GB754889A - Improvements in the production of titanium monoxide - Google Patents

Abstract

Titanium monoxide is formed by reducing titanium dioxide with elemental carbon in two stages. In the first stage an intimate mixture of the dioxide with at least 1/2 but not more than 1 mol of elemental carbon per mol of dioxide is heated to 1100 DEG to 1200 DEG C. whilst removing evolved carbon monoxide and maintaining the temperature until the carbon monoxide evolution ceases thereby producing titanium sesquioxide. In the second stage the sesquioxide is admixed with an equi-molecular quantity of elemental carbon and heated to 1500 DEG to 1800 DEG C. until carbon monoxide evolution has ceased thereby producing the monoxide. If desired the total amount of required carbon can be incorporated in the initial dioxide/carbon mix in which case one mol of carbon per mol of dioxide must be present. Suitable forms of carbon are lamp black or petroleum coke both preferably purified by calcination in a neutral atmosphere to a temperature of at least 1370 DEG C. The reaction is preferably effected in a graphite crucible lined at least on the bottom with molybdenum sheet into which the dioxide/carbon mixture is preferably tamped, blow holes being provided to allow gas evolution. Alternatively the mixture may be briquetted. The furnace should be swept with a current inert gas or preferably, operated under high vacuum that is below 100 microns of mercury. When operating under vacuum the end of both the first and second stages is indicated by the restoration of the vacuum to its original value after a rise due to gas evolution. The titanium dioxide employed is preferably pigment grade but ilmenite or rutile may be employed. Metallic iron formed when ilmenite is employed may be removed by magnetic separation from the final monoxide-containing reaction products.