论文部分内容阅读
The paper describes process details for extraction of rare earths from an intermediate grade concentrate ofMadhya Pradesh region in India and a South African slag. The xenotime concentrate obtained from the former place was anintermediate grade (47%) rare earth phosphate containing both monazite and xenotime. The South African slag was alow-grade waste product typically containing only 4% of rare earths. The rare earth resource concentrates have been treatedindividually by different methods such as alkali fusion and alkali leaching to convert them into their mixed oxides. Bothtypes of materials have been processed and greater than 98% solubilization of metal values has been achieved in the inter-mediate grade xenotime and 80% from the South African slag. The residue of xenotime hydroxide has been washed thor-oughly to collect the sodium phosphate, as by-product and the slurry pH have been adjusted to separate rare earths fromthorium effectively. Other impurities such as uranium and iron have been removed by precipitation of rare earths by oxalicacid. It has been possible to recover >95% yttrium along with other rare earth oxides.
The paper describes the process for extraction of rare earths from an intermediate grade concentrate of Madhya Pradesh region in India and a South African slag. The xenotime concentrate obtained from the former place was an intermediate grade (47%) rare earth phosphate containing both monazite and xenotime. The South African slag was alow-grade waste product containing only 4% of rare earths. The rare earth resource concentrates have been treatedindividually by different methods such as alkali fusion and alkali leaching to convert them into their mixed oxides. Bothtypes of materials have been processed and greater than 98% solubilization of metal values has been achieved in the inter-mediate grade xenotime and 80% from the South African slag. The residue of xenotime hydroxide has been washed thor-oughly to collect the sodium phosphate, as by-product and the slurry pH have been adjusted to separate rare earths from thorium effectively. Other impurities such as uranium and iro n has been removed by precipitation of rare earths by oxalicacid. It has been possible to recover> 95% yttrium along with other rare earth oxides.