Gravity Concentration

Sand and Gravel Jig

In general, the beneficiation of sand and gravel consists of the removal of certain low specific gravity deleterious particles from the sand and gravel. These particles are coal, lignite, ochre, chert, sandstone, wood, clay, shale, and chalk. These deleterious materials almost always have an apparent specific gravity which is less than 2.35 while good sand … Read more

Launder Washers

Trough washers were among the earliest methods used for concentrating ores; they are referred to by Agricola about the middle of the sixteenth century as already being used while the hand-operated jigging sieve had only recently come into use. For cleaning coal the trough washer apparently was first used in France and Belgium about 1841. … Read more

Principles of Gravity Concentration

Gravity concentration is a general term designating processes for separating and sorting granular material by means of forces that depend on the density, size and shape of the particles. When these forces are applied to the particles the latter are caused to move, those of a given density along one path and those of a … Read more

Humphreys Spiral Concentrator

Since it was introduced in 1943 to recover chromite from Oregon beach sands, the Humphreys spiral concentrator has proved successful in several fields of wet mineral beneficiation. By the end of 1957, 9390 Humphreys spirals had been manufactured. Most of these are still in service. Requirements for Spiral Concentration: Valuable heavy minerals to be recovered … Read more

Dyna Whirlpool Process

The success of Heavy Media Separation, the static sink-float process, is evidenced by the operation of an estimated 300 installations treating many millions of tons per year of a wide variety of mineral products ranging in value from gravel to diamonds. The static heavy media process is usually limited to the treatment of plus ¼ inch … Read more

Separation Efficiency

The technical excellence of separation achieved in a mineral concentration process, or any other process where two constituents of any kind are physically separated from each other, is expressed uniquely and quantitatively by the Separation Efficiency: Es = (R – Rg) where R is the percentage of the valuable constituent and Rg the percentage of … Read more

Batac Jig for Cleaning Fine and Coarse Coal Sizes

The cleaning of coal by the use of jigs is one of the oldest methods of separating coal from its impurities. Although in many situations jigs have been replaced by other methods, by far the largest percentage of coal today is still being cleaned by some form of jigs. Description of the Batac Jig In … Read more

Copper Recovery from Reverberatory Slag

White Pine reverberatory furnace slags contained economically recoverable amounts of copper for a variety of reasons. Among them: White Pine concentrates yield extremely high matte grades (65+% Cu) and viscous slags. The viscous slags hinder matte settling causing matte “prill” entrapment in the slag. White Pine’s total refined copper output is accomplished through fire refining … Read more

Process Plant Design

The radial system simplifies and improves control and supervision to a very considerable extent and can lead to a form of continuous plant operation with the separate sectors shutting down in succession for necessary maintenance while maintaining the overall plant operation. Radial Layout for Increased Treatment-Plant Productivity A great deal of time and trouble is … Read more

Separation of Copper-Nickel by Flotation and Magnetic Methods

As part of our mission to investigate technology options for the development of domestic mineral resources, conducted tests aimed at separating the copper-nickel values in bulk sulfide mattes into copper-rich and nickel-rich fractions. Resources in the Duluth Gabbro Complex are estimated to be 4.4 billion short tons of mineralized rock grading more than 0.50 pct … Read more