Wad

WAD (EN: wad, black ochre, bog manganese; DE: Wad; FR: wad; ES: wad, groroilita; RU: вад) is the collective name of the minerals, namely, of the earthy mixtures of the manganese hydroxides (with the predominance of the water dioxide, and sometimes of the minerals of the psilomelane group). The chemical composition is variable. The content of the MnO + MnO2 is 32-75%, the content of the H2O is 10-21%. There often exist the diverse admixtures, according to which there is distinguished the series of the varieties, including asbolane (up to 17% of CoO, and 12% of NiO), lampadite (25% of CuO), wackenrodite (30% of PbO), tunnerite (up to 23% of ZnO), tungsten-containing wad (up to 28% of WO3), lithium-containing wad (up to 1% of Li2O), and others. With the decryption of the nature of the minerals, which are composing the wad, the "wad" name is becoming yet less used.

Many wads are the colloidal substances, but more often they are the cryptocrystalline formations. Wad forms the dense and loose earthy, powderish, and sooty masses, incrustations, flowstones, and kidney-shaped isolates. There are typical the dendrites and concretions (in particular, the wad, namely, the so-named pelagite, forms the modern deep-water manganese concretions, which are distributed on the sea bottom). The colour is from dark brown to black. The hardness is usually low (wad often smears hands), but sometimes up to 4. The density is 2800-4400 kilograms per cubic metre. In form of pieces, wad is often very lightweight (very porous).

Wad belongs to the supergene formations; it is typical for the weathering crusts, and for the oxidation zones of the oxide, carbonate, and silicate ores with Mn, but may be found also within the sedimentary formations (the Chiatura deposit within the Georgian SSR, and the Nikopol deposit within the Ukrainian SSR), and within the depositions of the hot water sources (the iron-containing, thorium-containing, and tungsten-containing wads). The lampadites are characteristic for the oxidation zone of the copper deposits (the Dzhezkazgan, Berkara, and other deposits, within the Kazakh SSR, the Kajaran, and Agarak deposits within the Armenian SSR, and others). Wad belongs to the composition of the manganese ores. Certain varieties of wad have the practical significance as the sources for the obtainment of Co, Ni, W, Cu, Pb, and so on.

Wad is being beneficiated according to the combined gravity-flotation schemes, which are including washing, jigging, magnetic separation, and the flotation with the oxyhydryl collectors.