Abstract: Methods and apparatus for the commercial-scale production of purified polycrystalline silicon granules with one or more tailored levels of n- and p-type impurities from an impure silicon source such as, for example, metallurgical-grade silicon.

Abstract: A method and an apparatus are provided for producing discontinuous streams of an inorganic substance, such as a metal, an alloy, a molten salt, slag or matte, or a slurry of ceramic particles, wherein the substance, in the form of a melt or slurry, is maintained in a container at the bottom of which at least one nozzle is provided containing at least one opening having a thickness that is large enough to withstand mechanical and thermal stresses and the melt or slurry is pushed through such opening(s) by means of an impulse applicator positioned over the opening(s) and operating in a periodic manner.

Abstract: A kraft black liquor recovery system utilizing three separate reactors for liquor pyrolysis, sulfate reduction and carbon plus organics combustion, respectively. Oxidized black liquor is pyrolyzed in a fluid bed reactor. The temperature in the fluid bed reactor is 600.degree. C. or lower. The resulting char, containing Na.sub.2 CO.sub.3 and Na.sub.2 SO.sub.4 and a significant amount of carbon, is separated from the pyrolysis gases and introduced in an indirect heated reactor where reduction of Na.sub.2 SO.sub.4 to Na.sub.2 S takes place in the solid state under an atmosphere generated by the reduction. The reduced char is cooled and leached to produce green liquor. The leached char and gases from the pyrolysis and reduction reactors are burned in a fluid bed combustion unit operating below the melting point of mixtures of Na.sub.2 CO.sub.3 and Na.sub.2 SO.sub.4. The fluid bed particles, consisting mainly of Na.sub.2 CO.sub.3 and Na.sub.2 SO.sub.