RU2327637C1 - Method of obtaining detonation nanodiamonds - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention is designed for industrial production of powders of detonation nanodiamonds, which can be used in obtaining abrasives, polishing compositions, strong and wear-proof compositions and coatings, adsorbents, biologically active compositions and semiconductors. The essence of the invention lies in that, a charge (with mass of 20-40 kg) from an alloy of trotyl with hexogene or octogene is exploded at the centre of a sealed explosion chamber, in which, prior to the explosion, several water jets are formed, moving in radial form from the walls of the chamber to the charge. The explosion takes place when the water jets, colliding around the charge, form a water envelope with mass not less than ten times the mass of the charge. After the explosion, the obtained suspension of nanodiamonds in water is pumped out of the chamber into a settling tank. After settling, the suspension is whizzed and undergoes purification from metal oxides and non-diamond carbon, or is dried.

EFFECT: higher output, lower cost of detonation nanodiamonds.

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Description

Technical field

The invention relates to industrial technology for producing superhard materials, namely highly dispersed artificial diamonds, or detonation nanodiamonds (DNDs), obtained from carbon molecules of explosives (BB) as a result of their detonation. Use of DND: obtaining abrasives, various high-strength and wear-resistant compositions and coatings, biologically active compositions, adsorbents, semiconductors.

State of the art

Physics and various technologies for obtaining DND are described in detail in the books of V.V. Danilenko “Synthesis and sintering of diamonds by explosion” (M., Energoatomizdat, 2003, 271 pp.), V.Yu. Dolmatova “Ultrafine detonation synthesis diamonds” (St. Petersburg, publishing house SPbSPU, 2003, 344 pp.) And A.L. Vereshchagin “Detonation nanodiamonds” (Barnaul, ed. Altai State Technical University, 2001, 176 pp. ), as well as in many journal articles since 1988.

Conditions for the formation of DNDs in a detonation wave: initial pressure values of more than 20 GPa and a temperature of 3500 - 4000 K when using explosives with a negative oxygen balance (in this case, the carbon of explosive molecules is released in free form). The conservation of DND is ensured by detonation of charges in a sealed explosive chamber (explosion locator) and due to the rapid cooling of the DND. Cooling is provided by one of the following methods: an inert gas atmosphere in an explosive chamber with a sufficiently large heat capacity, for example, carbon dioxide (Lyamkin AI, Petrov EA, Ershov AP, etc. Production of diamonds from explosives. DAN USSR, 1988, t.302, s.611-613; Petrov E.A., Sakovich G.V., Brylyakov P.M. Conditions for the conservation of diamonds in the process of detonation production.DAN USSR, 1990, t.313, No. 4 , p. 862-864), the water-droplet atmosphere created in the chamber (Danilenko V.V., Trefilov V.I., Danilenko V.N. patent SU 1813293 A3; Korobov D. Yu., Korobov Yu.A. patent RU 2049 723; Misonochnikov A.L., Rumyantsev B.V., patent RU No. 2036835) by the explosion of charges in water foam, in an aqueous or ice shell (the mentioned patent SU 1813293 A3, as well as Averin A.N., Filatov L.I. , Alekseev A.V. et al., Patent RU 2078661 C1). By the method described in US Pat. USA No. 5353708 (authors Stavrev S.Yu., Lazarev SB, Stoev KL and others), to get the DND, the explosive charge is immersed in any amount of water in the explosive chamber.

Historically, when the DND synthesis was discovered in 1963, a method was used to cool the DND by enclosing a charge in a shell made of water or various metals (Volkov K.V., Danilenko V.V., Elin V.I. Synthesis of diamond from carbon of detonation products of explosives. FGV, 1990, No. 3, p.123-125). It was experimentally found that, compared to the method, due to explosions in an inert atmosphere, the use of water or ice shells increases the yield of DND by about a factor of 2, up to 10-12% of the mass of the blast charge from an alloy of TNT with RDX with a TNT content of 40%.

In the article Vyskubenko B.A., Danilenko V.V., Liin E.E. et al. “The influence of the scale factor on the size and yield of diamonds during detonation synthesis”. FGV, 1992, No. 2, pp. 108-109, it is shown that the DND yield increases with increasing mass of the water shell, reaching a maximum at a mass of water equal to ten masses of the blast charge. Moreover, the DND output does not decrease with increasing charge mass.

As the closest analogue, the method for the industrial synthesis of DND was selected, described in the article by G. G. et al. "Industrial synthesis of detonation ultrafine diamonds and some areas of their application", ZhPKh, t.75, issue 5, 2002, p.773- 778. The largest DND yield relative to the mass of the explosive charge is achieved when the explosive charge is enclosed in a massive shell of water or ice.

For an industrial scale of production, the volume of synthesized DND exceeds 1 ton of DND per year. In known technologies, the synthesis of DND is carried out by undermining charges of 1-2 kg. With DND output of 10% of the charge mass for production, for example, 1 ton of DND per year, it will be necessary to manufacture and detonate 10,000 charges or 40 explosions per day in the chamber, which is almost impossible to do. It is feasible to produce 1 ton of DND per year using charges weighing 20 kg (2 explosions per day). However, for such charges to ensure a DND yield of 10%, shells of water or ice weighing 200 kg are necessary, which creates great difficulties in blasting. In addition, the production of disposable water containers is required (which pollutes the DND and requires additional costs for chemical cleaning of the DND) or 400 kg of ice per day (which requires a significant expenditure of electricity and time).

Thus, the known methods for the synthesis of DND are of little use for the industrial production of DND.

Disclosure of invention

The technical result of the present invention is the creation of an industrial technology for the production of DNDs with high productivity that reduces the cost of DNDs, which is ensured by the possibility of multiple explosions of charges from an alloy of TNT with RDX or HMX of large mass (20-40 kg) with DND cooling with water, but without making massive water or ice shells around the charges.

This is achieved by explosions in the center of the sealed explosive chamber of charges made of an alloy of TNT with RDX or HMX, and before the explosion, a lot of water jets are created in the chamber, directed radially from the walls of the chamber to the charge, and the explosion of the charge occurs after the colliding jets form around the charge water shell with a mass of at least ten masses of charge. In addition, the jets moving towards the center of the chamber fill the entire chamber volume and additionally cool the DND, as well as reduce the load on the chamber walls, since the energy of the explosion products is spent on quenching the kinetic energy of the jets and crushing them. As a result, the rates and pressures of the interaction of water and detonation products with DND with the surface of the steel walls of the chamber are significantly reduced, which leads to a decrease in the content of metal oxides in DND, which are the main content of non-combustible impurities (ash) in DND. The time interval between the beginning of the movement of the jets in the chamber and the detonation of the charge for this chamber and this charge is determined experimentally.

Example.

An explosive chamber with a volume of 350 m ³ has 128 pipes with a diameter of 2 "in the walls, the axes of which are directed to the center of the chamber. Some ends of the tubes are open and flush with the inner surface of the chamber, while the other ends are installed in an airtight tank with water. A charge from TNT alloy with hexogen (TG40 / 60) weighing 30 kg. For 3 seconds before the explosion, compressed air with a pressure of 10-15 atm is supplied to the tank, which displaces water into the pipes and creates 128 radial jets in the chamber that collide around the charge. the total mass of water in the chamber is 900 kg After the explosion, the DND suspension in water is pumped out of the chamber to the conical sump. After 30 minutes of sedimentation, the sediment from the sump is fed by gravity to a centrifuge or to a vacuum filter, where most of the water is separated from the bottom. carbon and metal oxides or dried.

A comparable analysis of the invention with the prototype shows that the inventive method for the industrial production of DNDs has new features that provide increased productivity and quality of DNDs, as well as lowering the cost of DNDs.

Industrial applicability

This invention will find application in the production of more than 1 ton of DND per year by the explosion in a water shell of cylindrical charges from a TNT - RDX (TG40 / 60) alloy weighing 20-40 kg with a DND yield of 10-12% by weight of the charge.

Claims (1)

A method for the industrial production of detonation nanodiamonds by explosion in the center of a sealed explosive chamber in the water shell of charges of an alloy of TNT with RDX or HMX, characterized in that a lot of water jets are created in the chamber before the explosion, moving radially from the walls of the chamber to the charge, and the explosion occurs at the moment when the jets colliding around the charge form a water shell with a mass of at least ten charge masses.