JPS5852956B2 - Hydrous explosive composition and its manufacturing method - Google Patents

Description

[Detailed description of the invention] The present invention relates to hydrous explosive blasting compositions with improved injectability.

More particularly, the present invention relates to hydrous explosive blasting compositions having a continuous liquid phase, which phase has a crystallization point below the intended service temperature, contains an uncrosslinked thickening agent, and a small amount of self-crosslinking viscosity. Contains an aqueous solution of an inorganic oxidizing agent salt or salts containing a thickening agent system in combination with a thickening agent.

This thickening agent system allows the composition to be poured into containers as small as 3 inches (7.62 CrrL) or less in diameter, while at the same time making the composition stable and water resistant.

Additionally, this thickening agent system reduces tackiness and imparts "stringiness" to the composition, so that the composition does not unduly stick to the pack or lose integrity during injection. do not have.

The phrase "as small as 3 inches or less in diameter" as used in paragraphs 5 and 5 means that the composition may be poured into a container as small as at least 3 inches in diameter.

However, with the present invention, it is possible to create an effective blasting composition that can be injected into diameters as small as 1 inch or as little as 4 inches as a practical lower limit.

Explosive agents of the type known as water-containing aqueous or slurry explosive blasting compositions have come into prominent use in recent years.

This type of blasting agent generally comprises a viscous continuous fluid phase through which solid components and gas bubbles are dispersed.

For example, such explosives may contain an aqueous solution of inorganic oxidizing agent salts forming a continuous phase, a solid component dispersed throughout the solution such as an insoluble oxidizing agent salt, or a powdered material such as aluminum, carbide-based materials, sulfur, etc. Fuels; similar nitrogen-containing liquids and benzene with generally good solvent properties for alcohols, glycols, amides and oxidizer salts;
Organic liquid fuels, either miscible or immiscible with water, such as toluene, fuel oil, etc., respectively; can contain thickening agents and crosslinking agents and, if desired, a large number of small, microdispersed gas bubbles or microballoons. It is.

Hydrous blasting agents or compositions are usually thickened and made viscous by the inclusion of water-available thickening agents such as guar gum, starch, wheat flour, and the like.

It is important that the thickening agent maintains homogeneity and integrity, thus preserving the stability of the composition.

The stability of the composition is often obtained and further enhanced by the inclusion of a cross-linking agent, which binds the molecules of the thickening agent and imparts the desired firmness or rigidity to the composition. Forms a chain-like molecular network.

Relatively large amounts of thickening agent are generally used for use in adverse environments such as drilling that contains water or high temperature drilling that can cause deterioration of the thickening agent.

In such cases, the thickening agent is usually crosslinked to increase stability.

One of the major benefits of hydrous blasting compositions is that if they are properly thickened (and preferably cross-linked), they can be used to prevent decomposition of the composition and leaching of soluble oxidizer salts. can be used in the presence of water.

These compositions can be formulated and pumped directly into water-containing boreholes without a protective pack.

Recently, hydrous explosives have been packaged in rod-like form and used as a substitute for dynamite rods.

For example, US Pat. No. 3,878,254 describes compositions suitable for packs, and US Pat. No. 3,783,735 discloses an apparatus for preparing and packaging such compositions in bar form.

These packed slurry explosives are commonly used in boreholes that are too small in diameter to be directly pumped and filled.

However, even when packed, these explosives are usually sufficiently concentrated so that they have good water resistance even if the pack is broken in a water-filled borehole.

Such thickening agents are also important for the overall stability of the explosive.

Usually these packed explosives are highly concentrated and
It is cross-linked and thus in the form of a strong gel.

There is often a desire to have a packed slurry explosive that can be perforated or poured from a pack or container into a container of a desired diameter and shape, and that was the object of the present invention.

This packed explosive agent is conveniently stored and transported in packs of the desired size before being poured into containers or boreholes for use.

Packed slurries suitable for this use are referred to later as "injectable slurries" or "injectable blasting agents."

Pourable slurries must be fluid enough to be poured, but must also be sufficiently thickened and crosslinked to be water resistant and stable.

The viscosity of the composition thus requires compromise in order to balance pourability and water resistance with stability requirements.

In addition to this, hydrous explosives are generally sticky, especially those that flow easily, and thus tend to stick to the inside of the pack when injected, and many such explosives are dispersed apart. The pourable slurry should not have undue stickiness and maintain its integrity when poured from the pack, since some of them tend to stick to the pack and lose their integrity when poured; It is important that the material has sufficient stringiness.

``Stringability'' prevents the slurry from being pulled apart,
It also helps "pull" the slurry out of the pack during injection.

Thus, with respect to hydrous blasting agents in general, the important properties of injectable hydrous blasting agents are consistency with respect to injectability, crosslinking, water resistance, tackiness and stringiness.

The combination of a non-crosslinked thickening agent and a small amount of self-crosslinking thickening agent creates a pourable slurry that is water resistant, stable, and optionally pourable into containers 3 inches in diameter or smaller. “It has been discovered that there is something to offer.

The present invention comprises an explosive composition or blasting agent containing a water-resistant concentrated aqueous inorganic oxidant salt-containing fuel having a continuous liquid phase with a crystallization point below the intended use temperature. and a non-crosslinked thickening agent in combination with a small amount of a self-crosslinking thickening agent; It makes the composition injectable while at the same time making it stable and water resistant.

The compositions of the present invention include inorganic oxidant salts dissolved in an aqueous fluid phase.

The oxidizing agent salts are selected from the group consisting of ammonium, alkali and alkaline earth metal nitrates and perchlorates such as sodium, calcium and ammonium nitrates and perchlorates.

It is necessary that substantially all of the oxidizing agent remain in solution at the intended use temperature of the composition, and therefore eutectic bonding of the salts is usually desirable.

In this way, two or more salts, such as ammonium nitrate (AN) and sodium nitrate (S
A combination of calcium nitrate (CN) and SN is present in solution.

The total amount of salt that can be used in the composition and that will remain in solution at the intended use temperature (generally reduced to at least 5°C) is determined by the total amount of water and the amount and type of miscible organic liquid used, if any. , as well as the particular proportions and combinations of the oxidant salts themselves; generally from about 40 to about 70 weight percent of the total oxidant salts are used in the composition of the invention, based on the total composition.

The examples given below illustrate the amounts and combinations of several typical salts.

The water acts as at least part of the solvent for the oxidant salts, helping to keep the salts completely in solution and providing the composition with sufficient fluidity to allow it to be injected. It can be said to be an essential ingredient.

The amount of water required to completely dissolve the salts in an aqueous solution at the intended use temperature can be readily determined by one skilled in the art, depending on the temperature and the various factors listed above.

Water is usually present in the compositions of the present invention from about 10 to about 40 parts by weight, preferably 20 parts by weight upwind.

It is always desirable, although not essential, to use a water-miscible organic liquid fuel both as a fuel and as an additional solvent for the oxidizer salts.

Since organic liquids act as diluents for water, in addition to their action as fuels, their inclusion generally improves the composition since it can displace some of the water, which in large quantities would be detrimental to energy production. In the case of objects, energy can be increased.

Typical water-miscible organic liquid fuels are well known in the art and include alcohols, glycols, amides, and similar nitrogen-containing liquids.

Several representative liquids are shown in the examples below.

Such liquids are generally used in varying amounts between 0 and 20 weight units.

Although not essential, solid pulverulent fuel components common to the art are typically mixed into the compositions of the present invention.

These ingredients are generally added in amounts necessary or in excess to provide a substantially oxygen balanced composition.

For example, finely divided aluminum particles may be present in amounts up to 40 wt.phi., but are usually present in lower amounts.

They should also be in a finely divided form so as not to unduly interfere with the required flowability or pourability of the composition.

The concentrated system is an important concept of the present invention and consists of a combination of non-crosslinked thickening agents and small amounts of self-crosslinking thickening agents.

This combination allows the composition to be poured into containers 3 inches in diameter or less, while at the same time making it stable and water resistant.

A non-crosslinked thickening agent (1) provides sufficient consistency to contribute significantly to overall stability and water resistance, but because it is not crosslinked, the composition remains pourable.

A suitable thickening agent or combination of non-crosslinked thickening agents can also impart high temperature (60° C.) stability to the composition.

Typical non-crosslinked thickening agents are well known in the art and include wheat flour, starch, polysaccharide polymers such as guar gum, and synthetic polymers such as polyacrylamide or biopolymers.

These thickening agents also serve the essential function of keeping finely dispersed sensitive air bubbles in place and preventing substantial separation of the dispersed powdered ingredients.

The presence of a large amount of uncrosslinked crosslinking agent to perform these functions is essential, and uncrosslinkedness is essential for the composition to remain injectable.

The amount of uncrosslinked thickening agent required depends on the desired physical properties, the nature of the composition as determined by its ingredients, and the type of thickening agent used, but is generally about 0.2 wt. From φ to about 6 weights, preferably from about 1 weight φ to about 3 weights φ are used.

A self-crosslinking thickening agent (generally a gum) is an essential component of the present invention because it is primarily responsible for imparting "stringiness" to the composition, and it is also easily injectable when the composition is in a pack. Reduce stickiness.

A minimal degree of established crosslinking is necessary for adequate bowability and generally good stability, and self-crosslinking gums are used in easily controllable amounts of such crosslinking.

A "self-crosslinking" gum contains its own crosslinking agent that acts when the gum is hydrated in solution.

These gums are known in the art and typically include powdered mixtures of guar gum and crosslinking agents.

Antimony borate and chromate crosslinkers are typically used.

A preferred self-crosslinking gum is Schuffin-Hall (Ste
in-Hal I) "EX-23".

"EX-23" is a guar gum containing antimony crosslinker.

Gum other than the "EX" board can also be used.

General Mills also makes many self-crosslinking gums.

Self-crosslinking thickening agents are generally present in an amount of about 0.1 to about 0.5 parts by weight, preferably about 0.1 to 0.3 parts by weight.

Although there are restrictions on the inclusion of self-crosslinking thickening agents,
It provides a critical amount of crosslinking required, thus reducing the total amount of thickening agent required.

It is extremely difficult to reliably control the degree of crosslinking in hydrous blasting agents by conventional means when the degree of crosslinking must be kept very low in order for the composition to be injected.

Adding the crosslinking agent as a separate component to such concentrated solutions and attempting to limit the degree of crosslinking to very small amounts in order to subsequently make the composition injectable is difficult, if not practically impossible.

However, reliable control is possible if much of the thickening agent is not crosslinked and the small amount of crosslinking required can be provided by selective crosslinking of only a small portion of the total thickening agent. .

This control is accomplished through the use of self-crosslinking gums that are selectively crosslinked by self-contained crosslinking agents.

In this way, the crosslinking agent does not have to be added separately to the composition, and the precise means of reliably adjusting the degree of crosslinking of the composition is by varying the amount of self-crosslinking thickening agent added as desired. achieved.

The invention will be better understood by reference to the examples described below.

Example 1 Compositions of the present invention are and can be generally prepared in the following manner.

The oxidant salts were dissolved in water to create a solution with a crystallization point of about 0°C.

After heating the solution to about 25°C or 30°C, water miscible liquid fuel and guar gum were added.

The resulting solution mixture was thickened and then mixed evenly with the remaining ingredients, including the self-crosslinking gum and starch paste.

Mixing and pumping is performed by conventional equipment.

This explosive had the following composition:

(ioo fraction depends on weight) AN
31.0 Section SN
19.0c10H2028,0% Ethylene Glycol 10.0 Guar Gum 0.33 Dapaint Grade Aluminum 1.5% Milled Aluminum
4.0% Sulfur 4.0% Pre-gelled cupioca starch 1.0% Brazilian tapioca starch 1.0% Self-crosslinking gum (EX-23) 0.15% A solution of this composition is crystallized. It had a temperature of -2°C.

At 30°C, this solution had a viscosity of 800-1200 centipoise.

It has a pH of 4.0 ± 0.2 and a pH of 1.3 at 30°C.
3,! i! / ct? It has a density of t.

At 5° C., the composition had a critical diameter (minimum packed diameter for successful wave propagation) of 20,000 to 20,000 inches at a density of 1.2111/cyyt.

The composition of this example is water resistant and can be poured from a 5 inch diameter polyethylene pack into a 3 inch diameter perforation or other container.

The present thickening agent system, which includes uncrosslinked guar gum, uncrosslinked starch, and self-crosslinked gum, is particularly effective.

This combination concomitantly provides high temperature (up to 60°C) stability and low temperature (up to 5°C) injectability.

Starch provides a thickening agent that is stable at high temperatures. Non-crosslinked gums provide good overall consistency of the liquid without adversely affecting pourability.

and self-crosslinking gums (J) that reduce viscosity and impart "stringiness" that increases pouring integrity and adds overall water resistance.

Example 2 Other compositions were prepared in the manner described above and had the formulations, properties and case results shown in Table 1 below.

All of these compositions are water resistant and can be poured from polyethylene bags into containers as large as 3 inches or smaller.

The composition does not stick unduly and has good stringing properties, thus maintaining integrity upon injection.

The compositions of the present invention can be packed into containers or packages of essentially any desired size and shape using conventional equipment.

They are preferably packed in elongated or cylindrical polyethylene bags having an average cross-sectional diameter of about 5 to about fin inches.

Packed compositions generally store about ■ under reasonable storage conditions
Has a safe and reliable shelf life of up to 20 years or more.

When using a packed explosive, the pack is opened or usually cut off at one end and the composition is "poured" out of the pack and into the desired container.

Even if the composition can be poured from the pack, it must be sufficiently thick, water resistant, and stable to have at least a minimum degree of crosslinking (generally from about 15,000 to about 75,000
centipoise) and thus can be poured into a container or perforation containing water, even after being placed in a perforation containing several centipoises (, >B).

The type of composition shown above? It can be poured into a 2-inch diameter container at 15,000 centipoise.

At 75,000 centipoise, the composition can still be poured into containers with a diameter of 2y2 to 3".

While the invention has been described with reference to some examples and selected embodiments, numerous modifications will be apparent to those skilled in the art.
Such modifications are considered to be within the scope of the invention as set forth in the claims.

Claims (1)

[Scope of Claims] 1 Selected from inorganic oxidizing agent salts, water, organic fuels, polysaccharide polymers selected from wheat flour, starch, and guar gum, and synthetic polymers selected from polyacrylamide and biopolymers. In an oil-in-water explosive composition comprising a non-crosslinking thickening agent and a self-crosslinking thickening agent, the content of the non-crosslinking thickening agent is 0.2 to 6 weight φ of the total composition,
The self-crosslinking thickening agent consists of a mixture of a crosslinking agent selected from antimony, borates and chromates, and guar gum, and the content thereof is 0.1 to 0.5% by weight of the total composition. A composition that maintains injectability into a small container, characterized by: 2 Dissolve 40 to 70 parts by weight of inorganic oxidizing agent salts in 10 to 40 parts by weight of warm water, and add organic fuel and a polysaccharide polymer and polysaccharide selected from flour, starch, and guar gum to the total composition. A non-crosslinking thickening agent selected from synthetic polymers selected from acrylamide and biopolymers, 0.2 to 6% by weight, a crosslinking agent selected from antimony, borates and chromates, and guar gum. A small container comprising a mixture of 0.1 to 0.5 weight φ of a self-crosslinking thickening agent added and mixed, characterized in that the amount of water is adjusted so that the crystal precipitation point is below the operating temperature. A method for producing an oil-in-water explosive composition that retains injectability.