Braunite

BRAUNITE (according to the name of the German scientist M. Braun (sic) or accoring to the name of Wilhelm von Braun (1790–1872) * EN: braunite; DE: Braunit; FR: braunite; ES: braunita; RU: браунит) is the mineral within the group of the complex oxides, Mn2+ Mn63+ SiO12. There exist the admixture of iron (up to 18% within the ferribraunite). It crystallizes itself into the tetragonal crystal system. The crystal structure is coordinated, similar to the structure of fluorite. The crystals are bipyramidal, with the pseudo-octahedral appearance. Most often, it forms the continuous granular aggregates. The colour is black, sometimes with the brownish tinge, or steel-gray. It is opaque. It is brittle. The cleavage is perfect (along the bipyramid). The hardness is 6-6.5. The density is 4800±100 kilograms per cubic metre. According to the origin, it is metamorphic, less often hydrothermal; sometimes it may be found within skarns. It is widely distributed within the oxide ores of manganese, within many slightly metamorphosed sedimentary and volcanogenic-sedimentary deposits (for example, the Dzhezda, Karazhal, and other deposits within the Central Kazakhstan). Within the zone of oxidation, it gradually transitions into psilomelane, and later into pyrolusite.

Braunite is the important manganese ore, which is used for the obtainment of ferromanganese and "specular pig iron" (spiegeleisen), it is also used as the flux during the smelting of steel. It is beneficiated according to the combined schemes, which are including washing, jigging, magnetic separation, and flotation within the alkaline environment, to which are subjected the sludges (with the size of particles of less than 0.1 millimetres), concentrates, which are requiring fine-tuning, and industrial products of the gravitational stage. It is flotated by the oxyhydryl collectors with the addition of the hydrocarbon oils and emulsifiers. The regulator of the environment is soda.