<p>Mixed rare-earth concentrate was mixed with 20 wt.% NaOH and roasted at 650°C for 2&#xa0;h. The bastnasite and monazite in the ore were completely decomposed and transformed into rare-earth oxides (RE_yO_x), rare-earth ferrite (LaFeO₃), and nacaphite (Na₃₀Ca₁₅P₁₅O₆₀F₁₅). The roasted sample was purified by deionized water and dilute hydrochloric acid solution (1.5&#xa0;mol/L) at 50°C for 2&#xa0;h under a water–ore ratio of 2:1 (mL/g) and at a stirring speed of 200&#xa0;rpm. After purification, the main mineral phases were rare-earth minerals. The rare-earth content reached 79.34 wt.% REO, while sodium and phosphorus decreased from 14.76 wt.% Na₂O and 10.78 wt.% P₂O₅ in roasted ore to 1.47 wt.% Na₂O and 1.76 wt.% P₂O₅, respectively. Dephosphorized ore was leached in 7&#xa0;mol/L HCl at 80°C for 2&#xa0;h with an acid–ore ratio of 6:1 (mL/g) and at a stirring speed of 200&#xa0;rpm. The mineralogical phases of leaching residue consisted of mainly rare-earth fluoride, barite, calcium silicate, ferric oxide, quartz and iron phosphate. The rare-earth oxides and rare-earth ferrite disappeared. The leaching rate of rare-earth elements reached about 92.01% and the comprehensive leaching rate of rare earths was about 87.87%.</p>