Manganese Recycling is essential to iron and steel production in the United States. Demand in metallurgical applications accounts for most of the manganese consumed in the United States, with ironmaking and steelmaking alone consuming 82 pct. The importance of manganese is related to the functions it performs. Manganese controls oxygen and sulfur impurities in steel, … Read more
Chromium is an indispensable element in a variety of strategic and critical applications. It is used to produce steels, superalloys, refractory brick, and a variety of chemicals. There is no substitute for chromite ore in the production of chromium ferroalloys, chromium chemicals, or chromium refractories. There is no substitute for chromium in stainless and heat-resistant … Read more
Summary and Conclusions The treatment of contaminated coal mine drainage requires the precipitation of metal contaminants and the neutralization of acidity. In conventional treatment systems, distinctions between these two treatment objectives are blurred by additions of highly basic chemicals that simultaneously cause the rapid precipitation of metal contaminants and the neutralization of acidity. Passive treatment … Read more
Removal of Contaminants by Passive Treatment Systems Chapter 2 described chemical and biological processes that decrease concentrations of mine water contaminants in aquatic environments. The successful utilization of these processes in a mine water treatment system depends, however, on their kinetics. Chemical treatment systems function by creating chemical environments where metal removal processes are very … Read more
The most common method used for cleaning the fine fraction in today’s coal preparation plants is froth flotation. Past research and practice has found that froth flotation achieves excellent separation efficiencies for fine coals having only a small fraction of middling particles. However, its efficiency decreases sharply as the concentration of middling particles increases due … Read more
The knowledge of aggregate size under various chemical and hydrodynamic conditions is very important for selective agglomeration, flotation and water clarification processes. Traditionally, aggregate size measurements are conducted using an ex-situ technique or in a diluted suspension. In either case, the measurement occurs in an environment that does not resemble the actual conditions under which … Read more
Oleic acid has been almost invariably used in the flotation of siliceous fluorite ores. The performance of oleic acid, however, deteriotates with carbonaceous fluorite ores. Oleoyl sarcosine developed recently has been found to produce results superior over oleic acid with ores containing high calcite contents. While the mechanism of oleate adsorption is usually considered as … Read more
The results of studies to ameliorate acid mine drainage by retarding the rate of oxidation of pyrite at source are discussed. In the transpassive region, pyrite oxidizes by reactive dissolution, mass transfer through the product layer and diffusion in the bulk solution. One can decrease the rate of pyrite oxidation by inhibiting either oxidation reactions … Read more
In this work, the slurry flow in the ball mill is solved with Navier-Stokes’ equations and the marker and cell technique (MAC), which tracks the fluid-free surface. Considering different planes in the radial and axial directions, this numerical approach leads to the direct calculation of the slurry velocity profile, mill holdup, and volumetric flow in … Read more
What is the potential of copper leaching operations in the western states to increase human health risk from drinking water? Should new leach pads be designed for worst case scenarios or for the most likely scenario? With limited funding, is money being spent on highest priority areas to reduce the greatest risk to human health … Read more