All three of the raw materials need purifying and processing before they could be used for gunpowder.
Originally extracted from pigeon dropings and other nitrogen rich manures it was later obtained from imported mineral deposits - mainly India in the 19th century.
The raw saltpetre was disolved in water, boiled and then recrystalised.
Originally the charcoal was made in the traditional way in earth covered mounds. In the late 18th century it was found that putting the wood in sealed iron cylinders and heating these in a furnace produced a far more reliable and effective gunpowder.
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Mixing
All three ingredients were crusehed into a fine powder in a ball mill. They were then mixed in the proportions required for the particular way in which the finished gunpowder was to be used.
Incorporation
Just mixing the ingredients will give a very rapid bugning material, but for an explosive mix every grain must be a mixture of all three of the
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Pressing
Pressing compacted the size of the grains. It gave a stonger explosion for a given weight of gunpowder.
This was the most dangerous stage of production.
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Corning
The cake from either the mill or the press was broken up and the grains were then seived to ensure the final product was of the required grain size. Dust was removed by tumbling in silk walled drums.
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Glazing
This was an optional process only done to powder for certain uses. Graphite dust was added to the gunpowder and tumbled in a drum. The grains of gunpowder ended up with a thin coating of graphite giving it a polished appearance.
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Moulding
Introduced for very large guns and later blasting charges the dry powder was formed in hexagonal prisms or cylinders in hydraulic presses.
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Packing
Formimg into charges or packs for dispatch. Lose powder was packed in barrels but later tins were used for small quantaties for civilian retail products.