RU2711599C1 - Method of producing detonation nanodiamonds - Google Patents

Abstract

FIELD: manufacturing technology.SUBSTANCE: invention can be used in electroplating, polymer chemistry, medicine, biology, as well as in production of oil and polishing finishing compositions. Composite explosive composition is prepared, containing the following components, wt%: tetryl 5–90; TNT 5–70; hexogen 5–45. Composite explosive composition is then blasted in an aqueous shell or shell containing 5 % aqueous solution of urotropin or Trilon B, with weight ratio of explosive composition and shell equal to 1:(10–14), in medium of gaseous products of detonation of previous detonations of explosive composition as non-oxidative medium.EFFECT: invention provides high-quality detonation nanodiamonds (DND) using simple technology with high output.1 cl, 4 tbl

Description

The invention relates to chemical technology, and, in particular, to the production of detonation nanodiamonds (DND). DNDs are currently widely used in electroplating, polymer chemistry, in the form of oil compositions, in polishing finishing compositions, medicine, biologists, etc.

The DND production technology is widely known for undermining a mixture of TNT and RDX ~ 50/50 [Danilenko V.V. Explosion: physics, engineering, technology / M: Energoatomizdat, 2010 .-- 784 p. - ISBN 978-5-283-00857-8; Staver A.M., Lyamkin A.I. Obtaining ultrafine diamonds from explosives // In interuniversity collection. “Ultrafine materials. Obtaining and properties ”, Krasnoyarsk, ed .: rotoprint KrPI. - 1990. - S. 3-22; Danilenko V.V. Features of the synthesis of detonation nanodiamonds // Combustion and Explosion Physics. - 2005. - T. 41, No. 5. - S. 104-116; Dolmatov V.Yu. Detonation nanodiamonds, production, properties, application. - St. Petersburg: NPO Professional, 2011-536 p., Ill., Uv. incl. ISBN 978-S-91259-073-3].

Known methods for producing DND using a large number of different explosives (BB), mixtures thereof, and with the addition of various inert (non-explosive) compounds [Staver A.M., Lyamkin AI Obtaining ultrafine diamonds from explosives // In interuniversity collection. “Ultrafine materials. Obtaining and properties ”, Krasnoyarsk, ed .: rotoprint KrPI. - 1990. - S. 3-22].

However, all these developments remained unclaimed due to low efficiency (low DND yield), scarcity and high cost of explosives, high risk of working with both individual compounds and their mixtures.

Nevertheless, there are huge unclaimed for direct use in ammunition, reserves of tetryl (N-methyl-N, 2,4,6-tetranitroaniline), which are currently not used.

The closest and only analogue (prototype) is the work of EA Petrova [E.A. Petrov, Study of the physicochemical processes of detonation synthesis of nanodiamonds, Collection of reports of the International Scientific, Technical and Methodological Conference December 22-24, 2004, Kazan, p. 881-888.

According to this method, a shell-free (without reservation) charge obtained from pure tetrile and a mixture of tetril (50%) and hexogen (50%) was blown up in an explosive storage chamber, while the DND yield was 4.1% wt. and 2.47% wt. respectively.

The disadvantages of the prototype are:

1. Low yield of DND (4.1 or 2.47% wt.), Which makes such production economically unprofitable;

2. Explosion of a shell-free charge with a strong shock action of gaseous detonation products (GPA) on the walls and shutoff valves of the chamber, which leads to severe corrosion of the chamber walls (and, accordingly, pollution of the diamond charge (AS) obtained immediately after the explosion with an excess of non-combustible impurities) . The amount of such impurities (metal oxides) can reach up to 30% wt. and more. Such an AS is unsuitable for processing into pure DNDs, especially for direct use in electroplating, polymer chemistry, oils and lubricants, and polishing compositions.

3. The difficulty of removing dry AS, deposited on the walls of the explosive chamber, at least 1/3 of AS is carried away with the gaseous products of the explosion.

The objective of the present invention is to obtain high-quality DNA by simple technology with a high yield of three-component charges, including tetryl.

The task is achieved by detonating composite explosive compositions in a non-oxidizing medium of the following composition (% wt.):

Tetrile 5-90 TNT 5-70 Hexogen 5-45,

wherein the explosive charge is carried out in an aqueous or in a shell containing a 5% aqueous solution of urotropine or disodium salt of ethylenediaminetetraacetic acid (Trilon B), with a mass ratio of explosive charge: shell = 1: (10 ÷ 14).

The oxygen balance (KB) of the three-component mixture is selected within the recommended range of KB -35 ÷ -65% [Dolmatov V.Yu. Assessment of the applicability of explosive charges for the synthesis of detonation nanodiamonds, STM, 2016, No. 5 (233), p. 109-113. / Dolmatov V. Yu., Assessment of applicability of explosive charges for synthesis of detonation nanodiamonds, Journal of Superhard Materials, September 2016, Volume 38, Issue 5, pp 373-376].

However, the process of obtaining DND is influenced, in addition to KB, by many other controlling factors:

1. The composition of the molecules of explosives and the class of compounds;

2. Charge density;

3. Power charge;

4. Detonation conditions: the presence or absence of a shell in the charge, the composition of the gas medium in the chamber, the form of the charge, the ratio of the mass of the charge and the volume of the chamber, the place of the charge detonation and the power of the initiating pulse, the material of the walls of the explosive chamber.

The charges were detonated in an Alpha-2M explosive storage chamber with a volume of 2.14 m ³ . Undermining was carried out in gaseous detonation products of previous explosions, in a non-oxidizing environment. The charge was placed in a plastic bag with 4-5 liters of H ₂ O or an aqueous solution of urotropine or Trilon B.

The use of an aqueous shell (for example, VV Danilenko, Explosion: physics, engineering, technology, M .: Energoatomizdat, 2010. - 784 p. - ISBN 978-5-283-00857-8) in the ratio of H ₂ O: BB = 4: 1 is known, the use of the shell in the ratio of H ₂ O: BB = 1: 6 is also known (Pat. RF No. 2348580, IPC СВВ 31/06, publ. 10.03. 2009). The effect on the detonation synthesis of a larger ratio of water or the specified solution is not known. The use of any tetrile reservation, including water and the indicated solutions, is not known.

The use of three-component charges is possible only after a mandatory study of mixtures with tetrile, their thermal stability, chemical resistance, sensitivity to shock and friction.

Tests for thermal stability (in non-isothermal conditions) were respectively carried out on a Q-derivatograph (upgraded). The type of sample holder is a quartz crucible with an internal notch for a thermocouple (diameter 8 mm, height 12 mm), the type of thermocouple is platinum-platinum rhodium (rhodium content 10%), the test medium is air, without pumping. The heating rate is 5 ° C / min, the temperature range is 20-500 ° C.

where T _HP - the temperature of the onset of decomposition;

T _nir is the temperature of the onset of intense decomposition.

Conclusion: the conclusion about the compatibility of tetrile, trotyl and hexogen can be made only by the results of studies on the measuring and computing complex "Volcano - 2000" (chemical resistance).

Conclusion: based on the results obtained, it is clear that the mixture is compatible and the charge can be obtained by pressing.

Determination of the sensitivity of explosive materials to mechanical stress

Sensitivity to shock was determined according to GOST 4545-87 on the K-44-II head, load weight 10 kg, roller device No. 1; sensitivity to friction was determined according to GOST R 50835-98 on the K-44-II head, load weight 1.5 kg, temperature 20 ° C.

Conclusion: the addition of tetrile to the composition of explosives does not significantly affect the sensitivity to mechanical stress. The charge can be made by pressing.

The difference in the technologies for obtaining DND and, especially, in the composition of explosives, strongly affects the properties of nanodiamonds. It can be consistently argued that at present there is no single material called "detonation nanodiamonds." There is no single quality certificate for DNDs; it is also not known which parameters (properties) of various DNDs are crucial for such a still new type of nanomaterial. The main factors determining the yield and quality of the DND are the explosive charge composition, charge armor (shell) and the composition of the gaseous medium in the explosive chamber.

At present, it is not necessary to confirm the initial clarity of the results of detonation of an explosive charge even with knowledge of the main control parameters of the process, including because of the non-ideal detonation process. Moreover, it is still unknown which reactions and in what sequence occur behind the detonation wave front in the zone of chemical reactions (ZHR). This is understandable: there are no methods, apparatus, and instruments for determining the real kinetics of the explosive decomposition process, taking into account the reaction time of 0.1 MKS (10 ^-7 s), a temperature of ~ 4000 K and a pressure of ~ 250,000 atm.

The composition of chilled detonation products (PD), including solid carbon, cannot be calculated without experimental implementation.

So, for example, the undermining of the now most common for obtaining DND non-shell cast charges of TG 50/50 in the work [Staver A.M., Lyamkin A.I. Obtaining ultrafine diamonds from explosives // In interuniversity collection. "Ultrafine materials. Production and properties", Krasnoyarsk, ed .: rotoprint KrPI. - 1990. - S. 3-22.] Gave the yield of DND at 0%, and in [Babushkin A.Yu., Lyamkin A.I. , Staver AM Features of obtaining ultrafine carbon-based material from explosives // In the collection of reports of the V All-Union Conference on Detonation, Krasnoyarsk, August 5-12, 1991. - 1991. - T. 1. - P. 81-83 .] - yield 8% wt.

Water-based charge reservation is used to quickly cool PD to temperatures below which graphitization of already obtained DNDs does not occur (from ~ 4000 K to ~ 1300 K). However, here the effect of the composition of the reservation is also far from clear. So, in [V. Yu. Dolmatov, A. Vehanen, V. Myllymaki, A.S. Kozlov, T.T.B. Nguyen Influence of the composition of the charge reservation on the output of nanodiamonds and the content of impurities // Journal of Applied Chemistry, vol. 91, no. 2, 2018, S. 211-216.] Undermining the composition of the TG 50/50 in pure water gives a DND yield of 4.9% wt. The introduction of urotropine into water increases the yield of DND to 6.9% wt., But the introduction of Trilon B dramatically reduces the yield of DND to 3.37%. At the same time, according to this application, when using tetrile in a reservation from pure water, a high yield of DND is 6.32-7.36% wt., In aqueous urotropine the yield of DND is almost the same - 6.84-7.05% wt., And in an aqueous solution of Trilon B, the yield of DND is also high - 6.93-7.11% wt., that is, the data are completely different when compared with the previous example. Thus, it is impossible to predict the result in advance.

The non-ideal detonation, for example, for TG 40/60 charges, leads to the fact that, in contrast to calculations, the amount of CO ₂ generated (which should be ~ 100%) is actually ~ 30%, and CO ~ 70%. All this leads to a significant decrease in the yield of AS and DN [Kuzmin IG, Lyamkin AI, Staver AM Experimental study of the composition of the gaseous detonation products of condensed explosives in various atmospheres // In interuniversity collection. "Ultrafine materials. Obtaining and properties", Krasnoyarsk, ed .: rotoprint KrPI. - 1990. - S. 23-28.].

Thus, no theoretical constructs can describe the yield of DND depending on the conditions of its synthesis without its practical implementation. Nobody has studied the preparation of DND from triple compositions, especially tetryl-based compounds. The triple composition introduces even greater uncertainty in contrast to pure tetrile and binary charges.

The use of triple charges to obtain DND, especially with tetryl, is unknown.

Analysis of the data in Table 4 shows that the DND output within the claimed ranges of components and the reservation ratio fit into ~ 6.0 ÷ 8.2% wt., Which indicates a high cost-effectiveness of the method (a cost-effective way to obtain DND is if the yield exceeds 5% wt. .). There is a high stability of the yield of DND (> 6.0%) regardless of the content of the components within the stated ranges. And the content of non-combustible impurities of purified DNDs strongly depends on the reservation of charges, the minimum amount of non-combustible impurities is in DNDs obtained when booking charges with an aqueous solution of urotropin and Trilon B (the largest difference is up to 4 times). This makes such DNDs much more preferable for a number of areas of use, and sometimes the only possible ones, for example, DNDs in experiments No. 3, 6, 10, 11, 13, and 14 for medicine and biology.

From data comparison op. 3 and 15, op. 9 and 16, op. 13 and 17, it can be seen that an increase in the charge ratio has almost no effect on the output of DND, AS and the content of DND in AS. That is, a further increase in the explosive charge ratio: the reservation is not advisable - the consumption of the reservation increases without a visible effect.

The DND content in AS is also of great importance, both for subsequent chemical cleaning (the higher the DND content in AS is the lower the load on the sensitive stage of chemical treatment and less environmental damage), and for the subsequent use of AS itself (electroplating, oil and lubricants, polymer chemistry).

The use of a charge shell makes it possible to increase the DND output by a factor of 2–3 due to the rapid removal of heat from the explosion products — by evaporation of water, i.e. the graphitization of already formed DND particles decreases.

The presence of complexones (urotropine and Trilon B) translates some of the non-combustible impurities (metal oxides) into complex compounds that are readily soluble in water, which positively affects the result of chemical cleaning of DNDs. The content of non-combustible impurities in the DND drops 2-6 times. In addition, the presence of reducing agents in water (including urotropin and Trilon B) during decomposition during an explosion creates not a weakly oxidizing, but a reducing environment in the chamber, which also leads to an increase in DND yield and a decrease in the surface defects of DND layers. This, in turn, increases the possibilities of using DND in various fields, including medicine and biology. Explosion energy is spent on the breakdown of urotropin and Trilon B, while also allowing the graphitization of the resulting DNDs to be reduced.

A new version of the synthesis of DND from a three-component mixture containing at least 5% wt. tetrile, highly profitable, easy to process.

The residual cost of tetrile is very small, this raw material is available in huge quantities, further storage of tetrile is dangerous - tetrile is a fairly highly sensitive substance and its stability decreases with further long-term storage, which can lead, among other things, to an environmental disaster. In addition, the undermining of three-component charges in an aqueous or aqueous-salt medium can reduce the corrosion and impact on the walls of the explosive chamber, reducing the amount of non-combustible impurities in the AS and DND and increasing the life of the chamber. This makes the resulting products highly competitive.

The aqueous suspension of ASh is easily removed from the explosive chamber through the lower hatch and fed for further processing. The output of AS is in the range of 13-16% wt.

The essence of the method is illustrated by examples of its implementation.

Example 1. The pressing pressure of the three-component charges with tetrile was used from 1400 to 2000 kg / cm ³ .

The mass of the charge is 500 g, the shape is a cylinder having a diameter of 60 mm and a height of ~ 110 mm.

For the synthesis of AS and DND, an explosive chamber with a capacity of 2.14 m ³ Alfa-2M (Russia) was used. Charges were suspended in the center of the chamber in a reservation made of water or an aqueous solution of urotropin or Trilon B and undermined. The liquid reservation was poured into a regular plastic bag, the charge was immersed there and hung on a hook welded to the top loading hatch of the camera. The ratio of explosives: H ₂ O (or solution) = 1: (10 ÷ 14). The ratio of the mass of explosives to the mass of urotropine or Trilon B ~ 1: 0.5.

After each 5th blasting, a valve was remotely opened at the bottom of the chamber, and an aqueous suspension of ASh under slight pressure in the chamber flowed into the receiving tank (40 liter can). The resulting suspension of AS was filtered from coarse impurities, then from smaller impurities, subjected to magnetic separation and squeezed from excess H ₂ O in an industrial centrifuge. The ASh paste obtained after pressing (H ₂ O content of 75-85% wt.) Was sent to the washing stage. The washing of AS from water-soluble impurities (mainly complex salts of urotropine or Trilon B) was carried out in capacitive reactors (250-500 l), the ratio of dry AS to water = 1: 20 ÷ 40. Typically, 4 washes with cold water (~ 20 ° C) and 2 washes with hot water (~ 80 ° C). Further, the AS was dried on stainless baking sheets at (~ 130 ° C, and when a very thick mass formed, the temperature was raised to 160 ° C (without vacuum). If the charge was reserved with pure water, then the AS was usually not washed, but dried immediately.

The dried AS was crushed, triturated and classified on sieves with a cell of ~ 200 μm. Further, the AS was sent for analysis - the amount of oxidizable carbon was determined (by titration with K ₂ Cr ₂ O ₇ in conc. H ₂ SO ₄ ) and the amount of non-combustible residue was determined by burning the AS sample at 600 ° С, and for chemical treatment (57% nitric acid , t = 230 ° C and p = 80-100 atm).

All experiments are presented in table. 4 are made as described in Example 1 above.

Industrial applicability.

The development of the use of tetrile-based triple formulations was carried out for industrial use. The quality of the obtained DND is very high and a significant demand is expected for “tetrile” DNDs for electroplating (Cr-, Ni-, Zn-, Cu-, Ag-, Au-coatings, anodic oxidation from DND); for polymer chemistry, including adhesive systems; for superfinishing polishing, oil compositions; for biology and medicine.

Claims (3)

A method of producing detonation nanodiamonds by detonating a composite explosive composition containing tetryl, characterized in that the composite explosive composition consists of the following components, wt. %: Tetrile 5-90 TNT 5-70 Hexogen 5-45, in this case, the composition of the explosive composition is detonated in an aqueous shell or a shell containing a 5% aqueous solution of urotropin or Trilon B, with a mass ratio of the charge of the explosive composition and shell equal to 1: (10-14) in the atmosphere of gaseous detonation products of previous explosives as a non-oxidizing medium.