A method for extracting scandium from scandium-containing materials, said method comprising: re-slurring of a cake of a scandium-containing material with a mixture of sodium carbonate and sodium bicarbonate, carbonization leaching of the scandium-containing material with the mixture of sodium carbonate and sodium bicarbonate in one stage, filtration of the leached scandium-containing material and the precipitation of a scandium concentrate. The carbonization leaching of the scandium-containing material is carried out with a mixture of sodium carbonate and sodium bicarbonate having a Na2CO3 concentration of 130-350 g/dm.sup.3 and a NaHCO3 concentration of 2-100 g/dm.sup.3 at a pH value in the slurry of 9.5-11.0 and a temperature of 20-90 C. For maintaining the required pH value in the slurry, the slurry is gassed with a CO2-containing gas-air mixture. The scandium concentrate is extracted from the filtrate resulting from the leaching process in one stage by treating said filtrate with an alkaline solution.

A method for extracting scandium from scandium-containing materials, said method comprising: re-slurring of a cake of a scandium-containing material with a mixture of sodium carbonate and sodium bicarbonate, carbonization leaching of the scandium-containing material with the mixture of sodium carbonate and sodium bicarbonate in one stage, filtration of the leached scandium-containing material and the precipitation of a scandium concentrate. The carbonization leaching of the scandium-containing material is carried out with a mixture of sodium carbonate and sodium bicarbonate having a Na2CO3 concentration of 130-350 g/dm.sup.3 and a NaHCO3 concentration of 2-100 g/dm.sup.3 at a pH value in the slurry of 9.5-11.0 and a temperature of 20-90 C. For maintaining the required pH value in the slurry, the slurry is gassed with a CO2-containing gas-air mixture. The scandium concentrate is extracted from the filtrate resulting from the leaching process in one stage by treating said filtrate with an alkaline solution.

The invention relates to a method for treating a residue obtained from the chloride process, wherein the residue comprises the components titanium dioxide, coke, an inert metal oxide, and an iron-containing component. Further, the invention refers to the use of this method to separate the components contained in said residue, and to the use of the separated components in the chloride process for obtaining titanium dioxide.

The invention relates to a method for treating a residue obtained from the chloride process, wherein the residue comprises the components titanium dioxide, coke, an inert metal oxide, and an iron-containing component. Further, the invention refers to the use of this method to separate the components contained in said residue, and to the use of the separated components in the chloride process for obtaining titanium dioxide.

Despite the abundance of scandium, its commercial applications continue to be limited by the absence of reliable, secure, stable and long-term production. The subject-matter disclosed herein provides for a method for extracting Rare Earth Elements (REE), scandium and/or Rare-Earth Oxides (REO) from ore and mineral concentrates, the method comprising: providing Rare Earth Elements (REE) and/or scandium bearing feedstock; a high-pressure caustic (HPC) leaching step, comprising leaching the feedstock in an alkali solution at a first temperature for a target period of time and at a given pressure to produce a leachate slurry; extracting a solid residue from the leachate slurry; leaching of the solid residue in a mineral acid to form a primary leach solution; extracting scandium and/or REE from the primary leach solution; and/or precipitating REE remaining in the raffinate to form a mixed REE-carbonate to thereby facilitate the extraction of REO.

Despite the abundance of scandium, its commercial applications continue to be limited by the absence of reliable, secure, stable and long-term production. The subject-matter disclosed herein provides for a method for extracting Rare Earth Elements (REE), scandium and/or Rare-Earth Oxides (REO) from ore and mineral concentrates, the method comprising: providing Rare Earth Elements (REE) and/or scandium bearing feedstock; a high-pressure caustic (HPC) leaching step, comprising leaching the feedstock in an alkali solution at a first temperature for a target period of time and at a given pressure to produce a leachate slurry; extracting a solid residue from the leachate slurry; leaching of the solid residue in a mineral acid to form a primary leach solution; extracting scandium and/or REE from the primary leach solution; and/or precipitating REE remaining in the raffinate to form a mixed REE-carbonate to thereby facilitate the extraction of REO.