SU1834845A3 - Method of producing high-melting titanium carbide-base compounds and device for its implementation - Google Patents

Description

The invention relates to the field of producing refractory inorganic compounds by the method of self-propagating high-temperature synthesis in the combustion mode, and in particular, to a technology for producing SHS-refractory compounds based on titanium (for example, SHS-titanium carbide) used as abrasive and magnetically abrasive materials in the form of powders, pastes, grinding wheels and as wear-resistant materials for spraying.

The purpose of the invention is to increase the yield of titanium carbide, increase its abrasive characteristics and reduce the fire and explosion hazard of the process.

This goal is achieved by the fact that the mixture of the starting components is compacted into a shell of graphite fabric, the synthesis is carried out with continuous evacuation of the reaction gases in an argon stream at a pressure of 1.21.5 atm, and the final product is also cooled in argon at a pressure of 1.1- 1.2 atm, and the ratio of the diameter of the discharge pipe to the diameter of the casing of the device is 1: 5-7.

The drawing shows a longitudinal section of a General view of a device for implementing the method.

The device comprises a cylindrical body 1 with a bottom 1 and a flange 3, in which there is a space for cooling the vacuum strip 4 with water; a cover 5, on which openings are located for accommodating reaction initiation means 6, nozzles for connecting supply systems

1834845 argon AZ and evacuation 7, installation of instrumentation 8, as well as protective shields 9.

In the center of the lid there is a discharge pipe of reaction gases 10. Coaxially to the housing 1, a shell 11 of graphite fabric TGN-2M is installed with a steel cylinder inserted into it for the charge loading period. Between. the housing 1 and the shell 11 is filling 12 layers of powder of the waste product of the final product,

The essence of the method and device for its implementation is as follows: on the bottom 2 of the device is placed backfill 12 of the waste powder of the final product.

Then, coaxially to the housing 1, a shell 11. is installed using a steel cylinder 11. of graphite fabric TGN-2M, into which a charge 13 is pre-dried and compacted, previously dried to a constant weight, and the layer of the waste product powder of the final product 12 is loaded and compacted into the space between the housing 1 of the shell device 1T.

After loading and compaction of a certain portion of the charge and backfill, the cylinder is lifted. Next, load and compact the next portion of the charge and backfill with the subsequent lifting of the cylinder. When compacting the upper layer of the charge, electrodes are brought into contact with it and the shell is tied. The cylinder is removed before synthesis.

Install the device cover 5, seal it, and with the upper shutter of the discharge pipe closed, evacuate and check for leakage.

Next, the device is filled with argon to a pressure of 1.1-1.5 atm and the cooling system of the housing, cover and discharge pipe are connected. Then they charge the mixture and carry out synthesis with continuous evacuation of reaction gases in an argon stream with constant cooling of the device in a special box by irrigation. At the end of the gas evolution process, the device is sealed, filled with argon to a pressure of 1.1-1.2 atm, and cooling of the snack of the final product is performed. Next, the device is depressurized, turned over and the shell is easily separated from the backfill along with the synthesized SHS product. The graphite fabric shell is separated from the cake and used in subsequent synthesis processes.

The increase in the yield of the product and the associated cycle productivity of the process occurs due to:

- increasing the depth of reaction, due to the close contact between the powder particles of the reaction mixture, which is compacted into a shell of graphite fabric, which prevents the separation of the charge with a large gas evolution and entrainment of particles with exhaust gases;

-reducing oxygen content of free carbon in the final product, due to the fact that the removal of reaction gases is carried out in an argon stream at a pressure of 1.1-1.5 atm, and the cooling of the final product also in argon at a pressure of 1.1-1.2 atm . Under these conditions, the rate of removal of carbon monoxide formed during the synthesis increases, the time of its contact with the cake of the final product decreases both during synthesis and during cooling in argon. At the same time, the depth of reaction 25 increases (the completeness of chemical conversion), the content of free carbon in the final product decreases, and its abrasive ability increases.

Reducing the argon pressure of less than 1.1 30 atm to oxidize the cake of the final product, increasing the oxygen content and free carbon in it, which reduces the yield and cyclic production. process duration.

An increase in argon pressure of more than 1.2 atm does not give a significant improvement in the quality of the final product: this increases the consumption of argon, which will affect the cost of the finished product.

π Example 1. For research, titanium powders of PTX grade of the Transcarpathian pilot metallurgical plant with a grain size of 3.0-0.4 mm are taken, which are subjected to mechanical activation for 8 hours. Of the 45 mass obtained, a 0.18 mm fraction is isolated, which is then used in all experiments. In this example, 80 kg of titanium powder with a fineness of 0.18 mm and 20 kg of carbon of technical grade PM 15TC are mixed for 20 hours. Next, the mixture is loaded into the device as described above and shown in Fig. scheme.

Then the device is sealed, vacuum, filled with argon, set fire to 55 charge and carry out synthesis with continuous evacuation of reaction gases in an argon stream with constant cooling of the device in a special box by irrigation. At the end of the gas evolution process, the device is sealed, filled with argon to a pressure of 1.1-1.2 atm, and the custody of the final product is cooled.

The synthesis pressure in the device varies from 1.0 to 1.5 atm depending on the ratio of the diameter of the discharge pipe to the diameter of the casing (from 1: 3 to 1: 8).

The pressure in the device when cooling the cake of the final product is created by supplying argon in an amount sufficient to maintain 1.1-1.2 atm.

• PRI me R 2.39.8 kg of titanium powder grade PTX Transcarpathian pilot metallurgical plant with a particle size of 0.18 mm 49.7 kg of iron powder of the ПЖРВ 3.200 brand and 10.5 kg of carbon powder of the technical grade ПМ 15Т are mixed for 20 hours.

The charge loading in the device, preparation for synthesis, synthesis and unloading of the device are similar to example 1.

After grinding the cake, for further studies, powders with a grain size of 500/63 are taken, which characterize the properties of the entire material, and not its individual fractions. Then carry out microscopic studies, determine the chemical composition, abrasive properties and yield of the product by known methods.

Comparative data obtained during the studies are shown in the table.

From the data presented in the table it follows that the highest yield of SHS product is observed when the reaction mixture is compacted into a shell of graphite fabric, the synthesis is carried out with the removal of reaction gases through a discharge pipe (the ratio of the diameter of the discharge pipe to the diameter of the device is 1: 5- 7) in a stream of argon at a pressure of 1.1-1.5 atm, and the cooling of the final product is also in an argon medium, adding 1.1-1.2 atm. At the same time, the quantity of the final product improves due to a decrease in the content of oxygen and free carbon, its abrasive ability increases, which makes it possible to achieve a higher roughness class at the same time.

The invention has the following advantages:

an increase in the utilization rate of the powders of the reaction mixture due to their compaction in a shell of graphite fabric, which eliminates the entrainment of particles into the atmosphere and increases the depth of reaction of the components of the mixture and yield

reduction in oxygen and free carbon due to the fact that the synthesis is carried out with continuous evacuation of reaction gases in an argon stream, and the final product is cooled in argon at a pressure of 1.1-1.2 atm;

increased yield of the product with an increase in its abrasive ability due to the design features of the device and optimal technological conditions.

simplicity and reliability of the device during its operation;

the possibility of using the invention to obtain magnetic abrasive materials based on titanium carbide.

Claims (2)

Claim 1. A method of obtaining refractory compounds based on titanium carbide, comprising preparing a mixture of powders of the elements making up the compound, compacting it, subsequent heat treatment in the combustion mode in a graphite shell during removal of reaction gases and cooling the resulting product, characterized in that, in order to increase the yield titanium carbide, increasing its abrasive characteristics and reducing the fire and explosion hazard of the process, heat treatment is carried out in a shell of graphite fabric with constant removal of reaction gas in a flow of argon gas at a pressure of 1.2-1.5 atm, and cooling is performed in an argon stream at a pressure of 1.1-1.2 atm. 2. A device for producing refractory compounds based on titanium carbide, including a cylindrical body with a sealed cover, an opening for accommodating reaction initiating means, nozzles for connecting vacuum systems and argon supply, and also a means for removing reaction gases, characterized in that, for the purpose of increasing the yield of titanium carbide, increasing its abrasive characteristics and reducing the fire and explosion hazard of the process, the means for removing reaction gases is made in the form of a centrally located lid tr boprovoda, provided in its lower portion under the lid protective screens, the ratio of its diameter to the diameter of the housing is 1: 5-7. 183 <845 eleven q φ ο ο ι t t co l 1 3X4- 1 I 1 1 I 1 X 1 m I 1 1 1 cr 1 1 X C4 Έ. · I 1 4 (J 1 fll U 4- 1 1 Li 1 Cl Rod I 1 c t • l SO E O U. 1 1 J nJ x υ x x 1 1 u t _l i I 1 about t 0) 1 1 1 1 X 3 1 ί X X ! *9 I 1 1 <11 1 flj 1 o 1 1 X 1 £ 1 I ! about 1 Q, • I ....... at 1 X 1 ¢) U 1 1 V f U 1 t 1 go 1 about <0 ι <4 1 1 t U X 1 about 1 ί X 1 I 1 1 CT 1 1 and t X 1 1 X 1 (0 1 1 Li t 1 J 1 fl) t > T 1 to r X 1 1 X t T <0 1 1 (Π 1 3 X i 1 Ct t 33 about 1 1 <0 t X ΓΣ 1 1 I X 1 4- co υ 1 1 1 1 1 t i 1 1 I 1 ί Ts I I Φ 1 co FH. 1 I X 1 fll X I- 1 1 X 1 n X s 1 Q Π4 f I 1 5 t 1 1 I X CO 5 1 1 f —I 1 ! 1 X ί Ci 1 1 about h fl) 1 1 1 Ω 1 1 J about I I 1 1 1 1 1 1 1 1 1 1 t fl> t I 1 Ts * t 1 t co f x 1 1 1 <0 X 4- i 1 1 ! ! c: X y 5 —I SP 1 1 co 1 X 1 1 f 1 L1 1 1 J- f Cj- "0 1 1 x t f <U 1 1 x f a H 1 1 CJ 1 and I ’X i 1 l> 1 1 1 m i eleven X O 1 ι m co 1 I n φ 1 1 Lt ’X 1 ι in about i 1 o X t X 1 1 and X t υ 1 1 o g about f 1 1 s l X X 1 1 1 ) about ! 1 and about about ABOUT 1L about ABOUT about 00 04 04 with | 04 04 04 ABOUT about 1 1L 1 1G4 * cl 00 with * 00 Um 04 04 04 ABOUT cn ♦ - 1 f X 3 1 f X 3 Ct X Ct X + · X X A about to A ABOUT a I and X about and X about about F = r η F = r w u X about X φ co u 3 X <0 F u Q. <0