| 摘要 |
<p>Gases produced by the chlorination of oxidic ores in the presence of a reducing agent at high temperature, and containing volatile chlorides, hydrogen chloride and oxides of carbon are cooled to a temperature somewhat above the dew point of the normally liquid chlorides, the condensed solid chlorides are removed, and the liquid chlorides are therefrom condensed in cooling stages of decreasing temperatures, the temperatures being so adjusted that normally solid chlorides condensing with the liquid chlorides are held in solution. They are precipitated in a separate operation by cooling the solutions. Normally liquid chlorides are those of titanium, tin, and silicon. Normally solid chlorides are those of iron, aluminium, zirconium, chromium, tantalum, niobium and thorium. Gases obtained by the chlorination of titanium ores at say 800 DEG C may thus be cooled to 120-150 DEG C to precipitate iron and zirconium chlorides, and titanium tetra-chloride then condensed successively at down to 40 DEG C, at down to 10 DEG C, and at -20 DEG C to -30 DEG C. Volatile chlorides still present in the gases may be removed by solid adsorbent, e.g. active carbon, alumina, silica gel, and recovered by heating the adsorbent at 300-600 DEG C at normal or reduced pressure, or in an inert gas, e.g. the chlorination gas freed from chlorides. Hydrogen chloride is recovered from the residual gas by washing with water, or hydrochloric acid and water in a multistage process. The residual carbon monoxide-containing gas may be used as a fuel, or, after drying, as an auxiliary gas in the process of Specification 661,685. Two forms of apparatus are indicated, the one in which the liquid chlorides are condensed in tubular coolers with indirect cooling, the other in which cooling is effected by sprays of cooled chloride, especially the cooled condensate passed countercurrently to the flow of the gases.</p> |
