A process for producing alumina and a lithium salt comprising the steps of: (a) calcining an alpha spodumene ore or concentrate to produce beta spodumene; and (b) (I) leaching beta spodumene from the calcining step (a) with an alkaline solution under pressure; or (II) sulphating beta spodumene with at least sodium sulphate and leaching said sulphated beta spodumene to produce a lithium containing solution and a zeolitic residue. The lithium containing solution is treated to provide a purified lithium salt and said zeolitic residue is treated to provide high purity alumina.

A method for the recovery of vanadium from a vanadium containing feed stream, the method comprising the steps of: subjecting the vanadium feed stream to a leach step, the leach step comprising contacting the vanadium feed stream with an alkaline carbonate leach solution to form a leach slurry comprising a pregnant leach solution containing vanadium and a solid residue; passing the leach slurry to a solid/liquid separation step to produce a pregnant leach solution containing vanadium; and recovering a vanadium product from the pregnant leach solution.

A method for the recovery of vanadium from a vanadium containing feed stream, the method comprising the steps of: subjecting the vanadium feed stream to a leach step, the leach step comprising contacting the vanadium feed stream with an alkaline carbonate leach solution to form a leach slurry comprising a pregnant leach solution containing vanadium and a solid residue; passing the leach slurry to a solid/liquid separation step to produce a pregnant leach solution containing vanadium; and recovering a vanadium product from the pregnant leach 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.

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.

Methods for obtaining solid products and combustible gas using aluminum waste are disclosed. In some embodiments, a method for obtaining solid products and combustible gas using aluminum waste may comprise: obtaining a reactive mass, the reactive mass comprising aluminum remelting waste or a derivative thereof; applying a solvent to the reactive mass to generate a solution and a first solid product; separating the solution from the first solid product; applying a reactant to at least a portion of the first solid product to initiate a reaction, the reactant being different from the solvent, the reaction generating a combustible gas and a second solid product; and separating the reactant from the second solid product.

The present invention provides an environmentally safe method of collecting rare earth elements from mineral sources such as bastnasite deposits. The invention uses calcium hydroxide to decompose rare earth element minerals and avoids the use of sulfuric acid decomposition which produces toxic hydrofluoric acid as a byproduct. The invention's use of calcium hydroxide produces calcium fluoride as a byproduct which is non-toxic and has a number of industrial uses. The invention further provides a method of separating mixed rare earth element leachates into heavy and light rare earth element fractions using inorganic sodium salts as a precipitation agent.

The present invention discloses a method for effectively decomposing mixed wolframite and scheelite ore in an alkaline system, specifically comprising steps of: grinding mixed wolframite and scheelite ore, putting in an autoclave, adding an appropriate amount of water, and then adding sodium phosphate, sodium hydroxide and calcium fluoride for decomposition, and treating by solid-liquid separation to obtain crude sodium tungstate solution. The present invention has the advantage that the high-efficiency decomposition of the mixed wolframite and scheelite ore can be realized with low consumption of leaching agents. By this method, the mixed wolframite and scheelite ore can be directly treated by an existing tungsten smelting autoclave, with low leaching cost, high decomposition rate and easy industrial application.

The present invention discloses a method for effectively decomposing mixed wolframite and scheelite ore in an alkaline system, specifically comprising steps of: grinding mixed wolframite and scheelite ore, putting in an autoclave, adding an appropriate amount of water, and then adding sodium phosphate, sodium hydroxide and calcium fluoride for decomposition, and treating by solid-liquid separation to obtain crude sodium tungstate solution. The present invention has the advantage that the high-efficiency decomposition of the mixed wolframite and scheelite ore can be realized with low consumption of leaching agents. By this method, the mixed wolframite and scheelite ore can be directly treated by an existing tungsten smelting autoclave, with low leaching cost, high decomposition rate and easy industrial application.

A production method includes: an alkali extraction step of adding an alkali and water, or an alkali solution, to raw material ash containing an ammonium sulfate component, sulfuric acid, vanadium, and at least one other metal selected from nickel, iron, and magnesium, wherein a pH of 13 or higher is achieved, to obtain an alkali leachate; a solid-liquid separation step on the alkali leachate to obtain a leach filtrate containing vanadium; an evaporation concentration step of evaporating and concentrating the leach filtrate to obtain a concentrated liquid; and a crystallization/solid-liquid separation step of cooling and crystalizing the concentrated liquid and recovering a precipitate containing a vanadium compound. Another production method includes an alkali extraction step, a solid-liquid separation step, an evaporation concentration step, an alkali concentration adjustment step of further adding an alkali or alkali solution to a concentrated liquid to obtain a concentration-adjusted liquid, and a crystallization/solid-liquid separation step.