RU2712551C1 - 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. Individual explosive, which is represented by tetryl, is exploded in an aqueous shell or shell containing 5 % aqueous solution of urotropin or Trilon B, with weight ratio of explosive charge to shell equal to 1:(10–14), in medium of gaseous products of detonation of previous detonations of explosive charge 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, namely, 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, biology, 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.

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

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. In this method, without a shell (without reservation), the charge obtained by pressing tetrile with p = 1.61 g / cm ³ is blasted in an explosive combustion chamber and a DND yield of 4.10% wt. from the original tetrile

The disadvantages of the prototype method are:

1) Low yield of DNA (4.1% 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. In addition, at least 1/3 of the 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 tetrile.

The task is achieved by undermining the pressed tetrile charge (ρ> 1.6 g / cm ³ ) in an aqueous or shell containing a 5% aqueous solution of urotropine or disodium salt of ethylenediaminetetraacetic acid (Trilon B), with a shell: tetrile mass ratio = (10 -14): 1.

A compressed tetrile charge may be used.

Tetrile has an oxygen balance of -47.4%, which is ~ in the middle of the recommended 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. Specific power of charge;

4. Detonation conditions: the presence or absence of a shell on the charge, the composition of the gas medium in the 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 (disodium salt of ethylenediaminetetraacetic acid). Gas blasting (without charge reservation) was carried out by suspending the charge in the center of the explosive chamber. Undermining was carried out remotely.

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 N ₂ O: BB = 4: 1 is known. It is also known to use the shell in the ratio of H ₂ O: BB = 1: 6 (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 these solutions is not known. The use of any tetrile reservation, including water and stained solutions, is not known.

An analysis of the data in Table 1 shows that individual explosives, as a rule, give a very low yield of DND (~ 1% in the case of detonation of RDX, op. 1 and TNT, op. 2) even if they are detonated in a water reservation.

A gust of tetrile charge without reservation, in a gaseous medium from previous explosions, contrary to prototype data, did not yield 4.1% wt., But an insignificant yield of 0.76% wt., And led to an abnormally low yield of ASh - 0.97%, and anomalously the high content of non-combustible impurities in the AS is 51.54%, which makes such a method of undermining and obtaining AS and DND completely meaningless.

Undermining tetrile in the water shell dramatically increases the yield of DND. However, the ratio of shell mass to charge plays a significant role. So, in experiments 4-6, we observe a significant increase in the yield of DND with an increase in the BB: H ₂ O ratio from 1: 4 to 1:14. The yield of DND increased by 1.5-1.9 times, which is very significant. From comparison op. 6.7 and op. 12, op. 8.9 t op. 13, op. 10, 11 and op. 14 it can be seen that an increase in the tetrile: armor ratio to 1:15 has almost no effect on the yield of DND, AS, and the content of DND in AS. That is, a further increase in the ratio of tetril: booking is not practical - the consumption of booking is increased without a visible effect.

It is very important for the subsequent use of ASh and for chemical cleaning that the content of DND in ASh is very high - from 51 to 63% wt. The high yield of AS and the relatively low content of non-combustible AS impurities associated with it contributes to the low content of these impurities in DNDs from 0.4 to 0.9% by weight, which makes it possible to use these DNDs in various application technologies, including microelectronics, biology, and medicine .

The introduction of tetrile charges into the water (op. 6, 7) and the water-salt shells (op. 8 and 9 with urotropin and op. 10, 11 - with Trilon B) with the ratio of armor: tetrile = (10 ÷ 14): 1 give abnormally high yield of individual compounds, an average of 6.94% wt.

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 a 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 unambiguous. 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. So, according to the prototype, the yield of DND from a shell-free charge from tetrile was 4.1% by weight, and the repetition of this experiment in exact accordance with the prototype gave the yield of DND of ~ 0.76% by weight, that is, 5.4 times less. At the same time, the result of the authors of this application was also unexpected - the yield of DNA was up to 7.36% wt. with a blast in the water shell (10 times higher than with a blast without a shell).

A new version of the synthesis of DND from tetryl is highly profitable, simple in technical design. 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, undermining tetrile in an aqueous medium reduces the 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 most important indicator for further use of DND is the amount of non-combustible impurities, which are formed a little when using water or water-salt reservation - 0.37 ÷ 0.88 wt.%, Which allows the use of such DND for any application, including in medicine and biology.

The yield of AS is fairly stable - ~ 11.5 ÷ 12.0% by weight, if the amount of non-combustible impurities does not exceed ~ 4.0% by weight, then such AS can be used in electroplating, oils, and polymer chemistry.

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

Example 1. Before deciding on the possibility of using a monoproduct of tetrile, it is necessary to check its thermal, chemical resistance, sensitivity to shock and friction. Only after obtaining the relevant data can one come to a decision about the option of forming a charge — by melting or pressing, or about the impossibility of using this type of explosive in principle.

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 beginning of decomposition;

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

Conclusion: the data of Table 2 is not enough, research is needed on the Vulkan-2000 measuring and computing complex (chemical resistance). Tests for chemical resistance.

Thermal stability (chemical resistance) of explosive materials is determined by gas evolution in mm. Hg at the Vulkan 2000 measuring and computing complex at a temperature of 110 ° C for 14 hours without taking into account the pressure for the first hour of heating (average value of 3 ^x parallel experiments).

Conclusion: a charge of pure tetrile can be obtained by pressing, it is distinguished by high chemical resistance.

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: tetrile has almost the same sensitivity to mechanical stress as the classic TG-50 charge, which is widely used to obtain DND. Tetrile charges can be made by compression.

The pressure of pressing tetrile into charges was used from 1400 to 2000 ^kg / _cm ² . The weight of a standard charge is 500 g, 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 an ordinary 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 a 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 (the content of Н ₂ О 75-85% by mass) 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 ° С and p = 80-100 atm.).

All experiments are presented in table. 1, op. 6-11, performed according to the above procedure in example 1.

Industrial applicability.

The development of the use of tetryl was made 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 (1)

A method of producing detonation nanodiamonds by detonating an individual explosive, characterized in that tetryl is used as an individual explosive, while blasting is carried out in an aqueous shell or shell containing a 5% aqueous solution of urotropine or Trilon B, with a mass ratio of explosive charge substances and shell, equal to 1: (10-14), in the environment of gaseous detonation products of previous explosives as non-oxidizing medium.