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A stepwise carbochlorination-chemical vapor transport-oxidation process is developed for the green rare earth extraction from a bastnaesite concentrate using carbon as reductant, chlorine gas as chlorination agent, SiCl 4 gas as defluorination agent, AlCl 3 as vapor complex former, and (O 2 ϩ H 2 O) mixed gas as oxidant. Between 500°C and 800°C, the apparent activation energy of the carbochlorination within 2 hours changed from 17 to 10 kJ/mole roughly for the initial 20 minutes and final 1.5 hours, respectively, in the absence of SiCl 4 , but these values reduced to 15 and 5.9 kJ/mole under 10 kPa of SiCl 4 gas, while the rare earth chloride conversion for 2 hours was 43 to 81 mol pct in the absence of SiCl 4 and 55 to 99 mol pct under 10 kPa of SiCl 4 gas. After carbochlorination at 550°C for 2 hours in the (Cl 2 ϩ SiCl 4 ) atmosphere for efficient rare earth extraction and thorium-free volatile by-product release, thorium was removed by chemical vapor transport at 800°C for 0.5 hours in the (Cl 2 ϩ SiCl 4 ϩ AlCl 3 ) atmosphere and alkaline earths were separated from rare earths by oxidation at 700°C to 1000°C in the (O 2 ϩ H 2 O) atmosphere for 0.5 hours, followed by water leaching at room temperature. Their combination allows a clean and efficient rare earth extraction from the concentrate.

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