Barites

Refractive Index 1.64-1.65 Specific Gravity 4.5 Mohs Hardness 3-3.5 

Other than drilling fluid products, which account for most of production, barite is differentiated according to its chemical and filler uses. 

Drilling grade - Barite for well drilling fluids is typically a 200 mesh product with specific gravity of at least 4.2 (i.e., 90% BaS04 ). Color is not critical, but water-soluble alkaline earth metals are controlled so as not to interfere with drilling fluid rheology. 

Chemical grade - Barite for barium chemicals is -16mm+0.84mm (20 mesh) and contains at least 95% BaS04, 1% SrS04, 1% combined iron oxides, and no more than a trace of fluorine. 

Filler grade - Filler uses for barite generally require high brightness, high purity, and fine particle size, usually -325 mesh or finer. Purity is typically 

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Sulfur occurs native in the vicinity of volcanos and hot springs. It is widely distributed in nature as iron pyrites, galena, sphalerite, cinnabar, stibnite, gypsum, epsom salts, celestite, barite, etc. 

Fig. 1. Global distribution of seabed mineral deposits, where x represents chromite + barite titanium, zirconium, hafnium, and thorium tin I gold, platinum, and silver 3 sand and gravel shell, calcium carbonate gems marine polymetaUic sulfides phosphorites Cl cobalt cmsts S sulfur and B...

Authigenic barium sulfate or barite [13462-86-7] is found in relatively high concentrations in sediments covering active diverging oceanic plate boundaries. It occurs as rounded masses containing up to 75% BaSO or as a dispersed constituent of the sediment. Its origins are uncertain, but it is likely that it is associated with hydrothermal actions. 

Barite, predominately BaSO, meets the overall requirements for weighting material better than other materials and is used for increasing the density of drilling fluids throughout the world. Commercial barite has a lower specific gravity than pure barium sulfate owing to the presence of associated minerals, such as silica. Barite is virtually insoluble in water and does not react with other mud constituents. Most operators prefer barite that meets API specifications (Table 2) (23). The barite content in mud depends on the desired density but can be as high as 2000 kg/km (700 lb/bbl). 

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