Scandium Recovery from Red Mud by Carbonate Assist

Known methods for production of scandium compounds are based mainly on the acidic leaching of scandium-containing materials, followed by its isolation as sparingly soluble compounds. However, these schemes have many operations, consume high amounts of reagents and electric power, resulting in a high cost of the final product. The effect of carbonate ions concentration, contact time, temperature, the ratio of S:L, type and amount of sorbent on the degree of scandium separation directly from red mud slurry was studied in this work. It has been shown that the greatest capacity of macroporous adsorbents exhibit scandium acrylic copolymers iminodifosfonic group situated closer to the polymer skeleton. Keywords: Scandium, red mud, leaching, sorption, ion exchange resin, extractio

Brane world corrections to Newton's law

We discuss possible variations of the effective gravitational constant with length scale, predicted by most of alternative theories of gravity and unified models of physical interactions. After a brief general exposition, we review in more detail the predicted corrections to Newton's law of gravity in diverse brane world models. We consider various configurations in 5 dimensions (flat, de Sitter and AdS branes in Einstein and Einstein-Gauss-Bonnet theories, with and without induced gravity and possible incomplete graviton localization), 5D multi-brane systems and some models in higher dimensions. A common feature of all models considered is the existence of corrections to Newton's law at small radii comparable with the bulk characteristic length: at such radii, gravity on the brane becomes effectively multidimensional. Many models contain superlight perturbation modes, which modify gravity at large scale and may be important for astrophysics and cosmology.Comment: Brief review, 16 pages, 92 references. Some description and references adde