When iron is tapped from the furnace, it is the practice at present to convey it by means of a trough or trench into a large ladle, even if it is to be cast into pigs. Fig. 16 shows iron flowing along a trench from the furnace, on its way to the ladles, and Fig. 17 shows the metal flowing into ladles. Large ladles hold about 50 tons, and are either supported on a car and hauled by a small locomotive, or are lifted and transported by a traveling crane. The ladle contents may be disposed of in any of the ways below stated, depending upon the purpose for which the smelter product of a particular composition may be suited.

(1) Poured into a large reservoir called a "mixer " which maintains a supply of molten metal (designated as "hot" or "direct" metal) for:

(a) Making steel by the open hearth process.

(b) Making steel by the Bessemer process.

(2) Poured into pig moulds made of heavy iron to be re-melted later for:

(c) Making iron castings in the foundry.

(d) Making wrought iron in the puddling furnace.

(e) Uses stated in items (a) and (b).

Fig. 16. - Base of a Blast Furnace showing iron flowing from the furnace along trenches conveying it to ladles. The stream is directed along the trenches by the gates G. When the flow of iron from the furnace is to be stopped, the "mud gun" H is swung around on its crane R in front of the tapping hole. It operates a piston rod by hydraulic power and forces a cone of clay into the tapping hole.

Fig. 17. - Ladles Receiving Molten Pig Iron from Blast Furnace Troughs.