Variable Speed Pulley

Every constructing engineer and designer knows how often it is desirable to provide a speed-adjustment between parts of a machine performing different functions, or between a prime mover and the devices to which it furnishes power, and how bulky and unsatisfactory are most of the methods by which the result is usually accomplished. Of course … Read more

Phosphorus Determination Method

To have a complete text for a Method for the Determination of Phosphorus we must first discuss the interaction with other elements:  The Effect of Arsenic.—A question involving the temperature of precipitation of ammonium phospho-molybdate, which was brought to my attention some time ago, led to the following experiment: A known quantity of arsenic was … Read more

Magnetic Ore Separator

After considerable experience in connection with the magnetic iron-ores at the South, especially in the Cranberry district of western North Carolina and eastern Tennessee, the writer was led into a thorough investigation of the magnetic separation of iron-ores, and, from this investigation, has gradually been developed a separating machine which it is the purpose of … Read more

Ore Roasting & Oxidizing Furnace

This furnace is designed especially for the oxidation of sulphur or arsenic in pyritic ores, but may be used for all oxidizing or desulphurizing operations, and for calcining, roasting and chloridizing ores, or for drying ores in large quantities preparatory to treatment by magnetic separators or otherwise. It is of the tabular, revolving type, with … Read more

List Minerals Containing Phosphoric Acid

The occurrence and distribution of phosphorus is one of the most important questions with which the steel-maker has to do. Large sums are invested in processes for the removal of this element from ores before they come to the blast-furnace, and much greater sums in freeing the pig-iron from it. Mechanical engineers are becoming more … Read more

Extraction Method of Silver Lead by Smelting

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

Precipitation of Metals from Hyposulphite Solutions

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 is even taken … Read more

How to Remove Fluorine from Copper Concentrates

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

Automatic Ore Sampling Systems

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 by machine. It … Read more

Electro Magnetic Separator

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