WO2024042390A1

WO2024042390A1 - Safe initiation of shock tubes (nonel) connected to mineral detonators based on nanotechnology

Info

Publication number: WO2024042390A1
Application number: PCT/IB2023/057327
Authority: WO
Inventors: Esmaeil AYOMAN
Original assignee: Ayoman Esmaeil
Priority date: 2023-07-18
Filing date: 2023-07-18
Publication date: 2024-02-29

Abstract

A detonator without primary explosives includes: a closed side and an open side made of aluminum, Nanocomposite or micro-composite as the main charge, a steel cylinder containing a PETN compound with a density of about 1.1 g/cm3 and a mixture containing 80% of the PETN compound, 10% potassium perchlorate, and 10% potassium picrate with a density of about 1.5 g/cm3, a cylinder made of zinc metal filled with delay element, an isolated and a shock tube. A small amount of nanocomposite or microcomposite containing the combination of RDX and Nano thermite or micro thermite with a density around 0.45 g/cm3 without primary explosive causes a decrease in the strength and speed of the secondary explosives.

Description

Safe initiation of shock tubes (Nonel) connected to mineral detonators based on nanotechnology

A detonator without primary explosives consisting of one open side and one closed side metallic shell, includes the following components:

A closed side and an open side made of aluminum,

Nanocomposite or micro-composite as the main charge,

A steel cylinder containing a PETN compound with a density of about 1.1 g/cm3 and a mixture containing 80% of the PETN compound, 10% potassium perchlorate, and 10% potassium picrate with a density of about 1.5 g/cm3. the weight percentages of Al, CuO, and RDX compounds can be in the range of 10-50, 50-90, and 60-95 respectively for nanocomposite, but for micro-composite, the weight percentage of Al and CuO compounds in micro thermite (Al+CuO) should be 20 and 80, respectively, and also the weight percentage of RDX compound in nanocomposite or RDX+Al+CuO micro-composite should be 90 and the weight percentage of Nano-thermite or micro thermite (Al+CuO) in the desired nanocomposite is chosen equal to 10 so that it has been determined that the heat released from the micro-composite is higher than the pure RDX composition, which helps the better initiation of the nanocomposites.

F42B3/16 - C06C7/00

Detonator for shock tube connector system

United States Patent 6349648

A shock tube connector system comprises a substantially cylindrical detonator having a longitudinal axis a block body receiving the detonator therein, and an end cap. The detonator includes an axisymmetric exterior shell including a cylindrical main section, a cylindrical explosive end portion having a diameter less than the diameter of the main section, and a transition portion connecting the main section and the explosive end portion of the shell. An explosive charge is contained within the explosive end portion of the shell and is distributed along the longitudinal length of the explosive end portion. The explosive charge preferable comprises two portions of lead azide or a first charge portion of lead azide and PETN and a second charge portion of PETN. An initiating shock tube is operatively connected to the explosive charge via a delay element. The block body includes a housing within which the main section of the detonator is received. A tube holder connected to one end of the housing includes a base member having a bore within which the explosive end portion of the detonator is received. The tube holder is T-shaped and includes a pair of engaging flanges spaced from the base member on laterally opposite sides of the base member to define there between pair of engaging slots extending parallel to the longitudinal axis of the detonator and alongside the explosive end of the detonator received in the bore. Each engaging slot is adapted to frictionally grip at least four shock tubes alongside the explosive end of the detonator with the longitudinal axes of the shock tubes substantially orthogonal to the longitudinal axis of the detonator. The end cap is connected to the other end of the housing and secures the detonator within the block body.

Blast initiation device

United States Patent Application 20020162473

A detonator device and assembly for the initiating a plurality of signal transmission lines with a pressure impulse. The detonator device comprising a detonator casing having a signal receiving end and a firing end. The firing end of the detonator device being substantially shaped to conform with the pressure impulse initiation therein. The firing end having a contact wall of substantially uniform thickness for contacting a plurality of signal transmission lines in a compatible connector element and transmitting a pressure impulse thereto.

The combination of primary explosives, such as lead azide in this type of detonator is a standard but unsafe compound, as primary explosives - like lead azide, etc. according to Robert Matyáš et al.’s book “Primary Explosives (1st edition)” published in Springer-Verlag Berlin-Heidelberg (2013), are extremely sensitive.

As a result, any patents in removing this compound from the mineral surface detonator are presented here to discuss later. All the percentages are weight materials.

A kind of non-priming hole-by-hole initiation earth's surface detonator and installation thereof and using method

CN104897011B

A kind of non-priming hole-by-hole initiation earth's surface detonator and installation thereof and using method, relate to engineering explosion technical field, including body, interior cap, low power explosive charges, delay element, plastics connection plug and detonator, interior cap, low power explosive charges, delay element and plastics connection plug are sequentially loaded into tubular body, and detonator loads in plastics connection plug. This detonator is ignited delay element by 2 detonators, the low power explosive charges exciting interior cap is exploded, ignite 4 detonators bottom cap in body outlet insertion body, wherein 2 detonators ignite two Nonel detonators in big gun hole, another 2 detonators ignite a hole-by-hole initiation earth's surface detonator in next big gun hole, the like, and then realize hole-by-hole initiation. This detonator structure is simple, low cost few without priming, explosive payload, produce and use safety, detonates and propagation of explosion is reliable, and the earth's surface detonator cost solving prior art is high, the problem producing and using danger. The advantage of the present invention is the lack of the use of oxidation compounds such as KNO₃, KClO₃, and KClO₄in the main charge. These compounds can produce a strong toxic gas at the surface of the mines during the detonation. These toxic gases are extremely hazardous to personnel working in mines.

A kind of new low power basal detonator and preparation method thereof

CN103804104B

The invention discloses new low power basal detonator of one kind and preparation method thereof, the present invention be in order to meet both at home and abroad for earth's surface delay detonator the need for, for the research and development that one of the difficult point basal detonator of earth's surface delay detonator is carried out. It includes flat shell, a dress powder charge, two dress powder charges, strengthening cap. New low power basal detonator of the invention is on the premise of satisfaction reliability excites detonator; effectively reduce the power of detonating capsule; avoid its bottom metal jet; effectively protect blasting network; prevent destruction of the earth's surface delay detonator to networking; the reliability of explosion is improved, so as to realize accurate hole-by-hole initiation. The present invention is using aluminum horizontal bottom shell, eliminate the sockets for collecting energy that common shell has, not only simplify production technology, and the metal jet of detonator bottom can be prevented effectively from, simultaneously with the powder charge of unification dress, two dress powder charges, make new low power basal detonator brisance of the invention far below No. 8 detonators, be prevented effectively from the destruction to periphery Nonel tube network. The advantage of my invention compare to this invention is not using the DDNP compound, since the sensitivity of this compound is in the sensitivity range of the lead azide.

Low-strength detonating blasting cap

CN202938723U

The utility model discloses a low-strength detonating blasting cap, which comprises a cap casing and is characterized in that a main charging box body, a safe detonating body, a delay element, a rubber plug and a detonating tube are arranged from bottom to top sequentially in the cap casing; and the lower end of the detonating tube is inserted in the rubber plug. The low-strength detonating blasting cap has a simple structure and convenience in use, by means of the arrangement of the delay element, the length of the delay element can be adjusted according to the networking blasting time so as to meet the requirement of networking blasting; simultaneously, no primary explosive contains in the cap casing, the strength is small while the safety performance is high; and further fragments generated by the explosion are few, and the fragment energy is low, so that detonating network of detonating blasting cap cannot be cut. The low-strength detonating blasting cap solves the technical problems of low safety performance, poor entire explosive effect and unsuitability of networking explosion in the prior art.

Unleaded delay Nonel detonator

CN201993051U

An unleaded delay Nonels detonator belongs to the field of blasting supply for civil use, which comprises a tube. The unleaded delay Nonels detonator is characterized in that a high explosive, a primary explosive, a delay element and a seal plug are sequentially arranged in the tube. A Nobel tube is disposed in the seal plug and connected to the delay element which consists of an aluminum tube and delay powder filled inside the tube, and a plastic layer is laid on the outer surface of the aluminum tube. The unleaded delay nonel detonator avoids environmental pollution caused by heavy metal lead, enhances delay accuracy of a delay nonel detonator and lowers the cost of a nonel detonator. Meanwhile, the delay nonel detonator can be produced either in an integral structure or in a split outside-delay structure, and delay time is not affected by the tube length of a plain detonator and can be greatly prolonged so as to meet the requirements of specific users.

Detonator

CN103896696A

The invention discloses a detonator. The detonator comprises a detonator body and a core explosive, and is characterized in that the core explosive comprises the raw materials of cyclonite and aluminum powder in the weight ratio of 67: 33, as well as graphite which accounts for 0.3% of the total weight of the raw materials. The invention further discloses a manufacturing method of the detonator. The detonator can be widely applicable to inner and outer-layer surface detonators and in-hole detonators in non-electric detonation systems, and the product has the advantages of good tensile strength, flexural strength, temperature resistance, water resistance and oil resistance.

Detonation of explosives

WO2007110819A1

This invention relates to a time delay element, for use in a chemical detonator, the time delay element including an assembly, in a tubular casing having open ends, of : a timer charge made of a timing composition; a sealing charge made of a pyrotechnic material at one end of the timer charge, in contact therewith and in sealing contact with the inner surface of the tubular casing; a priming charge in contact with the end of the timing charge opposite the sealing charge; and at least part of a base charge being in contact with the end of the priming charge opposite the timer charge. The invention also extends to a chemical detonator including such a time delay element, and it extends, further still, to a method of manufacturing such time delay elements.

Non-primary detonator

CA2252353C

Deflagration to detonation transition (DDT) detonators are provided which are essentially free from primary explosives. The detonators utilize an intimate mixture of a large particle sized porous, powdered explosive such as PETN, and smaller particle size, high-burn-rate, pressurizing initiator such as a mixture of potassium picrate and potassium perchlorate. The smaller particle sized pressurizing initiator is located within the interstitial spaces of the larger powdered explosive. This mixture is able to reliably initiate an adjacent transition portion, or base charge while reducing the need for heavy confinement. The mixture can also be used directly in surface detonator applications. Improved performance and safety during manufacture of detonators is achieved.

Detonators comprising a high energy pyrotechnic

CA2215892C

In-hole and surface detonators are provided which are essentially free from primary explosives. The detonators utilize a high energy pyrotechnic mixture of a fuel and an oxidizer for initiation of a base charge enclosed in the detonator, or for the initiation of adjacent shock tubes. Improved safety during manufacture and use of detonators is achieved.

The advantage of the present design compared to this invention is the lack of using ammonium perchlorate, since at the time of initiation this compound produces lots of toxic gas. This invention compared to other inventions does not use the high amount of aluminum in the base charge, because the high quantities of this metal creates hazards in the mines such as coal. The other advantage of the present design compared to this invention is that it does not use PETN secondary explosive, because it has higher sensitivity compared to RDX.

During past years, Orica Explosives Technology Pty Ltd has produced a variety of products from surface and in-hole mineral detonators. Two products of surface detonators of this company called Exel HANDIDET and Exel HTD are the main products of the company and despite the patents (CA2215892C and CA2252353C) that the company has registered in the field of the surface detonator without primary explosives, still the compound of lead azide is used in them, which is probably a sign of poor performance of the presented products in those inventions.

Leo et al. in 2021 in article printed in Defence Technology journal, showed that when Nano thermite Al+Fe₂O₃ with different weight percentages of 1, 5, 10, and 20 is added to RDX, Nano thermite reduces the final detonation velocity of pure RDX from about 7500 m/s to about 5500, 4300, 3500 and 6000 m/s, respectively. According to the reached detonation velocity for these nanocomposites, it is clear that the detonation velocity, according to Robert Matyáš et al.’s book “Primary Explosives (1st edition)” published in Springer-Verlag berlin-Heidelberg (2013) (detonation velocity of lead azide compound equals to 4550 m/s) is approximately in the range of the detonation velocity of the lead azide compound and so it is clear that these nanocomposites can be used instead of lead azide in surface detonators.

According to Robert Matyáš et al.’s book “Primary Explosives (1st edition)” published in Springer-Verlag berlin-Heidelberg (2013), the article printed by Qingping Luo et al. in the journal of Materials 2018, 11, 1930, the article of Zehua Zhang et al. printed in the journal of Combustion and Flame 240 (2022) 112024, the article of Jingjing Wang et al. printed in the journal of Ceramics International 48 (2022) 20825–20837, and also an article printed by Zhiqiang Qiao et al. in the journal of Composites Science and technology 107 (2015) 113 – 119, it is determined that nanocomposites or microcomposites compared to primary explosives are less sensitive to impact, friction, and electrostatic discharge.

Some parts of the present work are presented according to the invention CA2252353C that was presented in 1998 by Orica Explosives Technology Pty Ltd, but the last part of the surface detonator contains nanocomposites or microcomposites.

According to the patent number CA2215892C in 1996 by Orica Explosives Technology Pty Ltd, the test for sensitivity to shock wave of surface detonators was designed.

According to invention CA2215892C in 1996 by Orica Explosives Technology Pty Ltd, by the fall of a steel weight, sensitivity of impact to surface detonators was designed.

According to Anthony Peter Gordon Shaw’s book of Thermitic Thermodynamics, published in CRC Press Taylor & Francis group - 2020, to achieve the highest adiabatic temperature in the oxidation-reduction reaction from Nano thermite or micro thermite to provide energy and heat to raise the assurance of Nonels initiation, special percentages combinations for each fuel and oxidizer should be used.

Copper oxide nanoparticles were synthesized according to the published paper by Murendeni P. Ravele et al. titled “Results in Engineering” 14 (2022) 100479, using the sol-gel method.

The safe initiation of shock tubes (NONEL) connected to mineral detonator based on nanotechnology, by surface detonator in mines are very important. Common surface detonator contains primary explosives such as lead azide. The surface detonator containing primary explosives are used to initiate the five Nonels connected to the detonator placed in the holes due to the lower power and detonation velocity compared to high explosives. Primary explosive such as lead azide are highly sensitive and polluting the environment, so that the production of these materials as well as the assembly and use of detonator containing these materials have serious problems so special condition is necessary to use them. To solve this problem, the strength and detonation velocity of secondary explosives can be reduced by reducing its density to the level of lead azide. For this purpose, a small amount of nanocomposite or microcomposite containing the combination of RDX and Nano thermite or micro thermite with a density around 0.45 g/cm3 without primary explosive can be used. Nanocomposites or microcomposites, with their high heat of reaction due to the presence of Nano thermite or micro thermite and low density, help the controlled detonation, and the initiation is suitable for Nonels. The sensitivity and toxicity of this nanocomposite or microcomposite is much lower than lead azide. Also, due to the lower activation energy of microcomposites than the safe RDX combination, it has been determined that the microcomposites are even safer than the RDX combination, however, the energy released by the microcomposite is also higher than the pure RDX combination, which this phenomenon helps a lot to the better initiation of the NONELs.

Common surface detonators used in mines have primary explosives. These mineral detonators are used for the initiation of Nonel attached to the detonators in the in-hole because they have less energy and detonation velocity, and are suitable for the activation of Nonel. The reason of less output energy in surface detonators is that the activation of the shock tube besides them is done without destruction of shock tubes on the effect of shrapnel excessive amounts, otherwise, high level energy can damage the shock tube and make their initiation incomplete.

In addition, the production of primary explosives is also extremely hazardous and requires special and expensive equipment and buildings. Also, when assembling the mineral detonators, the probability of accidents is very high.

In general, a primary explosive material is defined as an explosive material that can easily create full detonation under actuated, heat, impact, friction, or electrostatic discharge, even in the absence of any surrounding. Therefore, the main technical problem of the detonators containing primary explosive material such as the lead azide is that the safety of them is low and their production can include hazardous wastes for the environment.

Secondary explosives with high safety and low sensitivity cannot be directly replaced by primary explosive materials in surface detonators, because these materials have high power and this high power leads to the destruction of Nonels instead of initiating them. Therefore, in this invention, the goal is to use Nano composites or Microcomposite with unique features. These Nano composites or Microcomposite contain Nano thermite or micro thermite and a secondary explosive, such as RDX, to provide high temperature and heat to reach the initiation with high certainty Nonels. These Nano composites or Microcomposite have a low density which is due to the appropriate pressure for Nano composites or Microcomposite to reduce the power and detonation velocity to achieve the power and detonation velocity in the bound of lead azide.

Increased safety and reduction of toxic compounds with complete elimination of dangerous compounds such as lead azide from well-known surface detonators is caused by adding Nano composite or Microcomposite.

However, the energy or heat released by the Microcomposite is higher than the pure and safe RDX composition, which helps in better initiation of Nonel.

Solution of problem

A nanocomposite [Chart. 14] or Microcomposite containing secondary explosive, such as RDX and Nano thermite [Chart. 11] or micro thermite can be detonated only if it is subjected to a severe impact wave or severe mechanical impact, hence this nanocomposite [Chart. 14] or Microcomposite is much safer than primary explosive, such as lead azide. In addition to the compounds that can be used for the fabrication of nanocomposite [Chart. 14] or Microcomposite, damage to the environment can be reduced. Thus, if this nanocomposite [Chart. 14] or Microcomposite has an output such as the lead azide, it is an excellent alternative to that compound. It is expected that due to the lack of primary explosive in the surface detonator , the surface detonator produced with these materials has a high resistance against stimuli such as impact and shock waves.

According to the status of literature, sensitivity to shock wave of surface detonators was investigated, so that the produced surface detonators with these nanocomposites [Chart. 14] or Microcomposite were placed at different distances relative to another standard detonator, and after the initiation of the standard detonator, the shock wave produced by it did not initiate the detonators produced by Microcomposite which illustrates their high safety against reached shock wave. However, some of the detonators produced by the nanocomposites [Chart. 14], which were located at intervals of 2.5 cm from the center, were initiated and at longer distances they were not initiated. However, if this test is used for standard detonators containing lead azide, most of them will be initiated easily, which indicates their low safety.

According to the literature regarding impact test, surface detonators produced by Microcomposite were not initiated which indicates their safety against the impact stimulus. However, in a test with a weight height of 11.4 kg equal to 2.3 m, some of the surface detonators produced by nanocomposites [Chart. 14] were initiated. However, the test for surface detonators containing the lead azide showed that all of the surface detonators were initiate in this condition. Therefore, due to the very low sensitivity of Microcomposite and also the nanocomposites compared to the lead azide, easily and without any precautions to be taken, these surface detonators can be manipulated and transported. For this purpose, the use of nanocomposites [Chart. 14] or Microcomposite to reduce and control the final detonation velocity of base charge of the surface detonators which is used for the initiation of Nonels, is more appropriate than lead azide. Therefore, these nanocomposites [Chart. 14] or Microcomposite can be used to construct surface detonators.

For this purpose, it is preferable to use the RDX, but this product is not limited to this secondary explosive and other compounds such as HMX, PETN, CL-20, TNT, etc. can be used. It is also preferable to use Al, but this product is not limited to this metal, and other metals such as Zr, Ti, V, Mo, Fe, Cr, Mg, Ni, Co, and so on, and even their alloys as fuel can be used. It is also preferred to use metallic Nano or micro copper oxide CuO (Figures 1, 2, 3, 4, 5, 6), but this product is not limited to this metallic Nano or micro micro copper oxide, and other metallic Nano or micro metal oxides such as TiO₂, V₂O₅, MoO₃, Cr₂O₃, WO₃, Fe₂O₃, Fe₃O₄, CoO, Co₃O₄, MnO, Mn₂O₃, Mn₃O₄, MnO₂, MgO, NiO, ZnO, etc. and even mixtures of them and also the spinels can be used as oxidizer.

In the nanocomposites [Chart. 14] or Microcomposite, it is preferable to use approximately 90 wt.% of RDX with a particle size of less than 50 µm, but this product is not limited to this weight percentage and about 60 to 95 wt.% of this compound can be used. Also, according to the type of materials used for the preparation of Al+CuO [Chart. 11], the weight percentages of fuel and oxidizer are used, so that the weight percentage can be changed, and for aluminum the weight range of 10-50%, and for copper oxide the range of 50-90 wt.% can be considered. For other Nano thermites, except for Al+CuO, these conditions are also applicable. However, according to literature, for micro thermite it is preferable to choose the percentage of aluminum equal to 20 wt.% and copper oxide 80 wt.%. Also, a very small amount of binder (about 0.3 % to 0.5 %) is used in this nanocomposite [Chart. 14] or Microcomposite. If the surface detonator is used in the coal mines, instead of the Al fuel, other metals that do not have hazardous reaction with gases in these mines should be used.

It is preferable that the density of this nanocomposite [Chart. 14] or Microcomposite as the base charge be about 0.45 g/cm³, but its value can be in the range of 0.35-0.6 g/cm³, so that the nanocomposite [Chart. 14] or Microcomposite produce lower power. If the density of nanocomposite [Chart. 14] or Microcomposite rises, a strong metal jet, as a result of the base charge detonation, leads to destruction of Nonels at the initiation, thus the Nonels will not be initiated well. In these surface detonators the existence of RDX creates the shock wave (albeit with low power), and Nano thermite (Al+CuO) [Chart. 11] or micro thermite that provide high temperature and heat, can lead to safe and accurate initiation of Nonels containing HMX+Al. Thus, the low density and coexistence of Nano thermites [Chart. 11] or micro thermite, first, can reduce the detonation velocity of nanocomposites [Chart. 14] or Microcomposite, and second, the presence of Nano thermites [Chart. 11] or micro thermite produces high temperature and heat that is beneficial for initiation of Nonels. If the density of the nanocomposites [Chart. 14] or the desired Microcomposite can reach about 1.5 g/cm³ by increasing the press pressure, they can be used as the base charge in the in-hole detonators. Therefore, this nanocomposite [Chart. 14] or Microcomposite can be used according to the production conditions in both types of detonators, namely, the surface and in-hole.

Al nanoparticles are highly reactive and may cause burns or even an unwanted and uncontrolled detonation. For this reason, the Al micro particle with a size of 5-15 µm was used. The standard known detonators used in mines generally consist of a hollow and stretched cylindrical metallic shell [Fig. 1 (1)] which is closed at one end. In the production of desired surface detonators in this design the required weight of the nanocomposite [Chart. 14] or Microcomposite as the base charge can be in the range of 100-200 mg, however, in this design, it is preferable that the weight of nanocomposite [Chart. 14] or Microcomposite be about 135 mg, which will be pressed in the closed end of the metallic shell made of aluminum or copper (for coal mines) [Fig. 1 (1)] with low density.

To sum up, first, section 7 is initiated by section 9 and then sections 5 and 4 are initiated, and finally nanocomposite [Chart. 14] or Microcomposite which, eans section 2 is initiated. In section 7 the lead oxide, silicon, and barium sulfate, in section 5 a compound consists of a mixture of 80% of PETN, 10% potassium perchlorate, and 10% potassium picrate with a density of about 1.5 g/cm³, and in section 4 the PETN with density of about 1.1 g/cm³ is used. Also, in the most important part, i.e., section 2 the nanocomposite [Chart. 14] or Microcomposite with a density of about 0.45 g/cm³ is used. In addition to the base charge difference in the presented detonator in this invention with the previous inventions, the number of steps in manufacturing the detonator presented in this invention is also important in mass production, because when the primary charge is loaded in section 1 these materials will not be pressed like previous inventions, instead after that process, section 3 containing sections 4 and 5 that are pressed in it and the bottom part is empty, it is placed in base charge in section 1 and all the previous sets will be pressed under the pressure of about 8.5 MPa. This is important in two aspects: 1. reducing the base charge density and 2. reducing the number of production steps.

Three different tests, namely placing detonators at -40 °C and 70 °C (for 12 hours) and ambient temperature [Table. 1] were designed for nine detonators containing RDX, nine detonators containing nanocomposites [Chart. 14] and Microcomposite with different percentages as the base charge (with constant retention of other variables). For each of the conditions mentioned, three surface detonator samples were constructed. In each test, five shock tubes were placed against the detonator. In this test, five Nonels were placed in a plastic block from one side and on the other side the detonator is placed, and after initiation of the surface detonator the number of initiated Nonels are counted. When pure RDX was used, 100% of the shock tubes were not initiated and in the best case only 66% of them were initiated, which is not an acceptable percentage and the worst case is created in hot temperature in which 40% of Nonels were initiated. When the nanocomposite [Chart. 14] was used with different percentages, all the Nonels were initiated well due to the appropriate energy use as shock and heat. However, when Microcomposite with different percentages were used, all Nonels were well initiated for the specific percentage of micro thermite (Al+CuO). In a Microcomposite in which the aluminum percentage equals to 20 wt.% and copper oxide percentage was 80 wt.%, the initiation was well done due to the appropriate use of energy as shock and heat. However, in other Microcomposite, the initiation is not well done. For more investigation, 100 other detonators containing Microcomposite with specific percentage of micro thermite (Al+CuO) were prepared and tested under different conditions which has acceptable results [Table. 1]. Due to the harder and more expensive production condition of nanocomposites due to the synthesis of CuO nanoparticles, and also the use of ultrasonic process in preparation of nanocomposites for the proper distribution of nanoparticles in nanocomposites, it is better to achieve a suitable weight percentage of Microcomposite in the industrial condition. Also, according to the sensitivity and impact test of surface detonators and also the higher activation energy of Microcomposite than the pure RDX which is calculated by the Kissinger method, it is shown that under the mass production conditions while using Microcomposite, it is best to use nanocomposites and even pure RDX to achieve higher safety. Also, the energy or heat released by the Microcomposite is higher than the pure RDX which helps the better initiation of Nonels. In addition to the initiation of safe Nonels with detonators containing nanocomposites or Microcomposite presented in this invention, they can be used for all other applications of standard detonators containing lead azide and there are no limitations.

The prepared nanocomposite or Microcomposite of about 350-450 mg and density of about 1.5-1.7 g/cm³ due to higher thermal stability and higher safety compared to compounds such as PETN and RDX can be used as the base charge in in-hole detonators. Also, nanocomposite or Microcomposite compared to common compounds such as RDX produces more heat and energy and this more heat and energy is effective is better performance of in-hole detonators.

Advantage effects of invention

The main advantage of the present surface detonator is that it can be produced through a similar method with existing detonators in previous inventions and existing products in fewer steps. According to this, the present surface detonator is similar to those available in previous inventions and manufacturing products in terms of shape, except that the primary charge portion was replaced with prepared nanocomposites or Microcomposite. Therefore, there is no need to change production lines to produce this product. The nanocomposites or Microcomposite used in this invention are safer than primary explosive materials such as lead azide and even PETN. It has been shown that the activation energy of Microcomposite is higher than that of pure RDX which indicates higher safety. Therefore, in the production and application stages of these nanocomposites or Microcomposite, and also while using the surface detonators containing this material in mines, the occurrence of irreversible incidents can be reduced severely. It is found that the heat released from the Microcomposite is higher than the pure RDX, which improves the initiation process of Nonels. Also, these substances do not produce toxic gases such as ammonium perchlorate and lead azide, so the health of the workers in the mines is maintained and the harmful pollutions in the environment will be drastically reduced. Due to the presence of Nano thermite or micro thermite, high temperature and heat have been produced during the detonation of nanocomposites or Microcomposite which helps the initiation of Nonels with high reliability. The surface detonators presented in this invention can be used for all standard detonators applications containing lead azide and there are no limitations. The prepared Microcomposite can be used as the base charge in the conventional in-hole detonators. By removing aluminum shell and using a shell made of copper and also by removing aluminum from nanocomposites or Microcomposite and using another fuel, the present detonator can be used in the coal mines as well. Another advantage of this invention is that these nanocomposites or Microcomposite can be used in flat head structures (similar to the in-hole detonator shell) or convex, like the standard surface detonators so that they have proper performance in both

: shows the map of the flat-head surface detonator

: 1. the metal cylinder of the closed end aluminum material in shape of flat-head 2. Nanocomposite containing Nano thermite and pure RDX or Microcomposite including micro thermite and RDX with weight of 135 mg with density of about 0.45 g/cm³ is placed in a metallic cylinder made of aluminum in section 2 of a metal cylinder made of steel with an external diameter of about 6.3 mm and inner diameter of 4.0 mm, length of 30.0 mm 4. containing PETN with a density of about 1.1 g/cm³. 5. Containing 80% of PETN, 10% potassium perchlorate, and 10% potassium picrate with density of about 1.5 g/cm³. 6. a metal cylinder made of zinc with an internal and external diameter similar to Figure 10 (3) with a length of 10.0 mm). 7. is a delay composition of lead oxide, silicon, and barium sulphate. 8. is Nonel (non-electrical) or wire (electrical). 9. is isolated made of plastic.

Examples

The following steps were made to produce the first samples of surface detonators used in the mines:

Preparation of Nanocomposite

First, copper oxide nanoparticles (CuO) were synthesized by the sol-gel method.
Using ultrasonic process for 3 hours in hexane environment, Nano thermite (Al+CuO) was prepared as a sample with an aluminum percentage of 20 wt.% and copper oxide percentage of 80 wt.%.
Using ultrasonic process for 3 hours and then magnetic stirring for 3 hours in hexane environment, nanocomposite (Al+CuO+RDX) was prepared by Nano thermite percentage of 10 wt.% and RDX percentage equal to 90 wt.%.
Nanocomposite was dried at 50-60 °C for 24 h.
The nanocomposite was mixed manually with a binder, i.e. nitrocellulose, in amount of 0.4 wt.%.
Compound of step 5 was dried for 6 h.
Finally, for homogenizing, the compound of step 6 was passed through a proper sieve.

Preparation of Microcomposite

Using the mixing process with a simple mixer for 3 h in hexane environment, the Microcomposite (Al+CuO+RDX) with micro thermite percentage equal to 10 wt.% (as a sample with aluminum percentage of 20 wt.% and copper oxide percentage equal to 80 wt.%) and RDX percentage equal to 90 wt.% was prepared.
Microcomposite was dried at temperature of about 50-60 °C for 24 h.
The Microcomposite was mixed manually with a binder, i.e. nitrocellulose, in amount of 0.4 wt.%.
Compound of step 3 was dried for 6 h.
Finally, for homogenizing, the compound of step 4 was passed through a proper sieve.

Manufacturing Surface Detonators

The loading of materials of ( (5)) containing 80% PETN compound, 10% potassium perchlorate, and 10% potassium picrate inside section 3 made of steel ( (3)).
Pressing the materials of ( (5)) containing 80% PETN compound, 10% potassium perchlorate, and 10 % potassium picrate with a density of about 1.5 g/cm³, inside section 3 made of steel ( (3)).
The loading of materials of ( (4)) containing PETN inside section 3 made of steel ( (3)).
Pressing the materials of ( (4)) containing PETN with a density of about 1.1 g/cm³, inside section 3 made of steel ( (3)).
The loading of materials of ( (7)) is a delay composition of lead azide, silicon, and barium sulphate inside section 6 made of zinc ( (6)).
Pressing the materials of ( (7)) is a delay composition of lead azide, silicon, and barium sulphate inside section 6 made of zinc ( (6)).
The loading of nanocomposite or Microcomposite of ( (2)) in section 1 made of aluminum ( (1)).
Inserting section 3 made of steel ( (3)) containing sections 5 and 4 in section 1 made of the aluminum ( (1)).
Pressing section 3 made of steel ( (3)) containing section 5 and in section 1 made of aluminum ( (1)).
Inserting section 6 made of zinc ( (6)) containing section 7 ( (7)) in section 1 made of aluminum ( (1)).
Pressing section 6 made of zinc ( (6)) containing section 7 ( (7)) in section 1 made of aluminum ( (1)).
Inserting an isolation made of rubber of section 8 ( (8)) in section 1 made of aluminum ( (1)).
Placing Nonel of section 9 ( (9)) in isolation of section 8 made of rubber ( (8)).
Crimping above section 1 made of aluminum ( (1)).

[Chart. 1]

[Chart. 1] illustrates XRD analysis from copper oxide nanoparticles. By analyzing this spectrum, it is clear that it is according to JCPDS card number 00-048-1548, so the synthesis of these nanoparticles is well done and the structure of CuO nanoparticles are well formed and the impurity is not included in the copper oxide Nano particles.

[Chart. 2] FESEM analysis of copper oxide nanoparticles show two different magnifications.

[Chart. 3] the EDX analysis.

According to the images, it is clear that the particles containing Nano metrical size and morphology are almost spherical. EDX analysis was used to study the amount and confirmation of various elements on the surface of synthesized copper oxide nanoparticles. As indicated, the peak level of Cu and O elements compared to other elements is higher and higher level of peak indicates high percentage of these elements in the synthesized sample.

[Chart. 4] illustrates AFM analysis of copper oxide nanoparticles.

In this chart two and three dimensional images of copper oxide nanoparticles were shown respectively. To investigate the roughness and topography of the surface of synthesized copper oxide nanoparticles, these nanoparticles were investigated by AFM analysis. As observed, the roughness of the surface (RMS) and maximum height (H_max) for copper oxide nanoparticles were 3.269 nm and 14.39 nm, respectively.

[Chart. 5] illustrates HRTEM analysis of copper oxide nanoparticles in two different magnifications.

[Chart. 6] shows the percentage of nanoparticles sphericity.

[Chart. 7] shows histogram graph

This analysis was carried out to accurately investigate the size and morphology of the nanoparticles. In [chart. 5] the copper oxide nanoparticles were shown with spherical morphology and the size less than 100 nm. As shown in [chart. 7] the size of about 70% of these nanoparticles is less than 10 nm and generally the size of these particles is less than 100 nm. Also, according to [chart. 6], the morphology of about 40% of these nanoparticles is spherical and since the Circ. parameter of other nanoparticles is close to one, they can be considered spherical.

[Chart. 8] imaging of two different regions is shown in two magnifications

[Chart. 9] the electron diffraction pattern of the selected region was shown in (SAED) and (FFT) respectively.

In [Chart. 8] the generated rings illustrate the polycrystalline feature of the synthesized sample. Ring diffraction patterns exist when a large number of crystals are aligned with the different orientation of the reflected electron beam. [Chart. 9] also contains fewer crystals because the electron diffraction analysis is done only for a very small region, and therefore, complete and continuous rings are not formed, and only the clear points from the two crystal planes are represented. The comparison of results of XRD and HRTEM analyses revealed that the distance between crystal plates and formed crystal planes has high conformity.

[Chart. 10] illustrates the BET analysis copper oxide nanoparticles. The BET analysis was used to determine the specific surface area (S_BET). This analysis is based on the absorption and desorption of nitrogen gas volume. The results of this analysis were shown as absorption-desorption isotherm and the specific surface area of copper oxide nanoparticles equal to 5.98 m²/g is reached. According to this figure, the absorption and desorption obtained in samples are according to the IUPAC classification in Type III, which shows the weak interaction between the absorbent and absorption, as well as that of a nonporous solid. These results are also consistent with the images of FESEM and HRTEM analyses, as in the images of these analyses no porous in copper oxide nanoparticles is observed.

[Chart. 11] shows the FESEM analysis.

[Chart. 12] shows mapping analysis

[Chart. 13] shows the EDX analysis of Nano thermites.

In [Chart. 11] the morphologies of two Al and CuO compounds are presented. It is known that CuO nanoparticles cover Al micro particles. [Chart. 12] shows the distribution of elements of O, Al, and Cu as well as the total elements in an image (Com). It is clear that the prepared Nano thermite has a good distribution of elements. In [Chart. 13] EDX analysis is shown to study the amount and confirm the existence of the elements present in the Nano thermite. As indicated, the peak level of Al, Cu, and O elements compared to other elements is greater and the higher peak level indicates the high percentage of these elements in the synthesized sample.

[Chart. 14] shows the FESEM analysis

[Chart. 15] shows mapping analysis.

[Chart. 16] shows the EDX analysis of Nano composites.

In [Chart. 14] morphologies of three compounds including RDX, Al, and CuO are shown. [Chart. 15] shows the distribution pattern of elements of O, Al, Cu, and N, as well as all the elements in an image (Com). It is clear that the prepared nanocomposites have a suitable distribution of elements. In [Chart. 16], EDX analysis is shown to study the amount and confirm the existence of the elements present in the Nano composites. As indicated, the peak level of Al, Cu, O, and N elements compared to other elements is greater and the higher peak level indicates the high percentage of these elements in the synthesized sample.

[Chart. 17] The TG analysis from the pure RDX at the heating rate of 5, 10, 15, and 20 °C/min and under argon gas environment. It is known that at all heating rates, the sample weight is reduced and completely degraded in one step.

[Chart. 18] The DSC analysis of the RDX at the heating rate of 5, 10, 15, and 20 °C/min and under argon gas environment. In all heating rates, the decomposition of pure RDX at different peak temperatures is shown. According to the heating rate of 5, 10, 15, and 20 °C/min, the temperature peaks of the decomposition of this compound were 236.02, 245.67, 252.39, and 256.7 °C, respectively. Also, the heat released from the RDX at the standard heating rate of 10 °C/min equals 1754/89 J/g.

[Chart. 19] Linear fitting plot of ln(β/T²) based on 1/T for the pure RDX. According to the Kissinger method, the activation energy of the pure RDX is calculated by the graph slope to be 140.82 kJ/mol.

[Chart. 20] TG analysis from Microcomposite at the heating rate of 5, 10, 15, and 20 °C/min and under argon gas environment. It is known that at all heating rates, the sample weight is reduced and completely degraded in one step. Therefore, the temperature range of weight reduction of this sample is increased compared to the pure RDX.

[Chart. 21] The DSC analysis of Microcomposite at the heating rate of 5, 10, 15, and 20 °C/min and under an argon gas environment. In all heating rates, the decomposition of pure RDX at different peak temperatures is shown. According to the heating rate of 5, 10, 15, and 20 °C/min, the peak temperatures of decomposition of this compound were 241.01, 250.38, 254.19, and 258.54°C, respectively. By comparing these results with data of section (b) for the pure RDX, it is clear that the decomposition temperature for the Microcomposite is somewhat increased. Also, the heat released from the Microcomposite at the standard heating rate of 10 °C/min equals 2116.58 J/g. As a result, the amount of heat released from Microcomposite is higher than that of pure RDX.

[Chart. 22] linear fitting plot ln(β/T²) based on 1/T for Microcomposite. The activation energy of Microcomposite is achieved to be 173.58 kJ/mol, which is clearly higher than that of pure RDX.

Success rate	The number of activated tubes	The total number of tested tubes	The total number of tested capsules	temperature (°C)	The main flux
66%	10	15	3	Environment	RDX
53%	8	15	3	40-
40%	6	15	3	70
100%	45	45	3	Environment	CuO/Al=9	Nano composite
100%	45	45	3	40-
100%	45	45	3	70
100%	45	45	3	Environment	CuO/Al=4	Nano composite
100%	45	45	3	40-
100%	45	45	3	70
100%	45	45	3	Environment	CuO/Al=1	Nano composite
100%	45	45	3	40-
100%	45	45	3	70
84%	38	45	3	Environment	CuO/Al=9	Microcomposite
75%	34	45	3	40-
82%	37	45	3	70
100%	45	45	3	Environment	CuO/Al=4	Microcomposite
100%	45	45	3	40-
100%	45	45	3	70
91%	41	45	3	Environment	CuO/Al=1	Microcomposite
80%	36	45	3	40-
86%	39	45	3	70
100%	500	500	100	Under different conditions	CuO/Al=1	Microcomposite

[Table. 1] The results of the performance tests of surface detonators under different conditions for composites containing 90 wt.% pure RDX for all samples.

This invention is used in mines.

Claims

A detonator without primary explosives consisting of one open side and one closed side metallic shell, includes the following components:
A closed side and an open side made of aluminum,

Nanocomposite or micro-composite as the main charge,

A steel cylinder containing a PETN compound with a density of about 1.1 g/cm3 and a mixture containing 80% of the PETN compound, 10% potassium perchlorate, and 10% potassium picrate with a density of about 1.5 g/cm3,

A cylinder made of zinc metal filled with delay element,

An isolated and

A shock tube.
According to claim 1, nanocomposite or micro-composite prepared with controlled energy (shock wave and heat) and the density is about 0.45 g/cm3, although its density can be in the range of 0.35-0.6 g/cm3. This nanocomposite or micro-composite consists of RDX compounds with a size less than 50 µm (or HMX, PETN, CL-20, TNT, etc.) compounds, Al (or Zr, Ti, V, Mo, Mn, Fe, Cr, Mg, Ni, Co, etc. and even their alloys) as fuel with a size in the range of 5-15 µm and CuO nanoparticles or microparticles, respectively size less than 100 nm and 50 µm (or TiO2, V2O5, MoO3, Cr2O3, WO3, Fe2O3, Fe3O4, CoO, Co3O4, MnO, Mn2O3, Mn3O4, MnO2, MgO, NiO, ZnO, etc. and even a mixture of them as well as spinels) as an oxidizer, instead of primary explosives such as lead azide, to begin with, shock tubes have safer conditions in the process of manufacturing, producing and using the final product, i.e. surface detonator. It can be used in mines compared to the lead azide compound and even the pure RDX compound due to the increase in the micro-composite activation energy and also the reduction of environmental pollutants due to the lack of production and use of the lead azide compound.
According to claim number 2, the weight percentages of Al, CuO, and RDX compounds can be in the range of 10-50, 50-90, and 60-95 respectively for nanocomposite, but for micro-composite, the weight percentage of Al and CuO compounds in micro thermite (Al+CuO) should be 20 and 80, respectively, and also the weight percentage of RDX compound in nanocomposite or RDX+Al+CuO micro-composite should be 90 and the weight percentage of Nano-thermite or micro thermite (Al+CuO) in the desired nanocomposite is chosen equal to 10 so that it has been determined that the heat released from the micro-composite is higher than the pure RDX composition, which helps the better initiation of the nanocomposites.
According to claim 1, the absence of nanocomposite or micro-composite pressing after loading in the metallic shell and the nanocomposite or micro-composite pressing and the steel cylinder together in the metallic shell in addition to the reduction on the nanocomposite or micro-composite, leads to a reduction in the production process due to the removal of the press will be direct nanocomposite or micro composites.
According to claim 1, according to the proper performance tests performed with a straight cylinder instead of a convex head, a straight cylinder can be used instead of a convex head, which makes the production process easier.
(Independent claim) Due to greater thermal stability and as a result, higher safety compared to compounds such as PETN and RDX, as well as creating higher energy of micro composite than these compounds, which is ultimately effective in the better performance of the desired product we can use from micro composite composed of about 350-450 mg and a density of about 1.5-1.7 g/cm3 can be used in the common intracavity detonator.