GB836079A - Process for producing titanium tetrachloride - Google Patents

Abstract

<PICT:0836079/III/1> Titanium tetrachloride is produced by feeding a finely-divided mixture of a titaniferous material and a carbonaceous reducing agent downwardly through a reaction chamber concurrent with a stream of chlorine and withdrawing the solid and gaseous reaction products from the bottom of the chamber. The reaction temperature should be above 700 DEG C. and is preferably between 1000 DEG and 1400 DEG C. The solid feed is preferably introduced in suspension in a carrier gas and normally separate from the chlorinating gas stream. The suspended solids, suspended in, for example, nitrogen, carbon monoxide or carbon dioxide with or without additional oxygen to provide supplementary heating, may be introduced in a direction coaxial with the reactor axis and the chlorine may be injected tangentially. The carbon is normally employed in an amount between 15 and 40% by weight of the titaniferous material charged and is in excess of that required to react with the oxygen of the titaniferous material. The chlorine employed is normally the stoichiometric amount but may be less. Reaction times are normally between 1 and 2 seconds. As shown in the drawing, a mixture of titaniferous ore and carbonaceous reducing agent from hopper 1 is fed through a disintegrator 3 to reaction vessel 4 in suspension in a stream of nitrogen introduced at 11. The chlorinating gas is introduced at 13 and passes down with a linear velocity of about 15 cm./sec. The lower end of the reaction vessel is connected to a dust-pot 5 maintained at the lower temperature and from thence the gas is passed through a separator 6 and a condenser 7 for the titanium tetrachloride product. High melting liquid chlorides formed during the reaction adhere to and form a liquid film on the reactor walls, such film flowing down the walls and dripping into the dust pot 5 which is maintained at a temperature such that higher melting chlorides such as alkali or alkaline-earth metal and ferrous chlorides will be present in the solid state; such solidified chlorides are withdrawn through star valve 14 and the gaseous chlorides pass through a line 16 to a chamber 6 maintained at a temperature such that solid ferric chloride will settle out for removal by star valve 17. Suitable titaniferous materials are rutile, ilmenite, titaniferous iron ores and slags and synthetic titanium dioxide. The invention is particularly adapted to deal with such source of materials as contain substantial quantities of alkali or alkaline earth metals. The carbonaceous reducing agent may be carbon, coke or anthracite. The desired reaction temperature may be maintained by adjustment of the charge rate, dilution of the chlorinating gas and by the addition of air or oxygen or pre-heating the raw materials. According to a typical example, a mixture of 7 parts of titaniferous slag and 3 parts of petroleum coke of less than 40 micron size was fed in the stream of nitrogen to a chlorinator pre-heated to 1000 DEG C. Chlorine was introduced separately in stoichiometric amount to react with titanium and the other oxides present; the linear gas velocity was 40 cm./sec. and the retention time 3.5 seconds. The liquid film of contaminating chlorides and adhering dust flowed into the dust pot and on solidification such chlorides were removed, leached to remove soluble chlorides and the leached product was dried and subjected to rechlorination.