DE671648C - Safety detonator - Google Patents

Description

In the patent 651 832 it is proposed alkaline substances, such as sodium carbonate or ammonium carbonate, as stabilizers to be used for the mixture of alkali metal nitrite and ammonium salts. sodium It is true that it is not volatile and, in the anhydrous state, capable of being a permanent hydrate to form, however, provides only limited protection against the decomposition of the mixture

because ammonia is released. The occurrence of ammonia vapor is likely to occur the conversion of ammonium chloride and sodium carbonate to sodium chloride and ammonium carbonate be due. Here-

When the water is present, it was previously retained by the anhydrous sodium carbonate was released as water of hydration. Ammonium carbonate makes the mixture sufficiently stable in and of itself, as long as it is present, but it tends to volatilize (evaporation and diffusion). In the patent 651 832 is accordingly also proposed that in addition to the addition of sodium carbonate or ammonium carbonate to the mixture of the charge still an additional one Amount of ammonium carbonate should be added to cover the loss due to volatilization.

According to the present invention, a solid inorganic substance which is sparingly soluble in water and practically does not react with the ammonium salt is used as a stabilizer for the charge. This substance can have a basic character, e.g. B. an oxide of an alkaline earth metal or magnesium or an earth metal or zinc, or it can be a salt of these metals with a weak acid, e.g. A carbonate, or it may be a compound of such a metal capable of reacting with water, e.g. B. a carbide. In general, substances that have a dehydrating effect, such. B. calcium oxide or carbide, preferable.

Calcium hydroxide is relatively subject to in the presence of moisture rapid alternating decomposition with ammonium salts and is therefore even for the purposes of the Invention not suitable, but when using quick lime or calcium carbide, it is by no means essential whether this substance is completely free of calcium hydroxide, although the increased resistance is crucial to the presence of calcium oxide or carbids. Generally suitable for the purpose of the invention are the oxides, carbon

nates or carbides of the alkaline earth metals or the oxides, hydroxides, carbonates and basic carbonates of magnesium and zinc. For cartridges that are used in ordinary Temperatures are to be stored, the magnesium oxide and for cartridges that stored at higher temperatures, the calcium carbide with powerful dehydrating Effect. These stabilizers prevent the mixtures from decomposing at the elevated temperatures at which they decompose as intended should not, if they also have a certain influence on the minimum temperature ■ 5 which the mixture is to bring.

The amount of stabilizing agent is kept of the alkali metal nitrite ammonium salt mixture is generally between 0.5 and below 5 ° / ₀ by weight. The stabilizing agent is expediently first mixed with the alkali metal nitrite in powder form before the ammonium salt is added, but it can optionally also be added during or after the mixing of the other constituents. More than one stabilizer can be used if desired. Some of these, especially the light, powdery ones, such as magnesium oxide, light magnesium carbonate and calcium carbonate, 3 <> have the advantage of simple mixing.

■ adhesive effect that the mixture becomes granular, which makes loading easier. In such cases the mixture will not be strong subject to mechanical action, such as grinding, because otherwise the grains will break turn around.

The stabilizing effect of the substances leaves determine yourself in different ways. So you can z. B. the weight loss of samples determine after storage at different temperatures. Instead, you can use small amounts of the mixture Subject temperature higher than the storage room temperature but lower than that Temperature at which the mixture immediately begins to decompose, whereby one observed the times after which the mixture developed fumes. The one during the storage attempt Numbers gained can be highly dependent on the relative humidity of the Atmosphere, on the type of container and the way in which you charge the outside air suspends, etc., depend. In the number tables, the effectiveness of various stabilizers show, the figures for the various stabilized mixtures per panel were obtained under comparable conditions; however, these conditions are not necessary with those of the examples or those comparable to other panels.

Number board 1

Stabilizers

Weight loss after storage

at ordinary
temperature

at

1.0% magnesium oxide

1,5 ° / ₀ Magnesia

2.0% magnesium oxide

2.0% / ₀ basic magnesium carbonate

1.0 per _cent magnesium oxide and _{1.0 per cent} basic

Magnesium carbonate
2, o ° / ₀ barium carbonate and X ₁ O ⁰ I ₀ basic

Magnesium carbonate
2, o ° / ₀ calcium carbonate .... "..

In the experiments according to number table 1, finely ground sodium nitrite and ammonium chloride were ^{dried separately at 60 to 70 °} C. and then mixed in stoichiometric amounts at room temperature by initially briefly mixing the sodium nitrite with the stabilizing agent and then adding the ammonium chloride, followed by thorough mixing. The finished mixture turned into cartridges of 200 g none in 289 days

none in 197 days
none in 289 days j

0.1 ⁰ Z ₀ in 270 days
none in 270 days

0.1 ⁰ Z ₀ in 333 days
0.14 per cent in 336 days

! .7 ⁰ zo ⁱⁿ 84 days
5, o ° / ₀ in 183 days

2.0 ⁰ Z ₀ in 130 days
5.3 ⁰ Z ₀ in 200 days
5.6 ⁰ Z ₀ in 36 days. 1.2% in 64 days
7.0 ⁰ Z ₀ in 155 days
5.6 per _cent in 70 days

wrapped that have been dipped in wax. The submerged cartridges were stored at ordinary temperature and in a hot storage room at 35 ° C. The indication of none (no weight loss) means that any weight loss was below the possible experimental error. The corresponding figure for 2 ⁰ Zo sodium carbonate at ordinary temperature was 2.1 ° / "in days.

Number board 2

Stabilizers

Basic magnesium carbonate

Calcium carbonate

Calcium carbide

Magnesia

In the tests, the results of which are given in Table 2, were small Samples of stabilized equimolar genes

'5 mix of sodium nitrite and ammonium chloride in unsealed bottles at 40 and 48 ⁰ C stored. The stabilizer content was 20/0 each time.

When trying out the results

aο supplied according to the number table 3, samples were the stabilized equimolecular mixture of sodium nitrite and ammonium chloride, which had a weight of 20 g, placed in glass cooking tubes at room temperature, and these were immersed in a bath of boiling water. The one in the number table The times reported are those from the moment the pipe is immersed in the boiling water until it decomposes rapidly of the content.

Number η table 3

The invention is further demonstrated by the examples below Charges explained in the pressure-resistant cartridge containers of those described in the '651,832 patent Kind of used. Explosive cartridges containing mixtures according to the examples below as a charge, are firedamp proof (in methane-air mixtures) when used as specified will.

Weight loss after storage

at 40 ° G

at 48 ° C

Explosive charge mixture, Time to smoke stabilized with at ioo ° G Not stabilized .... 3 minutes 2 ° / ₀ sodium carbonate 10 mins 2% calcium carbide. 120 minutes ι ° / ₀ calcium carbide .. 30 minutes 2 ⁰ Z ₀ magnesium oxide. 10 mins 2 ° / ₀ calcium oxide ... 11 minutes

example 1

2% magnesium oxide was added to a powdery mixture of sodium nitrite and ammonium chloride in equimolecular amounts. The magnesium oxide was introduced with gentle stirring, 16% in 25 days
15% ⁱⁿ 20 days

in 44 days

18 ° / ₀ in 8 days

18% in 8 days

none in 33 days

13 ° / ₀ in 12 days

the good taking on a fine-grained shape that made it easier to load. After a storage period of 9 weeks at approximately 15 to 20 ^° C., a cartridge with this charge had only lost approximately 10/0 weight. When stored below 35 ° C for 5 weeks, the weight loss was approximately 0.25% and after 10 weeks 0.4%

Example 2

2% calcium carbonate powder was mixed into a powdery mixture of sodium nitrite and ammonium chloride in equimolecular amounts. After 4 weeks storage at 15 to 20 ⁰ C, the weight loss was approximately o, i2 ° / o, and after 5 weeks storage at 35 ° C it was about 4% · The mixture was sufficiently empfindlieh for ignition.

Example 3

A mixture of 2 ° / ₀ Witheritpulver and ι ° / o of powdered basic magnesium carbonate is a powdered mixture of equimolar amounts of sodium nitrite and ammonium chloride. mixed in. After 4 weeks storage at 15 to 20 ⁰ C, the weight loss was about 0.1 ° / ₀ and after 6 weeks storage at 35 ° C it was about 1.7 ° / o. The mixture was still sufficiently sensitive to ignition.

Example 4

A mixture of 2 ° / ₀ magnesium oxide and ι% of basic magnesium carbonate was used instead of only magnesium oxide as in Example. 1 The weight loss after 4 weeks of storage at 15 to 20 ⁰ C was less than ο, τ ° ' _o .

Example 5

The ingredients and amounts were the same as in Example 1, but that Magnesium oxide is first mixed into the powdery sodium nitrite while stirring gently and then continued gentle stirring while introducing the powdered ammonium chloride. The estate received a fine-grained one Shape so that it could trickle freely, which makes it easy to load.

Example 6

Equimolecular amounts of sodium nitrite and ammonium chloride were made with 2% calcium carbide mixed. The calcium carbide was first ground together with the sodium nitrite, and after it was well distributed, the ammonium chloride became a continuation added to the grinding for a certain period of time. The estate then became too Beads shaped to make loading easier.

Claims (3)

Patent claims: i. Safety cartridge according to patent 651 832, characterized in that the Charge small amounts, about 0.5 to 5 percent by weight of the mixture, in order to increase its chemical resistance, of a solid, inorganic substance, hardly soluble in water, which is practical does not react with the ammonium salt in question. 2. explosive cartridge according to claim i, - characterized in that the Stabili- sizing agent has dehydrating properties. 3. explosive cartridge according to claim 1, characterized in that the inorganic Stabilizing agent an oxide, carbonate or carbide of an alkaline earth metal or an oxide, hydroxide, carbonate or basic carbonate of magnesium or zinc.