Classifications

• • C—CHEMISTRY; METALLURGY
  • C06—EXPLOSIVES; MATCHES
  • C06B—EXPLOSIVES OR THERMIC COMPOSITIONS; MANUFACTURE THEREOF; USE OF SINGLE SUBSTANCES AS EXPLOSIVES
  • C06B47/00—Compositions in which the components are separately stored until the moment of burning or explosion, e.g. "Sprengel"-type explosives; Suspensions of solid component in a normally non-explosive liquid phase, including a thickened aqueous phase
  • C06B47/14—Compositions in which the components are separately stored until the moment of burning or explosion, e.g. "Sprengel"-type explosives; Suspensions of solid component in a normally non-explosive liquid phase, including a thickened aqueous phase comprising a solid component and an aqueous phase

Definitions

• a thickening agent for an aqueous slurry explosive composition comprises the combination of a cross-linked galactomannan with psyllium flour in specific proportions, which thickener provides good fluidity and reduced tackiness,
• This invention relates to water-bearing explosive compositions comprising essentially an inorganic oxygen'supplying salt, a fuel, a thickener and water. in particular, the invention relates to a means whereby the thickening of such explosive compositions may be substantially improved.
• Explosive compositions comprising an oxygen-supplying salt such as, for example, ammonium nitrate, and a fuel together with a fluid solvent, disperser or carrier such as water, are known. These compositions are commonly referred to as slurry explosive compositions or, more generally, as slurry explosives.
• Slurry explosives of the aforementioned types normally contain as essential ingredients.widely known power-enhancing materials and fuels such as, for example, finely divided light metal, finely divided carbon and the like.
• power-enhancing materials and fuels such as, for example, finely divided light metal, finely divided carbon and the like.
• a self explosive fuel ingredient such as particulate TNT, PETN, or smokeless powder to further improve the sensitivity and/or strength, thereby insuring detonation and propagation.
• water-bearing explosive slurry compositions wherein water comprises the greater proportion of the fluid carried or disperser for the solid ingredients of the explosive mixture. While these waterbearing slurry explosives possess many advantages such as economy in manufacture and use and reduced hazard, they are at the same time generally susceptible to the segregation of the solid and liquid ingredients both when packaged in containers and when placed directly into the borehole. These slurry explosives are also subject to dilution by water which may be present in the borehole which water may leach out watersoluble ingredients and result in possible detonation failure.
• thickening or gelling agents which have been employed with varying degrees of success, either along or in combination, in water-bearing explosive slurries.
• galactomannan polysaccharide guar gum pregelatinized starches, hydroxyethylcellulose, carboxymethylcellulose, tamarind seed flour and hydrophilic vinyl polymers, such as, for example, polyacrylamide.
• the most widely used of these thickening agents have been the galactomannans, particularly guar gum.
• a water-bearing explosive slurry composition may be provided which will not segregate over long periods of storage, is highly water resistant and yet may be poured or pumped with little or no adherence to container walls or delivery hoses.
• the improved explosive composition of this invention comprises essentially at least one inorganic oxygen-supplying salt, a fuel, water and a thickener, the thickener comprising the combination of cross-linked galactomannan with psyllium flour, the ratio of galactomannan to psyllium flour being from about 1:20 to 5:1 and preferably from 1:10 to 2:1.
• psyllium flour is generally meant the carbohydrate gum of psyllium seed husks, which husks have preferably been ground to a powdery consistency Additionally, the gum may be obtained by water extraction of the psyllium seed or husks, dried and ground.
• the gum of psyllium seed husks has been referred to as a xylogalactan
• chemical analysis has shown variations in chemical composition depending on the plant species from which the seed husks are taken. Plantago ovata is the most common species from which seed husks are harvested in India but P. arenaria, P. Ianceolara and P. psyllium yield similar gums. North American species such as P. wrighri mm, P.
• psyllium may be further characterized as a mucilaginous material when in solution.
• the galactomannan suitable for use in the composition of the invention is preferably guar gum but other galactomannans such as, for example, locust bean gum, honey locust gum, gum gatto, Kentucky cofi'ee bean guar, Tara and Paloverde gums, etc. may also be usefully employed. Guar gum of the self-cross-linking type may be used. Non-self-cross-linking guar gum when used may be cross-linked by employing any of the well-known conventional cross-linking agents such as, for example, sodium dichromate, potassium dichromate and potassium pyroantimonate as disclosed, for example, in Canadian Pat. No. 729,555 issued on March 8, I966. The faster acting cross-linking agents are especially preferred in plant manufacture and the dichromates are particularly useful either alone or as the first addition of a two step cross-linking process with antimony salt solutions.
• galactomannans such as, for example, locust bean gum, honey locust gum, gum gatto
• Preferred blasting slurry explosive compositions of this invention contain from 15 percent to 83 percent by weight of at least one inorganic oxygen-supplying salt, from 12 percent to 30 percent by weight of water, from 0.2 percent to 2.5 percent by weight of thickener and from 5 percent to 55 percent by weight of fuel. All the slurries of this invention are possessed of a pseudoplastic (shear-dependent) characteristic and the pourable types exhibit viscosities in the ranges shown below in table l when measured at about 72 F. on a Brookfield viscometer, Model RVF equipped with a No. 6 spindle.
• This pseudoplastic nature contributes greatly to preventing the sedimentation of suspended particles under static conditions yet permitting ready pourability and high flow rates with low to moderate increases in shear stress.
• a preferred solvent or carrier for the oxidizing salt is water. However, less then half of the water may be replaced by organic solvents such as formamide, dimethyl sulfoxide and the lower glycols and alcohols. These solvents are polar liquids, readily miscible with water in all proportions and are effective solvents for ammonium nitrate and other inorganic salts and tend to function as fluidizing agents in the mixture.
• the fuels employed in the composition of the invention may be, for example, energetic metals such as aluminum or aluminum alloys, metalloids such as silicon, particulate self-explosive fuels, nonexplosive carbonaceous material such as finely divided carbon or mixtures of these.
• the aluminum or aluminum alloy or other energetic metal or metalloid such as silicon
• the aluminum or aluminum alloy or other energetic metal or metalloid must be in finely divided form and may most suitably range from a fine dust to a form not coarser than that which will pass through a size 6 Tyler mesh screen.
• relatively inexpensive air-atomized powder, shredded foil or granules made from reclaimed scrap are suitable types of aluminum.
• silicon is employed, the fine powder form is used.
• Useful particulate self-explosives which may be used as fuel in the explosive composition include, for example, trinitrotoluene (TNT), pentaerythritol tetranitrate (PETN), cyclotrimethylenetrinitraminc (RDX), composition B (mixture of TNT and RDX), pentolite (mixture of PETN and TNT), smokeless powder, nitrocellulose, nitrostarch and mixtures of these.
• TNT trinitrotoluene
• PETN pentaerythritol tetranitrate
• RDX cyclotrimethylenetrinitraminc
• composition B mixture of TNT and RDX
• pentolite mixed mixture of PETN and TNT
• smokeless powder nitrocellulose, nitrostarch and mixtures of these.
• Suitable carbonaceous fuels include, for example, finely divided coal or carbon, vegetable products such as woodmeal, sugar, ground nut husks, and the like, hydrocarbon oils and similar oleaginous material, urea and mixtures of these.
• the explosive composition may be prepared by processes well known in the art employing simple mixing procedures. In general, the polysaccharide ingredients are hydrated in a mixture of the nitrate salts and water with pH adjustment into the range of 3.1 to 5.5. A mix procedure is adopted which allows good hydration of the guar component before cross-linking becomes too advanced and mixing is usefully carried out at an elevated temperature to reduce the time of hydration. More specific items of procedure are described in the examples, The composition may similarly be employed where a slurry explosive composition is prepared for use at the blasting site by means of the now well-known slurry mix truck although in this case a supply of warm prethickened nitrate salt liquor would be necessary to accomplish practical discharge rates.
• the degree of thickening or gelling and hence the viscosity and fluidity of the slurry explosives compositions of the invention is dependent on the quantity and kind of galactomannan and psyllium employed and on the quantity and type of crosslinking agent used. It will be obvious that variations are possible which will permit the manufacture of explosive slurries having a wide range of gel characteristics.
• the preferred slurry composition is one which is easily pourable or pumpable yet which retains all the water-resistant and antisegregation properties of a thick or dense gel. Slurry explosives of high viscosity may be obtained through the use of a larger percentage by weight of galactomannan and/or a larger quantity of cross-linking agent.
• the psyllium component of the thickener is only very mildly cross-linked by conventional cross-linking agents and hence the psyllium functions to provide fluidity to the gelled mixture and reduce tackiness.
• EXAMPLE I A solution was prepared comprising 30 parts by weight of ammonium nitrate, 12 parts by weight of sodium nitrate and 15 parts by weight of water. The solution was adjusted to a pH of 4.4 with acetic acid and one part by weight of ground psyllium seed husks was added. The ingredients were stirred together for 15 minutes and allowed to stand for hours at 23 C. A second mixture was prepared except that 0.2 part by weight of sodium dichromate cross-linking agent was added. The viscosities of both mixtures were measured with a Brookfield RVT viscometer, No. 6 spindle at l0 rpm. and 72 F. The viscosity of the non-cross-linked mixture was 9,000 cps. and the viscosity of the cross-linked mixture was 13,000 cps. With 5.0 parts of technical grade calcium nitrate, the viscosity increased from 9,000 cps. to 11,000 cps. and even with 0.1
• Potassium pyroantimonate was added in the guar/glycol slurry and mixing was continued for about 15 to 20 minutes at 75 to F.
• An aqueous slurry explosive composition comprising at 4- least one inorganic oxygen-supplying salt, a solvent or carrier TABLE II for the inorganic oxygen-supplying salt, a fuel and a thickener.
• Example 2 3 4 5 said thickener comprising the combination of cross-linked galactomannan with psyllium flour, the ratio of galactomangg ggyfi g 6 5 3 3 g 0 nan t0 psyllium flour being from about I220 to about 5: l. Potassiumpitrat 2.
• Zinc eliminate 3.
• An aqueous slurry explosive composition comprising gi g gg y g igfi f 668E513) from about 15 percent to about 83 percent by weight of an in- Dissolved urea I organic oxygen-supplying salt, from about l2 percent to about Egggg$ percent by weight of a solvent or carrier for the inorganic grade) Q16 oxygen-supplying salt, from about 5 percent to about 55 perfl ggf (51181 cent by weight of a fuel and from about 0.2 percent to about P i ss lum pyroantlmonate 2.5 percent by weight of a thickener, said thickener comprissodllllll dgchwmate mg the combination of cross-linked galactomannan to psylli- 3,5;,;5 ;,g um
• Ammoniumllgnosulphonate ... 0.10 0 10 2,0 consisting of the nitrates of ammonium, sodium, potassium, ggc hlgig i el ylene (sensltizer)- n 5 barium, calcium and mixtures thereof. Aluminum same; 1 ,0 "i513 30 5.

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• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Liquid Carbonaceous Fuels (AREA)
• Solid Fuels And Fuel-Associated Substances (AREA)
• Compositions Of Macromolecular Compounds (AREA)
• Polysaccharides And Polysaccharide Derivatives (AREA)

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Country Status (13)

Cited By (5)

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Citations (5)

• 1969
  • 1969-09-09 GB GB44436/69A patent/GB1200860A/en not_active Expired
  • 1969-09-11 IE IE1274/69A patent/IE33579B1/xx unknown
  • 1969-09-12 NO NO3657/69A patent/NO120624B/no unknown
  • 1969-09-15 US US858143A patent/US3617407A/en not_active Expired - Lifetime
  • 1969-09-18 ZA ZA696594A patent/ZA696594B/xx unknown
  • 1969-09-30 ZM ZM150/69A patent/ZM15069A1/xx unknown
  • 1969-09-30 BR BR212867/69A patent/BR6912867D0/pt unknown
  • 1969-09-30 BE BE739617D patent/BE739617A/xx unknown
  • 1969-10-06 OA OA53746A patent/OA03146A/xx unknown
  • 1969-10-07 FR FR6934193A patent/FR2027519A1/fr not_active Withdrawn
  • 1969-10-07 ES ES372252A patent/ES372252A1/es not_active Expired
  • 1969-10-07 DE DE19691950580 patent/DE1950580B2/de active Granted
  • 1969-10-07 CH CH1504669A patent/CH538436A/de not_active IP Right Cessation

Patent Citations (5)

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