A kinetic model for batch leaching of various metals with different lixiviants has been developed. Overall material balances for reactants and products at the solid/liquid interface were formulated with various types of heterogeneous reactions in place at the interface. The solutions to these mass balances have been identified analytically as well as numerically using a … Read more
The separating efficiency of a flotation column is largely limited by the degree of backmixing of tailings into the froth zone, and its recovery is limited by the degree of short-circuiting of feed to the tailings. Current columns are typically made very tall, on the order of 30-40 feet, in order to limit the effects … Read more
Flotation is a well known surface chemistry-based particulate materials separation process which utilizes differences in wettabilities of solids. The operating mechanism in the process is that finely divided particles are rendered hydrophobic by the adsorption of suitable flotation reagents, so that they are captured by the rising stream of bubbles which collide with them. Particles … Read more
Selenium (Se) is encountered in surface and groundwaters in the United States at concentrations that rarely exceed the drinking water standards (0.01 mg/L). However, in the western United States, leachates from heap-leaching operations at gold mines may contain selenium concentrations as high as 2 mg/L. In the gold heap leaching process, a solution containing sodium … Read more
It is obviously well understood that autogenous AG and semi-autogenous SAG mills operate quite differently from conventional rod mill or ball mills. Since these mills are of a grate discharge type, they operate with varying loads, with the power drawn by the mill being dependent upon the volumetric load within the mill and factors that … Read more
Objective: To minimize support costs and to improve ground control by improving wood-crib design and utilisation through the development of engineering methods that will match the placement and performance of the wood cribs to the load conditions imposed by the mine environment. Background: While wood cribs are used extensively to stabilize mine openings, their utilization is often … Read more
Two materials critical to the construction of several advanced photoelectric devices are cadmium and tellurium. CdTe is used in thin-film photovoltaic (PV) devices to absorb electromagnetic radiation (visible sunlight) and convert the energy into an electric current. The Solar Energy Research Institute (SERI) estimates that demand for CdTe in these PV devices could reach 260 … Read more
Potential increases in overall demand and purity requirements of rare-earth elements (REE) prompted the U.S. Bureau of Mines (USBM) to investigate new technology for separating these elements. REE, as defined by the USBM, include a group of 17 elements composed of Sc, Y, and the lanthanides. Although exact numbers are not available because of proprietary … Read more
In researching ways to improve the recovery of minerals from in situ leaching operations. Such operations are amenable to recovering low grade ore, reducing many of the typical mining operations cost, and presenting environmental benefits. Hydraulic properties and characteristics of copper ore are investigated to assess the impact of permeability on flow capacity during in-place, … Read more
A rapidly expanding market for Nd-Fe-B permanent magnets has created intense interest in development of a new process for producing neodymium metal. The current industrial process is calciothermic reduction of neodymium fluoride (NdF3), which entails reacting calcium metal with NdF3 at 1,200° to 1,400° C in closed tantalum crucibles. The process was initially developed for … Read more