Page:Encyclopædia Britannica, Ninth Edition, v. 13.djvu/322

 306 IRON &c. In order to diminish the liability to explosions from this effect of water, Lloyd has patented a peculiar tuyere into which the cool ing water is injected in the form of spray or fine jets all over the outer surface of an inner conical tube through which the hot air passes, as well as over the inner surface of an outer covering cone, so that in case of the end of the tuyere being burnt away the volume of water injected into the furnace is much lessened, as owing to the incline backwards of the lowest part of the cone (the axis being horizontal) most of the water runs out aivay from the furnace instead of being forced into it by the pressure of the head of water as in the ordinary coil tuyere. When the water supplied is muddy, or is apt to deposit matter on warming or standing, there is a liability to stopping up of the holes through which the fine jets of water pass; to remedy this Plum modifies the arrangement by mak ing the water pass through a slit or against a sheet of metal so as to spread it out into fan-shaped jets delivered against the nose of the tuyere and the upper half of the outer shell. For drawings of this &quot;spreader tuyere,&quot; see Journal I. and S. Inst., 1878, 299. 1 16. Collection of Cinder and Pig Iron. As the cinder flows off from the furnace ifc is usually received in rectangular or cylindrical iron tanks mounted on wheels and running on a railway at a few feet lower level than the base of the furnace ; the cinder balls thus formed are usually dis charged on to some vacant piece of ground in the vicinity of the furnace, thus entailing the loss of the value of the ground. 2 The Kloman machine used in America for the reception of the cinder consists of a series of iron boxes placed in a water tank on a turn-table, the object being to quicken the solidification of the cinder and get it out of the way more rapidly. In order to cast the pig iron into convenient marketable forms, the ground in front of the tapping hole is made into a pigbed, by arranging it at a gentle slope from the tapping hole and covering it with loam or sand. A channel is dug in this with a spade, &c., leading down the slope in a right line from the tapping hole ; and at right angles to this side channels are dug, the ground sloping laterally away from the main channel ; from each side channel moulds are made to spring, prepared by pressing into the yielding sand wooden blocks some 2 or 3 feet in length, and in section like a capital D, the convex side (on which is embossed or engraved the particular mark or brand of the iron-works) being downw r ards. When the furnacs is tapped the rivulet of molten metal running down the main channel is first directed into the lowest row of moulds, and when these are full the supply is shut off by plunging a spade coated with fireclay into the channel at a (fig. 24), so as to fill up the second row of moulds, and so on successively until only cinder flows out at the tapping hole. Whilst the castings are still at a dull red heat and the metal is consequently Fig. 24. brittle, the ings or masses of metal filling the moulds are detached from the soivs, or irregular larger pigs from the channels, by means of a crowbar. In some works the tap ping is performed only once in twelve hours ; in others a cast is made every eight hours or even more frequently ; of course the oftener the furnace is tapped the less the size of the pigbed required. Occasionally the molten metal is J A large amount of detailed information as to the dimensions and construction arid general working of the blast furnaces and subsidiary plant of a number of the more important American iron-works is to be found in a series of papers on &quot; American Iron and Steel Works,&quot; by A. L. Holley and Lenox Smith, Engineering, 1877, &c. 2 In the vicinity of Middlesborough they have for some time been largely disposed of by using them to build a retaining wall to keep the sea back from low-lying ground and mud banks covered at high water to a greater or lesser extent, whereby not only is a valueless waste product got rid off, but a recovery of what may hereafter prove to be valuable land from the sea is effected. run into waggons lined with firebrick serving as reservoirs supplying with fused pig Bessemer converters conjoined with the smelting furnaces ; so that the molten cast iron is run directly into the converters and finished off without ever solidifying before the completion of the steel-making process. Sometimes the metal is cast into pigs in iron moulds instead of a sand bed. ^Com2)ositionofPigIron. r ?}ie following analyses illustrate the difference in composition of various kinds of pig iron as met with in the market : Pig Irons comparatively free from Sulphur and Phosphorus.

Character of Pig and Locality. ... I Cumberland and Lancashire Hematite Pig. Danne- mora Charcoal Tig, Mag netite. Hisenerz Charcoal Pig, Spathic Ore. Lake Superior Charcoal Iron. Brown Hcematite and Specular Ore, Nova Scotia, No. 1. White- haven, No. 2. Cleator Grey Foundry Analyst Abel. Abel. Henry. Miiller. Snelus. Tookey. Iron 94-86 trace 2-24 2-77 o-oi 0-05 0-07 9394 j- 4-18 1-02 0-05 008 002 95-57 4-20 0-08 trace 0-05 0-10 05-68 0-13 o-oi trace 0-61 03-34 ( 0-38 13-39 2-28 0-03 0-10 0-17 94-85 ) &quot;.r. f 0-84 0-02 0-19 0-44 &quot;Combined&quot; carbon Graphite Silicon Sulphur Phosphorus Manganese 100-00 100-19 100-00 100-00 99-G9 99-84 Pig Irons containing much Sulphur, Phosphonts, Silicon, &amp;lt;&amp;lt;*. f Character of Pig I and Locality.... 1 Cleveland Iron stone, Clarence Furnaces. Calder Works, Foundry Pig. Northamp tonshire Ores mixed with tap- cinder. Arseni cal Pig, White. Glazy Iron, Cleveland. No. 1. Mottled. Analyst |. Pattin- son. Pattin- son. Ber hier. Henry. Mitte- regger. Lowthian Bell. Iron 92-43 0-32 3-43 1-70 0-13 1-24 0-30 0-56 93-59 085 2-70 0-66 0-35 1-05 0-79 02-30 0-40 1-80 2-80 1-40 1-30 92-825 0-186 2-450 2-067 0-320 1-432 0-720 93-39 1-93 055 0-19 0-07 0-04 2-02 1-70 0-11 88-18 0-79 2-59 5-13 0-17 1-12 T 0-26 3-28 &quot;Combined&quot; carbon Graphite Silicon Sulphur Phosphorus Manganese Titanium Arsenic Copper Calcium, Magnes- ium, Alumin- J- ium, &c., j 0-00 100-17 0-33 traces 100-32 100-00 100-000 100-00 99-29 Composition of Cinder. Sometimes cinder is highly crystalline ; that from clay ironstone, especially of the Cleveland district, however, is usually amorphous ; the structure in all cases depends much upon the rate of cooling, a cinder which is distinctly crystalline when a large mass is cooled slowly being often vitreous and wholly devoid of crystalline texture when cooled quickly in Analyses showing Composition of Cinder. Askam in f Locality and Particulars...&quot;! Calcined Cleveland Ore, Hard Coke, and Limestone. Furness, Askam Hiematite and Fisher s Red Bay Cwm Celyn, Scouring Cinder. Olsberg, West phalia, Brown Haematite and Char Edstra, Sweden, Mag netite and Char Eisenerz, Styria, Spathic Ore and Char- Aluminous coal. coal. Ore. Analyst -I Lowthian Bell. Stock. Noad. Rammels- berg. Follier. Wehrle. Silica 27 -(55 38-00 42-96 55-25 58-1 54-6 24-69 10 00 20-20 5-71 5-1 2-6 40-00 42-19 10-19 27-60 18-0 10-4 3-55 1-C5 2-PO 7-01 13-3 1-3 Potash and soda.. 1-45 3-C3 1-10 Ferrous oxide .... 0-72 2-08 19-80 1-27 1-0 i-4 Manganese oxide 0-35 trace 1-53 3-16 4-1 28-6 Calcium sulphide 1-95 2-45 1-32 1-1 Phosphorus 0-26 100-62 100-00 100-00 100-00 99-6 1000 small quantities at a time. Presence of much lime makes the cinder chalky or stony in appearance ; ferrous oxide communicates a dark green or black tint and a ready fusibility to it ; manganese oxide often gives an amethystine shade. Ultramarine appears to be sometimes formed, some slags possessing a blue colour easily dis charged by mineral acids ; the blue tint is, however, attributed by
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