984 IRON 



notwithstanding a powerful opposition, by a majority of ten members; the measure 

 was however abandoned. 



In France in 1801, the quantity of cast-iron produced amounted to 140,000 tons, 

 from 550 blast-furnaces, of which only one (that of Creusot) was worked with coke. 

 In 1809 a description of the English process of making iron was published by Order 

 of Council, by M. do Bonnard (an engineer of mines) ; another engineer of mines 

 (M. de Gallois), after having passed several months in England, established at St. 

 Etienne the second blast-furnace in France, wherein the minerals wore treated in the 

 same manner as the English, and in which coke was employed ; but the difficulties 

 he had to encounter proved a bar to his success, and he is said to have died prema- 

 turely from the grief and trouble which the enterprise occasioned him (Scrivenor). 

 The employment of pit-coal in the manufacture of iron received a very slow develop- 

 ment in France, for in 1818 the quantity of cast iron made with coke was very small, 

 and no wrought iron was prepared with pit-coal ; in 1824 not more than 3,000 tons of 

 cast iron were made with coke, but in 1828 it had risen to 17,000 tons. Though this 

 did not amount to a tenth of the whole produce, nevertheless the quantity of bars made 

 with pit-coal amounted in this year to 48,000 tons, being nearly one-third of the total 

 manufacture of wrought iron. 



Theory of Iron Smelting The production of metallic iron from its ores is effected 

 by exposing the ore at a suitable temperature to the action of a reducing gas, such as 

 hydrogen, carburetted hydrogen, or carbonic oxide ; the first of these is employed in 

 the laboratory, but for practical purposes only the latter can be used. If the reduc- 

 tion is effected at a comparatively low heat such as a dull redness, the product is a 

 dark grey powder which is stable if kept out of contact with the air, but which burns 

 when shaken out into the air at ordinary temperatures, and still more brilliantly in 

 oxygen, forming the so-called pyrophoric iron. This substance is only of interest as 

 a pharmaceutical product (Ferrum reductum). The reduction by carbonic oxide is 

 effected in all cases where the ore is exposed to the gases arising from the combustion 

 of carbonaceous matter, whether the fuel be burnt separately, as in reverberatory gas 

 or cementation furnaces, or in contact with ore, as in the various forms of blast-fur- 

 nace. The simplest cases which can occur under these circumstances are represented 

 by the following equations : 



I. With hydrogen as the reducing agent Fe 2 s + 3H = 2Fe + 3HO 

 II. carbonic oxide Fe 2 O s + 2CO 



The products vary : in the first case, two equivalents of iron and three of water, and 

 in the second two equivalents of carbonic acid to the same quantity of iron for each 

 equivalent of peroxide of iron. Such a result cannot, however, be got on the large 

 scale, from the fact that finely-divided metallic iron when exposed to a high tempera- 

 ture in contact with carbon either in the solid or gaseous form takes up a proportion 

 of the latter substances, forming carbonised compounds, which are known as malleable 

 iron, steel, and cast iron, according to the amount present. In the first case, the amount 

 is very small, not exceeding a few thousandths of an unit per cent. ; but the presence of 

 carbon may be verified by the production of fetid hydrogen gas, owing to the presence of 

 volatile hydrogen-carbons when even the finest and softest wrought iron is dissolved 

 in an acid. Steel contains from about O'lO to about 2 per cent, of carbon. When 

 the proportion exceeds 2 per cent., and it may in some cases reach as high as 6 per 

 cent., the product is known as cast iron. 



In addition to carbon, iron is found on the large scale to contain other substances; 

 the most important of these in modifying its physical properties are silicon, phosphorus, 

 and sulphur. These are derived from the impurities of the ore ; quartz, phosphate of 

 lime, and some metallic sulphide, being almost invariably present in the minerals 

 treated on the large scale, and a proportion of these substances is certain to bo reduced 

 if the conditions of temperature and exposure be favourable ; silica, under the action of 

 carbon in the presence of iron, being readily reducible in almost any proportion, ac- 

 cording to the temperature ; thus, at a very high heat as much as 22 per cent, of silicon 

 may be combined with iron ; practically, however, nothing like as much can be ob- 

 tained ; about 6 per cent, may be regarded as a maximum. When phosphate of lime 

 is present in the ore under the ordinary condition of reduction in the blast-furnaco, 

 almost the whole of the phosphorus is obtained in the iron. Sulphur is obtained in 

 like manner from metallic sulphides. 



Of the alloys of iron with other metals there is only one of any practical import- 

 ance, namely, that with the allied metal manganese, which may combine with it in 

 all proportions up to about 30 per cent. Copper, when present in iron, even in minute 

 quantity modifies its properties in a marked and prejudicial manner, but there is no 

 proof of these two metals actually combining, 



