increase of more than Q%, the thermal resistance of the electrode will decrease. EXAMPLE Thermal anthracite (GOST) containing up to 5% ash j up to 0.3% moisture, up to 1.9 sulfur and with a yield up to 0.5% volatile, specific electrical resistivity up to 2000 Ohmmm / is used for preparing the masses. m DENSITY 1.8-1.9 g / cm and the following fractional composition, wt.%: Minus 4 mm 30-40 k-IQ mm 25-30 10-20 mm. 30-35 Plus 20 mm 5. Coal coke (GOST 18686-73), containing up to 10.5% ash, up to 2% sulfur, up to 5% moisture and with a yield up to 1.2% volatile, electrical resistivity up to 900 Ohmm / m and containing a fraction of minus 0, 07 mm at least 20% and minus 1 mm - the rest. Coal-tar pitch with softening temperature b570 C (GOST 10200-73), ash content not more than 0.3%, moisture content not more than 0.5%, and volatile 53-63% is also used. The prografted carbon-oxide-carbide material has the same fractional composition as the thermoanthracite. The solid components are calcined at IZOO-UOO C, then crushed, followed by sieving on drum screens or screens. The prepared materials are metered by the types of raw materials and granulometric composition in accordance with this recipe-mass, and then, together with the binder, are fed to the mixer, where they are mixed for 3-5 minutes at an temperature of 130-18 ° C, after which the asy is poured into molds with rickets loaded into self-burning electrodes. The composition of the masses is given in table. one.

For compounds 2 and 3, the prografted carbon-oxide-carbide material has the ratio of ingredients corresponding to their average value (SiC 28 masD, 8 masL, FeO 5 May L, SiOji 5 masD, MgO 3 masD, CaO 3 May L, C - the rest for the compositions and 5 - the smallest for oxides and carbide, and 6 and 7 - the greatest for them.

Each composition is separately prepared in an SOO-liter steam-heated mixer at TZZ-T O C and a mixing time of 50 minutes. The finished carbon-containing mass is molded in dry metal forms into briquettes weighing 2-3 kg. The manufactured mass is placed in a metal casing with a diameter of 60 mm and a height of 300 mm and heated in a furnace without air access to a speed of 100 degrees / hour

aged at a final temperature of 3 hours. The obtained calcined samples of the experimental masses are subjected to technological testing according to TU W-IZ8-79. The test results are presented in Table. 2

From Table 2, it is evident that the use of the invention makes it possible to increase the conductivity of the electrodes by 15-25%.

The use of the proposed composition of the mass will reduce the cost of 1 ton of mass by 3-15 RUB. due to the use of prografted carbonoxide carbide material to replace deficient coke.

In comparative tests of the proposed mass, a reduction in the consumption of electrodes was obtained by 6–8 compared with

with the famous.

Table 1

Thermoanthracite Coke

Silicon carbide

Prografted carbon-oxide carbide material

Coal

pitch

The composition of carbon-containing masses

indicators

Tensile strength, kgf / cm

Electrical resistivity, Ohm.-mm / m

50 25 25 37.5 25 26

40

15 27.5 15 17

25

15 27.5 "O 17.5 15 25

20 2

20 20 28 28

Table 2.

wt.%

19.1 21.8 22.2 20.2 19, t 20.7 8k, B 79.6 76.9 82.2 83.7 80.1

79983368

Claims (2)

1. Carboniferous mass for 2. The mass according to claim 1, of tl and h of humming electrodes, including the fact that the prografted organic thermoanthracite, coke, stone-5 carbon-oxide-carcass material and polyurea-containing peg and mash: silicon carbide component ex. sweeping - alumina 1-15; iron oxide in order to increase - (2+) 1-10; silicon oxide 1-10; oxide of electrical conductivity, as carbide-magnesium 1-5; calcium oxide 1-5; carbon-containing component, it is about the rest, contains prografted carbon-oxide-carbide material in the following - Sources of information, the ratio of components, mas.y: taken into account during the examination of the coal 1. USSR author's certificate peck20-28 15. p ,, 692813, cl. S O B 35/5, 1977. Koks15-02.Avtorskoe certificate of the USSR Printed number 783366, cl. C 01 V 31/02, 1979 carbonoxide car- (prototype). Thermoanthracite Else