SU983043A1 - Carbon granulated filling - Google Patents

Description

The invention relates to the technology of burning carbon molding blanks used after graphitization in various fields of technology, in particular, in the production of quartz glass, for lining chemical equipment, and also in the form of graphite equipment of vacuum furnaces in semiconductor technology and others

Known carbon backfill used for burning carbon and graphite products. Anthracite, coke, sand, slags, etc. are used as backfill. Packing prevents the products from oxidation and adsorbs partially released volatile substances of the pitch during roasting. Backfilling is applied next

granulometric composition: fractions of 0.5 mm and 6 mm in order to reduce the sorption surface of the backfill and preserve the properties of the graphitized materialS J.

A disadvantage of the known backfill is ad hoc porosity, which reduces the density and strength of the products.

Closest to the present invention is carbon granular charge for burning carbon-graphite.

products containing granules fraction of 0.3-8 mm with a pore size, wt.%:

0.6-2 mm35-40

. 0.6-1.3 mm The rest with benzene sorption capacity 280 μm mol / g 2.

The disadvantages of the known backfill are a significant pore size in the granules, which reduces the strength and

10 density of carbon material, increased sorption of backfill volatile pitch, which also leads to a decrease in the strength and density of products and in 4 sintering of backfill, and as a result

15 its replacement after use in 2-3 firing processes.

The aim of the invention is to increase the density and strength of graphitized products.

This goal is achieved by the fact that carbon bedding for burning carbon-graphite products contains granules with a pore size at the following grading, mA: s. %:

0.3-0.8 mm 40-50 0.1-0.3 mm Else Additionally, backfill contains granules with sorption capacity

30 for benzene 150-240 microns mol / g. The use of the proposed charge with the specified distribution and pore size for the firing of carbon graphite and products allows to increase the density and strength of the graphitized material. With a deviation from the proposed limits, the strength and luminosity of graphitized products decreases. Backfill is used to bake coal graphite products in conventional ring type gas furnaces. At the bottom of the chamber poured a layer of backfilling of at least 200 mm. A series of blanks with a diameter of 150-400 mm and a height of 200600 mm are placed on the bed. The distance between the blanks is 8-12 mm. Then the lower p is filled with pouring material (granulated petroleum coke) and a second, set of blanks is established. Distance between rows 200-250 mm. The firing of the blanks is carried out in a gaseous environment of volatile spaces with a continuous rise of temperature at a rate of 3.1 degrees / hour to 11009s, s for 10 h. Graphitization of the billets is carried out up to 2400 ° C at a rate of 10 K / h and an exposure for 5 h. Particularly important in the formation of the physicomechanical characteristics of the carbon material during firing is the porous structure of the gravel and therefore her sorbts onna ability. The blanks that are in the kiln are visco-plating. At the same time, part of the binder passes into the pores of the charge, due to capillary forces, as a result of which the strength and density of the material decreases. In addition, backfilling with large pores (by the known method) actively absorbs volatile pitch, which are not involved in the process of secondary pyrolysis in the bulk of the workpiece. It also reduces the strength and density of the material. The use of low-porous backfill (with a pore size of 0.3-0.8 mm 70 wt.% And 0.1-0.3 mm ZOmas.%) Leads to defects due to cracks, to its fast coking and create great difficulties in the afterburning of volatile substances. volume of the camera. In order to reduce the size of large pores, carbon bedding is thermally treated in the hydrocarbon amongst), for example, in the EVSh-2500 furnaces to lOOO for 90-180 hours. to obtain graphite with certain physicomechanical characteristics. The size of the pores and their number is determined by the known method 3. Example. The calcined coke breeze fraction of 0.3-8.0 mm with a fraction of 0.3 mm no more than 8 wt.%, Is pre-heat treated in methane in an EH-2500 type furnace to 1000 ° C for 110 hours. After carbon impregnation, porosity backfilling is as follows: 0.3-0.8 and 0.10, 3 mm, respectively 30 and 70% by weight. The benzene sorption is 270 µmol / g. The granulated beding obtained in this way poured the layer onto the bottom of the chamber (Ridamer type furnace) 210 mm thick. A series of GMZ billet with a diameter of 200 and a height of 240 mm is installed on the filling. The distance between the workpieces is 8 mm. Then, the lower row is filled with interfacing material and a second row of blanks is installed, the distance between the rows is 200 mm, etc. The billets are fired in the gaseous environment of volatiles with a continuous rise in temperature at a rate of 3.1 deg / h to 1100 ° C, with a holding time at the maximum temperature for 10 hours. The graphitization of the blanks is carried out in industrial furnaces up to 2400 ° C in the filling of pitch coke at a rate of 10 deg / h and holding at a maximum temperature of 5 hours. EXAMPLE 2. It differs from Example 1 in the heat treatment time of the backfill in the EVSh-2500 furnace (140 hours) and its porous composition, in wt.%: 0.3-0.8 mm 40; 0.1-0.3 mm 60. The benzene backfill sorption by reducing the number of fine pores is 180 µmol / g. Example 3: It differs from Example 1 with a pyrocarbon backfill impregnation time of 170 hours, a benzene backfill sorption amount of 150 μmol / g, and its porous composition in wt.%: O, 3-0-, 8 mm 50; 0.1-0.3 mm 50. EXAMPLE 4. Differs from Example 1 by impregnation with pyrolytic carbon backfilling - 90 hours, the benzene sorption amount is 250 μmol / g, and its porous composition, in wt.%: 0.5t1.2 mm 40; 0.12-0.4 mm 60. P p and 1I e p 5. In example 1, rto impregnation with pyrocarbon backfill; 180 h, the magnitude of sorption of the benzene bedding is 140 μm mol / g, the porous bedding composition, wt .-% ;; 0.1-0.2 mm 50; p, 040, 07 mm 50. Comparative physicomechanical characteristics of the graphitized products obtained according to the invention (examples 2-4) and the known method are presented in table 1.

The composition of the size, pores of the bulk, wt.% Backfill, mm 1300.3-0.8 700.1-0.3 2. 400.3-0.8 600.1-0.3. 3500.3-0.8 500.1-0.3 4.450.3-0.8 55o, 1-0.3 5400.5-1.2 600.12 -0.4 6.500.1-0.2 500 , 04-0.07 735-400.8-2.0 known - 60-650.6-1.2 nye} "" L it .. Method of sorption on benzene 8 process of the study found that when grinding backfilling during roasting, porosity. The amount of backfill does not change. During firing, an additional heat insulating charge is used, in the process of graphitization according to Example 1 2 3 4. 5 6 71

.Table 1

Tensile strength,

Density kgf / cm g / cm g

when compressed with out of .1 bend C 240 1.70 180 1.76 150 1.80 170. 1.78 250 1.68 280 140 1.65 280 1.60-1.62 230-260 85-110 KKBMV translated to 4. 0 give chlorine to remove matter from impurities. Table 2 presents the density of green (unfired) blanks. And after firing. That 6 l and c and 2 Density of preparations, g / cm. Flax burned 1,701,61 1,711,64 1 / 691,68 1,691,67 1,691,59 1,681,49 68-1,701,50-1,52

From Table 2 it follows that the most preferable for the manufacture of graphitized products is Example 3, where the highest density and strength, as compared with lime and examples, are obtained, the entrance of the Go beyond the proposed limits. For example, the value of compressive strength and bending of the products obtained according to the invention is higher compared with the known, respectively, 50 and 72%, and the density is 11%.

Due to the higher parameters in terms of the density and strength of the products, the operation of the products obtained using the proposed carbon bedding is significantly extended.

Claims (4)

1. Carbon granular backfill for carbon dioxide of carbon dioxide graphite products, characterized in that, in order to increase the density and. jj the strength of the products, it contains granules with a pore size in the following ratio, wt.%: 0.3-0.8 mm 40-50 0.1-0.3 mm Else 2. Backfilling pop.1, I have the difference that it contains granules with a sorption capacity for benzene 150-240 microns mol / g. Sources of information taken into account in the examination 1. Chalykh E.F. Technology carbon and graphite materials. M., Metallurgists 1963, p. 207. 2.Tehprocess 19-72 graphite production GMZ Moscow Electrode Plant. M., 1972, p.44 (prototype). 3. Vutyrin G. M, High-porous carbon-graphite materials. M., Himi, 1976, p.43-49. 4. Bagrov G.N. et al. Benzene sorption on petroleum coke. Sat works No. 3 Graphite-based construction materials. M., Metallurgists, 1967, pp. 191-196.