Claims:1. An enhanced reduction process for the production of synthetic rutile having 92% -94% TiO2 content from ilmenite, characterized by:
• reducing ilmenite with petroleum coke and a mixture of borax and ammonium chloride for 3 hours below 10500C in a rotary kiln;
• sieving and removing petcoke from reduced ilmenite;
• leaching said reduced ilmenite by 1% NH4Cl with air purging and continuous stirring for 5 hours;
• leaching the above-leached ilmenite with H2SO4 for 2 hours at below 850C for residual iron removal; and
• calcining and drying the ilmenite.

2. The process as claimed in claim 1, wherein the reduction of ilmenite with petroleum coke and a mixture of borax and ammonium chloride is carried out at a temperature range of 9500C - 10500C.

3. The process as claimed in claim 1, wherein leaching is performed using 0.5 M H2SO4.

4. The process as claimed in claim 1, wherein the reducing agent mixture comprises of pet coke and borax in the ratio 10:1.

5. The process as claimed in claim 3, wherein the leaching is performed at a temperature range of 750C to 850C.
, Description:[0019] The preferred embodiments of the present invention will now be explained in detail. It should be understood however that the disclosed embodiments are merely exemplary of the invention, which may be embodied in various forms. The following description is not to be construed as limiting the invention and numerous specific details are described to provide a thorough understanding of the present invention, as the basis for the claims and as a basis for teaching one skilled in the art how to make and/or use the invention. However in certain instances, well-known or conventional details are not described in order not to unnecessarily obscure the present invention in detail.

[0020] The preferred embodiment of the present invention discloses the production of synthetic rutile from ilmenite using an enhanced reduction process. The ilmenite used is Q grade ilmenite or Quilon grade ilmenite that is mined from the coast of Chavara, Kollam, in Kerala, India. Specifically, ilmenite is reduced with petroleum coke and a mixture of borax and ammonium chloride for 3 hours at 9500C - 10500C in a rotary kiln. The reduced ilmenite is then leached by 1% NH4Cl for 5hours, followed by leaching with 0.5 M H2SO4for 2hours. The final product is washed and dried. The synthetic rutile produced was found to have 92% -94% TiO2 content.

[0021] As per the preferred embodiment of the present invention, ilmenite is reduced using reducing agent mixture of pet coke and borax, plus ammonium chloride mixture at temperature of 9500C - 10500C for 3 hours for metallization of iron. The reduced ilmenite is sieved and pet coke is removed. The reduced ilmenite is then leached with 1 % ammonium chloride solution for 5 hours. The leaching is done for 5hours with oxygen /air purging and with continuous stirring. The pH of the solution for leaching was maintained as obtained. After decanting the leached liquor containing iron, the leached ilmenite is further leached with 0.5 molar dilute solution of sulphuric acid at 750C- 850C for 2 hours for residual iron removal, wherein it is then calcined and stored.

[0022] It was found that increasing the amount of ammonium chloride and borax in the reducing agent, the percentage of titanium dioxide in synthetic rutile had increased gradually from 80% to 86%. The optimum concentration of ammonium chloride and borax is fixed at 0.3%. Increasing the percentage of pet coke to 40%, it was observed that there is good increase in the final titanium dioxide content.

Example 1

[0023] 10 kg of Q grade ilmenite containing 55-60% TiO2 and 25-26.5% total iron was reduced in rotary kiln with 3 kg petroleum coke, 0.3 kg NH4Cl and 0.3 kg borax at 9500C to 1000oC for3 hours. The reduced ilmenite after removal of petroleum coke was leached with 1% solution of ammonium chloride with air purging at a temperature of 800C, for a duration of 5 hours. After said ammonium chloride leaching and removal of iron oxide, the leached ilmenite was further leached with a 0.5 molar solution of concentrated sulphuric acid at 800C for 2 hours. The leached ilmenite was dried and analysed for TiO2 content and it was found to have 92-94% TiO2.

Example 2

[0024] 10 kg of ilmenite containing 49-50% TiO2 content and 30-31% total iron content was reduced in rotary kiln with 5 kg pet coke, 0.5 kg NH4Cl and 0.5 kg borax at 1000oC to 1050oC for 3 hours. The reduced ilmenite after removal of petroleum coke was leached with 1% solution of ammonium chloride with air purging at a temperature of 800C, for a duration of 5 hours. After said ammonium chloride leaching and removal of iron oxide, the leached ilmenite was again leached with a 0.5 molar solution of concentrated sulphuric acid at 780C for 2 hours. Clinkering of the material was found to be present with increasing petroleum coke content. The leached ilmenite was dried and analysed for TiO2 content and the sample was found to have above 90% TiO2.

[0025] Although the present invention has been described in connection with the preferred embodiments thereof, it is to be noted that various changes and modifications are possible and are apparent to those skilled in the art. Such changes and modifications are to be understood as included within the scope of the present invention unless they depart there from.