Abstract: The invention is concerned with a substantially nitrogen-free process for chloride-route TiO.sub.2 pigment manufacture in which a TiO.sub.2 -containing feedstock is subjected to a fluidized-bed, high temperature carbochlorination in a chlorinator to produce TiCl.sub.4 which is thereafter converted to TiO.sub.2 by oxidation. The TiO.sub.2 -containing feedstock and a solid carbonaceous reducing agent are fed to the chlorinator under a CO.sub.2 blanketing atmosphere such that the carbochlorination is carried out in a substantially nitrogen-free atmosphere containing CO.sub.2 and a CO.sub.2 -rich flue gas is generated, the CO.sub.2 in the chlorinator assisting in controlling thermal balance of the carbochlorination reaction. The absence of significant concentrations of nitrogen in the flue gas results in a favorable condition enabling either or both the CO and CO.sub.2 contained in the flue gas to be readily recovered, purified and sold as by-products.

Abstract: In a steam generating boiler having a bottom wall supporting a char bed and sidewalls with ports through which air is admitted for combustion of combustible species in the char bed and emanating therefrom, combustion is improved by introducing an oxygen-containing gas into a lower central zone of the boiler, from at least one point remote from the sidewalls to thereby cause intimate mixing of the oxygen contained in the gas with the combustible species.