MUMBAI, India, Oct. 26 -- Intellectual Property India has published a patent application (202631123732 A) filed by C. V. Raman Global University on October 15, 2026, for A Process For Simultaneous Production Of Potassium Sulphate, Mixed Rare Earth Oxides And Supplementary Cementitious Silicate Material From Nepheline Syenite And Phosphogypsum.
Inventors include Dr Jayashree Samantray; and Dr Amit Anand.
The application for the patent was published on October 23, 2026, under issue no. 43/2026.
Abstract: The present invention relates to an integrated hydrometallurgical process for the simultaneous production of potassium sulphate, mixed rare earth oxides and a supplementary cementitious silicate material from nepheline syenite and phosphogypsum. Pulverised nepheline syenite, of particle size 50 to 70 microns, is mixed with phosphogypsum and roasted in a muffle furnace to convert its potassium content into water-soluble potassium sulphate while simultaneously liberating a calcium- aluminium silicate phase within the roasted mass. The roasted mass is lixiviated with demineralised water, filtered and evaporated to crystallise potassium sulphate as a chloride-free potash fertilizer, with the water vapour recovered during evaporation recycled to the lixiviation step. The resulting insoluble residue is leached with dilute hydrochloric acid, and the dissolved rare earth elements are selectively precipitated using oxalic acid solution and thereafter calcined to obtain mixed rare earth oxides. Iron and aluminium impurities remaining in the leach liquor are removed using calcium hydroxide, and the residual hydrochloric acid is regenerated by carbonation and recycled to the acid leaching step, with calcium carbonate recovered as a further by-product, thereby achieving a lowreagent- consumption, substantially zero-waste valorisation of both feedstocks into fertilizer, rare earth and construction-grade products.
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