Petr Ptáček

Optimal condition includes 2 h of leaching by 6 M HCl at the temperature of 80°C. The pulp

**Fig. 21.** Process flow sheet for the separation of phosphate and recovery of REMs from monazite [62].

410 Apatites and their Synthetic Analogues - Synthesis, Structure, Properties and Applications

The optimization of leaching operation of rare-earth-bearing ores is a complex process since many attributes simultaneously affect the operation, with some of them being conflicting in nature. Therefore, a proper selection of leaching process with pertinent attributes is crucial for the user in order to maximize the percentage recovery at minimal operating costs. The methodology is proposed by BARAL et al [70]. The parameters affecting the performance of

3 Agitation time Choice of leaching agent Mode and cost of transportation of

4 Pressure Acidity of leaching agent Percentage recovery/extraction of

ore to the plant

REEs

Corrosiveness of leaching agent Pretreatment prior to leaching

**Physical Chemical General** 1 Leaching temperature Nature of ore Source of ore 2 Leaching time Grade of ore Cost of ore

density should be of 30 g·dm−3 [62].

leaching operation are listed in **Table 3**.

*n* **Attributes of leaching process**

5 Partial of mesh size of the ore

sample

Brno University of Technology, Czech Republic
