Patent US10640847

treating the fluorine-containing ore or concentrate by carbochlorination in the presence of a carbon-containing material and a fluorine capturing agent to form a mineral chloride and a treated ore or concentrate, wherein the fluorine capturing agent prevents formation of rare earth fluorides by forming a fluoride more thermodynamically stable than rare earth fluorides during carbochlorination;

contacting the treated ore or concentrate with a HCl leach solution to solubilize the mineral chloride in the leach solution; and

recovering the mineral,

wherein the mineral is selected from the group consisting of a rare earth mineral, a scandium mineral, a niobium mineral, a tantalum mineral, a zirconium mineral, a hafnium mineral, a titanium mineral, and combinations thereof, and

wherein fluorides remaining in the treated ore or concentrate after the treating step are insoluble in the HCl leach solution.

(a) agglomerating the fluorine-containing ore or concentrate with a carbon-containing material, a fluorine capturing agent, and a binder to produce an agglomerate;

(b) carbochlorinating the agglomerate by exposing the agglomerate to chlorine gas to produce a calcine;

(c) leaching the calcine by contacting the calcine with a hydrochloric acid solution having a pH of less than about 4.0 to produce a mixture of a liquid and a solid; and

(d) recovering the mineral by contacting the liquid of the mixture with at least one of sodium hydroxide, ammonium hydroxide and magnesium hydroxide,

wherein the fluorine capturing agent prevents formation of rare earth fluorides throughout step (b).