Meal powder is the fine dust left over when black powder (

gunpowder Gunpowder, also commonly known as black powder to distinguish it from modern smokeless powder, is the earliest known chemical explosive. It consists of a mixture of sulfur, carbon (in the form of charcoal) and potassium nitrate (saltpeter). Th ...

) is corned and screened to separate it into different grain sizes. It is used extensively in various

pyrotechnic Pyrotechnics is the science and craft of creating such things as fireworks, safety matches, oxygen candles, explosive bolts and other fasteners, parts of automotive airbags, as well as gas-pressure blasting in mining, quarrying, and demolition. ...

procedures, usually to prime other compositions. It can also be used in many

fireworks Fireworks are a class of low explosive pyrotechnic devices used for aesthetic and entertainment purposes. They are most commonly used in fireworks displays (also called a fireworks show or pyrotechnics), combining a large number of devices ...

to add power and substantially increasing the height of the firework. The powder has occasionally been used as a synonym for Serpentine powder, which it physically resembles. 'Mill meal' powder is a mixture of

potassium nitrate Potassium nitrate is a chemical compound with the chemical formula . This alkali metal nitrate salt is also known as Indian saltpetre (large deposits of which were historically mined in India). It is an ionic salt of potassium ions K+ and nitr ...

, charcoal and sulfur in the correct proportions (75% potassium nitrate:15% charcoal:10% sulfur) which has been ball-milled to mix it intimately. It is used in the same way as commercial meal powder or can be pressed and corned to produce true black powder. Meal powder is made by mixing the ingredients by mass, rather than volume. These ingredients are processed in a ball mill, basically a spinning drum with non-sparking ceramic or lead balls. The more time spent in the mill, the more effective the powder will be. One main reason to ball mill as opposed to other methods is because it presses sulfur and KNO₃ into the porous charcoal.

References

Pyrotechnic compositions Gunpowder de:Schwarzpulver#Mehlpulver {{explosive-stub