Digestion of a laterite with sulfuric acid dissolves all constituents except silica. The resulting sulfatesaluminum sulfate, ferric sulfate, titanyl sulfate, and magnesium sulfateremain in solution at approximately 90 C. Hot filtration separates silica. Solution flow over iron reduces ferric sulfate to ferrous sulfate. Controlled ammonia addition promotes hydrolysis and precipitation of hydrated titania from titanyl sulfate that is removed by filtration. Addition of ammonium sulfate forms ferrous ammonium sulfate and ammonium aluminum sulfate solutions. Alum is preferentially separated by crystallization. Addition of ammonium bicarbonate to an ammonium alum solution precipitates ammonium aluminum carbonate which may be heated to produce alumina, ammonia, and carbon dioxide. The addition of oxalic acid generates insoluble ferrous oxalate which thermally decomposes to ferrous oxide and carbon monoxide which is used to reduce the ferrous oxide to metallic iron. Further oxalic acid addition precipitates magnesium oxalate which is thermally decomposed to magnesium oxide.

In the mining process, linear, branched, hyperbranched or dendrimeric polyols or mixtures thereof are employed as process stabilization aids for aqueous solutions and, or suspensions of metal salts. A specific application area of the polyols is the stabilization of bauxite liquor in the Bayer process of producing alumina from bauxite.

An improved beta(?)-spodumene (?LiAlSi.sub.2O.sub.6) nitric acid conversion process produces discrete lithium (Li), aluminum (Al) and silica (SiO.sub.2) materials by: (i) converting lithium nitrate, LiNO.sub.3, to lithium carbonate, Li.sub.2CO.sub.3; (ii) creating a Al-rich precipitate either by thermally decomposing aluminum nitrate, Al(NO.sub.3).sub.3, or by reacting Al(NO.sub.3).sub.3 with aqueous and/or solid ammonium carbonate, (NH.sub.4).sub.2CO.sub.3; and (iii) forming a solid SiO.sub.2-rich aluminosilicate residue by selectively leaching Li and Al from ?-spodumene. Three key reactants consumed during processingnitric acid (HNO.sub.3), ammonia (NH.sub.3), and magnesium oxide (MgO)may be regenerated internally by closed-loop chemical cycles, this feature of the process greatly improving its economics in commercial applications.

In order to recover high-quality scandium from nickel oxide ores efficiently, this method comprises: a step (S1) for feeding Ni oxide ores and sulfuric acid into a pressure vessel, and subjecting the mixture to solid-liquid separation to form a leachate and a leach residue; a step (S2) for adding a neutralizing agent to the leachate, and thus forming a neutralization sediment and a post-neutralization fluid; a step (S3) for adding a sulfurizing agent to the post-neutralization fluid, and separating the obtained mixture into Ni sulfide and a post-sulfurization fluid; a step (S4) for bringing the post-sulfurization fluid into contact with a chelating resin, making Sc adsorbed on the chelating resin, and forming an Sc eluent; a step (S6) for bringing the Sc eluent into contact with an extracting agent, adding a back-extraction agent to the extract, and forming back-extracted matter; and a step (S8) for roasting the back-extracted matter, and forming Sc oxide.

The present disclosure relates to processes for recovering rare earth elements from an aluminum-bearing material. The processes can comprise leaching the aluminum-bearing material with an acid so as to obtain a leachate comprising at least one aluminum ion, at least one iron ion, at least one rare earth element, and a solid, and separating the leachate from the solid. The processes can also comprise substantially selectively removing at least one of the at least one aluminum ion and the at least one iron ion from the leachate and optionally obtaining a precipitate. The processes can also comprise substantially selectively removing the at least one rare earth element from the leachate and/or the precipitate.

A process and system are disclosed for producing a lithium product from a solution comprising lithium nitrate. The solution comprising lithium nitrate can be obtained by reacting a lithium-containing metal silicate with nitric acid. The process and system comprise subjecting the solution comprising lithium nitrate to a first thermal treatment procedure (in one or more heated vessels) in which water and nitric acid (when present) are removed, and whereby a resultant lithium nitrate-rich crystal slurry is heated to produce a molten liquid. The process and system also comprise passing the molten liquid to a second thermal treatment procedure (in a further-heated vessel) in which the molten liquid is heated to substantially decompose lithium nitrate to lithium oxide.

It is described a process for extracting aluminum from aluminum-bearing materials comprising the steps of leaching the aluminum-bearing material with HCl to obtain aluminum chloride; separating and purifying the aluminum chloride; providing aluminum chloride to an electrolysis cell comprising an anode connected to a source of hydrogen gas delivering the hydrogen gas during use to the anode, and a cathode; passing an electric current from the anode through the cathode, depositing aluminum at the cathode; and draining the aluminum from the cathode.

The invention relates to metallurgy, particular to acid methods for producing alumina, and can used in processing aluminum-containing raw materials, including those of a low-grade. The method for producing alumina comprises treating aluminum-containing raw materials with hydrochloric acid, separating aluminum chloride hexahydrate crystals from the supernatant chloride solution, and thermally decomposing said crystals in two stages to produce alumina. In order to increase the quality of alumina and decrease energy consumption while achieving high process productivity, water vapor is continuously introduced during the second stage of thermal decomposition, with a ratio of the total mass of the introduced water vapor to the mass of produced alumina equal to 0.2-5.7.

The invention provides methods and compositions for improving dewatering of Bayer Process alumina trihydrate slurry. The method comprises adding an R-Succinic Compound (such as octadecenyl succinic acid, hexadecenyl succinic acid, and/or dodecenyl succinic acid) to the slurry. The R-Succinic Compound removes water that would otherwise be trapped within the filtered slurry cake and therefore reduces the energy needed to calcine the resulting solids.

The present invention relates to the technical field of comprehensive recovery and utilization of mineral resources, in particular to a method of extracting lithium from spodumene and meanwhile recovering low iron and low sulfur silicon aluminum micro-powder, high purity gypsum, tantalum niobium concentrate and lithium rich iron material. The method of the present invention comprises: mixing and leaching the lithium extraction acid clinker of spodumene with water; filtering the leached pulp to obtain the filtrate 1 and the filter residue 1; neutralizing the filtrate 1; filtering the neutralized pulp to obtain the filtrate 2 and high purity gypsum, extracting lithium from the filtrate 2 to obtain lithium salt; neutralizing and mixing the filter residue 1 to obtain the coarse and fine particles by classification; carrying out weak magnetic separation of fine particles to obtain lithium rich iron material and non-magnetic material; and carrying out strong magnetic separation, strong magnetic material gravity separation and tantalum niobium crude concentrate pickling on the non-magnetic material to obtain tantalum niobium concentrate. The present invention solves the major problem that the slag plaguing the lithium salt industry is difficult to deal with; and the present invention also gives priority to the separation of gypsum, which can simplify the subsequent treatment of lithium slag and provide high-quality low iron and low sulfur silicon aluminum micro-powder, high purity gypsum, tantalum niobium concentrate and lithium rich iron material.