6a. Methods of forming pyrotechnic compositions

In some cases, the desired pyrotechnic composition can be readily formed by simply blending the ingredients together using any desired means. However, sometimes pyrotechnic compositions can only be formed when they are mixed in special ways. Black powder for example, cannot simply be made by just blending the ingredients together. To form black powder and similar pyrotechnic mixtures, the ingredients of the mixtures need to be blended very thoroughly to form a uniform mix; solvents are also widely used to facilitate proper blending to maximize surface area. To mix these ingredients very thoroughly requires special mixing devices. There are two main types of mixing apparatus available. The most common is the “ball mill”, and “vertical mixer”. A ball mill is a simple device utilizing a central container, similar to an empty coffee can laying on its side, and a small electric motor. The electric motor rotates the coffee can utilizing a fan belt or similar band. The rotating speed can very from 50 to 1500 RPM, depending on the type of mixing desired. In some cases, steel balls, or other materials are added to the mill, so they produce a high surface area of blending and pulverizing when the can rotates. Ball mills are one of the most common apparatus used to form pyrotechnic compositions, such as black powder. Also, as mentioned, in other cases, an inert solvent is added to facilitate proper pulverization and coheasion with maximum surface area. The second most common type of mixer is a vertical mixer. There are two types of “vertical mixers”; a) a common blender, as found in your kitchen, using stainless steel blades, and b) a large capacity “vertical mixer” utilizing plastic or stainless steel pallet blades that rotate widely and at a uniform speed; similar to a bread blender you might have in your home. All ingredients are added when necessary, and the mixture can be dry blended, or “wet” blended using an inert solvent to facilitate maximum surface area. Now, these two types of mixers may have different names, but their method of work is the same. You can find out more about these mixing devices by conducting a search on the Internet.

04-01-031A: Classic high performance ammonium perchlorate rocket propellant:

05-03-007A: High performance sodium azide containing specialty gun propellant:

06-01-006A: Blue tracer composition with gray smoke trail:

06-01-007A: High visibility tracer composition:

Into a standard ball mill, filled with 500 grams of Teflon coated steel shot of 10mm diameter, place 140 grams of calcium resinate, followed by 60 grams of standard powdered aluminum, followed by 170 grams of standard powdered magnesium, followed by 50 grams of strontium oxalate, followed by 500 grams of strontium nitrate, followed by 40 grams of sodium nitrate, followed by 50 grams of mercurous chloride. Thereafter, rotate the mixture at 170 RPM for 5 hours. After 5 hours, remove the mixture from the ball mill, and then separate the mixture from the steel shot in the usual manner. Thereafter, the mixture is ready for pressing. To do so, press the mixture into the tracer compartment of the given projectile under a pressure of 10,000 psi. Burn rate (tracer burn out, standard 40mm grenade round on average): 50 meters Burn rate (tracer burn out, standard 7.62mm rifle bullet on average): 300 meters Burn rate (tracer burn out, standard 7.62mm machine gun round on average): 600 meters Burn rate (tracer burn out, standard 12.7mm rifle bullet on average): 1200 meters Burn rate (tracer burn out, standard 25mm cannon round on average): 1050 meters Burn rate (tracer burn out, standard 105mm tank fired projectile on average): 1900 meters Water resistance: Good. Stability: Can be stored for many years. Flammability (1 to 10): 4.2 (pressed at 10,000 psi); 5 powdered. Ease of ignition (1 to 10): 4 (pressed at 10,000 psi); 7.9 powdered. Tendency to cake: None. Explosive ability: Cannot be detonated. Percentage: 49.5% strontium nitrate, 16.8% magnesium, 13.8% calcium resinate, 5.9% aluminum, 4.9% strontium oxalate, 4.9% mercurous chloride, 3.9% sodium nitrate, 0.30% residue Classification: Deflagrating mixture (classified as 1.3G pyrotechnic composition).

06-04-045B: Classic highly insensitive ignition composition for use in moderately accelerating projectiles such as mortar rounds:

Into a standard ball mill, filled with 500 grams of steel shot of 10mm diameter, place 350 grams of finely ground magnesium powder of average mesh, followed by 75 grams of potassium perchlorate, followed by 37.5 grams of silicon dioxide and then followed by 37.5 grams of polybutadiene. Thereafter, tumble the mixture at room temperature at 260 RPM for about 45 minutes. Thereafter, the mixture should be removed from the ball mill, and the steel shot separated; thereafter, the mixture is ready for pressing. To do so, press the mixture into blocks, discs, or tablets under a pressure of 2,500 psi. Burn rate: 19 seconds per inch at 2,500 psi; tends to vary based on diameter and density of grain. Burn temperature: 1,260 Celsius. Ignition temperature (average temperature to ignite mixture): 955~ Celsius. Water resistance: Very good. Stability: Can be stored for many years. Flammability (pressed grain at 2,500 psi): 5.68 Ease of ignition (average temperature to ignite mixture): 6.2 Tendency to cake: None. Explosive ability: Cannot be detonated. Percentage: 70% magnesium, 15% potassium perchlorate, 7.5% silicon dioxide, 7.5% polybutadiene Classification: Deflagrating mixture (classified as 1.3G pyrotechnic composition).