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pig-iron

pig-iron

pig-iron Sentence Examples

  • Pig iron is manufactured cheaply because of the low price of fuel; in 1907 the value of pig iron manufactured in the state was $6,454,000.

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  • These natural advantages make possible the production of pig iron at an unusually low cost.

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  • In 1900 the Birmingham district produced six-sevenths of the total pig iron exported from the United States, and in 1902 nine-tenths of Alabama's coal, coke and pig iron; in 1905 Jefferson county produced 67.5% of the total iron and steel product of the state, and 62.5% of the pig iron produced by the state.

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  • Production of Material and Pig-Iron and Steel.

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  • Some samples of ore, coal and limestone, obtained in the Mittagong district, with pig-iron and castings manufactured therefrom, were exhibited at the Mining Exhibition in London and obtained a first award.

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  • Very little pig iron is tries US made, most of the iron ore being exported, and iron manufactured consists of old iron resmelted.

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  • For steelmaking foreign pig iron is chiefly used.

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  • The production of pig-iron nearly doubled between 1890 and 1900, increasing from 446,800 tons in the former year to 801,600 in the latter; but since 1900 the output has declined, the total for 1904 (inclusive of Siberia) being 644,000 tons.

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  • Out of an average of some 2,700,000 tons of pig-iron produced annually in the whole of the Russian empire, 61.5% is produced in the basin of the Donets, and out of an average of 2,160,500 tons of worked iron and steel 48.7% are prepared in the same region.

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  • Among the manufactures are charcoal, pig-iron, car wheels and general castings at Lime Rock, cutlery at Lakeville, and knife-handles and rubber brushes at Salisbury.

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  • Its railway car repair and construction shops, belonging to the Norfolk & Western railway, employed in that year 66.9% of the total number of factory wage-earners; pig-iron, structural iron, canned goods, bottles, tobacco, planing-mill products and cotton are among the manufactures.

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  • Timber, pig-iron and iron ore are the leading imports, and coal, produce and iron the chief exports.

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  • More than thirty mineral substances are obtained in commercial quantities from the mines, quarries and wells of New York, but of the total value of the mineral products in 1908 ($45,6 6 9, 861), nearly six-sevenths was' represented by clay products ($8,929,224), pig iron ($15,879,000), stone ($6,157,279), cement ($ 2, 2 54,759), salt ($2,136,738), petroleum ($2,071,533), and sand and gravel ($1,349,163).

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  • In the 18th century it ranked next to Leith as a port, but the growth of Grangemouth, higher up the firth, seriously affected its shipping trade, which is, however, yet considerable, coal and pig-iron forming the principal exports, and pit props from the Baltic the leading import.

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  • Their blast furnaces produce 1,700,000 tons of pig-iron annually.

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  • In the manufacture of vehicles, harness, leather, hardwood lumber, wood-working machinery, machine tools, printing ink, soap, pig-iron, malt liquors, whisky, shoes, clothing, cigars and tobacco, furniture, cooperage goods, iron and steel safes and vaults, and pianos, also in the packing of meat, especially pork,' it ranks very high among the cities of the Union.

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  • The yearly production of pig iron a ou had risen to between 500,000 and 600,ooo tons.

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  • Ihe output of pig iron and steel in 1907 was 25,781,361 and 23,362,594 long tons respectively.

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  • Under the stimulus of federal bounties, the production of pig iron and of steel, chiefly from imported ore, is rapidly increasing.

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  • In 1895 it was demonstrated that Alabama pig-iron could be sent to Liverpool and sold cheaper than the English product, and Birmingham (Alabama) came consequently to rank next to Middlesborough and Glasgow among the world centres of the pig-iron trade.

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  • The pig-iron produced in the state in 1860 was valued at $64,590, in 1870 at $210,258, in 1880 at $ 1, 4 0 5,35 6, in 1900 at $13,487,769, and in 1905 at $16,614,577.

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  • In the production of foundry pig-iron Alabama held first rank both in 1900 and in 1905.

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  • Pennsylvania is by far the most important coalproducing state in the Union, and as much of the iron ore of the Lake Superior region is brought to its great bituminous coal-field for rendering into pig-iron, the value of the state's mineral products constitutes a large fraction of the total value for the entire country; in 1907, when the value of the mineral products of the state was $ 6 57,7 8 3,345, or nearly one-third that of all the United States, and in 1908 when the total for the state was $473,083,212, or more than one-fourth that of the whole United States, more than fourfifths of it was represented by coal and pig-iron.

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  • But the state's iron foundries moved rapidly westward after the first successful experiments in making pig-iron with bituminous coal, in 1845, and the discovery, a few years later, that rich ore could be obtained there at less cost from the Lake Superior region resulted in a decline of iron-mining within the state until, in 1902, the product amounted to only 822,932 long tons, 72.2% of which was magnetite ore from the Cornwall mines in Lebanon county which have been among the largest producers of this kind of ore since the erection of the Cornwall furnace in 1742.

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  • In the manufacture of pig-iron Pennsylvania is easily first among the states, with a product value in 1908 of $111,385,000, nearly 43.8% of that of the entire country.

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  • The value of the output of iron and steel increased from $264,571,624 in 1890 to $471,228,844 in 1905, and the state furnished 46.5% of the pig-iron and 54% of the steel and malleable iron produced in the entire country.

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  • The imports comprise sugar, tobacco, cocoa, coffee, oils, silk and pig iron.

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  • At Rio Tinto the ore is divided into three classes: (I) The poorest, containing an average of about I i% of copper, which is treated locally by leaching with water and liquor containing ferric sulphate, whereby the copper is dissolved out and afterwards precipitated by pig-iron, whilst the residue is exported as ordinary iron-pyrites.

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  • In 1856 Bessemer not only invented his extraordinary process of making the heat developed by the rapid oxidation of the impurities in pig iron raise the temperature above the exalted melting-point of the resultant purified steel, but also made it widely known that this steel was a very valuable substance.

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  • The most important group is that of Cleveland and Durham, which makes about one-third of all the British pig iron.

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  • To make a ton of pig iron needs only about 1.9 tons of ore in the United States, 2 tons in Sweden and Russia, 2.4 tons in Great Britain and Germany, and about 2.7 tons in France and Belgium, while about 3 tons of the native British ores are needed per ton of pig iron.

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  • Grey iron castings are made by remelting the pig iron either in a small shaft of " cupola " furnace, or in a reverberatory or " air " furnace, with very little change of chemical composition, and then casting it directly into suitable moulds, usually of either " baked," i.e.

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  • If the pig iron is to follow path 2, the purification which converts it into wrought iron or steel consists chiefly in oxidizing and thereby removing its carbon, phosphorus and other impurities, while it is molten, either by means of the oxygen of atmospheric air blown through it as in the Bessemer process, or by the oxygen of iron ore stirred into it as in the puddling and Bell-Krupp processes, or by both together as in the open hearth process.

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  • On its way from the blast furnace to the converter or open hearth furnace the pig iron is often passed through a great reservoir called a " mixer," which acts also as an equalizer, to lessen the variation in composition of the cast iron, and as a purifier, removing part of the sulphur and silicon.

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  • In order to utilize this power, the converting mill, in which the pig iron is converted into steel, and the rolling mills must adjoin t h e blast - furnace.

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  • The numerous converting mills which treat pig iron made at a distance will now have the crushing burden of providing in other ways the power which their rivals get from the blast-furnace, in addition to the severe disadvantage under which they already suffer, of wasting the initial heat of the molten cast iron as it runs from the blastfurnace.

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  • Besides a great saving of labour, only partly offset by the cost of repairs, these machines have the great merit of making the management independent of a very troublesome set of labourers, the hand pig-breakers, who were not only absolutely indispensable for every cast and every day, because the pig iron must be removed promptly to make way for the next succeeding cast of iron, but very difficult to replace because of the great physical endurance which their work requires.

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  • Casting the Molten Pig Iron.

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  • - The molten pig iron at many works is still run directly from the furnace into sand or iron moulds arranged in a way which suggests a nursing litter of pigs; hence the name " pig iron."

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  • The chief difficulty in the way of modifying the blastfurnace process itself so as to make it accomplish what the direct processes aim at, by giving its product less carbon and silicon than pig iron as now made contains, is the removal of the sulphur.

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  • Hence, in order to save iron oxide the pig iron used should be nearly free from silicon.

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  • But the strong deoxidizing conditions needed in the blast-furnace to remove sulphur tend strongly to deoxidize silica and thus to make the pig iron rich in silicon.

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  • The " refinery process " of fitting pig iron for the puddling process by removing the silicon without the carbon, is sometimes used because of this difficulty in making a pig iron initially low in both sulphur and silicon.

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  • In this process molten pig iron with much silicon but little sulphur has its silicon oxidized to silica and thus slagged off, by means of a blast of air playing on the iron through a blanket of burning coke which covers it.

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  • In making very low-carbon steel this recarburizing proper is not needed; but in any event a considerable quantity of manganese must be added unless the pig iron initially contains much of that metal, in order to remove from the molten steel the oxygen which it has absorbed from the; blast, lest this make it redshort.

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  • Thus it comes about that the temperature is regulated primarily by adjusting the quantity of silicon in the pig iron treated, of this element usually sufficing.

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  • The slag, in order that it may have such an excess of base that this will retain the phosphoric acid as fast as it is formed by the oxidation of the phosphorus of the pig iron, and prevent it from being re-deoxidized and re-absorbed by the iron, should, according to von Ehrenwerth's rule which is generally followed, contain enough lime to form approximately a tetra-calcic silicate, 4CaO,S10 2 with the silica which results from the oxidation of the silicon of the pig iron and tri-calcic phosphate, 3CaO,P205, with the phosphoric acid which forms. The danger of this " rephosphorization " is greatest at the end of the blow, when the recarburizing additions are made.

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  • The quantity of phosphorus in the pig iron is usually known accurately, and the dephosphorization takes place so regularly that the quantity of air which it needs can be foretold closely.

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  • 80% of phosphorus limits, the use of the process, because there are few ores which can be made to yield so phosphoric a pig iron.

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  • The pig iron should be as nearly free as possible from sulphur, because the removal of any large quantity of this injurious element in the process itself is both difficult and expensive.

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  • Indeed, no limit has yet been found to the temperature which can be reached, if matters are so arranged that not only the carbon and silicon of the pig iron, but also a considerable part of the metallic iron which is the iron itself, are oxidized by the blast; or if, as in the Walrand-Legenisel modification, after the combustion of the initial carbon and silicon of the pig iron has already raised the charge to a very high temperature, a still further rise of temperature is brought about by adding more silicon in the form of ferro-silicon, and oxidizing it by further blowing.

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  • The charge may be melted down on the " open hearth " itself, or, as in the more advanced practice, the pig iron may be brought in the molten state from the blast furnace in which it is made.

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  • Thus part at least of the carbon which a high-carbon steel is to contain may be supplied by the pig iron from which it is made.

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  • The advantage of this combination is that, by simplifying the conditions with which the composition of the pig iron has to comply, it makes the management of the blast furnace easier, and thus lessens the danger of making " misfit " pig iron, i.e.

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  • But if the conversion is only begun in the converter and finished on the open-hearth, then there is no need of regulating the temperature in the converter closely, and variations in the silicon-content of the pig iron thus become almost harmless in this respect.

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  • But if the silicon of the pig iron is removed by a preliminary treatment in the Bessemer converter, then its presence in the pig iron is harmless as regards the open-hearth process.

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  • Hence the blast furnace process, thus freed from the hampering need of controlling accurately the silicon-content, can be much more effectively guided so as to prevent the sulphur from entering the pig iron.

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  • Compared with the Bessemer process, which converts a charge of even as much as 20 tons of pig iron into steel in a few minutes, and the open-hearth process which easily treats charges of 75 tons, the crucible process is, of course, a most expensive one, with its little 80-lb charges, melted with great consumption of fuel because the heat is kept away from the metal by the walls of the crucible, themselves excellent heat insulators.

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  • By rapidly stirring molten iron oxide into molten pig iron in a furnace shaped like a saucer, slightly inclined and turning around its axis, at a temperature but little above the melting-point of the metal itself, the phosphorus and silicon are removed rapidly, without removing much of the carbon, and by this means an extremely pure cast iron is made.

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  • It is by forming calcium sulphide that sulphur is removed in the manufacture of pig iron in the iron blast furnace, in the crucible of which, as in the electric furnaces, the conditions are strongly deoxidizing But in the Bessemer and open-hearth processes this means of removing sulphur cannot be used, because in each of them there is always enough oxygen in the atmosphere to re-oxidize any calcium as fast as it is deoxidized.

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  • basic form, made all of the world's rail steel; but even for this work it has now begun to be displaced by the basic open-hearth process, partly because of the fast-increasing scarcity of ores which yield pig iron low enough in phosphorus for the acid Bessemer process, and partly because the increase in the speed of trains and in the loads on the individual engineand car-wheels has made a demand for rails of a material better than Bessemer steel.

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  • Of the two the cupola is very much the more economical of fuel, thanks to the direct transfer of„ heat from the burning coke to the pig iron with which it is in contact.

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  • - Cupola Furnace for Remelting cast iron of the Pig Iron.

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  • In this last year the United States production of pig iron was nearly 7 times, and that of Germany and Luxemburg nearly 5 times, that of 1880.

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  • We may note with interest that the three great iron producers so closely related by blood-Great Britain, the United States and Germany and Luxemburg-made in 1907 81% of the world's pig iron and 83% of its steel; and that the four great processes by which nearly all steel and wrought iron are made-the puddling, crucible and both the acid and basic varieties of the Bessemer and open-hearth processes, as well as the steam-hammer and grooved rolls for rolling iron and steel-were invented by Britons, though in the case of the openhearth process Great Britain must share with France the credit of the invention.

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  • [[Table Vi]].-Production of Pig Iron (in thousands of long tons).

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  • Production of Pig Iron in the United States (in thousands of long tons).

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  • H.) 1 Calculated from the production of pig iron

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  • Ofthetotal production Engels of pig iron in 1905 amounting to over 10,000,000 tons, more than the half was produced in the Rhineland and Westphalia.

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  • The Barrakur ironworks produce pig-iron, which is reported to be as good as that of Middlesbrough.

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  • The rise of the iron industry dates from the establishment of the Carron ironworks near Falkirk in 1760, but it was the introduction of railways that gave the production of pig-iron its greatest impetus.

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  • In 1901 the number of persons engaged in working of the raw material was 23,263, of whom 8258 were employed in steel smelting and founding, 7781 at blast furnaces in the manufacture of pig-iron, and 7224 at puddling furnaces and rolling mills.

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  • The exports are principally coal, pig iron and ore, steel and stone.

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  • In the first half of the 19th century other exports were lime, freestone, and grain; West Indian, American and Baltic produce, Irish flax and Welsh pig iron were imported, and shipbuilding was a growing industry.

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  • The product of pig-iron in 1908 was 320,458 long tons, valued at $4,578,000.

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  • About 400,000 tons of pig iron are produced yearly, and some of the largest iron-works in the world are situated at Merthyr Tydfil and Dowlais.

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  • - As soon as the pneumatic method of decarburizing pig iron was accepted as practicable, experiments were made with a view to Bessemerizing copper ores and mattes.

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  • These figures include pig-iron produced from foreign ores.

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  • The amount of pig-iron obtained found its minimum, during the period 1890-1910, of 6,976,990 tons in 1893, and its maximum of 10,183,860 in 1906, and in 1905 the quantity produced from foreign ores (4,847,899 tons) for the first time exceeded that produced from British ores (4,760,187).

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  • Sweden possesses little coal, and pig-iron is produced with charcoal only; its quality is excellent, but Sweden's proportion to the world's produce is hardly more than I %, whereas in the 17th and 18th centuries, before the use of coal elsewhere, it was much greater.

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  • Its imports during the same year amounted to 899,201 tons, including 172,319 tons of grain and other agricultural produce, 156,620 tons of firewood, 145,255 tons of pig-iron and manufactured iron and steel, 47,201 tons of iron ore, 121,168 tons of copper, -silver, lead, tin and nickel with their ores and alloys, 63,009 tons of zinc, its ores and alloys, 41,029 tons of sulphur ore, phosphates and other raw material for the chemical trade.

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  • Coal and pig-iron are exported from the mining district inland, and shipbuilding is carried on.

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  • In the coasting trade the exports are mostly pig-iron, codfish and some products of local industries and agriculture.

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  • Several neighbouring cities and towns are also extensively engaged in the same industry, and in 1902 Allegheny county produced about 24% of the pig-iron, nearly 34% of the Bessemer steel, more than 44% of the open-hearth steel, more than 53% of the crucible steel, more then 24% of the steel rails, and more than 59% of the structural shapes that were made in that year in the United States.

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  • The furnaces within the port produce some 2,500,000 tons of pig iron annually.

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  • Experiments he made with South Wales iron were failures because the product was devoid of malleability; Mr GOransson, a Swedish ironmaster, using the purer charcoal pig iron of that country, was the first to make good steel by the process, and even he was successful only after many attempts.

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  • Darby establishes a foundry there using pig iron from the Forest of Dean.

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  • Rotary Furnaces The Holwell site was later expanded to include a foundry to cast the pig iron produced by the furnaces.

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  • Abernant was chosen as the site for a forge and mills where the pig iron produced at Abernant and Llwydcoed could be refined.

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  • Pig iron is manufactured cheaply because of the low price of fuel; in 1907 the value of pig iron manufactured in the state was $6,454,000.

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  • These natural advantages make possible the production of pig iron at an unusually low cost.

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  • In 1900 the Birmingham district produced six-sevenths of the total pig iron exported from the United States, and in 1902 nine-tenths of Alabama's coal, coke and pig iron; in 1905 Jefferson county produced 67.5% of the total iron and steel product of the state, and 62.5% of the pig iron produced by the state.

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  • Production of Material and Pig-Iron and Steel.

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  • Some samples of ore, coal and limestone, obtained in the Mittagong district, with pig-iron and castings manufactured therefrom, were exhibited at the Mining Exhibition in London and obtained a first award.

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  • Very little pig iron is tries US made, most of the iron ore being exported, and iron manufactured consists of old iron resmelted.

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  • For steelmaking foreign pig iron is chiefly used.

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  • The production of pig-iron nearly doubled between 1890 and 1900, increasing from 446,800 tons in the former year to 801,600 in the latter; but since 1900 the output has declined, the total for 1904 (inclusive of Siberia) being 644,000 tons.

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  • Out of an average of some 2,700,000 tons of pig-iron produced annually in the whole of the Russian empire, 61.5% is produced in the basin of the Donets, and out of an average of 2,160,500 tons of worked iron and steel 48.7% are prepared in the same region.

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  • Among the manufactures are charcoal, pig-iron, car wheels and general castings at Lime Rock, cutlery at Lakeville, and knife-handles and rubber brushes at Salisbury.

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  • Its railway car repair and construction shops, belonging to the Norfolk & Western railway, employed in that year 66.9% of the total number of factory wage-earners; pig-iron, structural iron, canned goods, bottles, tobacco, planing-mill products and cotton are among the manufactures.

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  • Timber, pig-iron and iron ore are the leading imports, and coal, produce and iron the chief exports.

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  • More than thirty mineral substances are obtained in commercial quantities from the mines, quarries and wells of New York, but of the total value of the mineral products in 1908 ($45,6 6 9, 861), nearly six-sevenths was' represented by clay products ($8,929,224), pig iron ($15,879,000), stone ($6,157,279), cement ($ 2, 2 54,759), salt ($2,136,738), petroleum ($2,071,533), and sand and gravel ($1,349,163).

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  • In the 18th century it ranked next to Leith as a port, but the growth of Grangemouth, higher up the firth, seriously affected its shipping trade, which is, however, yet considerable, coal and pig-iron forming the principal exports, and pit props from the Baltic the leading import.

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  • Their blast furnaces produce 1,700,000 tons of pig-iron annually.

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  • In the manufacture of vehicles, harness, leather, hardwood lumber, wood-working machinery, machine tools, printing ink, soap, pig-iron, malt liquors, whisky, shoes, clothing, cigars and tobacco, furniture, cooperage goods, iron and steel safes and vaults, and pianos, also in the packing of meat, especially pork,' it ranks very high among the cities of the Union.

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  • As an artificial product, graphite is well known as dark lustrous scales in grey pig-iron, and in the "kish" of iron furnaces: it is also produced artificially on a large scale, together with .carborundum, in the electric furnace (see below).

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  • The yearly production of pig iron a ou had risen to between 500,000 and 600,ooo tons.

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  • Ihe output of pig iron and steel in 1907 was 25,781,361 and 23,362,594 long tons respectively.

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  • Under the stimulus of federal bounties, the production of pig iron and of steel, chiefly from imported ore, is rapidly increasing.

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  • In 1895 it was demonstrated that Alabama pig-iron could be sent to Liverpool and sold cheaper than the English product, and Birmingham (Alabama) came consequently to rank next to Middlesborough and Glasgow among the world centres of the pig-iron trade.

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  • The pig-iron produced in the state in 1860 was valued at $64,590, in 1870 at $210,258, in 1880 at $ 1, 4 0 5,35 6, in 1900 at $13,487,769, and in 1905 at $16,614,577.

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  • In the production of foundry pig-iron Alabama held first rank both in 1900 and in 1905.

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  • Pennsylvania is by far the most important coalproducing state in the Union, and as much of the iron ore of the Lake Superior region is brought to its great bituminous coal-field for rendering into pig-iron, the value of the state's mineral products constitutes a large fraction of the total value for the entire country; in 1907, when the value of the mineral products of the state was $ 6 57,7 8 3,345, or nearly one-third that of all the United States, and in 1908 when the total for the state was $473,083,212, or more than one-fourth that of the whole United States, more than fourfifths of it was represented by coal and pig-iron.

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  • But the state's iron foundries moved rapidly westward after the first successful experiments in making pig-iron with bituminous coal, in 1845, and the discovery, a few years later, that rich ore could be obtained there at less cost from the Lake Superior region resulted in a decline of iron-mining within the state until, in 1902, the product amounted to only 822,932 long tons, 72.2% of which was magnetite ore from the Cornwall mines in Lebanon county which have been among the largest producers of this kind of ore since the erection of the Cornwall furnace in 1742.

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  • In the manufacture of pig-iron Pennsylvania is easily first among the states, with a product value in 1908 of $111,385,000, nearly 43.8% of that of the entire country.

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  • The value of the output of iron and steel increased from $264,571,624 in 1890 to $471,228,844 in 1905, and the state furnished 46.5% of the pig-iron and 54% of the steel and malleable iron produced in the entire country.

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  • The imports comprise sugar, tobacco, cocoa, coffee, oils, silk and pig iron.

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  • At Rio Tinto the ore is divided into three classes: (I) The poorest, containing an average of about I i% of copper, which is treated locally by leaching with water and liquor containing ferric sulphate, whereby the copper is dissolved out and afterwards precipitated by pig-iron, whilst the residue is exported as ordinary iron-pyrites.

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  • In 1856 Bessemer not only invented his extraordinary process of making the heat developed by the rapid oxidation of the impurities in pig iron raise the temperature above the exalted melting-point of the resultant purified steel, but also made it widely known that this steel was a very valuable substance.

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  • The most important group is that of Cleveland and Durham, which makes about one-third of all the British pig iron.

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  • To make a ton of pig iron needs only about 1.9 tons of ore in the United States, 2 tons in Sweden and Russia, 2.4 tons in Great Britain and Germany, and about 2.7 tons in France and Belgium, while about 3 tons of the native British ores are needed per ton of pig iron.

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  • Grey iron castings are made by remelting the pig iron either in a small shaft of " cupola " furnace, or in a reverberatory or " air " furnace, with very little change of chemical composition, and then casting it directly into suitable moulds, usually of either " baked," i.e.

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  • If the pig iron is to follow path 2, the purification which converts it into wrought iron or steel consists chiefly in oxidizing and thereby removing its carbon, phosphorus and other impurities, while it is molten, either by means of the oxygen of atmospheric air blown through it as in the Bessemer process, or by the oxygen of iron ore stirred into it as in the puddling and Bell-Krupp processes, or by both together as in the open hearth process.

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  • On its way from the blast furnace to the converter or open hearth furnace the pig iron is often passed through a great reservoir called a " mixer," which acts also as an equalizer, to lessen the variation in composition of the cast iron, and as a purifier, removing part of the sulphur and silicon.

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  • In order to utilize this power, the converting mill, in which the pig iron is converted into steel, and the rolling mills must adjoin t h e blast - furnace.

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  • The numerous converting mills which treat pig iron made at a distance will now have the crushing burden of providing in other ways the power which their rivals get from the blast-furnace, in addition to the severe disadvantage under which they already suffer, of wasting the initial heat of the molten cast iron as it runs from the blastfurnace.

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  • Besides a great saving of labour, only partly offset by the cost of repairs, these machines have the great merit of making the management independent of a very troublesome set of labourers, the hand pig-breakers, who were not only absolutely indispensable for every cast and every day, because the pig iron must be removed promptly to make way for the next succeeding cast of iron, but very difficult to replace because of the great physical endurance which their work requires.

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  • Casting the Molten Pig Iron.

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  • - The molten pig iron at many works is still run directly from the furnace into sand or iron moulds arranged in a way which suggests a nursing litter of pigs; hence the name " pig iron."

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  • The chief difficulty in the way of modifying the blastfurnace process itself so as to make it accomplish what the direct processes aim at, by giving its product less carbon and silicon than pig iron as now made contains, is the removal of the sulphur.

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  • Hence, in order to save iron oxide the pig iron used should be nearly free from silicon.

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  • But the strong deoxidizing conditions needed in the blast-furnace to remove sulphur tend strongly to deoxidize silica and thus to make the pig iron rich in silicon.

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  • The " refinery process " of fitting pig iron for the puddling process by removing the silicon without the carbon, is sometimes used because of this difficulty in making a pig iron initially low in both sulphur and silicon.

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  • In this process molten pig iron with much silicon but little sulphur has its silicon oxidized to silica and thus slagged off, by means of a blast of air playing on the iron through a blanket of burning coke which covers it.

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  • In the Bessemer or " pneumatic" process, which indeed might be called the " fuel-less " process, molten pig iron is converted into steel by having its carbon, silicon and manganese, and often its phosphorus and sulphur, oxidized and thus removed by air forced through it in so many fine streams and hence so rapidly that the heat generated by the oxidation of these impurities suffices in and by itself, unaided by burning any other fuel, not only to keep the iron molten, but even to raise its temperature from a point initially but little above the melting point of cast iron, say 1150 to 1250° C., to one well above the melting point of the resultant steel, say i soo C. The " Bessemer converter " or " vessel " (fig.

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  • In making very low-carbon steel this recarburizing proper is not needed; but in any event a considerable quantity of manganese must be added unless the pig iron initially contains much of that metal, in order to remove from the molten steel the oxygen which it has absorbed from the; blast, lest this make it redshort.

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  • But two remedies were quickly offered, one by the skilful Swede, Goransson, who used a pig iron initially rich in manganese and stopped his blow before much oxygen had been taken up; and the other by a British steel maker, Robert Mushet, who proposed the use of the manganiferous cast iron called spiegeleisen, and thereby removed the only remaining serious obstacle to the rapid spread of the process.

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  • Thus it comes about that the temperature is regulated primarily by adjusting the quantity of silicon in the pig iron treated, of this element usually sufficing.

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  • The slag, in order that it may have such an excess of base that this will retain the phosphoric acid as fast as it is formed by the oxidation of the phosphorus of the pig iron, and prevent it from being re-deoxidized and re-absorbed by the iron, should, according to von Ehrenwerth's rule which is generally followed, contain enough lime to form approximately a tetra-calcic silicate, 4CaO,S10 2 with the silica which results from the oxidation of the silicon of the pig iron and tri-calcic phosphate, 3CaO,P205, with the phosphoric acid which forms. The danger of this " rephosphorization " is greatest at the end of the blow, when the recarburizing additions are made.

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  • The quantity of phosphorus in the pig iron is usually known accurately, and the dephosphorization takes place so regularly that the quantity of air which it needs can be foretold closely.

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  • 80% of phosphorus limits, the use of the process, because there are few ores which can be made to yield so phosphoric a pig iron.

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  • The pig iron should be as nearly free as possible from sulphur, because the removal of any large quantity of this injurious element in the process itself is both difficult and expensive.

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  • Indeed, no limit has yet been found to the temperature which can be reached, if matters are so arranged that not only the carbon and silicon of the pig iron, but also a considerable part of the metallic iron which is the iron itself, are oxidized by the blast; or if, as in the Walrand-Legenisel modification, after the combustion of the initial carbon and silicon of the pig iron has already raised the charge to a very high temperature, a still further rise of temperature is brought about by adding more silicon in the form of ferro-silicon, and oxidizing it by further blowing.

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  • The charge may be melted down on the " open hearth " itself, or, as in the more advanced practice, the pig iron may be brought in the molten state from the blast furnace in which it is made.

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  • Thus part at least of the carbon which a high-carbon steel is to contain may be supplied by the pig iron from which it is made.

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  • The advantage of this combination is that, by simplifying the conditions with which the composition of the pig iron has to comply, it makes the management of the blast furnace easier, and thus lessens the danger of making " misfit " pig iron, i.e.

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  • But if the conversion is only begun in the converter and finished on the open-hearth, then there is no need of regulating the temperature in the converter closely, and variations in the silicon-content of the pig iron thus become almost harmless in this respect.

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  • But if the silicon of the pig iron is removed by a preliminary treatment in the Bessemer converter, then its presence in the pig iron is harmless as regards the open-hearth process.

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  • Hence the blast furnace process, thus freed from the hampering need of controlling accurately the silicon-content, can be much more effectively guided so as to prevent the sulphur from entering the pig iron.

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  • Compared with the Bessemer process, which converts a charge of even as much as 20 tons of pig iron into steel in a few minutes, and the open-hearth process which easily treats charges of 75 tons, the crucible process is, of course, a most expensive one, with its little 80-lb charges, melted with great consumption of fuel because the heat is kept away from the metal by the walls of the crucible, themselves excellent heat insulators.

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  • By rapidly stirring molten iron oxide into molten pig iron in a furnace shaped like a saucer, slightly inclined and turning around its axis, at a temperature but little above the melting-point of the metal itself, the phosphorus and silicon are removed rapidly, without removing much of the carbon, and by this means an extremely pure cast iron is made.

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  • It is by forming calcium sulphide that sulphur is removed in the manufacture of pig iron in the iron blast furnace, in the crucible of which, as in the electric furnaces, the conditions are strongly deoxidizing But in the Bessemer and open-hearth processes this means of removing sulphur cannot be used, because in each of them there is always enough oxygen in the atmosphere to re-oxidize any calcium as fast as it is deoxidized.

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  • The restriction of the basic Bessemer process to pig iron containing at least i 80% of phosphorus has prevented it from getting a foothold in the United States; the restriction of the acid Bessemer process to pig iron very low in phosphorus, usually to that containing less than o ro% of that element, has almost driven it out of Germany, has of late retarded, indeed almost stopped, the growth of its use in the United States, and has even caused it to be displaced at the great Duquesne works of the Carnegie Steel Company by the omnivorous basic open-hearth.

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  • basic form, made all of the world's rail steel; but even for this work it has now begun to be displaced by the basic open-hearth process, partly because of the fast-increasing scarcity of ores which yield pig iron low enough in phosphorus for the acid Bessemer process, and partly because the increase in the speed of trains and in the loads on the individual engineand car-wheels has made a demand for rails of a material better than Bessemer steel.

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  • Of the two the cupola is very much the more economical of fuel, thanks to the direct transfer of„ heat from the burning coke to the pig iron with which it is in contact.

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  • - Cupola Furnace for Remelting cast iron of the Pig Iron.

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  • In this last year the United States production of pig iron was nearly 7 times, and that of Germany and Luxemburg nearly 5 times, that of 1880.

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  • We may note with interest that the three great iron producers so closely related by blood-Great Britain, the United States and Germany and Luxemburg-made in 1907 81% of the world's pig iron and 83% of its steel; and that the four great processes by which nearly all steel and wrought iron are made-the puddling, crucible and both the acid and basic varieties of the Bessemer and open-hearth processes, as well as the steam-hammer and grooved rolls for rolling iron and steel-were invented by Britons, though in the case of the openhearth process Great Britain must share with France the credit of the invention.

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  • [[Table Vi]].-Production of Pig Iron (in thousands of long tons).

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  • Production of Pig Iron in the United States (in thousands of long tons).

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  • H.) 1 Calculated from the production of pig iron

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  • Ofthetotal production Engels of pig iron in 1905 amounting to over 10,000,000 tons, more than the half was produced in the Rhineland and Westphalia.

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  • The Barrakur ironworks produce pig-iron, which is reported to be as good as that of Middlesbrough.

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  • The rise of the iron industry dates from the establishment of the Carron ironworks near Falkirk in 1760, but it was the introduction of railways that gave the production of pig-iron its greatest impetus.

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  • In 1901 the number of persons engaged in working of the raw material was 23,263, of whom 8258 were employed in steel smelting and founding, 7781 at blast furnaces in the manufacture of pig-iron, and 7224 at puddling furnaces and rolling mills.

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  • The exports are principally coal, pig iron and ore, steel and stone.

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  • In the first half of the 19th century other exports were lime, freestone, and grain; West Indian, American and Baltic produce, Irish flax and Welsh pig iron were imported, and shipbuilding was a growing industry.

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  • The product of pig-iron in 1908 was 320,458 long tons, valued at $4,578,000.

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  • About 400,000 tons of pig iron are produced yearly, and some of the largest iron-works in the world are situated at Merthyr Tydfil and Dowlais.

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  • - As soon as the pneumatic method of decarburizing pig iron was accepted as practicable, experiments were made with a view to Bessemerizing copper ores and mattes.

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  • These figures include pig-iron produced from foreign ores.

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  • The amount of pig-iron obtained found its minimum, during the period 1890-1910, of 6,976,990 tons in 1893, and its maximum of 10,183,860 in 1906, and in 1905 the quantity produced from foreign ores (4,847,899 tons) for the first time exceeded that produced from British ores (4,760,187).

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  • Sweden possesses little coal, and pig-iron is produced with charcoal only; its quality is excellent, but Sweden's proportion to the world's produce is hardly more than I %, whereas in the 17th and 18th centuries, before the use of coal elsewhere, it was much greater.

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  • Its imports during the same year amounted to 899,201 tons, including 172,319 tons of grain and other agricultural produce, 156,620 tons of firewood, 145,255 tons of pig-iron and manufactured iron and steel, 47,201 tons of iron ore, 121,168 tons of copper, -silver, lead, tin and nickel with their ores and alloys, 63,009 tons of zinc, its ores and alloys, 41,029 tons of sulphur ore, phosphates and other raw material for the chemical trade.

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  • Coal and pig-iron are exported from the mining district inland, and shipbuilding is carried on.

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  • In the coasting trade the exports are mostly pig-iron, codfish and some products of local industries and agriculture.

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  • Several neighbouring cities and towns are also extensively engaged in the same industry, and in 1902 Allegheny county produced about 24% of the pig-iron, nearly 34% of the Bessemer steel, more than 44% of the open-hearth steel, more than 53% of the crucible steel, more then 24% of the steel rails, and more than 59% of the structural shapes that were made in that year in the United States.

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  • The furnaces within the port produce some 2,500,000 tons of pig iron annually.

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  • Experiments he made with South Wales iron were failures because the product was devoid of malleability; Mr GOransson, a Swedish ironmaster, using the purer charcoal pig iron of that country, was the first to make good steel by the process, and even he was successful only after many attempts.

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