US3337380A - Explosive slurries from saturated ammonium nitrate solutions and process for preparing the same - Google Patents

Description

United States Patent EXPLOSIVE SLURRIES FROM SATURATED AM- MONIUM NITRATE SOLUTIONS AND PROCESS FOR PREPARING THE SAME George L. Griflith, Coopersburg, Pa., assignor to Trojan Powder Company, Allentown, Pa., a corporation of New York No Drawing. Filed Oct. 2, 1964, Ser. No. 401,247

15 Claims. (Cl. 149-38) This invention relates to aqueous explosive slurries, and more particularly, to explosive slurries based on an inorganic nitrate and sensitized with nitrostarch as the explosive sensitizer.

Explosive mixtures containing relatively large amounts of Water have recently become of considerable interest in the explosive art, and to a considerable extent in recent years have displaced dry mixtures. They have greater versatility than dry mixtures, because they can be used under conditions where water cannot be excluded, such as in wet bore holes, and the flowable slurries also may be brought more easily to certain types of sites, such as bore holes and rock crevices. The water content of such slurries is always more than that which is absorbed by the components of the mixture, and in addition is sufficient to act as a suspending agent for the mixture. Such slurries are distinguishable from gelled explosives in that they are flowable at room temperature, even when they contain a thickening agent to increase the consistency slightly. The water content of flowable slurries in most cases ranges from about to more than 50%, depending upon the materials present in the mixture, and upon the consistency desired.

A slurry having a reasonably stiff consistency, but which is still freely flowable at room temperature, containing as little as 10% water, may be preferred for use in bulk in wet bore holes where the composition may be diluted with water already present. Thickening or gelatinizing agents are employed when thick slurries are desired, containing high proportions of water. A slurry which can be poured may be desired for use in bulk, or in dry bore holes, and such a slurry is easily obtained by using a rather large proportion of water, for example 20 to 50%, without a thickening or gelatinizing agent.

Water is known to have a desensitizing effect upon inorganic nitrate explosives, and aqueous ammonium nitrate slurries are considerably less sensitive than the dry ammonium nitrate formations. This is not necessarily a disadvantage, since an explosive sensitizer can be incorported in such slurries. Nitrostarch sensitized ammonium nitrate slurries have a greatly increased sensitivity, for example.

In accordance with the invention, aqueous inorganic nitrate slurries sensitized with nitrostarch are provided having a greatly increased sensitivity and density, due to the process by which they are prepared. The aqueous explosive slurries of the invention are based on an inorganic nitrate oxidizer and sensitized with nitrostarch, a porous particulate explosive sensitizer, as the principal explosive ingredients. The slurries in accordance with the invention unexpectedly are superior in nearly all respects to similar slurries made simply by blending particulate inorganic nitrate, nitrostarch and water to produce a slurry of identical composition, showing that the process by which these slurries are prepared is critical to the increased sensitivity and other desirable properties of the slurries of the invention. The explosive slurries of the invention have high rates of detonation, and great explosive power. They are impact resistant, and yet far more sensitive to detonating agents than are the corresponding inorganic-based slurries prepared by other procedures. These improvements are in large measure due to the porous condition of the nitrostarch particles, which can absorb inorganic nitrate solutions and therefore come in intimate contact with the nitrate.

The explosive slurries of the invention' are prepared starting from substantially saturated aqueous slurries of ammonium nitrate, containing undissolved ammonium nitrate only in the form of particles of ammonium nitrate precipitated from a saturated solution of ammonium nitrate, containing at least ammonium nitrate, and preferably 83% ammonium nitrate or more. Such aqueous solutions should be substantially free from undissolved ammonium nitrate, as initially prepared, before precipitation of ammonium nitrate therein.

It will be seen from the solubility tables of ammonium nitrate in water that saturated aqeuous solutions of such concentrations can be obtained only at temperatures of 210 F. and higher. At lower temperatures, saturated aqeuous solutions of ammonium nitrate are not capable of dissolving at least 80% of ammonium nitrate. The solubility tables for ammonium nitrate in water are obtained at atomspheric pressure. Even higher concentrations of ammonium nitrate can be obtained by heating ammonium nitrate and water at super-atmospheric pressures, to maintain water in the liquid phase at temperatures considerably above the boiling point of the solution. In accordance with the invention, it is preferred that the saturated solution of ammonium nitrate contain as much ammonium nitrate above 80% as possible.

Accordingly, it is usually desirable to heat particulate ammonium nitrate, such as prills, granules or powder, with the minimum amount of water, and with agitation, to a temperature in excess of 210 F., and preferably within the range from about 225 to about 250 F., continuing the heating until all of the ammonium nitrate has dissolved. This saturated solution, substantially free from undissolved ammonium nitrate, is then cooled to a temperature at which it is safe to add the other ingredients of the explosive slurry. During cooling, the saturated solution is constantly agitated, so as to prevent setting. Rapid agitation is desirable, since the more rapid the agitation, the more finely divided the particle size of the ammonium nitrate that will precipitate from the saturated solution during cooling. The solution usually should be cooled to a temperature below about 125 F., and preferably below about F., at which time the other ingredients of the explosive are added. Stirring is continued throughout.

The explosive slurries prepared in this way will contain water, in excess of 10%, enough to act as a suspending medium for the solid ingredients. If more water is desired, additional water can be added after the mixture has been cooled to below about P. On the other hand, if the mixture contains too much water, even though the minimum required to form a saturated solution of the ammonium nitrate has been employed initially, water can be removed by evaporation, holding the mixture at an elevated temperature, preferably with application of vacuum or suction, such as by use of a water pump, to remove water vapor and concentrate the slurry. Alternatively, a thickening or gelatinizing agent can be added to take up the excess water.

Usually, 10% water is suflicient to form a slurry, but

Patented Aug. 22, 1967' more than this may be required to make the slurry freely fiowable at room temperautre. The practical upper limit of water is set by excessive dilution and dissipation of the explosive power, taking into account any loss of water by volatilization and absorption into the ground before the slurry is used. In most cases, the preferred range of water content will be from about 10% to about 40%, although in some cases as much as 50% might be used. Even more than 50% can be used when a thickening or gelatinizing agent is incorporated, but obviously it is uneconomic to employ more water than is necessary, and then increase the viscosity by the addition of a further costly ingredient, when the same consistency can be obtained merely by using less water. The slurries obtained in accordance with the process of the invention will normally not contain excess water if a minimum of water is used in the preparation initially of the saturated nitrate solution.

Any inorganic nitrate can be employed as the oxidizer in the slurries of the invention. Ammonium nitrate is the nitrate normally used. However, any inorganic nitrate can be employed in admixture with the ammonium nitrate. Nitrates of the alkali and alkaline earth metals, such as sodium nitrate, potassium nitrate, calcium nitrate, strontium nitrate, and barium nitrate, are exemplary additional inorganic nitrates. Mixtures of ammonium nitrate with alkali and/ or alkaline earth metal nitrates in proportions within the range from about 25 to about 95% of ammonium nitrate, and from about 75 to about 5% of the other nitrates, are preferred in many instances because of their high explosive power. Compositions based on ammonium nitrate as the sole inorganic nitrate are also preferred because of their high power.

The supplemental inorganic nitrate may be fine, coarse, or a blend of fine and coarse materials. Mill and prill inorganic nitrates are quite satisfactory. The type of particle employed as a starting material for the supplemental nitrates is immaterial whenever these are dissolved with the ammonium nitrate to form a saturated solution initially. However, the supplemental inorganic nitrate can also be reserved, and added to the slurry with the other ingredients, after the saturated ammonium nitrate solution has been cooled to precipitate ammonium nitrate.

The explosive slurries of the invention contain nitrostarch, a porous particulate explosive sensitizer, in addition to the inorganic nitrate oxidizer. Nitrostarch is the preferred explosive sensitizer in the aqueous slurries of the invention, because of its higher rate of detonation, greater power and more sensitivity to detonating agents than other explosive sensitizers in the same environment. Also, such slurries freeze more slowly, and when frozen are not as difficult to work.

It is believed that the nitrostarch is effective in the slurries of the invention because of the porous character of the particles. Hence, any explosive sensitizer capable of being formed in porous particles can be employed.

Nonporous particulate explosive sensitizers also can be used, in combinations with nitrostarch, but the major proportion, i.e., at leat 50%, and preferably at least 75%, of the total explosive sensitizer will be nitrostarch. Exemplary of these are dinitrotoluene, trinitrotoluene, pentaerythritol tetranitrate, pentolite (an equal parts by weight mixture of pentaerythritol tetranitrate and trinitrotoluene) cyclonite (RDX), cyclotrimethylene trinitroamine, nitrocellulose, Composition B (a mixture of up to 60% RDX, up to 40% TNT, and 1 to 4% wax), cyclotol (Composition B without the wax), tetryl, smokeless powder and carbine ball powder.

The relative proportions of inorganic nitrate and total explosive sensitizer will depend upon the sensitivity and explosive effect desired, and are not critical. These in turn are dependent upon the particular nitrate or nitrates used. For optimum effect, the inorganic nitrate is used in an amount within the range from about 50 to about 75%, and the total explosive sensitizer in an amount within the range from about 10 to about 25%. The preferred ratios of nitrate explosive sensitizer are from 5:1 to 2:1. However, from about 35 to about 75% inorganic nitrate, and from about 2 to about 30% total explosive sensitizer give quite satisfactory results in the slurried explosive mixtures of the invention.

In addition to these materials, which are the essential ingredients, the explosive slurries can include one or more fuels, such as a metal fuel, or a carbonaceous fuel, or both. Illustrative of particulate metals, for example, are aluminum powder, flake aluminum, atomized aluminum, ferrophosphorus, and ferrosilicon. A metal fuel when present will usually comprise about 0.5 to about 30% of the slurry. Useful carbonaceous materials are powdered coal, coal dust, charcoal, bagasse, dextrin, starch, wood meal, flour, bran, pecan meal or similar nutshell meals, and paraifin oils. The carbonaceous fuel, when present, usually comprises from about 0.5 to about 30% of the mixture. Mixtures of such fuels can also be used, in amounts within the range from about 0.5 to about 30%.

An antacid such as zinc oxide can be added, if desired. Small amounts, up to about 5%, are sufficient.

In many cases, an oil can be added to serve not only as a fuel but also to supplement the water as a suspending medium for the solid ingredients. In such cases, the viscosity of the oil is of course a factor to be taken into account. Any oil can be used as a suspending medium. Petroleum-derived hydrocarbon oils are readily available, and are preferred because of their low cost. The viscosity can range from very thin oils, such as 50 SSU at F., to quite heavy oils, ranging up to about 1200 SSU at 100 F. Kerosene, fuel oil, 100 SSU paraffin oil, light straw paraffin oil, SAE 10 to 50 lubricating oils and bydraulic oils are exemplary.

Water is thinner than most of the oils that would be used in this way, and would consequently reduce the consistency of the slurry more than the oil. Less water than oil of the same viscosity, therefore, is required to slurry the mixture, so that a mixture of oil and water may be more advantageous than water alone for this reason, if a slurry of a particular consistency be desired. In all cases, oxygen balance must also be taken into account in determining the proportions of water and oil that should be used. Good proportions for oil-water slurries, using finely divided nitrate oxidizer and explosive sensitizer, taking all of the above factors into consideration, are from 2 to 10% water, and from 10 to 30% oil. Such slurries have a satisfactory fluidity, which can be reduced by addition of an appropriate amount of thickening agent.

The consistency of the slurries of the invention for any given amount of water, or water and oil, can be increased as desired by incorporating a thickening or gelatinizing agent. In this way, it is possible to prepare a thick slurry containing a large proportion of water for use in bulk or dry bore holes. The thickening agent is water-soluble, according to the suspending medium used, and inert to the other ingredients present. Thickening agents for water and for oils are well known materials, and any of those known to the art can be used. The amount of thickening agent will depend on the consistency desired, and will be within the range from 0 up to about 10%.

Well known water-thickening agents that can be employed include sodium carboxymethyl cellulose, methyl cellulose, guar gum, psyllium seed mucilage, and pre-gelatinized starches such as Hydroseal 3B. Noncarbonaceous inorganic oil thickeners include finely divided silica, available under the tradenames Cab-O-Sil and Ludox, and silica aerogels, for example, Santocel Ard and Santocel C, and like inorganic gelling agents, such as alumina, attapulgite and bentonite. Other gelling agents are disclosed in US. Patents Nos. 2,655,476 and 2,711,393.

In no case is an amount of thickener added that would result in a gel that is not fiowable at room temperature. The maximum consistency of the slurries of the invention is a thick, barely pourable mixture, and the consistency can decrease from this maximum to that of a quick flowing liquid, not unlike water itself.

The explosive slurries of the invention will ordinarily be fired with the aid of an initiator or a booster charge, and combinations of the explosive slurry and an initiator or a booster in the same container, or separately packaged as a was determined using the standard tests for determining ballistic pendulum value, sensitivity in a 1 /2 inch pipe, and rate of detonation in a 1 /2 inch pipe. In the sensitivity tests, when the scope of the standard cap has been passed, there were used progressively as more powerful initiators, 3 g. pentaerythritol tetranitrate booster and then 5, 10, 15, 20, 25, 30, 40, 50, 60, 75, 100, 125, 150,

200, and 250 g. and then /2 1b., 1 lb., and 2 lb. cast pentolite boosters.

- EXAMPLE A 498 lbs. of prill ammonium nitrate and 102 lbs. of

water were mixed in a 55 gallon drum. A steam coil was used to heat the mixture, and air was used for agitation. The temperature of the solution when all of the ammonium nitrate had completely dissolved was 234 F. The ammonium nitrate concentration was 83.4%, and water 16.6%.

This saturated solution was charged into a Holoflite processor, constructed on the principle of rotating, hollow, helical flights in a trough to process material with indirect heat exchange while providing adequate agitation. The heat exchange medium is completely isolated from the material being processed in this processor, and the heat is transferred by contact with the surfaces of the hollow flights and the shaft. Since the principle of the conveyor is employed, the particles of material within the mass are subjected to continuous movement by the helices, and are constantly changing location. This causes them to come into frequent and repeated contact with the surface containing the heat exchange agent. The resulting flow, rotating, conveying, interfolding, and the dispersing action give a maximum of heat transfer in a minimum of time, and ensure thorough mixing.

The saturated solution of ammonium nitrate was charged to the Holoflite unit over a period of one hour. Fifteen minutes after the material had been charged into the processor, it began to discharge from the opposite end. The mixture discharged a slurry of very fine ammonium nitrate particles in a saturated ammonium ni trate solution, had a moisture content of 16.19%, at a temperature of 106 F. The discharged material had the consistency of a sludge, with a small amount of liquor dispersed throughout the mixture. The temperature of the discharged water from the flights of .the conveyor was 65 F.

Example 1 The saturated ammonium nitrate liquor in accordance with Example A, after cooling to 106 F., at which time it was in the form of a slurry containing fine needles of precipitated ammonium nitrate, was used as a starting material for the formation of an aqueous ammonium nitrate slurry in accordance with the invention, to the formulation given in the following table. The slurry was formed by blending in the additional solid ingredients in particulate form listed in the table. The solid materials were mixedthoroughly'before-addition to the slurry, with stirring.

For purposes of comparison, a slurry identical in composition was prepared using solid ammonium nitrate prills and water, together with the other ingredients. The solid materials were mixed thoroughly, and then the water was added, forming the slurry designated Control in the table which follows:

TABLE I Example 1, Control,

percent percent N itrostarch (wet) 22. 40 22. 40 Ammonium Nitrate Liquor from Holo- Flite 64.00 Ammonium Nitrate (Monsanto AO-l Prills 53.10 10.00 0.80 1.50 0.50 0.80 10.90

1 Water in Ammonium Nitrate Solution.

The density, ballistic pendulum value, sensitivity in 1 /2" pipe and rate of detonation in 1 /2" pipe were determined for each of these slurries. The following data were taken:

' Examplel Control Density 1. 425 1. 395 Ballistic pendulum value 10.00 9. Sensitivity in 1%" Pipe (Pentolite) (gm.) 20 30 Rate of detonation in 1 Pipe (m./seo.) 4, 810

EXAMPLE B A mixture of 498 lbs. of prilled ammonium nitrate and 102 lbs. of water were mixed in a 55 gallon drum. A steam coil was used to heat the mixture, and air was used to agitate the material during the heating. The temperature of the mix when the ammonium nitrate had completely dissolved was 234 F., and the ammonium nitrate concentration at this temperature was 82.71%, the water 17.29%. This saturated solution was charged into a Holo- Flite processor over aperiod of one hour.

The temperature of the water entering the screw conveyors was 47 F. The discharged material, a slurry of very fine ammonium nitrate particles in a saturated ammonium nitrate solution, had a temperature of 106 F., and a moisture content of 16.36%. The discharged material had the c-onsistency of a sludge.

Example 2 The saturated ammonium nitrate solution of Example B, containing finely divided needles of ammonium nitrate suspended therein, was then used as a starting material for the preparation of a slurry in accordance with the invention, employing nitrostarch as the explosive sensitizer, to the formulation shown in the table below. The solid ingredients were mixed together, and then blended with the ammonium nitrate slurry.

' For purposes of comparison, a slurry identical in composition was prepared, starting with ammonium nitrate prills and water, together with other solid ingredients. All of the solid materials were mixed thoroughly, and

then the water was added. The composition of this slurry is indicated as Control in the following table:

Water in Ammonium Nitrate Solution.

The density, ballistic pendulum value, sensitivity in 1 /2 pipe and rate of detonation in 1 /2" pipe were determined for these slurries. The following data were taken:

Example 2 Control Density 1. 420 1. 370 Ballistic pendulum value 10. 15 10.35 Sensitivity in 1% pipe (Pentolite) (gm.) 30 35 Rate of detonation in 1%" pipe (m./sec.) 4, 898

The data show that the slurry of the invention had a higher density, a considerably better sensitivity, an excellent rate of detonation, and approximately the same ballistic pendlum value, as the Control.

EXAMPLE C A mixture of 102 lbs. of water and 498 lbs. of prilled ammonium nitrate was heated in a 55 gallon drum, using steam coils, with air agitation. The ammonium nitrate had completely dissolved when the temperature reached 214 F. The resulting saturated solution was then passed to a Holo-Flite processor on a 14 pitch, with the discharge end being the high point. The flights of the screw conveyor turned at 3 r.p.m. The moisture content of the saturated solution was 16.36%, and the ammonium nitrate content 83.64%. Temperature of the cooling water was 48 F. The material was charged into the processor at the rate of 720 lbs. per hour. The discharged material, a slurry of very fine ammonium nitrate particles in a saturated ammonium nitrate solution, had a sludge-like consistency, a temperature of 104 F. and a moisture content of 16.19%.

Example 3 The saturated ammonium nitrate solution prepared as described in Example C and containing finely divided dispersed needles of ammonium nitrate was used as a starting material for the preparation of a slurry in accordance with the invention, to the formulation given in the table below. The solid ingredients listed in the formulation were mixed, and then blended with the ammonium nitrate slurry.

A similar slurry was prepared to exactly the same formulation, using dry prill ammonium nitrate and water. The solid materials were mixed thoroughly, and then the water was added. This formulation is labelled Control in the table.

Example 3, Control, percent percent Nitrostarch (wet) 22.40 22. 40 Ammonium Nitrate Liquor from Holo Flite 64.00 Ammonium Nitrate (Monsanto AC-l Prills 53. 10 Sodium Nitrate, mill. 10. 00 10. 00 Zinc Oxide 0.80 0.80 Coal (ADM F-l Bituminous). 1.50 1. 50 Oil No. 5 0.50 0.50 Guar gum 0.80 0 80 Water 1 (10.90) 10.90

1 Water in Ammonium Nitrate Solution.

Each of these slurries was subjected to tests to determine density, ballistic pendulum value, sensitivity in 1 /2" pipe and rate of detonation in 1 /2 pipe. The following data were taken:

Example 3 Control Density 1. 440 1. 410 Ballistic pendulum value 10. 10 10. 35 Sensitivity in 1%" pipe (Pentolite) (g 10 30 Rate of detonation in 1% pipe (m./see.) 4, 987

It is evident from the data that the slurry of the invention had a higher density, a greater sensitivity, and good rate of detonation and ballistic pendulum values.

Example 4 TABLE IV Example 4, Control,

percent percent Nitrostarch (wet) 22.40 22. 40 Amonium Nitrate Liquor from Holo-Flite. 74.00 Ammonium Nitrate (Monsanto AC-l Prills) 61.40

1 Water in Ammonium Nitrate Solution.

These slurries were subjected to tests to determine the density, ballistic pendulum value, sensitivity in 1 /2 pipe and rate of detonation in 1 /2 pipe. The following data were taken:

The slurry of the invention had an appreciably higher density, a higher ballistic pendulum value, increased sensitivity and an excellent rate of detonation.

9 Example An ammonium nitrate slurry was prepared in accordance with Example C, containing 83% ammonium nitrate, and an explosive slurry using this ammonium nitrate slurry, then prepared to the following formulation. The dry ingredients of the formulation were thoroughly mixed, and then added to the ammonium nitrate slurry.

The above formulation was loaded into a bore hole 8 feet deep and 2 inches in diameter, drilled in solid limestone, and shot with a /3 lb. Pentolite booster. Rock breakage was good.

The following is claimed:

1. An aqueous explosive slurry consisting essentially of from about 35 to about 95% by weight of an inorganic nitrate oxidizer of which from 35 to 100% is ammonium nitrate, from about 2 to about 30% by weight of porous particulate nitrostarch, and an amount of water within the range of about to about 50% by weight of the composition, sufiicient to act as a suspending medium for the solid ingredients, substantially all undissolved ammonium nitrate being in the form of crystals prepared by precipitation from a saturated solution of ammonium nitrate containing at least 80% ammonium nitrate.

2. An aqueous explosive slurry in accordance with claim 1 in which all of the inorganic nitrate oxidizer is ammonium nitrate.

3. An aqueous explosive slurry in accordance with claim 1 in which the inorganic nitrate oxidizer also comprises an inorganic nitrate selected from the group consisting of alkali and alkaline earth metal nitrates.

4. An aqueous exjlosive slurry in accordance with claim 1 including from about 0.5 to about 30% of a fuel.

5. An aqueous explosive slurry in accordance with claim 4 in which the fuel is particulate aluminum.

6. An aqueous explosive slurry in accordance with claim 4 in Which the fuel is a carbonaceous material.

7. An aqueous explosive slurry in accordance with claim 4 in which the fuel is a mixture of particulate aluminum and a carbonaceous material,

8. An aqueous explosive slurry in accordance with claim 1 including a thickening agent in an amount to appreciably increase the viscosity of the slurry.

9. An aqueous explosive slurry in accordance with claim 8 in which the amount of the thickening agent is up to about 10%.

10. An aqueous explosive slurry in accordance with claim 1 which comprises nitrostarch and another explosive sensitizer.

11. An aqueous explosive slurry in accordance with claim 1 comprising an oil in an amount to complement the water as a suspending medium for the solid ingredients.

12. A process for preparing an aqueous explosive slurry which comprises forming a substantially saturated aqueous solution of ammonium nitrate containing at least ammonium nitrate at a temperature above about 210 F., cooling the solution to a temperature below about F. while constantly stirring to form a slurry comprising a saturated solution of ammonium nitrate and finely divided precipitated ammonium nitrate; and blending porous particulate nitrostarch therewith in an amount to form an aqueous explosive slurry consisting essentially of from about 35 to 75% by weight of ammonium nitrate, from about 2 to about 30% by weight of nitrostarch and water.

13. A process in accordance with claim 12 which includes incorporating an inorganic nitrate selected from the group consisting of alkali and alkaline earth metal nitrates with the ammonium nitrate at the time the saturated solution is formed.

14. A process in accordance with claim 12 which includes incorporating an inorganic nitrate selected from the group consisting of alkali and alkaline earth metal nitrates with the explosive sensitizer.

15. A process in accordance with claim 12 which comprises blending another explosive sensitizer therewith in addition to the nitrostarch.

References Cited UNITED STATES PATENTS 3,083,127 3/1963 Grifiith et al 149-38 X 3,216,872 11/1965 Wells l4939 3,222,232 12/1965 Schwoyer 149--38 X 3,238,074 3/1966 Grifiith et al 14938 3,249,476 5/1966 Clay et al 14938 CARL D. QUARFORTH, Primary Examiner. BENJAMIN R. PADGETI, Examiner. S. .I. LECHERT, JR., Assistant Examiner,

Claims (2)

1. AN AQUEOUS EXPLOSIVE SLURRY CONSISTING ESSENTIALLY OF FROM ABOUT 35 TO ABOUT 95% BY WEIGHT OF AN INORGANIC NITRATE OXIDIZER OF WHICH FROM 35 TO 100% IS AMMONIUM NITRATE, FROM ABOUT 2 TO ABOUT 30% BY WEIGHT OF POROUS PARTICULATE NITROSTARCH, AND AN AMOUNT OF WATER WITHIN THE RANGE OF ABOUT 10 TO ABOUT 50% BY WEIGHT OF THE COMPOSITION, SUFFICIENT TO ACT AS A SUSPENDING MEDIUM FOR THE SOLID INGREDIENTS, SUBSTANTIALLY ALL UNDISSOLVED AMMONIUM NITRATE BEING IN THE FORM OF CRYSTALS PREPARED BY PRECIPITATION FROM A SATURATED SOLUTION OF AMMONIUM NITRATE CONTAINING AT LEAST 80% AMMONIUM NITRATE.

12. A PROCESS FOR PREPARING AN AQUEOUS EXPLOSIVE SLURRY WHICH COMPRISES FORMING A SUBSTANTIALLY SATURATED AQUEOUS SOLUTION OF AMMONIUM NITRATE CONTAINING AT LEAST 80% AMMONIUM NITRATE AT A TEMPERATURE ABOVE ABOUT 210*F., COOLING THE SOLUTION TO A TEMPERATURE ABOVE ABOUT 125* F. WHILE CONSTANTLY STIRRING TO FORM A SLURRY COMPRISING A SATURATED SOLUTOIN TO A TEMPERATURE BELOW ABOUT 125* F. WHILE CONSTANTLY STIRRING TO FORM A SLURRY COMPRISING A SATRUATED WOLUTION OF AMMONIUM NITRATE AND FINELY DIVIDED PRECIPIATED AMMONIUM NITRATE; AND BLENDING POROUS PARTICULATE NITROSTARCH THEREWITH IN AN AMOUNT TO FORM AN AQUEOUS EXPLOSIVE SLURRY CONSISTING ESSENTIALLY OF FROM ABOUT 35 TO 75% BY WEIGHT OF AMMONIUM NITRATE, FROM ABOUT 2 TO ABOUT 30% BY WEIGHT OF NITROSTARCH AND WATER.

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