Oxidizer solution

[0001] In most countries where bulk explosives are used, they fall into the category defined in the United Nations Handbook on the Transportation of Dangerous Goods as emulsion suspensions or ammonium nitrate gels (abbreviated ANE, ammonium nitrate emulsions) and are transported and stored as oxidants 5.1 with UN No. 3375. As the name suggests, they are in the form of water emulsions or gels (or sludges). Because they are not classified as explosives, the provisions on transport and storage are much less demanding than if they were classified as explosives. Such ANE undergo sensitization by becoming explosive when pumped into the blast hole by mechanical gas entrainment or by adding a chemical explosive during the pumping process.

[0002] One of the problems encountered with existing bulk explosive (water gel or emulsion) formulations is that they are extremely viscous fluids and cause difficulties in pumping or transporting in pipelines over long distances. This is not usually a problem in opencast mining, where vehicle access is simply a matter of reaching a powered hole and inserting the charging hose into the hole, and then pumping the explosive into the hole. However, when using loose products in underground applications, it would be very convenient to be able to place the pumping unit in a location at a certain distance from the powered working face and simply pass the long hose into the powered aperture.

[0003] The second problem is above all the problem of bringing explosive material underground. Because this must be done by transporting it in containers using the same lift devices or access routes used for people, equipment and ore, this can seriously interfere with production. Since they are non-explosive until pumping into the blasting hole, it is at least theoretically possible to pump them through a long pipeline to the point where they are needed underground. Here again, the problem is the viscosity, because there is a finite distance limit at which a highly viscous fluid can be pumped, taking into account the energy nature of the material being pumped, and thus limiting to the maximum inflation pressure to which it can be exposed.

[0004] The physical properties of the ANE are another limitation imposed over a distance that can be transported in the pipeline. In the case of ANE type water gel or sludge, the product is a saturated solution of oxidizing salts and soluble fuels thickened with a kind of thickener (usually guar gum) with which further amounts of oxidizing salts and (optionally) insoluble fuels are mixed. When pumping such a slurry through a very long line there is a risk of the solid blocking of the line by the solids and the complete stop of the pumping process. If one were to consider dumping or pumping such a suspension through a long vertical (or inclined) pipe to be brought underground, the risk of blocking the pipeline would be so great that it would be an imprudent activity. In the case of ANE emulsion type, such emulsions are prepared by preparing a solution of oxidizing salts in water at elevated temperature, followed by emulsifying this solution in the phase of a fuel composed of oil and an emulsifier, and then allowing the emulsion to cool to ambient temperature. Due to the very small size of the emulsion micelles, salts can not be recrystallised. It should be remembered that the emulsion fuel phase represents only about 6% or 7% of the product and that it is a continuous phase. Salt solution that the emulsion fuel phase represents only about 6% or 7% of the product and that it is a continuous phase. Salt solution that the emulsion fuel phase represents only about 6% or 7% of the product and that it is a continuous phase. Salt solution

The oxidation state constitutes more than 90% of the emulsion and it is a dispersed phase. This means that the cell walls around the droplets of the oxidant solution are extremely thin and stretched and that if these cell walls break for any reason, the droplets of the oxidant solution will start to cluster, and when the micelles become quite large, the salts will crystallize from the solution. When this happens, the growing crystals will begin to pierce successive micelle walls and the emulsion will rapidly disintegrate and the salts will crystallize because they are well below their crystallization temperature. When this happens, the whole mass will solidify and it will cease to be a pumpable liquid. If you are considering transporting the emulsion from the surface to the ground through a long pipeline, the risk of degradation of the emulsion during transport must be considered, and if this happens,

[0005] Theft is also a serious problem for both packaged explosives and bulk explosives used in the mining industry. Stolen explosives may be in the hands of criminals or terrorists and pose a serious threat to society.

[0006] The object of the present invention is to find a solution to these problems.

[0007] US3645809 discloses explosives in the form of an aqueous sludge with an improved oxidizer-fuel system.

[0008] EP1375456 discloses a method for the preparation of "in situ" mixtures of explosives.

[0009] WO2009 / 000915 discloses explosive-sensitive explosive emulsion emulsion compositions containing supersaturated ammonium nitrate, an emulsifying agent and a crystallization lowering agent and methods for their preparation.

[0010] US3996078 discloses an explosive composition and a eutectic mixture for it.

SUMMARY OF THE INVENTION [0011] According to the present invention there is provided an aqueous oxidant solution consisting of a mixture of dissolved oxidizing nitrate salts with from 12% to 24% by weight of water, for use in the manufacture of explosives, which has a crystallization temperature of 10 ° C or lower, as low as 5 ° C or less, even as low as 0 ° C or less, the solution containing:

ammonium nitrate; and calcium nitrate or a mixture of calcium nitrate and magnesium nitrate, preferably calcium nitrate; wherein the molar concentration of ammonium nitrate relative to calcium nitrate or a mixture of calcium nitrate and magnesium nitrate is from 0.75: 1 to 1.25: 1 and more preferably approximately 1; and alkylamine nitrate or monoethanolamine nitrate present in an amount of 10% to 18% by weight.

[0012] By "crystallization temperature" is meant the temperature at which one or more dissolved oxidizing salts start to precipitate from the oxidant solution.

[0013] When the solution comprises a mixture of calcium nitrate and magnesium nitrate, the molar ratio of calcium nitrate to magnesium nitrate should not be less than about 4: 1, and preferably not less than about 4.5: 1.

[0014] The oxidant solution contains water in an amount of from 12% to 24%, preferably from 17% to 22% by weight.

[0015] Alkylamine nitrate or monoethanolamine nitrate is present in an amount of 10% to 18% by weight, or from 12% to 17% by weight.

[0016] For every 1% reduction in the water content below 24%, the solution preferably comprises at least

A further 1.67% alkylamine nitrate or monoethanolamine nitrate was added to keep the crystallization temperature low. In other words, the alkylamine nitrate or monoethanolamine nitrate is preferably present in at least an amount that satisfies the equation: M> 5 (24-W) / 3 (where W = the percentage of water in solution and M = the percentage of alkylamine nitrate or monoethanolamine nitrate in solution).

[0017] The alkylamine nitrate may be methylamine nitrate (also referred to as monomethylammonium nitrate), dimethylamine nitrate or trimethylamine nitrate, preferably methylamine nitrate.

[0018] This solution can be used to produce an aqueous gel or emulsion of explosives or ANE. Other nitrates, such as magnesium nitrate, sodium nitrate and potassium nitrate may be included, but they must be present in molar concentrations much lower than calcium nitrate.

[0019] The invention also encompasses a process for preparing a formulation of explosives by mixing the oxidant solution described above with the fuel.

[0020] The invention further comprises a usable form of explosives comprising a mixture of the oxidant solution described above with the fuel.

[0021] The fuel may be a hydrocarbon fuel, such as a diesel fuel, paraffin, oil, etc., a water-soluble alcohol or polyol (e.g., monoethylene glycol, glycerol, ethanol, methanol, propanol), a water-soluble carbohydrate such as sugar . In general, if an ANE type of an aqueous gel is prepared, water-soluble fuel may well be chosen, however, incompatible fuels can also be used with great success for the production of an aqueous gel. If an emulsion type ANE is made, one of the hydrocarbon fuels mentioned above or even a lubricating oil or other from a recovery, such as vegetable oil, will be selected.

DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION [0022] The present patent application claims priority to the provisional GB patent application No. 1202402.

[0023] I have invented an aqueous oxidizer solution containing a mixture of dissolved oxidizing salts containing from 12% to 24% by weight of water that does not crystallize below 10 ° C, and even 0 ° C or less (as low as -7 ° C), and which can be use for the production of an aqueous gel or emulsion explosive or ANE (emulsion suspension or ammonium nitrate gel), provided that it meets the following criteria:

1) The solution contains less than an amount of between 12% and 24% by weight of water;

2) The solution contains ammonium nitrate (NH4NO3) and calcium nitrate (Ca (NO3) 2) in molar ratio of ammonium nitrate to calcium nitrate from 0.75: 1 to 1.25: 1, more preferably as close to 1: 1 as possible; and

3) When the water content in the solution drops below 24%, at least 1.67% of monomethyl ammonium nitrate (CH3NH3NO3, also known as methylamine nitrate) is added for every 1% of water removed from the solution. In other words, the content of monomethyl ammonium nitrate should meet the equation: M> 5 (24-W) / 3 (where W = the percentage of water in solution and M = the percentage of monomethylammonium nitrate in solution).

[0024] Since the molecular weight of ammonium nitrate is 80,043 and the molecular weight of calcium nitrate is 164,086, condition 2) may be expressed differently (for example): The solution contains ammonium nitrate and calcium nitrate in a ratio of calcium nitrate to ammonium nitrate from 4.1: 1 to 1.37: 1 and preferably from 2.73: 1 to 1.64: 1 and preferably as close to 2.05: 1 as possible.

[0025] If desired, an amount of calcium nitrate may be replaced with magnesium nitrate (i.e., use of a calcium nitrate / magnesium nitrate mixture), provided that the molar ratio of nitrate is

The ammonium up to the sum of molar concentrations of calcium nitrate and magnesium nitrate will be from 0.75: 1 to 1.25: 1 and more preferably as close to 1: 1 as possible. Furthermore, the molar ratio of calcium nitrate to magnesium nitrate should not be less than about 4: 1 and preferably not less than about 4.5: 1. Sodium nitrate and / or potassium nitrate can also be introduced, but in this case, in order to obtain a crystallization temperature below zero, the control factor is the molar ratio of ammonium nitrate and calcium nitrate, as well as the relative percentages of water and monomethyl ammonium nitrate, and the amount of nitrate sodium or potassium that can be introduced is mainly determined by their solubility in available water.

[0026] This solution can then be used to produce (among others) an aqueous gel or emulsion of explosives or ANE. It can be most preferably easily transported underground in deep mines through pipelines of relatively small diameter, using existing roads and access shafts, to work stations where they can then be converted to an explosive in the form of a water gel or emulsion or ANE.

[0027] When using the oxidant solutions of the present invention for the production of explosives as an emulsion, it is possible to transport the oxidant solution and the fuel / emulsifier mixture separately and generate the emulsion at the application site in such a way that if the explosive is left unused for more than a few days (for example), the emulsion will separate and the material will become non-explosive due to the nature of the unstable nature of each emulsion. This new system can be a big step in the fight against criminal activity and terrorism, because it makes the theft of explosives unattractive due to the extremely low shelf life of the final explosive. Of course, since both components of the emulsion are liquids, there is no practical distance limit to which they can be transported in the pipeline,

[0028] Furthermore, the free-flowing characteristic of this product is such that pumping over a long hose does not pose any problems. In the situation of extraction in a narrow vein, the pumping unit can be placed in a safe position and a hose from this point to the working anvil can be conveyed. After the transfer, the miner should roll up the hose and the next day, when the ancestor is cleaned, expand the hose to the new working ancestor and send it again. It will probably not be necessary to move the pumping unit more than once a month, which will save a lot of time and manpower.

[0029] The invention is described below in more detail with reference to the following Examples and comparative examples indicated by an asterisk after the mixture number.

[0030] In the Examples described below, the solutions were prepared from an 80% solution of monomethyl ammonium nitrate and either solid ammonium nitrate or 88% ammonium nitrate solution as well as agricultural calcium nitrate produced by the South African OMNIA Fertilizer Ltd and sold under the OMNICAL ™ brand name, which contains about 80% calcium nitrate and about 15% water, with the remainder being ammonium nitrate. The reason for using this, not chemically pure material, is that the standard chemically pure calcium nitrate contains 30.5% water in the form of water of crystallization, and using agricultural material I could produce solutions containing significant amounts of calcium nitrate while maintaining relatively low water levels. The mixture was then heated to form a clear solution, which was then cooled with stirring,

EP 2 812 295 [0031] The invention is illustrated by means of certain examples shown in Table 1 below:

Table 1:

<td>Mix number</td><td>A1 *</td><td>A2 *</td><td>A3</td><td>A4</td><td>A5</td><td>A6 *</td><td>A7 *</td><td>A8 *</td>

<td>Ammonium nitrate (AN) (%)</td><td>6.6</td><td>12.0</td><td>16.3</td><td>20.0</td><td>23.1</td><td>25.8</td><td>28.1</td><td>30.1</td>

<td>Calcium nitrate (CN) (%)</td><td>54.4</td><td>49.0</td><td>44.7</td><td>41.0</td><td>37.9</td><td>35.2</td><td>32.9</td><td>30.9</td>

<td>Moli AN / moles of CN</td><td>0.25</td><td>0.50</td><td>0.75</td><td>1.00</td><td>1.25</td><td>1.50</td><td>1.75</td><td>2.00</td>

<td>Water (%)</td><td>22.0</td><td>22.0</td><td>22.0</td><td>22.0</td><td>22.0</td><td>22.0</td><td>22.0</td><td>22.0</td>

<td>Monomethylammonium nitrate (%)</td><td>17.0</td><td>17.0</td><td>17.0</td><td>17.0</td><td>17.0</td><td>17.0</td><td>17.0</td><td>17.0</td>

<td>Crystallization temperature (° C)</td><td>16</td><td>4</td><td>-7</td><td>-6</td><td>3</td><td>6</td><td>11</td><td>14</td>

<td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td>

<td>Mix number</td><td>B1 *</td><td>B2 *</td><td>B3 *</td><td>B4 *</td><td>B5 *</td><td>B6 *</td><td>B7 *</td><td>B8 *</td>

<td>Ammonium nitrate (AN) (%)</td><td>7.0</td><td>12.5</td><td>17.1</td><td>21.0</td><td>24.2</td><td>27.0</td><td>29.5</td><td>31.6</td>

<td>Calcium nitrate (CN) (%)</td><td>57.0</td><td>51.5</td><td>46.9</td><td>43.0</td><td>39.8</td><td>37.0</td><td>34.5</td><td>32.4</td>

<td>Moli AN / moles of CN</td><td>0.25</td><td>0.50</td><td>0.75</td><td>1.00</td><td>1.25</td><td>1.50</td><td>1.75</td><td>2.00</td>

<td>Water (%)</td><td>22.0</td><td>22.0</td><td>22.0</td><td>22.0</td><td>22.0</td><td>22.0</td><td>22.0</td><td>22.0</td>

<td>Monomethylammonium nitrate (%)</td><td>14.0</td><td>14.0</td><td>14.0</td><td>14.0</td><td>14.0</td><td>14.0</td><td>14.0</td><td>14.0</td>

<td>Crystallization temperature (° C)</td><td>6</td><td>3</td><td>-4</td><td>-4</td><td>3</td><td>8</td><td>13</td><td>17</td>

<td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td>

<td>Mix number</td><td>C1 *</td><td>C2 *</td><td>C3</td><td>C4</td><td>C5</td><td>C6 *</td><td>C7 *</td><td>C8 *</td>

<td>Ammonium nitrate (AN) (%)</td><td>7.3</td><td>13.1</td><td>17.9</td><td>22.0</td><td>25.4</td><td>28.3</td><td>30.9</td><td>33.1</td>

<td>Calcium nitrate (CN) (%)</td><td>59.7</td><td>53.9</td><td>49.1</td><td>45.0</td><td>41.6</td><td>38.7</td><td>36.1</td><td>33.9</td>

<td>Moli AN / moles of CN</td><td>0.25</td><td>0.50</td><td>0.75</td><td>1.00</td><td>1.25</td><td>1.50</td><td>1.75</td><td>2.00</td>

<td>Water (%)</td><td>22.0</td><td>22.0</td><td>22.0</td><td>22.0</td><td>22.0</td><td>22.0</td><td>22.0</td><td>22.0</td>

<td>Monomethylammonium nitrate (%)</td><td>11.0</td><td>11.0</td><td>11.0</td><td>11.0</td><td>11.0</td><td>11.0</td><td>11.0</td><td>11.0</td>

<td>Crystallization temperature (° C)</td><td>38.8</td><td>20.5</td><td>-6</td><td>-5</td><td>3</td><td>9</td><td>15</td><td>18</td>

[0032] These results show that at constant water amounts, even when the water content is relatively high (22%), the crystallization temperature is much higher than 0 ° C when the molar ratio of ammonium nitrate to calcium nitrate is outside the range 0, 5: 1 to 1.5: 1 and is always below 0 ° C when the molar ratio of ammonium nitrate to calcium nitrate is 1: 1.

Table 2:

<td>Mix number</td><td>G1 *</td><td>G2 *</td><td>G3</td><td>G4</td><td>G5</td><td>G6 *</td><td>G7 *</td><td>G8 *</td>

<td>Ammonium nitrate (AN) (%)</td><td>7.3</td><td>13.3</td><td>18.2</td><td>22.3</td><td>25.8</td><td>28.7</td><td>31.3</td><td>33.6</td>

<td>Calcium nitrate (CN) (%)</td><td>59.5</td><td>54.7</td><td>49.8</td><td>45.7</td><td>42.2</td><td>39.3</td><td>36.7</td><td>34.4</td>

<td>Moli AN / moles of CN</td><td>0.25</td><td>0.50</td><td>0.75</td><td>1.00</td><td>1.25</td><td>1.50</td><td>1.75</td><td>2.00</td>

<td>Water (%)</td><td>15.6</td><td>15.0</td><td>15.0</td><td>15.0</td><td>15.0</td><td>15.0</td><td>15.0</td><td>15.0</td>

<td>Monomethylammonium nitrate (%)</td><td>17.6</td><td>17.0</td><td>17.0</td><td>17.0</td><td>17.0</td><td>17.0</td><td>17.0</td><td>17.0</td>

<td>Crystallization temperature (° C)</td><td>27</td><td>18</td><td>-4</td><td>-4</td><td>8</td><td>19</td><td>22</td><td>28</td>

<td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td>

<td>Mix number</td><td>H1 *</td><td>H2 *</td><td>H3</td><td>H4</td><td>H5</td><td>H6 *</td><td>H7 *</td><td>H8 *</td>

<td>Ammonium nitrate (AN) (%)</td><td>7.6</td><td>13.9</td><td>19.0</td><td>23.3</td><td>26.9</td><td>30.0</td><td>32.7</td><td>35.1</td>

<td>Calcium nitrate (CN) (%)</td><td>62.7</td><td>57.1</td><td>52.0</td><td>47.7</td><td>44.1</td><td>41.0</td><td>38.3</td><td>35.9</td>

<td>Moli AN / moles of CN</td><td>0.25</td><td>0.50</td><td>0.75</td><td>1.00</td><td>1.25</td><td>1.50</td><td>1.75</td><td>2.00</td>

<td>Water (%)</td><td>15.4</td><td>15.0</td><td>15.0</td><td>15.0</td><td>15.0</td><td>15.0</td><td>15.0</td><td>15.0</td>

<td>Monomethylammonium nitrate (%)</td><td>14.3</td><td>14.0</td><td>14.0</td><td>14.0</td><td>14.0</td><td>14.0</td><td>14.0</td><td>14.0</td>

<td>Crystallization temperature (° C)</td><td>54.5</td><td>37.5</td><td>17.6</td><td>4</td><td>10</td><td>18</td><td>25</td><td>28</td>

<td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td>

<td>Mix number</td><td>J1 *</td><td>J2 *</td><td>J3</td><td>J4</td><td>J5</td><td>J6 *</td><td>J7 *</td><td>J8 *</td>

<td>Ammonium nitrate (AN) (%)</td><td>8.0</td><td>14.5</td><td>19.8</td><td>24.3</td><td>28.0</td><td>31.3</td><td>34.1</td><td>36.5</td>

<td>Calcium nitrate (CN) (%)</td><td>65.8</td><td>59.5</td><td>54.2</td><td>49.7</td><td>46.0</td><td>42.7</td><td>39.9</td><td>37.5</td>

<td>Moli AN / moles of CN</td><td>0.25</td><td>0.50</td><td>0.75</td><td>1.00</td><td>1.25</td><td>1.50</td><td>1.75</td><td>2.00</td>

<td>Water (%)</td><td>15.1</td><td>15.0</td><td>15.0</td><td>15.0</td><td>15.0</td><td>15.0</td><td>15.0</td><td>15.0</td>

<td>Monomethylammonium nitrate (%)</td><td>11.1</td><td>11.0</td><td>11.0</td><td>11.0</td><td>11.0</td><td>11.0</td><td>11.0</td><td>11.0</td>

<td>Crystallization temperature (° C)</td><td>53</td><td>48</td><td>25</td><td>17</td><td>9</td><td>17</td><td>27</td><td>32</td>

[0033] These results show that for solutions with a low water content, if the nitrate content

EP 2 812 295 of monomethylammone falls below a certain level, the solution still having a minimum crystallization temperature when the molar ratio of ammonium nitrate to calcium nitrate falls within the range 0.75: 1 to 1.25: 1, it has a minimum no longer below 0 ° C. Although the crystallization temperature lower than zero is almost certainly unnecessary for handling and underground use, it is certainly very beneficial during transport to the mine, as well as for storage at both the production site and the mine. It is important that a method for minimizing the crystallization temperature of the oxidant solution is disclosed while maintaining relatively low water levels, which in turn allows for the production of an explosive at the final application site, which has enough energy to perform well when rocking.

Table 3:

<td>Mix number</td><td>Z1 *</td><td>Z2 *</td><td>Z3 *</td>

<td>Ammonium nitrate (AN) (%)</td><td>26.2</td><td>25.6</td><td>24.9</td>

<td>Calcium nitrate (CN) (%)</td><td>53.8</td><td>52.4</td><td>51.1</td>

<td>Moli AN / moles of CN</td><td>1.00</td><td>1.00</td><td>1.00</td>

<td>Water (%)</td><td>20.0</td><td>22.0</td><td>24.0</td>

<td>Monomethylammonium nitrate (%)</td><td>0</td><td>0</td><td>0</td>

<td>Crystallization temperature (° C)</td><td>18</td><td>11</td><td>-3</td>

[0034] The results above show that when the molar ratio of ammonium nitrate to calcium nitrate is 1: 1, if the water content in the solution is 24% or more, monomethylammonium nitrate is unnecessary to obtain a crystallization temperature below zero.

Table 4:

<td>Mix number</td><td>G4</td><td>G4A</td><td>order G4b</td><td>H4</td>

<td>Ammonium nitrate (AN) (%)</td><td>22.3</td><td>22.6</td><td>23.0</td><td>23.3</td>

<td>Calcium nitrate (CN) (%)</td><td>45.7</td><td>46.4</td><td>47.0</td><td>47.7</td>

<td>Moli AN / moles of CN</td><td>1.00</td><td>1.00</td><td>1.00</td><td>1.00</td>

<td>Water (%)</td><td>15.0</td><td>15.0</td><td>15.0</td><td>15.0</td>

<td>Monomethylammonium nitrate (%)</td><td>17.0</td><td>16.0</td><td>15.0</td><td>14.0</td>

<td>Crystallization temperature (° C)</td><td>-4</td><td>-4</td><td>-1</td><td>4</td>

[0035] The results above indicate that at a water content of 15%, if the monomethyl ammonium nitrate content is 15%, the crystallization temperature can be still below zero provided that the molar ratio of ammonium nitrate to calcium nitrate is 1: 1.

[0036] In Table 5 below, a series of results for solutions was reviewed where the molar ratio of ammonium nitrate (AN) to calcium nitrate (CN) was maintained at 1: 1, while the water content was reduced in steps of 1% from 24% to 14%, while the content of monomethyl ammonium nitrate (MMAN) was increased from 0 to 16.67% in steps of 1.67%. In each individual case, the crystallization temperature remained below 0 ° C.

Table 5:

<td>Mix number</td><td>K1 *</td><td>K2 *</td><td>K3 *</td><td>K4 *</td><td>K5 *</td><td>K6 *</td><td>K8</td><td>K9</td><td>K10</td><td>K11</td><td>K12</td>

<td>AN%</td><td>24.9</td><td>24.7</td><td>24.5</td><td>24.3</td><td>24.0</td><td>23.8</td><td>23.6</td><td>23.4</td><td>23.2</td><td>23.0</td><td>22.7</td>

<td>% CN</td><td>51.1</td><td>50.6</td><td>50.2</td><td>49.7</td><td>49.3</td><td>48.8</td><td>48.4</td><td>47.9</td><td>47.5</td><td>47.0</td><td>46.6</td>

<td>Moli AN / moles of CN</td><td>1.0</td><td>1.0</td><td>1.0</td><td>1.0</td><td>1.0</td><td>1.0</td><td>1.0</td><td>1.0</td><td>1.0</td><td>1.0</td><td>1.0</td>

<td>% water</td><td>24.0</td><td>23.0</td><td>22.0</td><td>21.0</td><td>20.0</td><td>19.0</td><td>18.0</td><td>17.0</td><td>16.0</td><td>15.0</td><td>14.0</td>

<td>% MMAN</td><td>0.00</td><td>1.67</td><td>3.33</td><td>5.00</td><td>6.67</td><td>8.33</td><td>10.00</td><td>11.67</td><td>13.33</td><td>15,00</td><td>16.67</td>

<td>Crystallization temperature CC)</td><td>-3</td><td>-3</td><td>-4</td><td>-4</td><td>-2</td><td>-5</td><td>-3</td><td>-2</td><td>-2</td><td>-1</td><td>-5</td>

[0037] In Table 6 below, a series of results for solutions was reviewed, where the molar ratio of ammonium nitrate (AN) to calcium nitrate (CN) was again maintained at 1: 1, while the water content was maintained

EP 2 812 295 was again reduced in steps of 1% from 24% to 14%, while the content of monomethyl ammonium nitrate (MMAN) was increased from 0 to 20% in 2% steps. In each individual case, the crystallization temperature remained below 0 ° C.

Table 6:

<td>Mix number</td><td>L1 *</td><td>L2 *</td><td>L3 *</td><td>L4 *</td><td>L5 *</td><td>L6</td><td>L7</td><td>L8</td><td>L9</td><td>L10</td><td>L11 *</td>

<td>% AN</td><td>24.9</td><td>24.6</td><td>24.3</td><td>23.9</td><td>23.6</td><td>23.3</td><td>23.0</td><td>22.6</td><td>22.3</td><td>22.0</td><td>21.6</td>

<td>% CN</td><td>51.1</td><td>50.4</td><td>49.7</td><td>49.1</td><td>48.4</td><td>47.7</td><td>47.0</td><td>46.4</td><td>45.7</td><td>45.0</td><td>44.4</td>

<td>Moli AN / moles of CN</td><td>1.0</td><td>1.0</td><td>1.0</td><td>1.0</td><td>1.0</td><td>1.0</td><td>1.0</td><td>1.0</td><td>1.0</td><td>1.0</td><td>1.0</td>

<td>% water</td><td>24.0</td><td>23.0</td><td>22.0</td><td>21.0</td><td>20.0</td><td>19.0</td><td>18.0</td><td>17.0</td><td>16.0</td><td>15.0</td><td>14.0</td>

<td>% MMAN</td><td>0.0</td><td>2.0</td><td>4.0</td><td>6.0</td><td>8.0</td><td>10.0</td><td>12.0</td><td>14.0</td><td>16.0</td><td>18.0</td><td>20.0</td>

<td>Crystallization temperature (° C)</td><td>-6</td><td>-6</td><td>-5</td><td>-7</td><td>-6</td><td>-6</td><td>-5</td><td>-6</td><td>-6</td><td>-5</td><td>-4</td>

[0038] The two above sets of results show that maintaining these constant ratios leads to surprisingly consistent crystallization temperatures.

[0039] Magnesium nitrate may be introduced into the solution and the crystallization temperature still remains below zero provided that the molar ratio of calcium nitrate to magnesium nitrate does not fall below about 4.0: 1 and preferably this ratio does not fall below about 4.25: 1 and most preferably that this ratio does not fall below 4.5: 1, moreover the molar ratio of ammonium nitrate to the sum of molar concentrations of calcium nitrate and magnesium nitrate must be as close to 1: 1 as possible.

[0040] This is demonstrated by the results shown in Table 7 below, in which MN refers to magnesium nitrate:

Table 7:

<td>Mix number</td><td>N1 *</td><td>N2</td><td>N3</td><td>N4</td><td>N5 *</td><td>N6 *</td><td>N7</td><td>N8</td><td>N9</td>

<td>% AN</td><td>13.5</td><td>18.3</td><td>22.4</td><td>25.8</td><td>28.8</td><td>18</td><td>22.5</td><td>25.9</td><td>22.5</td>

<td>% CN</td><td>45</td><td>41.0</td><td>37.6</td><td>34.7</td><td>32.2</td><td>39</td><td>35.5</td><td>32.8</td><td>32.9</td>

<td>% MN</td><td>9</td><td>8.2</td><td>7.5</td><td>6.9</td><td>6.4</td><td>10.5</td><td>9.6</td><td>8.8</td><td>12.1</td>

<td>Moli CN / moles MN</td><td>4.5</td><td>4.5</td><td>4.5</td><td>4.5</td><td>4.5</td><td>3.4</td><td>3.4</td><td>3.4</td><td>2.46</td>

<td>Moli AN / (moles CN + moles MN)</td><td>0.50</td><td>0.75</td><td>1.00</td><td>1.25</td><td>1.50</td><td>0.73</td><td>1.00</td><td>1.25</td><td>1.00</td>

<td>Moli AN / moles of CN</td><td>0.61</td><td>0.92</td><td>1.22</td><td>1.53</td><td>1.83</td><td>0.95</td><td>1.30</td><td>1.62</td><td>1.40</td>

<td>% water</td><td>18.5</td><td>18.5</td><td>18.5</td><td>18.5</td><td>18.5</td><td>18.5</td><td>18.5</td><td>18.5</td><td>18.5</td>

<td>% MMAN</td><td>14.0</td><td>14.0</td><td>14.0</td><td>14.0</td><td>14.0</td><td>14.0</td><td>14.0</td><td>14.0</td><td>14.0</td>

<td>Crystallization temperature (° C)</td><td>6</td><td>1</td><td>-2</td><td>11</td><td>20</td><td>11</td><td>7</td><td>9</td><td>11</td>

[0041] In Table 8 below, we present results for solutions made with identical amounts of water and MMAN, but in the absence of magnesium nitrate.

Table 8:

<td>Mix number</td><td>E1 *</td><td>E2 *</td><td>E3</td><td>E4</td><td>E5</td><td>E6 *</td><td>E7 *</td><td>E8 *</td>

<td>% AN</td><td>7.3</td><td>13.2</td><td>18.1</td><td>22.1</td><td>25.6</td><td>28.5</td><td>31.1</td><td>33.3</td>

<td>% CN</td><td>60.2</td><td>54.3</td><td>49.4</td><td>45.4</td><td>41.9</td><td>39.0</td><td>36.4</td><td>34.2</td>

<td>Moli AN / moles of CN</td><td>0.25</td><td>0.50</td><td>0.75</td><td>1.00</td><td>1.25</td><td>1.50</td><td>1.75</td><td>2.00</td>

<td>% water</td><td>18.5</td><td>18.5</td><td>18.5</td><td>18.5</td><td>18.5</td><td>18.5</td><td>18.5</td><td>18.5</td>

<td>% MMAN</td><td>14.0</td><td>14.0</td><td>14.0</td><td>14.0</td><td>14.0</td><td>14.0</td><td>14.0</td><td>14.0</td>

<td>Crystallization temperature (° C)</td><td>6</td><td>4</td><td>-3</td><td>-7</td><td>7</td><td>14</td><td>18</td><td>22</td>

[0042] This shows that at relatively low magnesium nitrate concentrations, with a molar ratio of calcium nitrate to magnesium nitrate of about 4.5: 1 or more, a crystallization temperature below zero can still be obtained, provided that the molar ratio of ammonium nitrate to the sum of calcium nitrate and magnesium is about 1: 1. It is obvious that when there is magnesium nitrate, the molar ratio is between ammonium nitrate and the sum of calcium and magnesium nitrates, and not between ammonium nitrate and the same

EP 2 812 295 with calcium nitrate.

[0043] Solutions with different amounts of sodium nitrate (SN) were then prepared with the same amounts of monomethylammonium nitrate and water as used in blends A1 to A8 in Table 1 above, but now without calcium nitrate. The results are shown in Table 9 below:

Table 9:

<td>Mix number</td><td>SN1 *</td><td>SN2 *</td><td>SN3 *</td><td>SN4 *</td><td>SNS *</td><td>SNS *</td><td>* SN7</td><td>SN8 *</td><td>SN9 *</td><td>SN10 *</td>

<td>% AN</td><td>61</td><td>59</td><td>57</td><td>55</td><td>53</td><td>51</td><td>49</td><td>47</td><td>45</td><td>43</td>

<td>% SN</td><td>0</td><td>2</td><td>4</td><td>6</td><td>8</td><td>10</td><td>12</td><td>14</td><td>16</td><td>18</td>

<td>Moli AN / moles SN</td><td>-</td><td>31.3</td><td>15.1</td><td>9.7</td><td>7.0</td><td>5.4</td><td>4.3</td><td>3.6</td><td>3.0</td><td>2.5</td>

<td>% water</td><td>22.0</td><td>22.0</td><td>22.0</td><td>22.0</td><td>22.0</td><td>22.0</td><td>22.0</td><td>22.0</td><td>22.0</td><td>22.0</td>

<td>% MMAN</td><td>17.0</td><td>17.0</td><td>17.0</td><td>17.0</td><td>17.0</td><td>17.0</td><td>17.0</td><td>17.0</td><td>17.0</td><td>17.0</td>

<td>Crystallization temperature (° C)</td><td>35</td><td>33</td><td>32</td><td>31</td><td>thirty</td><td>thirty</td><td>31</td><td>thirty</td><td>33</td><td>47</td>

[0044] It is clearly visible that although there is a small effect of decreasing the crystallization temperature when adding sodium nitrate to about 16%, this effect is almost negligible compared to a system containing only ammonium nitrate, monomethylammonium nitrate and water, as opposed to a system in which Calcium nitrate is used, where the drop in the crystallization temperature is drastic when the molar ratio of ammonium nitrate to calcium nitrate is close to 1: 1.

[0045] Solutions were prepared with sodium nitrate (SN) together with calcium nitrate, ammonium nitrate, monomethylammonium nitrate and water. The results are shown in Table 10 below.

Table 10:

<td>Mix number</td><td>P1 *</td><td>P2 *</td><td>P3 *</td><td>P4 *</td><td>P5 *</td><td>P6 *</td><td>P7 *</td><td>P8 *</td><td>P9 *</td><td>P10 *</td>

<td>% AN</td><td>14.6</td><td>20.0</td><td>24.6</td><td>28.4</td><td>31.7</td><td>14.2</td><td>19.4</td><td>23.8</td><td>27.5</td><td>30.7</td>

<td>% CN</td><td>44.9</td><td>39.5</td><td>34.9</td><td>31.1</td><td>27.8</td><td>47.8</td><td>42.6</td><td>38.2</td><td>34.5</td><td>31.3</td>

<td>% SN</td><td>8</td><td>8</td><td>8</td><td>8</td><td>8</td><td>5.5</td><td>5.5</td><td>5.5</td><td>5.5</td><td>5.5</td>

<td>Moli AN / moles of CN</td><td>0.67</td><td>1.04</td><td>1.44</td><td>1.87</td><td>2.34</td><td>0.61</td><td>0.93</td><td>1.28</td><td>1.63</td><td>2.01</td>

<td>% water</td><td>18.5</td><td>18.5</td><td>18.5</td><td>18.5</td><td>18.5</td><td>18.5</td><td>18.5</td><td>18.5</td><td>18.5</td><td>18.5</td>

<td>% MMAN</td><td>14.0</td><td>14.0</td><td>14.0</td><td>14.0</td><td>14.0</td><td>14.0</td><td>14.0</td><td>14.0</td><td>14.0</td><td>14.0</td>

<td>Crystallization temperature (° C)</td><td>25</td><td>19</td><td>16</td><td>18</td><td>20</td><td>6</td><td>5</td><td>-1</td><td>9</td><td>16</td>

[0046] It is evident that in the presence of sodium nitrate, if only the molar ratio of ammonium nitrate to calcium nitrate falls within the range given for the system without sodium nitrate, small amounts of sodium nitrate may be introduced, but even at these low levels it has the effect of increasing crystallization temperatures. A similar effect can be observed for potassium nitrate, as shown in Table 11 a and Table 11 b below:

Table 11 a:

<td>Mix number</td><td>KN1 *</td><td>KN2 *</td><td>KN3 *</td><td>KN4 *</td><td>KN5 *</td><td>KN6 *</td><td>KN7 *</td><td>KN8 *</td><td>KN9 *</td><td>KN10 *</td>

<td>% AN</td><td>14.4</td><td>15.5</td><td>19.6</td><td>24.1</td><td>27.8</td><td>31.0</td><td>14.0</td><td>16.4</td><td>19.2</td><td>23.5</td>

<td>% CN</td><td>43.6</td><td>42.5</td><td>38.4</td><td>33.9</td><td>30.2</td><td>27.0</td><td>47.0</td><td>44.6</td><td>41.8</td><td>37.5</td>

<td>% Potassium nitrate</td><td>9.5</td><td>9.5</td><td>9.5</td><td>9.5</td><td>9.5</td><td>9.5</td><td>6.5</td><td>6.5</td><td>6.5</td><td>6.5</td>

<td>Moli AN / moles of CN</td><td>0.68</td><td>0.75</td><td>1.05</td><td>1.46</td><td>1.89</td><td>2.35</td><td>0.61</td><td>0.75</td><td>0.94</td><td>1.28</td>

<td>% water</td><td>18.5</td><td>18.5</td><td>18.5</td><td>18.5</td><td>18.5</td><td>18.5</td><td>18.5</td><td>18.5</td><td>18.5</td><td>18.5</td>

<td>% MMAN</td><td>14.0</td><td>14.0</td><td>14.0</td><td>14.0</td><td>14.0</td><td>14.0</td><td>14.0</td><td>14.0</td><td>14.0</td><td>14.0</td>

<td>Crystallization temperature (° C)</td><td>0</td><td>&lt;-6</td><td>-4</td><td>2</td><td>12</td><td>21</td><td>1</td><td>&lt;-6</td><td>&lt;-6</td><td>-3</td>

EP 2 812 295

Table 11 b:

<td>Mix number</td><td>KN11 *</td><td>KN12 *</td><td>KN13 *</td><td>KN14 *</td><td>KN15 *</td><td>KN16 *</td><td>KN17 *</td><td>KN18 *</td><td>KN19 *</td>

<td>% AN</td><td>27.1</td><td>30.2</td><td>14.0</td><td>15.0</td><td>17.1</td><td>20.6</td><td>25.2</td><td>29.1</td><td>32.5</td>

<td>% CN</td><td>33.9</td><td>30.8</td><td>38.3</td><td>37.3</td><td>35.2</td><td>31.7</td><td>27.1</td><td>23.3</td><td>19.8</td>

<td>% Potassium nitrate</td><td>6.5</td><td>6.5</td><td>15.2</td><td>15.2</td><td>15.2</td><td>15.2</td><td>15.2</td><td>15.2</td><td>15.2</td>

<td>Moli AN / moles of CN</td><td>1.64</td><td>2.01</td><td>0.75</td><td>0.82</td><td>1.00</td><td>1.33</td><td>1.91</td><td>2.57</td><td>3.36</td>

<td>% water</td><td>18.5</td><td>18.5</td><td>18.5</td><td>18.5</td><td>18.5</td><td>18.5</td><td>18.5</td><td>18.5</td><td>18.5</td>

<td>% MMAN</td><td>14.0</td><td>14.0</td><td>14.0</td><td>14.0</td><td>14.0</td><td>14.0</td><td>14.0</td><td>14.0</td><td>14.0</td>

<td>Crystallization temperature (° C)</td><td>8</td><td>18</td><td>12</td><td>10</td><td>11</td><td>20</td><td>26</td><td>32</td><td>36</td>

[0047] The emulsion products were then prepared from solutions B4 and K3 to test their effectiveness as an explosive. These two solutions were chosen because they both crystallized at -4 ° C and both contain the same amount of water, but different amounts of monomethylammonium nitrate, to check the effect of monomethylammonium nitrate on the explosive properties of the resulting explosive as an emulsion. The final products had the following analysis results.

Table 12:

<td>Mix number</td><td>Emulsion B4</td><td>K3 Emulsion *</td>

<td>% AN</td><td>18.9%</td><td>21.6%</td>

<td>% CN</td><td>38.8%</td><td>44.2%</td>

<td>% MMAN</td><td>12.6%</td><td>2.9%</td>

<td>% water</td><td>19.8%</td><td>19.4%</td>

<td>PIBSA emulsifier</td><td>1.0%</td><td>1.0%</td>

<td>Soybean oil</td><td>5.8%</td><td>7.8%</td>

<td>Glass microspheres *</td><td>3.1%</td><td>3.1%</td>

<td>Oxygen for balancing</td><td>-0.75%</td><td>-0.04%</td>

<td>Theoretical energy of an explosive</td><td>2.874 MJ / kg</td><td>2.950 MJ / kg</td>

<td>Density of the product</td><td>1.19 g / cm3</td><td>1.19 g / cm3</td>

<td colspan="3">* K20 microspheres manufactured by 3M</td>

[0048] Emulsions were enclosed in covers with a diameter of 50 mm, length 600 mm, by insertion into a plastic tubular film (thickness 100 microns) and 15 g of a pentolite detonator was initiated. Emulsion B4 was initiated and exploded along its entire length at a constant rate, as demonstrated by the use of a pipette placed in contact with the charge, which has completely flattened over the full length of the load. The K3 emulsion did not cause an explosion and most of the product was recovered. This test indicates that monomethylammonium nitrate not only improves the salt solubility at gradually lower water levels, but also promotes the sensitivity of the final emulsion.

[0049] The invention opens up by transporting an aqueous oxidant solution, an oil mixture and an emulsifier and a gassing reagent separately to the mine and then transporting them from the surface to the underground work site through relatively small diameter pipelines of any desired length directly to the face in order to detonating them, and then only mixing the three liquids (oxidant solution, oil / emulsifier solution and gassing reagent) to form the explosive as an emulsion after they are pumped into the bore. It may also be acceptable to emulsify the gassing reagent in the oil / emulsifier mixture and thereby transport only two liquids under the ground to be mixed at the frontal detonation site. It is important

EP 2 812 295