METALS. 



423 



vertical tubes and down the sloping sides of the 

 hearth ; and, as fast as the contents oi the tubes sub- 

 side or descend, fresh supplies of ore, fuel, and flux, 

 are added, thus rendering the process continuous. 

 The molten metal is run off through a tapping-hole 

 in the side of the furnace, and the slag is removed 

 through a separate opening, from time to time, as re- 

 quired. 



In making wrought iron, the same apparatus is 

 employed, and the wrought iron is obtained direct 

 from the ore. The ore employed should be first 

 reduced to a metallic state, by subjecting it to an 

 elevated temperature in a furnace in contact with the 

 fuel. The ore thus reduced is introduced into the 

 vertical fire-clay tubes, and the process continued as 

 for the production of cast iron, taking care, however, 

 that no coal be mixed with the ore, which would in 

 puch case become carburetted, the result being cast 

 Iron or steel. In making steel, the process is sub- 

 stantially the same as for cast or wrought iron. 



M. Schinz says of this patent that it "is 

 not much more than the ordinary test-process 

 of the laboratory on a larger scale; the only 

 difference being, that, whereas in the ordinary 

 trials a surplus of carbon and scoriae is added, 

 he, M. Ponsard, used merely the exact quantity 

 requisite for carbonizing and smelting. This 

 process, however,- is the same as that going on 

 in the hearth of the blast-furnace when the 

 ores arrive there unreduced. The peroxide of 

 iron (or sometimes the oxide) is reduced by the 

 contact with solid carbon. This reduction, 

 however, is not confined to the oxides of iron 

 alone ; other substances contained in the scorise 

 are affected in the same manner, and yield 

 sulphur, phosphorus, silicium, etc., which are 

 by no means desirable companions for the pro- 

 duced article. In the blast-furnace, hot air, 

 and an insufficient supply of scorise, generally 

 produce this had effect partly; while Ponsard's 

 apparatus is so arranged as to have it through- 

 out. The resulting inferior material will have 

 to be refined, and, in that case, the inventors 

 can hardly claim to have saved any thing by 

 their so-called direct production." 



The Heaton Process. An English transla- 

 tion of a long and able memoir on this process 

 by M. Gruner, Professor of Metallurgy in 

 1'Ecole des Mines, Paris, appears in The En- 

 gineer. Th.e more important details of the 

 process are thus described : 



The purification of pig-iron by the Heaton process 

 is based on the reaction of nitrate of soda, which is at 

 once basic and oxidizing. The nitric acid oxidizes 

 the silicon, the phosphorus, and the sulphur ; the soda 

 seizes on the acids so formed, and withdraws them 

 from the reducing action of the iron. These re- 

 actions are known, but the difficulty in operating on 

 large masses is to obtain a sufficiently intimate con- 

 tact between the molten metal and the nitrate, to pro- 

 duce an -efficient purification, without, however, caus- 

 ing an action so energetic as to result in violent 

 explosions. Mr. Heaton adopted several contriv- 

 ances in succession, which I need not review. It will 

 be sufficient to describe his latest improvement, 

 which has the great merit of being both simple and 

 cheap. 



This apparatus consists of a cylindrical vessel with 

 a movable bottom, a kind of cupola without tuyeres, 

 into which is run the molten metal to be purified. 

 In England it is called a Bessemer' s converter. The 

 movable bottom is a cylindrical caldron of sheet- 



iron, provided with two trunnions, which allow of its 

 being held by a forked lever mounted on a wheel 

 carriage. By this means it is removed and replaced 

 after each operation. The interior of the caldron i* 

 lined with bricks, or refractory clay \vorked into the 

 shape of a hemispherical basin. 



The converter and its movable bottom are pro- 

 vided with flanges, which are held together by clamps 

 and wedges for each operation. The converter itself 

 is lined with fire-bricks, and provided with a sheet- 

 iron chimney like a cupola ; on the top of the chim- 

 ney is a sheet-iron cup, intended to stop the projec- 

 tion of incandescent slag and metal, which might 

 take place in the event of a top violent deflagration 

 of the nitrate. The molten pig is poured into the 

 converter through a lateral aperture, a sort of box 

 funnel, which can be closed at will by a wrought- 

 irpn lid, or simply by a brick. The dimensions vary 

 with the weight of metal to be treated at each opera- 

 tion. There are four converters at Langley Mill, two 

 large and two small ones ; the latter are used for 

 charges of about fifteen cwt., the former for more 

 than double that quantity. But that is not the ne- 

 cessary limit of their capacity, like the Bessemer 

 converters. The essential feature of Mr. Heaton' s 

 invention lies in the arrangement of the nitrate- 

 chamber. To insure the gradual decomposition of 

 the salt by the molten metal, the nitrate must be 

 tightly packed into its chamber, and further protect- 

 ed by a perforated cover. If the stream of molten 

 metal fell directly on the nitrate, it would at once 

 penetrate and force its way to the bottom of the 

 mass. The action would be most violent and instan- 

 taneous, and the alkaline salt would soon float with- 

 out efficiently permeating and reacting on the mole- 

 cules of metal to be purified. To avoid this, the above- 

 mentioned perforated cover is placed over the nitrate 

 when it has been packed into the movable bottom ; 

 it is a thin plate ot cast or sheet-iron, perforated with 

 a great number of holes about i in. in diameter. 

 The principal reagent used by Mr. Heaton is Peruvi- 

 an nitrate of soda ; but he habitually mixes with it a 

 certain proportion of quartzose sand, sometimes 

 lime, peroxide of manganese, flupr spar, etc. "We 

 shall see that quartzose sand and lime are more gen- 

 erally detrimental than otherwise, but peroxide 

 of manganese, carbonate of soda, and sea-salt may 

 advantageously be added to the nitrate. Indeed, Mr. 

 Heaton himself has abandoned the use of lime, and 

 now generally uses from six to twelve per cent, of 

 nitrate with one to one and a half per cent, of 

 sand. 



These two ingredients are thoroughly intermixed, 

 and then closely packed into the nitrate-chamber, 

 which has been previously dried. 



The nitrate used is the ordinary nitrate of com- 

 merce ; it contains from five per cent, to six per 

 cent, of water, and three per cent, to four per cent, 

 of foreign substances. A sample which I brought 

 back from Langley Mill was analyzed at the School of 

 Mines with these results : water, 5.88 ; sand, 0.28 ; 

 sulphate of lime, 0.22 ; chloride of sodium, 2.73 ; 

 pure nitrate of soda, 90.89. It was tested for phos- 

 phoric acid, but it only contained the merest traces 

 of it. According to this, 100 of crude nitrate con- 

 tains 33.27 of soda, or rather 34.7 2 if we reckon in 

 that which is found in the condition of chloride of 

 sodium. 



The molten pig to be converted is tapped out of the 

 blast-furnace or the cupola into a ladle of sufficient 

 capacity to contain the weight of metal to be convert- 

 ed. By means of a crane or a traveller the ladle is 

 brought up to the " box funnel of the converter, and 

 the molten metal is poured into it. If the molten 

 metal be hot and fluid, the reaction begins at once ; 

 the perforated plate lets the metal pass, the nitrate 

 is gradually decomposed, the oxidizing gases, mingled 

 with streams of soda, rise through the bath of pjg, 

 and cause an ebullition more or. less violent, which 

 sometimes makes the whole converter tremble, and 



