Alternate Names: Granular Manganese
In ceramics, it is used primarily in clay and glaze to achieve dark brown or black fired speckle. This is the same material as manganese dioxide powder, it is simply not ground to a fine powder. Typically a 60-80 mesh material is used in amounts around 0.2-0.3%.
Pyrolusite ore is a source of manganese used widely in industry for the manufacture of manganese steel, alkaline batteries, decolorizing glass agents, and in ceramic bodies and glazes. Pyrolusite can contain small amounts of quartz (e.g. 3%) as well as barium compounds (e.g. 2%) and trace amounts of lead (e.g. 0.2%). It is typically about 75% MnO2.
A cone 6 stoneware with 0.3% 60/80 mesh manganese granular (Plainsman M340). Fired from cone 4 (bottom) to cone 8 (top). It is normally stable to cone 8, with the manganese it begins to bloat at cone 7. The particles of manganese generate gases as they decompose and melt, these produce volumes and pressures sufficiently suddenly that closing channels within the maturing body are unable to vent them out.
Out Bound Links
Hazards of these materials in ceramic glazes and clay bodies
Illmenite Granular, Granular Illmenite, Granular Iron Titanate
In Bound Links
Mno2, Pyrolusite, Manganese(IV) oxide
MnO, Manganese(II) Oxide
FERROSO-FERRIC OXIDE, FEROSIC OXIDE