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CA-3088893-A1 - MECHANICALLY-GASSED EMULSION EXPLOSIVES AND METHODS RELATED THERETO

CA3088893A1CA 3088893 A1CA3088893 A1CA 3088893A1CA-3088893-A1

Abstract

Emulsion explosives with gas bubbles that are resistant to in-borehole migration or coalescence are disclosed herein. Such emulsions can be sensitized by mechanically-introducing gas bubbles into the emulsion. Resistance to gas bubble migration and coalescence can be achieved by homogenization, without the need for bubble stabilization agents.

Inventors

  • HALANDER JOHN B
  • NELSON CASEY L
  • KOME CORNELIS L

Assignees

  • DYNO NOBEL INC

Dates

Publication Date
20190801
Application Date
20190125
Priority Date
20180129

Claims (20)

  1. 1. A method of delivering an emulsion explosive, the method comprising: obtaining an emulsion matrix comprising a discontinuous phase of oxidizer salt solution droplets in a continuous phase of a fuel, wherein the emulsion matrix has an initial viscosity of about 4,000 cP to about 20,000 cP; mechanically introducing gas bubbles into the emulsion matrix to sensitize the emulsion matrix and form an emulsion explosive; and homogenizing the emulsion explosive to form a homogenized emulsion explosive with a viscosity of greater than or equal to 80,000 cP and that is devoid of an additive that stabilizes gas bubbles.
  2. 2. The method of claim 1, wherein homogenizing the emulsion explosive comprises subjecting the emulsion explosive to shear stress.
  3. 3. The method of claim 2, wherein subjecting the emulsion to shear stress comprises delivering the emulsion through a shearing device.
  4. 4. The method of any one of claims 1-3, wherein the fuel comprises fuel oil.
  5. 5. The method of any one of claims 1-4, wherein fewer than 10% of the gas bubbles that are in the emulsion immediately after homogenization coalesce with other bubbles within 3 minutes after homogenization.
  6. 6. The method of any one of claims 1-5, wherein the gas is nitrogen, helium, a noble gas, air, carbon dioxide, or combinations thereof.
  7. 7. The method of any one of claims 1-6, wherein mechanically introducing a gas into the emulsion comprises delivering gas bubbles about 5 microns or less in diameter or about 1 micron or less in diameter.
  8. 8. The method of any one of claims 1-7, wherein mechanically introducing a gas into the emulsion comprises delivering compressed gas through a porous member into the emulsion.
  9. 9. The method of claim 8, wherein the porous member comprises one or more of a porous ceramic, a sintered steel, or a sintered glass.
  10. 10. The method of any one of claims 1-9, wherein the continuous phase comprises an emulsifier, a homogenization agent, or combinations thereof
  11. 11. The method of any one of claims 1-10, further comprising pumping the emulsion matrix to provide at least a portion of the pressure necessary to homogenize the emulsion explosive.
  12. 12. The method of any one of claims 1-11, wherein the steps of (1) mechanically introducing gas bubbles into the emulsion matrix to sensitize the emulsion matrix and form an emulsion explosive; and (2) homogenizing the emulsion explosive to form the homogenized emulsion explosive both occur on a single mobile processing unit.
  13. 13. The method of any one of claims 1-12, further comprising flowing the homogenized emulsion explosive through a conduit into a borehole. CA 03088893 2020-07-03 WO 2019/147999 PCT/US2019/015241
  14. 14. A homogenized emulsion explosive made by the method of claim 1.
  15. 15. A method of delivering an emulsion explosive, the method comprising: splitting an oxidizer salt solution into a first portion and a second portion; mixing the first portion of the oxidizer salt solution with a fuel to form a low viscosity fuel- rich emulsion matrix, wherein the fuel is substantially devoid of an additive that stabilizes gas bubbles; mechanically introducing gas bubbles into the preliminary emulsion matrix to sensitize the fuel-rich emulsion matrix and form a fuel-rich emulsion explosive; mixing the second portion of the oxidizer salt solution into the fuel-rich emulsion explosive to form a more-balanced emulsion explosive with increased viscosity; and homogenizing the more-balanced emulsion explosive to form a homogenized emulsion explosive with further increased viscosity.
  16. 16. The method of claim 15, wherein the fuel-rich emulsion matrix is formed to have an initial viscosity of about 20,000 cP or less.
  17. 17. The method of claim 15 or claim 16, further comprising homogenizing the more-balanced emulsion explosive until the homogenized emulsion explosive has a viscosity of greater than or equal to about 80,000 cP.
  18. 18. The method of any one of claims 15-17, wherein mechanically introducing gas bubbles comprises diffusing microbubbles with a median bubble size of about 1 to 10 microns.
  19. 19. The method of any one of claims 15-18, wherein the more-balanced emulsion explosive has increased viscosity by more than 6,000 cP, relative to the fuel-rich emulsion matrix.
  20. 20. The method of any one of claims 15-19, wherein the second portion of the oxidizer salt solution is about 45% to about 80%, about 50% to about 70%, of the total amount of the oxidizer salt solution, on a weight-per-weight basis.

Description

CA 03088893 2020-07-03WO 2019/147999 PCT/US2019/015241MECHANICALLY-GASSED EMULSION EXPLOSIVES AND METHODS RELATEDTHERETOTECHNICAL FIELD[0001] The present disclosure relates generally to the field of explosive compositions. More particularly, the present disclosure relates to mechanically-gassed emulsion explosives and methods related thereto.BRIEF DESCRIPTION OF THE DRAWINGS [0002] The written disclosure herein describes illustrative embodiments that are non-limiting and non-exhaustive. Reference is made to certain of such illustrative embodiments that are depicted in the figures, in which: [0003] FIG. 1 is a schematic diagram illustrating one embodiment of a process flow for manufacturing mechanically-gassed emulsion explosive. [0004] FIG. 2 is another schematic diagram illustrating another embodiment of a process flowfor manufacturing a mechanically-gassed emulsion explosive.DETAILED DESCRIPTION [0005] This disclosure generally relates to water-in-oil (or melt-in-oil) emulsions for use as explosives, along with related methods. The term "water-in-oil" means a dispersion of droplets of an aqueous solution or water-miscible melt (the discontinuous phase) in an oil or water-immiscible organic substance (the continuous phase). The water-in-oil emulsion explosives of this invention contain a water-immiscible organic fuel as the continuous phase and an emulsified inorganic oxidizer salt solution or melt as the discontinuous phase. (The terms "solution" or "melt" hereafter shall be used interchangeably.) [0006] Emulsion explosives are commonly used in the mining, quarrying, and excavation industries for breaking rocks and ore. Generally, a hole, referred to as a "blasthole" or "borehole," is drilled in a surface, such as the ground. Emulsion explosives may then be pumped or augered into the blasthole. Emulsion explosives are generally transported to a job site or made on the job site as an emulsion that is too dense to completely detonate, referred to as an emulsion matrix. The emulsion matrix is not considered an explosive. In general, the emulsion matrix needs to be "sensitized" in order for the emulsion matrix to detonate successfully. A sensitized emulsion matrix is considered an emulsion explosive. [0007] Sensitizing is often accomplished by introducing small voids into the emulsion matrix. These voids act as hot spots for propagating detonation. These voids may be introduced by injecting a gas into the emulsion and thereby forming discrete gas bubbles, adding microspheres, other porous media, and/or injecting chemical gassing agents to react in the emulsion and thereby form discrete gas bubbles.1CA 03088893 2020-07-03WO 2019/147999 PCT/US2019/015241 [0008] The emulsion matrix can be designed to be repumpable. A repumpable emulsion matrix can be manufactured at a facility and then pumped into a storage reservoir of a mobile processing unit (e.g., transport truck). The repumpable emulsion matrix can then be safely and economically pumped again on the mobile processing unit to provide sufficient kinetic energy to process the emulsion matrix into an emulsion explosive and delivery the emulsion explosive to a borehole. [0009] The emulsion matrix can also be manufactured on site. This is referred to as site-mixed emulsion matrix. Site-mixed emulsion matrix may not necessarily be designed to be repumpable. Instead, for example, the emulsion matrix may be manufactured under sufficient pressure so that residual pressure provides sufficient kinetic energy to complete processing of the emulsion matrix into an emulsion explosive and deliver the emulsion explosive to a borehole. [0010] In the present disclosure, the introduction of gas bubbles into the emulsion matrix may be accomplished mechanically, such as via compressed gas that is delivered to the emulsion matrix through a porous member of a diffuser. The sensitized emulsion explosive may then be subjected to shear stress, thereby increasing the viscosity of the emulsion explosive. The resulting homogenized emulsion explosive may be used for any suitable purpose, such as for detonation in boreholes. In some embodiments, the homogenized emulsion explosive lacks or is substantially devoid of gas bubble stabilizing agents, such as haloalkyl esters, small particles, and proteins. In some embodiments, the homogenized emulsion includes emulsifiers, homogenizing agents, or both. Specific features of particular embodiments of this disclosure are discussed in additional detail below. [0011] The phrase "fluid communication" is used in its ordinary sense, and is broad enough to refer to arrangements in which a fluid (e.g., a gas or a liquid) can flow from one element to another element. The phrase "bubble stabilizing agent" or "foaming agent" refers to a composition that reduces the rate of bubble coalescence in a gas-infused emulsion relative to an essentia