Merrill-Crowe Plant Design Factors

The removal of metal values from cyanide solutions, fortunately, can be done in several ways. The oldest practiced method is, cementation with zinc, or Merrill-Crowe. The original patent for recovery of gold and silver from cyanide solutions described precipitation with zinc dust. Most early practitioners, however, used granules of zinc in a successful attempt to … Read more

Hydrodynamic Bearings for Large Diameter Machines

The hydrodynamic bearing has the following characteristics: Lubricant film thickness and pressure are maintained by lubricant which is drawn into a wedge shaped zone between the journal and the bearing, due to their relative velocity and the viscosity of the lubricant. Lubricant flow conditions are laminar. Lubricant film thickness is sufficient to prevent metal to … Read more

Deister Flotaire Column Flotation Cell

The FLOTAIRE Flotation Cell is a column flotation cell designed to utilize aspirated gas in surface tension lowered water to generate extremely fine bubbles. The non-mechanical distribution of the fine bubbles throughout the column without agitation or turbulence allows for greater bubble/particle adhesion. The combined effect of these operating conditions shows enhanced flotation recovery of … Read more

Copper Electrowinning

The very survival of the U.S. copper industry is presently tied to the leach SX-EW process, a technology which 15-20 years ago was considered too radical and far fetched to be accepted by the industry. It came to life rather dramatically with the Ranchers Bluebird Mine and shortly thereafter with the Cyprus Bagdad plant. All … Read more

Classification & Concentration of Heavy Minerals

The recovery of heavy minerals by gravity concentration during grinding is practiced widely in the minerals industry. Studies have shown that the grade and recovery of the concentrate depends not only on the performance of the concentrator but also on the degree of liberation achieved in the mills and the scavenging action of the hydrocyclones … Read more

Charge Motion inside a SAG Mill

For proper design of SAG mills and other types of grinding mills, the operating conditions have to be defined.  Predicting the composition of the SAG mill charge is a difficult task since a number of significant phenomena associated with the charge motion must be taken into consideration. These observations and assumptions led to the recognition … Read more

Autogenous Grinding Iron Ore

Hibbing Taconite is located near the center of the Mesabi Range in Northern Minnesota 100 miles from the Canadian border and 80 miles north of the Lake Superior Port Cities of Duluth and Superior. Current owners of Hibbing Taconite are Bethlehem Steel Corporation, LTV Steel, Pickands Mather and Stelco. Inc. Pickands Mather, a subsidiary of … Read more

Air Classification Working Principles

Regardless of the mechanical design features of a particular air classifier certain basic principles apply. Specifically, there are two forces at work: An air drag force An inertial or centrifugal force. The air drag force has an increasing influence as particles become smaller. A very small low mass particle is easily carried along with an … Read more