US3653996A - Controlled gelation in aqueous explosives containing boric acid - Google Patents

Abstract

Explosive compositions containing boric acid, a gelling agent, an oxidizer, a fuel component, and an aqueous medium and a method of controlling the degree of gelation of these compositions. The compositions can be gelled to the extent desired by adjusting their pH.

Description

United States Patent [151 3,653,996

Edwards 1 Apr. 4, 1972 [54] CQNTROLLED GELATION IN AQUEOUS EXPLOSIVES CONTAINING References Cited UNITED STATES PATENTS [72] Invent: Edwards 3,072,509 l/l963 Barnhart et a1. ..149/92 x [73] Assignee: Atlas Chemical Industries, Inc., Wilming- 3,330,706 7/1967 Griffith ..149/44 X ton, Del, Primary ExaminerLeland A. Sebastian [22] Flled' 1970 AttorneyKenneth E. Mulford, Roger R. Horton and Ernest [21] Appl. No.: 5,144 G. Almy 52 us. Cl ..149/21, 149/2, 149/38, [57] ABSTRACT 14 l /44, Explosive compositions containing boric acid, a gelling agent, l4 7; '1 an oxidizer, a fuel component, and an'aqueous medium and a 149/77, 149/78, 149/89, l l49/105 method of controlling the degree ofgelation of these composi- [51] Int. Cl. ..C06b 19/04 tions. The compositions can he gelled to the extent desired by [58] Field of Search ..149/92; 149/2, 21, 38, 41, adjusting their PH 27 Claims, N0 Drawings CONTROLLED GELATION IN AQUEOUS EXPLOSIV ES CONTAINING BORIC ACID This invention relates to explosive compositions which are capable of controlled gelation and to a method of controlling the degree of their gelation.

Slurry explosives generally contain a gelling agent such as guar gum to prevent the insoluble components of the explosive from segregating, which would make the explosive insensitive. A cross-linking agent is usually also present to crosslink the gelling agent and form a stable gel; generally, borates and chromates are used as cross-linking agents. These compounds form cohesive gels between a pH of about 5 to about 6. Below about 5 only a thickened mass is produced, and above about 6 the gel becomes so tight that the water is squeezed out. With certain types of gums, a gel cannot be formed at all even at a high pH. But even at a pH of 5 to 6, these gels are not pourable and there is no way to control or vary the degree of gelation. As such, they are difficult to load into a borehole and do not adequately fill all the voids in the borehole, which may result in an inefficient utilization of the explosive.

Since most gelling agents require time to gel, the commercial practice is to use excess gelling agent so that the gelation is complete enough at the end of the mixing stage to prevent segregation of the components. However, in addition to producing gels which are not pourable, this practice may also produce gels which are so tight that the water is squeezed out leaving the explosive insensitive.

An explosive composition can be gelled with small amounts of gelling agents by heating during the mixing stage in an attempt to enhance cross-linking of the gel prior to storage. Normally, heat alone will not complete all of the cross-linking available from the conventional gelling agents present in the formulation. Thus, additional crosslinking takes place during storage with the possibility of ingredient separation due to the incomplete initial gelation.

ADVANTAGES OF THE INVENTION l have discovered explosive compositions which can be made to have any desired degree of gelation simply by controlling their final pH. A gelled explosive composition can be made which is tight enough so that the components of the explosive do not segregate on storage, yet is pourable and has good bag release, and the preferred compositions do not gel significantly further on storage. Moreover, gels can be formed at a pH as low as 5 in the compositions of this invention using as gelling agents those gums which would previously gel only at at higher pH.

But the most remarkable property of the compositions of this invention is the ease with which the degree of gelation can be controlled. While prior art gels, once formed, cannot be easily ungelled, the gels of this invention can be repeatedly made tighter or weaker by successive adjustments of their pH.

COMPOSITIONS OF THIS INVENTION The explosive compositions of this invention comprise a gelling agent, boric acid, an aqueous medium, an oxidizer, and a fuel component. An explosive composition may be formed from 1 part by weight (pbw) oxidizer, about 0.14 to 0.43 pbw water, about 0.007 to 0.4 parts per part ofwater ofa two-component mixture about 20 to 80 percent of which is a boric acid and about 20 to 80 percent of which is a gelling agent and a sufficient amount of a fuel component to give an oxygen balance between about +10 and 30. The explosive composition also preferably contains about 0.7 to 2.5 pbw of a sensitizer.

Boric acid is the cross-linking agent and is the component of the compositions of this invention which gives them their unusual properties. As smaller and smaller amounts of boric acid are used, the gel becomes thinner and thinner; the full range of gelation from a very thin to a tight gel may be obtained if the amount of boric acid used is equal to at least about 25 percent of the amount of gelling agent used. Excessive amounts of boric acid do not appear to be harmful, but merely unnecessary.

The boric acid is preferably obtained directly from boric acid, B(OH) but may also be obtained from boron compounds which can be substantially dissociated into boric acid. Such compounds include borax, metaboric acid and the metaborates, alkyl boric acids such as butylboric acid, aromatic boric acids such as phenyl boric acid, sodium tetramethoxyborate (borine), boron halides such as boron trichloride and boron tribromide, and boron sulphide.

The gelling agent is a substance, usually polymeric, which is capable of being cross-linked in water to form a gel which is stable in the presence of the oxidizer. The gelling agent is preferably a polysaccharide, preferably a galactomannan such as locust bean gum or guar gum, but may also be a gelling agent such as a biopolymer. Guar gum is usually preferred because of its availability.

The oxidizer is the source of oxygen during the explosion and is preferably ammonium nitrate. However, other inorganic oxidizer salts such as sodium nitrate, calcium nitrate, magnesium nitrate, potassium nitrate, lithium nitrate, ammonium chlorate, potassium chlorate, sodium chlorate, ammonium perchlorate, potassium perchlorate, or sodium perchlorate may also be used.

The fuel component is a substance which consumes oxygen during the explosion. This definition would include the components which function as a gelling agent as well as many components which function as sensitizers. In addition, materials may be added primarily for the purpose of consuming oxygen such as sulfur, coal, bagasse, fuel oil, parafiin oil, etc.; sulfur is preferred. Liquid fuels such as ethylene glycol, formamide, or glycerine may also be used either to reduce the amount of water or to promote low-temperature pourability.

A sensitizer is a substance which increases the sensitivity of a composition and includes explosive compounds, air-entrapping materials, and finely divided metals. Explosive sensitizers include, for example, nitroglycerin, TNT, DNT, tetryl, RDX, PETN, nitromethane, and amine nitrates such as methyl amine nitrate and ethylene diamine dinitrate. Examples of airentrapping materials include expanded perlite and glass, ureaformaldehyde and phenol formaldehyde micro-spheres. Aluminum and magnesium, for example, may be used as finely divided metal sensitizers. A combination of an air-entrapping material and an explosive sensitizer is preferred because it produces the greatest sensitivity.

Other compounds may also be included in the compositions for various purposes, such as surfactants to help promote the gelling process.

METHOD OF CONTROL The present invention contemplates control over the degree of gelation of gelling agent, water, and boric acid compositions by adjusting the pH of the composition. Essentially, one first prepares a mixture containing at least the boric acid, the gelling agent, and the aqueous medium, although the mixture may also contain other components of the composition. The pH is adjusted to the final pH with a base or an acid, for example, ammonium hydroxide or acetic acid, and any remaining components are mixed in. Alternatively, the boric acid may be added after the pH is adjusted to the final pH, but it is preferably to add the boric acid before the final pH adjustment so that one may observe the degree of gelation as one adjusts the pH.

The final pH determines the properties of a given composition. The higher the final pH, the tighter will be the gel, and the lower the final pH, the more fluid will be the gel; also, the gel is more adhesive at lower pH levels and, therefore, will give better release from a plastic bag at higher pH levels. It is preferable to start at a low pH, say, at most about 4.5, and to raise it to the final pH rather than starting at a high pH and lowering it to the final pH because it is much easier to disperse any insoluble materials in a thin gel than in a tight gel.

Generally, a final pH above about 7 is undesirable because the gel is so tight that water squeezes out. the components COMMENTS FOR TABLES 1 AND ll separate, and it is not pourable and has no water-resistance; Q gel however, it is still detonable. Also, a final pH less than about 2 C Thim nonwhesive gel is generally undesirable because a thickened mass results 5 D Thin, pourable gel rather than a gel; it has no water-resistance either but is still 5 e my detonable. For best results, the final pH should be between 4.5 g zx szgig gel system and 7, although these limits will vary with the composition H Tight gel not pourablc used; a pH between 5.0 and 6 is the preferred range. Provided y f the 1f the composition contains a liquid which 15 not easily 10 2 g zzgh i shzzfi Culncundenhc gelled such as some olly fuels, for example, fuel oil, paraffin lmdemarkX058? oils, and particularly nitroparaffins such as nitromethane, the 3. Sold by General Mills, Inc. under the trademark best procedure is to prepare a mixture containing at least the boric acid, the gelling agent, the aqueous medium, and the 2 23831?" liquid not easily gelled. The pH is lowered to about 1.5 to 4.4, 5. An anionic heteropolysaccharide produced by the and the mixture is blended well and preferably heated. The pH fermentalion Ufa Carbohydrate y bacterium is then adjusted to the final pH. fic n 'fi s: 22 ge Generally, heating during mixing is desirable as it decreases J "adcmark the time necessary to form a gel; 100 to 180 F. is a suitable Polyhall M-295" range but 140 to 150 F. is preferred If explosive components g g fqz' xgi zg g mszg'ge anal sis are used which are heat-sensitive, the composition should L abcm 335 percent boric acid t, either be heated and cooled before the explosive components percent guar gum, about 22.9 percent water, are added 01' Should not be heated, about 6.7 percent polyacrylamide, and about Ll It is also preferable to add any large, solid materials such as 25 pmbab'y "glycmde prills after the final pH adjustment since the gel has formed by then and will prevent their segregation. The compositions A to R of Tables 1 and 11 were prepared If a boron compound which dissociates into boric acid by mixing the ammonium nitrate and ethylene dlamlhe under the conditions of this invention is used, the boron comdihhrate Solutions, 'f to to i f P pound should be added to the gelling agent under conditions Posltioh H heauhg was h lrf mhlhg Into the which prevent its reaction with the gelling agent prior to dis- 50mm) 3 P of olhel: l The P of the sociation. Some boron compounds such as the metaborates resulting h h adjustefj wlth acetic acld to ahou} dissociate rapidly enough that the conditions of reaction are theh'l'alseld W1th afhmohlum hydroxlde over f e-" sufficient for their use and no special conditions are necessary. Penod h Shmhg the gel formed p h h was Others such as borax and the biborates require time to dis- Prepared the Same mahher except the he was sociate and should be acidified prior to being mixed with the added after the final PH adlhstmehte eompesmohs were gelling agent. In addition, a composition using borax may tend stored at tempemhh'e venous the to vary in pH with time and require adjustments to keep the test? were tefmlnaiefl at h last reading. The ammon um and PH below 7 sodium salts of boric acid were prepared by neutralizing a EXAMPLES 40 saturated solution of boric acid with ammonium and sodium hydroxides to a pH of 10 to 1 1, respectively, and evaporating Tables I and 11 below show the types of gelation which to dryness; these salts apparently did not immediately revert to resulted when various compositions were prepared and stored: boric acid in solution (compositions O and P).

TABLE I Composition, percent; A B C D E F G H I J 6 Ammonium nitrate solution 77.05 77.05 77. 05 77.05 77. 05 77.05 77.05 77.05 77.05 77. 05 Ethylene diamine dinitrate s01uti0n. 21.25 21.25 21.25 21.25 21.25 21.25 21.25 21.25 21.25 21.25 Boric acid 0.78 0.71 0. 69 0.69

Ammonium biborate (NH4HB4O7.3H2O)..-. Borax (NfizBiO'iJUHzO) a a Acidificd borax Non-ionic Guar gum L... Modified Guar gum... Polysaccharide Bio-polymer Polyacrylamide Final pH TAB LE II Composition, percent K Ammonium nitrate solution"... 50% Ethylene diamine dinitratc solutiolL. Boric acid Ammonium salt of boric acid Sodium salt of boric acid Sodium metaborate (NazBzO4.8HzO) Boric Acid-Gum-Amide-Ester Mixture 7 Noni0nlc Guar gum Modified Guar gum. Locust Bean gum Polysaccharide Polyacrylamide Final pH Freshha.

7 days M N O P Q R S As to the compositions of this invention (F to S), the rise in pH produced a corresponding increase in the degree of gelation. As to composition E, once a gel had formed, a further increase in pH had no noticeable effect. Table I shows, inter Composition L was prepared by mixing the nitrates, dinitrate, and the water, heating to 160 F and adjusting the pH to 4.0 with acetic acid. The air-entrapping spheres, sulfur, gelling mixture, and boric acid were blended and the heated alia, that the preferred composition H withstood 120 days of 5 nitrate solution was added incrementally while the temperastorage without further gelation occurring, while prior art ture was maintained at 145 F. The surfactant was added and composition E formed a tight gel within an hour. Compositi the pH adjusted to 4.5 to 5.0 with sodium hydroxide solution. E contrasts markedly with composition P where the borax was The nllfemethane and ethylene g y Wer e mixed and the dissolved in water and acidified with nitric acid to a pH of P was adjusted to the hhalPH whh sofhum hydroxlde about 1.0 to dissociate it into boric acid before it was added to composltlon M was P p by mlxlhg the Sodium and the gelling agent. Although the non-preferred composltlons of monium h h Water at 150 The P was l T this invention (1 and J) did not exhibit extended storage sta- 3 m 4 f e l and 9 and hon; acld bility, their degree of gelation was nevertheless pH sensitive. were mlxed fh h: The epp h p Sulfur Another composition identical to composition R was and ethylene dlamlne dinitrate were mlxed 1n and the pH adprepared in the same manner as composition S. The pH of this lhsted to 4 sodium hydroxide- The ethylehe glycol and composition was then successively adjusted up and down with hmomefhane fvefe added nd the final pH ad ustment was acetic acid and ammonium hydroxide. The following degrees made Sodlum q'P of gelation were observed at successive pH values: f composmons were poumble' and most of composltlons (H, l, and K, for example) are pourable at low temperatures (20 to 30 F.); all the compositions had an oxpH Degree of Gelatlon ygen balance between +10 and 30. The composltlons were 3 9 TH k d placed in 3 inch diameter plastic cartridges and were L we mass detonated with a 3 inch X 6 inch 75 percent gelatin dynamite.

. oose gel. very tacky I 5.3 Excellent pourability, tacky (poor release) what 15 clalrhed 1S: h 5.2 Excellent pourability, good release 1. An exploslve composition comprlsing boric acid, a gelling f P h agent, an aqueous medium, an oxidizer, and a fuel component. slightly Wmammy lease 2. A composition according to claim 1 which contains a sen- 6.6 Tlght gel, not pourable, breaks apart easlly 6.0 Good pourability. excellent release sltlzer' 4 5.25 Excellent pourability, tacky 3. The composition of dam 1 wherein said boric acid lS ob- 9 s y tacky tained by acidifying borax. Tl'mkened 4. The composition of claim 1 wherein said gelling agent is a 6.9 Tight gel, not pourable. breaks apart easlly, water squeezed polysaccharlde. I 4 so Good pourability, excellent release 5. The composltlon of claim 4 wherein said polysaccharlde 4.75 Loose "'3' h is a galactomannan. "lease 6. The composition of claim 5 wherein said galactomannan 3.5 Thlckened mass 5.75 Excellent puurahility, good release ls guar 7. An ex loslve com osltlon com rlsln l bw oxldlzer,

P P P 8 P about 0.14 to about 0.43 pbw water, about 0.007 to about 0.4 Table lll below shows additional explosive compositions parts per part of water of a two-component mixture about 20 prepared according to this invention. to percent of which is boric acid and about 20 to 80 per- Composition, percent A B C D E F G H I I K L M Ammonium nitrate 41. 5 36. 2 31. 2 40. 7 39. 2 34. 2 .2 47. 05 43. 3 42. J Sodium nitrate 18.0 11.0 11.0 16. 0 11.0 11,0 .0 10.0 10.0 Calcium nitrate 5. 0 5. 0 5. 0 5. 0 .0 Gelling mixture 2 1. 1 0.9 0. 9 0. 9 0. 0 0. 9 .9 0. 35 0.6 1. 1 Bolic acid v 0. 5 0. 6 Water 14. 0 20.0 20.0 18.0 20. 0 20. 0 .0 20. 0 20. 0 20. 0 Ethylene glycol 7. 5 7. 5 7.5 7, 5 .5 10.0 5. 0 b. 0 Surfactant 3 0 4 0. 4 0. 4 0. 4 0. 4 0. 4 .4 0. 6 0. 5 l. 0 Sulfur 3.0 3.0 2.0 3. 0 3. 0 .0 3. O 3. (J 3.0

Aluminum. Air'entrapping spheres 2.0 3 .0 3.0 2.0 2.0 Ethylene diarnine dinitrtc. 5. 10.0 5. 0 5. 0 Nitromethane 0 15.0 10. 0 10.0

Nitrostarch T .N.T Final pH nt 5.55 5.8 5.0 5. 5.7 6.1 5. 75 5.85 Dens1 ty,g./cc. 1.47 1.46 1.44 1.40 1. 26 1. 28 nt 1.1 1. 22 1.25 1. '20 1. 20 eloclty, i.p.s 16,200 12,195 11,900 17, 090 16,340 16,025 17,045 14,235 17.005 17.360 17.360 17.010 1 670 nt=Not tested.

1 Phenol formaldehyde in I), E, F, G, I, and J; glass in H, K, L, and M. 9 41.7% bone acid, 49.2% guar gum, 9.2% polyacrylamide in A to K; 50-50 mixture of.laguar and Jaguar DE," non-ionic guar gums sold by Stein. Hall 8; Co., Inc. in L; 50% boric acid and 50% Jaguar 100 in M.

3 Polyoxyethylene alkyl amine sold by Atlas Chemical Industries, Inc. under the trademark (ll-3780A.

In table "I, compositions A to K were prepared by mixing the water, surfactant, and the nitrates and dinitrate at to F. The pH was adjusted to 2 to 3 and the nitrostarch and TNT were added where used; after stirring the aluminum was added (composition G). A pre-mix containing the resin spheres, sulfur, and the gelling mixture was prepared and added with stirring. When the compositions began to thicken, the pH was adjusted with acetic acid to 3.5 to 4.5, and the ethylene glycol and nitromethane were added and stirred in for 1 minute where used. The pH was then adjusted with ammonium hydroxide to the final pH which instantly resulted in the formation of the gel. Whole ammonium nitrate prills were then stirred in, 15 percent (this percentage is included in the figure given in Table III for ammonium nitrate) in cases B and C; 10 percent in case E; and 5 percent in cases H, J, and K.

cent of which is a gelling agent, and a sufficient amount of a fuel component to give an oxygen balance between about +10 and -30.

8. The composition of claim 7 wherein said boric acid is obtained by acidifying borax.

9. A composition according to claim 7 wherein about 0.007 to about 2.5 pbw of a sensitizer is present.

10. A composition according to claim 9 wherein said sensitizer is a combination of an air-entrapping material and an explosive.

11. The composition of claim 10 wherein said air-entrapping material is phenol formaldehyde or glass microspheres.

12. The composition of claim 7 wherein said gelling agent comprises a polysaccharide.

13. The composition of claim 12 wherein polysaccharide is a galactomannan.

14. The composition of claim 12 wherein said galactomannan is guar gum.

15. A method of controlling the degree of gelation of an explosive composition comprised of boric acid, a gelling agent, and water, comprising raising the pH of said composition to increase the degree of gelation and lowering the pH to decrease the degree of gelation.

16. The method of claim 15 wherein said pH is adjusted to about 4.5 to 7.

17. The method of claim 16 wherein said composition contains an oxidizer and a fuel component and is detonable.

18. The method of claim 17 wherein said gelling agent comprises a polysaccharide.

19. The method of claim 18 wherein said polysaccharide is a glactomannan.

20. The method of claim 19 wherein said galactomannan is guar gum.

21. The method of claim 17 wherein the pH is adjusted by lowering it to below about 4.5 and then raising it until a gel of the desired consistency is obtained.

said

22. The method of claim 17 wherein said composition is heated while being gelled.

23. The method of claim 22 wherein said composition is heated to to F.

24. A method of controlling the degree of gelation of an .explosive composition which comprises boric acid, a gelling agent, an aqueous medium, an oxidizer, a fuel component, and a liquid not easily gelledcomprising preparing a mixture which comprises boric acid, a gelling agent, an aqueous medium, an oxidizer, a fuel component, and said liquid, adjusting the pH of said mixture to between 1.5 and 4.4, blending said mixture well, and adjusting the pH of said mixture to between 4.5 and 7.

25. The method of claim 24 wherein said liquid not easily gelled is a nitroparaffin.

26. The method of claim 25 wherein said nitroparaffin is nitromethane.

27. A method of controlling the degree of gelation of the composition of claim 6 comprising adjusting the pH of said composition.

(g 12 9 UNH'HE sTfiTE TE? FEQE C Patent No. 1 3 1 Dated f p 1972 Inventor(s) Donald W. Edwards It is certified phat error appears in the abpve-identif1edpatent I and that said Letters Patent are hereby corrected as shown below:

Column 2, line 64, "preferably" should read -{preferable Column 4, under section COMMENTS FOR TABLES I AND II, Item 2',

"trademark "X0589""should read trademark Jaguar EX-JB Column 4, under section COMMENTS FOR TABLES I AND II, Item 4, "705D--AA" should read "705D-A" Column 4, line 41, l0 to ll should read l0 and 11 The table bridging Columns 5 and 6, i at approximately line 41 should be labeled TABLE III d In said table above (TABLE III) bridging Columns 5 and 6, at approximately line 42 the column headings "H I I K" should read H I J Kand so on.

In said table above (TABLE III) bridging Columns 5 and 6, under table heading Composition, percent, Ethylene diamine dinitrte' should read Ethylene diamine dinitrate Signed and sealed this 5th day of December 1972.

(SEAL) Attest:

EDWARDMQFLETQHERJRQ 7 ROBERT GOTTSCHALK Attesting Officer Commissioner of Patents 33 3 UNITED STATES PATENT omen I CERTIFICATE OF CORRECTION Patent; N0. Datgd 4,

Inventor(s) Donald W. Edwards It is certified that verror 8PPears in the ebpv e- -identified'patent and that said Letters Patent are hereby corrected as shown'below:

Column 2, line 64,"preferably" should read pref erable Column 4, under section COMMENTS FOR TABLES I AND II Item 2, "trademark "XO589"" should read trademark Jaguar EX-JB Column 4, under section COMMENTS FOR TABLES "I AND II, Item 4, "705D-AA" should read "705D-A" Column 4, line 41, "l0 to 11" should read l0 and 11 The table bridging Columns 5 and 6 at approximately line 41' should be labeled TABLE III In said table above (TABLE III) bridgingColumns 5 and 6, at approximately line 42 the column headings "H I I I 'K" should read H I J K--and so on.

In said table above (TABLE III) bridging Columns 5 and 6, under table heading Composition, percent, "Ethylen'e diamine dinitrte" should read Ethylene diamine dinitrate Signed andsealed this 5th day of Deoember 1972. Q

(SEAL) Attest:

LEDWARDMJLETCHEBJR. I ROBERT GOTTSCHALK J Attestlng Officer- Commissioner of Patents

Claims (26)

1. 2. A composition according to claim 1 which contains a sensitizer.
2. 3. The composition of claim 1 wherein said boric acid is obtained by acidifying borax.
3. 4. The composition of claim 1 wherein said gelling agent is a polysaccharide.
4. 5. The composition of claim 4 wherein said polysaccharide is a galactomannan.
5. 6. The composition of claim 5 wherein said galactomannan is guar gum.
6. 7. An explosive composition comprising 1 pbw oxidizer, about 0.14 to about 0.43 pbw water, about 0.007 to about 0.4 parts per part of water of a two-component mixture about 20 to 80 percent of which is boric acid and about 20 to 80 percent of which is a gelling agent, and a sufficient amount of a fuel component to give an oxygen balance between about +10 and -30.
7. 8. The composition of claim 7 wherein said boric acid is obtained by acidifying borax.
8. 9. A composition according to claim 7 wherein about 0.007 to about 2.5 pbw of a sensitizer is present.
9. 10. A composition according to claim 9 wherein said sensitizer is a combination of an air-entrapping material and an explosive.
10. 11. The composition of claim 10 wherein said air-entrapping material is phenol formaldehyde or glass micro-spheres.
11. 12. The composition of claim 7 wherein said gelling agent comprises a polysaccharide.
12. 13. The composition of claim 12 wherein said polysaccharide is a galactomannan.
13. 14. The composition of claim 12 wherein said galactomannan is guar gum.
14. 15. A method of controlling the degree of gelation of an explosive composition comprised of boric acid, a gelling agent, and water, comprising raising the pH of said composition to increase the degree of gelation and lowering the pH to decrease the degree of gelation.
15. 16. The method of claim 15 wherein said pH is adjusted to about 4.5 to 7.
16. 17. The method of claim 16 wherein said composition contains an oxidizer and a fuel component and is detonable.
17. 18. The method of claim 17 wherein said gelling agent comprises a polysaccharide.
18. 19. The method of claim 18 wherein said polysaccharide is a glactomannan.
19. 20. The method of claim 19 wherein said galactomannan is guar gum.
20. 21. The method of claim 17 wherein the pH is adjusted by lowering it to below about 4.5 and then raising it until a gel of the desired consistency is obtained.
21. 22. The method of claim 17 wherein said composition is heated while being gelled.
22. 23. The method of claim 22 wherein said composition is heated to 100* to 180* F.
23. 24. A method of controlling the degree of gelation of an explosive composition which comprises boric acid, a gelling agent, an aqueous medium, an oxidizer, a fuel component, and a liquid not easily gelled comprising preparing a mixture which comprises boric acid, a gelling agent, an aqueous medium, an oxidizer, a fuel component, and said liquid, adjusting the pH of said mixture to between 1.5 and 4.4, blending said mixture well, and adjusting the pH of said mixture to between 4.5 and 7.
24. 25. The method of claim 24 wherein said liquid not easily gelled is a nitroparaffin.
25. 26. The method of claim 25 wherein said nitroparaffin is nitromethane.
26. 27. A method of controlling the degree of gelation of the composition of claim 6 comprising adjusting the pH of said composition.