Although the subject has no practical bearing on the metallurgy of the present day, it may not be entirely uninteresting to note how the art of silver-lead smelting has been, and in a few remote districts of Peru is still practiced by an old method, and under conditions widely different from our own. The subject … Read more
Table of Contents Metallurgical processes cannot be conducted successfully without the aid of analytical chemistry. The great perfection of lead-smelting in the West, for instance, has only been accomplished by the analysis of ores, fluxes, slags and all products of the furnace. Ores are mixed and fluxed to obtain a slag of desired composition. Account … Read more
Some copper deposits presents a small amount of fluorine associated with copper sulfide ores. Depending on the initial fluorine content and the mineralogical characteristics of the ore, the fluorine may report to the copper concentrate as an impurity. Fluorine levels of more than 200 ppm are subject to penalties in their commercialization. The presence of … Read more
Table of Contents The correct sampling of ores is a subject of far greater importance than is usually conceded to it. Of the little which has been published on this subject, the recent paper, is the latest and best, and well worthy the careful perusal of all interested in accurate sampling, whether by hand or … Read more
The magnetic concentration of iron-ores has been so often and so widely studied and discussed among the members of the Institute that any remarks concerning its general importance, from an economic standpoint, would be superfluous; but it is thought that a description of the Ball and Norton ore-separator, designed for cobbing and separating magnetic iron-ores, … Read more
The occurrence of the tellurides of gold and silver, even in small quantities, is so rare that their metallurgical treatment has engaged little attention. A residence of several months at one of the few mines in North America the product of which consists entirely of such ore, has led me to arrange a method for … Read more
The Transactions of the Institute contain nothing, as yet, on the subject of pocket-compasses; and in the belief that American miners, explorers, geologists, and engineers will gladly welcome any information about new forms of apparatus, simple in construction and adapted to rapid use, I offer a short description of an improved French combination pocket-compass, which, … Read more
Table of Contents The broad general distinction between primary and secondary batteries lies in the fact that in the former the current is produced by the consumption of one or both of the elements composing the cell, while in the latter the elements retain their form as such, and merely pass from one state of … Read more
Invented and first put into use, a “new and useful improvement in rotary ore roasting furnaces,” which was intended “to increase the capacity, effectiveness and working economies of such furnaces.” The following description and accompanying figures are taken from the patent papers: Fig. 1 is a side elevation of the feed-end of the Howell rotary … Read more
Table of Contents Some explanation of methods of testing will be given before presenting the record of a series of physical tests of aluminum, other metals and alloys. The test-bars used, 12 inches long and ½ inch square, are cast in green sand, with chills bedded in such a way that the ends of the bar … Read more