**7. Conclusion**

Extraction of thorium as a by-product of REE recovery from monazite and other REE- and Th-bearing minerals (bastnäesite) seems to be the most feasible source of thorium production recently. Processing of monazite to recover REE and thorium has been done in the past in many countries. Main monazite concentrate production is currently taking place in India, Brazil, Malaysia, Thailand, and Vietnam. Substantial but unquantifiable quantities of thorium produced China during the processing of domestic and imported mineral concentrates for production of rare-earth compounds. However, issues associated with thorium's natural radioactivity are a significant deterrent to its commercial use. Consequently, recently the various experimental nuclear reactors based on thorium fuel cycle are operated only in India. In the long term, consumption of thorium could increase substantially if its use as a nuclear fuel becomes commercialized.
