The bulk of the world’s output of copper is produced by smelting copper sulfide flotation concentrates in reverberatory furnaces, followed by oxidizing the matte to blister copper in a converter. Slags produced in the converter are too high in copper to be sent to the dump and are returned to the reverberatory furnace for recovery … Read more
Potassium is one of the three basic plant nutrients along with nitrogen and phosphorus. There is no substitute for potassium compounds in agriculture; they are essential to maintain and expand food production. Potash is found throughoul the world in both soluble and insoluble forms. Only the soluble forms are economically attractive to process, primarily as … Read more
Primary mercury metal is produced commercially by heating mercury sulfide concentrate in furnaces to vaporize mercury metal, which is cooled and recovered in a condensing system. Potential health and safety problems exist because mercury vapors can escape from the furnace and condenser. The Bureau of Mines and McDermitt Mine, operated by Placer Amex Inc., the … Read more
A large bastnasite deposit was discovered at Mountain Pass, Calif. Subsequent development of the deposit made the United States the world’s largest source of rare-earth minerals. Since then, bastnasite, a fluocarbonate of the cerium-group metals, REFCO3, has replaced monazite as the principal source of rare earths; in 1978 it accounted for more than half of … Read more
There is a wide difference in the floatability of coals of different rank, and even of the same rank, depending on whether they have been freshly mined or allowed to oxidize. Also, differences in floatability, presumably due to oxidation, may occur within a particular seam because of ground water percolating through the coal bed or … Read more
In cleaning coal it has long been recognized that methods which give excellent results for the coarser sizes may give poor or even no cleaning for the finer sizes. Effective cleaning of the fines, therefore, is usually a separate and distinct problem. For many years the problem of fines was considered of relatively minor importance. … Read more
Froth flotation is usually effected by the addition of a collector agent and a frothing agent to an aqueous suspension of suitably comminuted mineral ores. The action of collectors is to adsorb onto the surfaces of minerals to be separated, sensitizing them to bubble adherence. The action of frothers has, in the past, been accepted … Read more
Pyrrhotite has long been considered a gangue mineral to be eliminated as tailing in the treatment of various sulphide ores. However, in recent years the world-wide lack of sulphur resources has called attention to this mineral as a potential source of both sulphur and iron. Its importance as an economic mineral, however, has not been … Read more
On the basis of experiments conducted on quartz using a bubble pick-up method, it was shown in an earlier paper that this mineral will preferentially adsorb hydrogen, calcium, or sodium ions, depending on the relative concentrations of those ions in the solution in which the quartz is immersed. For quartz particles ranging in size from … Read more
The technique of concentrating valuable minerals from lean ores by flotation depends upon the creation of a finite contact angle at the three-phase contact, mineral-water-air. If the mineral is completely wetted by the water phase, contact angle zero, there is no tendency for air bubbles to attach themselves to the mineral. The contact angle is … Read more