Electro-Metallurgy

Abstract

ANY metallurgical process which reduces the cost of production as compared with older processes for effecting similar results must of necessity prove of great commercial importance. This is especially the case in places where labour is dear and unskilled, and fuel and refractory materials both scarce and costly—perhaps, even, absolutely unobtainable. If, too, the new process enables a metal to be produced, as in the case of copper, which possesses superior quality to the metal produced by the older process, such a metal will command a higher market price, and the use of the new process is consequently attended with important commercial advantages. Such an improvement over ordinary metallurgical processes has been effected in recent years by the gradual introduction of electrolytic methods. They have not, however, made the rapid progress which was at one time anticipated, and at present are practically only of importance in the metallurgy of copper. There are many reasons for this. The tendency to-day is to endeavour to increase to its maximum the daily output of existing works, provided the product already attainable is of fair quality, rather than to lay down new plant, which, although it might produce a metal of greater purity, would be severely handicapped by the slowness of the work and smallness of the output as a return for the capital invested. It is in this respect that electrolytic methods for the preparation of the ordinary commercial metals fail to give satisfactory results. It is true that in the cases of gold and silver this objection does not to so large an extent apply, but, unfortunately, other circumstances have also to be considered. The metallurgy of the precious metals is for the most part effected in the immediate neighbourhood of the mines, and these, in turn, are usually situated in out-of-the-way districts. Miners, too, and mill-men are generally but slightly acquainted with a knowledge of matters pertaining to electrolytic methods, and comparatively little attention has therefore been directed in the past to the treatment of the ores of the precious metals by such methods. There can, however, be but little doubt that in the near future this will cease to be the case, and that by the improvement of known methods, and by devising new ones, electrolytic methods will attain a degree of commercial importance which at present can hardly be foreshadowed. Any sound contribution to the literature of the subject which is likely to assist in this development of metallurgical processes thus becomes of much importance. We record, therefore, with pleasure, the appearance of a manual by Dr. Gore, devoted to electro-metallurgy proper, which is likely to prove of much use in the spread of the theoretical knowledge so requisite for industrial success. The author gives much attention to this portion of the subject, but in view of the claim “that this book is written to supply a want,” it is to be regretted that fuller details are not forthcoming as to the practical working of the processes, though such information as is given is well and clearly put. The greater part of it, however, has already appeared elsewhere. In the case of copper, for instance, if the working arrangements are faulty, the mud liberated on the solution of the impure copper may be deposited again on the cathodes; the tank solution, too, may vary in density, and the working become irregular with a consequent irregularity in the character of the metal produced. Here, again, excessive rapidity, fatal to the purity of the product, is very common, the result being that in the majority of instances it is necessary to melt the deposited copper, thus introducing sources of error which it is one of the main objects of the process to avoid. The incidental collection of the gold and silver in copper submitted to such a refining process may occasionally cease to be an incident and become the main object of the process, ores of gold and silver being intentionally added in the previous smelting operations.

The Art of Electrolytic Separation of Metals, &c. (Theoretical and Practical).

By G. Gore Electrician Series. (London: The Electrician Publishing Co., 1890.)

A Treatise on Electro-Metallurgy.

By W. G. McMillan Griffin's Scientific Text-books. (London: Charles Griffin and Co., 1890.)