SE452761B - Phlegmatisation of crystalline explosives and plastic explosive prodn. - Google Patents

Abstract

In the phlegmatisation of crystalline explosives, e.g. octagen, hexagon or PETN, or combinations with partic. non-explosives, e.g. powdered Al, by wet granulation with water, a minor proportion of the phlegmatisation or binder agent is replaced by oxazolin wax. The wax is dissolved in a solvent (e.g. trichloroethane or methyl chloroform) and agitated with the granulation suspension at which time the solvent is driven off. This causes the wax to be deposited on the particle surfaces before the phlegmatisation agent proper or the binder is added and deposited by continued agitation and temp. regulation of the suspension. Pref. amt. of oxazolin wax is 0.01-0.1% on wt. of solid particulates. Process is also useful before coating with plastics binders.

Description

452 761 2 As already mentioned, there are military specifications that require that octogen and hexogen already as bulk goods must be phlegmatized with a wax that meets certain requirements. There are several for this purpose used wax types of which may be mentioned Wax Composition 1 and D2 but also other waxes can thus be considered. The phlegmatization of octogen and hexogen normally takes place as wet granulation in water where the wax is charged to the water bath whose temperature is raised until everything wax melted after which the water temperature is gradually lowered so that the wax precipitates on the explosive crystals. An even distribution of the phlegmatizer over the crystals is obtained by a suitable stirring_ and temperature control of the granulation suspension. IN to a certain extent, one can thereby also control the size of those obtained the granules. in Now, however, it is common knowledge among those skilled in the art that it often is can be difficult to produce uniformly evenly phlegmatized granules of explosives mentioned here because the wax does not want to spread well enough on the crystal surfaces and has a strong tendency to form larger and smaller flocks with the particulate matter na. The flocculation tendencies of the wax become particularly troublesome during the position of octonal and hexotonal where the wax mainly causes flocculation of the aluminum explosives contained in these blasting explosives the powder.

We have now found a method to eliminate to a very large extent these flocking tendencies both during the granulation itself and at any subsequent remelting of the granulated blast furnace the subject. According to the invention, the explosive crystals are thus coated initially with an oxazoline wax which in turn is covered by it the actual phlegmatizer, for example in the form of a wax of the type required by applicable military specifications. Oxazoline wax is a double unsaturated heterocyclic compound derived from nitropar veneer. It has a melting point of 160 ° C and a molecular weight of 1351352.

Current trade name is Oxazolin wax TX2.

The amount of Oxazoline wax initially added may vary but should be sufficient to coat the individual crystals. Oxazo- the flax wax is thus added in an initial wet granulation step dissolved in a suitable solvent, such as trichlorethylene or chloro- to the crystalline explosive suspended in a mixture of water the substance and any solid particulate likewise suspended therein m, 3 452 761 substance in the form of aluminum powder or equivalent after which the temperature of the mixing water is raised with stirring to or slightly above the boiling point of the solvent and kept there until all solvent is evaporated off whereby the ogazoline wax is gradually precipitated out on the solid particles. Then the real thing is added the phlegmatizer in the form of eg wax composition 1 or type D2. As a rule, a further temperature increase is then required for melting of the phlegmatizer followed by mixing water temperature under suitable mixing is gradually lowered for precipitation. of the phlegmatizer on top of the oxazoline wax.

Such pre-treatment with oxazoline wax has been shown to facilitate phlegmatization and provide a smoother granulation while they the previously mentioned flocking tendencies are suppressed. This applies both for pure granulated explosives and for mixed products of type hexotonal and octonal.

The invention is defined in the appended claims and will now be described in some further detail in connection with the following pel.

EXAMPLE 1 To a reaction vessel equipped with a mechanical stirrer and equipped with heat exchanger arranged for heating and cooling was charged with stirring (100-150 rpm) 150 liters of water and 47.5 kg of octogen whose average particle diameter was 170 μm particle size was between 100 and 300 μm and 0.04% oxazoline wax TX2 dissolved in chlorotene (oxazoline wax content calculated on explosive the amount). The water temperature was raised to 95 ° C and below in turn, the chlorotene was evaporated off and the oxazoline wax precipitated on the crystalline explosive. Then the chlorotene is stripped off and intended temperature was obtained, 2.5 kg of phlegmatizing wax was added ( composition 1) and the batch was kept at a constant temperature below 10 minutes. Then it was cooled and dropped on nutsch. As The result was a homogeneous product with the phlegmatization wax evenly distributed over the crystal surfaces. The grain size distribution on the The product also became narrower than it would have been corresponding product produced without oxazoline wax. With oxozoline wax As mentioned earlier, a more even distribution of phlegmatization the agent over the various particles and thereby avoids the formation of such coarser particles which to a large extent consist only of wax. 452 761 4 The even phlegmatization is very important if the product is to pressed into a compact body which, for example, is relevant in position of initials Q äy1_ In this case, the obtained particles the average particle size of the larvae is about 350 Pm.

EXAMPLES 2 AND 3 Corresponding examples were also carried out under similar conditions with hexogenic respective pentyl of essentially the same average particle size. size and with corresponding results.

Claims (3)

452 761 PATENT REQUIREMENTS A method of phlegmatizing crystalline explosive substances, such as octogen, hexogen and pentyl or mixtures in which such explosive substances are present together with one or more other solid particulate but non-explosive substances such as aluminum powder or the like, by wet granulating and coating the particles with a phlegmatizing and binding agent, of a type known per se, for example in the form of a wax, in water, characterized in that oxazoline wax in a sufficient amount to precisely cover the particles is charged to the granulation suspension (those suspended in the water solids) dissolved in a solvent such as trichlorethylene or chlorotene (methyl chloroform) after which the solvent is evaporated off with continuous mixing of the granulation suspension so that the oxazoline wax is precipitated on the particulate surfaces after which the phlegmatizing binder is caused to precipitate on top of the oxazoline wax and give a comprehensive layer. 2. A method according to claim 1, characterized in that the oxazoline wax is added to an amount corresponding to 0.01 - 0.1% by weight based on solid particulate matter. Phlegmatized crystalline explosive substances prepared in accordance with the method according to claim 1 or 2, characterized in that crystals and / or other solid particles contained therein are coated with a thin inner coating of oxazoline wax which in turn is surrounded by a outer full-covering layer of a phlegmatizer or binder, for example in the form of a wax or a plastic.