For information about burning lime we republish the following article furnished by a correspondent of the Country Gentleman several years ago:
Fig. 2. Fig. 3.
A (Fig. 1), Railway Track--B B B, Iron Rods running
through Kiln--C, Capstone over Arch--D, Arch--E,
Well without brick or ash lining.
I send you a description and sketch of a lime-kiln put up on my premises about five years ago. The dimensions of this kiln are 13 feet square by 25 feet high from foundation, and its capacity 100 bushels in 24 hours. It was constructed of the limestone quarried on the spot. It has round iron rods (shown in sketch) passing through, with iron plates fastened to the ends as clamps to make it more firm; the pair nearest the top should be not less than 2 feet from that point, the others interspersed about 2 feet apart--the greatest strain being near the top. The arch should be 7 feet high by 5½ wide in front, with a gather on the top and sides of about 1 foot, with plank floor; and if this has a little incline it will facilitate shoveling the lime when drawn. The arch should have a strong capstone; also one immediately under the well of the kiln, with a hole 2 feet in diameter to draw the lime through; or two may be used with semicircle cut in each. Iron bars 2 inches wide by 1/8 inch thick are used in this kiln for closing it, working in slots fastened to capstone. These slots must be put in before the caps are laid. When it is desired to draw lime, these bars may be pushed laterally in the slots, or drawn out entirely, according to circumstances; 3 bars will be enough.
The slots are made of iron bars 1½ inches wide, with ends rounded and turned up, and inserted in holes drilled through capstone and keyed above.
The well of the kiln is lined with fire-brick one course thick, with a stratum of coal ashes three inches thick tamped in between the brick and wall, which proves a great protection to the wall. About 2,000 fire-bricks were used. The proprietors of this kiln say about one-half the lower part of the well might have been lined with a first quality of common brick and saved some expense and been just as good. The form of the well shown in Fig. 3 is 7 feet in diameter in the bilge, exclusive of the lining of brick and ashes. Experiments in this vicinity have proved this to be the best, this contraction toward the top being absolutely necessary, the expansion of the stone by the heat is so great that the lime cannot be drawn from perpendicular walls, as was demonstrated in one instance near here, where a kiln was built on that principle. The kiln, of course, is for coal, and our stone requires about three-quarters of a ton per 100 bushels of lime, but this, I am told, varies according to quality, some requiring more than others; the quantity can best be determined by experimenting; also the regulation of the heat--if too great it will cause the stones to melt or run together as it were, or, if too little, they will not be properly burned.
The business requires skill and judgment to run it successfully.
This kiln is located at the foot of a steep bluff, the top about level with the top of the kiln, with railway track built of wooden sleepers, with light iron bars, running from the bluff to the top of the kiln, and a hand-car makes it very convenient filling the kiln. Such a location should be had if possible. Your inquirer may perhaps get some ideas of the principles of a kiln for using coal. The dimensions may be reduced, if desired. If for wood, the arch would have to be formed for that, and the height of kiln reduced.