Prilled explosive composition

Abstract

An explosive composition made from an oxidising liquid and a polymeric superabsorbent material that acts as a fuel and absorbs the oxidising liquid, forming spherical particles and that works as an explosive. The explosive composition can be prepared in rotary or stationary devices. The explosive composition can be used in mines (open pit and underground), quarries, and civil construction projects like tunnelling and the likes).

Description

Prilled explosive composition

[0001] The present disclosure relates generally to the field of explosives. In particular, the present disclosure relates to an explosive composition made from hydrogen peroxide solution and a polymeric shaped absorbent material. The present disclosure also relates to methods for preparing an explosive composition, and the use of said composition in mines (open pit and underground), quarries, and civil construction projects tunnelling and the likes.Background

[0002] The mining industry uses ammonium nitrate (AN) to make explosives. AN is an oxidiser material, spherical-like particles (also known as “prills”), which combined with fuel (diesel, fuel oil, oils, etc.) in a mine (open pit or underground), quarries, tunnelling or other types of civil construction projects, to make prilled ANFO. This material can act as an explosive as it can detonate (G.B. Clarke; “Basic properties of ammonium nitrate fuel oil explosives (ANFO)”; Colorado School of mines press, 1981) when initiated by explosives like pentolite (a mixture of trinitrotoluene / pentaerythritol tetranitrate, TNT / PETN). It is worth noting that, to achieve a detonation, the spherical particles of AN prills must be porous to absorb the fuel (at least 5.5% of fuel), otherwise, the final product will not properly detonate. The porosity of the AN prills is obtained at the manufacturing plant.

[0003] Other types of explosives that are used by the mining industry are emulsion and watergel explosives, usually called blasting agents. These products are mixtures of AN solution (AN solubilised in water), other solubilised oxidiser materials, fuel and emulsifiers (for emulsions, see for example US Patent 4,111,727) or thickeners (for watergels, see for example US Patent 3,153,603). Note that the AN in this case is dissolved in water before making the blasting agent. Once made, these materials need the incorporation of voids, or they cannot detonate. This process of void incorporation into energetic materials is called sensitisation. These explosives cn also be blended with AN prills to vary the detonation properties of the final explosive. Emulsions and watergels are fluids with a high viscosity and pumps are required to handle them.

[0004] Recent years have seen the commercialisation of new explosives that use hydrogen peroxide (HP) as the oxidising material instead of AN. (see for example https: / www.hypexbio.com / ). These HP-based products resemble emulsions or watergels, much like the previously described AN-based explosives, and they require a sensitisation process to achieve detonation. These HP-based products are also fluids and required pumps for their handling.

[0005] In the specific case of AN-based emulsions and / or watergels, to sensitise them, voids are created (gas bubbles) by a chemical reaction taking place in the emulsion / watergel product. These gas bubbles can be nitrogen bubbles (see, for example, US Patent 3,390,032; US Patent 3,886,010), carbon dioxide bubbles (see, for example, US Patent 3,288,658) or air (see, for example, US Patent 3,642,547). For HP-based emulsions or watergels, chemical reactions can be used to reaction sensitise the products (see, for example, Cent. Eur. J. Energ. Mater. 2017, 14(4): 759-774)

[0006] These voids can also be solid material with entrapped gas, like solid glass micro balloons (Hattori, K., Y. Fukatsu, and H. Sakai. "Effect of the size of glass microballoons on the detonation velocity of emulsion explosives." Ind Explos Soc Japan 43 (1982): 295-309.) or plastic micro balloons (Lee, Jaimin, and Per‐Anders Persson. "Detonation behavior of emulsion explosives." Propellants, Explosives, Pyrotechnics 15, no. 5 (1990): 208-216.) or expanded polystyrene (CA patent 2005723). For HP-based emulsions or watergels, solid material voids can also be used sensitise the products (see for example Cent. Eur. J. Energ. Mater. 2017, 14(4): 759-774).

[0007] The use of chemicals to create gas bubbles in the blasting agent is a complicated process and requires highly skilled operators. Solid glass micro balloons or expanded polystyrene can be used instead of gas bubbles, as they are less dependent on the operator, but the incorporation of these material into emulsions / watergels in field operations increases the risk of unwanted event like a detonation, as the product is being sensitised and handled by pumps / augers that produce events like friction, impact, etc. that could ignite and detonate these products.

[0008] Building an AN prill manufacturing plant requires a large output (more than 100,000 tonnes / year) for the plant to be commercially viable, and therefore a large investment. This is a clear disadvantage for small companies that would like to manufacture their own AN prill.

[0009] An additional disadvantage is that AN needs to be transported from the manufacturing plant to the site of use, which sometimes is anywhere between 100 to 2,000 km. This transport takes time, which in combination with humidity, like in tropical countries, makes product solidify and it does not any longer flow. Special methods and personnel are required to break the solid material to use it at the destination, to make ANFO or to prepare emulsions / watergels. The breaking solid material activities are time-consuming and potentially hazardous (as AN is a material that can be initiated by impact and there is a potential, although negligible, of an explosion).

[0010] An additional disadvantage is that emulsions and watergels typically require a central manufacturing location where experienced technical personnel can safely make the product, with the required quality characteristics for use at the mine / construction sites. Despite being significantly less expensive than an AN prill manufacturing plant, these emulsion / watergels plants necessitate a significant capital investment, posing a challenge for small explosive users seeking to establish such facilities. Besides the cost concerns, the manufacture of emulsion and watergel explosives must adhere to strict regulations, including technical safety and licencing. Next, the transportation of emulsions and watergels on public roads necessitates compliance with regulatory requirements, ensuring safety, and meeting security requirements. All of these add significant costs to the end user.

[0011] An additional disadvantage of AN-based products, as raw material (AN prills) or blasting agents (emulsions) is that accidents have taken place in the world in public roads).

[0012] An additional disadvantage of AN-based explosives, like emulsions or watergels, is that they require special equipment for their manufacture. This equipment called mobile manufacture units (MMU) or mobile processing units (MPU) or mobile sensitising units (MSU) or mobile explosive manufacturing units (MEMU) are “manufacturing plants on wheels”. They have sensors, pumps, valves, tanks for at least 5-6 chemicals, which makes the emulsion / watergels’ sensitisation process somehow complicated.

[0013] There remains a need to provide an alternative solution to the manufacture of commercial explosives than the described AN-based products (ANFO, emulsions, and watergels) or HP-based products (emulsions and watergels). In particular, there remains the need to provide an alternative approach that is simple, cost-effective, and minimises risk and logistical hurdles in manufacturing, building emulsion plants, regulatory matters (licences), transport, and onsite use.Summary

[0014] The present invention relates to an explosive composition comprising:

[0015] an oxidising liquid and

[0016] a polymeric spherical-shaped absorbing material (PSAM) that acts as fuel, absorbs the oxidising liquid and provides the shape to the final explosive product.

[0017] Optionally a water-soluble fuel that can replace part of the polymeric shaped material absorbing material.

[0018] In preferred embodiments, the explosive compositions of the present invention are composed of a multitude of solid spheres that are formed upon the contact between the oxidising liquid and the PSAM.

[0019] In another aspect of the present disclosure, there is provided a method of preparing the explosive composition as described herein, the method comprising:

[0020] Pumping the oxidising liquid into a receptacle

[0021] Adding the PSAM to the oxidising liquid,

[0022] Allow the PSAM to absorb the oxidising liquid and form the spheres

[0023] In another aspect of the present disclosure, there is provided a use of the explosive composition as described herein as an explosive for use in mines (open pit and underground), quarries, tunnelling and civil construction projects.

[0024] Embodiments of the explosive composition described herein provide the advantage that the raw materials (oxidising liquid and PSAM) can be provided to a blasting site while avoiding the transport of energetic material like AN, emulsions or watergels on public roads, lowering any risk of an accident and potential explosion of the material, which can injure people, destroy public infrastructure, and damage the environment.

[0025] Embodiments of the explosive composition described herein overcome the disadvantages of AN prill, like degradation by humidity followed by hardening of the material.

[0026] Embodiments of the explosive composition described herein provide the advantage that large capital investments to build AN prill plants or to build emulsion / watergel manufacturing plants are not required.

[0027] Embodiments of the method of preparing the explosive composition as described herein provide the advantage that incorporation of voids to sensitise the explosive (a well know technique in the explosives industry) is not required.

[0028] Embodiments of the method of preparing the explosive composition as described herein provide the advantage that expensive explosives loading trucks (MMU, MPU, MSU or MEMU) are not required.

[0029] Embodiments of the method of preparing the explosive composition as described herein provide the advantage of simplifying the manufacture and loading of explosives in mines (open pit and underground), quarries, tunnelling and civil construction projects.

[0030] Whilst it will be appreciated that a variety of embodiments disclosed herein may be utilised, described herein are a number of examples with reference to the following drawings:

[0031] : Pictures of the spherically shaped explosive composition.Detailed DescriptionGeneral terms

[0032] The following is a detailed description of the disclosure provided to aid those skilled in the art in practicing the present disclosure. Those of ordinary skill in the art may make modifications and variations in the embodiments described herein without departing from the spirit or scope of the present disclosure.

[0033] In the following description, reference is made to the accompanying drawings which form a part hereof. It is understood that other embodiments may be used, and structural changes may be made without departing from the scope of the present disclosure.

[0034] With regards to the definitions provided herein, unless stated otherwise, or implicit from context, the defined terms and phrases include the provided meanings. Unless explicitly stated otherwise, or apparent from context, the terms and phrases below do not exclude the meaning that the term or phrase has acquired by a person skilled in the relevant art. The definitions are provided to aid in describing particular embodiments, and are not intended to limit the claimed invention, because the scope of the invention is limited only by the claims. Furthermore, unless otherwise required by context, singular terms shall include pluralities, and plural terms shall include the singular.

[0035] All publications discussed and / or referenced herein are incorporated herein in their entirety.

[0036] Any discussion of documents, acts, materials, devices, articles or the like which has been included in the present specification is solely for the purpose of providing a context for the present disclosure. It is not to be taken as an admission that any or all of these matters form part of the prior art base or were common general knowledge in the field relevant to the present disclosure as it existed before the priority date of each claim of this application.

[0037] Throughout this disclosure, unless specifically stated otherwise or the context requires otherwise, reference to a single step, composition of matter, group of steps or group of compositions of matter shall be taken to encompass one and a plurality (i.e., one or more) of those steps, compositions of matter, groups of steps or groups of compositions of matter. Thus, as used herein, the singular forms “a”, “an” and “the” include plural aspects unless the context clearly dictates otherwise. For example, reference to “a” includes a single as well as two or more; reference to “an” includes a single as well as two or more; reference to “the” includes a single as well as two or more and so forth.

[0038] Those skilled in the art will appreciate that the disclosure herein is susceptible to variations and modifications other than those specifically described. It is to be understood that the disclosure includes all such variations and modifications. The disclosure also includes all of the examples, steps, features, methods, compositions, processes, referred to or indicated in this specification, individually or collectively, and any and all combinations or any two or more of said steps or features.

[0039] The term “and / or”, e.g., “X and / or Y” shall be understood to mean either “X and Y” or “X or Y” and shall be taken to provide explicit support for both meanings or for either meaning.

[0040] As used herein, the phrase “at least one of”, when used with a list of items, means different combinations of one or more of the listed items may be used and only one of the items in the list may be needed. The item may be a particular object, thing, or category. In other words, “at least one of” means any combination of items or number of items may be used from the list, but not all of the items in the list may be required. In some cases, “at least one of item A, item B, and item C” may mean, for example and without limitation, two of item A, one of item B, and ten of item C; four of item B and seven of item C; or some other suitable combination.

[0041] As used herein, the term “about”, unless stated to the contrary, typically refers to + / - 10%, for example + / - 5%, of the designated value.

[0042] It is to be appreciated that certain features that are, for clarity, described herein in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features that are, for brevity, described in the context of a single embodiment, may also be provided separately or in any sub-combination.

[0043] Throughout the present specification, various aspects and components of the invention can be presented in a range format. The range format is included for convenience and should not be interpreted as an inflexible limitation on the scope of the invention. Accordingly, the description of a range should be considered to have specifically disclosed all the possible sub-ranges as well as individual numerical values within that range, unless specifically indicated. For example, description of a range such as from 1 to 5 should be considered to have specifically disclosed sub-ranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 5, from 3 to 5 etc., as well as individual and partial numbers within the recited range, for example, 1, 1.5, 2, 2.2, 3, 4, 4.6, and 5, unless where integers are required or implicit from context. This applies regardless of the breadth of the disclosed range. Where specific values are required, these will be indicated in the specification.

[0044] Throughout this specification the word "comprise", or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated element, integer or step, or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.

[0045] Herein “weight %” may be abbreviated to “wt% or % w / w”.Oxidising liquid

[0046] The present disclosure relates to an explosive composition that uses an oxidising liquid in the formulation.

[0047] In embodiments, the oxidising liquid is a solution made of hydrogen peroxide / water, supplied by Solvay, with concentration from 30% to 80% by weight.

[0048] In embodiments, the density of the HP solution 30-80% by weight has a density between 1.10 g / ml and 1.35 g / ml.Polymeric shaped absorbent material (PSAM)

[0049] The present disclosure relates to an explosives composition that uses a PSAM in the formulation. PSAM materials are well known in agriculture (see for example Chang, Liangyu, Liju Xu, Yaohu Liu, and Dong Qiu. "Superabsorbent polymers used for agricultural water retention." Polymer Testing 94 (2021): 107021).

[0050] In embodiments, PSAM is selected from the group of polyacrylates or polyacrylamides. The material was supplied by either waterbeadsaustralia.com.au or by Shenyang Runbang Environmental Protection Technology con. Ltd.

[0051] In embodiments, PSAM must be spherically shaped, with a diameter between 0.05 and 0.5 mm before the absorption process.

[0052] In the embodiments, PSAM absorbs liquids, where the liquids are oxidising liquids and the final diameter of the spheres being between 0.1 to 10mm.

[0053] The PSAM material also works as a fuel for the oxidising liquid, forming the required oxidiser / fuel composition balance required by an explosive.

[0054] In embodiments, the absorbent material content in the composition (% w / w based on the total weight of the composition) is between about 0.1 and to about 25.

[0055] In embodiments, the small, spherically shaped material, formed by the absorption of the oxidising liquid by the PSAM act as a sensitiser for the explosives.Water soluble fuel

[0056] In embodiments, an optionally water-soluble chemical could be used to replace parts of the PSAM, to:

[0057] reduce the amount of PSAM in the formulation or

[0058] to change the detonation properties of the explosive.

[0059] water-soluble fuel is selected from the group consisting of alcohols, hexamine, urea, sugar, and combinations thereof.

[0060] In embodiments, the alcohol may be a C2 – C12 alcohol. That is, the alcohol compound has between 2 to 12 carbon atoms in total, whether they be in a single carbon chain or across multiple carbon chains combined. Alcohol within these size ranges tend to be liquids at room temperature and / or have the desired solubility profile. C2 – C12, or C2 – C9 or C2 – C6 alcohol which are generally considered soluble in water are particularly preferred (ethanol, glycerol, tri ethanol amine).

[0061] In embodiments, at room temperature, the alcohol is a water-soluble liquid. By soluble in water, it is intended that the solubility of the relevant alcohol in water would be at least about 1g / L, preferably at least about 100g / L or fully miscible with water.Method of making an explosive composition

[0062] In another aspect of the present disclosure, there is provided a method of preparing the explosive composition as described herein, the method comprising:

[0063] contacting the HP solution with PSAM material as described herein to form the explosive composition.

[0064] In embodiments, the contact occurs in a receptacle, wherein the receptacle can rotate, or it is stationary.Use of the explosive composition

[0065] In another aspect of the present disclosure, there is provided the use of the explosive composition described herein as an explosive.

[0066] In embodiments, the contacting of the HP solution and the PSAM material in a receptacle occurs in a mine, quarry or civil construction project.ExamplesExplosive composition preparation

[0067] Samples to measure the detonation of the product were prepared as follows: 6,4000grams of HP solution 70% by weight was placed in a 20-litre plastic container. The HP solution was stirred, and 1,600 grams PSAM material was added. The mixture’s stirring stopped when the PSAM material displayed that it had absorbed most of the HP solution and the material had become small spherical particles. The container was further rotated for the PSAM to continue absorbing the HP solution. The density of the explosive composition was measured, and it was 0.92 g / ml. The total weight of the explosive composition was around 8 kg. More explosive composition samples were prepared. In these explosive compositions, the concentration of the HP solution was varied. Also, tests were conducted where part of the HP solution was replaced with glycerine (a water-soluble fuel), and that amount of fuel also allowed for the reduction of the amount of PSAM. A summary of the formulas prepared (by percentages) is displayed in Table 1. The final explosive composition would have an oxygen balance between -15 and +15.

[0068] Table 1.Formulas tested.Sample#1#2#3#4#5HP solution 70% w / w80.079.0HP solution 60% w / w81.6HP solution 50% w / w85.084.5PSAM20.015.02.02.02.0Glycerine19.016.413.5Velocity of detonation test

[0069] Then the explosive compositions were transferred into a PVC pipe, with a PVC cap in one end to seal it. This pipe was taken to the testing area where it was hung to a frame. A coaxial cable was attached to the pipe. An instrument manufactured by ShotTrack Pty Ltd Australia was used to measure the velocity of detonation of the samples. A coaxial cable was attached to the Shottrack instrument, and the other end was attached along the PVC pipes to capture the data. Table 2 displays the VOD of the samples.

[0070] Table 2.VOD of the samples.Sample#1#2#3#4#5VOD [m / s]2885Detonated36852897Failed

[0071] The conclusion of the detonation tests was that spherically shaped explosive compositions comprising the HP solution (at different concentrations and with or without glycerine) and the PSAM material of the present disclosure can detonate.

[0072] It will be appreciated by persons skilled in the art that numerous variations and / or modifications may be made to the above-described embodiments without departing from the broad general scope of the present disclosure. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive.

Claims

An explosive composition comprising:An oxidising liquid; andAt least one PSAM materialThe explosive composition of claim 1, wherein the oxidising liquid is a solution of hydrogen peroxide.The explosive composition of claim or claim 2, wherein the concentration of the hydrogen peroxide in the hydrogen peroxide / water solution is between 30% w / w and 80% w / w.The explosive composition of claim 1, wherein the PSAM material is an absorbent polyacrylamide polymer or an absorbent polyacrylate polymer, with a spherical shape and a diameter size between 0.05mm and 0.5 mm.The explosive composition of any one of the preceding claims, wherein the PSAM material absorbs up 99% the hydrogen peroxide solution upon contacting, forming a spherically shaped explosive composition.The explosive composition of any one of the preceding claims, wherein the HP solution content in the explosive composition is (% w / w based on the total weight of the composition) between about 60 to about 90.0%.The explosive composition of any one of the preceding claims, wherein the PSAM material content in the composition is (% w / w based on the total weight of the composition) between about 0.1 and about 40.0%.The explosive composition of claim 1, claim 2, and claim 3, wherein a water-soluble fuel is present in the hydrogen peroxide solution.The explosive composition of any one of the preceding claims, wherein the water-soluble fuel present in the hydrogen peroxide solution is glycerine, ethanol, propanol, isopropanol, sugar, urea, hexamine, or combinations thereof.The explosive composition of any one of the preceding claims, wherein the water-soluble fuel content in the composition is (% w / w based on the total weight of the composition) between about 0.1 and about 39.9.The explosive composition of claims 8, claim 9 and claim 10, wherein the PSAM material content in the composition is (% w / w based on the total weight of the composition) is adjusted according to the water-soluble fuel presence and is between about 0.1 and about 39.9%.An explosive composition of any one of the preceding claims, wherein the final density of the spherical-shape explosive composition is between 0.60 to 1.10 g / ml.A method to prepare the explosive composition as described herein, the method comprising:A receptacleAn oxidising liquid of claims 1, claim 2, claim 3, claim 6, claim 8, claim 9 and claims 10.A PSAM material of claims 2, claim 4, claim 5, claim 7 and claim 11.A method to prepare the explosive composition of claim 13, wherein the receptacle is rotating or stationary.A method to prepare the explosive composition of claim 13 and claim 14, wherein the HP solution (with or without a water-soluble fuel) is added to the receptacle.A method to prepare the explosive composition of Claim 13, Claim 14 and Claim 15, wherein the PSAM material is added to the receptacle.The explosive composition of any one of claims 13 to 16, wherein the PSAM material content in the explosive composition is (% w / w based on the total weight of the explosive composition) is between about 0.1 and about 39.9.The explosive composition of any one of claims 13 to 17, wherein the PSAM material forms small spheres / beads upon absorbing the HP solution (with or without a water-soluble fuel).A method to prepare the explosive composition according to any of the claims 13 to 18, wherein the density of the explosive composition is between 0.6 g / ml to 1.10 g / ml.A method to prepare the explosive composition according to claims 13 to 19, wherein the explosive composition prepared in the rotating / stationary receptacle is poured into a blasthole in an open pit or underground mine, or a quarry, or in a civil construction project like tunnelling, bridges, and buildings.A method to prepare the explosive composition according to claims 13 to 23, wherein the stationary receptacle is a blasthole in an open pit or underground mine, or a quarry or in civil construction project like tunnelling, bridges, and buildingsA use of the explosive composition of any one of claims 13 to 24 as an explosive.

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