Production of titanium compounds and metal by sustainable Methods

Abstract

A unique production of titanium compounds and metal by sustainable methods using iron-titanium oxide starting material such as ilmenite, leucoxene, or rutile is described. Here the iron-titanium oxide compound is prepared by converting the iron portion of the compound to ferrous chloride at low temperatures by using close to stoichiometric amounts of sulfur and chlorine required for all the iron oxides and the other non-titanium oxides. The ferrous chloride thus formed is removed recovering a marketable product of ferrous chloride and the ‘sustainable’ titanium oxide starting material by additional process steps. This can be converted to ‘sustainable’ titanium metal, or titanium tetra-chloride by process shown herein for further conversions to titanium dioxide pigment by present chloride process or supplied to existing titanium sponge producers, benefitting them in having a ‘sustainable process’.

We claim: 
     
         1 . A sequential process for the production of titanium compound and metal by sustainable methods, the said process is carried out utilizing iron oxide containing ores of titanium such as ilmenite, leucoxene, hard rock ilmenite, rutile as well as man-made intermediate compounds such as synthetic rutile along with the use of sulfur and chlorine in a controlled fashion of step-wise addition of the reagent and control of temperatures. 
     
     
         2 . The said process per  claim 1 , starts with the use of stage 1 reactor carrying out controlled chlorination of iron in the mixed oxide to ferrous chloride solids along with unreacted titanium solids, and conversion of the said ferrous chloride to marketable ferrous chloride solution in water of suitable concentration, and making a high grade synthetic rutile with 97-99% TiO 2  which can be either marketed or taken to a next step. The controlled chlorination in stage  1  reactor is carried out by adding stoichiometric amount of sulfur and chlorine needed for conversion of iron to ferrous chloride solids at a temperature of 70 to 250° C., preferably around 130 to 150° C. The products being marketable ferrous chloride solution, high grade synthetic rutile and sulfur dioxide which is sent to a treatment plant making compressed SO 2 , or converted into saleable sulfuric acid. 
     
     
         3 . The said process per  claim 1 , continues with a stage 2 reactor which uses the high grade synthetic rutile of stage 1 [or purchased rutile of equivalent high titanium dioxide content] in a purification stage 2 by removal of rest of the iron as ferric chloride and dimeric ferric chloride vapors along with minimal amount of titanium chloride vapors assuring iron removal. The controlled chlorination carried out by adding with slightly excess of stoichiometric amount of sulfur and chlorine needed for conversion of iron to ferrous chloride solids at a temperature of 500 to 900° C., preferably about 700° C. The product gases are processed to recover the sulfur dioxide to the sulfuric acid plant, and the iron chloride to the marketable ferrous chloride solution, and recovered titanium tetrachloride liquid for further use. The solid product is the ‘sustainable pure titanium dioxide’. 
     
     
         4 . The said process per  claim 1 , using the stage 2 ‘sustainable pure titanium dioxide’ into a marketable milled pigment of different brightness than conventional pigments. 
     
     
         5 . The said process per  claim 1 , continues to stage 3 reactor for producing ‘sustainable titanium tetrachloride’ using the stage 2 ‘sustainable pure titanium dioxide’ with sulfur and chlorine and carrying out the reaction in a controlled fashion, [with added heat if necessary which is supplied by co-burning sulfur with oxygen] along with sulfur dioxide. Parts of the added heat may be supplied by using renewable energy, thus improving the sustainability. 
     
     
         6 . The said process per  claim 1  continues forusing the ‘sustainable pure titanium dioxide’ into ‘sustainable titanium metal’ in a metal producing step alternate 1, by reaction with magnesium metal by controlling the temperature of reaction in the 200 to 900° C. range and preferably around 500 to 600° C. The co-formed magnesium oxide and titanium powder is initially processed by flotation recovering the magnesium oxide values as a marketable product or for reprocessing into magnesium, and minimizing the acid needed to convert the titanium powder into a pure material for further processing into near net-shape final product and or making an ingot of pure titanium for further applications. 
     
     
         7 . The said process per  claim 1 , continues for using the ‘sustainable pure titanium dioxide’ into ‘sustainable titanium metal’ in a metal producing step alternate 2, by reaction with calcium metal by controlling the temperature of reaction in the 200 to 1300° C. range and preferably around 500 to 1050° C. The co-formed calcium oxide and titanium powder is initially processed by flotation recovering the calcium oxide values as a marketable product or for reprocessing into calcium, and minimizing the acid needed to convert the titanium powder into a pure material for further processing into near net-shape final product and or making an ingot of pure titanium for further applications. 
     
     
         8 . The said process per  claim 1 , continues for using the ‘sustainable pure titanium dioxide’ into ‘sustainable titanium metal’ in a metal producing step alternate 3, by reaction with calcium-magnesium alloy by controlling the temperature of reaction in the 200 to 1300° C. range and preferably around 500 to 1050° C. The co-formed calcium-magnesium oxide and titanium powder is initially processed by flotation recovering the calcium magnesium oxide values as a marketable product or for reprocessing into calcium magnesium alloy, and minimizing the acid needed to convert the titanium powder into a pure material for further processing into near net-shape final product and or making an ingot of pure titanium for further applications. 
     
     
         9 . The said process per  claim 1  in which the sustainable titanium metal formed, by any of the three alternate metal produing steps using an alkaline earth metal, such as magnesium or calcium, the alkaline earth oxide recovered from the flotation froth as an alkaline earth hydroxide filter cake is converted back to alkaline-earth metal needed for reduction. This is done in a series of steps—by conversion of the alkaline earth hydroxide to an alkaline earth sulfate hydrate or sulfite followed by being dried into an anhydrous alkaline earth sulfate or sulfite. The anhydrous alkaline earth sulfate or sulfite is treated with sulfur and chlorine producing an anhydrous alkaline earth chloride—such as magnesium or calcium chloride—preferably in a solid state—by controlling the reaction temperature, and minimizing the energy needed. The anhydrous alkaline earth chloride is then used as a feed material to an electrolytic cell where the metal and chlorine are recovered for recycle into the process step. The sulfur dioxide formed in the sulfo-chlorination step is recycled or recovered through the sulfuric acid process. 
     
     
         10 . Conversion of alkaline earth oxide or hydroxide [MgO or CaO] to sulfites using SO 2 , followed by drying to make it anhydrous sulfite, then subjecting the anhydrous sulfite to sulfo-chlorination making anhydrous alkaline earth chloride—suitable for electrolysis to produce alkaline earth metal and chlorine. The sulfur dioxide formed in the preparation of anhydrous alkaline earth chloride is recycled. 
     
     
         11 . Conversion of alkaline earth oxide [MgO or CaO] or hydroxides to sulfates using H 2 SO 4 , and crystallizing to preferably lower hydrates of sulfate [such as kieserite or gypsum]. The lower hydrates of alkaline earth sulfates thus formed or naturally occurring alkaline earth sulfate hydrates are treated by mild calcination to make anhydrous sulfate, then subjecting the anhydrous sulfate to sulfo-chlorination making anhydrous alkaline earth chloride—suitable for electrolysis to produce alkaline earth metal and chlorine. The sulfur dioxide formed in the preparation of anhydrous alkaline earth chloride is recycled.