Pitch control, minerals

In the pulp and paper industry, mineral raw materials are traditionally called pigments , whether or not they are used to affect color. The use of mineral pigments in the pulp and paper industry fall into five major catagories filling, coating, pitch control, deinking of recycled papers, and microparticle retention. The minerals comonly used for each job are ... 

OSHA regulates the benzene soluble fraction of coal tar pitch volatiles and mineral oil mist, which contain several ofthe PAH compounds. Employers of workers who are occupationally exposed must institute engineering controls and work practices to reduce and maintain employee exposure at or below permissible exposure limits (PEL). The employer must use engineering and work controls, if feasible, to reduce exposure to or below an 8-hour time-weighted average (TWA) of 0.2 mg/m for coal tar pitch volatiles and 5 mg/m for mineral oil mist. 

From a more practical viewpoint, the solvent extraction of bituminous coals has been used as a means of coproducing clean liquid transportation fuels as well as solid fuels for gasification. Coal solvents are created by hydrogenating coal tar distillate fractions to the level of a fraction of a percent, thus enabling bituminous coal to enter the liquid phase under conditions of high temperature (above 400°C [750°F]). The pressure is controlled by the vapor pressure of the solvent and the cracked coal. Once liqnefied, mineral matter can be removed via centrifnga-tion, and the resultant heavy oil prodnct can be processed to make pitches, cokes, as well as lighter products. 

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