Patent Application
20240132421
The present disclosure relates to emulsion-type explosives of the water-in-oil type.
Emulsion-type explosives have become increasingly more important in the civil explosives industry. The organic phase thus forms a thin film around the droplets of the oxidizer phase. Typical examples of commonly used fuels include diesel, paraffin wax, paraffin oil, slack wax and the like. In the organic phase, an emulsifier is added, which acts at the interface between the two phases to stabilize the emulsion. Due to its organic nature, the emulsifier is included in the stoichiometry of the explosion. Due to supersaturation and the immiscibility of the two phases that are mixed, an emulsion explosive is a metastable system. The emulsion is said to “break” when the organic phase and the oxidizer phase separate and/or some oxidizer crystallizes out of the oxidizer phase.
Ammonium nitrate (AN) emulsions used for mining applications normally use a non-renewable mineral fuel, typically diesel, as the main fuel. However, there is a demand for a “greener” solution (more environmentally friendly) and a more sustainable solution in view of the raw materials used in the explosive emulsion.
It is already known to use vegetable oils in explosive emulsions. However, it has been found that using vegetable oil exponentially increases the viscosity and this is a problem for many applications. The primary problem however with this kind of explosive emulsions is that there is a loss of stability of the emulsion. Emulsions are by nature unstable systems. Contrary to a classical emulsion in which the organic phase containing a classical, non-renewable fuel (e.g. diesel) is mixed with an aqueous ammonium nitrate solution i.e. a monosalt oxidizer phase, mixing the same oxidizer phase with the same emulsifier, and instead of diesel, a vegetable oil which by nature has a totally different chemistry and behavior than diesel, no emulsion will be formed, and if it forms, it will lead to an unstable emulsion that will break in a short time.
Patent documents often mention the use of vegetable oil as a trivial raw material to be used in explosive emulsions. However, after testing performed by the present inventors, it became clear that it is not trivial to replace large amounts of the usually used fuel, e.g. diesel or other petroleum derived fuels, i.e. non-renewable fuel, by a renewable oil, such as vegetable oil, because, after formation of the emulsion, the stability and viscosity thereof are problematic. This observation may be attributed to the different chemistry and properties of the non-renewable oils compared to renewable oils. In particular, the inventors have observed that monosalt emulsions with ammonium nitrate in the oxidizer phase and a fuel comprising vegetable oil in the organic phase does not form a stable emulsion.
There thus remains a need for a greener explosive emulsion in which the majority or the totality of the non-renewable oil is replaced by a renewable oil, which is a stable emulsion and which has a viscosity which can be adapted to be used in different applications, in particular which has a viscosity comparable to the viscosity of the monosalt emulsions of the prior art, having an ammonium nitrate oxidizer phase and a diesel oil fuel.
The inventors have surprisingly found that stable explosive emulsions comprising renewable oils, in particular a vegetable oil, as fuel can be obtained by adding a suitable amount of one or more secondary salts, in particular calcium nitrate. In particular embodiments, stable explosive emulsions with viscosities similar to explosive emulsions based on non-renewable fuel oils were also obtained with a fuel comprising both a bio-fuel, such as a hydrotreated vegetable oil (HVO), and a straight vegetable oil, when using a higher amount of one or more secondary salts in the oxidizer phase. Advantageously, the preparation method of the explosive emulsions of the present disclosure is similar to that of traditional monosalt AN/diesel based explosive emulsions, without the need to pre-emulsify the composition or the need for high shear stress device after pumping the explosive emulsion.
According to a first aspect of the present disclosure, an explosive emulsion composition of the water-in-oil type is disclosed, comprising
In a possible embodiment of an explosive composition according to the present disclosure, the explosive emulsion comprises between 85 wt. % and 95 wt. % oxidizer phase and between 5 wt. % and 15 wt. % organic phase, both in view of the total weight of the emulsion composition.
In an optional embodiment of an explosive composition according to the present disclosure, the fuel consists of between 0 wt. % and 50 wt. %, in particular between 0 wt. % and 30 wt. % of one or more non-renewable oils and 50 wt. % and between 100 wt. %, in particular between 70 wt. % and 100 wt. % of one or more renewable oils in view of the total weight of the fuel composition, particularly wherein said one or more renewable oils comprises a straight vegetable oils. The fuel more in particular consists of 100 wt. % of one or more renewable oils in view of the total weight of the fuel composition.
In an embodiment of an explosive composition according to the present disclosure, the oxidizer phase comprises between 40 wt. % and 75 wt. % of ammonium nitrate (AN) and between 25 wt. % and 50 wt. % of calcium nitrate (CN), in particular between 25 wt. % and 40 wt. % CN, and optionally one or more other secondary nitrate salts, all in view of the total weight of the oxidizer phase composition.
In an embodiment of an explosive composition according to the present disclosure, the oxidizer phase comprises between 5 wt. % and 25 wt. % of water in view of the total weight of the oxidizer phase composition.
In a possible embodiment of an explosive composition according to the present disclosure, the one or more emulsifiers are present in an amount of between 0.5 wt. % and 5.0 wt. %, more in particular between 1.0 wt. % and 2.5 wt. %, in view of the total weight of the total emulsion composition. The one or more emulsifiers are added to prevent separation of the different phases and thus to obtain a stable emulsion.
In a more particular embodiment of an explosive composition according to the present disclosure, the one or more emulsifiers are from a renewable source. In combination with 100 wt. % of one or more renewable oils, particularly comprising a SVO, in view of the total weight of the fuel composition, a fully green explosive emulsion is obtained.
In particular embodiments, the one or more renewable oils in the explosive composition according to the present disclosure typically comprise a straight vegetable oil and may further be chosen from
The straight vegetable oil may be chosen from chosen from soybean oil, palm oil, rapeseed oil, maize oil, corn oil, sunflower oil, ricin oil, coconut oil, jojoba oil, jatropha oil or a mixture thereof
More in particular, the renewable oil, particularly the straight vegetable oil, in an explosive emulsion composition according to the present disclosure has a viscosity of at least 20 cP at 40° C., in particular at least 25 cP at 40° C.
In a possible embodiment of an explosive emulsion composition according to the present disclosure, the explosive emulsion composition comprises
In a further optional embodiment of an explosive emulsion composition according to the present disclosure, the explosive emulsion comprises
The present disclosure relates to water-in-oil type emulsion explosives comprising an (aqueous) oxidizer (discontinuous) phase and an organic (continuous) phase. In general, the present disclosure provides stable, green explosive emulsions in which most or even all of the non-renewable oil in the organic phase as used in traditional explosive emulsions is replaced by one or more renewable oils and wherein the oxidizer phase generally comprises ammonium nitrate and at least one secondary nitrate salt. Advantageously, the viscosity of the explosive emulsions according to the present disclosure can be adapted to be used in different applications. The evaluation of the stability, in particular the shear stress stability, of an explosive emulsion composition is known to the skilled person and includes determining the number and size of crystal formed in the emulsion by means of a polarized light microscope analysis, as further explained below.
The explosive emulsion composition of the present disclosure generally comprises between 80 wt. % and 95 wt. % of an oxidizer phase and between 5 wt. % and 20 wt. % of an organic phase, both in view of the total weight of the emulsion composition. More in particular, the explosive emulsion composition comprises between 85 wt. % and 95 wt. %, or between 90 wt % and 95 wt. %, of an oxidizer phase and between 5 wt. % and 15 wt. %, or between 5 wt. % and 10 wt. %, of an organic phase in view of the total weight of the emulsion composition.
The organic phase of the explosive emulsion composition according to the present disclosure generally comprises between 1 wt. % and 8 wt. %, more in particular between 2 wt. % and 6.5 wt. %, between 2.5 wt. % and 6.5 wt. % or between 2 wt. % and 5 wt. %, even more in particular between 3.0 wt. % and 6.0 wt. %, or between 3 wt. % and 4.5 wt. % of a fuel composition, based on the total weight of the emulsion composition. The fuel composition as envisaged herein generally comprises between 20 wt. % and 100 wt. % of one or more renewable oils (meaning a single renewable oil or a mixture of different renewable oils) and may consists of between 0 wt. % and 50 wt. % of one or more non-renewable oils (meaning a single non-renewable oil or a mixture of different non-renewable oils), and between 50 wt. % and 100 wt. % of one or more renewable oils (meaning a single renewable oil or a mixture of different renewable oils), in view of the total weight of the fuel composition. More in particular, the one or more renewable oils have a viscosity of at least 20 cP or at least 25 cP at 40° C., as measured with a Brookfield viscometer.
More in particular, the fuel composition consists of between 0 wt. % and 40 wt. %, between 0 wt. % and 30 wt. %, between 0 wt. % and between 20 wt. % or between 0 wt. % and 10 wt. % of one or more non-renewable oils and between 60 wt. % and 100 wt. %, between 70 wt. % and 100 wt. %, between 80° wt. % and 100 wt. % or between 90 wt. % and 100 wt. % (respectively, of one or more renewable oils, in view of the total weight of the fuel composition. It is understood that the total weight % of the different oils needs to be equal to 100. In particular embodiments, the non-renewable oil is diesel or white oil.
More in particular, the fuel composition of the explosive emulsion composition according to the present disclosure comprise between 20 wt. % and 100 wt. %, such as between 30 wt. % and 100 wt. %, or between 40 wt. % and 100 wt. % of a straight vegetable oil (SVO), in view of the total weight of the fuel composition. The one or more renewable oils typically have a viscosity of at least 20 cP or at least 25 cP at 40° C., as e.g. measured with a Brookfield viscometer or by ASTM D445-19.
Advantageously, the combination of a fuel composition comprising a SVO and an oxidizer phase comprising ammonium nitrate and calcium nitrate as discussed below results in an explosive emulsion composition with stability and viscosity properties comparable to a monosalt AN/diesel based explosive emulsion of the prior art, and, hence, suitable for multiple applications.
In particular embodiments, the fuel composition consists of 100 wt. % of one or more renewable oils in view of the total weight of the fuel composition, particularly wherein said one or more renewable oils comprises a straight vegetable oil. The fuel composition may consist of between 0 wt. % and 100 wt. % or between 10 wt. % and 90 wt. % of one or more biofuels, more in particular one or more hydrotreated renewable oils (HVO), and between 0 wt. % and 100 wt. % or between 10 wt. % and 90 wt. % of one or more straight vegetable oils (SVO).
In particular, the fuel composition consists of between 20 wt. % and 80 wt. %, between 30 wt. % and 70 wt. % or between 40 wt. % and 60 wt. %, of one or more biofuels, more in particular one or more hydrotreated renewable oils (HVO), and between 20 wt. % and 80 wt. %, between 30 wt. % and 70 wt. % or between 40 wt. % and 60 wt. %, of one or more straight vegetable oils (SVO), wherein the total weight % of the one or more biofuels, in particular HVO, and the one or more SVO equals 100. Advantageously, the combination of a fuel composition comprising a SVO and a HVO (or another biofuel), and an oxidizer phase comprising ammonium nitrate and calcium nitrate as discussed below results in a stable explosive emulsion composition and allows for an even better control of the viscosity of the explosive emulsion of the present disclosure.
The one or more renewable oils can be chosen from a straight vegetable oil (SVO), a straight animal fat, a biofuel comprising bio-diesel, recycled vegetable oil, recycled animal fat or a hydrotreated renewable oil. Also a mixture of two of these can be applied.
A straight vegetable oil is defined as any of a group of oils that are esters of fatty acids and glycerol and are obtained from plants. In particular embodiments, the straight vegetable oil is chosen from soybean oil, palm oil, rapeseed oil, canola oil, maize oil, corn oil, sunflower oil or a mixture thereof. Less preferred SVO's which are economically less attractive, but which are also suitable, are groundnut oil, kernel oil, virgin olive oil, oil of olive residues, karite nuts butter, castor bean oil, hydrogenated castor oil, tung nuts oil, safflower seed oil, sesame seed oil, mustard seed oil, poppy seed oil, vegetable tallow, stillingia oil, kapok oil, cottonseed oil linseed oil, hempseed oil, rice bran oil, linseed oil, algae oil, peanut oil and safflower oil or a mixture thereof.
The straight animal fat can be cattle fat, buffalo fat, sheep fat, goats fat, pigs fat, poultry fat, camels fat, fat from other camelids, ghee fat or whale fat (blubber), fish oil or a mixture thereof. Animal fats tend to have more free fatty acids than vegetable oils do.
Bio-fuels are any type of transportation fuel that is derived from biomass including plant or algae material or animal waste. Bio-fuels are renewable.
Biodiesel is a form of diesel fuel derived from plants or animals and consisting of long-chain fatty acid esters. It is typically made by chemically reacting lipids such as animal fat (tallow), soybean oil or other vegetable oils with an alcohol, producing methyl, ethyl or propyl ester by a chemical process called esterification. Biodiesel has a lower boiling point and viscosity than SVO. Pure biodiesel is marketed as B100 at the gasoline stations.
Recycled vegetable oil or recycled animal fat originates from cooking such as frying or other industrial processes without intermediate processing.
Hydrotreated renewable oils, also referred to as hydrotreated vegetable oils or HVO, are paraffinic bio-based liquid oils originating from many kinds of vegetable oils, such as rapeseed, sunflower, soybean, and palm oil, as well as animal fats or rests from wood processing. As well understood by the skilled person, hydrotreated renewable or vegetable oils are obtained by subjecting fatty acid containing oils, such as vegetable oils or waste fats to a hydro-processing treatment or a hydrotreatment, wherein hydrogen is used to make paraffin and cycloalkanes out of the unsaturated compounds in the oils, which typically further undergo hydrocracking or isomerization. The term “hydrotreated vegetable oil” or HVO also refers to recycled vegetable oil, animal fats or waste fats, that have been subject to the hydrotreatment process.
The presence of a renewable oil in the organic phase causes a drop in emulsion stability. The inventors have surprisingly found that the emulsion stability is maintained when the oxidizer phase of the explosive emulsion composition of the present invention comprises next to ammonium nitrate (AN) as an oxidizer salt also a suitable amount of one or more of a secondary nitrate salt such as an alkaline earth metal nitrate salt, in particular calcium nitrate (CN), and/or an alkali metal nitrate salt, in particular sodium nitrate (SN). The oxidizer phase of the explosive emulsion composition according to the present disclosure generally comprises at least 40 wt. % of AN, particularly between 40 wt % and 80 wt % AN, more particularly between 40 wt % and 75 wt %, even more particularly between 40 wt % and 70 wt % or between 40 wt % and 65 wt %, in view of the total weight of the oxidizer phase composition.
The oxidizer phase may comprise at least 40 wt. % of AN, particularly between 40 wt % and 80 wt. % of AN, and at least 10 wt. % of CN, and, optionally, one or more other secondary nitrate salts, with wt. % in view of the total weight of the oxidizer phase composition.
In particular embodiments, the oxidizer phase comprises between 40 wt. % to 80 wt. % AN and between 15 wt. % and 50 wt. %, particularly between 20 wt. % and 50 wt. %, more particularly between 20 wt. % and 40 wt. % of calcium nitrate, and, optionally, one or more other secondary nitrate salts, such as sodium nitrate, with wt. % in view of the total weight of the oxidizer phase composition. In more particular embodiments, the oxidizer phase comprises between 40 wt. % to 75 wt. % AN or between 40 wt. % and 70 wt % of AN and between 25 wt. % and 50 wt. %, particularly between 30 wt. % and 50 wt. %, more particularly between 30 wt. % and 40 wt. % of calcium nitrate, and, optionally, one or more other secondary nitrate salts, such as sodium nitrate, with wt. % in view of the total weight of the oxidizer phase composition. Stated differently, the ratio AN:CN in the oxidizer phase ranges between 5:1 and 0.8:1, particularly ranges between 4:1 and 1:1 or between 3:1 and 1:1. Advantageously, the use of calcium nitrate as secondary nitrate salt in the concentrations considered herein in combination with a fuel composition comprising a vegetable oil in the concentrations considered elsewhere herein allows to obtain stable explosive emulsion compositions with a suitable viscosity range for multiple applications, particularly with a viscosity comparable to traditional monosalt AN/diesel based explosive emulsions. These explosive emulsion compositions according to the present disclosure have a viscosity between 25,000 cP and 125,000 cP, as measured with a Brookfield viscometer with spindle size 7 at a frequency of 20 rpm at 30° C.
Adding a biofuel such as a hydrotreated renewable oil lowers the viscosity of the composition. By adjusting the amount of biofuel added, the viscosity of the composition can be adjusted to the desired value, in particular to be even more similar to the viscosity of the traditional monosalt AN/diesel based explosive emulsions. This is particular the case when using CN as secondary nitrate salt, particularly at the concentrations discussed elsewhere herein. Accordingly, in particular embodiments, the explosive emulsion according to the present disclosure comprises
The explosive emulsion composition according to the present disclosure typically has a viscosity of between 10 000 and 200 000 cP, as measured with a Brookfield viscometer with spindle size 7 and frequency of 20 rpm, particularly as measured at a temperature between 20° C. and 80° C.
The oxidizer phase may also comprise at least 40 wt. % of AN, particularly between 40 wt % and 75 wt. % of AN, and at least 20 wt. % CN, SN, or a mixture thereof, particularly between 20 wt % and 50 wt. % CN, SN, or a mixture thereof, more particularly between 20 wt % and 40 wt. % CN, SN, or a mixture thereof, even more particularly between 20 wt. % and 35° wt. % or between 25 wt. % and 35 wt. % CN, SN or a mixture thereof, with wt/% in view of the total weight of the oxidizer phase composition. When the explosive emulsion composition comprises SN as a secondary salt, the viscosity of the composition is very high. However, a high viscosity is an issue for many applications as it becomes almost impossible to pump into the bore hole. Accordingly, an explosive emulsion composition according to the present disclosure comprising SN in the concentrations considered herein in combination with a fuel composition comprising a vegetable oil in the concentrations considered elsewhere herein may be suitable for use in packaged emulsion (cartridge) applications.
The oxidizer phase of the explosive emulsion composition according to the present disclosure further typically comprises between 5 wt. % and 25 wt. % or between 7 wt. % and 25 wt. % of (de-ionized) water in view of the total weight of the oxidizer composition. More in particular, the amount of water present in the oxidizer phase is between 10 wt. % and 20 wt. %, such as between 12 wt. % and 17 wt. % or about 15 wt. %.
The organic phase of the explosive emulsion composition according to the present disclosure furthermore comprises an emulsifier which is added to prevent separation of the different phases and thus to obtain a stable emulsion. Particular emulsifiers include, but are not limited to PIB (polyisobutylene) derivatives such as PIBSA (polyisobutylene succinic anhydrides), sorbitan ester emulsifiers such as SMO (sorbitan monooleate) and mixtures thereof. It is however remarked that other types of emulsifiers, leading also to highly stable emulsions, could be used. In this context, the emulsifier may be chosen from the wide range of emulsifiers known in the art to be suitable for the preparation of explosive emulsion compositions. The emulsifier can be bio-sourced, i.e. produced from renewable resources. When the fuel is also completely from a renewable origin, providing an emulsifier which is bio-sourced provides a fully green solution of an explosive emulsion.
Typically, between 12 wt. % and 50 wt. % of one or more emulsifiers (meaning a single emulsifier or a mixture of different emulsifiers) in view of the total weight of the organic phase composition is present. Typical amounts of such emulsifiers in view of the total weight of the emulsion composition are between 0.5 and 5 wt. %, more in particular between 1.0 wt. % and 2.5 wt. %.
Adding a biofuel such as a hydrotreated renewable oil lowers the viscosity of the composition. By adjusting the amount of biofuel added, the viscosity of the composition can be adjusted. This is particular the case when using CN as secondary nitrate salt.
The explosive emulsion composition typically has a viscosity of between 10 000 and 200 000 cP, as measured with a Brookfield viscometer with spindle size 7 and frequency of 20 rpm, particularly as measured at a temperature between 20° C. and 80° C.
In particular embodiments, the explosive emulsion composition according to the present disclosure comprises
wherein the explosive emulsion composition has a viscosity between 25,000 cP and 125,000 cP, as measured with a Brookfield viscometer with spindle size 7 at a frequency of 20 rpm at 30° C.
In particular, the explosive emulsion composition comprises between 2.5 wt. % and 6.5 wt. %, particularly between 3.0 wt. % and 6.0 wt. % of a fuel composition, in view of the total weight of the emulsion composition.
In particular embodiments, the explosive emulsion composition according to the present disclosure comprises
In certain embodiments, the explosive emulsion composition according to the present disclosure may comprise
In certain embodiments, the explosive emulsion according to the present disclosure may comprise
In certain embodiments, the explosive emulsion composition according to the present disclosure may comprise
In certain embodiments, the explosive emulsion composition according to the present disclosure may comprise
In certain embodiments, the explosive emulsion composition according to the present disclosure may comprise
In certain embodiments, the explosive emulsion composition according to the present disclosure may comprise
In Table 1 below, an overview is given of the tested samples of explosive emulsions, produced by the following procedure:
The following materials are used:
The following emulsifiers were used in the tests as shown in Table 1:
The following samples as produced by the procedure as described above were tested:
The shear stress stability of the different tested samples as mentioned in Table 1 as mentioned in Table 3 below was measured by the following method:
The viscosity as mentioned in Table 3 below of the different tested samples as
mentioned in Table 1 was measured using the following measurement method: a spindle of a Brookfield viscometer with spindle size 7 at a frequency of 20 rpm is rotated for 30 s (this time being an optional choice in the viscometer settings). The viscosity of the following emulsions is measured as:
Out of results as shown in Table 3, it can be concluded that:
| Number | Date | Country | Kind |
|---|---|---|---|
| 21161191.8 | Mar 2021 | EP | regional |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2022/055797 | 3/8/2022 | WO |
