AU748696B2 - Explosive emulsion composition - Google Patents

Description

WO 00/17130 PCT/AU99/00792 1 EXPLOSIVE EMULSION COMPOSITION TECHNICAL FIELD This invention relates to an explosive composition of the kind comprising a discontinuous oxidiser phase dispersed throughout a continuous fuel phase which is substantially immiscible within the discontinuous phase..

BACKGROUND ART Commercially available emulsion explosive composition generally comprise an external or continuous organic fuel phase in which discrete droplets of an aqueous solution of an oxidiser-supplying-source are dispersed as an internal or discontinuous phase. Emulsion explosive compositions may be manufactured with in-line motionless mixers and any type of mixers able to disperse discontinuous phase into fine droplets -which have a typical size range of about 1 to 20 microns. In order to achieve such fine droplet distribution the inclusion of a suitable emulsifier in the mixture is deemed essential. The emulsifier is selected to promote a subdivision of the dropletsof the oxidiser phase and dispersion thereof in the continuous-phase.

As background to this invention, reference is made to the following prior art: AU 35220/93 (The Lubrizol Corporation); AU 29932/89 (ICI Australia Operations Proprietary Limited); AU 33027/93 (ICI Canada Inc.) and AU 78385/95 (Atlas Powder Company).

DISCLOSURE OF THE INVENTION It is an object of this invention to provide an explosive emulsion composition which goes at least some way towards overcoming or at least minimising prior art problems of chemical incompatibility, or for providing a clear altemrnative choice for users of such compositions.

Other objects of this invention will become more apparent from the following description: According to one aspect of the present invention, there is provided a water-in-oil explosive composition comprising an aqueous oxygen-releasing salt solution with the presence of anti-caking and stabilising agents as a discontinuous phase, wherein said oxygen-releasing salt solution consists essentially of Ammonium Nitrate from the group of KT (Kaltenbach-Thuring) type of Ammonium Nitrate prill, and said anticaking agents are selected from the group of aromatic alkyl sulfonates; and a continuous water-immiscible organic phase comprising of an emulsifying agent, an emulsifier selected from the group consisting of poly (isobutylene) succinic anhydride or poly (isobutylene) succinic acid which has been derivatised with amine or alkanolamine.

o More specifically, the present invention provides an explosive composition comprising 15 an oxygen-releasing salt solution with the presence of anti-caking and stabilising agents as a discontinuous phase, wherein said oxygen-releasing salt solution consists essentially of Ammonium Nitrate from the group of KT (Kaltenbach-Thuring) type Ammonium Nitrate prill, and wherein the anti-caking agent is from the group of S. alkylarylsulfonates and the stabilising agent is from the group of arylsulfonate salts, a 20 continuous water-immiscible organic phase comprising of an emulsifying agent, an emulsifier or emulsifiers selected from the group consisting of poly (isobutylene) succinic anhydride or poly (isobutylene) succinic which has been derivatised with amine or alkanolamine, preferably the combination of derivatives of triethanolamine and diethylethanolamine with poly (isobutylene) succinic anhydride or poly (isobutylene) succinic acid. Preferably, the emulsifier comprises from 0.1% to about by weight of the total composition.

PCT/AU99/00792 Received 9 May 2000 3 The oxidiser salt or salts are preferably selected from the group consisting of ammonium, alkali-earth and alkali metal nitrates. Preferably, the oxidiser salt is Ammonium Nitrate (AN) alone or in combination with Calcium Nitrate (CN) or Sodium Nitrate The amount of oxidiser salt employed is generally from about 45% to about 94% by weight of the total composition, and preferably from about to about 85%. The source of AN is conventionally specially made for emulsion preparation, which could be as liquor, crystalline, or pelleted and is not suitable for use as a dry addition or as "ANFO". This invention permits the use of conventional AN sources as well as the use of prilled AN (PAN), as commonly used for explosives in the form of ANFO, a mixture of AN and fuel oil. There are several styles of such prilled AN commercially available, such as TOPAN or Kaltenbach-Thuring (KT).

The present invention makes use of, but is not limited to, the latter prilled AN style, which may be used without any pre-treatment in the oxidiser phase. The KT PAN uses internal water-soluble additives consisting of alkylarylsulfonates, which may be commercially available as "GALORYL 725ATH", and uses oil soluble external or surface coatings as anti-caking agents, which may be commercially available as "GALORYL 626M". The "GALORYL" additives are usually considered poisonous to emulsions if included in the oxidiser phase, however the present invention permits their uSe.

The immiscible liquid organic fuel forming the continuous phase of the composition is present in the amount of from about 3% to 13%, and preferably from 5% to 9% by weight of this total composition. Suitable organic media include saturated or unsaturated aliphatic, alicyclic and/or aromatic hydrocarbons, and mixtures of them.

Preferred media include refined (white) mineral oil, diesel oil, petroleum distillates, benzene, toluene, styrene, xylenes, and mixtures thereof.

The water content usually comprises from 7% to 30%, preferably from 14% to 19% by weight of the total composition. The oxidiser phase of the composition may comprise urea, usually in the range of 0% to about 15%, preferably from 3% to 9% by weight of the total composition.

AMENDED SHEET

IPEA/AU

Received 9 May 2000 4 The invention also provides a process for preparation of water-in-oil explosive emulsion compositions which comprise a discontinuous phase comprising of oxygenreleasing salts and urea, a continuous water-immiscible fuel phase comprising PIBSA derived emulsifiers as emulsifying agents with oils, which process comprises: a) dissolving said oxygen- releasing salts in water at a temperature above the fudge point of the aqueous salts solution with the acidity between pH 2.0 7.0, preferably between pH 3.5 6.0 and most preferably between pH 5.0 5.5; and b) mixing said aqueous salts solution and said fuel phase comprising of derivatives of PIBSA emulsifier(s) and oil(s) to desired viscosity.

BEST MODE OF CARRYING OUT THE INVENTION In one preferred form of the invention the explosive emulsion composition comprises so-called dry addition up to 95% of the total composition weight. In a preferred form, the dry addition comprises Ammonium Nitrate, or a blend of Ammonium Nitrate and diesel oil.

AMENDED SHEET

IPEA(AU

.WO 00/17130 WO 0017130PCT/AU99/00792 Example of Emulsiprill Formulation OXIDISER/FUEL RATIO: 93.5 6.5 VISCOSITY SPEC: (spindle 7 28000 t 1000 65 0

C

COMPONENT PERCENTAGE MASS (g)

LIQUOR

AN (KT prill or liquor) Urea N9 H20 75.00 5.00 0.30 19.65 70.13 4.68 0.28 18.37 Citric 0.05 0.05 TOTAL 100.00 93.50 Temnp 65 +2' 1

C--

PH

FUEL

N44 8.00 0.52 MCP1517 P12 D FO 8 00- 30.00 54.00 0.52 1.95 3.51 TOTAL 100.00 6.50 100.00 TOTAL TEMP 55 t 2cC cP of Oxidiser 47 -48 'C Specific gravity 1.365 g/cm3 Hot density 1.32 g/cm3 Cold density 1.34 glcm3 Capacitance (hot matrix) 150 -170 pF WO 00/17130 PCT/AU99/00792 6 Opposed to conventional wisdom and other inventions including those referred to Patent No: AU-A-78385/9, Atlas Powder Company and, Patent No: AU-A-35220/93, The Lubrizol Corporation this invention specifically permits the use of Ammonium Nitrate prill (KT, Kaltenbach-Thuring type of prill that uses Galoryl 725ATH and Galoryl 626M) in the oxidiser phase to make an emulsion composition, and the use of the same type of prill for "so called" dry addition, to make very stable explosive composition blends.

Furthermore this invention permits the use of a large range of gassing chemicals in the explosive composition blends to produce fine gas bubbles as density reducing agents Apart from gas bubbles as a density reducing agent, this invention allows use of other selected materials such as hollow particles or microballoons, porous particles or mixtures thereof. They are usually present in an amount to give a composition having a density in the range of about 0.30 to 1.50 g/cm 3 The invention will now be further described with reference to the following nonlimiting examples as shown in Tables 1 and 2.

Table I demonstrates the preference of formulation 4, wherein the pH is set at the preferable value of 5.5, and the sodium thiocyanate is set at 0.15% of the oxidiser phase. Note that the oxidiser phase components add to 100%, these being ammonium nitrate consisting of KT prills, 5% of urea, 19.85% of water, 0.15% of sodium thiocyanate, 0.025% of citric acid. This oxidiser is mixed with fuel phase in the ratio of 94/6 respectively, the fuel phase consisting of 8% diethylethanolamine WO 00/17130 PCT/AU99/00792 7 derivative of PIPSA, 8% triethanolamine derivative of PIBSA, 54% of diesel fuel oil #2.and 30% of light mineral oil. The resulting explosive emulsion is stable for more thain6 months when unblended or unsensitised. In this example, the emulsion is blended with 30% ANFO made from KT prill and fuel oil and gassed. This gassed sensitised formulation is shown to be superior to the other examples having stability rating of 6 after 14 days, which is very good. The stability scale varies from 9, which is excellent no crystallisation, through 4 which is highly crystallised on the point of non-detonateability, to zero which is completely crystallised or broken.

Note that although the-preferred fuel phase is used throughout table 1, good stability is only achieved when the pH is in the range 5.0 to 5.5, sodium thiocyanate is in the range 0.10% to 0.15%, and. urea is in the range 3 to here set at Table 2 demonstrates the effect of preferred fuel phase components. Here emulsifier 1 is a derivative of diethylethanolamine and PIBSA, emulsifier 2 is a-derivative of triethanolamine and PIBSA, emulsifier 3 is a derivative of diethanolamine and PIBSA, and emulsifier 4 is a derivative of tris-hydroxymethylamino methane and PIBSA. Only the combination of emulsifier 1 and emulsifier 2 gives a good overall result, even if the preferred oxidiser phase is used as in this table, as shown in formulation 15. If only emulsifier 1 is used as in formulation 13, the resulting emulsion continuously thickens and causes pumping problems. If only emulsifier 2 is used as in formulation 14, the emulsion thins too easily when gassed, losing sensitisation. In addition, the stability rating for formulations 13 and 14 is less than the combination in formulation 15 which rates a 7 (very good) after 10 days, while the other examples rate a 4 which is on the threshold of failure. Ten days is deemed to be a satisfactory period for a useful application of such explosives. Similarly, the other examples in formulations 16 and 17 show weaknesses in the pumped gassed blends which actually failed when under field trials by losing sensitisation. Example 18 did not even form an emulsion even though this emulsifier is well known in the art.

WO 00/17130 PCT/AU99/00792 8 Although exemplary embodiments of the present invention have been shown and described, it will be apparent to those having ordinary skill in the art that a number of changes, modifications or alterations to the invention described herein may be made, none of which depart from the spirit of the present invention. All such changes, modifications, and alterations should therefore be seen as being within the scope of the present invention.

It should be appreciated that the present invention provides a substantial advance in explosive emulsion compositions providing all of the herein-described advantages without incurring any relative disadvantages.

Claims (21)

1. A water-in-oil explosive composition comprising an aqueous oxygen- releasing salt solution with the presence of anti-caking and stabilising agents as a discontinuous phase, wherein said oxygen-releasing salt solution consists essentially of Ammonium Nitrate from the group of KT (Kaltenbach-Thuring) type of Ammonium Nitrate prill, and said anti-caking agents are selected from the group of aromatic alkyl sulfonates; and a continuous water-immiscible organic phase comprising of an emulsifying agent, an emulsifier selected from the group consisting of poly (isobutylene) succinic anhydride or poly (isobutylene) succinic acid which has been derivatised with amine or alkanolamine.

2. An explosive comprising of oxygen-releasing salts with the presence of anti- 15 caking and stabilising agents as a discontinuous phase, wherein said oxygen- releasing salt solution consists essentially of Ammonium Nitrate from the group of KT (Kaltenbach-Thuring) type of Ammonium Nitrate prill, and wherein the anti-caking agent is from the group of alkylarylsulfonates and S. 20 the stabilising agent is from the group of arylsulfonate salts, a continuous water-immiscible organic phase comprising of an emulsifying agent, an emulsifier or emulsifiers selected from the group consisting of poly .(isobutylene) succinic anhydride or poly (isobutylene) succinic acid which g has been derivatised with amine or alkanolamine, preferably the combination 25 of derivatives of triethanolamine and diethylethanolamine with poly (isobutylene) succinic anhydride or poly (isobutylene) succinic acid.

3. A composition according to claim 1 or claim 2, wherein the oxygen-releasing salts of said oxygen-releasing salt solution are selected from the group consisting of Ammonium Nitrate, Calcium Nitrate, Sodium Nitrate and mixtures thereof. PCT/AU99/00792 Received 9 May 2000

4. A composition according to any one of the preceding claims, wherein the oxygen-releasing salts component comprises from 60 to 85 by weight of total composition.

5. A composition according to any one of the preceding claims, including Urea in the Oxidiser phase.

6. A composition according to claim 5, wherein Urea comprises from 0 to 15 preferably 3 to 9 by weight of the total composition.

7. A composition according to any one of the preceding claims, wherein the Ammonium Nitrate additive and the anti-caking agent are selected from the group of the salts of alkylarylsulfonate in the amount up to 0.6 by weight of total composition.

8. A composition according to any one of the preceding claims, wherein said continuous water-immiscible phase comprise of at least one derivative of poly (isobutylene) succinic anhydride or poly (isobutylene) succinic acid emulsifier with diethylethanolamine or triethanolamine.

9. A composition according to claim 8, wherein the emulsifying agent comprises from 0.1 to 5.0% by weight of the total composition. A composition according to any one of the preceding claims, wherein the water-immiscible continuous phase comprises from 3 to 13 preferably from 5 to 9 by weight of the total composition.

11. A composition according to any one of the preceding claims, wherein said water-immiscible organic phase comprises from 7 to 30 preferably from 14 to 19 by weight of the total composition. SJAMENDED SHEET IC IPEA/AU PCT/AU99/0079 2 Received 9 May 2000 11

12. A composition according to any one of the preceding claims, which includes a catalyst in the oxidiser phase.

13. A composition according to claim 12, wherein the catalyst is selected from the group of thiocyanate products.

14. A composition according to claim 12 or claim 13, wherein the catalyst comprises from 0.1 to I preferably 0.1 to 0.3 of the oxidiser phase, and most preferably 0.1% to 0.18%. An explosive composition according to any one of the preceding claims, which comprises of so called dry addition, whereby said dry addition comprises between 5 to 95 of the total composition weight.

16. An explosive composition according to claim 15, wherein the dry addition is comprised of Ammonium Nitrate prill, or blend of Ammonium Nitrate prill and diesel oil ("ANFO").

17. An explosive composition according to claim 15 or claim 16, wherein said Ammonium Nitrate prill is selected from any type of commercially known Ammonium Nitrate prill regardless of prill description (additive and coatings).

18. An explosive composition according to any one of claims 15, 16 and 17 wherein said Ammonium Nitrate prill includes those known as KT (Kaltenbach-Thuring) type of Ammonium Nitrate prill.

19. An explosive composition according to any one of the preceding claims, further comprising of a density reducing agent. AMENDED SHEET IPEA/AU 12 An explosive composition according to any one of the preceding claims, wherein said density reducing agent is selected from the group of chemicals consisting of fine gas bubbles, hollow particles or microballoons, porous particles or mixtures thereof.

21. An explosive composition according to any one of the preceding claims, wherein sufficient density reducing agent is used to give a composition having a density in the range of 0.30 to 1.50 g/cm3.

22. A process for preparation of water-in-oil explosive emulsion compositions which comprise a continuous phase comprising of oxygen-releasing salts and urea, a continuous water-immiscible fuel phrase comprising PIBSA derived emulsifiers as emulsifying agents with oils, which process comprises: a) dissolving said oxygen-releasing salts in water at a temperature above the fudge point of the aqueous salts solution with the acidity between pH 2.0 preferably between pH 3.5 6.0 and most preferably between pH o° oo 5.5; and o b) mixing said aqueous salts solution and said fuel phase comprising of derivatives of PIBSA emulsifier(s) and oil(s) to desired viscosity. °oooi

23. An explosive composition according to any one of claims 1 to 21, substantially as hereinbefore described and illustrated. ooooo

24. A process for preparation of water-in-oil explosive emulsion composition according to claim 22, substantially as hereinbefore described and illustrated. Dated this 13 t day of March 2001 DYNO NOBEL ASIA PACIFIC LIMITED Al Patent Attorneys for the Applicant HODGKINSON OLD MclNNES