The obtaining of polishing materials for the optical industry and the production of special alloys that are based on the ferrous and non-ferrous metals and the catalysts that are used for various purposes require the use of the concentrates of La, Ce or Nd, containing 90-95 percent (rel.) of each of these elements. The analysis of the structure of the production and consumption of the rare-earth elements (REEs) in Japan and China in the course of the last five years (1, 2) has shown that the cerium hydroxides, the REE carbonates of technical purity, and the enriched REE mixtures constitute from 80 percent to 40 percent (rel.) of the overall volume of the REEs that are used. The highest consumption growth rates were noted for the REEs of the cerium subgroup: La, Ce, Nd and Sm.The technology of extraction by separation makes it possible to obtain the entire gamut of REEs of high purity, but its implementation requires large capital investments - and the technological process is characterized by significant operational costs. In this connection the development of a technology for obtaining the REE concentrates (oxides and carbonates) that is based on the use of the differences in the basicity of the REEs and involves lower expenditures for implementation is a very urgent task.
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