Muffle Furnace
The accuracy of the silver-assay depends in great measure upon a careful regulation of the heat of the muffle furnace during the process of cupellation. At the beginning of the operation, a relatively high temperature is required to ” open ” the lead buttons, that is, to clear off the black film of oxide that […]
Conveyor Belts
About six years ago the writer had occasion to visit a large magnetic iron-ore concentrating-plant, and then saw for the first time rubber belts employed for conveying-purposes. These Conveyor Belts were from 20 inches to 30 inches in width, and some of them were as long as 500 feet between centers. When I spoke of […]
Gravimetric Analysis: Precipitation
After solution, certain minor operations may or may not be necessary, but as a rule the next essential operation is that of precipitation. In his qualitative work the student has already come across many cases of precipitation, and he will find that many of the methods there used are again applied for quantitative purposes. Silver, […]
Gravimetric Analysis: Precipitate Filtration
When precipitation is complete the precipitate must be separated from the solution. The means of bringing about this separation will be described under this head. Under the next head (Washing) the completeness of this separation will be considered. Filtering Medium In quantitative gravimetric analysis the two materials generally used are paper and asbestos, and the […]
Assaying of Silver
There has been considerable discussion of late as to the best method of determining the silver-contents of sulphides of silver resulting from the leaching of silver-ores, and also as to the relative merits of the crucible and the scorification method for the determination of the silver-contents of ores. Owing to the great depression in the […]
Working Principles of Jig: Pulsion & Suction
Jig Acceleration Rittinger, having found that jigs save galena of smaller sizes than his formula, worked out in his appendix of the theory of acceleration to account for that fact, showing that a particle of galena which is equal-settling with a particle of quartz reaches its maximum velocity in perhaps one-tenth the time required by […]
Pre-Sizing Jig Feed Classification
The extent to which sizing by sieves should be carried, as a preliminary to the separation, by jigging, of minerals of different specific gravities, has been a matter of controversy for many years. The subject has been investigated by several authorities, yet the ground does not seem to have been completely covered, nor are the […]
Quantitative Analysis Chemistry: GRAVIMETRIC METHODS
In the course of work completed, the problem so far met with has been the determination of the various elements (or compounds) present in a substance. In an ore, for instance, there may be present silica, iron, copper, arsenic, and sulphur, and it is the province of qualitative analysis to determine the presence or absence […]
CuSO4 Electrowinning with Crystallization
In copper SX processes, the copper extracted from the aqueous feed solution into the solvent is replaced by hydrogen ions given up by the solvent. The aqueous therefore becomes more acidic as it loses copper. To reclaim (strip) the copper from the solvent, this reaction is reversed by contacting the solvent with a more highly […]
Refining of Gold Sulphide with Sulphurous Acid & Hydrogen Sulphide
Since the introduction of the improved method of precipitating gold from chlorine solution by SO2 and H2S at the Golden Reward chlorination-works, Deadwood, S. D., this modern method has been further adopted in the chlorination-works. It has proved practically most successful in the handling of large quantities of gold solution, and constitutes up to date, […]