METALLURGY. (TITANIUM GOLD, SILVER, PLATINUM, AND MERCURY.) 



385 



intensely powerful current of electricity, the re- 

 sult being a face as hard as glass and of any 

 thickness desired, supported by a tough back, 

 which, it is claimed, can not be cracked. . The 

 depth of the hardening is regulated by the length 

 of time the current plays upon the plate. It is 

 claimed that an average plate can be completely 

 treated electrically in five hours. Moreover, it is 

 asserted that the plate is a third lighter for 

 the same resisting power. 



Among the advantages offered by nickel-steel, 

 R. S. Tappender mentions the smaller liability, 

 arising from its greater tension, of fractures when 

 started to extend, than exists in common steel 

 or iron. The elastic limit of nickel-steel is also 

 much higher in proportion to its tensile strength 

 than that of steel or iron. 



Not many brands of hard tool steel can be used 

 with advantage and economy for the preparation 

 of the various cutting tools employed in the ma- 

 chinery of modern armor-plates. A steel prepared 

 by Sergius Kern, of St. Petersburg, has the fol- 

 lowing composition : 



Tungsten 2.00 per cent. 



Molybdenum 0.50 " 



Carbon 0.90 " 



Manganese 0.20 



Silicon 0.18 



The phosphorus and sulfur must be kept down 

 as low as possible, on the average not more than 

 0.03 per cent, of the combined elements, of which 

 not more than 0.01 per cent, should be sulfur. 

 The steel is, and must be, prepared by the cruci- 

 ble process. Such a self-hardening tool steel is 

 very convenient for the machining of hard metals. 



A paper on the probable existence of a new 

 carbide of iron, Fe 2 C, was communicated by Prof. 

 E. D. Campbell and Mr. M. B. Kennedy, of the 

 University of Michigan, to the Iron and Steel 

 Institute at its summer meeting in Diisseldorf. 



Titanium. In illustration of the importance 

 of the metallurgy of titanium, Mr. Augustin J. 

 Rossi, in the Journal of the Franklin Institute, 

 refers to the extent of the deposits of iron ores 

 containing a notable amount of titanic oxid which 

 occur all over the world in immense quantity, 

 especially in the formations of Sweden, Norway, 

 Canada, North Carolina, and other regions, and 

 the Adirondacks. As a rule, these ores are Bes- 

 semer ores, usually free from phosphorus and 

 sulfur, though not invariably so. It is obvious 

 that if these ores were to regarded in the same 

 light as other ores equally rich in iron, they 

 might form an excellent stock for blast-furnaces 

 for years to come, as their supply might be 

 called inexhaustible. The objections that have 

 been alleged against the use of these ores are 

 characterized by the author as unreliable, con- 

 tradictory, and contrary to the facts. Mr. Ros- 

 si's own experiments and other evidence are 

 cited to show that instead of the presence of 

 titanic acid in blast-furnace slag rendering it 

 infusible, such slags are worked without diffi- 

 culty from that cause. An objection based 

 upon relative economy of production is declared 

 not valid, because of the better quality and 

 higher value of the pig produced from the titan- 

 iferous ores. A general consensus of opinion is 

 alleged to the effect that the pig smelted from 

 really titaniferous ores, whether smelted alone 

 or in important proportions, with other ores, is 

 strong, " wonderfully good," " a splendid iron," 

 " all that can be desired," etc. The addition of 

 from 10 to 15 per cent, of titaniferous pig to a 

 cheap grade of foundry pig raised the tensile 

 and transverse strength, with a deeper chill, 

 and at a cost of several dollars less per ton. 



This titaniferous pig does not, however, contain 

 titanium to any important extent. The influ- 

 ence of that element in the smelting seems to be 

 more one of purification, eliminating obnoxious 

 elements, than a direct one. The author has 

 experimented with alloys of titanium and iron, 

 and has found that as the percentage of titanium 

 increases the fusibility diminishes. All the 

 alloys, both with carbon and those free from 

 it, are much lighter than cast iron, their specific 

 gravities varying with the amount of titanium. 

 Added to steel, titanium increased the ductility 

 considerably. It has been suggested that tita- 

 nium may have an indirect action besides its 

 specific one, when added to steel acting not 

 only as a deoxidizing agent, but also by remov- 

 ing from the steel the nitrogen which is un- 

 doubtedly present in it, and which has an unfa- 

 vorable influence on its strength, titanium burn- 

 ing in nitrogen at 300 C., with incandescence, 

 as iron burns in oxygen. If such be the case, 

 the use of the titanium alloy, even when con- 

 taining carbon, would be well indicated, since 

 the titaniferous ore could be used as a recar- 

 bonizer on account of the high percentage of car- 

 bon it contains, as a deoxidizer (with or without 

 ferro-manganese), and perhaps as a denitrogen- 

 izer; and since, in the case of smaller converters 

 for steel castings, the heat of formation of titanic 

 acid, which is much higher than that of silica, 

 would prove advantageous in raising the temper- 

 ature of the bath, even w r ere but a small percent- 

 age of titanium to remain ultimately in the fin- 

 ished product, there would seem to be, with suitable 

 adaptations of open-hearth furnaces, a promise 

 of the opening for these titanium alloys of a large 

 field of usefulness and for the titaniferous ores a 

 very important application. 



Gold, Silver, Platinum, and Mercury. The 

 oxidized gold ores of the Lydenburg district, 

 Transvaal, are composed of quartz, oxides of 

 iron, and dolomite, and contain, besides the gold, 

 small quantities of manganese, bismuth, silica, 

 and copper. In the cyanid treatment of these 

 ores, manganese dissolves only when an insuffi- 

 cient amount of lime is used, bismuth presents 

 no difficulties, and 10 per cent, or less of silver 

 is recovered. Copper is present in different forms 

 to the extent of 0.4 per cent., and collects in the 

 metallic form on the amalgamating plates, while 

 a small proportion is dissolved by the cyanid, 

 with formation of potassium cuprocyanid, 

 SKCyCuCy. The method of removing the cop- 

 per is to heat the ore with the cyanid solu- 

 tion obtained in ordinary practise, containing 

 cuprocyanid, but no free cyanid. This solu- 

 tion would dissolve the copper, and, after having 

 been freed from it again by the Siemens-Halske 

 electrolytic method of precipitation, could be used 

 over again. 



In pyritic smelting or smelting of dry silver 

 ores in connection with pyrites to form a matte, 

 F. R. Carpenter, dealing with ores of the silicious 

 gold belt near Deadwood, S. Dak., successfully 

 followed the general work of Mansfeld, Germany. 

 The matte fall rarely exceeded 5 per cent. Iron 

 sows formed in the operation, and helped to carry 

 down the gold, so that clear slags could be made 

 in the absence of copper, which has heretofore 

 been deemed essential to the production of waste 

 slags free from precious metal. The refining of 

 the matte Avas at first accomplished by treating 

 with lead ores; then it was found that matte as 

 well as iron sows readily gave up the gold to 

 the lead, while the extraction with silver was 

 not so perfect. In a second method described 

 by the author the matte was smelted for cop- 



