The operation of the illantuls proeess at Jerez Lanteira is thus described by Sefior Sanchez Nassia, who is in charge of the works there: The carriage runs on rails placed at a level 5 ft. lower than the floor of the blast-furnace in which the matte is made, and on being brought in front of the same the han dle, Al, is turned, and the Convertor is inclined so as to allow the matte to run into it. When the charge is in the converter this is raised to a vertical posi tion, and is carried tinder the ehimney for the outlet of the gases and fumes, and after being thus placed the air-chamber is connected with the air-main. The air is then admitted, and the converter inclined so that the air may enter and go the charge at a convenient depth. This depth varies with the quality and composition of the matte treated. and may also vary at different stages of tho operation.
The blast oxidizes the sulphur, arsenic, and antimony, and these pass to the chimney, while the non-volatile impurities are also oxidized and combine with the silica of the lining. Some times silica is added to the charge, by which means the lining is made to last longer. Usual ly a lining lasts for 24 hours. and for continual work three converters should be kept, which is easy enough, us the cost of each is only about *500. Should the slag be in excess, the blow ing is stopped and the converter inclined to let out a part of it ; then the converter is brought to its proper position and the blowing continued. During the operation a man is kept con tinually at work to clear the tuye'res, and, as particles of slag and matte are expelled from the converter. the men in attcmlance are protected by a kind of horizontal mnbrella of iron fixed on their :shoulders. The end of the operation is recognized by the intense green color of the flame, which indicates that some copper is being burned. At this stage the blowing is stopped, the converter inclined. the slag raked out, and the copper run into ingot-molds.
Whatever may be the quality of the matte acted upon, success can always be attained, since this depends upon the depth at which the charge is blown. This depth can always lie regulated by the inclination of the converter. The weight of the charge may vary within wide limits, but at derez-Lanteira it is usually one ton. The time employed in treating each charge varies from 20 to 4(1 minutes, according to the yield of the matte, the shortest time, being for the richest matte. The heat left by one, charge ill the converter is enough for the next, and therefore, whew the working of the converter does not keep pace with the smelting of the (nes, it is better to stare the excess of matte and remelt it again. The amount of coke
used for smelting is 8 per cent. of the weight of the matte. The slag always contains sonic copper, and for this reason it is usually sent back to he passed through the cupola. The fumes from the converter are made to puss through a gallery 55 in, in length, with the object of collecting some of the antimony contained in the ores.
When the :NI anli6s system 14 dealing wit h copper mattes is compared with the usual method, it very great economy of fuel is (+dined. Al .Terez-liantchw. where water-power is used for the blowing-engiurs, the fuel consumed is only one seventh or what would be required in the usual method. The mattes from which the best results are obtained are those containing 20 per cent iron and 25 per cent sulphr. The air is injected at a pressure of half an atmosphere, or, say, 71 lbs. per sq. in. This proces; has been introduced at the works of the Parrot Silver and ('upper Co., at But to, :Mout_ with very good results.
Works for referencr.; Modern American _Methods of ('opper-Smelling. by I). Peters, Jr., 18111 ; Copper-Smelling, Iry 11. M. Howe; Copper-Smelling. its History and i'roresses, by II, II. Vivian. Issl ; Efenients of Metallurgy, by .1..1. Phillips. Introdnelion hr Me Shuhl of by W. Roberts-Austen, Isill : The Nines and Iteduction Works of Mlle, Nom., by E. D. Peters, .1r_ Mineral llesouree.s e)1 /he United Stoles. 1555: Copper Re liuin the Cnitvd Slates, hy EglesInn. Tronsortions Amerleon In.steinte Mining Engi neers, vol. ; The Ilasic Process applied to Copper-Smelting, by Perey C. Gilchrist. .lonrnol of the Nudely of Chem holuslry, January. 180 : The Ilessenwriz ng of Copper ,Mattes. by .School ymtrlerly, Nay, Iss5; Lead Slags, by 31. W (les, -1/inertti Resources of the United States, 1883 and 1884; Lead-Smelting, by 0. II. Hahn, .31 ineral Re sources of the United Stales, 1886; The Desilverization of Lead, by II. 0. Ilofmann, Mineral Resources of the United States, 1887.
Fuse: see Torpedo.
Gadding: see Quarrying-Machines.
Graining is grooving at right angles to the fiber of the wood, or, more properly, to the length of the stick or plank ; and it may be done by routing-tools, cutting both with their ends and with their sides, making a channel by reason of the tool and the timber having relative motion to each other at right angles to the length of the stick ; or by saws or cutters mounted on an axis parallel with the face of the timber, and working the groove with their peripheral cutters ; or by a saw having a wobbling motion by reason of being set at an angle to an axis parallel with the face and length of the piece.