The invention relates to a method of separating and extracting rare-earths from rare-earth polishing powder waste and regenerating rare-earth polishing powder, which is characterized by: firstly, process the waste powder with first acid leaching, alkali roasting, and second acid leaching to separate and extract rare-earths from rare-earth polishing powder waste to obtain the leaching solution of rare-earth chloride; secondly, precipitate from the leaching solution with ammonia to remove impurities and hydrochloric acid solution to obtain the purified solution of rare-earth chloride; thirdly, co-precipitate from the solution acquired in the second step with hydrofluoric acid, ammonium bicarbonate, and dispersant to obtain the lanthanum cerium fluoro-carbonate; and finally, after drying, two-stage high-temperature calcination, and ball milling, the regenerated rare-earth polishing powder with decent polishing performance can be obtained. The total leaching efficiency of rare-earths in the rare-earth polishing powder waste of the present invention reaches more than 95%, and the total recovery efficiency of rare-earths reaches more than 93%, which realizes the efficient separation, extraction, and regeneration of rare-earths in the rare-earth polishing powder waste.

A method for dissolving a lithium compound according to the present invention includes bringing a lithium compound into contact with water or an acidic solution, and feeding, separately from the lithium compound, a carbonate ion to the water or the acidic solution to produce carbonic acid, and allowing the carbonic acid to react with the lithium compound to produce lithium hydrogen carbonate.

A method for dissolving a lithium compound according to the present invention includes bringing a lithium compound into contact with water or an acidic solution, and feeding, separately from the lithium compound, a carbonate ion to the water or the acidic solution to produce carbonic acid, and allowing the carbonic acid to react with the lithium compound to produce lithium hydrogen carbonate.

The alunite ore processing method consists of crushing, grinding and flotation of raw alunite ore. The enriched alunite ore is roasted at 520 to 620° C., the roasting time is 1 to 3 hours. The roasted alunite is leached with 5 to 20% sodium carbonate solution, which is in 100 to 110% of the stoichiometric amount required to bond the SO.sub.3 aluminum sulfate in the alunite with leaching conditions of 70-100° C. for 0.5-2.0 hours. The obtained slurry contains all of the potassium sulfate from the alunite and all of the sodium sulfate obtained from sodium carbonate. In the insoluble residue remains all aluminium oxide and residual rock. The sulfate solution is separated from the insoluble residue and is converted with potassium chloride to potassium sulphate (fertilizer) and kitchen salt. The insoluble residue is treated by the Bayer method without the use of an autoclave and results in aluminium oxide (alumina) and quartz sand.

The alunite ore processing method consists of crushing, grinding and flotation of raw alunite ore. The enriched alunite ore is roasted at 520 to 620° C., the roasting time is 1 to 3 hours. The roasted alunite is leached with 5 to 20% sodium carbonate solution, which is in 100 to 110% of the stoichiometric amount required to bond the SO.sub.3 aluminum sulfate in the alunite with leaching conditions of 70-100° C. for 0.5-2.0 hours. The obtained slurry contains all of the potassium sulfate from the alunite and all of the sodium sulfate obtained from sodium carbonate. In the insoluble residue remains all aluminium oxide and residual rock. The sulfate solution is separated from the insoluble residue and is converted with potassium chloride to potassium sulphate (fertilizer) and kitchen salt. The insoluble residue is treated by the Bayer method without the use of an autoclave and results in aluminium oxide (alumina) and quartz sand.

Provided is a method for recovering lithium from a material containing fluorine and lithium. The method includes: mixing the material with an aqueous sulfuric acid solution or water to prepare a mixed liquid; and mixing the mixed liquid with a slightly or sparingly soluble calcium-containing alkaline agent to form a precipitate containing fluorine and calcium, followed by solid-liquid separation to obtain a purified solution having lithium dissolved therein. In the preparation of the a mixed liquid, the material and the sulfuric acid aqueous solution or water are mixed and heated at 60° to 90° C.

Provided is a method for recovering lithium from a material containing fluorine and lithium. The method includes: mixing the material with an aqueous sulfuric acid solution or water to prepare a mixed liquid; and mixing the mixed liquid with a slightly or sparingly soluble calcium-containing alkaline agent to form a precipitate containing fluorine and calcium, followed by solid-liquid separation to obtain a purified solution having lithium dissolved therein. In the preparation of the a mixed liquid, the material and the sulfuric acid aqueous solution or water are mixed and heated at 60° to 90° C.

The invention relates to a method of separating and extracting rare-earths from rare-earth polishing powder waste and regenerating rare-earth polishing powder, which is characterized by: firstly, process the waste powder with first acid leaching, alkali roasting, and second acid leaching to separate and extract rare-earths from rare-earth polishing powder waste to obtain the leaching solution of rare-earth chloride; secondly, precipitate from the leaching solution with ammonia to remove impurities and hydrochloric acid solution to obtain the purified solution of rare-earth chloride; thirdly, co-precipitate from the solution acquired in the second step with hydrofluoric acid, ammonium bicarbonate, and dispersant to obtain the lanthanum cerium fluoro-carbonate; and finally, after drying, two-stage high-temperature calcination, and ball milling, the regenerated rare-earth polishing powder with decent polishing performance can be obtained. The total leaching efficiency of rare-earths in the rare-earth polishing powder waste of the present invention reaches more than 95%, and the total recovery efficiency of rare-earths reaches more than 93%, which realizes the efficient separation, extraction, and regeneration of rare-earths in the rare-earth polishing powder waste.

An active material recovery apparatus capable of easily recovering an electrode active material from an electrode scrap in its intrinsic shape and a positive electrode active material reuse method using the active material recovery apparatus are provided. The active material recovery apparatus which is a rotary firing apparatus comprising a rod in a screw type therein includes a heat treatment bath and a screening wall arranged in a line along an axis of the rod, wherein the heat treatment bath constitutes a heating zone, and the screening wall constitutes a cooling zone; and an exhaust injection and degassing system, wherein the heat treatment bath removes a binder and a conductive material in an active material layer by performing heat treatment on an electrode scrap comprising the active material layer on a current collector in an air while rotating the electrode scrap around the axis of the rod and separates the current collector from the active material layer, and an active material in the active material layer passes through the screening wall and is recovered as an active material in powder form, and the current collector that does not pass through the screening wall is recovered separately.

An active material recovery apparatus capable of easily recovering an electrode active material from an electrode scrap in its intrinsic shape and a positive electrode active material reuse method using the active material recovery apparatus are provided. The active material recovery apparatus which is a rotary firing apparatus comprising a rod in a screw type therein includes a heat treatment bath and a screening wall arranged in a line along an axis of the rod, wherein the heat treatment bath constitutes a heating zone, and the screening wall constitutes a cooling zone; and an exhaust injection and degassing system, wherein the heat treatment bath removes a binder and a conductive material in an active material layer by performing heat treatment on an electrode scrap comprising the active material layer on a current collector in an air while rotating the electrode scrap around the axis of the rod and separates the current collector from the active material layer, and an active material in the active material layer passes through the screening wall and is recovered as an active material in powder form, and the current collector that does not pass through the screening wall is recovered separately.