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
  • C06B47/145—Water in oil emulsion type explosives in which a carbonaceous fuel forms the continuous phase
• • C—CHEMISTRY; METALLURGY
  • C06—EXPLOSIVES; MATCHES
  • C06B—EXPLOSIVES OR THERMIC COMPOSITIONS; MANUFACTURE THEREOF; USE OF SINGLE SUBSTANCES AS EXPLOSIVES
  • C06B43/00—Compositions characterised by explosive or thermic constituents not provided for in groups C06B25/00 - C06B41/00

Definitions

• This invention relates to emulsion type blasting agents having a discontinuous phase and a carbonaceous fuel component forming a continuous phase.
• Emulsion.type blasting agents are well known commercial explosive compositions but they are generally detonable only with difficulty and it is usual, therefore, to incorporate in them a sensitizing agent in the form of a gas, for example air, either in the form of bubbles or in microspheres of glass or plastic.
• a sensitizing agent in the form of a gas, for example air, either in the form of bubbles or in microspheres of glass or plastic.
• conventional EBA's commonly comprise a discontinuous aqueous phase consisting of a solution of.oxidiser salts, often also containing oxidiser salts suspended as fine particles, in a continuous oil phase and containing also a third, gaseous, phase dispersed in the emulsion as gas bubbles.
• the emulsion is stabilised against liquid separation by a lipophilic emulsifying agent.
• Such emulsions can also served as detonable matrices to carry solid fuelds such as aluminium or inorganic oxidising agents of low solubility.
• EBA's typically can be made in a variety of forms from stiff plastic creams to almost fluid pumpable compositions and a stiff cream consistency is usually preferred.
• EBA's commonly have an intrinsic density in the region of 1.45 gm/cc, the occluded gas reducing this to 1.2 gm/cc or less, and the sensitivity of the gas containing EBA is inversely related to its density for a given chemical composition.
• gas bubbles are included in the emulsion they tend to coalesce, reducing the detonability of the composition, and this is sometimes overcome by incorporating the gas enclosed in microspheres of glass or other material.
• the use of such additional components increases the cost of the composition significantly.
• the present invention provides an emulsion type blasting agent comprising a discontinuous phase and a carbonaceous fuel component forming a continuous phase, in which the discontinuous phase comprises an aqueous solution of urea perchlorate.
• the aqueous phase optionally may comprise other compatible water-soluble materials, particularly inorganic oxidising materials, for example ammonium salts, alkali metal and alkaline earth metal salts, in particular the nitrate, chlorate and perchlorate salts, such as are mentioned for example in US Pazent No. 3,447,978 and other literature, and hydrazine nitrate.
• inorganic oxidising materials for example ammonium salts, alkali metal and alkaline earth metal salts, in particular the nitrate, chlorate and perchlorate salts, such as are mentioned for example in US Pazent No. 3,447,978 and other literature, and hydrazine nitrate.
• inorganic oxidising materials for example ammonium salts, alkali metal and alkaline earth metal salts, in particular the nitrate, chlorate and perchlorate salts, such as are mentioned for example in US Pazent No. 3,447,978 and other literature, and hydrazin
• urea nitrate is only sparingly soluble in water and it is preferred therefore that if a soluble nitrate is included in the composition it will only be present in such amount that the emulsification of the composition is not unduly impaired by formation of solid urea nitrate.
• the aqueous component of the emulsion is usually formed by heating the water and dissolving in it the desired water soluble components.
• the mixture is usually heated to 50 o C, or such other temperature as is appropriate, until complete solution occurs and heating may be effected prior to or during formation of the emulsion.
• the proportions of solvent and solute are so chosen that in the final emulsion, after it has been cooled to ambient temperature, the aqueous component is supersaturated, although some crystallisation, resulting in the presence of crystals in the aqueous component, may not adversely affect the properties of the blasting agent unduly.
• the aqueous phase may comprise also water soluble fuel components to serve as supplemental fuels.
• soluble carbohydrate materials e.g. glucose, sucrose, fructose, maltose, molasses, lower glycols, formamide, urea, methylamine nitrate, hexamethylene tetramine, hexamethylene tetramine nitrate, and other organic nitrates, etc.
• the urea perchlorate conveniently is present in the discontinuous phase of the EBA of the invention in an amount forming from about 20 to about 95%, preferably at least 30% and more preferably at least 50% of the discontinuous phase, although usually it will exceed 70% and more usually 80% or even 90% or 95% by weight of the discontinuous phase.
• the use of relatively low levels of urea perchlorate, for example below 60% may require the presence of auxiliary oxidiser components to provide the required detonation characteristics.
• the discontinuous phase may form from about 20 to about 97%, although usually it will form more than 4 0 %; preferably more than 60% and more preferably more than 80% by weight of the EBA.
• the precise proportion will, of course, depend upon the amount of other ingredient present, to 100%.
• the second component of the EBA of the invention is a carbonaceous fuel component forming a continuous phase.
• a component must be non-water soluble and must be capable of forming a water-in-oil emulsion with the aqueous component when an appropriate emulsifying agent is present in suitable quantity.
• the fuel component must be capable of being rendered fluid to permit formation of the emulsion.
• it may be desirable for the emulsion as finally prepared to have a solid or near solid continuous phase it will usually be necessary for it to be capble of being rendered sufficiently liquid by raising its temperature to an appropriate level to enable emulsification to occur.
• the carbonaceous fuel component preferably includes a wax and an oil component e.g. an intimate oil/wax mixture, or a wax polymeric modified oil component.
• the fuel component may thus include hydrocarbons whether paraffinic or olefinic, naphthenic, aromatic saturated or unsaturated.
• Waxes which may form part of the carbonaceous fuel component include waxes derived from petroleum, mineral waxes, animal waxes, and insect waxes.
• the preferred waxes are those which have melting points of at least 30°C and which are readily compatible with the formed emulsion.
• the waxes Preferably have a melting point in the range 40 0 C to 75°C.
• a petroleum of a suitable viscosity may be used as a component of the carbonaceous fuel and typical materials for this purpose may have Brookfield viscosities at 30°C in the range 160 to 5000 centipoises.
• Non-volatile, water insoluble polymeric or elastomeric materials such as natural rubber, synthetic rubber and polyisobutylene may be included in the fuel component, as may also be copolymers, for example of butadiene-styrene, of isopren-isobutylene, or of isobutylene-ethylene.
• the carbonaceous fuel component is generally present in an amount from 2 to 8 parts by weight per 100 parts by weight of the EBA, although higher proportions for example up to 10, 15 or even 20% may be employed.
• Supplementary fuels which may be included in the carbonaceous fuel component include fatty acids, higher alcohols, vegetable oils, nitro organic compounds, both aliphatic and aromatic, e.g. dinitrotoluene, nitrate esters, solid particulate materials for example coal, graphite, carbon, sulphur, aluminium, magnesium, etc.
• gas in some form, either as gas micro-bubbles or as gas in microspheres of glass or other material e.g. Perlite, in which case it will be usual to include the gas, usually air, by any suitable known means.
• the gas component is usually added during cooling such that the prepared emulsion comprises from about 0.05 to 50% by volume of gas at ambient temperature and pressure.
• gas of bubble diameter below 200 ⁇ m, preferably below 100 ⁇ m, more preferably between 20 and 90 ⁇ m and particularly between 40 to 70 ⁇ m, in proportions less than 10%, preferably less than 7%, more preferably less than 5%, and particularly less than 3% or even 1% by volume.
• at least 50% of the occluded gas will be in the form of bubbles of microspheres of 20 to 90 ⁇ m, preferably 40 to 70 ⁇ m internal diameter.
• gas is included in the composition in the free state, as distinct from enclosed within microspheres it will usually be introduced simply by mixing the emulsion in an open vessel, although it may also be included by bubbling the gas through the emulsion or by chemical generation of the gas in situ. Suitable techniques are described in the literature.
• the EBA of the invention also comprises means for effecting stable emulsification of the components.
• a water-in-oil type surfactant or emulsifying agent is used in a proportion appropriate to the requirement to produce a sufficiently permanent emulsion.
• the surfactant is used in an amount of 0.5 parts to 5 parts by weight per 100 parts by weight of the EBA though the proportion for any particular composition can easily be determined by experiment.
• surfactants include for example those derived from sorbitol by esterification, the glycerides of fat-forming fatty acids, the polyoxyethylene sorbitol esters, the isopropyl esters of lanolin fatty acids, mixtures of higher molecular weight fatty alcohols and wax esters, polyoxyethylene(4) lauryl ether, polyoxyethylene(2) oleyl ether, polyoxyethylene(2) stearyl ether, polyoxyalkylene oleyl/ laurate, oleyl acid phosphate, substituted oxazolines and phosphate esters etc. Mixtures of such surfactants may also be used.
• the EBA of the invention may be prepared typically by mixing water with the urea perchlorate and, where present, other oxidising agents to form a solution. Dissolution and preparation of a saturated solution may be facilitated by heating the water, though we do not exclude the possibility that all or most of the ingredient of the emulsions may be mixed together and heated together. The emulsifier and fuel are then added at an appropriate temperature and the resulting mixture agitated to produce the required emulsion. Other ingredients,-particularly solids, are conveniently, though not essentially, added and further agitation applied.
• the EBA's of the invention can be used as such, or they may be packaged into charges of convenient dimensions.
• compositions were made by the conventional technique of preparing an aqueous solution of the urea perchlorate and any other water soluble components at a suitably elevated temperature.
• the emulsifier and fuel were then mixed with the aqueous solution and the whole submitted to thorough agitation to produce the desired emulsion.
• appropriate air in the form of Microballoons, was also incorporated and distributed thoroughly by further agitation.
• Example 6 the temperature was 5°C; for the remaining Examples the temperature was 25°C.
• Kaydol Oil is a white mineral oil of high purity supplied by Witco Chemical Company. "Microballoons" is a Registered Trade Mark
• a No. 6 Detonator is an Instant Electric No. 6 detonator having a base charge of 0.24 gm PETN and initiating charge of 0.15 gm ASA.
• a No. 8 detonator is an Instant Electric No. 8 detonator having a base charge of 0.45 gm PETN and initiating charge of 0.15 gm ASA.

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• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Oil, Petroleum & Natural Gas (AREA)
• Colloid Chemistry (AREA)
• Liquid Carbonaceous Fuels (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
• Cosmetics (AREA)

Applications Claiming Priority (2)

Publications (2)

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Cited By (4)

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Citations (8)

• 1981
  • 1981-07-09 EP EP81303137A patent/EP0044671A3/fr not_active Withdrawn
  • 1981-07-09 GB GB8121236A patent/GB2080280B/en not_active Expired
  • 1981-07-15 ZW ZW167/81A patent/ZW16781A1/xx unknown
  • 1981-07-16 NZ NZ197739A patent/NZ197739A/en unknown
  • 1981-07-17 ZA ZA814927A patent/ZA814927B/xx unknown
  • 1981-07-20 NO NO812482A patent/NO812482L/no unknown
  • 1981-07-20 AU AU73126/81A patent/AU555886B2/en not_active Ceased

Patent Citations (8)

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