Crude Naphthalene from Light Creosote Oil: Warnes, 1913

Use washed light creosote, quite free from tarry matter. Pump it into crystallising boilers and let it stand for several days, on average 3 to 5 depending on the time of year, while the naphthalene, the "salts", crystallises out. Then drain the separated oil away through the drain pipes.

Melt the crude naphthalene left in the boilers with closed steam. When it is all liquid and well above its crystallising point, pump it into the recrystallising tanks, and at once blow steam through the pipes so no liquid salts set solid in them. Let it cool and recrystallise from the oil carried over.

After two to four days open the drain taps and run off the oil that has separated. When the crude naphthalene has thoroughly drained, it can be packed in barrels as drained naphthalene.

For pressed naphthalene, fill press bags (sometimes ordinary sacking) with the recrystallised crude, about 9 by 18 by 3 inches, keeping them evenly thick. Lay them on the press table about 2 inches apart, cover with a wrought-iron plate about 1/4 inch thick, and build up layer on layer, each lying squarely over the one below. Raise the press gently, then slowly increase the pressure to 1 1/2 to 2 tons per square inch and hold about an hour.

Release the pressure and take the cakes from the bags. Cut off any wet edges and press them again with the next batch. Break the cakes up in a disintegrator and pack them.