First Indigenous Hafnium plant in India
The first indigenous Hafnium (Hf) Plant in India with an annual production capacity of 320 Kg /annum of Hf metal sponge (with a project outlay of nearly Rs.230 million) has been established and commissioned at C-MET, Hyderabad laboratory. Hafnium metal sponge is being regularly produced and given to end user for further purification and alloy preparation. As on date, the capacity planned fully meets the indigenous applications, however, the pilot plant capacity needs further expansion/ improvement for meeting the extended indigenous demand for cooling rods applications in the modern nuclear energy power plants. Worldwide (including India) hafnium finds applications in rocket nozzles & thrusters, nuclear submarines, nuclear control rods and also striving to be a prominent candidate in future electronic applications. Hafnium project R&D was initiated at C-MET in 2004 and gradually enhanced over the next decade to pilot plant scale. Subsequently, Quality Control (QC) team of VSSC closely monitored the trial runs and certified the quality of the product is suitable to their end use. The extended pilot plant project was sanctioned to C-MET and MoU signed on 31st December 2009 based on the recommendations of a National level Peer Review Committee. Since hafnium and zirconium (Zr) are sister elements available in zircon sand ore, separation of Zr from Hf was a challenge. The other adopted processes for this include calcination, carbo-chlorination, Kroll reduction and separation of magnesium (in vapour phase) & magnesium (Mg) chloride from Hf sponge at high temperature & vacuum conditions. Hf sponge is also pyrophoric in nature. The safety precautions include, the handling of pyrophoric nature of the end product as well as the flammable input gases and raw materials. Safety Audit of the total plant was carried out by External Safety Expert and all suggestions were incorporated, accordingly.
Intel became the first logic device manufacturer to report Hf-based high k metal oxide gate transistors (HKMG) in complementary metal-oxide-semiconductor (CMOS) manufacturing. Since then, Hf-based HKMG technology has gained wide acceptance within the industry. Currently, HfO2 emerges as a leading future candidate to replace Silicon oxide gate dielectric in advanced CMOS applications due to its high dielectric constant value (~25), thermal stability, large heat of formation (271kcal/mol, higher than that of Silica: 218kcal/mol), large band gap (5.8 eV) and high barrier height (1.3eV) that limits electron tunnelling and leakage current. In addition, literature show that HfCo alloy is likely to be a competitor for AlNiCO magnets in the energy product and can replace the most expensive Rare earths (REs) based permanent magnets, predominantly used in large quantities in wind energy and allied applications.
Briefly, hafnium metal is developed indigenously, using indigenous input raw material and it meets national demand fully (if not exports at this stage). Entire process is developed with locally available designs, drawings, skills, etc., which circumvents the expensive imported equipment and their maintenance. In recognition of the indigenization of the above mentioned Chemicals & Materials for space applications, Indian Chemical Council is pleased to confer the ICC Acharya P.C. Ray award for development of indigenous technology for the year 2014 on Vikram Sarabhai Space Centre, ISRO, Thiruvananthapuram, Kerala along with Centre for Materials for Electronics Technology.
This process technology is ready for transfer for interested entrepreneurs, who can run the existing facility and produce sufficient quantities of hafnium using locally available input material using appropriate business model and can supply for the identified and established end users.