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reducer has to be kept very low, and if this is done, the nickel extracted from a matte originally containing as much as between 6 per cent. and 10 per cent. of iron will not contain more than 0.5 per cent. of iron. If the amount of iron in the residues rises above this percentage, the extraction of the nickel is very much delayed, on account of the low temperature which must be maintained in the reducer. It is necessary, in such a case, to re-smelt the residues before proceeding with the extraction of the nickel and copper. The following are analyses of the deposited nickel :

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The experimental plant at Smethwick has been working for some time, and about 80 tons of nickel have already been extracted in it from different kinds of matte. The results obtained were quite satisfactory, and they point to the conclusion that the process is fully able to compete with any other process at present in use for the production of metallic nickel.

By the kindness of Dr. Mond, the Author is able to exhibit plans for a large manufacturing plant, and Figs. 5, Plate 1, show a vertical elevation, sectional plan and cross-section of it. This plant will, it is estimated, produce 1,000 tons of nickel per year. The plant is so arranged that the matte is continuously charged into the first reducer and traverses the whole set of appliances. When the matte issues from the last volatilizer the first nickel extraction is finished. The matte is re-roasted and submitted to the second copper and nickel extraction. There are ten appliances, consisting of one large reducer, eight combined reducers and volatilizers, and one large volatilizer. They are so arranged that the matte has first to pass through the large reducer, and is then lifted, by means of an elevator and conveyor, into a volatilizer (erected on the top of the next reducer). The relative positions of the reducers and volatilizers are best shown in the cross section, Figs. 5. It passes through the volatilizer into the upper portion of the reducer and in traversing this it is further reduced. It is then lifted again to the next volatilizer, and so on till it finally reaches the larger volatilizer

at the end of the whole series, and, after passing through this, it is discharged into the roasting furnace. The conveyor on the top of the volatilizers into which the elevators discharge, is common to the whole set of volatilizers and reducers, so that, in case any portion of the plant has to be disconnected, the rotary valve through which the material is discharged from the conveyor into the volatilizer is stopped. The material then passes on through the conveyor into the next volatilizer. The two gases, carbon-monoxide in the volatilizers and water-gas in the reducers, are kept separate by rotary valves of the same construction as in the small plant. The water-gas connections are so arranged that each reducer receives fresh gas from the main, with the exception of the first large reducer, through which the waste gas of all the other reducers is passed, so as to burn completely all the hydrogen in the water-gas. The carbon-monoxide passes through the volatilizers from a common main, and is collected, after it has passed through the filters, in a main leading to the blower. From the blower the carbon-monoxide charged with nickel passes through a set of decomposers, and again into the main which feeds the volatilizers.

With regard to the application of steel containing between 1 per cent. and 7 per cent. of nickel in constructive work, the Author need not remind members of the Institution of the importance of nickel steel not only for the manufacture of armour-plates but for all purposes where strength and lightness are essential. One manufacturer in the United States used in 1 year no less than 178 tons of nickel in the form of nickel steel, and it has been stated by a competent authority that "if propeller shafts were made of nickel steel the question of failures would seldom or never be raised." An attempt to deal adequately with the application of nickel would lead far beyond the scope of the present Paper, and the Author only adds that the extraordinary properties of these alloys have formed the subject of elaborate investigations by the late Dr. John Hopkinson1 and by Mr. Guillaume.2

The Author acknowledges his indebtedness to Dr. Mond and to Dr. Langer for enabling him to examine the Smethwick Works in detail and for the drawing they prepared for him of the plant. The Author's assistant, Dr. Stansfield, was by Dr. Mond's kindness

1 Proceedings of the Royal Society, vol. xlvii. p. 23; vol. xlvii. p. 138; vol. xlviii. p. 1.

* Comptes rendus, vol. cxxiv. pp. 176, 752 and 1515, and vol. cxxv. p. 235.

able to watch every stage of the process during a prolonged visit to the Works.

It will have been evident that the process possesses unusual interest as being the only one, in the whole range of metallurgy, in which a metal is obtained from its ores by causing it to combine with a gas to form a gaseous product from which it is subsequently released. Not the least remarkable feature of the process is presented by the fact that the temperature at which the whole operation is conducted never exceeds 300° C., which is far below dull redness. As a consequence, the plant, which may still admit of simplification, is not, as is usually the case with metallurgical appliances, subjected to alterations of temperature extending through a considerable range. The repairs needed are therefore inconsiderable, and the amount of fuel required is but small. The process works more or less automatically, and the amount of labour involved in conducting it can be reduced within very narrow limits. The main operation is, moreover, a regenerative one; the carbon-monoxide moves in a cycle and is the vehicle for continuously transferring the nickel from the ore or matte, and converting it into a marketable form. It follows that in the extraction of the nickel no new material except the reducing agent, water-gas, has to be introduced into the system. This is true even of the granules of commercial nickel which fill the decomposer and serve as a basis for the deposition of the nickel from the carbonyl. Their presence is essential in starting the process; but their place is, as has already been pointed out, gradually taken by fragments of the deposited metal which becomes detached as the operation proceeds. The process will always occupy a prominent place in chemical history, and there would seem to be no reason why it should not play an important part in metallurgical practice.

As regards the application of the process in Canada, the Author trusts that this attempt to make it better known may contribute to develop one of the resources of the great Dominion.

The Paper is accompanied by six drawings and a photomicrograph, from which Plate 1 and the Figures in the text have been prepared.

Discussion.

Mr. W. H. PREECE, C.B., F.R.S., President, said it was his first Mr. Preece. duty to propose, and he was sure it would be carried with acclamation, a vote of thanks to the Author for the extremely clear and able way in which he had brought before the members a process that appeared to be new from beginning to end. It was one which they would watch with great interest and hope to have further light thrown upon. To many it was startling to think that nickel could be converted into a gaseous form, and from the gas the solid metal that was so much required extracted by moderate increase of temperature.

Austen.

Prof. ROBERTS-AUSTEN, C.B., remarked that as the process was Prof. Robertsof such great interest to Canada, he might be permitted to read a telegram he had received from Lord Strathcona and Mount Royal, the High Commissioner for the Dominion :-"I am exceedingly sorry that owing to a severe cold I am compelled to deny myself the pleasure of being with you this evening. Your address would have had great interest for me, seeing how important the nickel industry is to Canada. Please accept my sincere regrets." He would first call attention to the liquid carbonyl compounded of carbonic oxide and iron. A sample was exhibited, for which the Institution was indebted to the kindness of Dr. Mond, together with a sample of the fluid carbonyl of nickel; but it was so poisonous that he feared to leave it where the tube in which it was contained might become fractured. He desired to show the actual experiment upon which the whole beautiful process was based, but it was an exceedingly delicate one to bring from a laboratory and show in a room far away from the place in which it had been arranged. The gasholder contained carbonic oxide, and a little of the gas was ignited to show that it burnt with the characteristic flame of that gas. This gasholder, Fig. 6, corresponded with the carbonic oxide retort of Figs. 1 and 2, Plate 1. The gas was then passed over finely divided metallic nickel at a temperature not necessarily exceeding 50° C., and the luminosity of the flame was materially increased. The tube containing the nickel corresponded with the portions of the plant called "volatilizer" in Plate 1. In a very few minutes the carbonic monoxide took up its charge of nickel, and there was a luminous flame which deposited its nickel on any cold surface held over it. The

Austen.

Prof. Roberts- flame was fully charged with nickel and deposited a black layer of the metal on a plate of cold porcelain. It could be seen within what a very small range of temperature the whole operation was conducted. By passing the gas into a tube, and by heating it, a brilliant deposit of metallic nickel was obtained on the inside, in the form of a mirror. This tube corresponded with the "volatilizers " of the plant shown in Plate 1. The plate of solid nickel, which he exhibited, stripped off a sheet of iron on which it had been deposited, was prepared precisely as shown by the experiment, only in a large retort. He also exhibited granules of nickel having a core of ordinary commercial nickel. If the nickel carbonyl was introduced into an ordinary non-luminous Bunsen burner it instantly became luminous. Photographs were projected upon the screen to illustrate (1) the roasting bed of the great ore deposit

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in the district near Sudbury; (2) a mass of nickeliferous regulus resulting from the process of heap roasting, showing on what a grand scale the operation was now conducted; (3) a magnified granule of ordinary commercial nickel surrounded by concentric layers of nickel, Fig. 4. The central core was unduly large. In conducting the process on the large scale, no new granules had to be introduced into the system, because the fragments of the external layers became detached and so served as a basis for the deposition of fresh quantities of nickel from the carbonyl; (4) an enlarged view of a granule showing the crystalline structure of the ordinary commercial nickel, which contained carbon, while the banded layers were magnifications of the pure nickel deposited on the nucleus of commercial nickel; and (5) heating and cooling curves of metallic nickel registered by means of an autographic pyrometer. As the nickel attained a temperature of 600° C. there was a distinct

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